Programmer's Guide Oracle Call Interface Programmers

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Oracle® Call Interface
Programmer's Guide

18c
E83799-03
September 2018

Oracle Call Interface Programmer's Guide, 18c
E83799-03
Copyright © 1996, 2018, Oracle and/or its affiliates. All rights reserved.
Primary Author: Mamata Basapur
Contributing Authors: Rod Ward
Contributors: D. Adams, G. Arora, V. Arora, A. Bande, D. Banerjee, S. Banerjee, M. Bastawala, E. Belden, P.
Betteridge, N. Bhatt, T. Bhosle, J. Blowney, R. Chakravarthula, S. Chandrasekar, B. Cheng, D. Chiba, L.
Chidambaran, C. Colrain, T. Das, Ronald Decker, A. Desai, A. Downing, S. Fogel, T. Hoang, N. Ikeda, K.
Itikarlapalli, C. Iyer, S. Iyer, V. Jitta, C. Jones, A. Keh, B. Khaladkar, S. Krishnaswamy, R. Kumar, R. Kumar,
S. Lahorani, S. Lari, T. H. Lee, T. Li, C. Liang, I. Listvinsky, J. Liu, E. Lu, S. Lynn, K.Mensah, V. Moore, A.
Mullick, K. Neel, M. Orgiyan, E. Paapanen, S. Pelski, R. Phillips, R. Pingte, R. Rajamani, M. Ramacher, A.
Ramappa, S. Sahu, A. Saxena, S. Seshadri, R. Singh, B. Sinha, H. Slattery, J. Stewart, L. Sun, S. Suresh, S.
Tata, H. Tran, A. Tuininga, S. Vallapureddy, M. Vemana, S. Vemuri, B. Venkatakrishnan, K. Verma, G.
Viswanathan, S. Wolicki, L. Wong, S. Youssef, B. Zebian
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Contents
Preface
Audience

lviii

Documentation Accessibility

lviii

Related Documents

lix

Conventions

lx

Changes in This Release for Oracle Call Interface Programmer's
Guide
Changes in Oracle Database Release 18c Version 18.1

1

lxi

OCI: Introduction
1.1

Overview of OCI

1-1

1.2

Building an OCI Application

1-3

1.3

Alternatives to OCI

1-3

1.4

SQL Statements

1-5

1.4.1

Data Definition Language

1-5

1.4.2

Control Statements

1-6

1.4.3

Data Manipulation Language

1-6

1.4.4

Queries

1-7

1.4.5

PL/SQL

1-7

1.4.6

Embedded SQL

1-8

1.4.7

Special OCI Terms for SQL

1-9

1.5

Procedural and Nonprocedural Elements

1.6

Object Support

1-9
1-10

1.6.1

Client-Side Object Cache

1-11

1.6.2

Associative and Navigational Interfaces

1-11

1.6.3

OCI Runtime Environment for Objects

1-12

1.6.4

Type Management: Mapping and Manipulation Functions

1-12

1.6.5

Object Type Translator

1-13

1.7

Simple Oracle Document Access (SODA)

1-13

1.8

Encapsulated Interfaces

1-14

iii

1.9

2

User Authentication and Password Management

1.10

Features to Improve Application Performance and Scalability

1-15

1.11

Oracle Streams Advanced Queuing

1-15

1.12

XA Library Support

1-16

Oracle Instant Client and Oracle Instant Client Light
2.1

About Oracle Instant Client

2-1

2.2

Install from ZIP Files, from RPMs, and from Oracle Universal Installer

2-3

2.3

Environment Variables for Oracle Instant Client

2-5

2.4

Database Connection Strings for Oracle Instant Client

2-6

2.5

SDK for Oracle Instant Client

2-7

2.6

About Oracle Instant Client Light

2-7

2.6.1

Globalization Settings

2-8

2.6.2

Libraries for Oracle Instant Client Light

2-9

2.6.3

Installing Oracle Instant Client Light

2-9

2.7

About Patching Oracle Instant Client Shared Libraries on Linux or UNIX

2-10

2.8

Regeneration of Data Shared Library and Zip and RPM Files

2-11

2.8.1

Regenerating Data Shared Library libociei.so

2-12

2.8.2

Regenerating Data Shared Library libociicus.so

2-12

2.8.3

Regenerating Data Shared Libraries libociei.so and libociicus.so in One
Step

2-12

2.8.4

Regenerating Zip and RPM Files for the Basic Package

2-13

2.8.5

Regenerating Zip and RPM Files for the Basic Light Package

2-13

2.8.6

Regenerating Zip and RPM Files for the JDBC Package

2-13

2.8.7

Regenerating Zip and RPM Files for the ODBC Package

2-13

2.8.8

Regenerating Zip and RPM Files for the SQL*Plus Package

2-13

2.8.9

Regenerating Zip and RPM Files for the Tools Package

2-13

2.8.10

3

1-14

Regenerating Zip and RPM Files for All Packages

2-13

Building and Configuring OCI Applications
3.1

Header File and Makefile Locations

3-1

3.2

Building an OCI Application on Linux and UNIX

3-2

3.2.1

Oracle Directory Structure

3-2

3.2.2

Demonstration OCI Programs

3-2

3.3

Building an Application on Windows

3-3

3.4

Database Connection Strings

3-3

3.4.1

Examples of Oracle Instant Client Connect Identifiers

3-4

3.5

Client and Server Operating with Different Versions of Time Zone Files

3-6

3.6

OCI Client-Side Deployment Parameters Using oraaccess.xml

3-7

3.6.1

About oraaccess.xml

3-7

iv

3.7

3.8

4

3.6.2

About Client-Side Deployment Parameters Specified in oraaccess.xml

3-7

3.6.3

High Level Structure of oraaccess.xml

3-8

3.6.4

About Specifying Global Parameters in oraaccess.xml

3-9

3.6.5

About Specifying Defaults for Connection Parameters

3-11

3.6.6

Overriding Connection Parameters at the Connection-String Level

3-13

3.6.7

About OCI Session Pool Configuration in oraaccess.xml

3-17

3.6.8

File (oraaccess.xml) Properties

3-18

About Compatibility and Upgrading

3-19

3.7.1

Oracle Client and Server Cross Version Compatibility

3-19

3.7.2

Version Compatibility of Statically Linked and Dynamically Linked
Applications

3-20

3.7.3

About Upgrading of Existing OCI Release 7 Applications

3-20

3.7.4

Obsolete OCI Routines

3-22

3.7.5

OCI Routines Not Supported

3-24

Fault Diagnosability in OCI

3-24

3.8.1

About Fault Diagnosability in OCI

3-24

3.8.2

ADR Base Location

3-25

3.8.3

Using ADRCI

3-26

3.8.4

Controlling ADR Creation and Disabling Fault Diagnosability Using
sqlnet.ora

3-28

OCI Programming Basics
4.1

Overview of OCI Program Programming

4-1

4.2

OCI Data Structures

4-3

4.2.1

4.3

Handles

4-3

4.2.1.1

About Allocating and Freeing Handles

4-5

4.2.1.2

Environment Handle

4-6

4.2.1.3

Error Handle

4-6

4.2.1.4

Service Context Handle and Associated Handles

4-6

4.2.1.5

Statement, Bind, and Define Handles

4-8

4.2.1.6

Describe Handle

4-9

4.2.1.7

Complex Object Retrieval Handle

4-9

4.2.1.8

Thread Handle

4-9

4.2.1.9

Subscription Handle

4-9

4.2.1.10

Direct Path Handles

4-10

4.2.1.11

Connection Pool Handle

4-10

4.2.1.12

Handle Attributes

4-10

4.2.1.13

OCI Descriptors

4-12

OCI Programming Steps
4.3.1

OCI Environment Initialization

4.3.1.1

About Creating the OCI Environment

4-17
4-18
4-18

v

4.4

4.3.1.2

About Allocating Handles and Descriptors

4-19

4.3.1.3

Application Initialization, Connection, and Session Creation

4-19

4.3.2

About Processing SQL Statements in OCI

4-25

4.3.3

Commit or Roll Back Operations

4-25

4.3.4

About Terminating the Application

4-26

4.3.5

Error Handling in OCI

4-27

4.3.5.1

Return and Error Codes for Data

4-28

4.3.5.2

Functions Returning Other Values

4-29

Additional Coding Guidelines

4-29

4.4.1

Operating System Considerations

4-29

4.4.2

Parameter Types

4-30

4.4.2.1

Address Parameters

4-30

4.4.2.2

Integer Parameters

4-30

4.4.2.3

Character String Parameters

4-31

4.4.3

Inserting Nulls into a Column

4-31

4.4.4

Indicator Variables

4-31

4.4.4.1

Input

4-32

4.4.4.2

Output

4-32

4.4.4.3

Indicator Variables for Named Data Types and REFs

4-32

4.4.5

About Canceling Calls

4-33

4.4.6

Positioned Updates and Deletes

4-34

4.4.7

Reserved Words

4-35

4.4.7.1

Oracle Reserved Namespaces

4-35

4.4.8

Polling Mode Operations in OCI

4-36

4.4.9

Nonblocking Mode in OCI

4-36

4.4.10

Setting Blocking Modes

4-37

4.4.11

Canceling a Nonblocking Call

4-38

4.5

About Using PL/SQL in an OCI Program

4-38

4.6

OCI Globalization Support

4-39

4.6.1

Client Character Set Control from OCI

4-40

4.6.2

Character Control and OCI Interfaces

4-40

4.6.3

Character-Length Semantics in OCI

4-41

4.6.4

Character Set Support in OCI

4-41

4.6.5

Controlling Language and Territory in OCI

4-41

4.6.6

Other OCI Globalization Support Functions

4-42

4.6.7

About Getting Locale Information in OCI

4-42

4.6.8

About OCI and the BOM (Byte Order Mark)

4-43

4.6.9

About Manipulating Strings in OCI

4-44

4.6.10

About Converting Character Sets in OCI

4-45

4.6.11

OCI Messaging Functions

4-46

4.6.12

lmsgen Utility

4-47

vi

5

4.6.12.1

Guidelines for Text Message Files

4-47

4.6.12.2

An Example of Creating a Binary Message File from a Text
Message File

4-48

Data Types
5.1

Oracle Data Types
5.1.1

5.2

5.3

About Using External Data Type Codes

Internal Data Types

5-1
5-3
5-4

5.2.1

LONG, RAW, LONG RAW, VARCHAR2

5-5

5.2.2

Character Strings and Byte Arrays

5-5

5.2.3

UROWID

5-6

5.2.4

BINARY_FLOAT and BINARY_DOUBLE

5-6

External Data Types
5.3.1

VARCHAR2

5-7
5-9

5.3.1.1

Input

5-10

5.3.1.2

Output

5-11

5.3.2

NUMBER

5-11

5.3.3

64-Bit Integer Host Data Type

5-12

5.3.3.1

OCI Bind and Define for 64-Bit Integers

5-13

5.3.3.2

Support for OUT Bind DML Returning Statements

5-13

5.3.4

INTEGER

5-14

5.3.5

FLOAT

5-15

5.3.6

STRING

5-15

5.3.6.1

Input

5-15

5.3.6.2

Output

5-16

5.3.7

VARNUM

5-16

5.3.8

LONG

5-16

5.3.9

VARCHAR

5-17

5.3.10

DATE

5-17

5.3.11

RAW

5-18

5.3.12

VARRAW

5-18

5.3.13

LONG RAW

5-19

5.3.14

UNSIGNED

5-19

5.3.15

LONG VARCHAR

5-19

5.3.16

LONG VARRAW

5-19

5.3.17

CHAR

5-19

5.3.17.1

Input

5-19

5.3.17.2

Output

5-20

5.3.18

CHARZ

5-21

5.3.19

Named Data Types: Object, VARRAY, Nested Table

5-21

5.3.20

REF

5-22

vii

5.3.21

ROWID Descriptor

5-22

5.3.22

LOB Descriptor

5-23

5.3.22.1

BFILE

5-24

5.3.22.2

BLOB

5-25

5.3.22.3

CLOB

5-25

5.3.22.4

NCLOB

5-25

5.3.23

5.4

ANSI DATE

5-26

5.3.23.2

TIMESTAMP

5-26

5.3.23.3

TIMESTAMP WITH TIME ZONE

5-26

5.3.23.4

TIMESTAMP WITH LOCAL TIME ZONE

5-27

5.3.23.5

INTERVAL YEAR TO MONTH

5-27

5.3.23.6

INTERVAL DAY TO SECOND

5-27

5.3.23.7

About Avoiding Unexpected Results Using Datetime

5-27

5.3.24

Native Float and Native Double

5-28

5.3.25

C Object-Relational Data Type Mappings

5-28

Data Conversions
Data Conversions for LOB Data Type Descriptors

5-30

5.4.2

Data Conversions for Datetime and Interval Data Types

5-30

5.4.2.1

Assignment Notes

5-31

5.4.2.2

Data Conversion Notes for Datetime and Interval Types

5-32

Datetime and Date Upgrading Rules

5-32

5.4.3.1

Pre-9.0 Client with 9.0 or Later Server

5-32

5.4.3.2

Pre-9.0 Server with 9.0 or Later Client

5-32

Data Conversion for BINARY_FLOAT and BINARY_DOUBLE in OCI

Typecodes
5.5.1

6

5-28

5.4.1

5.4.4

5.6

5-25

5.3.23.1

5.4.3

5.5

Datetime and Interval Data Type Descriptors

5-33
5-34

Relationship Between SQLT and OCI_TYPECODE Values

Definitions in oratypes.h

5-35
5-37

Using SQL Statements in OCI
6.1

Overview of SQL Statement Processing

6-1

6.2

About Preparing Statements

6-4

6.2.1
6.3

About Binding Placeholders in OCI
6.3.1

6.4

About Using Prepared Statements on Multiple Servers

6-5
6-6

Rules for Placeholders

6-7

About Executing Statements

6-7

6.4.1

Execution Snapshots

6-8

6.4.2

Execution Modes of OCIStmtExecute()

6-9

6.4.2.1

Using Batch Error Mode

6.4.2.2

Example of Batch Error Mode

6-9
6-11

viii

6.5

6-12

6.5.1

Implicit Describe

6-13

6.5.2

Explicit Describe of Queries

6-15

6.6

About Defining Output Variables in OCI

6-16

6.7

About Fetching Results

6-16

6.8

7

About Describing Select-List Items

6.7.1

About Fetching LOB Data

6-17

6.7.2

About Setting Prefetch Count

6-17

About Using Scrollable Cursors in OCI

6-19

6.8.1

About Increasing Scrollable Cursor Performance

6-20

6.8.2

Example of Access on a Scrollable Cursor

6-21

Binding and Defining in OCI
7.1

7.2

Overview of Binding in OCI
7.1.1

Named Binds and Positional Binds

7-3

7.1.2

OCI Array Interface

7-4

7.1.3

About Binding Placeholders in PL/SQL

7-5

7.1.4

Steps Used in OCI Binding

7-6

7.1.5

PL/SQL Block in an OCI Program

7-7

Advanced Bind Operations in OCI
7.2.1

7.3

7-10

Binding LOB Locators

7-10

7.2.1.2

About Binding LOB Data

7-12

7.2.2

About Binding in OCI_DATA_AT_EXEC Mode

7-16

7.2.3

About Binding REF CURSOR Variables

7-17

Overview of Defining in OCI
Steps Used in OCI Defining

Advanced Define Operations in OCI
7.4.1

7.5

About Binding LOBs

7-9

7.2.1.1

7.3.1
7.4

7-1

About Defining LOB Output Variables

7-17
7-18
7-19
7-20

7.4.1.1

About Defining LOB Locators

7-20

7.4.1.2

About Defining LOB Data

7-21

7.4.2

About Defining PL/SQL Output Variables

7-22

7.4.3

About Defining for a Piecewise Fetch

7-22

About Binding and Defining Arrays of Structures in OCI
7.5.1

Skip Parameters

7.5.1.1

Skip Parameters for Standard Arrays

7-22
7-23
7-24

7.5.2

OCI Calls Used with Arrays of Structures

7-24

7.5.3

Arrays of Structures and Indicator Variables

7-25

7.6

About Binding and Defining Multiple Buffers

7-25

7.7

DML with a RETURNING Clause in OCI

7-29

7.7.1

About Using DML with a RETURNING Clause to Combine Two SQL
Statements

7-29

ix

7.7.2

About Binding RETURNING...INTO Variables

7-30

7.7.3

OCI Error Handling

7-31

7.7.4

DML with RETURNING REF...INTO Clause in OCI

7-31

7.7.4.1

7-31

7.7.5

Additional Notes About OCI Callbacks

7-33

7.7.6

Array Interface for DML RETURNING Statements in OCI

7-33

7.8

Character Conversion in OCI Binding and Defining
7.8.1

About Choosing a Character Set

7-33
7-34

7.8.1.1

Character Set Form and ID

7-34

7.8.1.2

Implicit Conversion Between CHAR and NCHAR

7-35

7.8.2

About Setting Client Character Sets in OCI

7-36

7.8.3

About Binding Variables in OCI

7-36

7.9

7.8.3.1

About Using the OCI_ATTR_MAXDATA_SIZE Attribute

7-37

7.8.3.2

About Using the OCI_ATTR_MAXCHAR_SIZE Attribute

7-37

7.8.3.3

Buffer Expansion During OCI Binding

7-38

7.8.3.4

Constraint Checking During Defining

7-39

7.8.3.5

General Compatibility Issues for Character-Length Semantics in
OCI

7-40

PL/SQL REF CURSORs and Nested Tables in OCI

7-43

7.10

Natively Describe and Bind All PL/SQL Types Including Package Types

7-44

7.11

Runtime Data Allocation and Piecewise Operations in OCI

7-45

7.11.1

Valid Data Types for Piecewise Operations

7-46

7.11.2

Types of Piecewise Operations

7-46

7.11.3

About Providing INSERT or UPDATE Data at Runtime

7-47

7.11.3.1

Performing a Piecewise Insert or Update

7-48

7.11.4

Piecewise Operations with PL/SQL

7-50

7.11.5

PL/SQL Indexed Table Binding Support

7-50

7.11.5.1
7.11.6
7.11.7

Restrictions for PL/SQL Indexed Table Binding Interface

About Providing FETCH Information at Run Time

7.11.6.1

8

Binding the Output Variable

Performing a Piecewise Fetch

Piecewise Binds and Defines for LOBs

7-51
7-52
7-52
7-54

Describing Schema Metadata
8.1

8.2

About Using OCIDescribeAny()

8-1

8.1.1

Limitations on OCIDescribeAny()

8-3

8.1.2

Notes on Types and Attributes

8-3

8.1.2.1

Data Type Codes

8-3

8.1.2.2

About Describing Types

8-4

8.1.2.3

Implicit and Explicit Describe Operations

8-4

8.1.2.4

OCI_ATTR_LIST_ARGUMENTS Attribute

8-5

Parameter Attributes

8-5

x

8.3

8.2.1

Table or View Parameters

8-7

8.2.2

Procedure, Function, and Subprogram Attributes

8-8

8.2.3

Package Attributes

8-9

8.2.4

Type Attributes

8-9

8.2.5

Type Attribute Attributes

8-11

8.2.6

Type Method Attributes

8-12

8.2.7

Collection Attributes

8-13

8.2.8

Synonym Attributes

8-14

8.2.9

Sequence Attributes

8-15

8.2.10

Column Attributes

8-15

8.2.11

Argument and Result Attributes

8-19

8.2.12

List Attributes

8-20

8.2.13

Schema Attributes

8-21

8.2.14

Database Attributes

8-21

8.2.15

Rule Attributes

8-22

8.2.16

Rule Set Attributes

8-23

8.2.17

Evaluation Context Attributes

8-23

8.2.18

Table Alias Attributes

8-24

8.2.19

Variable Type Attributes

8-24

8.2.20

Name Value Attributes

8-25

Character-Length Semantics Support in Describe Operations
8.3.1

Implicit Describing

8-26

8.3.2

Explicit Describing

8-26

8.3.2.1
8.4

9

8-25

Client and Server Compatibility Issues for Describing

Examples Using OCIDescribeAny()

8-26
8-27

8.4.1

Retrieving Column Data Types for a Table

8-27

8.4.2

Describing the Stored Procedure

8-29

8.4.3

Retrieving Attributes of an Object Type

8-30

8.4.4

Retrieving the Collection Element's Data Type of a Named Collection
Type

8-32

8.4.5

Describing with Character-Length Semantics

8-34

8.4.6

Describing Each Column to Know Whether It Is an Invisible Column

8-35

LOB and BFILE Operations
9.1

About Using OCI Functions for LOBs

9-1

9.2

About Creating and Modifying Persistent LOBs

9-2

9.3

About Associating a BFILE in a Table with an Operating System File

9-3

9.4

LOB Attributes of an Object

9-3

9.5

9.4.1

Writing to a LOB Attribute of an Object

9-4

9.4.2

Transient Objects with LOB Attributes

9-4

Array Interface for LOBs

9-5

xi

9.6

About Using LOBs of Size Greater than 4 GB
9.6.1

Functions to Use for the Increased LOB Sizes

9-6

9.6.2

Compatibility and Migration

9-7

LOB and BFILE Functions in OCI

9-9

9.7

9.7.1

About Improving LOB Read/Write Performance

9-10

9.7.1.1

About Using Data Interface for LOBs

9-10

9.7.1.2

About Using OCILobGetChunkSize()

9-11

9.7.1.3

About Using OCILobWriteAppend2()

9-11

9.7.1.4

About Using OCILobArrayRead() and OCILobArrayWrite()

9-12

9.7.2

LOB Buffering Functions

9-12

9.7.3

Functions for Opening and Closing LOBs

9-13

9.7.3.1
9.7.4

9.8

Restrictions on Opening and Closing LOBs

LOB Read and Write Callbacks

9-14
9-15

9.7.4.1

Callback Interface for Streaming

9-15

9.7.4.2

Reading LOBs by Using Callbacks

9-15

9.7.4.3

Writing LOBs by Using Callbacks

9-17

Temporary LOB Support

9-18

9.8.1

Creating and Freeing Temporary LOBs

9-19

9.8.2

Temporary LOB Durations

9-20

9.8.3

About Freeing Temporary LOBs

9-21

9.8.4

Take Care When Assigning Pointers

9-21

9.8.5

Temporary LOB Example

9-22

9.9

Prefetching of LOB Data, Length, and Chunk Size

9.10

10

9-5

Options of SecureFiles LOBs

9-25
9-28

Managing Scalable Platforms
10.1

OCI Support for Transactions

10-1

10.2

Levels of Transactional Complexity

10-2

10.2.1

Simple Local Transactions

10-2

10.2.2

Serializable or Read-Only Local Transactions

10-3

10.2.3

Global Transactions

10-3

10.2.3.1

Transaction Identifiers

10-3

10.2.3.2

Attribute OCI_ATTR_TRANS_NAME

10-4

10.2.3.3

Transaction Branches

10-4

10.2.3.4

Branch States

10-6

10.2.3.5

Detaching and Resuming Branches

10-6

10.2.3.6

About Setting the Client Database Name

10-6

10.2.3.7

One-Phase Commit Versus Two-Phase Commit

10-7

10.2.3.8

Preparing Multiple Branches in a Single Message

10-7

10.2.4

Transaction Examples

10-8

xii

10.2.5

10.3

Initialization Parameters

10-8

10.2.5.1

Showing Update Successfully, One-Phase Commit

10-9

10.2.5.2

Showing Starting a Transaction, Detach, Resume, Prepare,
Two-Phase Commit

10-9

10.2.5.3

Showing a Read-Only Update Fails

10-10

10.2.5.4

Showing Starting a Read-Only Transaction, Select, and Commit

10-10

Password and Session Management

10-11

10.3.1

OCI Authentication Management

10-11

10.3.2

OCI Password Management

10-13

10.3.3

Secure External Password Store

10-13

10.3.4

OCI Session Management

10-14

10.4

Middle-Tier Applications in OCI

10.4.1

10.5

10-16

10.4.1.1

OCI_CRED_PROXY

10-16

10.4.1.2

OCI_ATTR_PROXY_CREDENTIALS

10-16

10.4.1.3

OCI_ATTR_DISTINGUISHED_NAME

10-17

10.4.1.4

OCI_ATTR_CERTIFICATE

10-17

10.4.1.5

OCI_ATTR_INITIAL_CLIENT_ROLES

10-18

10.4.1.6

OCI_ATTR_CLIENT_IDENTIFIER

10-18

10.4.1.7

OCI_ATTR_PASSWORD

10-19

Externally Initialized Context in OCI

10.5.1

Externally Initialized Context Attributes in OCI

10-22
10-22

10.5.1.1

OCI_ATTR_APPCTX_SIZE

10-23

10.5.1.2

OCI_ATTR_APPCTX_LIST

10-23

10.5.1.3

Session Handle Attributes Used to Set an Externally Initialized
Context

10-23

10.5.2

End-to-End Application Tracing

10-24

10.5.2.1

OCI_ATTR_COLLECT_CALL_TIME

10-24

10.5.2.2

OCI_ATTR_CALL_TIME

10-25

10.5.2.3

Attributes for End-to-End Application Tracing

10-25

10.5.3
10.6

OCI Attributes for Middle-Tier Applications

10-15

Using OCISessionBegin() with an Externally Initialized Context

Client Application Context

10-26
10-28

10.6.1

Using Multiple SET Operations

10-29

10.6.2

Using CLEAR-ALL Operations Between SET Operations

10-29

10.6.3

Network Transport and PL/SQL on Client Namespace

10-30

10.7

Using Edition-Based Redefinition

10-31

10.8

OCI Security Enhancements

10-32

10.8.1

Controlling the Database Version Banner Displayed

10-32

10.8.2

Banners for Unauthorized Access and User Actions Auditing

10-33

10.8.3

Non-Deferred Linkage

10-34

10.9

Overview of OCI Multithreaded Development

10.9.1

Advantages of OCI Thread Safety

10-34
10-35

xiii

10.9.2

OCI Thread Safety and Three-Tier Architectures

10-35

10.9.3

About Implementing Thread Safety

10-35

10.10

10.9.3.1

About Polling Mode Operations and Thread Safety

10-37

10.9.3.2

Mixing 7.x and Later Release OCI Calls

10-37

OCIThread Package

10.10.1

Initialization and Termination

10.10.1.1
10.10.2

Passive Threading Primitives

10-38
10-39
10-39

10.10.2.1

OCIThreadMutex

10-40

10.10.2.2

OCIThreadKey

10-41

10.10.2.3

OCIThreadKeyDestFunc

10-41

10.10.2.4

OCIThreadId

10-42

10.10.3

Active Threading Primitives

10.10.3.1

11

OCIThread Context

10-37

OCIThreadHandle

10-42
10-43

Session Pooling and Connection Pooling in OCI
11.1

Session Pooling in OCI

11-1

11.1.1

Functionality of OCI Session Pooling

11-2

11.1.2

Homogeneous and Heterogeneous Session Pools

11-2

11.1.3

About Using Tags in Session Pools

11-2

11.1.3.1
11.1.4

Multi-Property Tags

OCI Handles for Session Pooling

11-3
11-6

11.1.4.1

OCISPool

11-6

11.1.4.2

OCIAuthInfo

11-6

11.1.5

Using OCI Session Pooling

11-7

11.1.6

OCI Calls for Session Pooling

11-8

11.1.6.1

Allocate the Pool Handle

11-9

11.1.6.2

Create the Pool Session

11-9

11.1.6.3

Log On to the Database

11-9

11.1.6.4

Log Off from the Database

11-10

11.1.6.5

Destroy the Session Pool

11-11

11.1.6.6

Free the Pool Handle

11-11

Example of OCI Session Pooling

11-11

11.1.7
11.2

Database Resident Connection Pooling

11-11

11.3

About Using Oracle Connection Manager in Traffic Director Mode

11-12

11.4

Connection Pooling in OCI

11-15

11.4.1

OCI Connection Pooling Concepts

11-15

11.4.1.1

Similarities and Differences from a Shared Server

11-15

11.4.1.2

Stateless Sessions Versus Stateful Sessions

11-16

11.4.1.3

Multiple Connection Pools

11-16

xiv

11.4.1.4
11.4.2

12

Using OCI Calls for Connection Pooling

11-17
11-17

11.4.2.1

Allocate the Pool Handle

11-18

11.4.2.2

Create the Connection Pool

11-18

11.4.2.3

Log On to the Database

11-19

11.4.2.4

Deal with SGA Limitations in Connection Pooling

11-21

11.4.2.5

Log Off from the Database

11-22

11.4.2.6

Destroy the Connection Pool

11-22

11.4.2.7

Free the Pool Handle

11-23

11.4.3
11.5

Transparent Application Failover

Examples of OCI Connection Pooling

When to Use Connection Pooling, Session Pooling, or Neither

11-23
11-23

11.5.1

Functions for Session Creation

11-24

11.5.2

About Choosing Between Different Types of OCI Sessions

11-25

High Availability in OCI
12.1

Runtime Connection Load Balancing

12-1

12.2

HA Event Notification

12-2

12.2.1

OCIEvent Handle

12-3

12.2.2

OCI Failover for Connection and Session Pools

12-3

12.2.3

OCI Failover for Independent Connections

12-4

12.2.4

Event Callback

12-4

12.2.5

Custom Pooling: Tagged Server Handles

12-5

12.2.6

About Determining Transparent Application Failover (TAF) Capabilities

12-6

12.3

Transparent Application Failover in OCI

12-7

12.3.1

About Configuring Transparent Application Failover

12-8

12.3.2

Transparent Application Failover Callbacks in OCI

12-8

12.3.3

Transparent Application Failover Callback Structure and Parameters

12-9

12.3.4

Failover Callback Structure and Parameters

12-10

12.3.5

Failover Callback Registration

12-11

12.3.6

Failover Callback Example

12-11

12.3.7

Handling OCI_FO_ERROR

12-13

12.4

OCI and Transaction Guard

12.4.1

12.5

Developing Applications that Use Transaction Guard

12-14
12-15

12.4.1.1

Typical Transaction Guard Usage

12-16

12.4.1.2

Transaction Guard Examples

12-17

OCI and Application Continuity

12-22

12.5.1

About Added Support for Application Continuity

12-23

12.5.2

What Happens Following a Recoverable Error

12-23

12.5.3

Criteria for Successful Replay

12-24

12.5.4

What Factors Disable Application Continuity in OCI

12-24

xv

12.5.5

Failed Replay

12-25

12.5.6

When Is Application Continuity Most Effective

12-25

12.5.6.1

When Application Continuity in OCI Can Fail Over

12-26

12.5.6.2

Application Continuity in OCI Does Not Support These
Constructs

12-27

Possible Side Effects of Application Continuity

12-27

12.5.6.3

13

Notification Methods and Streams Advanced Queuing
13.1

About Continuous Query Notification

13-1

13.2

Publish-Subscribe Notification in OCI

13-2

13.2.1

Publish-Subscribe Registration Functions in OCI

13.2.1.1

Publish-Subscribe Register Directly to the Database

13-4

13.2.1.2

Open Registration for Publish-Subscribe

13-8

13.2.1.3

Using OCI to Open Register with LDAP

13-9

13.2.1.4

Setting QOS, Timeout Interval, Namespace, Client Address, and
Port Number

13-10

OCI Functions Used to Manage Publish-Subscribe Notification

13-11

13.2.1.5
13.2.2

Notification Callback in OCI

13-12

13.2.3

Notification Procedure

13-14

13.2.4

Publish-Subscribe Direct Registration Example

13-15

13.2.5

Publish-Subscribe LDAP Registration Example

13-20

13.3

14

13-4

OCI and Streams Advanced Queuing

13-22

13.3.1

OCI Streams Advanced Queuing Functions

13-23

13.3.2

OCI Streams Advanced Queuing Descriptors

13-23

13.3.3

Streams Advanced Queuing in OCI Versus PL/SQL

13-24

13.3.4

Using Buffered Messaging

13-29

User-Defined Callback Functions in OCI
14.1

About Registering User Callbacks in OCI

14-1

14.1.1

OCIUserCallbackRegister

14-3

14.1.2

User Callback Function

14-3

14.1.3

User Callback Control Flow

14-4

14.1.4

User Callback for OCIErrorGet()

14-5

14.1.5

Errors from Entry Callbacks

14-6

14.1.6

Dynamic Callback Registrations

14-6

14.1.7

About Loading Multiple Packages

14-6

14.1.8

Package Format

14-7

14.1.9

User Callback Chaining

14-8

14.1.10

About Accessing Other Data Sources Through OCI

14-8

14.1.11

Restrictions on Callback Functions

14-8

xvi

14.1.12
14.2

15

OCI Callbacks from External Procedures

14-11

Statement Caching in OCI

15-1

15.1.1

Statement Caching Without Session Pooling in OCI

15-2

15.1.2

Statement Caching with Session Pooling in OCI

15-2

15.1.3

Rules for Statement Caching in OCI

15-3

15.1.4

Bind and Define Optimization in Statement Caching

15-5

15.1.5

OCI Statement Caching Code Example

15-6

15.2

17

14-9

Performance Topics
15.1

16

Example of OCI Callbacks

Implicit Fetching of ROWIDs

15-6

15.2.1

About Implicit Fetching of ROWIDs

15-6

15.2.2

Example of Implicit Fetching of ROWIDs

15-8

15.3

OCI Support for Implicit Results

15-9

15.4

Client Result Cache

15-12

15.5

Client Statement Cache Auto-Tuning

15-12

15.5.1

About Auto-Tuning Client Statement Cache

15-12

15.5.2

Benefit of Auto-Tuning Client Statement Cache

15-13

15.5.3

Client Statement Cache Auto-Tuning Parameters

15-13

15.5.3.1



15-14

15.5.3.2



15-14

15.5.3.3

Comparison of the Connection Specific Auto-Tuning Parameters

15-16

15.5.4

Usage Examples of Client Statement Cache Auto Tuning

15-18

15.5.5

Enabling and Disabling OCI Client Auto-Tuning

15-19

15.5.6

Usage Guidelines for Auto-Tuning Client Statement Cache

15-19

Database Startup and Shutdown
16.1

About OCI Database Startup and Shutdown

16-1

16.2

Examples of Startup and Shutdown in OCI

16-2

Support for Pluggable Databases
17.1

Enhancements on OCI API Calls with Multitenant Container Databases
(CDB) in General

17-1

17.2

OCI Enhancements for ALTER SESSION SET CONTAINER

17-2

17.3

Restrictions on OCI API Calls with Multitenant Container Databases (CDB)
in General

17-2

Restrictions on OCI Calls with ALTER SESSION SET CONTAINER

17-3

17.4

xvii

17.5

18

17-4

OCI Interface for Using Shards
18.1
18.2

19

Restrictions on OCI Calls with ALTER SESSION SWITCH CONTAINER
SWITCH SERVICE

About Specifying a Sharding Key and Super Sharding Key for Getting a
Connection from an OCI Session Pool

18-5

About Specifying a Sharding Key and Super Sharding Key for Getting a
Connection from a Custom Pool

18-6

OCI Object-Relational Programming
19.1

OCI Object Overview

19-1

19.2

About Working with Objects in OCI

19-2

19.2.1

Basic Object Program Structure

19-3

19.2.2

Persistent Objects, Transient Objects, and Values

19-4

19.3

19.2.2.1

Persistent Objects

19-4

19.2.2.2

Transient Objects

19-5

19.2.2.3

Values

19-6

About Developing an OCI Object Application

19-6

19.3.1

About Representing Objects in C Applications

19-8

19.3.2

About Initializing the Environment and the Object Cache

19-9

19.3.3

About Making Database Connections

19-10

19.3.4

Retrieving an Object Reference from the Server

19-10

19.3.5

Pinning an Object

19-11

19.3.5.1

Array Pin

19-13

19.3.6

Manipulating Object Attributes

19-13

19.3.7

About Marking Objects and Flushing Changes

19-15

19.3.8

Fetching Embedded Objects

19-15

19.3.9

Object Meta-Attributes

19-17

19.3.9.1

Persistent Object Meta-Attributes

19-17

19.3.9.2

Additional Attribute Functions

19-19

19.3.9.3

Transient Object Meta-Attributes

19-20

19.3.10

Complex Object Retrieval

19-20

19.3.10.1

About Prefetching Objects

19-22

19.3.10.2

About Implementing Complex Object Retrieval in OCI

19-23

19.3.11

COR Prefetching

19-24

19.3.11.1

COR Interface

19-24

19.3.11.2

Example of COR

19-25

19.3.12

OCI Versus SQL Access to Objects

19-26

19.3.13

Pin Count and Unpinning

19-28

19.3.14

NULL Indicator Structure

19-28

xviii

19.3.15

About Creating Objects

19.3.15.1

19-31

19.3.16

About Freeing and Copying Objects

19-33

19.3.17

Object Reference and Type Reference

19-33

19.3.18

Create Objects Based on Object Views and Object Tables with
Primary-Key-Based OIDs

19-34

Error Handling in Object Applications

19-35

19.3.19
19.4

About Type Inheritance

19-35

19.4.1

Substitutability

19-37

19.4.2

NOT INSTANTIABLE Types and Methods

19-37

19.4.3

OCI Support for Type Inheritance

19-38

19.4.3.1

OCIDescribeAny()

19-38

19.4.3.2

Bind and Define Functions

19-38

19.4.3.3

OCIObjectGetTypeRef()

19-39

19.4.3.4

OCIObjectCopy()

19-39

19.4.3.5

OCICollAssignElem()

19-39

19.4.3.6

OCICollAppend()

19-40

19.4.3.7

OCICollGetElem()

19-40

19.4.4
19.5

20

Attribute Values of New Objects

19-31

OTT Support for Type Inheritance

About Type Evolution

19-40
19-41

Object-Relational Data Types in OCI
20.1

Overview of OCI Functions for Objects

20-1

20.2

About Mapping Oracle Data Types to C

20-2

20.2.1
20.3

OCI Type Mapping Methodology

20-3

About Manipulating C Data Types with OCI

20-4

20.3.1
20.4

Date (OCIDate)

20.4.1
20.5

Precision of Oracle Number Operations
Date Example

Datetime and Interval (OCIDateTime, OCIInterval)

20-5
20-5
20-6
20-7

20.5.1

About Datetime Functions

20.5.2

Datetime Example

20-10

20.5.3

About Interval Functions

20-10

20.6

Number (OCINumber)

20.6.1
20.7

OCINumber Examples

Fixed or Variable-Length String (OCIString)

20-8

20-12
20-12
20-14

20.7.1

About String Functions

20-15

20.7.2

String Example

20-15

20.8

Raw (OCIRaw)

20-16

20.8.1

About Raw Functions

20-16

20.8.2

Raw Example

20-17

xix

20.9

Collections (OCITable, OCIArray, OCIColl, OCIIter)

20-17

20.9.1

Generic Collection Functions

20-18

20.9.2

About Collection Data Manipulation Functions

20-19

20.9.3

About Collection Scanning Functions

20-19

20.9.4

Varray/Collection Iterator Example

20-20

20.9.5

About Nested Table Manipulation Functions

20-21

20.9.5.1
20.9.6
20.10

20-21

Nested Table Locators

20-22

About Multilevel Collection Types

20-22

20.10.1
20.11

Nested Table Element Ordering

Multilevel Collection Type Example

REF (OCIRef)

20-23
20-24

20.11.1

About REF Manipulation Functions

20-24

20.11.2

REF Example

20-25

20.12

Object Type Information Storage and Access

20.12.1
20.13

Descriptor Objects

AnyType, AnyData, and AnyDataSet Interfaces

20.13.1

About Type Interfaces

20-25
20-25
20-26
20-27

20.13.1.1

About Creating a Parameter Descriptor for OCIType Calls

20-28

20.13.1.2

About Obtaining the OCIType for Persistent Types

20-30

20.13.1.3

Type Access Calls

20-30

20.13.1.4

Extensions to OCIDescribeAny()

20-30

20.13.2

About OCIAnyData Interfaces

20-31

20.13.3

NCHAR Typecodes for OCIAnyData Functions

20-32

20.13.4

About OCIAnyDataSet Interfaces

20-32

20.14

About Binding Named Data Types

20-33

20.14.1

Named Data Type Binds

20-33

20.14.2

About Binding REFs

20-34

20.14.3

Information for Named Data Type and REF Binds

20-35

20.14.4

Information Regarding Array Binds

20-35

20.15

About Defining Named Data Types

20-36

20.15.1

About Defining Named Data Type Output Variables

20-36

20.15.2

About Defining REF Output Variables

20-37

20.15.3

Information for Named Data Type and REF Defines, and PL/SQL
OUT Binds

20-37

20.15.3.1
20.16

Information About Array Defines

About Binding and Defining Oracle C Data Types

20-39
20-39

20.16.1

Bind and Define Examples

20-41

20.16.2

Salary Update Examples

20-42

20.16.2.1

Method 1 - Fetch, Convert, Assign

20-43

20.16.2.2

Method 2 - Fetch and Assign

20-44

20.16.2.3

Method 3 - Direct Fetch

20-44

xx

20.16.2.4
20.17

21

Summary and Notes

SQLT_NTY Bind and Define Examples

20-45
20-45

20.17.1

SQLT_NTY Bind Example

20-46

20.17.2

SQLT_NTY Define Example

20-47

Direct Path Load Interface
21.1

Direct Path Loading Overview

21-1

21.1.1

Data Types Supported for Direct Path Loading

21-3

21.1.2

Direct Path Handles

21-4

21.1.2.1

Direct Path Context

21-4

21.1.2.2

OCI Direct Path Function Context

21-5

21.1.2.3

Direct Path Column Array and Direct Path Function Column
Array

21-6

Direct Path Stream

21-6

21.1.2.4
21.1.3

About Direct Path Interface Functions

21-7

21.1.4

Limitations and Restrictions of the Direct Path Load Interface

21-8

21.1.5

Direct Path Load Examples for Scalar Columns

21-9

21.1.5.1

Data Structures Used in Direct Path Loading Example

21-9

21.1.5.2

Outline of an Example of a Direct Path Load for Scalar Columns

21-11

21.1.6

21-14

21.1.6.1

OCI_ATTR_DIRPATH_DCACHE_SIZE

21-15

21.1.6.2

OCI_ATTR_DIRPATH_DCACHE_NUM

21-15

21.1.6.3

OCI_ATTR_DIRPATH_DCACHE_MISSES

21-15

21.1.6.4

OCI_ATTR_DIRPATH_DCACHE_HITS

21-15

21.1.6.5

OCI_ATTR_DIRPATH_DCACHE_DISABLE

21-15

21.1.7
21.2

About Using a Date Cache in Direct Path Loading of Dates in OCI

About Validating Format for Oracle NUMBER and DATE Data

Direct Path Loading of Object Types

21.2.1

Direct Path Loading of Nested Tables

21.2.1.1
21.2.2

Describing a Nested Table Column and Its Nested Table

Direct Path Loading of Column Objects

21-16
21-16
21-17
21-17
21-18

21.2.2.1

Describing a Column Object

21-18

21.2.2.2

Allocating the Array Column for the Column Object

21-20

21.2.2.3

Loading Column Object Data into the Column Array

21-20

21.2.2.4

OCI_DIRPATH_COL_ERROR

21-21

Direct Path Loading of SQL String Columns

21-21

21.2.3

21.2.3.1

Describing a SQL String Column

21-22

21.2.3.2

Allocating the Column Array for SQL String Columns

21-23

21.2.3.3

Loading the SQL String Data into the Column Array

21-24

21.2.4

Direct Path Loading of REF Columns

21-24

21.2.4.1

Describing the REF Column

21-25

21.2.4.2

Allocating the Column Array for a REF Column

21-27

xxi

21.2.4.3
21.2.5

Direct Path Loading of NOT FINAL Object and REF Columns

21-27
21-28

21.2.5.1

Inheritance Hierarchy

21-28

21.2.5.2

About Describing a Fixed, Derived Type to Be Loaded

21-29

21.2.5.3

About Allocating the Column Array

21-30

21.2.5.4

About Loading the Data into the Column Array

21-30

21.2.6

Direct Path Loading of Object Tables

21-30

21.2.7

Direct Path Loading a NOT FINAL Object Table

21-31

21.3

Direct Path Loading in Pieces

21.3.1
21.4

Loading Object Types in Pieces

Direct Path Context Handles and Attributes for Object Types

21.4.1

Direct Path Context Attributes

21.4.1.1
21.4.2

OCI_ATTR_DIRPATH_OBJ_CONSTR

Direct Path Function Context and Attributes

21-32
21-33
21-33
21-34
21-34
21-34

21.4.2.1

OCI_ATTR_DIRPATH_OBJ_CONSTR

21-35

21.4.2.2

OCI_ATTR_NAME

21-35

21.4.2.3

OCI_ATTR_DIRPATH_EXPR_TYPE

21-36

21.4.2.4

OCI_ATTR_DIRPATH_NO_INDEX_ERRORS

21-37

21.4.2.5

OCI_ATTR_NUM_COLS

21-37

21.4.2.6

OCI_ATTR_NUM_ROWS

21-38

21.4.3

Direct Path Column Parameter Attributes

21-38

21.4.3.1

OCI_ATTR_NAME

21-39

21.4.3.2

OCI_ATTR_DIRPATH_SID

21-41

21.4.3.3

OCI_ATTR_DIRPATH_OID

21-41

21.4.4

Direct Path Function Column Array Handle for Nonscalar Columns

21.4.4.1

22

Loading the REF Data into the Column Array

OCI_ATTR_NUM_ROWS Attribute

21-41
21-42

Object Advanced Topics in OCI
22.1

Object Cache and Memory Management

22-1

22.1.1

Cache Consistency and Coherency

22-4

22.1.2

Object Cache Parameters

22-4

22.1.3

Object Cache Operations

22-5

22.1.3.1

About Pinning and Unpinning

22-5

22.1.3.2

About Freeing

22-6

22.1.3.3

About Marking and Unmarking

22-6

22.1.3.4

About Flushing

22-6

22.1.3.5

About Refreshing

22-6

22.1.4

About Loading and Removing Object Copies

22-6

22.1.4.1

About Pinning an Object Copy

22-7

22.1.4.2

About Unpinning an Object Copy

22-8

xxii

22.1.4.3
22.1.5

About Making Changes to Object Copies

22-9
22-9

22.1.5.1

About Marking an Object Copy

22-10

22.1.5.2

About Unmarking an Object Copy

22-10

22.1.6

About Synchronizing Object Copies with the Server

22-11

22.1.6.1

About Flushing Changes to the Server

22-11

22.1.6.2

About Refreshing an Object Copy

22-12

22.1.7

Object Locking

22-13

22.1.7.1

Lock Options

22-13

22.1.7.2

About Locking Objects for Update

22-13

22.1.7.3

About Locking with the NOWAIT Option

22-14

22.1.7.4

About Implementing Optimistic Locking

22-14

22.1.8

Commit and Rollback in Object Applications

22-15

22.1.9

Object Duration

22-15

22.1.9.1
22.1.10
22.2
22.3

Durations Example

Memory Layout of an Instance

Object Navigation

22.2.1

Simple Object Navigation

OCI Navigational Functions

22-16
22-17
22-18
22-18
22-21

22.3.1

About Pin/Unpin/Free Functions

22-22

22.3.2

About Flush and Refresh Functions

22-22

22.3.3

About Mark and Unmark Functions

22-22

22.3.4

About Object Meta-Attribute Accessor Functions

22-23

22.3.5

About Other Functions

22-23

22.4

23

About Freeing an Object Copy

Type Evolution and the Object Cache

22-23

OCI Support for XML
23.1

XML Context

23-1

23.2

XML Data on the Server

23-2

23.3

Using OCI XML DB Functions

23-2

23.4

OCI Client Access to Binary XML

23-3

23.4.1

Accessing XML Data from an OCI Application

23-4

23.4.2

Repository Context

23-4

23.4.3

Create Repository Context from a Dedicated OCI Connection

23-4

23.4.4

Create Repository Context from a Connection Pool

23-5

23.4.5

About Associating Repository Context with a Data Connection

23-5

23.4.6

About Setting XMLType Encoding Format Preference

23-6

23.4.7

Example of Using a Connection Pool

23-6

xxiii

24

Using the Object Type Translator with OCI
24.1

What Is the Object Type Translator?

24-1

24.1.1

About Creating Types in the Database

24-3

24.1.2

About Invoking OTT

24-4

24.2

24.1.2.1

Command Line

24-4

24.1.2.2

Configuration File

24-4

24.1.2.3

INTYPE File

24-5

OTT Command Line

24.2.1

OTT Command-Line Invocation Example

24-5
24-5

24.2.1.1

OTT

24-6

24.2.1.2

USERID

24-6

24.2.1.3

INTYPE

24-6

24.2.1.4

OUTTYPE

24-6

24.2.1.5

CODE

24-7

24.2.1.6

HFILE

24-7

24.2.1.7

INITFILE

24-7

24.3

Intype File

24-8

24.4

OTT Data Type Mappings

24-9

24.4.1

About Mapping Object Data Types to C

24-10

24.4.2

OTT Type Mapping Example

24-12

24.4.3

Null Indicator Structs

24-14

24.4.4

OTT Support for Type Inheritance

24-15

24.4.4.1

Substitutable Object Attributes

24-17

24.5

Outtype File

24-18

24.6

About Using OTT with OCI Applications

24-19

24.6.1

About Accessing and Manipulating Objects with OCI

24-20

24.6.2

Calling the Initialization Function

24-21

24.6.3

Tasks of the Initialization Function

24-23

24.7

OTT Reference

24-23

24.7.1

OTT Command-Line Syntax

24-24

24.7.2

OTT Parameters

24-25

24.7.2.1

USERID

24-26

24.7.2.2

INTYPE

24-26

24.7.2.3

OUTTYPE

24-27

24.7.2.4

CODE

24-27

24.7.2.5

INITFILE

24-27

24.7.2.6

INITFUNC

24-28

24.7.2.7

HFILE

24-28

24.7.2.8

CONFIG

24-28

24.7.2.9

ERRTYPE

24-28

xxiv

24.7.2.10

CASE

24-29

24.7.2.11

SCHEMA_NAMES

24-29

24.7.2.12

TRANSITIVE

24-30

24.7.2.13

URL

24-30

24.7.3

Where OTT Parameters Can Appear

24-30

24.7.4

Structure of the Intype File

24-31

24.7.4.1

24-31

24.7.5

Nested Included File Generation

24-32

24.7.6

SCHEMA_NAMES Usage

24-34

24.7.6.1

25

Intype File Type Specifications

Example: Schema_Names Usage

24-35

24.7.7

Default Name Mapping

24-36

24.7.8

OTT Restriction on File Name Comparison

24-37

24.7.9

OTT Command on Microsoft Windows

24-38

Oracle Database Access C API
25.1

Introduction to the Relational Functions

25-1

25.1.1

Conventions for OCI Functions

25-1

25.1.2

Purpose

25-1

25.1.3

Syntax

25-2

25.1.4

Parameters

25-2

25.1.5

Comments

25-2

25.1.6

Returns

25-2

25.1.7

Example

25-2

25.1.8

Related Functions

25-2

25.1.9

About Calling OCI Functions

25-2

25.1.10
25.2

Server Round-Trips for LOB Functions

Connect, Authorize, and Initialize Functions

25-3
25-3

25.2.1

OCIAppCtxClearAll()

25-4

25.2.2

OCIAppCtxSet()

25-5

25.2.3

OCIConnectionPoolCreate()

25-6

25.2.4

OCIConnectionPoolDestroy()

25-8

25.2.5

OCIDBShutdown()

25-9

25.2.6

OCIDBStartup()

25-10

25.2.7

OCIEnvCreate()

25-11

25.2.8

OCIEnvNlsCreate()

25-15

25.2.9

OCILogoff()

25-19

25.2.10

OCILogon()

25-20

25.2.11

OCILogon2()

25-21

25.2.12

OCIRequestDisableReplay()

25-24

25.2.13

OCIServerAttach()

25-25

xxv

25.2.14

OCIServerDetach()

25-27

25.2.15

OCISessionBegin()

25-28

25.2.16

OCISessionEnd()

25-31

25.2.17

OCISessionGet()

25-32

25.2.18

OCISessionPoolCreate()

25-39

25.2.19

OCISessionPoolDestroy()

25-42

25.2.20

OCISessionRelease()

25-43

25.2.21

OCITerminate()

25-44

25.3

Handle and Descriptor Functions

25.3.1

OCIArrayDescriptorAlloc()

25-45

25.3.2

OCIArrayDescriptorFree()

25-47

25.3.3

OCIAttrGet()

25-48

25.3.4

OCIAttrSet()

25-49

25.3.5

OCIDescriptorAlloc()

25-50

25.3.6

OCIDescriptorFree()

25-53

25.3.7

OCIHandleAlloc()

25-53

25.3.8

OCIHandleFree()

25-54

25.3.9

OCIParamGet()

25-55

25.3.10
25.4

26

25-45

OCIParamSet()

Bind, Define, and Describe Functions

25-57
25-58

25.4.1

OCIBindArrayOfStruct()

25-59

25.4.2

OCIBindByName()

25-60

25.4.3

OCIBindByName2()

25-65

25.4.4

OCIBindByPos()

25-71

25.4.5

OCIBindByPos2()

25-76

25.4.6

OCIBindDynamic()

25-81

25.4.7

OCIBindObject()

25-84

25.4.8

OCIDefineArrayOfStruct()

25-87

25.4.9

OCIDefineByPos()

25-88

25.4.10

OCIDefineByPos2()

25-92

25.4.11

OCIDefineDynamic()

25-97

25.4.12

OCIDefineObject()

25-100

25.4.13

OCIDescribeAny()

25-102

25.4.14

OCIStmtGetBindInfo()

25-104

More Oracle Database Access C API
26.1

Introduction to the Relational Functions

26.1.1
26.2

Conventions for OCI Functions

Statement Functions

26.2.1

OCIStmtExecute()

26-1
26-2
26-2
26-2

xxvi

26.2.2

OCIStmtFetch2()

26-5

26.2.3

OCIStmtGetNextResult()

26-7

26.2.4

OCIStmtGetPieceInfo()

26-9

26.2.5

OCIStmtPrepare2()

26-10

26.2.6

OCIStmtRelease()

26-12

26.2.7

OCIStmtSetPieceInfo()

26-13

26.3

LOB Functions

26-14

26.3.1

OCIDurationBegin()

26-17

26.3.2

OCIDurationEnd()

26-18

26.3.3

OCILobAppend()

26-19

26.3.4

OCILobArrayRead()

26-20

26.3.5

OCILobArrayWrite()

26-24

26.3.6

OCILobAssign()

26-28

26.3.7

OCILobCharSetForm()

26-30

26.3.8

OCILobCharSetId()

26-31

26.3.9

OCILobClose()

26-32

26.3.10

OCILobCopy2()

26-33

26.3.11

OCILobCreateTemporary()

26-35

26.3.12

OCILobErase2()

26-37

26.3.13

OCILobFileClose()

26-38

26.3.14

OCILobFileCloseAll()

26-40

26.3.15

OCILobFileExists()

26-40

26.3.16

OCILobFileGetName()

26-42

26.3.17

OCILobFileIsOpen()

26-43

26.3.18

OCILobFileOpen()

26-44

26.3.19

OCILobFileSetName()

26-45

26.3.20

OCILobFreeTemporary()

26-47

26.3.21

OCILobGetChunkSize()

26-48

26.3.22

OCILobGetContentType()

26-49

26.3.23

OCILobGetLength2()

26-50

26.3.24

OCILobGetOptions()

26-52

26.3.25

OCILobGetStorageLimit()

26-53

26.3.26

OCILobIsEqual()

26-54

26.3.27

OCILobIsOpen()

26-55

26.3.28

OCILobIsTemporary()

26-56

26.3.29

OCILobLoadFromFile2()

26-57

26.3.30

OCILobLocatorAssign()

26-59

26.3.31

OCILobLocatorIsInit()

26-60

26.3.32

OCILobOpen()

26-62

26.3.33

OCILobRead2()

26-63

26.3.34

OCILobSetContentType()

26-67

xxvii

26.3.35

OCILobSetOptions()

26-68

26.3.36

OCILobTrim2()

26-70

26.3.37

OCILobWrite2()

26-71

26.3.38

OCILobWriteAppend2()

26-75

26.4

Streams Advanced Queuing and Publish-Subscribe Functions

26-78

26.4.1

OCIAQDeq()

26-79

26.4.2

OCIAQDeqArray()

26-81

26.4.3

OCIAQEnq()

26-83

26.4.4

OCIAQEnqArray()

26-85

26.4.5

OCIAQListen2()

26-87

26.4.6

OCISubscriptionDisable()

26-89

26.4.7

OCISubscriptionEnable()

26-90

26.4.8

OCISubscriptionPost()

26-91

26.4.9

OCISubscriptionRegister()

26-93

26.4.10
26.5

OCISubscriptionUnRegister()

Direct Path Loading Functions

26-95
26-96

26.5.1

OCIDirPathAbort()

26-97

26.5.2

OCIDirPathColArrayEntryGet()

26-97

26.5.3

OCIDirPathColArrayEntrySet()

26-99

26.5.4

OCIDirPathColArrayReset()

26-100

26.5.5

OCIDirPathColArrayRowGet()

26-101

26.5.6

OCIDirPathColArrayToStream()

26-102

26.5.7

OCIDirPathDataSave()

26-104

26.5.8

OCIDirPathFinish()

26-105

26.5.9

OCIDirPathFlushRow()

26-105

26.5.10

OCIDirPathLoadStream()

26-106

26.5.11

OCIDirPathPrepare()

26-107

26.5.12

OCIDirPathStreamReset()

26-109

26.6

Thread Management Functions

26-109

26.6.1

OCIThreadClose()

26-111

26.6.2

OCIThreadCreate()

26-111

26.6.3

OCIThreadHandleGet()

26-112

26.6.4

OCIThreadHndDestroy()

26-113

26.6.5

OCIThreadHndInit()

26-114

26.6.6

OCIThreadIdDestroy()

26-115

26.6.7

OCIThreadIdGet()

26-116

26.6.8

OCIThreadIdInit()

26-117

26.6.9

OCIThreadIdNull()

26-118

26.6.10

OCIThreadIdSame()

26-119

26.6.11

OCIThreadIdSet()

26-120

26.6.12

OCIThreadIdSetNull()

26-121

xxviii

26.6.13

OCIThreadInit()

26-122

26.6.14

OCIThreadIsMulti()

26-122

26.6.15

OCIThreadJoin()

26-123

26.6.16

OCIThreadKeyDestroy()

26-124

26.6.17

OCIThreadKeyGet()

26-125

26.6.18

OCIThreadKeyInit()

26-126

26.6.19

OCIThreadKeySet()

26-127

26.6.20

OCIThreadMutexAcquire()

26-127

26.6.21

OCIThreadMutexDestroy()

26-128

26.6.22

OCIThreadMutexInit()

26-129

26.6.23

OCIThreadMutexRelease()

26-130

26.6.24

OCIThreadProcessInit()

26-131

26.6.25

OCIThreadTerm()

26-132

26.7

Transaction Functions

26-132

26.7.1

OCITransCommit()

26-133

26.7.2

OCITransDetach()

26-135

26.7.3

OCITransForget()

26-136

26.7.4

OCITransMultiPrepare()

26-137

26.7.5

OCITransPrepare()

26-138

26.7.6

OCITransRollback()

26-139

26.7.7

OCITransStart()

26-140

26.8

Sharding Functions

26-145

26.8.1

OCIShardingKeyColumnAdd()

26-146

26.8.2

OCIShardingKeyReset()

26-148

26.8.3

OCIShardInstancesGet()

26-148

26.9

Miscellaneous Functions

26-151

26.9.1

OCIBreak()

26-152

26.9.2

OCIClientVersion()

26-153

26.9.3

OCIErrorGet()

26-154

26.9.4

OCILdaToSvcCtx()

26-157

26.9.5

OCIPasswordChange()

26-158

26.9.6

OCIPing()

26-160

26.9.7

OCIReset()

26-161

26.9.8

OCIRowidToChar()

26-161

26.9.9

OCIServerRelease()

26-163

26.9.10

OCIServerRelease2()

26-164

26.9.11

OCIServerVersion()

26-165

26.9.12

OCISvcCtxToLda()

26-166

26.9.13

OCIUserCallbackGet()

26-167

26.9.14

OCIUserCallbackRegister()

26-168

xxix

27

OCI Navigational and Type Functions
27.1

Introduction to the Navigational and Type Functions

27-1

27.1.1

Object Types and Lifetimes

27-2

27.1.2

Terminology

27-3

27.1.3

Conventions for OCI Functions

27-3

27.1.4

Return Values

27-3

27.1.5

Navigational Function Return Values

27-4

27.1.6

Server Round-Trips for Cache and Object Functions

27-4

27.1.7

Navigational Function Error Codes

27-4

27.2

OCI Flush or Refresh Functions

27-6

27.2.1

OCICacheFlush()

27-6

27.2.2

OCICacheRefresh()

27-8

27.2.3

OCIObjectFlush()

27-10

27.2.4

OCIObjectRefresh()

27-11

27.3

OCI Mark or Unmark Object and Cache Functions

27-13

27.3.1

OCICacheUnmark()

27-13

27.3.2

OCIObjectMarkDelete()

27-14

27.3.3

OCIObjectMarkDeleteByRef()

27-15

27.3.4

OCIObjectMarkUpdate()

27-16

27.3.5

OCIObjectUnmark()

27-18

27.3.6

OCIObjectUnmarkByRef()

27-19

27.4

OCI Get Object Status Functions

27-20

27.4.1

OCIObjectExists()

27-20

27.4.2

OCIObjectGetProperty()

27-21

27.4.3

OCIObjectIsDirty()

27-24

27.4.4

OCIObjectIsLocked()

27-25

27.5

OCI Miscellaneous Object Functions

27-26

27.5.1

OCIObjectCopy()

27-27

27.5.2

OCIObjectGetAttr()

27-29

27.5.3

OCIObjectGetInd()

27-31

27.5.4

OCIObjectGetObjectRef()

27-32

27.5.5

OCIObjectGetTypeRef()

27-33

27.5.6

OCIObjectLock()

27-34

27.5.7

OCIObjectLockNoWait()

27-35

27.5.8

OCIObjectNew()

27-36

27.5.9

OCIObjectSetAttr()

27-40

27.6

OCI Pin, Unpin, and Free Functions

27-42

27.6.1

OCICacheFree()

27-42

27.6.2

OCICacheUnpin()

27-44

27.6.3

OCIObjectArrayPin()

27-45

xxx

27.6.4

OCIObjectFree()

27-46

27.6.5

OCIObjectPin()

27-47

27.6.6

OCIObjectPinCountReset()

27-50

27.6.7

OCIObjectPinTable()

27-51

27.6.8

OCIObjectUnpin()

27-53

27.7

28

OCI Type Information Accessor Functions

27-54

27.7.1

OCITypeArrayByName()

27-55

27.7.2

OCITypeArrayByFullName()

27-57

27.7.3

OCITypeArrayByRef()

27-60

27.7.4

OCITypeByFullName()

27-62

27.7.5

OCITypeByName()

27-64

27.7.6

OCITypeByRef()

27-67

27.7.7

OCITypePackage()

27-68

OCI Data Type Mapping and Manipulation Functions
28.1

Introduction to Data Type Mapping and Manipulation Functions

28-1

28.1.1

Conventions for OCI Functions

28-2

28.1.2

Returns

28-2

28.1.3

Data Type Mapping and Manipulation Function Return Values

28-2

28.1.4

Functions Returning Other Values

28-2

28.1.5

Server Round-Trips for Data Type Mapping and Manipulation
Functions

28-3

Examples

28-3

28.1.6
28.2

OCI Collection and Iterator Functions

28-3

28.2.1

OCICollAppend()

28-4

28.2.2

OCICollAssign()

28-5

28.2.3

OCICollAssignElem()

28-6

28.2.4

OCICollGetElem()

28-7

28.2.5

OCICollGetElemArray()

28-10

28.2.6

OCICollIsLocator()

28-12

28.2.7

OCICollMax()

28-13

28.2.8

OCICollSize()

28-14

28.2.9

OCICollTrim()

28-15

28.2.10

OCIIterCreate()

28-16

28.2.11

OCIIterDelete()

28-18

28.2.12

OCIIterGetCurrent()

28-19

28.2.13

OCIIterInit()

28-20

28.2.14

OCIIterNext()

28-22

28.2.15

OCIIterPrev()

28-23

28.3

OCI Date, Datetime, and Interval Functions

28.3.1

OCIDateAddDays()

28-25
28-27

xxxi

28.3.2

OCIDateAddMonths()

28-28

28.3.3

OCIDateAssign()

28-29

28.3.4

OCIDateCheck()

28-29

28.3.5

OCIDateCompare()

28-31

28.3.6

OCIDateDaysBetween()

28-31

28.3.7

OCIDateFromText()

28-32

28.3.8

OCIDateGetDate()

28-33

28.3.9

OCIDateGetTime()

28-34

28.3.10

OCIDateLastDay()

28-35

28.3.11

OCIDateNextDay()

28-36

28.3.12

OCIDateSetDate()

28-37

28.3.13

OCIDateSetTime()

28-37

28.3.14

OCIDateSysDate()

28-38

28.3.15

OCIDateTimeAssign()

28-39

28.3.16

OCIDateTimeCheck()

28-39

28.3.17

OCIDateTimeCompare()

28-41

28.3.18

OCIDateTimeConstruct()

28-42

28.3.19

OCIDateTimeConvert()

28-43

28.3.20

OCIDateTimeFromArray()

28-44

28.3.21

OCIDateTimeFromText()

28-45

28.3.22

OCIDateTimeGetDate()

28-47

28.3.23

OCIDateTimeGetTime()

28-48

28.3.24

OCIDateTimeGetTimeZoneName()

28-49

28.3.25

OCIDateTimeGetTimeZoneOffset()

28-50

28.3.26

OCIDateTimeIntervalAdd()

28-51

28.3.27

OCIDateTimeIntervalSub()

28-51

28.3.28

OCIDateTimeSubtract()

28-52

28.3.29

OCIDateTimeSysTimeStamp()

28-53

28.3.30

OCIDateTimeToArray()

28-54

28.3.31

OCIDateTimeToText()

28-55

28.3.32

OCIDateToText()

28-56

28.3.33

OCIDateZoneToZone()

28-58

28.3.34

OCIIntervalAdd()

28-59

28.3.35

OCIIntervalAssign()

28-60

28.3.36

OCIIntervalCheck()

28-60

28.3.37

OCIIntervalCompare()

28-62

28.3.38

OCIIntervalDivide()

28-63

28.3.39

OCIIntervalFromNumber()

28-63

28.3.40

OCIIntervalFromText()

28-64

28.3.41

OCIIntervalFromTZ()

28-65

28.3.42

OCIIntervalGetDaySecond()

28-66

xxxii

28.3.43

OCIIntervalGetYearMonth()

28-67

28.3.44

OCIIntervalMultiply()

28-68

28.3.45

OCIIntervalSetDaySecond()

28-69

28.3.46

OCIIntervalSetYearMonth()

28-70

28.3.47

OCIIntervalSubtract()

28-71

28.3.48

OCIIntervalToNumber()

28-72

28.3.49

OCIIntervalToText()

28-72

28.4

OCI NUMBER Functions

28-74

28.4.1

OCINumberAbs()

28-75

28.4.2

OCINumberAdd()

28-76

28.4.3

OCINumberArcCos()

28-77

28.4.4

OCINumberArcSin()

28-77

28.4.5

OCINumberArcTan()

28-78

28.4.6

OCINumberArcTan2()

28-79

28.4.7

OCINumberAssign()

28-79

28.4.8

OCINumberCeil()

28-80

28.4.9

OCINumberCmp()

28-81

28.4.10

OCINumberCos()

28-82

28.4.11

OCINumberDec()

28-82

28.4.12

OCINumberDiv()

28-83

28.4.13

OCINumberExp()

28-84

28.4.14

OCINumberFloor()

28-85

28.4.15

OCINumberFromInt()

28-85

28.4.16

OCINumberFromReal()

28-86

28.4.17

OCINumberFromText()

28-87

28.4.18

OCINumberHypCos()

28-88

28.4.19

OCINumberHypSin()

28-89

28.4.20

OCINumberHypTan()

28-90

28.4.21

OCINumberInc()

28-91

28.4.22

OCINumberIntPower()

28-91

28.4.23

OCINumberIsInt()

28-92

28.4.24

OCINumberIsZero()

28-93

28.4.25

OCINumberLn()

28-93

28.4.26

OCINumberLog()

28-94

28.4.27

OCINumberMod()

28-95

28.4.28

OCINumberMul()

28-96

28.4.29

OCINumberNeg()

28-97

28.4.30

OCINumberPower()

28-97

28.4.31

OCINumberPrec()

28-98

28.4.32

OCINumberRound()

28-99

28.4.33

OCINumberSetPi()

28-100

xxxiii

28.4.34

OCINumberSetZero()

28-100

28.4.35

OCINumberShift()

28-101

28.4.36

OCINumberSign()

28-101

28.4.37

OCINumberSin()

28-102

28.4.38

OCINumberSqrt()

28-103

28.4.39

OCINumberSub()

28-104

28.4.40

OCINumberTan()

28-104

28.4.41

OCINumberToInt()

28-105

28.4.42

OCINumberToReal()

28-106

28.4.43

OCINumberToRealArray()

28-107

28.4.44

OCINumberToText()

28-108

28.4.45

OCINumberTrunc()

28-109

28.5

OCI Raw Functions

28-110

28.5.1

OCIRawAllocSize()

28-110

28.5.2

OCIRawAssignBytes()

28-111

28.5.3

OCIRawAssignRaw()

28-112

28.5.4

OCIRawPtr()

28-113

28.5.5

OCIRawResize()

28-114

28.5.6

OCIRawSize()

28-115

28.6

OCI REF Functions

28-116

28.6.1

OCIRefAssign()

28-116

28.6.2

OCIRefClear()

28-117

28.6.3

OCIRefFromHex()

28-118

28.6.4

OCIRefHexSize()

28-119

28.6.5

OCIRefIsEqual()

28-120

28.6.6

OCIRefIsNull()

28-121

28.6.7

OCIRefToHex()

28-122

OCI String Functions

28-124

28.7

28.7.1

OCIStringAllocSize()

28-124

28.7.2

OCIStringAssign()

28-125

28.7.3

OCIStringAssignText()

28-126

28.7.4

OCIStringPtr()

28-127

28.7.5

OCIStringResize()

28-128

28.7.6

OCIStringSize()

28-129

28.8

OCI Table Functions

28-130

28.8.1

OCITableDelete()

28-130

28.8.2

OCITableExists()

28-131

28.8.3

OCITableFirst()

28-132

28.8.4

OCITableLast()

28-134

28.8.5

OCITableNext()

28-135

28.8.6

OCITablePrev()

28-136

xxxiv

28.8.7

29

OCITableSize()

28-137

OCI Cartridge Functions
29.1

Introduction to External Procedure and Cartridge Services Functions

29.1.1
29.2

Conventions for OCI Functions

Cartridge Services — OCI External Procedures

29-1
29-1
29-2

29.2.1

OCIExtProcAllocCallMemory()

29-2

29.2.2

OCIExtProcGetEnv()

29-3

29.2.3

OCIExtProcRaiseExcp()

29-4

29.2.4

OCIExtProcRaiseExcpWithMsg()

29-5

Cartridge Services — Memory Services

29-6

29.3

29.3.1

OCIDurationBegin()

29-7

29.3.2

OCIDurationEnd()

29-8

29.3.3

OCIMemoryAlloc()

29-8

29.3.4

OCIMemoryFree()

29-9

29.3.5

OCIMemoryResize()

29.4

Cartridge Services — Maintaining Context

29-10
29-11

29.4.1

OCIContextClearValue()

29-11

29.4.2

OCIContextGenerateKey()

29-12

29.4.3

OCIContextGetValue()

29-13

29.4.4

OCIContextSetValue()

29-13

29.5

Cartridge Services — Parameter Manager Interface

29-15

29.5.1

OCIExtractFromFile()

29-15

29.5.2

OCIExtractFromList()

29-16

29.5.3

OCIExtractFromStr()

29-17

29.5.4

OCIExtractInit()

29-18

29.5.5

OCIExtractReset()

29-19

29.5.6

OCIExtractSetKey()

29-20

29.5.7

OCIExtractSetNumKeys()

29-21

29.5.8

OCIExtractTerm()

29-22

29.5.9

OCIExtractToBool()

29-22

29.5.10

OCIExtractToInt()

29-23

29.5.11

OCIExtractToList()

29-24

29.5.12

OCIExtractToOCINum()

29-25

29.5.13

OCIExtractToStr()

29-25

29.6

Cartridge Services — File I/O Interface

29-26

29.6.1

OCIFileClose()

29-27

29.6.2

OCIFileExists()

29-28

29.6.3

OCIFileFlush()

29-29

29.6.4

OCIFileGetLength()

29-29

xxxv

29.6.5

OCIFileInit()

29-30

29.6.6

OCIFileOpen()

29-31

29.6.7

OCIFileRead()

29-32

29.6.8

OCIFileSeek()

29-33

29.6.9

OCIFileTerm()

29-34

29.6.10
29.7

30

OCIFileWrite()

Cartridge Services — String Formatting Interface

29-34
29-35

29.7.1

OCIFormatInit()

29-36

29.7.2

OCIFormatString()

29-36

29.7.3

OCIFormatTerm()

29-41

OCI Any Type and Data Functions
30.1

Introduction to Any Type and Data Interfaces

30.1.1
30.2

Conventions for OCI Functions

OCI Type Interface Functions

30-1
30-1
30-2

30.2.1

OCITypeAddAttr()

30-2

30.2.2

OCITypeBeginCreate()

30-3

30.2.3

OCITypeEndCreate()

30-5

30.2.4

OCITypeSetBuiltin()

30-5

30.2.5

OCITypeSetCollection()

30-6

30.3

OCI Any Data Interface Functions

30-7

30.3.1

OCIAnyDataAccess()

30-8

30.3.2

OCIAnyDataAttrGet()

30-9

30.3.3

OCIAnyDataAttrSet()

30-11

30.3.4

OCIAnyDataBeginCreate()

30-13

30.3.5

OCIAnyDataCollAddElem()

30-15

30.3.6

OCIAnyDataCollGetElem()

30-16

30.3.7

OCIAnyDataConvert()

30-18

30.3.8

OCIAnyDataDestroy()

30-20

30.3.9

OCIAnyDataEndCreate()

30-20

30.3.10

OCIAnyDataGetCurrAttrNum()

30-21

30.3.11

OCIAnyDataGetType()

30-21

30.3.12

OCIAnyDataIsNull()

30-22

30.3.13

OCIAnyDataTypeCodeToSqlt()

30-23

OCI Any Data Set Interface Functions

30-24

30.4

30.4.1

OCIAnyDataSetAddInstance()

30-24

30.4.2

OCIAnyDataSetBeginCreate()

30-25

30.4.3

OCIAnyDataSetDestroy()

30-26

30.4.4

OCIAnyDataSetEndCreate()

30-27

30.4.5

OCIAnyDataSetGetCount()

30-28

xxxvi

31

30.4.6

OCIAnyDataSetGetInstance()

30-28

30.4.7

OCIAnyDataSetGetType()

30-29

OCI Globalization Support Functions
31.1

Introduction to Globalization Support in OCI

31.1.1
31.2

Conventions for OCI Functions

OCI Locale Functions

31-1
31-1
31-2

31.2.1

OCINlsCharSetIdToName()

31-2

31.2.2

OCINlsCharSetNameToId()

31-3

31.2.3

OCINlsEnvironmentVariableGet()

31-4

31.2.4

OCINlsGetInfo()

31-5

31.2.5

OCINlsNumericInfoGet()

31-7

OCI Locale-Mapping Function

31-8

31.3

31.3.1
31.4

OCINlsNameMap()

OCI String Manipulation Functions

31-9
31-10

31.4.1

OCIMultiByteInSizeToWideChar()

31-12

31.4.2

OCIMultiByteStrCaseConversion()

31-13

31.4.3

OCIMultiByteStrcat()

31-14

31.4.4

OCIMultiByteStrcmp()

31-14

31.4.5

OCIMultiByteStrcpy()

31-16

31.4.6

OCIMultiByteStrlen()

31-16

31.4.7

OCIMultiByteStrncat()

31-17

31.4.8

OCIMultiByteStrncmp()

31-18

31.4.9

OCIMultiByteStrncpy()

31-19

31.4.10

OCIMultiByteStrnDisplayLength()

31-20

31.4.11

OCIMultiByteToWideChar()

31-21

31.4.12

OCIWideCharInSizeToMultiByte()

31-22

31.4.13

OCIWideCharMultiByteLength()

31-23

31.4.14

OCIWideCharStrCaseConversion()

31-23

31.4.15

OCIWideCharStrcat()

31-24

31.4.16

OCIWideCharStrchr()

31-25

31.4.17

OCIWideCharStrcmp()

31-26

31.4.18

OCIWideCharStrcpy()

31-27

31.4.19

OCIWideCharStrlen()

31-27

31.4.20

OCIWideCharStrncat()

31-28

31.4.21

OCIWideCharStrncmp()

31-29

31.4.22

OCIWideCharStrncpy()

31-30

31.4.23

OCIWideCharStrrchr()

31-31

31.4.24

OCIWideCharToLower()

31-32

31.4.25

OCIWideCharToMultiByte()

31-33

xxxvii

31.4.26
31.5

OCI Character Classification Functions

31-34

OCIWideCharIsAlnum()

31-35

31.5.2

OCIWideCharIsAlpha()

31-35

31.5.3

OCIWideCharIsCntrl()

31-36

31.5.4

OCIWideCharIsDigit()

31-36

31.5.5

OCIWideCharIsGraph()

31-37

31.5.6

OCIWideCharIsLower()

31-37

31.5.7

OCIWideCharIsPrint()

31-38

31.5.8

OCIWideCharIsPunct()

31-38

31.5.9

OCIWideCharIsSingleByte()

31-39

31.5.10

OCIWideCharIsSpace()

31-39

31.5.11

OCIWideCharIsUpper()

31-40

31.5.12

OCIWideCharIsXdigit()

31-40

OCI Character Set Conversion Functions

31-41

31.6.1

OCICharSetConversionIsReplacementUsed()

31-41

31.6.2

OCICharSetToUnicode()

31-42

31.6.3

OCINlsCharSetConvert()

31-43

31.6.4

OCIUnicodeToCharSet()

31-44

31.7

OCI Messaging Functions

31-45

31.7.1

OCIMessageClose()

31-46

31.7.2

OCIMessageGet()

31-47

31.7.3

OCIMessageOpen()

31-47

OCI XML DB Functions
32.1

Introduction to XML DB Support in OCI

32-1

32.1.1

Conventions for OCI Functions

32-1

32.1.2

Returns

32-1

32.2

33

31-33

31.5.1

31.6

32

OCIWideCharToUpper()

OCI XML DB Functions

32-2

32.2.1

OCIBinXmlCreateReposCtxFromConn()

32-2

32.2.2

OCIBinXmlCreateReposCtxFromCPool()

32-3

32.2.3

OCIBinXmlSetFormatPref()

32-4

32.2.4

OCIBinXmlSetReposCtxForConn()

32-4

32.2.5

OCIXmlDbFreeXmlCtx()

32-5

32.2.6

OCIXmlDbInitXmlCtx()

32-5

Oracle ODBC Driver

xxxviii

34

Introduction to the OCI Interface for XStream
34.1

34-1

34.1.1

XStream Out

34-1

34.1.2

XStream In

34-2

34.1.3

Position Order and LCR Streams

34-2

34.1.4

XStream and Character Sets

34-2

34.2

35

About the XStream Interface

Handler and Descriptor Attributes

34-3

34.2.1

Conventions

34-3

34.2.2

Server Handle Attributes

34-3

34.2.2.1

OCI_ATTR_XSTREAM_ACK_INTERVAL

34-3

34.2.2.2

OCI_ATTR_XSTREAM_IDLE_TIMEOUT

34-4

OCI XStream Functions
35.1

About Using the XStream Interface

35.1.1

XStream Out

35-1
35-2

35.1.1.1

LCR Streams

35-2

35.1.1.2

The Processed Low Position and Restart Considerations

35-3

35.1.2

XStream In

35-3

35.1.2.1

Processed Low Position and Restart Ability

35-3

35.1.2.2

Stream Position

35-4

Security of XStreams

35-4

35.2

Introduction to XStream Functions

35-5

35.3

OCI XStream Functions

35-5

35.1.3

35.3.1

OCILCRAttributesGet()

35-7

35.3.2

OCILCRAttributesSet()

35-9

35.3.3

OCILCRComparePosition()

35-10

35.3.4

OCILCRConvertPosition()

35-11

35.3.5

OCILCRFree()

35-12

35.3.6

OCILCRDDLInfoGet()

35-13

35.3.7

OCILCRHeaderGet()

35-15

35.3.8

OCILCRRowStmtGet()

35-17

35.3.9

OCILCRRowStmtWithBindVarGet()

35-18

35.3.10

OCILCRNew()

35-20

35.3.11

OCILCRRowColumnInfoGet()

35-21

35.3.12

OCILCRRowColumnInfoSet()

35-24

35.3.13

OCILCRDDLInfoSet()

35-26

35.3.14

OCILCRGetLCRIDVersion()

35-28

35.3.15

OCILCRHeaderSet()

35-29

35.3.16

OCILCRLobInfoGet()

35-32

35.3.17

OCILCRLobInfoSet()

35-33

xxxix

36

35.3.18

OCILCRSCNsFromPosition()

35-34

35.3.19

OCILCRSCNToPosition()

35-35

35.3.20

OCILCRScnToPosition2()

35-36

35.3.21

OCILCRWhereClauseGet()

35-37

35.3.22

OCILCRWhereClauseWithBindVarGet()

35-38

35.3.23

OCIXStreamInAttach()

35-40

35.3.24

OCIXStreamInDetach()

35-41

35.3.25

OCIXStreamInLCRSend()

35-42

35.3.26

OCIXStreamInLCRCallbackSend()

35-43

35.3.27

OCIXStreamInProcessedLWMGet()

35-47

35.3.28

OCIXStreamInErrorGet()

35-49

35.3.29

OCIXStreamInFlush()

35-50

35.3.30

OCIXStreamInChunkSend()

35-50

35.3.31

OCIXStreamInCommit()

35-54

35.3.32

OCIXStreamInSessionSet()

35-55

35.3.33

OCIXStreamOutAttach()

35-56

35.3.34

OCIXStreamOutDetach()

35-57

35.3.35

OCIXStreamOutLCRReceive()

35-58

35.3.36

OCIXStreamOutLCRCallbackReceive()

35-59

35.3.37

OCIXStreamOutProcessedLWMSet()

35-64

35.3.38

OCIXStreamOutChunkReceive()

35-65

35.3.39

OCIXStreamOutGetNextChunk()

35-68

35.3.40

OCIXStreamOutSessionSet()

35-71

OCI SODA Functions
36.1

Introduction to OCI SODA Functions

36-1

36.2

OCI SODA Functions

36-1

36.2.1

OCISodaCollCreate()

36-2

36.2.2

OCISodaCollCreateWithMetadata()

36-3

36.2.3

OCISodaCollOpen()

36-4

36.2.4

OCISodaCollList()

36-6

36.2.5

OCISodaCollGetNext()

36-7

36.2.6

OCISodaCollDrop()

36-8

36.2.7

OCISodaDocCreate()

36-9

36.2.8

OCISodaDocCreateWithKey()

36-11

36.2.9

OCISodaDocCreateWithKeyAndMType()

36-13

36.2.10

OCISodaFindOneWithKey()

36-15

36.2.11

OCISodaInsert()

36-16

36.2.12

OCISodaInsertAndGet()

36-18

36.2.13

OCISodaInsertAndGetWithCtnt()

36-20

xl

A

36.2.14

OCISodaInsertWithCtnt()

36-22

36.2.15

OCISodaRemoveOneWithKey()

36-24

36.2.16

OCISodaReplOneAndGetWithKey()

36-25

36.2.17

OCISodaReplOneWithKey()

36-27

Handle and Descriptor Attributes
A.1

Conventions

A-2

A.2

Environment Handle Attributes

A-2

A.3

Error Handle Attributes

A-9

A.4

Service Context Handle Attributes

A-10

A.5

Server Handle Attributes

A-15

A.5.1

Authentication Information Handle Attributes

A-20

A.5.2

User Session Handle Attributes

A-21

A.6

Administration Handle Attributes

A-33

A.7

Connection Pool Handle Attributes

A-34

A.7.1

Session Pool Handle Attributes

A-35

A.8

Transaction Handle Attributes

A-39

A.9

Statement Handle Attributes

A-40

A.10

Bind Handle Attributes

A-50

A.11

Define Handle Attributes

A-54

A.12

Describe Handle Attributes

A-56

A.13

Parameter Descriptor Attributes

A-58

A.14

Shard Instance Descriptor Attributes

A-58

A.15

SODA Document Handle Attributes

A-59

A.16

SODA Collection Handle Attributes

A-61

A.17

LOB Descriptor and LOB Locator Attributes

A-70

A.18

Complex Object Attributes

A-71

A.18.1

Complex Object Retrieval Handle Attributes

A-71

A.18.2

Complex Object Retrieval Descriptor Attributes

A-72

A.19

Streams Advanced Queuing Descriptor Attributes

A-72

A.19.1

OCIAQEnqOptions Descriptor Attributes

A-73

A.19.2

OCIAQDeqOptions Descriptor Attributes

A-74

A.19.3

OCIAQMsgProperties Descriptor Attributes

A-78

A.19.4

OCIAQAgent Descriptor Attributes

A-82

A.19.5

OCIServerDNs Descriptor Attributes

A-83

A.20

Subscription Handle Attributes

A-83

A.20.1

Continuous Query Notification Attributes

A-90

A.20.2

Continuous Query Notification Descriptor Attributes

A-91

A.20.3

Notification Descriptor Attributes

A-93

A.20.4

Invalidated Query Attributes

A-94

xli

A.21

Direct Path Loading Handle Attributes

A.21.1

Direct Path Context Handle (OCIDirPathCtx) Attributes

A.21.2

Direct Path Function Context Handle (OCIDirPathFuncCtx) Attributes

A-103

A.21.3

Direct Path Function Column Array Handle (OCIDirPathColArray)
Attributes

A-105

A.21.4

Direct Path Stream Handle (OCIDirPathStream) Attributes

A-106

A.21.5

Direct Path Column Parameter Attributes

A-106

A.21.5.1

About Accessing Column Parameter Attributes

A-96

A-107

A.22

Process Handle Attributes

A-111

A.23

Event Handle Attributes

A-113

B

OCI Demonstration Programs

C

OCI Function Server Round-Trips

D

A-95

C.1

Relational Function Round-Trips

C-2

C.2

LOB Function Round-Trips

C-3

C.3

Object and Cache Function Round-Trips

C-5

C.4

Describe Operation Round-Trips

C-6

C.5

Data Type Mapping and Manipulation Function Round-Trips

C-6

C.6

Any Type and Data Function Round-Trips

C-7

C.7

Other Local Functions

C-7

Getting Started with OCI for Windows
D.1

What Is Included in the OCI Package for Windows?

D-1

D.2

Oracle Directory Structure for Windows

D-2

D.3

Sample OCI Programs for Windows

D-2

D.4

About Compiling OCI Applications for Windows

D-2

D.5

About Linking OCI Applications for Windows

D-3

D.5.1

oci.lib

D-3

D.5.2

Client DLL Loading When Using Load Library()

D-3

D.6

About Running OCI Applications for Windows

D-4

D.7

Oracle XA Library

D-4

D.7.1
D.7.2

About Compiling and Linking an OCI Program with the Oracle XA
Library

D-5

About Using XA Dynamic Registration

D-5

D.7.2.1

Adding an Environmental Variable for the Current Session

D-5

D.7.2.2

About Adding a Registry Variable for All Sessions

D-5

D.7.2.3

Adding a Registry Variable:

D-6

D.7.3

XA and TP Monitor Information

D-6

xlii

D.8

E

About Using the Object Type Translator for Windows

Deprecated OCI Features and Functions
E.1

E.2

E.3

E.4

Deprecated Initialize Functions

E-1

E.1.1

OCIEnvInit()

E-2

E.1.2

OCIInitialize()

E-3

Deprecated Statement Functions

E-6

E.2.1

OCIStmtFetch()

E-6

E.2.2

OCIStmtPrepare()

E-7

Deprecated Lob Functions

E-9

E.3.1

OCILobCopy()

E.3.2

OCILobDisableBuffering()

E-10

E.3.3

OCILobEnableBuffering()

E-11

E.3.4

OCILobErase()

E-12

E.3.5

OCILobFlushBuffer()

E-13

E.3.6

OCILobGetLength()

E-14

E.3.7

OCILobLoadFromFile()

E-15

E.3.8

OCILobRead()

E-15

E.3.9

OCILobTrim()

E-19

E-9

E.3.10

OCILobWrite()

E-20

E.3.11

OCILobWriteAppend()

E-24

Deprecated Streams Advanced Queuing Functions
E.4.1

F

D-6

OCIAQListen()

E-26
E-27

Multithreaded extproc Agent
F.1

F.2

F.3

Why Use the Multithreaded extproc Agent?

F-1

F.1.1

The Challenge of Dedicated Agent Architecture

F-1

F.1.2

The Advantage of Multithreading

F-1

Multithreaded extproc Agent Architecture

F-2

F.2.1

Monitor Thread

F-4

F.2.2

Dispatcher Threads

F-4

F.2.3

Task Threads

F-4

Administering the Multithreaded extproc Agent

F-5

F.3.1

Agent Control Utility (agtctl) Commands

F-5

F.3.2

About Using agtctl in Single-Line Command Mode

F-6

F.3.2.1

Setting Configuration Parameters for a Multithreaded extproc
Agent

F-7

F.3.2.2

Starting a Multithreaded extproc Agent

F-7

F.3.2.3

Shutting Down a Multithreaded extproc Agent

F-7

F.3.2.4

Examining the Value of Configuration Parameters

F-8

xliii

F.3.2.5

Resetting a Configuration Parameter to Its Default Value

F-8

F.3.2.6

Deleting an Entry for a Specific SID from the Control File

F-8

F.3.2.7

Requesting Help

F-9

Using Shell Mode Commands

F-9

F.3.3

F.3.3.1

Example: Setting a Configuration Parameter

F.3.3.2

Example: Starting a Multithreaded extproc Agent

F.3.4

Configuration Parameters for Multithreaded extproc Agent Control

F-9
F-10
F-10

Index

xliv

List of Examples
4-1

Using the OCI_ATTR_USERNAME Attribute to Set the User Name in the Session Handle

4-11

4-2

Returning Describe Information in the Statement Handle Relating to Select-List Items

4-11

4-3

Using the OCILogon2 Call for a Single User Session

4-20

4-4

Enabling a Local User to Serve as a Proxy for Another User

4-22

4-5

Connection String to Use for the Proxy User

4-22

4-6

Preserving Case Sensitivity When Enabling a Local User to Serve as a Proxy for
Another User

4-22

4-7

Preserving Case Sensitivity in the Connection String

4-23

4-8

Using "dilbert[mybert]" in the Connection String

4-23

4-9

Using "dilbert[mybert]"["joe[myjoe]"] in the Connection String

4-23

4-10

Setting the Target User Name

4-23

4-11

Using OCI to Set the OCI_ATTR_PROXY_CLIENT Attribute and the Proxy dilbert

4-23

4-12

Creating and Initializing an OCI Environment

4-24

4-13

Getting Locale Information in OCI

4-43

4-14

Basic String Manipulation in OCI

4-44

4-15

Classifying Characters in OCI

4-45

4-16

Converting Character Sets in OCI

4-46

4-17

Retrieving a Message from a Text Message File

4-47

5-1

OCI Bind and Define Support for 64-Bit Integers

5-13

5-2

Binding 8-Byte Integer Data Types for OUT Binds of a DML Returning Statement

5-14

6-1

Binding Both Input and Output Variables in Nonquery Operations

6-2

Using Batch Error Execution Mode

6-11

6-3

Implicit Describe - Select List Is Available as an Attribute of the Statement Handle

6-13

6-4

Explicit Describe - Returning the Select-List Description for Each Column

6-15

6-5

Access on a Scrollable Cursor

6-21

7-1

Handle Allocation and Binding for Each Placeholder in a SQL Statement

7-6

7-2

Defining a PL/SQL Statement to Be Used in OCI

7-7

7-3

Binding the Placeholder and Executing the Statement to Insert a Single Locator

7-11

7-4

Binding the Placeholder and Executing the Statement to Insert an Array of Locators

7-11

7-5

Allowed: Inserting into C1, C2, and L Columns Up to 8000, 8000, and 2000 ByteSized Bind Variable Data Values, Respectively

7-6

7-14

Allowed: Inserting into C1 and L Columns up to 2000 and 8000 Byte-Sized Bind
Variable Data Values, Respectively

7-7

6-6

7-14

Allowed: Updating C1, C2, and L Columns up to 8000, 8000, and 2000 Byte-Sized
Bind Variable Data Values, Respectively

7-15

xlv

7-8

Allowed: Updating C1, C2, and L Columns up to 2000, 2000, and 8000 Byte-Sized
Bind Variable Data Values, Respectively

7-15

7-9

Allowed: Piecewise, Callback, and Array Insert or Update Operations

7-15

7-10

Not Allowed: Inserting More Than 4000 Bytes into Both LOB and LONG Columns
Using the Same INSERT Statement

7-11

7-15

Allowed: Inserting into the CT3 LOB Column up to 2000 Byte-Sized Bind Variable
Data Values

7-16

7-12

Not Allowed: Binding Any Length Data to a LOB Column in an Insert As Select Operation

7-16

7-13

Defining a Scalar Output Variable Following an Execute and Describe Operation

7-18

7-14

Defining LOBs Before Execution

7-21

7-15

Defining LOBs After Execution

7-21

7-16

Using Multiple Bind and Define Buffers

7-26

7-17

Binding the REF Output Variable in an OCI Application

7-32

7-18

Setting the Client Character Set to OCI_UTF16ID in OCI

7-36

7-19

Insert and Select Operations Using the OCI_ATTR_MAXCHAR_SIZE Attribute

7-41

7-20

Binding and Defining UTF-16 Data

7-42

7-21

Binding the :cursor1 Placeholder to the Statement Handle stm2p as a REF CURSOR

7-44

7-22

Defining a Nested Table (Second Position) as a Statement Handle

7-44

8-1

Initializing the OCI Process in Object Mode

8-2

Using an Explicit Describe to Retrieve Column Data Types for a Table

8-27

8-3

Describing the Stored Procedure

8-29

8-4

Using an Explicit Describe on a Named Object Type

8-30

8-5

Using an Explicit Describe on a Named Collection Type

8-32

8-6

Using a Parameter Descriptor to Retrieve the Data Types, Column Names, and

8-4

Character-Length Semantics

8-34

8-7

Checking for Invisible Columns

8-35

9-1

Implementing Read Callback Functions Using OCILobRead2()

9-16

9-2

Implementing Write Callback Functions Using OCILobWrite2()

9-17

9-3

Using Temporary LOBs

9-22

9-4

Prefetching of LOB Data, Length, and Chunk Size

9-26

10-1

Defining the OCI_ATTR_SERVER_GROUP Attribute to Pass the Server Group Name

10-2

Defining the OCI_ATTR_PROXY_CREDENTIALS Attribute to Specify the
Credentials of the Application Server for Client Authentication

10-3

10-14
10-17

Defining the OCI_ATTR_DISTINGUISHED_NAME Attribute to Pass the
Distinguished Name of the Client

10-17

10-4

Defining the OCI_ATTR_CERTIFICATE Attribute to Pass the Entire X.509 Certificate

10-18

10-5

Defining the OCI_ATTR_INITIAL_CLIENT_ROLES Attribute to Pass the Client Roles

10-18

xlvi

10-6

Defining the OCI_ATTR_CLIENT_IDENTIFIER Attribute to Pass the End-User Identity

10-19

10-7

Defining the OCI_ATTR_PASSWORD Attribute to Pass the Password for Validation

10-19

10-8

OCI Attributes That Let You Specify the External Name and Initial Privileges of a Client

10-19

10-9

Defining the OCI_ATTR_APPCTX_SIZE Attribute to Initialize the Context Array Size
with the Desired Number of Context Attributes

10-10

Using the OCI_ATTR_APPCTX_LIST Attribute to Get a Handle on the Application
Context List Descriptor for the Session

10-11

10-23
10-23

Calling OCIParamGet() to Obtain an Individual Descriptor for the i-th Application
Context Using the Application Context List Descriptor

10-23

10-12

Defining Session Handle Attributes to Set Externally Initialized Context

10-24

10-13

Using the OCI_ATTR_CALL_TIME Attribute to Get the Elapsed Time of the Last
Server Call

10-25

10-14

Using OCISessionBegin() with an Externally Initialized Context

10-26

10-15

Changing the "responsibility" Attribute Value in the CLIENTCONTEXT Namespace

10-29

10-16

Two Ways to Clear Specific Attribute Information in a Client Namespace

10-29

10-17

Clearing All the Context Information in a Specific Client Namespace

10-30

10-18

Calling OCIAttrSet() to Set the OCI_ATTR_EDITION Attribute

10-31

11-1

Example of PL/SQL Fix-Up Callback

11-4

12-1

Event Notification

12-6

12-2

User-Defined Failover Callback Function Definition

12-11

12-3

Failover Callback Registration

12-12

12-4

Failover Callback Unregistration

12-12

12-5

Callback Function That Implements a Failover Strategy

12-13

12-6

Transaction Guard Demo Program

12-17

13-1

Setting QOS Levels, the Notification Grouping Class, Value, and Type, and the
Namespace Specific Context

13-7

13-2

Using AQ Grouping Notification Attributes in an OCI Notification Callback

13-13

13-3

Implementing a Publish Subscription Notification

13-15

13-4

Registering for Notification Using Callback Functions

13-17

13-5

LDAP Registration

13-20

13-6

Enqueue Buffered Messaging

13-30

13-7

Dequeue Buffered Messaging

13-30

14-1

Pseudocode That Describes the Overall Processing of a Typical OCI Call

14-2

Environment Variable Setting for the ORA_OCI_UCBPKG Variable

14-10

14-3

Specifying the pkgNInit() and PkgNEnvCallback() Functions

14-10

14-4

Using pkgNEnvCallback() to Register Entry, Replacement, and Exit Callbacks

14-10

14-5

Registering User Callbacks with the NULL ucbDesc

14-10

14-4

xlvii

14-6

Using the OCIStmtPrepare() Call to Call the Callbacks in Order

15-1

Optimizing Bind and Define Operations on Statements in the Cache

15-5

15-2

Implicit Fetching of ROWIDs

15-8

15-3

DBMS_SQL RETURN_RESULT Subprogram

15-10

15-4

A PL/SQL Stored Procedure to Implicitly Return Result-Sets (Cursors) to the Client

15-10

15-5

An Anonymous PL/SQL Block to Implicitly Return Result-Sets (Cursors) to the Client

15-11

15-6

Using OCIStmtGetNextResult() to Retrieve and Process the Implicit Results
Returned by Either a PL/SQL Stored Procedure or Anonymous Block

14-10

15-11

16-1

Calling OCIDBStartup() to Perform a Database Startup Operation

16-2

16-2

Calling OCIDBShutdown() in OCI_DBSHUTDOWN_FINAL Mode

16-3

16-3

Calling OCIDBShutdown() in OCI_DBSHUTDOWN_ABORT Mode

16-4

19-1

SQL Definition of Standalone Objects

19-5

19-2

SQL Definition of Embedded Objects

19-5

19-3

Pinning an Object

19-12

19-4

Manipulating Object Attributes in OCI

19-14

19-5

Using Complex Object Retrieval in OCI

19-25

19-6

C Representations of Types with Their Corresponding NULL Indicator Structures

19-30

19-7

Creating a New Object for an Object View

19-34

20-1

Manipulating an Attribute of Type OCIDate

20-6

20-2

Manipulating an Attribute of Type OCIDateTime

20-10

20-3

Manipulating an Attribute of Type OCINumber

20-12

20-4

Converting Values in OCINumber Format Returned from OCIDescribeAny() Calls to
Unsigned Integers

20-14

20-5

Manipulating an Attribute of Type OCIString

20-15

20-6

Manipulating an Attribute of Type OCIRaw

20-17

20-7

Using Collection Data Manipulation Functions

20-20

20-8

Using Multilevel Collection Data Manipulation Functions

20-23

20-9

Using REF Manipulation Functions

20-25

20-10

Using Type Interfaces to Construct Object Types

20-27

20-11

Using Type Interfaces to Construct Collection Types

20-28

20-12

Using Special Construction and Access Calls for Improved Performance

20-31

20-13

Method 1 for a Salary Update: Fetch, Convert, and Assign

20-44

20-14

Method 2 for a Salary Update: Fetch and Assign, No Convert

20-44

20-15

Method 3 for a Salary Update: Direct Fetch

20-44

20-16

Using the SQLT_NTY Bind Call Including OCIBindObject()

20-46

20-17

Using the SQLT_NTY Define Call Including OCIDefineObject()

20-47

21-1

Direct Path Programs Must Include the Header Files

21-4

xlviii

21-2

Passing the Handle Type to Allocate the Function Context

21-5

21-3

Explicit Allocation of Direct Path Column Array Handle

21-6

21-4

Explicit Allocation of Direct Path Function Column Array Handle

21-6

21-5

Allocating a Direct Path Stream Handle

21-7

21-6

Data Structures Used in Direct Path Loading Examples

21-9

21-7

Contents of the Header File cdemodp.h

21-9

21-8

Use of OCI Direct Path Interfaces

21-12

21-9

Allocating the Column Array and Stream Handles

21-12

21-10

Getting the Number of Rows and Columns

21-13

21-11

Setting Input Data Fields

21-13

21-12

Resetting the Column Array State

21-13

21-13

Resetting the Stream State

21-13

21-14

Converting Data to Stream Format

21-13

21-15

Loading the Stream

21-13

21-16

Finishing the Direct Path Load Operation

21-13

21-17

Freeing the Direct Path Handles

21-14

21-18

Allocating a Child Column Array for a Column Object

21-20

21-19

Allocating a Child Column Array for a SQL String Column

21-23

21-20

Allocating a Child Column Array for a REF Column

21-27

21-21

Allocating the Column Array for the Object Table

21-31

21-22

Specifying Values for the OCI_ATTR_DIRPATH_EXPR_TYPE Attribute

21-36

21-23

Setting a Function Context as a Column Attribute

21-39

21-24

Allocating a Child Column Array for a Function Context

21-41

22-1

Object Type Representation of a Department Row

22-18

22-2

C Representation of a Department Row

22-18

23-1

Initializing and Terminating XML Context with a C API

23-2

24-1

Definition of the Employee Object Type Listed in the Intype File

24-2

24-2

Contents of the Generated Header File demo.h

24-3

24-3

Contents of the demov.c File

24-3

24-4

Invoking OTT from the Command Line

24-5

24-5

Contents of a User-Created Intype File

24-9

24-6

Object Type Definition for Employee

24-10

24-7

OTT-Generated Struct Declarations

24-10

24-8

Object Type Definitions for the OTT Type Mapping Example

24-13

24-9

Various Type Mappings Created by OTT from Object Type Definitions

24-13

24-10

Object Type and Subtype Definitions

24-16

24-11

Contents of the Intype File

24-16

xlix

24-12

OTT Generates C Structs for the Types and Null Indicator Structs

24-16

24-13

Contents of an Intype File

24-19

24-14

Contents of the Outtype File After Running OTT

24-19

24-15

Content of an Intype File Named ex2c.typ

24-22

24-16

Invoking OTT and Specifying the Initialization Function

24-22

24-17

Content of an OTT-Generated File Named ex2cv.c

24-22

24-18

Object Type Definition to Demonstrate How OTT Generates Include Files

24-33

24-19

Content of the Intype File

24-33

24-20

Invoking OTT from the Command Line

24-33

24-21

Content of the Header File tott95b.h

24-33

24-22

Content of the Header File tott95a.h

24-34

24-23

Construct to Use to Conditionally Include the Header File tott95b.h

24-34

26-1

Creating a Compound Sharding Key

26-147

26-2

Custom Pool Example

26-150

36-1

Creating a Collection

36-3

36-2

Creating a Document

36-10

36-3

Creating a Document with a Key

36-12

36-4

Creating a Document with a Key and Multimedia Type

36-14

36-5

Finding One Document Using a Key

36-16

F-1

Setting Configuration Parameters and Starting agtctl

F-5

l

List of Figures
4-1

Basic OCI Program Flow

4-2

4-2

Components of a Service Context

4-6

4-3

Statement Handles

4-8

4-4

Direct Path Handles

4-10

6-1

Steps in Processing SQL Statements

6-2

7-1

Using OCIBindByName() to Associate Placeholders with Program Variables

7-2

7-2

Determining Skip Parameters

7-23

7-3

Performing Piecewise Insert

7-49

7-4

Performing Piecewise Fetch

7-53

8-1

OCIDescribeAny() Table Description

10-1

Multiple Tightly Coupled Branches

10-5

10-2

Session Operating on Multiple Branches

10-5

11-1

OCI Connection Pooling

11-17

13-1

Publish-Subscribe Model

13-3

19-1

Basic Object Operational Flow

19-7

21-1

Direct Path Loading

21-1

21-2

Inheritance Hierarchy for a Column of Type Person

22-1

Object Cache

22-2

Object Graph of person_t Instances

22-20

24-1

Using OTT with OCI

24-20

27-1

Classification of Instances by Type and Lifetime

35-1

Execution Flow of the OCIXStreamInLCRCallbackSend() Function

35-46

35-2

Execution Flow of the OCIXStreamOutLCRCallbackReceive() Function

35-62

F-1

Multithreaded extproc Agent Architecture

8-2

21-29
22-3

27-2

F-3

li

List of Tables
2-1

Instant Client Shared Libraries for Linux and UNIX

2-2

2-2

Instant Client Shared Libraries for Microsoft Windows

2-2

2-3

Instant Client Light Shared Libraries Linux and UNIX

2-9

2-4

Instant Client Light Shared Libraries for Microsoft Windows

2-9

3-1

ORACLE_HOME Directories and Contents

3-2

3-2

Equivalent OCI Parameter Settings in oraaccess.xml and sqlnet.ora

3-11

3-3

Obsolescent OCI Functions

3-22

3-4

OCI Functions Not Supported

3-24

4-1

OCI Handle Types

4-2

Descriptor Types

4-12

4-3

OCI Return Codes

4-27

4-4

Return and Error Codes

4-28

4-5

Oracle Reserved Namespaces

4-35

5-1

Internal Oracle Database Data Types

5-4

5-2

External Data Types and Codes

5-7

5-3

VARNUM Examples

5-16

5-4

Format of the DATE Data Type

5-17

5-5

Data Conversions

5-29

5-6

Data Conversions for LOBs

5-30

5-7

Data Conversion for Datetime and Interval Types

5-31

5-8

Data Conversion for External Data Types to Internal Numeric Data Types

5-33

5-9

Data Conversions for Internal to External Numeric Data Types

5-33

5-10

OCITypeCode Values and Data Types

5-34

5-11

OCI_TYPECODE to SQLT Mappings

5-36

6-1

OCI_ATTR_STMT_TYPE Values and Statement Types

6-4

7-1

Information Summary for Bind Types

7-9

8-1

Attributes of All Parameters

8-5

8-2

Attributes of Tables or Views

8-7

8-3

Attributes Specific to Tables

8-8

8-4

Attributes of Procedures or Functions

8-8

8-5

Attributes Specific to Package Subprograms

8-8

8-6

Attributes of Packages

8-9

8-7

Attributes of Types

8-9

8-8

Attributes of Type Attributes

8-11

8-9

Attributes of Type Methods

8-12

4-3

lii

8-10

Attributes of Collection Types

8-13

8-11

Attributes of Synonyms

8-14

8-12

Attributes of Sequences

8-15

8-13

Attributes of Columns of Tables or Views

8-16

8-14

Predefined Collation IDs, Their ub4 Values (in parenthesis), and Their SQL Names

8-18

8-15

Attributes of Arguments and Results

8-19

8-16

List Attributes

8-21

8-17

Attributes Specific to Schemas

8-21

8-18

Attributes Specific to Databases

8-21

8-19

Attributes Specific to Rules

8-23

8-20

Attributes Specific to Rule Sets

8-23

8-21

Attributes Specific to Evaluation Contexts

8-23

8-22

Attributes Specific to Table Aliases

8-24

8-23

Attributes Specific to Variable Types

8-24

8-24

Attributes Specific to Name-Value Pair

8-25

9-1

LOB Functions Compatibility and Migration

10-1

Global Transaction Identifier

10-4

10-2

One-Phase Commit

10-9

10-3

Two-Phase Commit

10-9

10-4

Read-Only Update Fails

10-10

10-5

Read-Only Transaction

10-11

10-6

Initialization and Termination Multithreading Functions

10-38

10-7

Passive Threading Primitives

10-40

10-8

Active Threading Primitives

10-43

12-1

Time and Event

12-13

13-1

Publish-Subscribe Functions

13-11

13-2

AQ Functions

13-24

13-3

Enqueue Parameters

13-24

13-4

Dequeue Parameters

13-25

13-5

Listen Parameters

13-25

13-6

Array Enqueue Parameters

13-26

13-7

Array Dequeue Parameters

13-26

13-8

Agent Parameters

13-27

13-9

Message Properties

13-27

13-10

Enqueue Option Attributes

13-28

13-11

Dequeue Option Attributes

13-28

15-1

Comparison of Some Connection Specific Auto-Tuning Parameters

15-17

9-8

liii

19-1

Meta-Attributes of Persistent Objects

19-17

19-2

Set and Check Functions

19-20

19-3

Transient Meta-Attributes

19-20

19-4

Attribute Values for New Objects

19-32

20-1

Function Prefix Examples

20-5

20-2

Binding and Defining Datetime and Interval Data Types

20-8

20-3

Datetime Functions

20-9

20-4

Interval Functions

20-11

20-5

String Functions

20-15

20-6

Raw Functions

20-16

20-7

Collection Functions

20-19

20-8

Collection Scanning Functions

20-19

20-9

Nested Table Functions

20-21

20-10

REF Manipulation Functions

20-24

20-11

Descriptor Objects

20-26

20-12

Data Type Mappings for Binds and Defines

20-40

21-1

Direct Path Context Functions

21-7

21-2

Direct Path Column Array Functions

21-8

22-1

Object Attributes After a Refresh Operation

22-12

22-2

Example of Allocation and Pin Durations

22-17

22-3

Pin, Free, and Unpin Functions

22-22

22-4

Flush and Refresh Functions

22-22

22-5

Mark and Unmark Functions

22-23

22-6

Object Meta-Attributes Functions

22-23

22-7

Other Object Functions

22-23

24-1

Object Data Type Mappings for Object Type Attributes

24-11

25-1

Mode of a Parameter

25-2

25-2

Connect, Authorize, and Initialize Functions

25-3

25-3

Handle and Descriptor Functions

25-45

25-4

Bind, Define, and Describe Functions

25-58

26-1

Statement Functions

26-2

LOB Functions

26-15

26-3

Advanced Queuing and Publish-Subscribe Functions

26-79

26-4

Direct Path Loading Functions

26-96

26-5

Thread Management Functions

26-110

26-6

Transaction Functions

26-132

26-7

Sharding Functions

26-146

26-2

liv

26-8

Miscellaneous Functions

26-151

26-9

OCI Function Codes

26-172

26-10

Continuation of OCI Function Codes from 97 and Higher

26-173

27-1

Type and Lifetime of Instances

27-3

27-2

Return Values of Navigational Functions

27-4

27-3

OCI Navigational Functions Error Codes

27-4

27-4

Flush or Refresh Functions

27-6

27-5

Object Status After Refresh

27-12

27-6

Mark or Unmark Object and Cache Functions

27-13

27-7

Get Object Status Functions

27-20

27-8

Miscellaneous Object Functions

27-26

27-9

Instances Created

27-38

27-10

Pin, Unpin, and Free Functions

27-42

27-11

Type Information Accessor Functions

27-54

28-1

Function Return Values

28-2

28-2

Collection and Iterator Functions

28-3

28-3

Element Pointers

28-8

28-4

Date Functions

28-25

28-5

Error Bits Returned by the valid Parameter for OCIDateCheck()

28-30

28-6

Comparison Results

28-31

28-7

Error Bits Returned by the valid Parameter for OCIDateTimeCheck()

28-40

28-8

Comparison Results Returned by the result Parameter for OCIDateTimeCompare()

28-41

28-9

Error Bits Returned by the valid Parameter for OCIIntervalCheck()

28-61

28-10

Comparison Results Returned by the result Parameter for OCIIntervalCompare()

28-62

28-11

NUMBER Functions

28-74

28-12

Comparison Results Returned by the result Parameter for OCINumberCmp()

28-81

28-13

Values of result

28-102

28-14

Raw Functions

28-110

28-15

Ref Functions

28-116

28-16

String Functions

28-124

28-17

Table Functions

28-130

29-1

External Procedures Functions

29-2

29-2

Memory Services Functions

29-6

29-3

Maintaining Context Functions

29-11

29-4

Parameter Manager Interface Functions

29-15

29-5

File I/O Interface Functions

29-26

29-6

String Formatting Functions

29-35

lv

29-7

Format Modifier Flags

29-38

29-8

Format Codes to Specify How to Format an Argument Written to a String

29-39

30-1

Function Return Values

30-1

30-2

Type Interface Functions

30-2

30-3

Any Data Functions

30-7

30-4

Data Types and Attribute Values

30-10

30-5

Data Types and Attribute Values

30-13

30-6

Any Data Set Functions

30-24

31-1

Function Return Values

31-1

31-2

OCI Locale Functions

31-2

31-3

OCI Locale-Mapping Function

31-8

31-4

OCI String Manipulation Functions

31-10

31-5

OCI Character Classification Functions

31-34

31-6

OCI Character Set Conversion Functions

31-41

31-7

OCI Messaging Functions

31-46

32-1

Function Return Values

32-1

32-2

OCI XML DB Functions

32-2

35-1

Mode of a Parameter

35-5

35-2

OCI XStream Functions

35-5

35-3

Table Column Data Types

35-23

35-4

Required Column List in the First LCR

35-52

35-5

Storage of LOB or LONG Data in the LCR

35-66

36-1

OCI SODA Functions

36-1

A-1

Function Code of the SQL Command Associated with the SQL Statement

A-47

B-1

OCI Demonstration Programs

B-1

C-1

Server Round-Trips for Relational Operations

C-2

C-2

Server Round-Trips for OCILob Calls

C-3

C-3

Server Round-Trips for Object and Cache Functions

C-5

C-4

Server Round-Trips for Describe Operations

C-6

C-5

Server Round-Trips for Data Type Manipulation Functions

C-7

C-6

Server Round-Trips for Any Type and Data Functions

C-7

C-7

Locally Processed Functions

C-7

D-1

ORACLE_HOME Directories and Contents

D-2

D-2

Oracle XA Components

D-4

D-3

Link Libraries

D-5

E-1

Deprecated OCI Functions

E-1

E-2

Deprecated Initialize Functions

E-2

lvi

E-3

Deprecated Statement Functions

E-6

E-4

Deprecated LOB Functions

E-9

E-5

Characters or Bytes in amtp for OCILobRead()

E-16

E-6

Characters or Bytes in amtp for OCILobWrite()

E-20

E-7

Characters or Bytes in amtp for OCILobWriteAppend()

E-24

E-8

Deprecated Streams Advanced Queuing Functions

E-27

F-1

Agent Control Utility (agtctl) Commands

F-2

Configuration Parameters for agtctl

F-5
F-10

lvii

Preface

Preface
Oracle Call Interface (OCI) is an application programming interface (API) that lets
applications written in C or C++ interact with Oracle Database. OCI gives your
programs the capability to perform the full range of database operations that are
possible with Oracle Database, including SQL statement processing and object
manipulation.

Audience
This guide is intended for programmers developing new applications or converting
existing applications to run in the Oracle Database environment. This comprehensive
treatment of OCI is also valuable to systems analysts, project managers, and others
interested in the development of database applications.
This guide assumes that you have a working knowledge of application programming
using C. Readers should also be familiar with the use of structured query language
(SQL) to access information in relational database systems. In addition, some sections
of this guide assume knowledge of the basic concepts of object-oriented programming.

See Also:
•

Oracle Database SQL Language ReferenceandOracle Database
Administrator’s Guide for information about SQL

•

Oracle Database Concepts

•

Oracle Database New Features Guide for information about the
differences between the Standard Edition and the Enterprise Edition and
all the features and options that are available to you

•

Oracle C++ Call Interface Programmer's Guide for more information
about OCI functionality for C++ that enables programmers to manipulate
database objects of user-defined types as C++ objects

Documentation Accessibility
For information about Oracle's commitment to accessibility, visit the Oracle
Accessibility Program website at http://www.oracle.com/pls/topic/lookup?
ctx=acc&id=docacc.

lviii

Preface

Access to Oracle Support
Oracle customers that have purchased support have access to electronic support
through My Oracle Support. For information, visit http://www.oracle.com/pls/topic/
lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs
if you are hearing impaired.

Related Documents
Many of the examples in this book use the sample schemas, which are installed by
default when you select the Basic Installation option with an Oracle Database
installation. See Oracle Database Sample Schemas for information about how these
schemas were created and how you can use them.
To download free release notes, installation documentation, white papers, or other
collateral, visit the Oracle Technology Network (OTN). You must register online before
using OTN; registration is free and can be done at
http://www.oracle.com/technetwork/community/join/overview/

If you have a user name and password for OTN, then you can go directly to the
documentation section of the OTN Web site at
http://www.oracle.com/technetwork/indexes/documentation/

Oracle Call Interface Programmer's Guide does not contain all information that
describes the features and functionality of OCI in the Oracle Database Standard
Edition and Enterprise Edition products. Explore the following documents for additional
information about OCI.
•

Oracle Database Data Cartridge Developer's Guide provides information about
cartridge services and OCI calls pertaining to development of data cartridges.

•

Oracle Database Globalization Support Guide explains OCI calls pertaining to NLS
settings and globalization support.

•

Oracle Database Advanced Queuing User's Guide supplies information about OCI
calls pertaining to Advanced Queuing.

•

Oracle Database Development Guide explains how to use OCI with the XA library.

•

Oracle Database SecureFiles and Large Objects Developer's Guide provides
information about using OCI calls to manipulate LOBs, including code examples.

•

Oracle Database Object-Relational Developer's Guide offers a detailed
explanation of object types.

For additional information about Oracle Database, consult the following documents:
•

Oracle Database Net Services Administrator's Guide

•

Oracle Database New Features Guide

•

Oracle Database Concepts

•

Oracle Database Reference

•

Oracle Database Error Messages Reference

lix

Preface

Conventions
The following text conventions are used in this document:
Convention

Meaning

boldface

Boldface type indicates graphical user interface elements associated
with an action, or terms defined in text or the glossary.

italic

Italic type indicates book titles, emphasis, or placeholder variables for
which you supply particular values.

monospace

Monospace type indicates commands within a paragraph, URLs, code
in examples, text that appears on the screen, or text that you enter.

lx

Changes in This Release for Oracle Call
Interface Programmer's Guide
This preface contains:
•

Changes in Oracle Database release 18c, version 18.1

Changes in Oracle Database Release 18c Version 18.1
Changes in Oracle Database release 18c, version 18.1.
The following are changes in the Oracle Call Interface (OCI):
•

New Features

New Features
New features for Oracle Database release 18c, version 18.1
The following features are new in this release:
•

OCI support for Simple Oracle Document Access (SODA)
SODA for C is a C API that is part of Oracle Call Interface (OCI). It implements
Simple Oracle Document Access (SODA). You can use it to perform create, read
(retrieve), update, and delete (CRUD) operations on documents of any kind, and
you can use it to query JSON documents. You compile programs that use SODA
for C the same way you compile other OCI programs. SODA is a set of NoSQLstyle APIs that let you create and store collections of documents in Oracle
Database, retrieve them, and query them, without needing to know Structured
Query Language (SQL) or how the data in the documents is stored in the
database. Oracle Database supports storing and querying JSON data. To access
this functionality, you need structured query language (SQL) with special JSON
SQL operators. SODA for C hides the complexities of SQL/JSON programming.
See the following for more information: Handles, SODA Collection Handle
Attributes, SODA Document Handle Attributes, OCI SODA Functions, SODA
Document Handle Attributes, and SODA Collection Handle Attributes.
See https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/
index.html.

•

OCI support for operation level timeout or fine grained timers for operations
New service context attribute OCI_ATTR_CALL_TIMEOUT — For setting millisecond
timeout values using the OCIAttrSet() function. Allows applications to specify a
timeout value for network calls to the database.
See OCI_ATTR_CALL_TIMEOUT for more information.

•

OCI support for Application Continuity in an HA infrastructure includes:

lxi

Changes in This Release for Oracle Call Interface Programmer's Guide

–

Support is added for OCI dynamic binds and defines for numeric, character,
and date/time types. This means the following OCI APIs are extended to
support Application Continuity: OCIBindDynamic() and OCIDefineDynamic().

–

Support is added for binding and defining objects. This means the following
OCI APIs are extended to support Application Continuity: OCIBindObject(),
OCIDefineObject(), and OCITypeByName().

–

During execution of LOB calls, Application Continuity now supports the
handling of connection failure by restarting LOB calls that were interrupted by
an outage.

–

OCI now supports the new Application Continuity FAILOVER_TYPE of AUTO, which
only attempts to fail over if the session state is known to be restorable at the
explicit request boundary.

See About Added Support for Application Continuity for more information.
•

OCI support for collations for bind variables
Using OCIAttrSet(), the OCI_ATTR_COLLATION_ID attribute can be set on a bind
variable handle to any of the supported collation IDs. The collation set with
OCI_ATTR_COLLATION_ID is used as the derived collation of the corresponding
placeholder expression (host variable reference) in the SQL statement.
See OCI_ATTR_COLLATION_ID for more information.

•

OCI support for Oracle Connection Manager in Traffic Director Mode
Oracle Connection Manager in Traffic Director Mode is a proxy that is placed
between the database clients and the database instances. Supported OCI clients
from Oracle Database 11g Release 2 (11.2) and later can connect to it. Oracle
Connection Manager in Traffic Director Mode provides improved high availability
(HA) for planned and unplanned database server outages, connection multiplexing
support, and load balancing.
Oracle Connection Manager in Traffic Director Mode can use the OCI client
oraaccess.xml configuration file to configure proxy resident connection pools for

one or more services that provide a proxy between the client and database
instances. This feature provides improved high availability and performance for
both planned and unplanned outages.
See About Using Oracle Connection Manager in Traffic Director Mode and About
OCI Session Pool Configuration in oraaccess.xml for more information.
•

New LOB descriptor attribute: OCI_ATTR_LOB_TYPE — Used to get the LOB type from
the LOB descriptor.
See OCI_ATTR_LOB_TYPE for more information.

•

New LOB locator attribute: OCI_ATTR_LOB_REMOTE — Determines whether the LOB
locator belongs to a local database table or a remote database table.
See OCI_ATTR_LOB_REMOTE for more information.

•

OCI_ATTR_STMT_TYPE — has one additional statement attribute types:

–

OCI_STMT_MERGE is added beginning Oracle Database release 18c, version 18.1.

See About Preparing Statements and OCI_ATTR_STMT_TYPE for more
information about these statement attribute types.
•

New user session handle attribute: OCI_ATTR_AUTOTUNING_ENABLED — checks if the
client user session has OCI auto tuning enabled on OCI client statement caching.

lxii

Changes in This Release for Oracle Call Interface Programmer's Guide

See OCI_ATTR_AUTOTUNING_ENABLED for more information.
•

Instant Client Basic and Basic Light ZIP files on Linux, Unix, and macOS now have
the libclntsh and libocci symbolic links precreated.
See the Note in Install from ZIP Files, from RPMs, and from Oracle Universal
Installer for more information.

•

Instant Client Basic and Basic Light Zips and RPMs now precreate a network/admin
directory, where optional files such as, tnsnames.ora, sqlnet.ora, and oraaccess.xml
can be placed.
See the Note in SDK for Oracle Instant Client for more information.

•

New session pool handle attribute: OCI_ATTR_SPOOL_MAX_USE_SESSION — Sets the
maximum number of times one session can be checked out of the session pool,
after which the session is automatically destroyed.
See OCI_ATTR_SPOOL_MAX_USE_SESSION for more information.

•

Two new column property flags for the OCI_ATTR_COL_PROPERTIES attibute:
–

OCI_ATTR_COL_PROPERTY_IS_LPART — Indicates whether this is an implicitly
generated logical partitioning column for container_map enabled objects.

–

OCI_ATTR_COL_PROPERTY_IS_CONID — Indicates whether this is a CON_ID column
implicitly generated by CONTAINERS() or is an ORIGIN_CON_ID column implicitly
generated for Extended Data Link.

See Column Attributes for more information.
•

Changes in server version macros
Because the components of the database version changed beginning with release
18c, version 18.1, there are new client macros provided for extracting each of the
components. As a result, the signature for the OCIClientVersion() call is changed
and there is a new OCIServerRelease2() call. The macros are named according to
the new release naming scheme beginning with version 18.1.
See OCIClientVersion() and OCIServerRelease2() for more information.

Deprecated Features
Deprecated features in Oracle Database release 18c, version 18.1.
The following features are deprecated in this release, and may be desupported in a
future releases:
•

OCI_DTYPE_RSET — Result set descriptor.

lxiii

1
OCI: Introduction
This chapter contains these topics:
•

Overview of OCI

•

Building an OCI Application

•

Alternatives to OCI

•

SQL Statements

•

Procedural and Nonprocedural Elements

•

Object Support

•

Simple Oracle Document Access (SODA)

•

Encapsulated Interfaces

•

User Authentication and Password Management

•

Features to Improve Application Performance and Scalability

•

Oracle Streams Advanced Queuing

•

XA Library Support

1.1 Overview of OCI
Oracle Call Interface (OCI) is an application programming interface (API) that lets you
create applications that use function calls to access an Oracle database and control all
phases of SQL statement execution and data access.
OCI supports the data types, calling conventions, syntax, and semantics of C and C+
+.
OCI provides:
•

High performance and scalability through the efficient use of system memory and
network connectivity

•

Consistent interfaces for dynamic session and transaction management in a twotier client/server or multitier environment

•

N-tier authentication

•

Comprehensive support for application development using Oracle Database
objects

•

Access to external databases, such as Oracle TimesTen In-Memory Database and
Oracle In-Memory Database Cache. See Oracle TimesTen In-Memory Database
C Developers Guide.

•

Applications that support an increasing number of users and requests without
additional hardware investments

•

Ways to manipulate data and schemas in an Oracle Database using the C
programming language and a library of standard database access and retrieval

1-1

Chapter 1

Overview of OCI

functions in the form of a dynamic runtime library (OCI library) that can be linked in
an application at run time.
•

Encapsulated or opaque interfaces, whose implementation details are unknown

•

Simplified user authentication and password management

•

Extensions to improve application performance and scalability

•

Consistent interface for transaction management

•

OCI extensions to support client-side access to Oracle objects

•

Significant advantages over other methods of accessing an Oracle Database:
–

More fine-grained control over all aspects of application design

–

High degree of control over program execution

–

Use of familiar third-generation language programming techniques and
application development tools, such as browsers and debuggers

–

Connection pooling, session pooling, and statement caching that enable
building of scalable applications

–

Support of dynamic SQL

–

Availability on the broadest range of operating systems of all the Oracle
programmatic interfaces

–

Dynamic binding and defining using callbacks

–

Description functionality to expose layers of server metadata

–

Asynchronous event notification for registered client applications

–

Enhanced array data manipulation language (DML) capability for array inserts,
updates, and deletes

–

Ability to associate commit requests with executes to reduce round-trips

–

Optimization of queries using transparent prefetch buffers to reduce roundtrips

–

Thread safety, which eliminates the need for mutual exclusive locks (mutexes)
on OCI handles

–

APIs to design a scalable, multithreaded application that can support large
numbers of users securely

–

SQL access functions, for managing database access, processing SQL
statements, and manipulating objects retrieved from an Oracle database

–

Data type mapping and manipulation functions, for manipulating data
attributes of Oracle types

–

Data loading functions, for loading data directly into the database without
using SQL statements

–

External procedure functions, for writing C callbacks from PL/SQL

1-2

Chapter 1

Building an OCI Application

See Also:
•

Oracle Call Interface

•

Related Documents

1.2 Building an OCI Application
You compile and link an OCI program in the same way that you compile and link a
non-database application. There is no need for a separate preprocessing or
precompilation step.
OCI supports most popular compilers. The details of linking an OCI program vary from
system to system. On some operating systems, it may be necessary to include other
libraries, in addition to the OCI library, to properly link your OCI programs. See your
Oracle Database system-specific documentation and the installation guide for more
information about compiling and linking an OCI application for your operating system.

See Also:
•

Building and Configuring OCI Applications

•

SDK for Oracle Instant Client

1.3 Alternatives to OCI
Some alternatives to using the Oracle Call Interface (OCI) include:
•

Oracle Database Programming Interface for C (ODPI-C)

•

Oracle C++ Call Interface (OCCI)

•

Oracle Pro*C/C++ Precompiler

•

Oracle ODBC Driver

Oracle Database Programming Interface for C (ODPI-C)
ODPI-C is an open source library of C code that simplifies the use of common Oracle
Call Interface (OCI) features for Oracle Database drivers and user applications. ODPIC sits on top of OCI and requires Oracle client libraries. ODPI-C:
•

Favors ease of use aimed at driver writers where niche special-case OCI features
are not needed.

•

Provides a faster implementation of drivers with considerably less code. Oracle
features can be exposed to users rapidly and in a consistent way.

•

Provides simpler memory management for binding variables and fetching.

•

Automatically converts binding and 'defining' (for fetches) to "native" C types so
that additional calls do not need to be made. This is beneficial particularly for

1-3

Chapter 1

Alternatives to OCI

numbers and dates. The ability to retrieve LONG and LOB columns as strings and
buffers is an advantage as well.
•

Provides a "safer" API in that resource handles are validated. Casts are not
needed. A reference counting mechanism adds resiliency by stopping applications
from destroying in-use OCI resources.

•

Provides an API that simplifies connection and resource management. For
example, it automatically does session pool pinging to provide better High
Availability.

•

Provides an alternative programming experience from OCI that uses a multiple
getter and setter model for handling attributes.

•

Provides a sample Makefile that builds ODPI-C as a shared library. Or, the ODPIC source code can be included in your project and built as you would build an OCI
application.

See Also:
ODPI-C Home Page, for a list of ODPI-C supported features and a list of
references including to its home page, code location on github, and
documentation

Oracle C++ Call Interface (OCCI)
The Oracle C++ Call Interface (OCCI) is an application programming interface (API)
that allows applications written in C++ to interact with one or more Oracle database
servers. OCCI gives your programs the ability to perform the full range of database
operations that are possible with an Oracle database server, including SQL statement
processing and object manipulation.

See Also:
Oracle C++ Call Interface Programmer's Guide

Oracle Pro*C/C++ Precompiler
Oracle Pro*C/C++ Precompiler is a programming tool that enables the user to embed
SQL statements in a high-level source program. The precompiler accepts the source
program as input, translates the embedded SQL statements into standard Oracle
runtime library calls, and generates a modified source program that you can compile,
link, and execute in the usual way.

See Also:
Pro*C/C++ Programmer's Guide

1-4

Chapter 1

SQL Statements

Oracle ODBC Driver
The Oracle ODBC Driver enables ODBC applications on Microsoft Windows, as well
as UNIX platforms like Linux, Solaris, IBM Advanced Interactive eXecutive (AIX), HPUX Itaniutm, and IBM Linux on Platform z read and write access to Oracle® databases
through the ODBC interface using Oracle Net Services software.

See Also:
Oracle Database Development Guide for more information about the Oracle
ODBC Driver

1.4 SQL Statements
One of the main tasks of an OCI application is to process SQL statements.
Different types of SQL statements require different processing steps in your program.
It is important to take this into account when coding your OCI application. Oracle
Database recognizes several types of SQL statements:
•

Data Definition Language (DDL)

•

Control Statements
–

Transaction Control

–

Session Control

–

System Control

•

Queries

•

Data Manipulation Language (DML)

•

PL/SQL

•

Embedded SQL

•

Special OCI Terms for SQL

See Also:
Using SQL Statements in OCI

1.4.1 Data Definition Language
Data definition language (DDL) statements manage schema objects in the database.
DDL statements create new tables, drop old tables, and establish other schema
objects. They also control access to schema objects.
The following is an example of creating and specifying access to a table:

1-5

Chapter 1

SQL Statements

CREATE TABLE employees
(name
VARCHAR2(20),
ssn
VARCHAR2(12),
empno
NUMBER(6),
mgr
NUMBER(6),
salary
NUMBER(6));
GRANT UPDATE, INSERT, DELETE ON employees TO donna;
REVOKE UPDATE ON employees FROM jamie;

DDL statements also allow you to work with objects in the Oracle database, as in the
following series of statements that create an object table:
CREATE TYPE
name
ssn
address

person_t AS OBJECT (
VARCHAR2(30),
VARCHAR2(12),
VARCHAR2(50));

CREATE TABLE person_tab OF person_t;

1.4.2 Control Statements
OCI applications treat transaction control, session control, and system control
statements as if they were DML statements.

See Also:
Oracle Database SQL Language Reference for information about these
types of statements

1.4.3 Data Manipulation Language
Data manipulation language (DML) statements can change data in the database
tables.
For example, DML statements are used to:
•

Insert new rows into a table

•

Update column values in existing rows

•

Delete rows from a table

•

Lock a table in the database

•

Explain the execution plan for a SQL statement

•

Require an application to supply data to the database using input (bind) variables

See Also:
About Binding Placeholders in OCI for more information about input bind
variables

1-6

Chapter 1

SQL Statements

DML statements also allow you to work with objects in the Oracle database, as in the
following example, which inserts an instance of type person_t into the object table
person_tab:
INSERT INTO person_tab
VALUES (person_t('Steve May','987-65-4320','146 Winfield Street'));

1.4.4 Queries
Queries are statements that retrieve data from a database.
A query can return zero, one, or many rows of data. All queries begin with the SQL
keyword SELECT, as in the following example:
SELECT dname FROM dept
WHERE deptno = 42;

Queries access data in tables, and they are often classified with DML statements.
However, OCI applications process queries differently, so they are considered
separately in this guide.
Queries can require the program to supply data to the database using input (bind)
variables, as in the following example:
SELECT name
FROM employees
WHERE empno = :empnumber;

In the preceding SQL statement, :empnumber is a placeholder for a value that is to be
supplied by the application.
When processing a query, an OCI application also must define output variables to
receive the returned results. In the preceding statement, you must define an output
variable to receive any name values returned from the query.

See Also:
•

Overview of Binding in OCI for more information about input bind
variables

•

Overview of Defining in OCI for information about defining output
variables

•

Using SQL Statements in OCI for detailed information about how SQL
statements are processed in an OCI program

1.4.5 PL/SQL
PL/SQL is Oracle's procedural extension to the SQL language.
PL/SQL processes tasks that are more complicated than simple queries and SQL data
manipulation language statements. PL/SQL allows some constructs to be grouped into
a single block and executed as a unit. Among these are:
•

One or more SQL statements

1-7

Chapter 1

SQL Statements

•

Variable declarations

•

Assignment statements

•

Procedural control statements (IF...THEN...ELSE statements and loops)

•

Exception handling

You can use PL/SQL blocks in your OCI program to:
•

Call Oracle Database stored procedures and stored functions

•

Combine procedural control statements with several SQL statements, so that they
are executed as a unit

•

Access special PL/SQL features such as records, tables, cursor FOR loops, and
exception handling

•

Use cursor variables

•

Take advantage of implicit result set capability that allows reuse of existing stored
procedure designs that return implicit result sets

•

Access and manipulate objects in an Oracle database

The following PL/SQL example issues a SQL statement to retrieve values from a table
of employees, given a particular employee number. This example also demonstrates
the use of placeholders in PL/SQL statements.
BEGIN
SELECT ename, sal, comm INTO :emp_name, :salary, :commission
FROM emp
WHERE empno = :emp_number;
END;

Note that the placeholders in this statement are not PL/SQL variables. They represent
input values passed to the database when the statement is processed. These
placeholders must be bound to C language variables in your program.

See Also:
•

Oracle Database PL/SQL Language Reference for information about
coding PL/SQL blocks

•

About Binding Placeholders in PL/SQL for information about working
with placeholders in PL/SQL

1.4.6 Embedded SQL
OCI processes SQL statements as text strings that an application passes to the
database on execution.
The Oracle precompilers (Pro*C/C++, Pro*COBOL, Pro*FORTRAN) allow you to
embed SQL statements directly into your application code. A separate precompilation
step is then necessary to generate an executable application.
It is possible to mix OCI calls and embedded SQL in a precompiler program.

1-8

Chapter 1

Procedural and Nonprocedural Elements

See Also:
Pro*C/C++ Programmer's Guide

1.4.7 Special OCI Terms for SQL
This guide uses special terms to refer to the different parts of a SQL statement.
For example, consider the following SQL statement:
SELECT customer, address
FROM customers
WHERE bus_type = 'SOFTWARE'
AND sales_volume = :sales;

It contains the following parts:
•

A SQL command - SELECT

•

Two select-list items - customer and address

•

A table name in the FROM clause - customers

•

Two column names in the WHERE clause - bus_type and sales_volume

•

A literal input value in the WHERE clause - 'SOFTWARE'

•

A placeholder for an input variable in the WHERE clause - :sales

When you develop your OCI application, you call routines that specify to the Oracle
database the address (location) of input and output variables of your program. In this
guide, specifying the address of a placeholder variable for data input is called a bind
operation. Specifying the address of a variable to receive select-list items is called a
define operation.
For PL/SQL, both input and output specifications are called bind operations.

See Also:
•

Using SQL Statements in OCI for more information about these terms
and operations

1.5 Procedural and Nonprocedural Elements
OCI enables you to develop scalable, multithreaded applications in a multitier
architecture that combines the nonprocedural data access power of structured query
language (SQL) with the procedural capabilities of C and C++.
•

In a nonprocedural language program, the set of data to be operated on is
specified, but what operations are to be performed, or how the operations are to
be conducted, is not specified. The nonprocedural nature of SQL makes it an easy
language to learn and to use to perform database transactions. It is also the

1-9

Chapter 1

Object Support

standard language used to access and manipulate data in modern relational and
object-relational database systems.
•

In a procedural language program, the execution of most statements depends on
previous or subsequent statements and on control structures, such as loops or
conditional branches, that are not available in SQL. The procedural nature of these
languages makes them more complex than SQL, but it also makes them more
flexible and powerful.

The combination of both nonprocedural and procedural language elements in an OCI
program provides easy access to an Oracle database in a structured programming
environment.
OCI supports all SQL data definition, data manipulation, query, and transaction control
facilities that are available through an Oracle database. For example, an OCI program
can run a query against an Oracle database. The query can require the program to
supply data to the database using input (bind) variables, as follows:
SELECT name FROM employees WHERE empno = :empnumber;

In the preceding SQL statement, :empnumber is a placeholder for a value that is to be
supplied by the application.
You can also take advantage of PL/SQL, Oracle's procedural extension to SQL. The
applications you develop can be more powerful and flexible than applications written in
SQL alone. OCI also provides facilities for accessing and manipulating objects in a
database.

1.6 Object Support
OCI has facilities for working with object types and objects.
An object type is a user-defined data structure representing an abstraction of a realworld entity. For example, the database might contain a definition of a person object.
That object might have attributes—first_name, last_name, and age—to represent a
person's identifying characteristics.
The object type definition serves as the basis for creating objects that represent
instances of the object type by using the object type as a structural definition, you
could create a person object with the attribute values 'John', 'Bonivento', and '30'.
Object types may also contain methods—programmatic functions that represent the
behavior of that object type.
OCI provides a comprehensive application programming interface for programmers
seeking to use Oracle Database object capabilities.
These capabilities include:
•

Executing SQL statements that manipulate object data and schema information

•

Passing of object references and instances as input variables in SQL statements

•

Declaring object references and instances as variables to receive the output of
SQL statements

•

Fetching object references and instances from a database

•

Describing the properties of SQL statements that return object instances and
references

•

Describing PL/SQL procedures or functions with object parameters or results

1-10

Chapter 1

Object Support

•

Extension of commit and rollback calls to synchronize object and relational
functionality

OCI object features can be divided into the following major categories:
•

Client-Side Object Cache

•

Associative and Navigational Interfaces to access and manipulate objects

•

OCI Runtime Environment for Objects

•

Type Management: Mapping and Manipulation Functions to access information
about object types and control data attributes of Oracle types

•

Object Type Translator (OTT) utility, for mapping internal Oracle Database
schema information to client-side language bind variables

See Also:
•

Encapsulated Interfaces which describes additional OCI calls that are
provided to support manipulation of objects after they have been
accessed by SQL statements

•

Oracle Database Concepts

•

Oracle Database Object-Relational Developer's Guide

1.6.1 Client-Side Object Cache
The object cache is a client-side memory buffer that provides lookup and memory
management support for objects.
The object cache stores and tracks object instances that have been fetched by an OCI
application from the server to the client side. The object cache is created when the
OCI environment is initialized. When multiple applications run against the same server,
each has its own object cache. The cache tracks the objects that are currently in
memory, maintains references to objects, manages automatic object swapping, and
tracks the meta-attributes or type information about objects. The object cache provides
the following features to OCI applications:
•

Improved application performance by reducing the number of client/server roundtrips required to fetch and operate on objects

•

Enhanced scalability by supporting object swapping from the client-side cache

•

Improved concurrency by supporting object-level locking

1.6.2 Associative and Navigational Interfaces
What are the different types of interfaces OCI applications can use to access objects?
Applications using OCI can access objects in an Oracle database through several
types of interfaces:
•

Using SQL SELECT, INSERT, and UPDATE statements

•

Using a C-style pointer chasing scheme to access objects in the client-side cache
by traversing the corresponding smart pointers or REFs

1-11

Chapter 1

Object Support

OCI provides a set of functions with extensions to support object manipulation using
SQL SELECT, INSERT, and UPDATE statements. To access Oracle Database objects, these
SQL statements use a consistent set of steps as if they were accessing relational
tables. OCI provides the following sets of functions required to access objects:
•

Binding and defining object type instances and references as input and output
variables of SQL statements

•

Executing SQL statements that contain object type instances and references

•

Fetching object type instances and references

•

Describing select-list items of an Oracle object type

OCI also provides a set of functions using a C-style pointer chasing scheme to access
objects after they have been fetched into the client-side cache by traversing the
corresponding smart pointers or REFs. This navigational interface provides functions
for:
•

Instantiating a copy of a referenceable persistent object (that is, of a persistent
object with object ID in the client-side cache) by pinning its smart pointer or REF

•

Traversing a sequence of objects that are connected to each other by traversing
the REFs that point from one to the other

•

Dynamically getting and setting values of an object's attributes

1.6.3 OCI Runtime Environment for Objects
OCI provides functions for objects to manage how Oracle Database objects are used
on the client side.
These functions provide for:
•

Connecting to an Oracle database server to access its object functionality,
including initializing a session, logging on to a database server, and registering a
connection

•

Setting up the client-side object cache and tuning its parameters

•

Getting errors and warning messages

•

Controlling transactions that access objects in the database

•

Associatively accessing objects through SQL

•

Describing PL/SQL procedures or functions whose parameters or results are
Oracle types

1.6.4 Type Management: Mapping and Manipulation Functions
OCI provides two sets of functions to work with Oracle Database objects.
•

Type Mapping functions allow applications to map attributes of an Oracle schema
represented in the server as internal Oracle data types to their corresponding host
language types.

•

Type Manipulation functions allow host language applications to manipulate
individual attributes of an Oracle schema such as setting and getting their values
and flushing their values to the server.

1-12

Chapter 1

Simple Oracle Document Access (SODA)

Additionally, the OCIDescribeAny() function provides information about objects stored in
the database.

1.6.5 Object Type Translator
The Object Type Translator (OTT) utility translates schema information about Oracle
object types into client-side language bindings of host language variables, such as
structures.
The OTT takes as input an intype file that contains metadata information about Oracle
schema objects. It generates an outtype file and the header and implementation files
that must be included in a C application that runs against the object schema. Both OCI
applications and Pro*C/C++ precompiler applications may include code generated by
the OTT. The OTT is beneficial because it:
•

Improves application developer productivity: OTT eliminates the need for you to
code the host language variables that correspond to schema objects.

•

Maintains SQL as the data definition language of choice: By providing the ability to
automatically map Oracle schema objects that are created using SQL to host
language variables, OTT facilitates the use of SQL as the data definition language
of choice. This in turn allows Oracle Database to support a consistent model of
data.

•

Facilitates schema evolution of object types: OTT regenerates included header
files when the schema is changed, allowing Oracle applications to support schema
evolution.

OTT is typically invoked from the command line by specifying the intype file, the
outtype file, and the specific database connection. With Oracle Database, OTT can
only generate C structures that can either be used with OCI programs or with the
Pro*C/C++ precompiler programs.

1.7 Simple Oracle Document Access (SODA)
SODA for C is a C API that is part of Oracle Call Interface (OCI).
SODA for C implements Simple Oracle Document Access (SODA). You can use it to
perform create, read (retrieve), update, and delete (CRUD) operations on documents
of any kind, and you can use it to query JSON documents. You compile programs that
use SODA for C the same way you compile other OCI programs. SODA is a set of
NoSQL-style APIs that let you create and store collections of documents in Oracle
Database, retrieve them, and query them, without needing to know Structured Query
Language (SQL) or how the data in the documents is stored in the database. Oracle
Database supports storing and querying JSON data. To access this functionality, you
need structured query language (SQL) with special JSON SQL operators. SODA for C
hides the complexities of SQL/JSON programming.

1-13

Chapter 1

Encapsulated Interfaces

See Also:
•

Handles, SODA Collection Handle Attributes, SODA Document Handle
Attributes, OCI SODA Functions, SODA Document Handle Attributes,
and SODA Collection Handle Attributes.

•

See https://docs.oracle.com/en/database/oracle/oracle-database/18/
adsdc/index.html

1.8 Encapsulated Interfaces
All the data structures that are used by OCI calls are encapsulated in the form of
opaque interfaces that are called handles.
A handle is an opaque pointer to a storage area allocated by the OCI library that
stores context information, connection information, error information, or bind
information about a SQL or PL/SQL statement. A client allocates certain types of
handles, populates one or more of those handles through well-defined interfaces, and
sends requests to the server using those handles. In turn, applications can access the
specific information contained in a handle by using accessor functions.
The OCI library manages a hierarchy of handles. Encapsulating the OCI interfaces
with these handles has several benefits to the application developer, including:
•

Reduction of server-side state information that must be retained, thereby reducing
server-side memory usage

•

Improvement of productivity by eliminating the need for global variables, making
error reporting easier, and providing consistency in the way OCI variables are
accessed and used

•

Allows changes to be made to the underlying structure without affecting
applications

1.9 User Authentication and Password Management
OCI provides application developers with user authentication and password
management.
This is supported in several ways:
•

OCI enables a single OCI application to authenticate and maintain multiple users.

•

OCI enables the application to update a user's password, which is particularly
helpful if an expired password message is returned by an authentication attempt.

OCI supports two types of login sessions:
•

A login function for sessions by which a single user connects to the database
using a login name and password

•

A mechanism by which a single OCI application authenticates and maintains
multiple sessions by separating the login session (the session created when a
user logs in to an Oracle database) from the user sessions (all other sessions
created by a user)

1-14

Chapter 1

Features to Improve Application Performance and Scalability

Privileged connections, such as SYSDBA, SYSOPER, proxy authentication, external
authentication, and others, are also supported.

1.10 Features to Improve Application Performance and
Scalability
OCI provides several feature extensions to improve application performance and
scalability.
Application performance has been improved by reducing the number of client to server
round-trips required, and scalability improvements have been made by reducing the
amount of state information that must be retained on the server side. Some of these
features include:
•

Statement caching to improve performance by caching executable statements that
are used repeatedly

•

Client result caching to limit the number of round trips to the database server

•

Implicit prefetching of SELECT statement result sets to eliminate the describe roundtrip, reduce round-trips, and reduce memory usage

•

Elimination of open and close cursor round-trips

•

Support for multithreaded environments

•

Session multiplexing over connections

•

Consistent support for a variety of configurations, including standard two-tier client/
server configurations, server-to-server transaction coordination, and three-tier
transaction processing (TP)-monitor configurations

•

Consistent support for local and global transactions, including support for the XA
interface's TM_JOIN operation

•

Improved scalability by providing the ability to concentrate connections, processes,
and sessions across users on connections and by eliminating the need for
separate sessions to be created for each branch of a global transaction

•

Allowing applications to authenticate multiple users and allow transactions to be
started on their behalf

1.11 Oracle Streams Advanced Queuing
OCI provides an interface to Oracle Streams Advanced Queuing (Streams AQ)
feature.
Streams AQ provides message queuing as an integrated part of Oracle Database.
Streams AQ provides this functionality by integrating the queuing system with the
database, thereby creating a message-enabled database. By providing an integrated
solution, Streams AQ frees you to devote your efforts to your specific business logic
rather than having to construct a messaging infrastructure.

1-15

Chapter 1

XA Library Support

See Also:
OCI and Streams Advanced Queuing

1.12 XA Library Support
OCI supports the Oracle XA library.
The xa.h header file is in the same location as all the other OCI header files. For Linux
or UNIX, the path is $ORACLE_HOME/rdbms/public. Users of the demo_rdbms.mk file on
Linux or UNIX are not affected because this make file includes the $ORACLE_HOME/rdbms/
public directory.
For Windows, the path is ORACLE_BASE\ORACLE_HOME\oci\include.

See Also:
•

Oracle XA Library for more information about Windows and XA
applications

•

Oracle Database Development Guide for information about developing
applications with Oracle XA

1-16

2
Oracle Instant Client and Oracle Instant
Client Light
This chapter contains the following topics:
•

About Oracle Instant Client

•

Install from ZIP Files, from RPMs, and from Oracle Universal Installer

•

Environment Variables for Oracle Instant Client

•

Database Connection Strings for Oracle Instant Client

•

SDK for Oracle Instant Client

•

About Oracle Instant Client Light

•

About Patching Oracle Instant Client Shared Libraries on Linux or UNIX

•

Regeneration of Data Shared Library and Zip and RPM Files

2.1 About Oracle Instant Client
Oracle Instant Client provides the necessary Oracle Database client-side files to
create and run OCI, OCCI, ODBC, and JDBC OCI applications. Useful command-line
utilities including SQL*Plus, SQL*Loader and Oracle Data Pump are also available.
Oracle Instant Client simplifies the deployment of applications by eliminating the need
for an Oracle home on the client machines.
The storage space requirement of an OCI application running in Instant Client mode is
significantly reduced compared to the same application running in a full client-side
installation. A minimal install of Instant Client shared libraries can occupy less than
10% of the space of a full client-side installation. Finally, the Instant Client is easy to
install.
Why use Instant Client?
•

Installation involves unzipping a few files, or installing RPM packages.

•

The Oracle Database client-side number of required files and the total disk storage
are significantly reduced.

•

There is no loss of functionality or performance for applications deployed using
Instant Client.

•

It is simple for independent software vendors to package applications.

A README file is included with the Instant Client installation. It describes the version,
date and time, and the operating system the Instant Client was generated on.
OCI applications, by default, look for the OCI Data Shared Library, libociei.so (or
Oraociei18.1.dll on Windows) in the runtime library search path (for example
LD_LIBRARY_PATH on Linux, or PATH on Windows) to determine if the application should
operate in the Instant Client mode. If this library is not found, then OCI tries to load the
Instant Client Light Data Shared Library (see Table 2-3 and Table 2-4), libociicus.so

2-1

Chapter 2

About Oracle Instant Client

(or Oraociicus18.1.dll on Windows). If the Instant Client Light library is found, then the
application operates in the Instant Client Light mode. Otherwise, a full installation
based on Oracle home is assumed.
For Instant Client, the following tables shows the Oracle Database client-side files
required to deploy an OCI application for Linux and UNIX and Microsoft Windows.
Other libraries and utilities get installed, but are not needed for OCI runtime use. For
example, you can delete files such as jdbc.jar.
Table 2-1

Instant Client Shared Libraries for Linux and UNIX

Linux and UNIX

Description for Linux and UNIX

libclntsh.so.18.1

Client Code Library

libclntshcore.so.18.1
libociei.so1

OCI Instant Client Data Shared
Library

libnnz18.so

Security Library

libons.so

Oracle Notification Service (ONS)
library

libmql1.so

Light Weight IPC Library

libipc1.so

Message Queue Light Library

1

The libraries libclntsh.so.18.1, libclntshcore.so.18.1, and libociei.so must reside in the same directory in
order to use Instant Client.

Table 2-2

Instant Client Shared Libraries for Microsoft Windows

Microsoft Windows

Description for Microsoft Windows

oci.dll

Forwarding functions that applications link with

oraociei18.dll

Data and code

orannzsbb18.dll

Security Library

oraons.dll

ONS library used by OCI internally

oci.sym

Symbol tables

oraociei18.sym
orannzsbb18.sym

Oracle Database 18c library names are used in the table and are current for Oracle
Database release 18c, version 18.1.
On Microsoft Windows, a .sym file is provided for each dynamic-link library (DLL).
When the .sym file is present in the same location as the DLL, a stack trace with
function names is generated when a failure occurs in OCI on Microsoft Windows.
In general, all OCI functionality is available to an application being run using the
Instant Client, except that the Instant Client is for client-side operation only. Therefore,
server-side external procedures cannot use Instant Client libraries.
For development you can also use the Instant Client SDK.

2-2

Chapter 2

Install from ZIP Files, from RPMs, and from Oracle Universal Installer

See Also:
•

SDK for Oracle Instant Client

•

Fault Diagnosability in OCI

2.2 Install from ZIP Files, from RPMs, and from Oracle
Universal Installer
Oracle Instant Client can be installed in several ways.
The Instant Client libraries can be installed by either choosing the Instant Client option
from Oracle Universal Installer or by downloading and installing either the ZIP files or
RPMs from the OCI page on the Oracle Technology Network website: Oracle Instant
Client
To Download and Install the Instant Client Libraries from the Oracle Technology
Network Website
The following steps are for the Linux, Unix, and Windows environments.
1.

From the Oracle Technology Network, download and unzip the required ZIP
packages from OTN to an empty directory, such as instantclient_18_1, for Oracle
Database release 18c, version 18.1. All Instant Client ZIP installs require the Basic
or Basic Light package.

2.

Or, to install the RPM files, follow these instructions:
a.

Become root by running su and entering the super-user password.

b.

Change to the directory in which you want to install.

c.

Uninstall any earlier installations.
# rpm -e package-name

d.

Install each package with yum. Yum will automatically install required
dependencies, such as libaio.
# yum remove package-name
# yum install package-name.rpm

Or, install each package with rpm.
# rpm -ivh package-name.rpm

3.

e.

Delete the .rpm files if you want to save disk space.

f.

Exit the root shell. No need to reboot.

Set the operating system shared library path environment variable to the directory
from Step 1. For example, with ZIP files on Linux or UNIX, set LD_LIBRARY_PATH to
instantclient_18_1.
export LD_LIBRARY_PATH=/opt/oracle/instantclient_18_1:$LD_LIBRARY_PATH

With Linux RPMs, set LD_LIBRARY_PATH to:
export LD_LIBRARY_PATH=/usr/lib/oracle/18.1/client64/lib:$LD_LIBRARY_PATH

2-3

Chapter 2

Install from ZIP Files, from RPMs, and from Oracle Universal Installer

On Windows, set PATH to the instantclient_18_1 directory. For example, on
Windows 7, update PATH in Control Panel -> System -> Advanced System
Settings -> Advanced -> Environment Variables -> System Variables -> PATH.
4.

5.

If necessary, set the NLS_LANG environment variable to specify the language and
territory used by the client application and database connections opened by the
application, and the client's character set, which is the character set for data
entered or displayed by a client program. NLS_LANG is set as an environment
variable on UNIX platforms and is set in the registry on Windows platforms. See
Oracle Database Globalization Support Guide for more information on setting the
NLS_LANG environment variable.
If you intend to co-locate optional Oracle client configuration files such as
tnsnames.ora, sqlnet.ora, ldap.ora, or oraaccess.xml with Instant Client, then put
them in the network/admin subdirectory of Instant Client. This is the default Oracle

client configuration directory for applications linked with Instant Client.
Alternatively, Oracle client configuration files can be put in another, accessible
directory. Then set the environment variable TNS_ADMIN to that directory name.
After completing the preceding steps you are ready to run OCI applications.
The OCI application uses the Instant Client when the OCI shared libraries are
accessible through the operating system Library Path variable. In this way, there is no
dependency on the Oracle home and none of the other code and data files provided in
the Oracle home are needed by OCI.
Install the Instant Client from the Oracle Universal Installer
For Oracle Universal Installer, invoke the Oracle Universal Installer and select the
Instant Client option and install the Instant Client shared libraries to an empty
directory, such as instantclient_18_1, for Oracle Database release 18c, version 18.1.
See Steps 3 through 5 in To Download and Install the Instant Client Libraries from the
Oracle Technology Network Website about setting environment variables.
If you did a complete client installation (by choosing the Admin option in Oracle
Universal Installer), the locations of the Instant Client shared libraries in a full client
installation are:
On Linux or UNIX:
libociei.so library is in $ORACLE_HOME/instantclient
libclntsh.so.18.1, libclntshcore.so.18.1, and libnnz18.so are in $ORACLE_HOME/lib

On Windows:
oraociei18.dll library is in ORACLE_HOME\instantclient
oci.dll, ociw32.dll, and orannzsbb18.dll are in ORACLE_HOME\bin

To enable running the OCI application using Instant Client, copy the preceding
libraries to a different directory and set the operating system shared library path to
locate this directory.

2-4

Chapter 2

Environment Variables for Oracle Instant Client

Note:
All the libraries must be copied from the same Oracle home and must be
placed in the same directory. Co-location of symlinks to Instant Client
libraries is not a substitute for physical co-location of the libraries.
There should be only one set of Oracle libraries on the operating system
Library Path variable. That is, if you have multiple directories containing
Instant Client libraries, then only one such directory should be on the
operating system Library Path.
Similarly, if an Oracle home-based installation is performed on the same
system, then you should not have ORACLE_HOME/lib and the Instant Client
directory on the operating system Library Path simultaneously regardless of
the order in which they appear on the Library Path. That is, either the
ORACLE_HOME/lib directory (for non-Instant Client operation) or Instant Client
directory (for Instant Client operation) should be on the operating system
Library Path variable, but not both.

To enable other capabilities such as OCCI and JDBC OCI, you must copy a few
additional files. To enable OCCI, you must install the OCCI Library (libocci.so.18.1 on
Linux or UNIX and oraocci18.dll on Windows) in the Instant Client directory. For the
JDBC OCI driver, in addition to the three OCI shared libraries, you must also download
OCI JDBC Library (for example libocijdbc18.so on Linux or UNIX and ocijdbc18.dll
on Windows). Place all libraries in the Instant Client directory.

Note:
On hybrid platforms, such as Sparc64, to operate the JDBC OCI driver in the
Instant Client mode, copy the libociei.so library from the ORACLE_HOME/
instantclient32 directory to the Instant Client directory. Copy all other
Sparc64 libraries needed for the JDBC OCI Instant Client from the
ORACLE_HOME/lib32 directory to the Instant Client directory.

2.3 Environment Variables for Oracle Instant Client
The ORACLE_HOME environment variable no longer determines the location of NLS,
CORE, and error message files.
An OCI-only application should not require ORACLE_HOME to be set. However, if it is set, it
does not affect OCI. OCI always obtains its data from the Data Shared Library. If the
Data Shared Library is not available, only then is ORACLE_HOME used and a full client
installation is assumed. Though ORACLE_HOME is not required to be set, if it is set, then it
must be set to a valid operating system path name that identifies a directory.
If Dynamic User callback libraries are to be loaded, then as this guide specifies, the
callback package must reside in ORACLE_HOME/lib (ORACLE_HOME\bin on Windows). Set
ORACLE_HOME in this case.
Environment variables ORA_NLS10 and ORA_NLS_PROFILE33 are ignored in the Instant
Client mode.

2-5

Chapter 2

Database Connection Strings for Oracle Instant Client

Beginning with Oracle Database 12c Release 2 (12.2), when using Instant Client
libraries, the Instant Client can use the ORA_TZFILE environment variable to read the
time zone file from the file system when this environment variable is set. Otherwise, if
the ORA_TZFILE variable is not set, then the larger, default, timezlrg_n.dat file from the
Data Shared Library is used. If the smaller timezone_n.dat file is to be used from the
Data Shared Library, then set the ORA_TZFILE environment variable to the name of the
file without any absolute or relative path names. The file must be copied to
subdirectory oracore/zoneinfo for (UNIX/LINUX) or oracore\zoneinfo for (Microsoft
Windows) in the instant client directory. You can use the genezi utility with the -v option
to verify that the time zone file and location is valid or run SQL*Plus.
On Linux or UNIX:
export ORA_TZFILE=timezone_n.dat

On Windows:
set ORA_TZFILE=timezone_n.dat

In these examples, n is the time zone data file version number.
Be sure to create subdirectory oracore/zoneinfo for (UNIX/LINUX) or subdirectory
oracore\zoneinfo for (Microsoft Windows) where oracoei or oraociicus DLL's are
located (typically in the instantclient_12_2 directory) and copy the timezone_n.dat file
to this directory.
To determine the versions of small and large time zone files that are packaged in the
Instant Client Data Shared Library, enter the following command to run the genezi
utility:
genezi -v

If OCI is not operating in the Instant Client mode (because the Data Shared Library is
not available), then ORA_TZFILE variable, if set, names a complete path name as it does
in previous Oracle Database releases.
If TNSNAMES local naming parameters are used, then, as mentioned earlier, TNS_ADMIN
directory must contain the TNSNAMES configuration files. If TNS_ADMIN is not set, then the
ORACLE_HOME/network/admin directory must contain Oracle Net Services configuration
files.

2.4 Database Connection Strings for Oracle Instant Client
All Oracle Net naming methods that do not require use of ORACLE_BASE_HOME, or
ORACLE_HOME (to locate configuration files such as tnsnames.ora, sqlnet.ora, or
oraaccess.xml) work in the Instant Client mode.
If you intend to co-locate optional Oracle configuration files such as tnsnames.ora,
sqlnet.ora, ldap.ora, or oraaccess.xml with Instant Client, note that beginning with
Oracle Database release 18c, version 18.1 Instant Client Basic and Basic Light Zips
and RPMs precreate a network/admin directory, where these files can be placed. In
earlier releases, users had to create the network/admin directory themselves.
See Database Connection Strings for complete information about database connection
strings.

2-6

Chapter 2

SDK for Oracle Instant Client

See Also:
Oracle Database Net Services Administrator's Guide chapter on "Configuring
Naming Methods" for more about connect descriptors

This section includes the following topic: Examples of Oracle Instant Client Connect
Identifiers.

2.5 SDK for Oracle Instant Client
The software development kit (SDK) is a set of development tools that allows the
creation of applications can be downloaded from the Instant Client link URL on the
Oracle Technology Network website:
Oracle Instant Client
•

The Instant Client SDK package has both C and C++ header files and a makefile
for developing OCI and OCCI applications while in an Instant Client environment.
Developed applications can be deployed in any client environment.

•

The SDK contains C and C++ demonstration programs.

•

On Windows, libraries required to link the OCI or OCCI applications are also
included. Make.bat is provided to build the demos.

•

On UNIX or Linux, the makefile demo.mk is provided to build the demos. The
instantclient_18_1 directory must be in the runtime library search path, for
example LD_LIBRARY_PATH before linking the application. The OCI and OCCI
programs require the presence of libclntsh.so and libocci.so symbolic links in
the instantclient_18_1 directory. Beginning with Oracle Database 18c, version
18.1, Instant Client Basic and Basic Light ZIP files on Linux, Unix, and macOS
now have the libclntsh and libocci symbolic links precreated.

•

The SDK also contains the Object Type Translator (OTT) utility and its classes to
generate the application header files.

2.6 About Oracle Instant Client Light
The Instant Client Light version of Instant Client further reduces the disk space
requirements of the client installation.
The size of the library has been reduced by removing error message files for
languages other than English and leaving only a few supported character set
definitions out of around 250.
This Instant Client Light version is geared toward applications that use either
US7ASCII, WE8DEC, WE8ISO8859P1, WE8MSWIN1252, or a Unicode character set.
There is no restriction on the LANGUAGE and the TERRITORY fields of the NLS_LANG setting,
so the Instant Client Light operates with any language and territory settings. Because
only English error messages are provided with the Instant Client Light, error messages
generated on the client side, such as Net connection errors, are always reported in
English, even if NLS_LANG is set to a language other than AMERICAN. Error messages
generated by the database side, such as syntax errors in SQL statements, are in the

2-7

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About Oracle Instant Client Light

selected language provided the appropriate translated message files are installed in
the Oracle home of the database instance.
This section includes the following topics:
•

Globalization Settings

•

Libraries for Oracle Instant Client Light

•

Install from ZIP Files, from RPMs, and from Oracle Universal Installer

2.6.1 Globalization Settings
Instant Client Light supports the following client character sets:
Single-byte
•

US7ASCII

•

WE8DEC

•

WE8MSWIN1252

•

WE8ISO8859P1

Unicode
•

UTF8

•

AL16UTF16

•

AL32UTF8

Instant Client Light can connect to databases having one of these database character
sets:
•

US7ASCII

•

WE8DEC

•

WE8MSWIN1252

•

WE8ISO8859P1

•

WE8EBCDIC37C

•

WE8EBCDIC1047

•

UTF8

•

AL32UTF8

Instant Client Light returns an error if a character set other than those in the preceding
lists is used as the client or database character set.
Instant Client Light can also operate with the OCI Environment handles created in the
OCI_UTF16 mode.

See Also:
Oracle Database Globalization Support Guide for more information about
National Language Support (NLS) settings

2-8

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About Oracle Instant Client Light

2.6.2 Libraries for Oracle Instant Client Light
OCI applications, by default, look for the OCI Data Shared Library, libociei.so (or
Oraociei18.1.dll on Windows) in the runtime library search path (for example
LD_LIBRARY_PATH on Linux, or PATH on Windows) to determine if the application should
operate in the Instant Client mode.
If the OCI Data Shared Library is not found, then OCI tries to load the Instant Client
Light Data Shared Library (see Table 2-3 and Table 2-4), libociicus.so (or
Oraociicus18.1.dll on Windows). If the Instant Client Light library is found, then the
application operates in the Instant Client Light mode. Otherwise, a full installation
based on Oracle home is assumed.
Table 2-3

Instant Client Light Shared Libraries Linux and UNIX

Linux and UNIX

Description for Linux and UNIX

libclntsh.so.18.1

Client Code Library

libclntshcore.so.18.1
libociicus.so

OCI Instant Client Light Data Shared Library

libnnz18.so

Security Library

libmql1.so

Light Weight IPC Library

libipc1.so

Message Queue Light Library

Table 2-4

Instant Client Light Shared Libraries for Microsoft Windows

Microsoft Windows

Description for Microsoft Windows

oci.dll

Forwarding functions that applications link with

oraociicus18.dll

Data and code

orannzsbb18.dll

Security Library

oci.sym

Symbol tables

oraociicus18.sym
orannzsbb18.sym

See Also:
Instant Client Shared Libraries for Linux and UNIX Table 2-1
Instant Client Shared Libraries for Microsoft Windows Table 2-2

2.6.3 Installing Oracle Instant Client Light
How can Instant Client Light can be installed.
Instant Client Light can be installed in one of these ways:
•

Installed from Oracle Technology Network (OTN)

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About Patching Oracle Instant Client Shared Libraries on Linux or UNIX

The following URL is the Instant Client page on the Oracle Technology Network
website: Oracle Instant Client
For Instant Client Light, download and unzip the basiclite.zip package in to an
empty instantclient_12_2 directory.
•

Installed from an Instant Client Administrator installation
From the ORACLE_HOME/instantclient/light subdirectory, copy libociicus.so (or
oraociicus12.dll on Windows). The Instant Client directory on the LD_LIBRARY_PATH
(PATH on Windows) should contain the Instant Client Light Data Shared Library,
libociicus.so (oraociicus12.dll on Windows), instead of the larger OCI Instant
Client Data Shared Library, libociei.so (oraociei12.dll on Windows).

•

Installed from an Oracle Universal Installer installation
When you select the Instant Client option from the Oracle Universal Installer,
libociei.so (or oraociei12.dll on Windows) is installed in the base directory of the
installation, which means these files are placed on the LD_LIBRARY_PATH (PATH on
Windows).
The Instant Light Client Data Shared Library, libociicus.so (or oraociicus12.dll
on Windows), is installed in the light subdirectory of the base directory and not
enabled by default. Therefore, to operate in the Instant Client Light mode, the OCI
Data Shared Library, libociei.so (or Oraociei12.dll on Windows) must be deleted
or renamed and the Instant Client Light library must be copied from the light
subdirectory to the base directory of the installation.
For example, if Oracle Universal Installer has installed the Instant Client in
my_oraic_12_2 directory on the LD_LIBRARY_PATH (PATH on Windows), then use the

following command sequence to operate in the Instant Client Light mode:
cd my_oraic_12_2
rm libociei.so
mv light/libociicus.so .

Note:
To ensure that no incompatible binaries exist in the installation, always
copy and install the Instant Client files in to an empty directory.

2.7 About Patching Oracle Instant Client Shared Libraries on
Linux or UNIX
Because Instant Client is a deployment feature, the number and size of files (client
footprint) required to run an OCI application has been reduced.
Hence, all files needed to patch Instant Client shared libraries are not available in an
Instant Client deployment. A complete client installation based on Oracle home is
needed for patching. Use the opatch utility for patching.
After you apply the patch in an Oracle home environment, copy the files listed in About
Oracle Instant Client to the instant client directory, as described in Install from ZIP
Files, from RPMs, and from Oracle Universal Installer.

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Regeneration of Data Shared Library and Zip and RPM Files

Instead of copying individual files, you can generate Instant Client zip and RPM files
for OCI and OCCI, JDBC, and SQL*Plus as described in Regeneration of Data Shared
Library and Zip and RPM Files. Then, you can copy the zip and RPM files to the target
system and unzip them as described in Install from ZIP Files, from RPMs, and from
Oracle Universal Installer.
The opatch utility stores the patching information of the ORACLE_HOME installation in
libclntsh.so. This information can be retrieved by the following command:
genezi -v

If the Instant Client deployment system does not have the genezi utility, you can copy it
from the ORACLE_HOME/bin directory.

Note:
The opatch utility is not available on Windows.

2.8 Regeneration of Data Shared Library and Zip and RPM
Files
The process to regenerate the data shared library and the zip and RPM files changed
in Oracle Database 12c Release 1 (12.1).
Separate make file targets are used to create the data shared libraries, zip, and RPM
files either individually or all at once. Currently, ilibociei builds only the zip and RPM
files. Regeneration of data shared libraries requires both a compiler and linker, which
may not be available on all installations. The sections that follow show the make file
target used to regenerate data shared libraries, zip, and RPM files.

Note:
The regenerated Instant Client binaries contain only the Instant Client files
installed in the Oracle Client Administrator Home from which the
regeneration is done. Therefore, error messages, character set encodings,
and time zone files that are present in the regeneration environment are the
only ones that are packaged in the data shared libraries. Error messages,
character set encodings, and time zone files depend on which national
languages were selected for the installation of the Oracle Client
Administrator Home.
Regeneration of the data shared library and the zip and RPM files is not
available on Windows platforms.

This section includes the following topics:
•

Regenerating Data Shared Library libociei.so

•

Regenerating Data Shared Library libociicus.so

•

Regenerating Data Shared Libraries libociei.so and libociicus.so in One Step

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Regeneration of Data Shared Library and Zip and RPM Files

•

Regenerating Zip and RPM Files for the Basic Package

•

Regenerating Zip and RPM Files for the Basic Light Package

•

Regenerating Zip and RPM Files for the JDBC Package

•

Regenerating Zip and RPM Files for the ODBC Package

•

Regenerating Zip and RPM Files for the SQL*Plus Package

•

Regenerating Zip and RPM Files for the Tools Package

•

Regenerating Zip and RPM Files for All Packages

2.8.1 Regenerating Data Shared Library libociei.so
The OCI Instant Client Data Shared Library (libociei.so) can be regenerated by using
the following commands in an Administrator Install of ORACLE_HOME:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenlibociei

The new regenerated libociei.so is placed in the ORACLE_HOME/instantclient directory.
The original existing libociei.so located in this same directory is renamed to
libociei.so0.

2.8.2 Regenerating Data Shared Library libociicus.so
To regenerate Instant Client Light data shared library (libociicus.so), use the following
commands:
mkdir -p $ORACLE_HOME/rdbms/install/instantclient/light
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenlibociicus

The newly regenerated libociicus.so is placed in the ORACLE_HOME/instantclient/light
directory. The original existing libociicus.so located in this same directory is renamed
to libociicus.so0.

2.8.3 Regenerating Data Shared Libraries libociei.so and libociicus.so
in One Step
To regenerate the data shared libraries libociei.so and libociicus.so, use the following
commands:
mkdir -p $ORACLE_HOME/rdbms/install/instantclient/light
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenliboci

The newly regenerated libociei.so is placed in the ORACLE_HOME/instantclient
directory. The original existing libociei.so located in this same directory is renamed to
libociei.so0.
The newly regenerated libociicus.so is placed in the ORACLE_HOME/instantclient/light
directory. The original existing libociicus.so located in this same directory is renamed
to libociicus.so0.

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Regeneration of Data Shared Library and Zip and RPM Files

2.8.4 Regenerating Zip and RPM Files for the Basic Package
To regenerate the zip and RPM files for the basic package, use the following
commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_basic_zip

2.8.5 Regenerating Zip and RPM Files for the Basic Light Package
To regenerate the zip and RPM files for the basic light package, use the following
commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_basiclite_zip

2.8.6 Regenerating Zip and RPM Files for the JDBC Package
To regenerate the zip and RPM files for the JDBC package, use the following
commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_jdbc_zip

2.8.7 Regenerating Zip and RPM Files for the ODBC Package
To regenerate the zip and RPM files for the ODBC package, use the following
commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_odbc_zip

2.8.8 Regenerating Zip and RPM Files for the SQL*Plus Package
To regenerate the zip and RPM files for the SQL*Plus package, use the following
commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_sqlplus_zip

2.8.9 Regenerating Zip and RPM Files for the Tools Package
To regenerate the zip and RPM files for the tools package, use the following
commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_tools_zip

2.8.10 Regenerating Zip and RPM Files for All Packages
To regenerate the zip and RPM files for all packages, use the following commands:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ilibociei

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Regeneration of Data Shared Library and Zip and RPM Files

The new zip and RPM files are generated under the following directory:
$ORACLE_HOME/rdbms/install/instantclient

Regeneration of the data shared library and the zip and RPM files is not available on
Windows platforms.

2-14

3
Building and Configuring OCI Applications
This chapter describes features about building and configuring OCI applications on
Linux, UNIX, and Windows operating systems.
For other supported operating systems, see the platform specific installation guides for
more information.
This chapter includes the following topics:
•

Header File and Makefile Locations

•

Building an OCI Application on Linux and UNIX

•

Building an Application on Windows

•

Database Connection Strings

•

Client and Server Operating with Different Versions of Time Zone Files

•

OCI Client-Side Deployment Parameters Using oraaccess.xml

•

About Compatibility and Upgrading

•

Fault Diagnosability in OCI

3.1 Header File and Makefile Locations
The OCI and OCCI header files that are required for OCI and OCCI client application
development on Linux and UNIX operating systems reside in the $ORACLE_HOME/rdbms/
public directory.
These files are available both with the Oracle Database Server installation, and with
the Oracle Database Client Administration and Custom installations. See the SDK for
Oracle Instant Client for information about it containing C and C++ header files and a
Makefile for developing OCI and OCCI applications while in an Instant Client
environment.
All demonstration programs and their related header files reside in the $ORACLE_HOME/
rdbms/demo directory once they are installed. These demonstration files are installable
only from the Examples media. See OCI Demonstration Programs for the names of
these programs and their purposes.
Several makefiles are provided in the demo directory. Each makefile contains
comments with instructions on its use in building OCI executables. Oracle
recommends that you use these demonstration makefiles whenever possible to avoid
errors in compilation and linking.
The demo_rdbms.mk file in the demo directory and is an example makefile. See the
comments on how to build the demonstration OCI programs. The demo_rdbms.mk file
includes the $ORACLE_HOME/rdbms/public directory. Ensure that your own customized
makefiles have the $ORACLE_HOME/rdbms/public directory in the INCLUDE path.
The ociucb.mk file is a makefile in demo for building a callback shared library.

3-1

Chapter 3

Building an OCI Application on Linux and UNIX

3.2 Building an OCI Application on Linux and UNIX
How to build an OCI application on Linux and UNIX.
This topic describes the features of OCI that apply to building applications on Linux
and UNIX in the following topics:
•

Oracle Directory Structure

•

Demonstration OCI Programs

See Also:
•

Oracle Database Client Installation Guide for Linux for operating system
requirements for x86–64 Linux platforms, supported Oracle Linux and
Red Hat Enterprise distributions for x86-64 platforms, and installation
requirements for programming environments for Linux x86-64

•

Oracle Database Instant Client Installation Guide for Apple Mac OS X
(Intel) for checking the software requirements

3.2.1 Oracle Directory Structure
The $ORACLE_HOME directory contains the following directories described in the following
table that are relevant to OCI.
These directories are for the full client and Oracle Database, but not for the Oracle
Instant Client. These files include the library files needed to link and run OCI
applications, and link with other Oracle products.
Table 3-1

ORACLE_HOME Directories and Contents

Directory Name

Contents

/admin

Configuration files

/demo

Sample programs, make files, SQL files, and
so forth

/imclude

Header files

/lib

Library files

/mesg

Message files

/public

Public header files

3.2.2 Demonstration OCI Programs
A set of OCI demonstration programs and their corresponding project files are
optionally installed after an Oracle Database installation and set up in the ORACLE_BASE/
ORACLE_HOME/demo subdirectory.

3-2

Chapter 3

Building an Application on Windows

Build and run these OCI demonstration programs to familiarize yourself with the steps
involved in developing OCI applications.
To build a demo OCI program, run the make file (demo_rdbms.mk) located in the /demo
directory. For example, to build a single OCI demo, use the following make command
syntax:
make -f demo_rdbms.mk build EXE=demo OBJS="demo.o ..."

For example, to build the OCI cdemo81.c program, enter the following make command:
make -f demo_rdbms.mk build EXE=cdemo81 OBJS=cdemo81.o

In this example, the executable file is created or updated from the object file, which in
turn is made by compiling the source file cdemo81.c.

See Also:
•

Oracle Database Examples Installation Guide for information about
installing the demonstration OCI programs using Oracle Universal
Installer

•

Downloads: Oracle Database 12c Release 2 (12.2.0.1.0) Standard
Edition 2 and Enterprise Edition for a link to the Oracle Database 12c
Release 2 Examples (12.2.0.1.0) for Linux x86-64
linuxx64_12201_examples.zip

•

Review the contents of the demo_rdbms.mk file to learn more about running
the many other OCI demonstration programs that are available in the
demo subdirectory.

•

OCI Demonstration Programs for more information about OCI
demonstration programs

3.3 Building an Application on Windows
How to build an OCI application on Windows.
See Getting Started with OCI for Windows for complete information.

See Also:
Oracle Database Client Installation Guide for Microsoft Windows for
information about Oracle Database software client requirements.

3.4 Database Connection Strings
This topic describes Oracle Net naming methods that do not use ORACLE_BASE_HOME, or
ORACLE_HOME (to locate configuration files such as tnsnames.ora, sqlnet.ora, or
oraaccess.xml).

3-3

Chapter 3

Database Connection Strings

In particular, the connect_identifier in the OCIServerAttach() call can be specified in
the following formats:
•

An easy connect naming string of the form:
username/password@host[:port][/service name][:server][/instance_name]

•

As a local naming parameters tnsnames.ora configuration file entry of the form:
net_service_name=
(DESCRIPTION=
(ADDRESS=(protocol_address_information))
(CONNECT_DATA=
(SERVICE_NAME=service_name)))

•

As an Oracle Net connect descriptor of the form:
"(DESCRIPTION=(ADDRESS=(PROTOCOL=protocol-name) (HOST=host-name) (PORT=portnumber))
(CONNECT_DATA=(SERVICE_NAME=service-name)))"

•

A Connection Name that is resolved through Directory Naming where the site is
configured for LDAP server discovery.

For naming methods such as tnsnames.ora and directory naming to work, the TNS_ADMIN
environment variable can also be set.
If the TNS_ADMIN environment variable is not set, and tnsnames.ora entries such as
inst1, and so on, are used, then the ORACLE_HOME variable must be set, and the
configuration files are expected to be in the $ORACLE_HOME/network/admin directory. Note
that the ORACLE_HOME variable in this case is only used for locating Oracle Net
configuration files, and no other component of Client Code Library (OCI, NLS, and so
on) uses the value of ORACLE_HOME. So it is preferred and easier to set the TNS_ADMIN
environment variable to establish the location of the tnsnames.ora file.
If a NULL string, "", is used as the connection string in the OCIServerAttach() call, then
the TWO_TASK environment variable can be set to the connect_identifier. On a Windows
operating system, the LOCAL environment variable is used instead of TWO_TASK.
Similarly, for OCI applications such as SQL*Plus, the TWO_TASK (or LOCAL on Windows)
environment variable can be set to the connect_identifier. Its value can be anything
that would have gone to the right of the '@' on a typical connect string.

See Also:
•

Oracle Database Net Services Administrator's Guide chapter on
"Configuring Naming Methods" for more about connect descriptors

•

Examples of Oracle Instant Client Connect Identifiers

3.4.1 Examples of Oracle Instant Client Connect Identifiers
If you are using SQL*Plus in Instant Client mode, then you can specify the connect
identifier in the following ways:
If the listener.ora file on the Oracle database contains the following:

3-4

Chapter 3

Database Connection Strings

LISTENER = (ADDRESS_LIST=
(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))
)
SID_LIST_LISTENER = (SID_LIST=
(SID_DESC=(SID_NAME=rdbms3)(GLOBAL_DBNAME=rdbms3.server6.us.alchemy.com)
(ORACLE_HOME=/home/dba/rdbms3/oracle))
)

The SQL*Plus connect identifier is:
"server6:1573/rdbms3.server6.us.alchemy.com"

The connect identifier can also be specified as:
"(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))(CONNECT_DATA=
(SERVICE_NAME=rdbms3.server6.us.alchemy.com)))"

Alternatively, you can set the TWO_TASK environment variable to any of the previous
connect identifiers and connect without specifying the connect identifier. For example:
export TWO_TASK=//server6:1573/rdbms3.server6.us.alchemy.com

You can also specify the TWO_TASK environment variable as:
export TWO_TASK=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))
(CONNECT_DATA=(SERVICE_NAME=rdbms3.server6.us.alchemy.com)))

Then you can invoke SQL*Plus with an empty connect identifier (you are prompted for
the password):
sqlplus user

The connect descriptor can also be stored in the tnsnames.ora file. For example, if the
tnsnames.ora file contains the following connect descriptor:
conn_str = (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=server6)(PORT=1573))
(CONNECT_DATA=
(SERVICE_NAME=rdbms3.server6.us.alchemy.com)))

If the tnsnames.ora file is located in the /home/webuser/instantclient directory, then you
can set the variable TNS_ADMIN (or LOCAL on Windows) as:
export TNS_ADMIN=/home/webuser/instantclient

Then you can use the connect identifier conn_str for invoking SQL*Plus, or for your
OCI connection.

Note:
TNS_ADMIN specifies the directory where the tnsnames.ora file is located and
TNS_ADMIN is not the full path of the tnsnames.ora file.

If the preceding tnsnames.ora file is located in an installation based Oracle home, in
the /network/server6/home/dba/oracle/network/admin directory, then the ORACLE_HOME
environment variable can be set as follows and SQL*Plus can be invoked as
previously, with the identifier conn_str:

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Chapter 3

Client and Server Operating with Different Versions of Time Zone Files

export ORACLE_HOME=/network/server6/home/dba/oracle

Finally, if tnsnames.ora can be located by TNS_ADMIN or ORACLE_HOME, then the TWO_TASK
environment variable can be set as follows enabling you to invoke SQL*Plus without a
connect identifier:
export TWO_TASK=conn_str

3.5 Client and Server Operating with Different Versions of
Time Zone Files
In Oracle Database Release 11.2 (or later) you can use different versions of the time
zone file on the client and server; this mode of operation was not supported before
Oracle Database Release 11.2.
Both client and server must be 11.2 or later to operate in such a mixed mode. This
section discusses the ramifications of operating in such a mode. To avoid these
ramifications use the same time zone file version for client and server.
The following behavior is seen when the client and server use different time zones file
versions. Note that the use of different time zone file versions only affects the handling
of TIMESTAMP WITH TIMEZONE (TSTZ) data type values.
•

The OCI Datetime and Interval APIs listed here unconditionally raise an error
when the input parameters are of TSTZ type. This is because these operations
depend on the local time zone file on the client that is not synchronized with the
database. Continuing with the computation in such a configuration can result in
inconsistent computations across the client and database tiers.
OCIDateTimeCompare()
OCIDateTimeConstruct()
OCIDateTimeConvert()
OCIDateTimeSubtract()
OCIIntervalAdd()
OCIIntervalSubtract()
OCIIntervalFromTZ()
OCIDateTimeGetTimeZoneName()
OCIDateTimeGetTimeZoneOffset()1
OCIDateTimeSysTimeStamp()

•

There is a performance penalty when you retrieve or modify TSTZ values. The
performance penalty arises because of the additional conversions needed to
compensate for the client and server using different time zone file versions.

•

If new time zone regions are defined by the more recent time zone file, you can
see an error operating on a TIMESTAMP WITH TIMEZONE value belonging to the new
region on a node that has a time zone file version that does not recognize the new
time zone region.

Applications that manipulate opaque type or XMLType instances or both containing TSTZ
type attributes must use the same time zone file version on client and server to avoid
data loss.

1

Returns an ORA-01805 error when timezone files on the client and server do not match (regions are not synchronized); returns
OCI_SUCCESS when region time zone values are the same (represent the same instant in UTC), though the TIME ZONE offsets are
different.

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OCI Client-Side Deployment Parameters Using oraaccess.xml

See Also:
Oracle Database Globalization Support Guide for information about
upgrading the time zone file and timestamp with time zone data

3.6 OCI Client-Side Deployment Parameters Using
oraaccess.xml
This topic describes the OCI client-side deployment parameters using oraaccess.xml.
This section includes the following topics:
•

About oraaccess.xml

•

About Client-Side Deployment Parameters Specified in oraaccess.xml

•

High Level Structure of oraaccess.xml

•

About Specifying Global Parameters in oraaccess.xml

•

About Specifying Defaults for Connection Parameters

•

Overriding Connection Parameters at the Connection-String Level

•

About OCI Session Pool Configuration in oraaccess.xml

•

File (oraaccess.xml) Properties

3.6.1 About oraaccess.xml
Starting with Oracle Database Release 12c Release 1 (12.1), Oracle provides an
oraaccess.xml file, a client-side configuration file.

You can use the oraaccess.xml file to configure selected OCI parameters (some of
which are accepted programatically in various OCI API calls), thereby allowing OCI
behavior to be changed during deployment without modifying the source code that
calls OCI.
Updates to the oraaccess.xml file will not affect already running clients. In order to pick
up any updates to the oraaccess.xml file, already running clients need to be restarted.
The oraaccess.xml file is read from the directory specified by the TNS_ADMIN environment
variable in regular and instant client installations. This is the $ORACLE_HOME/network/
admin directory on UNIX operating systems and the %ORACLE_HOME%\NETWORK\ADMIN
directory on Microsoft Windows operating systems, if TNS_ADMIN is not set in regular
client installations.

3.6.2 About Client-Side Deployment Parameters Specified in
oraaccess.xml
When equivalent parameters are set both in the sqlnet.ora and oraaccess.xml files, the
oraaccess.xml file setting takes precedence over the corresponding sqlnet.ora file
setting.

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OCI Client-Side Deployment Parameters Using oraaccess.xml

In such cases, Oracle recommends using the oraaccess.xml file settings moving
forward. For any network configuration, the sqlnet.ora file continues to be the primary
file as network level settings are not supported in the oraaccess.xml file.

3.6.3 High Level Structure of oraaccess.xml
Describes the high-level structure of the oraaccess.xml file.
The oraaccess.xml file has a top-level node  with the following three
elements:
•

 - This element describes any default parameter settings

shared across connections. These default parameters include:
–

Defaults for global parameters - These global parameters can only be
specified once and hence are applicable to all connections and cannot be
overridden at the connection level. These parameters are specified using the
following tags:
*

 - Creates the OCI Environment in OCI_EVENTS mode, which is

required for Fast Application Notification (FAN) and runtime connection
load balancing

–

*

 - Sets OCI client result cache parameters

*

 - Sets OCI fault diagnosability parameters

Defaults for connection-specific parameters - Connection parameters can be
set to different values for specific connections. However, they too can be
defaulted, and overridden on a per connection string basis as needed. These
defaults are shared across all connections (unless overridden at the
connection level, which is described in the  list item) that
follows. These defaults are specified by the following tags:
*

 - Sets the number of prefetch rows for all queries; specified
using the  parameter.

*

 - Sets the maximum number of statements that can be
cached per session; specified using the  parameter.

*

 - Consists of:  to turn auto tuning on or off;
, which sets the memory threshold for auto-tuning to stop

using more memory when available physical memory on the client system
has reached this threshold; and , which sets the memory
limit that OCI auto-tuning can use per client process.
*

 - Sets the action upon subscription
failure to be either the value trace or error.

*

 - Sets a variety of ONS client-side deployment configuration

parameters used for FAN notifications.
•

 - This element associates a configuration alias element
(), which is basically a name, with a specific set of parameters
() that contain one or more connection parameters. These connection

parameters are the same connection parameters within the element
 described previously, namely: , ,
,  and .

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•

 - This element associates one or more connection strings

used by an application with a config alias, thus allowing multiple connection string
elements to share the same set of parameters.
A connection configuration element () associates a connection
string element () with a configuration alias element
().
A connection string is indirectly associated with a set of parameters through the
configuration alias, which allows multiple connection string elements to share the
same set of parameters.
The sections that follow describe these client-side deployment parameters in more
detail.

See Also:
About Specifying Defaults for Connection Parameters

3.6.4 About Specifying Global Parameters in oraaccess.xml
As described, the  tag allows specifying default values for various
OCI parameters.
Of these, some parameters can only be specified once and hence apply to all
connections. These global parameters are described using the following tags:
•



This creates the OCI Environment in OCI_EVENTS mode, which is required for Fast
Application Notification (FAN) and runtime connection load balancing.

true 


•



–

 - Maximum size of any result set in rows in the per-process
query cache. Equivalent to OCI_RESULT_CACHE_MAX_RSET_ROWS in the sqlnet.ora
file.

–

 - Maximum client result cache size. Set the size to 32,768
bytes (32 Kilobytes (KB)) or greater. Equivalent to
OCI_RESULT_CACHE_MAX_RSET_SIZE in the sqlnet.ora file.

–

 - Maximum size in bytes for the per-process query cache.
Specifying a size less than 32,768 in the client disables the client result cache
feature. Equivalent to OCI_RESULT_CACHE_MAX_SIZE in the sqlnet.ora file.


10
65535
65535


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When equivalent parameters are set both in the sqlnet.ora and oraaccess.xml files,
the oraaccess.xml file setting takes precedence over the corresponding sqlnet.ora
file setting.
See Table 3-2 for a listing of equivalent OCI parameter settings.
•



You can specify the following elements:
–

 - Enables or disables diagnosability. Equivalent to
DIAG_ADR_ENABLED in the sqlnet.ora file. Values: true or false.

–

 - Enables or disables DDE. Values: true or false.

–

 - Sets the ADR base directory, which is a system-dependent
directory path string to designate the location of the ADR base to use in the
current ADRCI session. Equivalent to ADR_BASE in the sqlnet.ora file. Value:
directory path for ADR base directory.

–

 - Enables or disables OCI signal handler. Values: true or

false.
–

 - Enables or disables full dump files. Oracle Database client
contains advanced features for diagnosing issues, including the ability to dump
diagnostic information when important errors are detected. By default, these
dumps are restricted to a small subset of available information, to ensure that
application data is not dumped. However, in many installations, secure
locations for dump files may be configured, ensuring the privacy of such logs.
In such cases, it is recommended to turn on full dumps; this can greatly speed
resolution of issues. Full dumps can be enabled by specifying a value of false.
Values: true or false.

–

 - Indicates the trace event number and the level of tracing to be
in effect. Currently only event 10883 is supported. The available levels are 5
and 10.


false
false
/foo/adr
false
true


10883
5




When equivalent parameters are set both in the sqlnet.ora and oraaccess.xml files,
the oraaccess.xml file setting takes precedence over the corresponding sqlnet.ora
file setting.
See Table 3-2 for a listing of equivalent OCI parameter settings.

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Table 3-2 Equivalent OCI Parameter Settings in oraaccess.xml and
sqlnet.ora
Parameter Group

oraaccess.xml
Parameters

sqlnet.ora Parameters

OCI client result
cache



OCI_RESULT_CACHE_MAX_RSET_ROWS

OCI client result
cache



OCI_RESULT_CACHE_MAX_RSET_SIZE

OCI client result
cache



OCI_RESULT_CACHE_MAX_SIZE

OCI fault
diagnosability



DIAG_ADR_ENABLED

OCI fault
diagnosability



DIAG_DDE_ENABLED

OCI fault
diagnosability



ADR_BASE

See Also:
•

Oracle Database Development Guide for information about deployment
time settings for client result cache and client configuration file
parameters

•

Oracle Database Net Services Reference for more information about
ADR diagnostic parameters in the sqlnet.ora file

3.6.5 About Specifying Defaults for Connection Parameters
Describes the default values you can set for connection parameters shared across
connections.
You can specify the following connection parameters that are shared across
connections:
•

 - Specifies prefetch row count for SELECT statements.

100


Setting this parameter appropriately can help reduce round-trips to the database,
thereby improving application performance.
Note that this only overrides the OCI_ATTR_PREFETCH_ROWS parameter (whether
explicitly specified by the application or not). If the application has specified
OCI_ATTR_PREFETCH_MEMORY explicitly, then the actual prefetch row count will be
determined by using both constraints. The OCI_ATTR_PREFETCH_MEMORY constraint
equivalent cannot be specified in the oraaccess.xml file.
Also note that OCI prefetching may still get disabled if the SELECT statement
fetches columns of specific data types. For more details, see About Fetching
Results for information about limitations of OCI prefetch.

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•

 - Specifies the number of OCI Statement handles that can be

cached per session.

100


Caching statement handles improves repeat execute performance by reducing
client side and server side CPU consumption and network traffic.
Note that for this parameter to take effect, the application must be programmed to
use OCIStatementPrepare2() and OCIStatementRelease() calls (and not the older
OCISatementPrepare() and OCIHandleFree() equivalents for getting and disposing of
statement handles.
•

 - Used to enable OCI Auto tuning.

true
0.1
2M


Enabling auto-tuning can help OCI automatically tune the statement-cache size
based on specified memory constraints. This can help dynamically tune the
statement cache size to an appropriate value based on runtime application
characteristics and available memory resources.
Note that for auto tuning OCI Statement Cache, the application must be
programmed to use OCIStatementPrepare2() and OCIStatementRelease() calls (and
not the older OCISatementPrepare() and OCIHandleFree() equivalents for getting and
disposing of statement handles.
•

 - Used to determine how OCI responds to a

failure to subscribe for FAN notifications.
A value of trace records any failure to subscribe for FAN notifications (if FAN is
enabled) in the trace file and OCI proceeds ignoring the failure. A value of error
makes OCI return an error if an attempt to subscribe for FAN notifications fails.



trace



•

 - Sets up Oracle Notification Service (ONS) parameters.

You can specify the following connection parameters:
–

 - Length of time in seconds the client waits for its
subscription to the ONS server.

–

 - true or false. If true, the configuration specified in this section
will augment the auto configuration information that the client receives from
the database. If false, it will override the same.

–

 - Size in bytes of the event notification thread stack.

–

 - true or false. Whether debug mode is on (true) or off (false).

–

 - Directory that contains an auto logon wallet file for a
secure ONS subscription.

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–

 - Host list with ports and connection distribution.




5

true 
100k
true
/etc/oracle/wallets/


pacific
 3 <\max_connections>

10.228.215.121:25293,
10.228.215.122:25293



Europe
3<\max_connections>

myhost1.mydomain.com:25273,
myhost2.mydomain.com:25298,
myhost3.mydomain.com:30004





See Also:
•



•



•



•

Oracle Universal Connection Pool Developer’s Guide for information
about ONS configuration parameters

3.6.6 Overriding Connection Parameters at the Connection-String
Level
Using the oraaccess.xml file also allows you to override the very same set of
connection-specific parameters at the connection-string level as well.
This allows for overriding those connection-specific parameters based on
requirements of individual applications.
Using the  tag, you can specify a set of connection-specific
parameters () to be associated with a configuration alias (,
which creates a named group of connection-specific parameters). Thereafter, using
the  tag, you can associate one or more connection-strings

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OCI Client-Side Deployment Parameters Using oraaccess.xml

(specified using the  tag) with a . This permits a
level of indirection that allows multiple  elements to share the
same set of .
Example 1
This example shows a very simple oraaccess.xml file configuration that highlights
defaulting of global and connection parameters applicable across all connections.





50


100


100
10K
64M




Example 2
This example shows connection parameters being overridden at the connection level.





50


100


true
2.67
204800



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OCI Client-Side Deployment Parameters Using oraaccess.xml

100
10K
64M





bar


20




foo


15







hr_db
foo


finance_db
bar




Example 3
This example highlights setup for FAN notifications.








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OCI Client-Side Deployment Parameters Using oraaccess.xml

error




5

true

true



Example 4
This example highlights an advanced oraaccess.xml file configuration usage with
manual ONS settings. Manual ONS settings should be used rarely.







error




5

true



pacific
3
10.228.215.121:25293, 10.228.215.122:25293


Europe
3
myhost1.mydomain.com:25273,
myhost2.mydomain.com:25298,
myhost3.mydomain.com:30004



true



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OCI Client-Side Deployment Parameters Using oraaccess.xml

See Also:
About Specifying Defaults for Connection Parameters about overriding the
very same set of connection-specific parameters at the connection-string
level

3.6.7 About OCI Session Pool Configuration in oraaccess.xml
Beginning with Oracle Database release 18c, version 18.1, the OCI session pool
configuration can be set up using the oraaccess.xml client-side configuration file.
The OCI session pool is configured by specifying the following set of parameters in the
oraaccess.xml configuration file. These parameters can be specified in the default
parameters section or in the configuration descriptions section. If specified in the
default parameters section, then it applies to all the session pools in the application.
These settings can benefit any OCI Session Pool allowing OCI Session Pool settings
to be overridden.
•

 — Sets up session pool parameters.

–

 — Setting this to true makes the session pool configuration effective.
This is a mandatory parameter, that means, if the  parameter is
configured, then  parameter must also be configured.

•

 — Minimum number of connections in the pool. The default is 0.

•

 — Maximum number of connections in the pool. This is a mandatory
parameter, that means, if the  parameter is configured, then
 parameter must also be configured.

•

 — Amount of increase in the number of connections in the pool as the

pool expands. The default is 1.
•

 — Maximum time in seconds for which a connection stays

idle in the pool, after which it is terminated. The default is 0, that means, there is
no limit for which a connection stays idle in the pool.
•

 — Maximum number of times a connection can be taken and

released to the pool. The default is 0, that means, there is no limit to take a
connection and release to the pool.
•

 — Time, in seconds, a connection will stay after it has

been created in the pool. The default is 0, that means, there is no limit for a
connection to stay after it has been created in the pool.
Using the oraaccess.xml file allows you to configure an OCI session pool for each
needed connection service. The following example shows two groups of connection
parameters associated with its respective config alias, the sales_config and the
hr_config, where each connection string that the application uses is mapped with its
respective config alias, thus providing two OCI session pools.






 sales_config 


true
 10 
 100 
 5 




 hr_config 


true
 10 







sales.us.acme.com
sales_config


hr.us.acme.com
hr_config




3.6.8 File (oraaccess.xml) Properties
Lists some high level rules with regards to the oraaccess.xml file syntax stated here for
simplicity.
The XML schema specified in the oraaccess.xsd file is the ultimate formal reference for
oraaccess syntax:
•

The contents of the file are case sensitive, and all elements (tags, parameter
names) are in lower case.

•

Comments are allowed between parameters (nodes); for example, Comment "".

•

For the syntax with respect to the order of the parameters, see the XML Schema:
oraaccess.xsd file (see information about the oraaccess.xsd file later in this list).

•

For memory size, valid values and formats are 100, 100k, 100K, 1000M, and
1121m. This means only suffixes 'M', 'm', 'K', 'k', or no suffix are allowed. 'K' or 'k'

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About Compatibility and Upgrading

means kilobytes and 'M' or 'm' means megabytes. No suffix means the size is in
bytes.
•

 should be a decimal number between 0 and 100 and indicates a
percentage value.

•

Where a number is expected, only positive unsigned integers are allowed; no sign
is allowed. An example of a valid number usage is  100 ).

•

Configuration alias names (foo) are not casesensitive

•

String parameters (such as ) are not expected to be quoted.

•

These rules are all encapsulated in the schema definition.

•

OCI will report an error if OCI is provided an invalid oraaccess.xml file.

•

Before deploying an oraaccess.xml file, Oracle recommends that you validate it
with the Oracle supplied XML schema file: oraaccess.xsd. The schema file is
installed under ORACLE_HOME/rdbms/admin in a regular client and under
instantclient_12_2/sdk/admin in an instant client SDK. Customers can use their
own favorite XML validation tools to perform the validation after modifying the
oraaccess.xml file.

•

Sample oraaccess.xml files can be found in the ORACLE_HOME/rdbms/demo directory in
a regular client and in the instantclient_12_2/sdk/demo in an instant client. The
parameters in these files are for demonstration purpose only and should be
modified and tested as per the application's requirement before deploying it.

3.7 About Compatibility and Upgrading
The following sections discuss issues concerning compatibility between different
releases of OCI client and server, changes in the OCI library routines, and upgrading
an application from the release 7.x OCI to the current release of OCI:
•

Oracle Client and Server Cross Version Compatibility

•

Version Compatibility of Statically Linked and Dynamically Linked Applications

•

About Upgrading of Existing OCI Release 7 Applications

•

Obsolete OCI Routines

•

OCI Routines Not Supported

3.7.1 Oracle Client and Server Cross Version Compatibility
As a general guide, Oracle client and server versions are cross version compatible
with a number versions.
This means that you can connect to some older and newer versions of the database
and do not always have to upgrade both the client and server at the same time.
However, certain products or utilities may impose additional restrictions on supported
combinations specific to the product or utility.

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About Compatibility and Upgrading

See Also:
My Oracle Support Document 207303.1 for information about client and
server interoperability support matrix for different Oracle versions.

3.7.2 Version Compatibility of Statically Linked and Dynamically
Linked Applications
Here are the rules for relinking for a new release.
•

Statically linked OCI applications:
Statically linked OCI applications must be relinked for both major and minor
releases, because the statically linked Oracle Database client-side library code
may be incompatible with the error messages in the upgraded Oracle home. For
example, if an error message was updated with additional parameters then it is no
longer compatible with the statically linked code.

•

Dynamically linked OCI applications:
Dynamically linked OCI applications from Oracle Database 10g and later releases
need not be relinked. That is, the Oracle Database client-side dynamic library is
upwardly compatible with the previous version of the library. Oracle Universal
Installer creates a symbolic link for the previous version of the library that resolves
to the current version. Therefore, an application that is dynamically linked with the
previous version of the Oracle Database client-side dynamic library does not need
to be relinked to operate with the current version of the Oracle Database clientside library.

Note:
If the application is linked with a runtime library search path (such as rpath on Linux), then the application may still run with the version of

Oracle Database client-side library it is linked with. To run with the
current version of Oracle Database client-side library, it must be relinked.

See Also:
–

Oracle Database Upgrade Guide for information about compatibility
and upgrading

–

The server versions supported currently are found on My Oracle
Support Document 207303.1

3.7.3 About Upgrading of Existing OCI Release 7 Applications
OCI has been significantly improved with many features since OCI release 7.

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About Compatibility and Upgrading

Applications that use the OCI release 7.3 API work unchanged against the current
release of Oracle Database. They do need to be linked with the current client library.
However, OCI release 7.3 API has been deprecated and this option will not be
available in future Oracle releases.
OCI release 7 and the OCI calls of this release can be mixed in the same application
and in the same transaction provided they are not mixed within the same statement
execution. As a result, when migrating an existing OCI version 7 application you have
the following two alternatives:
•

Upgrade to the current OCI client but do not modify the application: If you choose
to upgrade from an Oracle release 7 OCI client to the current release OCI client,
you need only link the new version of the OCI library and need not recompile your
application. The relinked Oracle Database release 7 OCI applications work
unchanged against a current Oracle Database. This option is deprecated and will
not be available in future Oracle releases.

•

Upgrade to the current OCI client and modify the application: To use the
performance and scalability benefits provided by the current OCI, however, you
must modify your existing applications to use the current OCI programming
paradigm, rebuild and relink them with the current OCI library, and run them
against the current release of the Oracle database.

If you want to use any of the object capabilities of the current Oracle Database
release, you must upgrade your client to the current release of OCI.

Note:
Applications using version 7 API will not be able to connect to Oracle
Database 12c by default. Such applications willing to connect to Oracle
Database 12c must set sqlnet.allowed_logon_version to 8.
In Oracle Database 12c Release 2 (12.2), identifier length supported by
Oracle Database has been increased from 30 bytes to 128 bytes. With this
database change, OCI applications using deprecated V7 API odessp() may
need to be changed. In odessp() for the argument argnam, an application
needs to pass the two dimensional array, which can accommodate identifiers
of length 128 bytes, which was previously 30 bytes.
Applications using UPI API upidpr() may also need to be changed with long
identifiers in Oracle Database 12c Release 2 (12.2). In upidpr() for the
argument argument_name, an application needs to pass the two dimensional
array, which can accommodate identifiers of length 128 bytes, which was
previously 30 bytes.

See Also:
Programmer's Guide to the Oracle7 Server Call Interface in Oracle 7
Documentation.

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About Compatibility and Upgrading

3.7.4 Obsolete OCI Routines
Release 8.0 of the OCI introduced an entirely new set of functions that were not
available in release 7.3.
Oracle strongly recommends that new applications use the new calls to improve
performance and provide increased functionality. Future releases of Oracle will not be
supporting the release 7.3 API.
Table 3-3 lists the 7.x OCI calls with their later equivalents. For more information about
the OCI calls, see the function descriptions in this guide. For more information about
the 7.x calls, see Programmer's Guide to the Oracle Call Interface, Release 7.3.

Note:
In many cases the new or current OCI routines do not map directly onto the
7.x routines, so it almost may not be possible to simply replace one function
call and parameter list with another. Additional program logic may be
required before or after the new or current call is made. See the remaining
chapters, in particular OCI Programming Basics of this guide for more
information.

Table 3-3

Obsolescent OCI Functions

7.x OCI Routine

Equivalent or Similar Later OCI Routine

obindps(), obndra(),
obndrn(), obndrv()

OCIBindByName() or OCIBindByName2(), OCIBindByPos() or
OCIBindByPos2() (Note: additional bind calls may be necessary
for some data types)

obreak()

OCIBreak()

ocan()

none

oclose()

Note: cursors are not used in release 8.x or later

ocof(), ocon()

OCIStmtExecute() with OCI_COMMIT_ON_SUCCESS mode

ocom()

OCITransCommit()

odefin(), odefinps()

OCIDefineByPos() or OCIDefineByPos2() (Note: additional define
calls may be necessary for some data types)

odescr()

Note: schema objects are described with OCIDescribeAny(). A
describe, as used in release 7.x, most often be done by calling
OCIAttrGet() on the statement handle after SQL statement
execution.

odessp()

OCIDescribeAny()

oerhms()

OCIErrorGet()

oexec(), oexn()

OCIStmtExecute()

oexfet()

OCIStmtExecute(), OCIStmtFetch2() (Note: result set rows can
be implicitly prefetched)

ofen(), ofetch()

OCIStmtFetch2()

oflng()

none

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About Compatibility and Upgrading

Table 3-3

(Cont.) Obsolescent OCI Functions

7.x OCI Routine

Equivalent or Similar Later OCI Routine

ogetpi()

OCIStmtGetPieceInfo()

olog()

OCILogon() or OCILogon2()

ologof()

OCILogoff()

onbclr(), onbset(),
onbtst()

Note: nonblocking mode can be set or checked by calling
OCIAttrSet() or OCIAttrGet() on the server context handle or
service context handle

oopen()

Note: cursors are not used in release 8.x or later

oopt()

none

oparse()

OCIStmtPrepare2(); however, it is all local

opinit()

OCIEnvCreate()

orol()

OCITransRollback()

osetpi()

OCIStmtSetPieceInfo()

sqlld2()

SQLSvcCtxGet or SQLEnvGet

sqllda()

SQLSvcCtxGet or SQLEnvGet

odsc()

Note: see odescr() preceding

oermsg()

OCIErrorGet()

olon()

OCILogon()

orlon()

OCILogon()

oname()

Note: see odescr() preceding

osql3()

Note: see oparse() preceding

Note:
Applications using size_t to define host area (hda) that is passed to the OCI
7 calls, may crash on some platforms due to misaligned data. Hda_Def should
be used instead of size_t in that case. If the application cannot be modified,
the compiler and linker flag misalign can be used on a SPARC platform.
Refer to the demos and the following documentation for more information:
Sun Studio 12: C++ User’s Guide A.2.53 —misalign.

See Also:
•

OCI Programming Basics for information about what additional program
logic may be required before or after the new or current call is made.

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3.7.5 OCI Routines Not Supported
Some OCI routines that were available in previous versions of OCI are not supported
in the current release.
They are listed in Table 3-4.
Table 3-4

OCI Functions Not Supported

OCI Routine

Equivalent or Similar Later OCI Routine

obind()

OCIBindByName(), OCIBindByPos() (Note: additional bind
calls may be necessary for some data types)

obindn()

OCIBindByName(), OCIBindByPos() (Note: additional bind
calls may be necessary for some data types)

odfinn()

OCIDefineByPos() (Note: additional define calls may be
necessary for some data types)

odsrbn()

Note: see odescr() in Table 3-3

ologon()

OCILogon()

osql()

Note: see oparse() Table 3-3

3.8 Fault Diagnosability in OCI
This section describes the following topics:
•

About Fault Diagnosability in OCI

•

ADR Base Location

•

Using ADRCI

•

Controlling ADR Creation and Disabling Fault Diagnosability Using sqlnet.ora

3.8.1 About Fault Diagnosability in OCI
Fault diagnosability was introduced into OCI in Oracle Database 11g Release 1 (11.1).
An incident (an occurrence of a problem) on the OCI client is captured without user
intervention in the form of diagnostic data: dump files or core dump files. Up to
Release 11.2.0.1, the diagnostic data was stored in an Automatic Diagnostic
Repository (ADR) subdirectory created for the incident. For example, if a Linux or
UNIX application fails with a NULL pointer reference, then the core file is written in the
ADR home directory (if it exists) instead of the operating system directory. The ADR
subdirectory structure and a utility to deal with the output, ADR Command Interpreter
(ADRCI), are discussed in the following sections. However, beginning with Release
11.2.0.2, the diagnostic data is stored in the current directory.
An ADR home is the root directory for all diagnostic data for an instance of a particular
product such as OCI and a particular operating system user. ADR homes are grouped
under the same root directory, the ADR base.
Fault diagnosability and the ADR structure for Oracle Database are described in detail
in the discussion of managing diagnostic data in Oracle Database Administrator's
Guide.

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Fault Diagnosability in OCI

3.8.2 ADR Base Location
Describes how the location of the ADR base is determined.
The location of the ADR base is determined by OCI in the following order:
1.

For all diagnosability parameters, OCI first looks in the file oraaccess.xml. If these
parameters are not set there, then OCI looks next in sqlnet.ora (if it exists) for a
statement such as (Linux or UNIX):
ADR_BASE=/foo/adr
adr (the name of a directory) must exist and be writable by all operating system
users who execute OCI applications and want to share the same ADR base. foo
stands for a path name. The location of sqlnet.ora is given in the
directory $TNS_ADMIN (%TNS_ADMIN% on Windows). If there is no $TNS_ADMIN then the
current directory is used. If ADR_BASE is set and one sqlnet.ora is shared by all
users, then OCI stops searching when directory adr does not exist or is not
writable by the user. If ADR_BASE is not set, then OCI continues the search, testing

for the existence of certain directories.
For example, if sqlnet.ora contains the entry ADR_BASE=/home/chuck/test then the
ADR base is /home/chuck/test/oradiag_chuck and the ADR home could be
something like /home/chuck/test/oradiag_chuck/diag/clients/user_chuck/
host_4144260688_11.
2.

$ORACLE_BASE (%ORACLE_BASE% on Windows) exists. In this case, the client
subdirectory exists because it was created during installation of the database
using Oracle Universal Installer.

For example, if $ORACLE_BASE is /home/chuck/obase then the ADR base is /home/
chuck/obase and the ADR home could be similar to /home/chuck/obase/diag/
clients/user_chuck/host_4144260688_11.
3.

$ORACLE_HOME (%ORACLE_BASE% on Windows) exists. In this case, the client

subdirectory exists because it was created during installation of the database
using Oracle Universal Installer.
For example, if $ORACLE_HOME is /ade/chuck_l1/oracle then the ADR base is /ade/
chuck_l1/oracle/log and the ADR home could be similar to /ade/chuck_l1/
oracle/log/diag/clients/user_chuck/host_4144260688_11.
4.

Operating system home directory: $HOME on Linux or UNIX, or %USERPROFILE% on
Windows. On Linux or UNIX the location could be something like this for user
chuck: /home/chuck/oradiag_chuck. On Windows, a folder named Oracle is created
under C:\Documents and Settings\chuck.
For example, in an Instant Client, if $HOME is /home/chuck then the ADR base is /
home/chuck/oradiag_chuck and the ADR home could be /home/chuck/oradiag_chuck/
diag/clients/user_chuck/host_4144260688_11.

5.

On Windows, if the application is run as a service, the home directory option is
skipped.

6.

Temporary directory in the Linux or UNIX operating system: /var/tmp.
For example, in an Instant Client, if $HOME is not writable, then the ADR base
is /var/tmp/oradiag_chuck and the ADR home could be /var/tmp/oradiag_chuck/
diag/clients/user_chuck/host_4144260688_11.

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Temporary directories in the Windows operating system, searched in this order:
a.

%TMP%

b.

%TEMP%

c.

%USERPROFILE%

d.

Windows system directory

If none of these directory choices are available and writable, or the ADR base is not
created and there are no diagnostics.

See Also:
•

About Oracle Instant Client

•

Oracle Database Net Services Reference

3.8.3 Using ADRCI
ADRCI is a command-line tool that enables you to view diagnostic data within the ADR
and to package incident and problem information into a zip file for Oracle Support to
use.
You can use ADRCI interactively and from a script. A problem is a critical error in OCI
or the client. Each problem has a problem key. An incident is a single occurrence of a
problem and is identified by a unique numeric incident ID. Each incident has a problem
key that is a set of attributes: the ORA error number, error parameter values, and other
information. Two incidents have the same root cause if their problem keys match.
What follows is a launch of ADRCI in a Linux system, a use of the HELP command for
the SHOW BASE command, and then the use of the SHOW BASE command with the option PRODUCT CLIENT, which is necessary for OCI applications. The ADRCI commands are
case-insensitive. User input is shown in bold.
% adrci
ADRCI: Release 12.2.0.0.0 - Development on Wed Dec 2 18:26:29 2015
Copyright (c) 1982, 2015, Oracle. All rights reserved. ADR base = "/u01/app/oracle/
log"

adrci> help show base
Usage: SHOW BASE [-product ]
Purpose: Show the current ADR base setting.
Options:
[-product ]: This option allows users to show the
given product's ADR Base location. The current registered products are
"CLIENT" and "ADRCI".
Examples:
show base -product client
show base

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adrci> show base -product client
ADR base = "/u01/app/oracle/log"

Next, the SET BASE command is described:
adrci> help set base
Usage: SET BASE  | -product 
Purpose: Set the ADR base to use in the current ADRCI session.
If there are valid ADR homes under the base, all homes will
will be added to the current ADRCI session.
Arguments:
: It is the ADR base directory, which is a system-dependent
directory path string.
-product : This option allows users to set the
given product's ADR Base location. The current registered products are
"CLIENT" and "ADRCI".
Notes:
On platforms that use "." to signify current working directory,
it can be used as base_str.
Example:
set base /net/sttttd1/scratch/someone/view_storage/someone_v1/log
set base -product client
set base .
adrci> quit

When ADRCI is started, the default ADR base is for the rdbms server. $ORACLE_HOME is set
to "/u01/app/oracle/":
% adrci
ADRCI: Release 12.2.0.0.0 - Development on Wed Dec 2 18:26:29 2015
Copyright (c) 1982, 2015, Oracle. All rights reserved.
ADR base = "/u01/app/oracle/log"
adrci>

For OCI application incidents you must check and set the base:
adrci> show base -product client
ADR base is "/u01/app/oracle/log"
adrci> set base /home/chuck_13/oradiag_chuck

For Instant Client there is no $ORACLE_HOME, so the default base is the user's home
directory:
adrci> show base -product client
ADR base is "/home/chuck_13/oradiag_chuck"
adrci> set base /home/chuck/oradiag_chuck
adrci> show incidents
ADR Home = /home/chuck/oradiag_chuck/diag/clients/user_chuck/host_4144260688_11:
*************************************************************************
INCIDENT_ID
PROBLEM_KEY
CREATE_TIME

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------------------------------------------------------------------------1
oci 24550 [6]
2015-12-02 17:20:02.803697
-07:00
1 rows fetched
adrci>

See Also:
About Oracle Instant Client
Oracle Database Utilities for an introduction to ADRCI

3.8.4 Controlling ADR Creation and Disabling Fault Diagnosability
Using sqlnet.ora
Describes how to control ADR creation and disabling fault diagnosability using
sqlnet.ora.
To disable diagnosability, turn off diagnostics by setting the following parameters in
sqlnet.ora (the default is TRUE):
DIAG_ADR_ENABLED=FALSE
DIAG_DDE_ENABLED=FALSE

To turn off the OCI signal handler and reenable standard operating system failure
processing, place the following parameter setting in sqlnet.ora:
DIAG_SIGHANDLER_ENABLED=FALSE

As noted previously, ADR_BASE is used in sqlnet.ora to set the location of the ADR
base.
Oracle Database client contains advanced features for diagnosing issues, including
the ability to dump diagnostic information when important errors are detected. By
default, these dumps are restricted to a small subset of available information, to
ensure that application data is not dumped. However, in many installations, secure
locations for dump files may be configured, ensuring the privacy of such logs. In such
cases, it is recommended to turn on full dumps; this can greatly speed resolution of
issues. Full dumps can be enabled by adding the following line to the sqlnet.ora file
used by your Oracle Database client installation:
DIAG_RESTRICTED=FALSE

To verify that diagnosability features are working correctly:
1.

Upgrade your application to use the latest client libraries.

2.

Start your application.

3.

Check the file sqlnet.log in your application's TNS_ADMIN directory for error
messages indicating that diagnosability could not be started (normally this is due
to invalid directory names or permissions).

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See Also:
•

Oracle Database Net Services Reference for the ADR parameter
settings in sqlnet.ora

•

Oracle Database Net Services Administrator's Guide for more
information about the structure of ADR

3-29

4
OCI Programming Basics
This chapter introduces concepts and procedures involved in programming with OCI.
After reading this chapter, you should have most of the tools necessary to understand
and create a basic OCI application.
This chapter includes the following major sections:
•

Overview of OCI Program Programming

•

OCI Data Structures

•

OCI Programming Steps

•

Error Handling in OCI

•

Additional Coding Guidelines

•

About Using PL/SQL in an OCI Program

•

OCI Globalization Support

New users should pay particular attention to the information presented in this chapter,
because it forms the basis for the rest of the material presented in this guide. The
information in this chapter is supplemented by information in later chapters.

See Also:

•

Oracle Database Globalization Support Guide for a discussion of the
OCI functions that apply to a multilingual environment

•

Oracle Database Data Cartridge Developer's Guide for a discussion of
the OCI functions that apply to cartridge services

4.1 Overview of OCI Program Programming
The general goal of an OCI application is to operate on behalf of multiple users.
In an n-tiered configuration, multiple users are sending HTTP requests to the client
application. The client application may need to perform some data operations that
include exchanging data and performing data processing.
OCI uses the following basic program flow:
1.

Create the environment by initializing the OCI programming environment and
threads.

2.

Allocate necessary handles, and establish server connections and user sessions.

3.

Exchange data with the database server by executing SQL statements on the
server, and perform necessary application data processing.

4-1

Chapter 4

Overview of OCI Program Programming

4.

Execute prepared statements, or prepare a new statement for execution.

5.

Terminate user sessions and disconnect from server connections.

6.

Free handles and data structures.

Figure 4-1 illustrates the flow of steps in an OCI application. OCI Programming Steps
describes each step in more detail.

Figure 4-1

Basic OCI Program Flow

Create
Environment
Allocate Handles
and Data Structures
Connect to Server
and Begin Session
Issue SQL
and Process Data
Disconnect

Free Handles
& Data Structures

The diagram and the list of steps present a simple generalization of OCI programming
steps. Variations are possible, depending on the functionality of the program. OCI
applications that include more sophisticated functionality, such as managing multiple
sessions and transactions and using objects, require additional steps.
All OCI function calls are executed in the context of an environment. There can be
multiple environments within an OCI process. If an environment requires any processlevel initialization, then it is performed automatically.

Note:
It is possible to have multiple active connections and statements in an OCI
application.

See Also:
OCI Object-Relational Programming through Using the Object Type
Translator with OCI for information about accessing and manipulating objects

4-2

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OCI Data Structures

4.2 OCI Data Structures
Handles and descriptors are opaque data structures that are defined in OCI
applications.
Handles and descriptors can be allocated directly, through specific allocate calls, or
they can be implicitly allocated by OCI functions.

Note:
Programmers who have previously written 7.x OCI applications must become
familiar with these data structures that are used by most OCI calls.

Handles and descriptors store information pertaining to data, connections, or
application behavior. Handles are defined in more detail in the next section.
This section includes the following topics: Handles
Related Topics
•

OCI Descriptors
OCI descriptors and locators are opaque data structures that maintain dataspecific information.

4.2.1 Handles
Almost every OCI call includes in its parameter list one or more handles.
A handle is an opaque pointer to a storage area allocated by the OCI library. You use
a handle to store context or connection information, (for example, an environment or
service context handle), or it may store information about OCI functions or data (for
example, an error or describe handle). Handles can make programming easier,
because the library, rather than the application, maintains this data.
Most OCI applications must access the information stored in handles. The get and set
attribute OCI calls, OCIAttrGet() and OCIAttrSet(), access and set this information.
Table 4-1 lists the handles defined for OCI. For each handle type, the C data type and
handle type constant used to identify the handle type in OCI calls are listed.
Table 4-1

OCI Handle Types

Description

C Data Type

Handle Type Constant

OCI environment handle

OCIEnv

OCI_HTYPE_ENV

OCI error handle

OCIError

OCI_HTYPE_ERROR

OCI service context handle

OCISvcCtx

OCI_HTYPE_SVCCTX

OCI statement handle

OCIStmt

OCI_HTYPE_STMT

OCI bind handle

OCIBind

OCI_HTYPE_BIND

OCI define handle

OCIDefine

OCI_HTYPE_DEFINE

4-3

Chapter 4

OCI Data Structures

Table 4-1

(Cont.) OCI Handle Types

Description

C Data Type

Handle Type Constant

OCI describe handle

OCIDescribe

OCI_HTYPE_DESCRIBE

OCI server handle

OCIServer

OCI_HTYPE_SERVER

OCI user session handle

OCISession

OCI_HTYPE_SESSION

OCI authentication information handle

OCIAuthInfo

OCI_HTYPE_AUTHINFO

OCI connection pool handle

OCICPool

OCI_HTYPE_CPOOL

OCI session pool handle

OCISPool

OCI_HTYPE_SPOOL

OCI transaction handle

OCITrans

OCI_HTYPE_TRANS

OCI complex object retrieval (COR)
handle

OCIComplexObject

OCI_HTYPE_COMPLEXOBJECT

OCI thread handle

OCIThreadHandle

Not applicable

OCI subscription handle

OCISubscription

OCI_HTYPE_SUBSCRIPTION

OCI direct path context handle

OCIDirPathCtx

OCI_HTYPE_DIRPATH_CTX

OCI direct path function context
handle

OCIDirPathFuncCtx

OCI_HTYPE_DIRPATH_FN_CTX

OCI direct path column array handle

OCIDirPathColArray

OCI_HTYPE_DIRPATH_COLUMN_ARRAY

OCI direct path stream handle

OCIDirPathStream

OCI_HTYPE_DIRPATH_STREAM

OCI process handle

OCIProcess

OCI_HTYPE_PROC

OCI administration handle

OCIAdmin

OCI_HTYPE_ADMIN

OCI HA event handle

OCIEvent

Not applicable

OCI SODA collection handle

OCISodaColl

OCI_HTYPE_SODA_COLLECTION

OCI SODA collection cursor handle

OCISodaCollCursor

OCI_HTYPE_SODA_CURSOR

OCI SODA document handle

OCISodaDoc

OCI_HTYPE_SODA_DOCUMENT

This section includes the following topics:
•

About Allocating and Freeing Handles

•

Environment Handle

•

Error Handle

•

Service Context Handle and Associated Handles

•

Statement, Bind, and Define Handles

•

Describe Handle

•

Complex Object Retrieval Handle

•

Thread Handle

•

Subscription Handle

•

Direct Path Handles

•

Connection Pool Handle

•

Handle Attributes

•

OCI Descriptors

4-4

Chapter 4

OCI Data Structures

Related Topics
•

Handle Attributes

•

OCIAttrSet()

•

OCIAttrGet()

4.2.1.1 About Allocating and Freeing Handles
Your application allocates all handles (except the bind, define, and thread handles) for
a particular environment handle.
You pass the environment handle as one of the parameters to the handle allocation
call. The allocated handle is then specific to that particular environment.
The bind and define handles are allocated for a statement handle, and contain
information about the statement represented by that handle.

Note:
The bind and define handles are implicitly allocated by the OCI library, and
do not require user allocation.

The environment handle is allocated and initialized with a call to OCIEnvCreate() or to
OCIEnvNlsCreate(), one of which is required by all OCI applications.
All user-allocated handles are initialized using the OCI handle allocation call,
OCIHandleAlloc().
The types of handles include: session pool handle, direct path context handle, thread
handle, COR handle, subscription handle, describe handle, statement handle, service
context handle, error handle, server handle, connection pool handle, event handle,
and administration handle.
The thread handle is allocated with the OCIThreadHndInit() call.
An application must free all handles when they are no longer needed. The
OCIHandleFree() function frees all handles.

Note:
When a parent handle is freed, all child handles associated with it are also
freed and can no longer be used. For example, when a statement handle is
freed, any bind and define handles associated with it are also freed.

Handles lessen the need for global variables. Handles also make error reporting
easier. An error handle is used to return errors and diagnostic information.
Related Topics
•

OCI Demonstration Programs

•

OCIEnvCreate()

4-5

Chapter 4

OCI Data Structures

•

OCIEnvNlsCreate()

•

OCIHandleAlloc()

•

OCIThreadHndInit()

•

OCIHandleFree()

4.2.1.2 Environment Handle
The environment handle defines a context in which all OCI functions are invoked.
Each environment handle contains a memory cache that enables fast memory access.
All memory allocation under the environment handle is done from this cache. Access
to the cache is serialized if multiple threads try to allocate memory under the same
environment handle. When multiple threads share a single environment handle, they
may block on access to the cache.
The environment handle is passed as the parent parameter to the OCIHandleAlloc()
call to allocate all other handle types. Bind and define handles are allocated implicitly.

4.2.1.3 Error Handle
The error handle is passed as a parameter to most OCI calls.
The error handle maintains information about errors that occur during an OCI
operation. If an error occurs in a call, the error handle can be passed to OCIErrorGet()
to obtain additional information about the error that occurred.
Allocating the error handle is one of the first steps in an OCI application because most
OCI calls require an error handle as a parameter.
Related Topics
•

About Implementing Thread Safety
To take advantage of thread safety, an application must be running on a threadsafe operating system.

4.2.1.4 Service Context Handle and Associated Handles
A service context handle defines attributes that determine the operational context for
OCI calls to a server.
The service context handle contains three handles as its attributes, that represent a
server connection, a user session, and a transaction. These attributes are illustrated in
Figure 4-2.

Figure 4-2

Components of a Service Context
Service Context
Handle

Server
Handle

User Session
Handle

Transaction
Handle

4-6

Chapter 4

OCI Data Structures

•

A server handle identifies a connection to a database. It translates into a physical
connection in a connection-oriented transport mechanism.

•

A user session handle defines a user's roles and privileges (also known as the
user's security domain), and the operational context in which the calls execute.

•

A transaction handle defines the transaction in which the SQL operations are
performed. The transaction context includes user session state information,
including any fetch state and package instantiation.

Breaking the service context handle down in this way provides scalability and enables
programmers to create sophisticated multitiered applications and transaction
processing (TP) monitors to execute requests on behalf of multiple users on multiple
application servers and different transaction contexts.
You must allocate and initialize the service context handle with OCIHandleAlloc(),
OCILogon(), or OCILogon2() before you can use it. The service context handle is
allocated explicitly by OCIHandleAlloc(). It can be initialized using OCIAttrSet() with the
server, user session, and transaction handle. If the service context handle is allocated
implicitly using OCILogon(), it is already initialized.
Applications maintaining only a single user session for each database connection at
any time can call OCILogon() to get an initialized service context handle.
In applications requiring more complex session management, the service context
handle must be explicitly allocated, and the server and user session handles must be
explicitly set into the service context handle. OCIServerAttach() and OCISessionBegin()
calls initialize the server and user session handle respectively.
An application only defines a transaction explicitly if it is a global transaction or there
are multiple transactions active for sessions. It works correctly with the implicit
transaction created automatically by OCI when the application makes changes to the
database.

See Also:
•

OCI Support for Transactions

•

OCI Environment Initialization, and Password and Session Management
for more information about establishing a server connection and user
session

•

OCIHandleAlloc()

•

OCILogon()

•

OCILogon2()

•

OCIAttrSet()

•

OCIServerAttach()

•

OCISessionBegin()

•

OCISessionGet()

4-7

Chapter 4

OCI Data Structures

4.2.1.5 Statement, Bind, and Define Handles
A statement handle is the context that identifies a SQL or PL/SQL statement and its
associated attributes
A statement handle is shown in Figure 4-3.

Figure 4-3

Statement Handles
Statement
Handle

Define
Handle

Bind
Handle

Information about input and output bind variables is stored in bind handles. The OCI
library allocates a bind handle for each placeholder bound with the OCIBindByName() or
OCIBindByName2() or OCIBindByPos() or OCIBindByPos2() function. The user must not
allocate bind handles. They are implicitly allocated by the bind call.
Fetched data returned by a query (select statement) is converted and retrieved
according to the specifications of the define handles. The OCI library allocates a define
handle for each output variable defined with OCIDefineByPos() or OCIDefineByPos2().
The user must not allocate define handles. They are implicitly allocated by the define
call.
Bind and define handles are implicitly allocated by the OCI library, and are
transparently reused if the bind or define operation is repeated. The actual value of the
bind or define handle is needed by the application for the advanced bind or define
operations described in Binding and Defining in OCI. The handles are freed when the
statement handle is freed or when a new statement is prepared on the statement
handle. Explicitly allocating bind or define handles may lead to memory leaks.
Explicitly freeing bind or define handles may cause abnormal program termination.

See Also:
•

"Advanced Bind Operations in OCI"

•

"Advanced Define Operations in OCI"

•

OCIBindByName()

•

OCIBindByName2()

•

OCIBindByPos()

•

OCIBindByPos2()

•

OCIDefineByPos()

•

OCIDefineByPos2()

4-8

Chapter 4

OCI Data Structures

4.2.1.6 Describe Handle
The describe handle is used by the OCI describe call, OCIDescribeAny().
The OCIDescribeAny() call obtains information about schema objects in a database (for
example, functions or procedures). The call takes a describe handle as one of its
parameters, along with information about the object being described. When the call
completes, the describe handle is populated with information about the object. The
OCI application can then obtain describe information through the attributes of the
parameter descriptors.

See Also:
•

Describing Schema Metadata for more information about using the
OCIDescribeAny() function

•

OCIDescribeAny()

4.2.1.7 Complex Object Retrieval Handle
The complex object retrieval (COR) handle is used by some OCI applications that
work with objects in an Oracle database.
The complex object retrieval (COR) handle contains COR descriptors, provides
instructions for retrieving objects referenced by another object.
Related Topics
•

Complex Object Retrieval
A complex object includes its root object and its set of logically related objects
each of which are prefetched based on a given depth level.

4.2.1.8 Thread Handle
The thread handle is used in multithreaded applications.
For information about the thread handle, which is used in multithreaded applications,
see the following OCIThread Package.
Related Topics
•

OCIThread Package
The OCIThread package provides some commonly used threading primitives.

4.2.1.9 Subscription Handle
The subscription handle is used by an OCI client application that registers and
subscribes to receive notifications of database events or events in the AQ namespace.
The subscription handle encapsulates all information related to a registration from a
client.

4-9

Chapter 4

OCI Data Structures

Related Topics
•

Publish-Subscribe Notification in OCI
The publish-subscribe notification feature allows an OCI application to receive
client notifications directly, register an email address to which notifications can be
sent, register an HTTP URL to which notifications can be posted, or register a
PL/SQL procedure to be invoked on a notification.

4.2.1.10 Direct Path Handles
The direct path handles are necessary for an OCI application that uses the direct path
load engine in the Oracle database.
The direct path load interface enables the application to access the direct block
formatter of the Oracle database. Figure 4-4 shows the different kinds of direct path
handles.

Figure 4-4

Direct Path Handles
Direct Path
Context Handle

Direct Path
Column Array
Handle

Direct Path
Stream
Handle

Direct Path
Function Context
Handle

Related Topics
•

Direct Path Loading Overview
The direct path load interface enables an OCI application to access the direct path
load engine of Oracle Database to perform the functions of the SQL*Loader utility.

•

Direct Path Loading Handle Attributes

4.2.1.11 Connection Pool Handle
The connection pool handle is used for applications that pool physical connections into
virtual connections.
The connection pool handle is used for applications that pool physical connections into
virtual connections by calling specific OCI functions.
Related Topics
•

Connection Pooling in OCI
Connection pooling is the use of a group (the pool) of reusable physical
connections by several sessions to balance loads.

4.2.1.12 Handle Attributes
All OCI handles have attributes that represent data stored in that handle.
You can read handle attributes by using the attribute get call, OCIAttrGet(), and you
can change them with the attribute set call, OCIAttrSet().

4-10

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OCI Data Structures

For example, the statements in Example 4-1 set the user name in the session handle
by writing to the OCI_ATTR_USERNAME attribute:
Some OCI functions require that particular handle attributes be set before the function
is called. For example, when OCISessionBegin() is called to establish a user's login
session, the user name and password must be set in the user session handle before
the call is made.
Other OCI functions provide useful return data in handle attributes after the function
completes. For example, when OCIStmtExecute() is called to execute a SQL query,
describe information relating to the select-list items is returned in the statement
handle, as shown in Example 4-2.
This section includes the following topics:
•

SODA Collection Handle Attributes

•

SODA Document Handle Attributes

See Also:
•

The description of OCIArrayDescriptorAlloc() for an example showing
how to allocate a large number of descriptors

•

Handle and Descriptor Attributes

•

OCIAttrGet()

•

OCIAttrSet()

•

OCISessionBegin()

•

OCIStmtExecute()

Example 4-1 Using the OCI_ATTR_USERNAME Attribute to Set the User Name
in the Session Handle
text username[] = "hr";
err = OCIAttrSet ((void *) mysessp, OCI_HTYPE_SESSION, (void *)username,
(ub4) strlen((char *)username), OCI_ATTR_USERNAME, (OCIError *) myerrhp);

Example 4-2 Returning Describe Information in the Statement Handle Relating
to Select-List Items
ub4 parmcnt;
/* get the number of columns in the select list */
err = OCIAttrGet ((void *)stmhp, (ub4)OCI_HTYPE_STMT, (void *)
&parmcnt, (ub4 *) 0, (ub4)OCI_ATTR_PARAM_COUNT, errhp);

4.2.1.12.1 SODA Collection Handle Attributes
Use OCISodaColl collection handle attribute constants with OCIAttrGet() and
OCIAttrSet() calls to access SODA collection metadata.
See Oracle Database SODA for C Developer's Guide for information about each
collection handle attribute and how to get the metadata of an existing collection.
See SODA Collection Handle Attributes for more information about each collection
handle attribute.

4-11

Chapter 4

OCI Data Structures

4.2.1.12.2 SODA Document Handle Attributes
Use OCISodaDoc document handle attribute constants with OCIAttrGet() and
OCIAttrSet() calls to access SODA document metadata components.
See Oracle Database SODA for C Developer's Guide for information about each
document handle attribute and examples about how to get and set the metadata for
documents.
See SODA Document Handle Attributes for more information about each document
handle attribute.

4.2.1.13 OCI Descriptors
OCI descriptors and locators are opaque data structures that maintain data-specific
information.
Table 4-2 lists OCI descriptors, along with their C data type, and the OCI type constant
that allocates a descriptor of that type in a call to OCIDescriptorAlloc(). The
OCIDescriptorFree() function frees descriptors and locators.
Table 4-2

Descriptor Types

Description

C Data Type

OCI Type Constant

Snapshot descriptor

OCISnapshot

OCI_DTYPE_SNAP

Result set descriptor

OCIResult

OCI_DTYPE_RSET (Deprecated)

LOB data type locator

OCILobLocator

OCI_DTYPE_LOB

BFILE data type locator

OCILobLocator

OCI_DTYPE_FILE

Read-only parameter descriptor

OCIParam

OCI_DTYPE_PARAM

ROWID descriptor

OCIRowid

OCI_DTYPE_ROWID

ANSI DATE descriptor

OCIDateTime

OCI_DTYPE_DATE

TIMESTAMP descriptor

OCIDateTime

OCI_DTYPE_TIMESTAMP

TIMESTAMP WITH TIME ZONE descriptor

OCIDateTime

OCI_DTYPE_TIMESTAMP_TZ

TIMESTAMP WITH LOCAL TIME ZONE
descriptor

OCIDateTime

OCI_DTYPE_TIMESTAMP_LTZ

INTERVAL YEAR TO MONTH descriptor

OCIInterval

OCI_DTYPE_INTERVAL_YM

INTERVAL DAY TO SECOND descriptor

OCIInterval

OCI_DTYPE_INTERVAL_DS

User callback descriptor

OCIUcb

OCI_DTYPE_UCB

Distinguished names of the database
servers in a registration request

OCIServerDNs

OCI_DTYPE_SRVDN

Complex object descriptor

OCIComplexObjectComp

OCI_DTYPE_COMPLEXOBJECTCOMP

Advanced queuing enqueue options

OCIAQEnqOptions

OCI_DTYPE_AQENQ_OPTIONS

Advanced queuing dequeue options

OCIAQDeqOptions

OCI_DTYPE_AQDEQ_OPTIONS

Advanced queuing message properties

OCIAQMsgProperties

OCI_DTYPE_AQMSG_PROPERTIES

Advanced queuing agent

OCIAQAgent

OCI_DTYPE_AQAGENT

Advanced queuing notification

OCIAQNotify

OCI_DTYPE_AQNFY

Advanced queuing listen options

OCIAQListenOpts

OCI_DTYPE_AQLIS_OPTIONS

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Table 4-2

(Cont.) Descriptor Types

Description

C Data Type

OCI Type Constant

Advanced queuing message properties

OCIAQLisMsgProps

OCI_DTYPE_AQLIS_MSG_PROPERTIES

Change notification

None

OCI_DTYPE_CHDES

Table change

None

OCI_DTYPE_TABLE_CHDES

Row change

None

OCI_DTYPE_ROW_CHDES

Shard key and shard group key descriptor OCIShardkey

OCI_DTYPE_SHARD_KEY

Note:
Although there is a single C type for OCILobLocator, this locator is allocated
with a different OCI type constant for internal and external LOBs. LOB and
BFILE Locators discusses this difference.

The following list describes the main purpose of each descriptor type. The sections
that follow describe each descriptor type in more detail:
•

OCISnapshot - Used in statement execution

•

OCILobLocator - Used for LOB (OCI_DTYPE_LOB) or BFILE (OCI_DTYPE_FILE) calls

•

OCIParam - Used in describe calls

•

OCIRowid - Used for binding or defining ROWID values

•

OCIDateTime and OCIInterval - Used for datetime and interval data types

•

OCIComplexObjectComp - Used for complex object retrieval

•

OCIAQEnqOptions, OCIAQDeqOptions, OCIAQMsgProperties, OCIAQAgent - Used for

Advanced Queuing
•

OCIAQNotify - Used for publish-subscribe notification

•

OCIServerDNs - Used for LDAP-based publish-subscribe notification

This section includes the following topics:
•

Snapshot Descriptor

•

LOB and BFILE Locators

•

Parameter Descriptor

•

ROWID Descriptor

•

Date, Datetime, and Interval Descriptors

•

Complex Object Descriptor

•

Advanced Queuing Descriptors

•

User Memory Allocation

Related Topics
•

OCIDescriptorAlloc()

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•

OCIDescriptorFree()

•

OCIArrayDescriptorAlloc()

•

OCIDescriptorFree()

4.2.1.13.1 Snapshot Descriptor
The snapshot descriptor is an optional parameter to the execute call,
OCIStmtExecute().
The snapshot descriptor indicates that a query is being executed against a database
snapshot that represents the state of a database at a particular time.
Allocate a snapshot descriptor with a call to OCIDescriptorAlloc() by passing
OCI_DTYPE_SNAP as the type parameter.
Related Topics
•

OCIStmtExecute()

•

OCIDescriptorAlloc()

•

Execution Snapshots
The OCIStmtExecute() call provides the ability to ensure that multiple service
contexts operate on the same consistent snapshot of the database's committed
data.

4.2.1.13.2 LOB and BFILE Locators
A large object (LOB) is an Oracle data type that can hold binary large object (BLOB) or
character large object (CLOB) data.
In the database, an opaque data structure called a LOB locator is stored in a LOB
column of a database row, or in the place of a LOB attribute of an object. The locator
serves as a pointer to the actual LOB value, which is stored in a separate location.

Note:
Depending on your application, you may or may not want to use LOB
locators. You can use the data interface for LOBs, which does not require
LOB locators. In this interface, you can bind or define character data for CLOB
columns or RAW data for BLOB columns.

The OCI LOB locator is used to perform OCI operations against a LOB (BLOB or CLOB)
or FILE (BFILE). OCILobXXX functions take a LOB locator parameter instead of the LOB
value. OCI LOB functions do not use actual LOB data as parameters. They use the
LOB locators as parameters and operate on the LOB data referenced by them.
The LOB locator is allocated with a call to OCIDescriptorAlloc() by passing
OCI_DTYPE_LOB as the type parameter for BLOBs or CLOBs, and OCI_DTYPE_FILE for BFILEs.

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Note:
The two LOB locator types are not interchangeable. When binding or
defining a BLOB or CLOB, the application must take care that the locator is
properly allocated by using OCI_DTYPE_LOB. Similarly, when binding or defining
a BFILE, the application must be sure to allocate the locator using
OCI_DTYPE_FILE.

An OCI application can retrieve a LOB locator from the Oracle database by issuing a
SQL statement containing a LOB column or attribute as an element in the select list. In
this case, the application would first allocate the LOB locator and then use it to define
an output variable. Similarly, a LOB locator can be used as part of a bind operation to
create an association between a LOB and a placeholder in a SQL statement.
Related Topics
•

LOB and BFILE Operations
This chapter describes LOB and BFILE operations.

•

About Binding LOB Data
Oracle Database allows nonzero binds for INSERTs and UPDATEs of any size LOB.

•

About Defining LOB Data

•

OCIDescriptorAlloc()

4.2.1.13.3 Parameter Descriptor
OCI applications use parameter descriptors to obtain information about select-list
columns or schema objects.
This information is obtained through a describe operation.
The parameter descriptor is the only descriptor type that is not allocated using
OCIDescriptorAlloc(). You can obtain it only as an attribute of a describe handle,

statement handle, or through a complex object retrieval handle by specifying the
position of the parameter using an OCIParamGet() call.
Related Topics
•

OCIDescriptorAlloc()

•

OCIParamGet()

•

About Describing Select-List Items
If your OCI application is processing a query, you may need to obtain more
information about the items in the select list.

•

Describing Schema Metadata

4.2.1.13.4 ROWID Descriptor
The ROWID descriptor, OCIRowid, is used by applications that must retrieve and use
Oracle ROWIDs.
To work with a ROWID an application can define a ROWID descriptor for a rowid position in
a SQL select list, and retrieve a ROWID into the descriptor. This same descriptor can
later be bound to an input variable in an INSERT statement or WHERE clause.

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ROWIDs are also redirected into descriptors using OCIAttrGet() on the statement handle

following an execute operation.
Related Topics
•

OCIAttrGet()

4.2.1.13.5 Date, Datetime, and Interval Descriptors
The date, datetime, and interval descriptors are used by applications that use the date,
datetime, or interval data types (OCIDate, OCIDateTime, and OCIInterval).
These descriptors can be used for binding and defining, and are passed as
parameters to the functions OCIDescriptorAlloc() and OCIDescriptorFree() to allocate
and free memory.
Related Topics
•

OCIDescriptorAlloc()

•

OCIDescriptorFree()

•

Data Types

•

OCI Data Type Mapping and Manipulation Functions

4.2.1.13.6 Complex Object Descriptor
Complex object retrieval (COR) may improve application performance when dealing
with objects.
Application performance when dealing with objects may be increased using complex
object retrieval (COR).
Related Topics
•

Complex Object Retrieval
A complex object includes its root object and its set of logically related objects
each of which are prefetched based on a given depth level.

4.2.1.13.7 Advanced Queuing Descriptors
There are a number of Oracle Streams Advanced Queuing descriptors for use to
maintain data-specific information.
Oracle Streams Advanced Queuing provides message queuing as an integrated part
of Oracle Database.
Related Topics
•

OCI and Streams Advanced Queuing
OCI provides an interface to the Streams Advanced Queuing (Streams AQ)
feature. Streams AQ provides message queuing as an integrated part of Oracle
Database.

•

Publish-Subscribe Registration Functions in OCI
You can register directly to the database or register using Lightweight Directory
Access Protocol (LDAP).

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4.2.1.13.8 User Memory Allocation
The OCIDescriptorAlloc() call has an xtramem_sz parameter in its parameter list.
The xtramem_sz parameter is used to specify the amount of user memory that should
be allocated along with a descriptor or locator.
Typically, an application uses this parameter to allocate an application-defined
structure that has the same lifetime as the descriptor or locator. This structure can be
used for application bookkeeping or storing context information.
Using the xtramem_sz parameter means that the application does not need to explicitly
allocate and deallocate memory as each descriptor or locator is allocated and
deallocated. The memory is allocated along with the descriptor or locator, and freeing
the descriptor or locator (with OCIDescriptorFree()) frees the user's data structures as
well.
The OCIHandleAlloc() call has a similar parameter for allocating user memory that has
the same lifetime as the handle.
The OCIEnvCreate() and (OCIEnvInit() deprecated) calls have a similar parameter for
allocating user memory that has the same lifetime as the environment handle.
Related Topics
•

OCIDescriptorAlloc()

•

OCIDescriptorFree()

•

OCIHandleAlloc()

•

OCIEnvCreate()

•

OCIEnvInit()

4.3 OCI Programming Steps
The following sections describe in detail each of the steps in developing an OCI
application.
Some of the steps are optional. For example, you do not need to describe or define
select-list items if the statement is not a query. Application-specific processing also
occurs in between any and all of the OCI function steps.
The following sections describe the steps that are required of an OCI application:
•

OCI Environment Initialization

•

About Processing SQL Statements in OCI

•

Commit or Roll Back Operations

•

About Terminating the Application

•

Error Handling in OCI

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See Also:
•

The first sample program in OCI Demonstration Programs for an
example showing the use of OCI calls for processing SQL statements.

•

Runtime Data Allocation and Piecewise Operations in OCI for a detailed
description of the special case of dynamically providing data at run time

•

About Binding and Defining Arrays of Structures in OCI for a description
of the special considerations for operations involving arrays of structures

•

Error Handling in OCI for an outline of the steps involved in processing a
SQL statement within an OCI program

•

Overview of OCI Multithreaded Development for information about using
the OCI to write multithreaded applications

•

SQL Statements for more information about types of SQL statements

4.3.1 OCI Environment Initialization
This section describes how to initialize the OCI environment, establish a connection to
a server, and authorize a user to perform actions against the database.
First, the three main steps in initializing the OCI environment are described in the
following sections:
•

About Creating the OCI Environment

•

About Allocating Handles and Descriptors

•

Application Initialization, Connection, and Session Creation

4.3.1.1 About Creating the OCI Environment
Each OCI function call is executed in the context of an environment that is created with
the OCIEnvCreate() call.
The OCIEnvCreate() call must be invoked before any other OCI call is executed. The
only exception is the setting of a process-level attribute for the OCI shared mode.
The mode parameter of OCIEnvCreate() specifies whether the application calling the OCI
library functions can:
•

Run in a threaded environment (mode = OCI_THREADED).

•

Use objects (mode = OCI_OBJECT). Use with AQ subscription registration.

•

Use subscriptions (mode = OCI_EVENTS).

The mode can be set independently in each environment.
It is necessary to initialize in object mode if the application binds and defines objects,
or if it uses the OCI's object navigation calls. The program may also choose to use
none of these features (mode = OCI_DEFAULT) or some combination of them, separating
the options with a vertical bar. For example if mode = (OCI_THREADED | OCI_OBJECT), then
the application runs in a threaded environment and uses objects.

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You can specify user-defined memory management functions for each OCI
environment.

See Also:
•

OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for
more information about the initialization calls

•

Overview of OCI Multithreaded Development

•

OCI Object-Relational Programming , Object-Relational Data Types in
OCI, Direct Path Load Interface, Object Advanced Topics in OCI, and
Using the Object Type Translator with OCI

•

Publish-Subscribe Notification in OCI

4.3.1.2 About Allocating Handles and Descriptors
Oracle Database provides OCI functions to allocate and deallocate handles and
descriptors.
You must allocate handles using OCIHandleAlloc() before passing them into an OCI
call, unless the OCI call, such as OCIBindByPos() or OCIBindByPos2(), allocates the
handles for you.
You can allocate the types of handles listed in Table 4-1 with OCIHandleAlloc()
Depending on the functionality of your application, it must allocate some or all of these
handles.
Related Topics
•

OCIHandleAlloc()

•

OCIBindByPos()

•

OCIBindByPos2()

4.3.1.3 Application Initialization, Connection, and Session Creation
An application must call OCIEnvNlsCreate() to initialize the OCI environment handle.
Existing applications may have used OCIEnvCreate().
Following this step, the application has several options for establishing an Oracle
database connection and beginning a user session.
These methods include:
•

Single User, Single Connection

•

Client Access Through a Proxy

•

Nonproxy Multiple Sessions or Connections

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Note:
OCIEnvCreate() or OCIEnvNlsCreate() should be used instead of the
OCIInitialize() and OCIEnvInit() calls. OCIInitialize() and OCIEnvInit()

calls are supported for backward compatibility.

4.3.1.3.1 Single User, Single Connection
The single user, single connection option is the simplified logon method, which can be
used if an application maintains only a single user session for each database
connection at any time.
When an application calls OCILogon2() or OCILogon(), the OCI library initializes the
service context handle that is passed to it, and creates a connection to the specified
Oracle database for the user making the request.
Example 4-3 shows what a call to OCILogon2() looks like for a single user session with
user name hr, password hr, and database oracledb.
The parameters to this call include the service context handle (which has been
initialized), the user name, the user's password, and the name of the database that are
used to establish the connection. With the last parameter, mode, set to OCI_DEFAULT, this
call has the same effect as calling the older OCILogon(). Use OCILogon2() for any new
applications. The server and user session handles are implicitly allocated by this
function.
If an application uses this logon method, the service context, server, and user session
handles are all read-only; the application cannot switch session or transaction by
changing the appropriate attributes of the service context handle using an OCIAttrSet()
call.
An application that initializes its session and authorization using OCILogon2() must
terminate them using OCILogoff().

Note:
For simplicity in demonstrating this feature, this example does not perform
the password management techniques that a deployed system normally
uses. In a production environment, follow the Oracle Database password
management guidelines, and disable any sample accounts. See Oracle
Database Security Guide for password management guidelines and other
security recommendations.

Example 4-3

Using the OCILogon2 Call for a Single User Session

OCILogon2(envhp, errhp, &svchp, (text *)"hr", (ub4)strlen("hr"), (text *)"hr",
(ub4)strlen("hr"), (text *)"oracledb", (ub4)strlen("oracledb"),
OCI_DEFAULT);

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See Also:
Operating System Considerations for information regarding operating
systems providing facilities for spawning processes that allow child
processes to reuse state created by their parent process. This section
explains why the child process must not use the same database connection
as created by the parent.

4.3.1.3.2 Client Access Through a Proxy
Proxy authentication is a process typically employed in an environment with a middle
tier such as a firewall, in which the end user authenticates to the middle tier, which
then authenticates to the database on the user's behalf—as its proxy.
The middle tier logs in to the database as a proxy user. A proxy user can switch
identities and, after logging in to the database, switch to the end user's identity. It can
perform operations on the end user's behalf, using the authorization appropriate to that
particular end user.

Note:
In release 1 of Oracle 11g, standards for acceptable passwords were greatly
raised to increase security. Examples of passwords in this section are
incorrect. A password must contain no fewer than eight characters. See the
guidelines for securing passwords Oracle Database Security Guide for
additional information.

Proxy to database users is supported by using OCI and the ALTER USER statement,
whose BNF syntax is:
ALTER USER  GRANT CONNECT THROUGH  [AUTHENTICATION REQUIRED];

The ALTER USER statement is used once in an application. Connections can be made
multiple times afterward. In OCI, you can either use connect strings or the function
OCIAttrSet() with the parameter OCI_ATTR_PROXY_CLIENT.
Even though beginning with Oracle Database 12c Release 2 (12.2) the maximum
length of each identifier is increased to 128 bytes, the user name and proxy
combination can not exceed 250 bytes.
After a proxy switch is made, the current and connected user is the target user of the
proxy. The identity of the original user is not used for any privilege calculations. The
original user can be a local or external user.
Example 4-4 through Example 4-11 show connect strings that you can use in functions
such as OCILogon2() (set mode = OCI_DEFAULT), OCILogon(), OCISessionBegin() with
OCIAttrSet() (pass the attribute OCI_ATTR_USERNAME of the session handle), and so on.
In Example 4-4, Dilbert and Joe are two local database users. To enable Dilbert to
serve as a proxy for Joe, use the SQL statement shown in Example 4-4.

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When user name dilbert is acting on behalf of joe, use the connection string shown in
Example 4-5. (The user name dilbert has the password tiger123).
The left and right brackets "[" and "]" are entered in the connection string.
In Example 4-6, "Dilbert" and "Joe" are two local database users. The names are
case-sensitive and must be enclosed in double quotation marks. To enable "Dilbert" to
serve as a proxy for "Joe", use the SQL statement shown in Example 4-6.
When "Dilbert" is acting on behalf of "Joe", use the connection string shown in
Example 4-7. Be sure to include the double quotation marks (") characters.
When the proxy user is created as "dilbert[mybert]", use the connection string shown in
Example 4-8 to connect to the database. (The left and right brackets "[" and "]" are
entered in the connection string.)
In Example 4-9, dilbert[mybert] and joe[myjoe] are two database users that contain the
left and right bracket characters "[" and "]". If dilbert[mybert] wants to act on behalf of
joe[myjoe], Example 4-9 shows the connect statement to use.
In Example 4-10, you can set the target user name by using the ALTER USER statement.

See Also:
•

OCI_ATTR_PROXY_CLIENT

•

Oracle Database Security Guide for a discussion of proxy authentication

•

Password and Session Management

•

OCIAttrSet()

Note:
There are compatibility issues of client access through a proxy. Because this
feature was introduced in Oracle Database release 10.2, pre-10.2 clients do
not have it. If newer clients use the feature with pre-10.2 Oracle databases,
the connect fails and the client returns an error after checking the database
release level.

Example 4-4

Enabling a Local User to Serve as a Proxy for Another User

ALTER USER joe GRANT CONNECT THROUGH dilbert;

Example 4-5

Connection String to Use for the Proxy User

dilbert[joe]/tiger123@db1

Example 4-6 Preserving Case Sensitivity When Enabling a Local User to Serve
as a Proxy for Another User
ALTER USER "Joe" GRANT CONNECT THROUGH "Dilbert";

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Example 4-7

Preserving Case Sensitivity in the Connection String

"Dilbert"["Joe"]/tiger123@db1

Example 4-8

Using "dilbert[mybert]" in the Connection String

"dilbert[mybert]"/tiger123
rem the user was already created this way:
rem CREATE USER "dilbert[mybert]" IDENTIFIED BY tiger123;

Example 4-9

Using "dilbert[mybert]"["joe[myjoe]"] in the Connection String

"dilbert[mybert]"["joe[myjoe]"]/tiger123

Example 4-10

Setting the Target User Name

ALTER USER joe GRANT CONNECT THROUGH dilbert;

Then, as shown in Example 4-11, in an OCI program, use the OCIAttrSet() call to set
the attribute OCI_ATTR_PROXY_CLIENT and the proxy dilbert. In your program, use these
statements to connect multiple times.
Example 4-11 Using OCI to Set the OCI_ATTR_PROXY_CLIENT Attribute and
the Proxy dilbert
OCIAttrSet(session, OCI_HTYPE_SESSION, (void *)"dilbert",
(ub4)strlen("dilbert"), OCI_ATTR_USERNAME,
error_handle);
OCIAttrSet(session, OCI_HTYPE_SESSION, (void *)"tiger123",
(ub4)strlen("tiger123"), OCI_ATTR_PASSWORD,
error_handle);
OCIAttrSet(session, OCI_HTYPE_SESSION, (void *)"joe",
(ub4)strlen("joe"), OCI_ATTR_PROXY_CLIENT,
error_handle);

4.3.1.3.3 Nonproxy Multiple Sessions or Connections
The nonproxy multiple sessions or connections option uses explicit attach and beginsession calls to maintain multiple user sessions and connections on a database
connection.
Specific calls to attach to the Oracle database and begin sessions are:
•

OCIServerAttach() - Creates an access path to the Oracle database for OCI

operations.
•

OCISessionBegin() - Establishes a session for a user against a particular Oracle

database. This call is required for the user to execute operations on the Oracle
database.
A subsequent call to OCISessionBegin() using different service context and session
context handles logs off the previous user and causes an error. To run two
simultaneous nonmigratable sessions, a second OCISessionBegin() call must be made
with the same service context handle and a new session context handle.
These calls set up an operational environment that enables you to execute SQL and
PL/SQL statements against a database.

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See Also:
•

Connect, Authorize, and Initialize Functions

•

Session Pooling and Connection Pooling in OCI for more information
about maintaining multiple sessions, transactions, and connections

•

Client Character Set Control from OCI for the use of OCIEnvNlsCreate()

Example 4-12 demonstrates the creation and initialization of an OCI environment.
•

A server context is created and set in the service handle.

•

Then a user session handle is created and initialized using a database user name
and password.

•

For simplicity, error checking is not included.

The demonstration program cdemo81.c in the demo directory illustrates this process, with
error checking.
Example 4-12

Creating and Initializing an OCI Environment

#include 
...
main()
{
...
OCIEnv
*myenvhp;
/* the environment handle */
OCIServer *mysrvhp;
/* the server handle */
OCIError *myerrhp;
/* the error handle */
OCISession *myusrhp;
/* user session handle */
OCISvcCtx *mysvchp;
/* the service handle */
...
/* initialize the mode to be the threaded and object environment */
(void) OCIEnvCreate(&myenvhp, OCI_THREADED|OCI_OBJECT, (void *)0,
0, 0, 0, (size_t) 0, (void **)0);
/* allocate a server handle */
(void) OCIHandleAlloc ((void *)myenvhp, (void **)&mysrvhp,
OCI_HTYPE_SERVER, 0, (void **) 0);
/* allocate an error handle */
(void) OCIHandleAlloc ((void *)myenvhp, (void **)&myerrhp,
OCI_HTYPE_ERROR, 0, (void **) 0);
/* create a server context */
(void) OCIServerAttach (mysrvhp, myerrhp, (text *)"inst1_alias",
strlen ("inst1_alias"), OCI_DEFAULT);
/* allocate a service handle */
(void) OCIHandleAlloc ((void *)myenvhp, (void **)&mysvchp,
OCI_HTYPE_SVCCTX, 0, (void **) 0);
/* set the server attribute in the service context handle*/
(void) OCIAttrSet ((void *)mysvchp, OCI_HTYPE_SVCCTX,
(void *)mysrvhp, (ub4) 0, OCI_ATTR_SERVER, myerrhp);
/* allocate a user session handle */

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(void) OCIHandleAlloc ((void *)myenvhp, (void **)&myusrhp,
OCI_HTYPE_SESSION, 0, (void **) 0);
/* set user name attribute in user session handle */
(void) OCIAttrSet ((void *)myusrhp, OCI_HTYPE_SESSION,
(void *)"hr", (ub4)strlen("hr"),
OCI_ATTR_USERNAME, myerrhp);
/* set password attribute in user session handle */
(void) OCIAttrSet ((void *)myusrhp, OCI_HTYPE_SESSION,
(void *)"hr", (ub4)strlen("hr"),
OCI_ATTR_PASSWORD, myerrhp);
(void) OCISessionBegin ((void *) mysvchp, myerrhp, myusrhp,
OCI_CRED_RDBMS, OCI_DEFAULT);
/* set the user session attribute in the service context handle*/
(void) OCIAttrSet ((void *)mysvchp, OCI_HTYPE_SVCCTX,
(void *)myusrhp, (ub4) 0, OCI_ATTR_SESSION, myerrhp);
...
}

4.3.2 About Processing SQL Statements in OCI
What are the specific steps involved in processing SQL statements in OCI.
Using SQL Statements in OCI outlines the specific steps involved in processing SQL
statements in OCI.

4.3.3 Commit or Roll Back Operations
An application commits changes to the database by calling OCITransCommit().
The OCITransCommit() call uses a service context as one of its parameters. The
transaction is associated with the service context whose changes are committed. This
transaction can be explicitly created by the application or implicitly created when the
application modifies the database.

Note:
By using the OCI_COMMIT_ON_SUCCESS mode of the OCIStmtExecute() call, the
application can selectively commit transactions after each statement
execution, saving an extra round-trip.

To roll back a transaction, use the OCITransRollback() call.
If an application disconnects from Oracle Database in a way other than a normal
logoff, such as losing a network connection, and OCITransCommit() has not been called,
all active transactions are rolled back automatically.

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See Also:
•

"Service Context Handle and Associated Handles"

•

"OCI Support for Transactions"

4.3.4 About Terminating the Application
What should an application do before it terminates.
An OCI application should perform the following steps before it terminates:
1.

Delete the user session by calling OCISessionEnd() for each session.

2.

Delete access to the data sources by calling OCIServerDetach() for each source.

3.

Explicitly deallocate all handles by calling OCIHandleFree() for each handle.

4.

Delete the environment handle, which deallocates all other handles associated
with it.

Note:
When a parent OCI handle is freed, any child handles associated with it
are freed automatically
The calls to OCIServerDetach() and OCISessionEnd() are not mandatory but are
recommended. If the application terminates, and OCITransCommit() (transaction
commit) has not been called, any pending transactions are automatically rolled back.

See Also:
The first sample program in OCI Demonstration Programs for an example
showing handles being freed at the end of an application

Note:
If the application uses the simplified logon method of OCILogon2(), then a call
to OCILogoff() terminates the session, disconnects from the Oracle
database, and frees the service context and associated handles. The
application is still responsible for freeing other handles it allocated.

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4.3.5 Error Handling in OCI
OCI function calls have a set of return codes.
These OCI function call return codes are listed in Table 4-3, which indicate the
success or failure of the call, such as OCI_SUCCESS or OCI_ERROR, or provide other
information that may be required by the application, such as OCI_NEED_DATA or
OCI_STILL_EXECUTING. Most OCI calls return one of these codes.
To verify that the connection to the server is not terminated by the OCI_ERROR, an
application can check the value of the attribute OCI_ATTR_SERVER_STATUS in the server
handle. If the value of the attribute is OCI_SERVER_NOT_CONNECTED, then the connection to
the server and the user session must be reestablished.

See Also:

Table 4-3

•

"Functions Returning Other Values" for exceptions

•

"OCIErrorGet()" for complete details and an example of usage

•

"Server Handle Attributes"

OCI Return Codes

OCI Return Code

Value

Description

OCI_SUCCESS

0

The function completed successfully.

OCI_SUCCESS_WITH_INFO

1

The function completed successfully; a call to OCIErrorGet()
returns additional diagnostic information. This may include warnings.

OCI_NO_DATA

100

The function completed, and there is no further data.

OCI_ERROR

-1

The function failed; a call to OCIErrorGet() returns additional
information.

OCI_INVALID_HANDLE

-2

An invalid handle was passed as a parameter or a user callback was
passed an invalid handle or invalid context. No further diagnostics
are available.

OCI_NEED_DATA

99

The application must provide runtime data.

OCI_STILL_EXECUTING

-3123

The service context was established in nonblocking mode, and the
current operation could not be completed immediately. The
operation must be called again to complete. OCIErrorGet() returns
ORA-03123 as the error code.

OCI_CONTINUE

-24200

This code is returned only from a callback function. It indicates that
the callback function wants the OCI library to resume its normal
processing.

OCI_ROWCBK_DONE

-24201

This code is returned only from a callback function. It indicates that
the callback function is done with the user row callback.

If the return code indicates that an error has occurred, the application can retrieve
error codes and messages specific to Oracle Database by calling OCIErrorGet(). One
of the parameters to OCIErrorGet() is the error handle passed to the call that caused
the error.

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Note:
Multiple diagnostic records can be retrieved by calling OCIErrorGet()
repeatedly until there are no more records (OCI_NO_DATA is returned).
OCIErrorGet() returns at most a single diagnostic record.

This section includes the following topics:
•

Return and Error Codes for Data

•

Functions Returning Other Values

4.3.5.1 Return and Error Codes for Data
The OCI return code, error number, indicator variable, and column return code are
specified when the data fetched is normal, null, or truncated.
In Table 4-4, the OCI return code, error number, indicator variable, and column return
code are specified when the data fetched is normal, null, or truncated.

See Also:
"Indicator Variables"

Table 4-4

Return and Error Codes

State of Data

Return Code

Indicator - Not provided

Indicator - Provided

Not null or
truncated

Not provided

OCI_SUCCESS

OCI_SUCCESS

Error = 0

Error = 0
Indicator = 0

Not null or
truncated

Provided

OCI_SUCCESS

OCI_SUCCESS

Error = 0

Error = 0

Return code = 0

Indicator = 0
Return code = 0

Null data

Not provided

OCI_ERROR

OCI_SUCCESS

Error = 1405

Error = 0
Indicator = -1

Null data

Provided

OCI_ERROR

OCI_SUCCESS

Error = 1405

Error = 0

Return code = 1405

Indicator = -1
Return code = 1405

Truncated data

Not provided

OCI_ERROR

OCI_ERROR

Error = 1406

Error = 1406
Indicator = data_len

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Table 4-4

(Cont.) Return and Error Codes

State of Data

Return Code

Indicator - Not provided

Indicator - Provided

Truncated data

Provided

OCI_SUCCESS_WITH_INFO

OCI_SUCCESS_WITH_INFO

Error = 24345

Error = 24345

Return code = 1405

Indicator = data_len
Return code = 1406

For truncated data, data_len is the actual length of the data that has been truncated if
this length is less than or equal to SB2MAXVAL. Otherwise, the indicator is set to -2.

4.3.5.2 Functions Returning Other Values
Some functions return values other than the OCI error codes.
These other OCI error codes are listed in Table 4-3. When you use these functions, be
aware that they return values directly from the function call, rather than through an OUT
parameter. More detailed information about each function and its return values is listed
in the reference chapters.

4.4 Additional Coding Guidelines
This section explains some additional issues when coding OCI applications.
This section includes the following topics:
•

Operating System Considerations

•

Parameter Types

•

Inserting Nulls into a Column

•

Indicator Variables

•

About Canceling Calls

•

Positioned Updates and Deletes

•

Reserved Words

•

Polling Mode Operations in OCI

•

Nonblocking Mode in OCI

•

Setting Blocking Modes

•

Canceling a Nonblocking Call

4.4.1 Operating System Considerations
Operating systems may provide facilities for spawning processes that allow child
processes to reuse the state created by their parent process.
After spawning a child process, the child process must not use the same database
connection as created by the parent. Any attempt on behalf of the child process to use
the same database connection as the parent may cause undesired connection

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interference and result in intermittent ORA-03137 errors, because Oracle Net expects
only one user process to be using a connection to the database.
Where multiple, concurrent connections are required, consider using threads if your
platform supports a threads package. Concurrent connections are supported in either
single-threaded or multithreaded applications. For better performance with many
concurrently opened connections, consider pooling them.

See Also:
•

Overview of OCI Multithreaded Development

•

OCIThread Package

•

Session Pooling in OCI

•

When to Use Connection Pooling, Session Pooling, or Neither

4.4.2 Parameter Types
OCI functions take a variety of different types of parameters, including integers,
handles, and character strings.
Special considerations must be taken into account for some types of parameters, as
described in the following sections:
•

Address Parameters

•

Integer Parameters

•

Character String Parameters

This section includes the following topics:

See Also:
Connect, Authorize, and Initialize Functions for more information about
parameter data types and parameter passing conventions

4.4.2.1 Address Parameters
Address parameters are used to pass the address of the variable to Oracle Database.
You should be careful when developing in C, because it normally passes scalar
parameters by value.

4.4.2.2 Integer Parameters
Binary integer and short binary integer parameters are numbers whose size is systemdependent.
See Oracle Database documentation that is specific to your operating system for the
size of these integers on your system.

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4.4.2.3 Character String Parameters
Character strings are a special type of address parameter.
Each OCI routine that enables a character string to be passed as a parameter also
has a string length parameter. The length parameter should be set to the length of the
string.

Note:
Unlike earlier versions of OCI, you do not pass -1 for the string length
parameter of a null-terminated string.

4.4.3 Inserting Nulls into a Column
How to insert a null into a database column.
You can insert a null into a database column in several ways.
•

One method is to use a literal NULL in the text of an INSERT or UPDATE statement. For
example, the SQL statement makes the ENAME column NULL.
INSERT INTO emp1 (ename, empno, deptno)
VALUES (NULL, 8010, 20)

•

Use indicator variables in the OCI bind call.

•

Insert a NULL to set both the buffer length and maximum length parameters to zero
on a bind call.

Note:
Following the SQL standard requirements, Oracle Database returns an
error if an attempt is made to fetch a null select-list item into a variable
that does not have an associated indicator variable specified in the
define call.
Related Topics
•

Indicator Variables
Each bind and define OCI call has a parameter that associates an indicator
variable, or an array of indicator variables, with a DML statement, a PL/SQL
statement, or a query.

4.4.4 Indicator Variables
Each bind and define OCI call has a parameter that associates an indicator variable,
or an array of indicator variables, with a DML statement, a PL/SQL statement, or a
query.
The C language does not have the concept of null values; therefore, you associate
indicator variables with input variables to specify whether the associated placeholder is

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a NULL. When data is passed to an Oracle database, the values of these indicator
variables determine whether a NULL is assigned to a database field.
For output variables, indicator variables determine whether the value returned from
Oracle is a NULL or a truncated value. For a NULL fetch in an OCIStmtFetch2() call or a
truncation in an OCIStmtExecute() call, the OCI call returns OCI_SUCCESS_WITH_INFO. The
output indicator variable is set.
The data type of indicator variables is sb2. For arrays of indicator variables, the
individual array elements should be of type sb2.
This section includes the following topics:
•

Input

•

Output

•

Indicator Variables for Named Data Types and REFs

4.4.4.1 Input
What values can be assigned to an indicator variable.
For input host variables, the OCI application can assign the following values to an
indicator variable:
Input Indicator Value

Action Taken by Oracle Database

-1

Oracle Database assigns a NULL to the column, ignoring the value
of the input variable.

>=0

Oracle Database assigns the value of the input variable to the
column.

4.4.4.2 Output
What values can be assigned to an indicator variable.
On output, Oracle Database can assign the following values to an indicator variable:
Output Indicator Value

Meaning

-2

The length of the item is greater than the length of the output
variable; the item has been truncated. Additionally, the original
length is longer than the maximum data length that can be
returned in the sb2 indicator variable.

-1

The selected value is null, and the value of the output variable is
unchanged.

0

Oracle Database assigned an intact value to the host variable.

>0

The length of the item is greater than the length of the output
variable; the item has been truncated. The positive value returned
in the indicator variable is the actual length before truncation.

4.4.4.3 Indicator Variables for Named Data Types and REFs
Indicator variables for most data types introduced after release 8.0 behave as
described earlier.

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The only exception is SQLT_NTY (a named data type). For data of type SQLT_NTY,
the indicator variable must be a pointer to an indicator structure. Data of type
SQLT_REF uses a standard scalar indicator, just like other variable types.
When database types are translated into C struct representations using the Object
Type Translator (OTT), a null indicator structure is generated for each object type. This
structure includes an atomic null indicator, plus indicators for each object attribute.

See Also:
•

Documentation for the OTT in Using the Object Type Translator with
OCI, and NULL Indicator Structure for information about NULL indicator
structures

•

Descriptions of OCIBindByName() and OCIBindByPos() in Bind, Define, and
Describe Functions, and the sections Information for Named Data Type
and REF Binds, and Information for Named Data Type and REF Defines,
and PL/SQL OUT Binds for more information about setting indicator
parameters for named data types and REFs

4.4.5 About Canceling Calls
How do you cancel long-running or repeated OCI calls.
On most operating systems, you can cancel long-running or repeated OCI calls by
entering the operating system's interrupt character (usually Control+C) from the
keyboard.

Note:
This is not to be confused with canceling a cursor, which is accomplished by
calling OCIStmtFetch2() with the nrows parameter set to zero.

When you cancel the long-running or repeated call using the operating system
interrupt, the error code ORA-01013 ("user requested cancel of current operation") is
returned.
When given a particular service context pointer or server context pointer, the
OCIBreak() function performs an immediate (asynchronous) stop of any currently
executing OCI function associated with the server. It is normally used to stop a longrunning OCI call being processed on the server. The OCIReset() function is necessary
to perform a protocol synchronization on a nonblocking connection after an OCI
application stops a function with OCIBreak().

Note:
OCIBreak() works on Windows systems.

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The status of potentially long-running calls can be monitored using nonblocking calls.
Use multithreading for new applications.

See Also:
•

Overview of OCI Multithreaded Development

•

OCIThread Package

4.4.6 Positioned Updates and Deletes
You can use the ROWID associated with a SELECT...FOR UPDATE OF... statement in a later
UPDATE or DELETE statement.
The ROWID is retrieved by calling OCIAttrGet() on the statement handle to retrieve the
handle's OCI_ATTR_ROWID attribute.
For example, consider a SQL statement such as the following:
SELECT ename FROM emp1 WHERE empno = 7499 FOR UPDATE OF sal

When the fetch is performed, the ROWID attribute in the handle contains the row
identifier of the selected row. You can retrieve the ROWID into a buffer in your program
by calling OCIAttrGet() as follows:
OCIRowid *rowid; /* the rowid in opaque format */
/* allocate descriptor with OCIDescriptorAlloc() */
status = OCIDescriptorAlloc ((void *) envhp, (void **) &rowid,
(ub4) OCI_DTYPE_ROWID, (size_t) 0, (void **) 0);
status = OCIAttrGet ((void *) mystmtp, OCI_HTYPE_STMT,
(void *) rowid, (ub4 *) 0, OCI_ATTR_ROWID, (OCIError *) myerrhp);

You can then use the saved ROWID in a DELETE or UPDATE statement. For example, if
rowid is the buffer in which the row identifier has been saved, you can later process a
SQL statement such as the following by binding the new salary to the :1 placeholder
and rowid to the :2 placeholder.
UPDATE emp1 SET sal = :1 WHERE rowid = :2

Be sure to use data type code 104 (ROWID descriptor, see Table 5-2) when binding
rowid to :2.

By using prefetching, you can select an array of ROWIDs for use in subsequent batch
updates.

See Also:
•

UROWID and DATE for more information about ROWIDs

•

External Data Types for a table of external data types and codes

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4.4.7 Reserved Words
Some words are reserved by Oracle.
That is, some reserved words have a special meaning to Oracle and cannot be
redefined. For this reason, you cannot use them to name database objects such as
columns, tables, or indexes.
This section includes the following topic: Oracle Reserved Namespaces

See Also:
Oracle Database SQL Language Reference and Oracle Database PL/SQL
Language Reference to view the lists of the Oracle keywords or reserved
words for SQL and PL/SQL

4.4.7.1 Oracle Reserved Namespaces
What namespaces are reserved by Oracle. For a complete list of functions within a
particular namespace, refer to the document that corresponds to the appropriate
Oracle library.
Table 4-5 contains a list of namespaces that are reserved by Oracle. The initial
characters of function names in Oracle libraries are restricted to the character strings
in this list. Because of potential name conflicts, do not use function names that begin
with these characters.
Table 4-5

Oracle Reserved Namespaces

Namespace

Library

XA

External functions for XA applications only

SQ

External SQLLIB functions used by Oracle Precompiler and
SQL*Module applications

O, OCI

External OCI functions internal OCI functions

UPI, KP

Function names from the Oracle UPI layer

NA

Oracle Net Native Services Product

NC

Oracle Net RPC Project

ND

Oracle Net Directory

NL

Oracle Net Network Library Layer

NM

Oracle Net Management Project

NR

Oracle Net Interchange

NS

Oracle Net Transparent Network Service

NT

Oracle Net Drivers

NZ

Oracle Net Security Service

OSN

Oracle Net V1

TTC

Oracle Net Two Task

GEN, L, ORA

Core library functions

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Table 4-5

(Cont.) Oracle Reserved Namespaces

Namespace

Library

LI, LM, LX

Function names from the Oracle Globalization Support layer

S

Function names from system-dependent libraries

KO

Kernel Objects

4.4.8 Polling Mode Operations in OCI
OCI has calls that poll for completion.
Examples of such polling mode calls are:
•
•

OCI calls in nonblocking mode
OCI calls that operate on LOB data in pieces such as OCILobRead2() and
OCILobWrite2()

•

OCIStmtExecute() and OCIStmtFetch2() when used with OCIStmtSetPieceInfo() and
OCIStmtGetPieceInfo()

In such cases, OCI requires that the application ensure that the same OCI call is
repeated on the connection and nothing else is done on the connection in the interim.
Performing any other OCI call on such a connection (when OCI has handed control
back to the caller) can result in unexpected behavior.
Hence, with such polling mode OCI calls, the caller must ensure that the same call is
repeated on the connection and that nothing else is done until the call completes.
OCIBreak() and OCIReset() are exceptions to the rule. These calls are allowed so that
the caller can stop an OCI call that has been started.

4.4.9 Nonblocking Mode in OCI
OCI provides the ability to establish a server connection in blocking mode or
nonblocking mode.

Note:
Because nonblocking mode requires the caller to repeat the same call until it
completes, it increases CPU usage. Instead, use multithreaded mode.

See Also:
•

Overview of OCI Multithreaded Development

•

OCIThread Package

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When a connection is made in blocking mode, an OCI call returns control to an OCI
client application only when the call completes, either successfully or in error. With the
nonblocking mode, control is immediately returned to the OCI program if the call could
not complete, and the call returns a value of OCI_STILL_EXECUTING.
In nonblocking mode, an application must test the return code of each OCI function to
see if it returns OCI_STILL_EXECUTING. If it does, the OCI client can continue to process
program logic while waiting to retry the OCI call to the server. This mode is particularly
useful in graphical user interface (GUI) applications, real-time applications, and in
distributed environments.
The nonblocking mode is not interrupt-driven. Rather, it is based on a polling
paradigm, which means that the client application must check whether the pending call
is finished at the server by executing the call again with the exact same parameters.
The following features and functions are not supported in nonblocking mode:
•

Direct Path Load

•

LOB buffering

•

Objects

•

Query cache

•

Scrollable cursors

•

Transparent application failover (TAF)

•

OCIAQEnqArray()

•

OCIAQDeqArray()

•

OCIDescribeAny()

•

OCILobArrayRead()

•

OCILobArrayWrite()

•

OCITransStart()

•

OCITransDetach()

4.4.10 Setting Blocking Modes
You can modify or check an application's blocking status by calling OCIAttrSet() to set
the status, or OCIAttrGet() to read the status on the server context handle with the
attrtype parameter set to OCI_ATTR_NONBLOCKING_MODE.
You must set this OCI_ATTR_NONBLOCKING_MODE attribute only after OCISessionBegin() or
OCILogon2() has been called. Otherwise, an error is returned.

Note:
Only functions that have a server context or a service context handle as a
parameter can return OCI_STILL_EXECUTING.

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See Also:
Server Handle Attributes

4.4.11 Canceling a Nonblocking Call
You can cancel a long-running OCI call by using the OCIBreak() function while the OCI
call is in progress.
You must then issue an OCIReset() call to reset the asynchronous operation and
protocol.

4.5 About Using PL/SQL in an OCI Program
PL/SQL is Oracle's procedural extension to the SQL language.
PL/SQL supports tasks that are more complicated than simple queries and SQL data
manipulation language (DML) statements. PL/SQL enables you to group some
constructs into a single block and execute it as a unit. These constructs include:
•

One or more SQL statements

•

Variable declarations

•

Assignment statements

•

Procedural control statements such as IF...THEN...ELSE statements and loops

•

Exception handling

You can use PL/SQL blocks in your OCI program to perform the following operations:
•

Call Oracle stored procedures and stored functions

•

Combine procedural control statements with several SQL statements, to be
executed as a unit

•

Access special PL/SQL features such as tables, CURSOR FOR loops, and exception
handling

•

Use cursor variables

•

Operate on objects in a server

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Note:
–

Although OCI can only directly process anonymous blocks, and not
named packages or procedures, you can always put the package or
procedure call within an anonymous block and process that block.

–

Note that all OUT variables must be initialized to NULL (through an
indicator of -1, or an actual length of 0) before a PL/SQL begin-end
block can be executed in OCI.

–

OCI does not support the PL/SQL RECORD data type.

–

When binding a PL/SQL VARCHAR2 variable in OCI, the maximum
size of the bind variable is 32767 bytes, because of the overhead of
control structures.

Note:
When you write PL/SQL code, it is important to remember that the parser
treats everything between a pair of hyphens"--" and a carriage return
character as a comment. So if comments are indicated on each line by
"--", the C compiler can concatenate all lines in a PL/SQL block into a
single line without putting a carriage return "\n" for each line. In this
particular case, the parser fails to extract the PL/SQL code of a line if the
previous line ends with a comment. To avoid the problem, the
programmer should put "\n" after each "--" comment to ensure that the
comment ends there.

See Also:
Oracle Database PL/SQL Language Reference for information about
coding PL/SQL blocks

4.6 OCI Globalization Support
The following sections introduce OCI functions that can be used for globalization
purposes, such as deriving locale information, manipulating strings, character set
conversion, and OCI messaging.
These functions are also described in detail in other chapters of this guide because
they have multiple purposes and functionality.
This section includes the following topics:
•

Client Character Set Control from OCI

•

Character Control and OCI Interfaces

•

Character-Length Semantics Support in Describe Operations

•

Character Set Support in OCI

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•

Controlling Language and Territory in OCI

•

Other OCI Globalization Support Functions

•

About Getting Locale Information in OCI

•

About OCI and the BOM (Byte Order Mark)

•

About Manipulating Strings in OCI

•

About Converting Character Sets in OCI

•

OCI Messaging Functions

•

lmsgen Utility

4.6.1 Client Character Set Control from OCI
The function OCIEnvNlsCreate() enables you to set character set information in
applications independently from NLS_LANG and NLS_NCHAR settings.
OCI_UTF16ID cannot be set from NLS_LANG or NLS_NCHAR and must be set using
OCIEnvNlsCreate(). One application can have several environment handles initialized

within the same system environment using different client-side character set IDs and
national character set IDs. For example:
OCIEnvNlsCreate(OCIEnv **envhpp, ..., csid, ncsid);

In this example, csid is the value for the character set ID for the parameter charset,
and ncsid is the value for the national character set ID for the parameter ncharset.
Either can be 0 or OCI_UTF16ID. If both are 0, this is equivalent to using OCIEnvCreate()
instead. The other arguments are the same as for the OCIEnvCreate() call.
Any Oracle character set ID, except AL16UTF16, can be specified through the
OCIEnvNlsCtrate() function to specify the encoding of metadata, SQL CHAR data, and
SQL NCHAR data.
You can retrieve character sets in NLS_LANG and NLS_NCHAR through another function,
OCINlsEnvironmentVariableGet().

See Also:
•

OCIEnvNlsCreate()

•

About Setting Client Character Sets in OCI for a pseudocode fragment
that illustrates a sample usage of these calls

4.6.2 Character Control and OCI Interfaces
How is character control performed by OCI interfaces.
The OCINlsGetInfo() function returns information about any character set, including
OCI_UTF16ID if this value has been used in OCIEnvNlsCreate().
The OCIAttrGet() function returns the character set ID and national character set ID
that were passed into OCIEnvNlsCreate(). This is used to get OCI_ATTR_ENV_CHARSET_ID
and OCI_ATTR_ENV_NCHARSET_ID. This includes the value OCI_UTF16ID.

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If both charset and ncharset parameters were set to 0 by OCIEnvNlsCreate(), the
character set IDs in NLS_LANG and NLS_NCHAR are returned.
The OCIAttrSet() function sets character IDs as the defaults if OCI_ATTR_CHARSET_FORM is
reset through this function. The eligible character set IDs include OCI_UTF16ID if
OCIEnvNlsCreate() is passed as charset or ncharset.
The OCIBindByName() or OCIBindByName2() and OCIBindByPos() or OCIBindByPos2()
functions bind variables with the default character set in the OCIEnvNlsCreate() call,
including OCI_UTF16ID. The actual length and the returned length are always in bytes if
OCIEnvNlsCreate() is used.
The OCIDefineByPos() or OCIDefineByPos2() function defines variables with the value of
charset in OCIEnvNlsCreate(), including OCI_UTF16ID, as the default. The actual length
and returned length are always in bytes if OCIEnvNlsCreate() is used. This behavior for
bind and define handles is different from that when OCIEnvCreate() is used and
OCI_UTF16ID is the character set ID for the bind and define handles.

4.6.3 Character-Length Semantics in OCI
OCI works as a translator between server and client, and passes around character
information for constraint checking.
There are two kinds of character sets: variable-width and fixed-width. (A single-byte
character set is a special case of a fixed-width character set where each byte stands
for one character.)
For fixed-width character sets, constraint checking is easier, as the number of bytes is
equal to a multiple of the number of characters. Therefore, scanning of the entire string
is not needed to determine the number of characters for fixed-width character sets.
However, for variable-width character sets, complete scanning is needed to determine
the number of characters in a string.

4.6.4 Character Set Support in OCI
How does OCI support character sets.
See Character-Length Semantics Support in Describe Operations and Character
Conversion in OCI Binding and Defining for a complete discussion of character set
support in OCI.

4.6.5 Controlling Language and Territory in OCI
The NLS language and territory can also be set programmatically using the attributes
OCI_ATTR_ENV_NLS_LANGUAGE and OCI_ATTR_ENV_NLS_TERRITORY on OCI environment

handle.
See the following attributes for more details on their usage. These attributes will be
effective for the database sessions created from that environment handle after the
attributes have been set.
•

OCI_ATTR_ENV_NLS_LANGUAGE

•

OCI_ATTR_ENV_NLS_TERRITORY

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4.6.6 Other OCI Globalization Support Functions
Many globalization support functions accept either the environment handle or the user
session handle.
The OCI environment handle is associated with the client NLS environment variables.
This environment does not change when ALTER SESSION statements are issued to the
server. The character set associated with the environment handle is the client
character set. The OCI session handle (returned by OCISessionBegin()) is associated
with the server session environment. The NLS settings change when the session
environment is modified with an ALTER SESSION statement. The character set associated
with the session handle is the database character set.
Note that the OCI session handle does not have NLS settings associated with it until
the first transaction begins in the session. SELECT statements do not begin a
transaction.

See Also:
•

OCI Globalization Support Functions

•

Oracle Database Globalization Support Guide for information about OCI
programming with Unicode

4.6.7 About Getting Locale Information in OCI
An Oracle Database locale consists of language, territory, and character set
definitions.
The locale determines conventions such as day and month names, as well as date,
time, number, and currency formats. A globalized application follows a user's locale
setting and cultural conventions. For example, when the locale is set to German, users
expect to see day and month names in German.

See Also:
•

OCI Locale Functions

•

OCINlsEnvironmentVariableGet()

You can retrieve the following information with the OCINlsGetInfo() function:
•

Days of the week (translated)

•

Abbreviated days of the week (translated)

•

Month names (translated)

•

Abbreviated month names (translated)

•

Yes/no (translated)

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•

AM/PM (translated)

•

AD/BC (translated)

•

Numeric format

•

Debit/credit

•

Date format

•

Currency formats

•

Default language

•

Default territory

•

Default character set

•

Default linguistic sort

•

Default calendar

The code in Example 4-13 retrieves locale information and checks for errors.
Example 4-13

Getting Locale Information in OCI

sword MyPrintLinguisticName(envhp, errhp)
OCIEnv *envhp;
OCIError *errhp;
{
OraText infoBuf[OCI_NLS_MAXBUFSZ];
sword ret;
ret = OCINlsGetInfo(envhp,
/* environment handle
errhp,
/* error handle
infoBuf,
/* destination buffer
(size_t) OCI_NLS_MAXBUFSZ,
/* buffer size
(ub2) OCI_NLS_LINGUISTIC_NAME);
/* item

*/
*/
*/
*/
*/

if (ret != OCI_SUCCESS)
{
checkerr(errhp, ret, OCI_HTYPE_ERROR);
ret = OCI_ERROR;
}
else
{
printf("NLS linguistic: %s\n", infoBuf);
}
return(ret);
}

4.6.8 About OCI and the BOM (Byte Order Mark)
OCI does not support nor handle the BOM (byte order mark) and assumes that the
byte order is native to the machine on which your application is executing.
Your OCI application must not pass a string containing a BOM expecting that OCI can
detect the encoding of the string. Your OCI application must remove the BOM if it
exists in the string being passed in and ensure that it is in the encoding the OCI
function expects.

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4.6.9 About Manipulating Strings in OCI
Multibyte strings and wide-character strings are supported for string manipulation.
Multibyte strings are encoded in native Oracle character sets. Functions that operate
on multibyte strings take the string as a whole unit with the length of the string
calculated in bytes. Wide-character string (wchar) functions provide more flexibility in
string manipulation. They support character-based and string-based operations where
the length the string calculated in characters.
The wide-character data type, OCIWchar, is Oracle-specific and should not be confused
with the wchar_t data type defined by the ANSI/ISO C standard. The Oracle widecharacter data type is always 4 bytes in all operating systems, whereas the size of
wchar_t depends on the implementation and the operating system. The Oracle widecharacter data type normalizes multibyte characters so that they have a uniform fixed
width for easy processing. This guarantees no data loss for round-trip conversion
between the Oracle wide-character set and the native character set.
String manipulation can be classified into the following categories:
•

Conversion of strings between multibyte and wide character

•

Character classifications

•

Case conversion

•

Calculations of display length

•

General string manipulation, such as comparison, concatenation, and searching

See Also:
OCI String Manipulation Functions
Example 4-14 shows a simple case of manipulating strings.
The OCI character classification functions are described in detail in OCI Character
Classification Functions.
Example 4-15 shows how to classify characters in OCI.
Example 4-14

Basic String Manipulation in OCI

size_t MyConvertMultiByteToWideChar(envhp, dstBuf, dstSize, srcStr)
OCIEnv
*envhp;
OCIWchar *dstBuf;
size_t
dstSize;
OraText
*srcStr;
/* null terminated source string */
{
sword ret;
size_t dstLen = 0;
size_t srcLen;
/* get length of source string */
srcLen = OCIMultiByteStrlen(envhp, srcStr);
ret = OCIMultiByteInSizeToWideChar(envhp,
dstBuf,

/* environment handle */
/* destination buffer */

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dstSize,
srcStr,
srcLen,
&dstLen);

/* destination buffer size
/* source string
/* length of source string
/* pointer to destination length

*/
*/
*/
*/

if (ret != OCI_SUCCESS)
{
checkerr(envhp, ret, OCI_HTYPE_ENV);
}
return(dstLen);
}

Example 4-15

Classifying Characters in OCI

boolean MyIsNumberWideCharString(envhp, srcStr)
OCIEnv *envhp;
OCIWchar *srcStr;
/* wide char source string */
{
OCIWchar *pstr = srcStr;
/* define and init pointer */
boolean status = TRUE;
/* define and initialize status variable */
/* Check input */
if (pstr == (OCIWchar*) NULL)
return(FALSE);

if (*pstr == (OCIWchar) NULL)
return(FALSE);
/* check each character for digit */
do
{
if (OCIWideCharIsDigit(envhp, *pstr) != TRUE)
{
status = FALSE;
break;
/* non-decimal digit character */
}
} while ( *++pstr != (OCIWchar) NULL);
return(status);
}

4.6.10 About Converting Character Sets in OCI
Conversion between Oracle character sets and Unicode (16-bit, fixed-width Unicode
encoding) is supported.
Replacement characters are used if a character has no mapping from Unicode to the
Oracle character set. Therefore, conversion back to the original character set is not
always possible without data loss.
Character set conversion functions involving Unicode character sets require data bind
and define buffers to be aligned at a ub2 address or an error is raised.
Example 4-16 shows a simple conversion into Unicode.

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See Also:
OCI Character Set Conversion Functions

Example 4-16

Converting Character Sets in OCI

/* Example of Converting Character Sets in OCI
--------------------------------------------*/
size_t MyConvertMultiByteToUnicode(envhp, errhp, dstBuf, dstSize, srcStr)
OCIEnv *envhp;
OCIError *errhp;
ub2 *dstBuf;
size_t dstSize;
OraText *srcStr;
{
size_t dstLen = 0;
size_t srcLen = 0;
OraText tb[OCI_NLS_MAXBUFSZ]; /* NLS info buffer */
ub2
cid;
/* OCIEnv character set ID */
/* get OCIEnv character set */
checkerr(errhp, OCINlsGetInfo(envhp, errhp, tb, sizeof(tb),
OCI_NLS_CHARACTER_SET));
cid = OCINlsCharSetNameToId(envhp, tb);
if (cid == OCI_UTF16ID)
{
ub2
*srcStrUb2 = (ub2*)srcStr;
while (*srcStrUb2++) ++srcLen;
srcLen *= sizeof(ub2);
}
else
srcLen = OCIMultiByteStrlen(envhp, srcStr);
checkerr(errhp,
OCINlsCharSetConvert(
envhp,
/* environment handle */
errhp,
/* error handle */
OCI_UTF16ID, /* Unicode character set ID */
dstBuf,
/* destination buffer */
dstSize,
/* size of destination buffer */
cid,
/* OCIEnv character set ID */
srcStr,
/* source string */
srcLen,
/* length of source string */
&dstLen)); /* pointer to destination length */
return dstLen/sizeof(ub2);
}

4.6.11 OCI Messaging Functions
The user message API provides a simple interface for cartridge developers to retrieve
their own messages and Oracle Database messages.
Example 4-17 creates a message handle, initializes it to retrieve messages from
impus.msg, retrieves message number 128, and closes the message handle. It

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assumes that OCI environment handles, OCI session handles, and the product,
facility, and cache size have been initialized properly.
Example 4-17

Retrieving a Message from a Text Message File

OCIMsg msghnd;
/* message handle */
/* initialize a message handle for retrieving messages from impus.msg*/
err = OCIMessageOpen(hndl,errhp, &msghnd, prod,fac,OCI_DURATION_SESSION);
if (err != OCI_SUCCESS)
/* error handling */
...
/* retrieve the message with message number = 128 */
msgptr = OCIMessageGet(msghnd, 128, msgbuf, sizeof(msgbuf));
/* do something with the message, such as display it */
...
/* close the message handle when there are no more messages to retrieve */
OCIMessageClose(hndl, errhp, msghnd);

See Also:
•

Oracle Database Data Cartridge Developer's Guide

•

OCI Messaging Functions

4.6.12 lmsgen Utility
The lmsgen utility converts text-based message files (.msg) into binary format (.msb) so
that Oracle Database messages and OCI messages provided by the user can be
returned to OCI functions in the desired language.
The BNF syntax of the Imsgen utility is as follows:
lmsgen text_file product facility [language]

In the preceding syntax:
•

text_file is a message text file.

•

product is the name of the product.

•

facility is the name of the facility.

•

language is the optional message language corresponding to the language
specified in the NLS_LANG parameter. The language parameter is required if the

message file is not tagged properly with language.
This section includes the following topics:
•

Guidelines for Text Message Files

•

An Example of Creating a Binary Message File from a Text Message File

4.6.12.1 Guidelines for Text Message Files
What are the guidelines that text message files must follow.
Text message files must follow these guidelines:

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OCI Globalization Support

•

Lines that start with "/" and "//" are treated as internal comments and are ignored.

•

To tag the message file with a specific language, include a line similar to the
following:
#

•

CHARACTER_SET_NAME= Japanese_Japan.JA16EUC

Each message contains three fields:
message_number, warning_level, message_text

–

The message number must be unique within a message file.

–

The warning level is not currently used. Set to 0.

–

The message text cannot be longer than 76 bytes.

The following is an example of an Oracle Database message text file:
/ Copyright (c) 2001 by the Oracle Corporation. All rights reserved.
/ This is a test us7ascii message file
# CHARACTER_SET_NAME= american_america.us7ascii
/
00000, 00000, "Export terminated unsuccessfully\n"
00003, 00000, "no storage definition found for segment(%lu, %lu)"

4.6.12.2 An Example of Creating a Binary Message File from a Text Message
File
How do you create a binary message file from a text message file.
The following table contains sample values for the lmsgen parameters:
lmsgen Parameter

Value

product

$HOME/myApplication

facility

imp

language

AMERICAN

text_file

impus.msg

The text message file is found in the following location:
$HOME/myApp/mesg/impus.msg

One of the lines in the text message file is:
00128,2, "Duplicate entry %s found in %s"

The lmsgen utility converts the text message file (impus.msg) into binary format, resulting
in a file called impus.msb:
% lmsgen impus.msg $HOME/myApplication imp AMERICAN

The following output results:
Generating message file impus.msg -->
/home/scott/myApplication/mesg/impus.msb
NLS Binary Message File Generation Utility: Version 9.2.0.0.0 -Production

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Copyright (c) Oracle Corporation 1979, 2001. All rights reserved.
CORE

9.2.0.0.0

Production

4-49

5
Data Types
This chapter provides a reference to Oracle external data types used by OCI
applications.
It also discusses Oracle data types and the conversions between internal and external
representations that occur when you transfer data between your program and an
Oracle database.
This chapter contains these topics:
•

Oracle Data Types

•

Internal Data Types

•

External Data Types

•

Data Conversions

•

Typecodes

•

Definitions in oratypes.h

See Also:
Oracle Database SQL Language Reference for detailed information
about Oracle internal data types

5.1 Oracle Data Types
One of the main functions of an OCI program is to communicate with an Oracle
database.
The OCI application may retrieve data from database tables through SQL SELECT
queries, or it may modify existing data in tables through INSERT, UPDATE, or DELETE
statements.
Inside a database, values are stored in columns in tables. Internally, Oracle represents
data in particular formats known as internal data types. Examples of internal data
types include NUMBER, CHAR, and DATE (see Table 5-1).
In general, OCI applications do not work with internal data type representations of
data, but with host language data types that are predefined by the language in which
they are written. When data is transferred between an OCI client application and a
database table, the OCI libraries convert the data between internal data types and
external data types.
External data types are host language types that have been defined in the OCI header
files. When an OCI application binds input variables, one of the bind parameters is an
indication of the external data type code (or SQLT code) of the variable. Similarly,

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Oracle Data Types

when output variables are specified in a define call, the external representation of the
retrieved data must be specified.
In some cases, external data types are similar to internal types. External types provide
a convenience for the programmer by making it possible to work with host language
types instead of proprietary data formats.

Note:
Even though some external types are similar to internal types, an OCI
application never binds to internal data types. They are discussed here
because it can be useful to understand how internal types can map to
external types.

OCI can perform a wide range of data type conversions when transferring data
between an Oracle database and an OCI application. There are more OCI external
data types than Oracle internal data types. In some cases, a single external type maps
to an internal type; in other cases, multiple external types map to a single internal type.
The many-to-one mappings for some data types provide flexibility for the OCI
programmer. For example, suppose that you are processing the following SQL
statement:
SELECT sal FROM emp WHERE empno = :employee_number

You want the salary to be returned as character data, instead of a binary floating-point
format. Therefore, you specify an Oracle database external string data type, such as
VARCHAR2 (code = 1) or CHAR (code = 96) for the dty parameter in the OCIDefineByPos()
or OCIDefineByPos2() call for the sal column. You also must declare a string variable in
your program and specify its address in the valuep parameter. See Table 5-2 for more
information.
If you want the salary information to be returned as a binary floating-point value,
however, specify the FLOAT (code = 4) external data type. You also must define a
variable of the appropriate type for the valuep parameter.
Oracle Database performs most data conversions transparently. The ability to specify
almost any external data type provides a lot of power for performing specialized tasks.
For example, you can input and output DATE values in pure binary format, with no
character conversion involved, by using the DATE external data type.
To control data conversion, you must use the appropriate external data type codes in
the bind and define routines. You must tell Oracle Database where the input or output
variables are in your OCI program and their data types and lengths.
OCI also supports an additional set of OCI typecodes that are used by the Oracle
Database type management system to represent data types of object type attributes.
You can use a set of predefined constants to represent these typecodes. The
constants each contain the prefix OCI_TYPECODE.
In summary, the OCI programmer must be aware of the following different data types
or data representations:

5-2

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Oracle Data Types

•

Internal Oracle data types, which are used by table columns in an Oracle
database. These also include data types used by PL/SQL that are not used by
Oracle Database columns (for example, indexed table, boolean, record).

•

External OCI data types, which are used to specify host language representations
of Oracle data.

•

OCI_TYPECODE values, which are used by Oracle Database to represent type

information for object type attributes.
Information about a column's internal data type is conveyed to your application in the
form of an internal data type code. With this information about what type of data is to
be returned, your application can determine how to convert and format the output data.
The Oracle internal data type codes are listed in the section Internal Data Types.

See Also:
•

DATE for a description of the external data type

•

Internal Data Types

•

External Data Types and About Using External Data Type Codes

•

Typecodes, and Relationship Between SQLT and OCI_TYPECODE
Values

•

Oracle Database SQL Language Reference for detailed information
about Oracle internal data types

•

About Describing Select-List Items for information about describing
select-list items in a query

5.1.1 About Using External Data Type Codes
An external data type code indicates to Oracle Database how a host variable
represents data in your program.
This determines how the data is converted when it is returned to output variables in
your program, or how it is converted from input (bind) variables to Oracle Database
column values. For example, to convert a NUMBER in an Oracle database column to a
variable-length character array, you specify the VARCHAR2 external data type code in the
OCIDefineByPos() call that defines the output variable.
To convert a bind variable to a value in an Oracle Database column, specify the
external data type code that corresponds to the type of the bind variable. For example,
to input a character string such as 02-FEB-65 to a DATE column, specify the data type
as a character string and set the length parameter to 9.
It is always the programmer's responsibility to ensure that values are convertible. If
you try to insert the string "MY BIRTHDAY" into a DATE column, you get an error when
you execute the statement.

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Chapter 5

Internal Data Types

See Also:
Table 5-2 for a complete list of the external data types and data type codes

5.2 Internal Data Types
Lists and describes the internal data types.
Table 5-1 lists the internal Oracle Database data types (also known as built-in), along
with each type's maximum internal length and data type code. PL/SQL types listed in
Table 5-10 and Table 5-11 are also considered to be internal data types.
Table 5-1

Internal Oracle Database Data Types

Internal Oracle Database Data Type

Maximum Internal Length

Data Type
Code

VARCHAR2, NVARCHAR2

4000 bytes (standard)

1

32767 bytes (extended)
NUMBER

21 bytes

2

LONG

2^31-1 bytes (2 gigabytes)

8

DATE

7 bytes

12

RAW

2000 bytes (standard)

23

32767 bytes (extended)
LONG RAW

2^31-1 bytes

24

ROWID

10 bytes

69

CHAR, NCHAR

2000 bytes

96

BINARY_FLOAT

4 bytes

100

BINARY_DOUBLE

8 bytes

101

User-defined type (object type, VARRAY, nested Not Applicable
table)

108

REF

Not Applicable

111

CLOB, NCLOB

128 terabytes

112

BLOB

128 terabytes

113

BFILE

Maximum operating system
file size or UB8MAXVAL

114

TIMESTAMP

11 bytes

180

TIMESTAMP WITH TIME ZONE

13 bytes

181

INTERVAL YEAR TO MONTH

5 bytes

182

INTERVAL DAY TO SECOND

11 bytes

183

UROWID

3950 bytes

208

TIMESTAMP WITH LOCAL TIME ZONE

11 bytes

231

This section includes the following topics:
•

LONG, RAW, LONG RAW, VARCHAR2

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Chapter 5

Internal Data Types

•

Character Strings and Byte Arrays

•

UROWID

•

BINARY_FLOAT and BINARY_DOUBLE

See Also:
Oracle Database SQL Language Reference for more information about these
built-in data types

5.2.1 LONG, RAW, LONG RAW, VARCHAR2
Use piecewise capabilities provided by specific OCI APIs to perform inserts, updates
or fetches of these data types.
You can use the piecewise capabilities provided by OCIBindByName() or
OCIBindByName2(), OCIBindByPos() or OCIBindByPos2(), OCIDefineByPos() or
OCIDefineByPos2(), OCIStmtGetPieceInfo(), and OCIStmtSetPieceInfo() to perform
inserts, updates or fetches involving column data of the LONG, RAW, LONG RAW, and
VARCHAR2 data types.

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIStmtGetPieceInfo()

•

OCIStmtSetPieceInfo()

5.2.2 Character Strings and Byte Arrays
Use Oracle internal data types to specify columns that contain characters or arrays of
bytes.
You can use following Oracle internal data types to specify columns that contain
characters or arrays of bytes: CHAR, VARCHAR2, RAW, LONG, and LONG RAW.

Note:
LOBs can contain characters and BFILEs can contain binary data. They are
handled differently than other types, so they are not included in this
discussion.

5-5

Chapter 5

Internal Data Types

CHAR, VARCHAR2, and LONG columns normally hold character data. RAW and LONG RAW hold
bytes that are not interpreted as characters (for example, pixel values in a bit-mapped
graphic image). Character data can be transformed when it is passed through a
gateway between networks. Character data passed between machines using different
languages, where single characters may be represented by differing numbers of bytes,
can be significantly changed in length. Raw data is never converted in this way.

It is the responsibility of the database designer to choose the appropriate Oracle
internal data type for each column in the table. The OCI programmer must be aware of
the many possible ways that character and byte-array data can be represented and
converted between variables in the OCI program and Oracle Database tables.
When an array holds characters, the length parameter for the array in an OCI call is
always passed in and returned in bytes, not characters.

See Also:
LOB and BFILE Operations for more information about CHAR, VARCHAR2, RAW,
LONG, and LONG RAW data types

5.2.3 UROWID
The Universal ROWID (UROWID) is a data type that can store both logical and physical
rowids of Oracle Database tables.
Logical rowids are primary key-based logical identifiers for the rows of index-organized
tables (IOTs).
To use columns of the UROWID data type, the value of the COMPATIBLE initialization
parameter must be set to 8.1 or later.
The following host variables can be bound to Universal ROWIDs:
•

SQLT_CHR (VARCHAR2)

•

SQLT_VCS (VARCHAR)

•

SQLT_STR (NULL-terminated string)

•

SQLT_LVC (LONG VARCHAR)

•

SQLT_AFC (CHAR)

•

SQLT_AVC (CHARZ)

•

SQLT_VST (OCI String)

•

SQLT_RDD (ROWID descriptor)

5.2.4 BINARY_FLOAT and BINARY_DOUBLE
The BINARY_FLOAT and BINARY_DOUBLE data types represent single-precision and doubleprecision floating point values that mostly conform to the IEEE754 Standard for
Floating-Point Arithmetic.
Prior to the addition of these data types with release 10.1, all numeric values in an
Oracle Database were stored in the Oracle NUMBER format. These new binary floating

5-6

Chapter 5

External Data Types

point types do not replace Oracle NUMBER. Rather, they are alternatives to Oracle NUMBER
that provide the advantage of using less disk storage.
These internal types are represented by the following codes:
•

SQLT_IBFLOAT for BINARY_FLOAT

•

SQLT_IBDOUBLE for BINARY_DOUBLE

All the following host variables can be bound to BINARY_FLOAT and BINARY_DOUBLE data
types:
•

SQLT_BFLOAT (native float)

•

SQLT_BDOUBLE (native double)

•

SQLT_INT (integer)

•

SQLT_FLT (float)

•

SQLT_NUM (Oracle NUMBER)

•

SQLT_UIN (unsigned)

•

SQLT_VNU (VARNUM)

•

SQLT_CHR (VARCHAR2)

•

SQLT_VCS (VARCHAR)

•

SQLT_STR (NULL-terminated String)

•

SQLT_LVC (LONG VARCHAR)

•

SQLT_AFC (CHAR)

•

SQLT_AVC (CHARZ)

•

SQLT_VST (OCIString)

For best performance, use external types SQLT_BFLOAT and SQLT_BDOUBLE in conjunction
with the BINARY_FLOAT and BINARY_DOUBLE data types.

5.3 External Data Types
Lists and describes the data type codes for external data types.
Table 5-2 lists data type codes for external data types. For each data type, the table
lists the program variable types for C from or to which Oracle Database internal data is
normally converted.
Table 5-2

External Data Types and Codes

External Data Type

Code

Program Variable1

OCI-Defined Constant

VARCHAR2

1

char[n]

SQLT_CHR

NUMBER

2

unsigned char[21]

SQLT_NUM

8-bit signed INTEGER

3

signed char

SQLT_INT

16-bit signed INTEGER

3

signed short, signed int

SQLT_INT

32-bit signed INTEGER

3

signed int, signed long

SQLT_INT

64-bit signed INTEGER

3

signed long, signed long long

SQLT_INT

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Chapter 5

External Data Types

Table 5-2

(Cont.) External Data Types and Codes

External Data Type

Code

Program Variable1

OCI-Defined Constant

FLOAT

4

float, double

SQLT_FLT

NULL-terminated STRING

5

char[n+1]

SQLT_STR

VARNUM

6

char[22]

SQLT_VNU

LONG

8

char[n]

SQLT_LNG

VARCHAR

9

char[n+sizeof(short integer)]

SQLT_VCS

DATE

12

char[7]

SQLT_DAT

VARRAW

15

unsigned char[n+sizeof(short
integer)]

SQLT_VBI

native float

21

float

SQLT_BFLOAT

native double

22

double

SQLT_BDOUBLE

RAW

23

unsigned char[n]

SQLT_BIN

LONG RAW

24

unsigned char[n]

SQLT_LBI

UNSIGNED INT

68

unsigned

SQLT_UIN

LONG VARCHAR

94

char[n+sizeof(integer)]

SQLT_LVC

LONG VARRAW

95

unsigned char[n+sizeof(integer)] SQLT_LVB

CHAR

96

char[n]

SQLT_AFC

CHARZ

97

char[n+1]

SQLT_AVC

ROWID descriptor

104

OCIRowid *

SQLT_RDD

NAMED DATATYPE

108

struct

SQLT_NTY

REF

110

OCIRef

SQLT_REF

112

OCILobLocator2

SQLT_CLOB

Binary LOB descriptor

113

OCILobLocator2

SQLT_BLOB

Binary FILE descriptor

114

OCILobLocator

SQLT_FILE

OCI STRING type

155

OCIString

SQLT_VST3

OCI DATE type

156

OCIDate *

SQLT_ODT3

ANSI DATE descriptor

184

OCIDateTime *

SQLT_DATE

TIMESTAMP descriptor

187

OCIDateTime *

SQLT_TIMESTAMP

TIMESTAMP WITH TIME ZONE
descriptor

188

OCIDateTime *

SQLT_TIMESTAMP_TZ

INTERVAL YEAR TO MONTH descriptor 189

OCIInterval *

SQLT_INTERVAL_YM

INTERVAL DAY TO SECOND descriptor 190

OCIInterval *

SQLT_INTERVAL_DS

OCIDateTime *

SQLT_TIMESTAMP_LTZ

Character LOB descriptor

TIMESTAMP WITH LOCAL TIME ZONE
descriptor
1
2
3

232

Where the length is shown as n, it is a variable, and depends on the requirements of the program (or of the operating system
for ROWID).
In applications using data type mappings generated by OTT, CLOBs may be mapped as OCIClobLocator, and BLOBs may be
mapped as OCIBlobLocator. For more information, see Chapter 15.
For more information about the use of these data types, see Chapter 12.

This section includes the following topics describing these external data types:

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Chapter 5

External Data Types

•

VARCHAR2

•

NUMBER

•

64-Bit Integer Host Data Type

•

INTEGER

•

FLOAT

•

STRING

•

VARNUM

•

LONG

•

VARCHAR

•

DATE

•

RAW

•

VARRAW

•

LONG RAW

•

UNSIGNED

•

LONG VARCHAR

•

LONG VARRAW

•

CHAR

•

CHARZ

•

Named Data Types: Object, VARRAY, Nested Table

•

REF

•

ROWID Descriptor

•

LOB Descriptor

•

Datetime and Interval Data Type Descriptors

•

Native Float and Native Double

•

C Object-Relational Data Type Mappings

5.3.1 VARCHAR2
The VARCHAR2 data type is a variable-length string of characters with a maximum length
of 4000 bytes.
If the init.ora parameter max_string_size = standard (default value), the maximum
length of a VARCHAR2 can be 4000 bytes. If the init.ora parameter max_string_size =
extended, the maximum length of a VARCHAR2 can be 32767 bytes.

Note:
If you are using Oracle Database objects, you can work with a special
OCIString external data type using a set of predefined OCI functions.

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Chapter 5

External Data Types

This section includes the following topics:
•

Input

•

Output

See Also:
•

init.ora parameter MAX_STRING_SIZE in Oracle Database Reference
for more information about extended data types

•

Object-Relational Data Types in OCI for more information about the
OCIString external data type

5.3.1.1 Input
The value_sz parameter determines the length in the OCIBindByName() or OCIBindByPos()
call. If you are using extended VARCHAR2 lengths, then the value_sz parameter
determines the length in the OCIBindByName2() and OCIBindByPos2() calls.
If the value_sz parameter is greater than zero, Oracle Database obtains the bind
variable value by reading exactly that many bytes, starting at the buffer address in
your program. Trailing blanks are stripped, and the resulting value is used in the SQL
statement or PL/SQL block. If, with an INSERT statement, the resulting value is longer
than the defined length of the database column, the INSERT fails, and an error is
returned.

Note:
A trailing NULL is not stripped. Variables should be blank-padded but not NULLterminated.

If the value_sz parameter is zero, Oracle Database treats the bind variable as a NULL,
regardless of its actual content. Of course, a NULL must be allowed for the bind variable
value in the SQL statement. If you try to insert a NULL into a column that has a NOT NULL
integrity constraint, Oracle Database issues an error, and the row is not inserted.
When the Oracle internal (column) data type is NUMBER, input from a character string
that contains the character representation of a number is legal. Input character strings
are converted to internal numeric format. If the VARCHAR2 string contains an illegal
conversion character, Oracle Database returns an error and the value is not inserted
into the database.

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See Also:
•

OCIBindByName()

•

OCIBindByPos()

•

OCIBindByName2()

•

OCIBindByPos2()

5.3.1.2 Output
You must specify the desired length for the return value in value_sz for bind and define
functions.
Specify the desired length for the return value in the value_sz parameter of the
OCIDefineByPos() call, or the value_sz parameter of OCIBindByName() or OCIBindByPos()
for PL/SQL blocks. If zero is specified for the length, no data is returned. If you are
using extended VARCHAR2 lengths, then the value_sz parameter determines the desired
length for the return value in the OCIDefineByPos2() call, or in the OCIBindByName2() and
OCIBindByPos2() calls for PL/SQL blocks.
If you omit the rlenp parameter of OCIDefineByPos(), returned values are blank-padded
to the buffer length, and NULLs are returned as a string of blank characters. If rlenp is
included, returned values are not blank-padded. Instead, their actual lengths are
returned in the rlenp parameter.
To check if a NULL is returned or if character truncation has occurred, include an
indicator parameter in the OCIDefineByPos() call. Oracle Database sets the indicator
parameter to -1 when a NULL is fetched and to the original column length when the
returned value is truncated. Otherwise, it is set to zero. If you do not specify an
indicator parameter and a NULL is selected, the fetch call returns the error code
OCI_SUCCESS_WITH_INFO. Retrieving diagnostic information for the error returns ORA-1405.

See Also:
•

Indicator Variables

•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

5.3.2 NUMBER
You should not need to use NUMBER as an external data type.
If you do use it as an external data type, Oracle Database returns numeric values in its
internal 21-byte binary format and expects this format on input. The following
discussion is included for completeness only.

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Note:
If you are using objects in an Oracle database, you can work with a special
OCINumber data type using a set of predefined OCI functions.

Oracle Database stores values of the NUMBER data type in a variable-length format. The
first byte is the exponent and is followed by 1 to 20 mantissa bytes. The high-order bit
of the exponent byte is the sign bit; it is set for positive numbers, and it is cleared for
negative numbers. The lower 7 bits represent the exponent, which is a base-100 digit
with an offset of 65.
To calculate the decimal exponent, add 65 to the base-100 exponent and add another
128 if the number is positive. If the number is negative, you do the same, but
subsequently the bits are inverted. For example, -5 has a base-100 exponent = 62
(0x3e). The decimal exponent is thus (~0x3e) -128 - 65 = 0xc1 -128 -65 = 193 -128
-65 = 0.
Each mantissa byte is a base-100 digit, in the range 1..100. For positive numbers, the
digit has 1 added to it. So, the mantissa digit for the value 5 is 6. For negative
numbers, instead of adding 1, the digit is subtracted from 101. So, the mantissa digit
for the number -5 is 96 (101 - 5). Negative numbers have a byte containing 102
appended to the data bytes. However, negative numbers that have 20 mantissa bytes
do not have the trailing 102 byte. Because the mantissa digits are stored in base 100,
each byte can represent 2 decimal digits. The mantissa is normalized; leading zeros
are not stored.
Up to 20 data bytes can represent the mantissa. However, only 19 are guaranteed to
be accurate. The 19 data bytes, each representing a base-100 digit, yield a maximum
precision of 38 digits for an Oracle NUMBER.
If you specify the data type code 2 in the dty parameter of an OCIDefineByPos() or
OCIDefineByPos2() call, your program receives numeric data in this Oracle internal
format. The output variable should be a 21-byte array to accommodate the largest
possible number. Note that only the bytes that represent the number are returned.
There is no blank padding or NULL termination. If you must know the number of bytes
returned, use the VARNUM external data type instead of NUMBER.

See Also:
•

OCINumber Examples

•

VARNUM for a description of the internal NUMBER format

•

Number (OCINumber) more information about the OCINumber data type

•

OCIDefineByPos() or OCIDefineByPos2()

5.3.3 64-Bit Integer Host Data Type
You can bind and define integer values greater than 32-bit size (more than nine digits
of precision) from and into a NUMBER column using a 64-bit native host variable and
SQLT_INT or SQLT_UIN as the external data type in an OCI application.

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Starting with release 11.2, OCI supports the ability to bind and define integer values
greater than 32-bit size (more than nine digits of precision) from and into a NUMBER
column using a 64-bit native host variable and SQLT_INT or SQLT_UIN as the external
data type in an OCI application.
This feature enables an application to bind and define 8-byte native host variables
using SQLT_INT or SQLT_UIN external data types in the OCI bind and define function calls
on all platforms. The OCIDefineByPos() or OCIDefineByPos2(), OCIBindByName() or
OCIBindByName2(), and OCIBindByPos() or OCIBindByPos2() function calls can specify an
8-byte integer data type pointer as the valuep parameter. This feature enables you to
insert and fetch large integer values (up to 18 decimal digits of precision) directly into
and from native host variables and to perform free arithmetic on them.
This section includes the following topics:
•

OCI Bind and Define for 64-Bit Integers

•

Support for OUT Bind DML Returning Statements

•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

5.3.3.1 OCI Bind and Define for 64-Bit Integers
Shows a code fragment for an OCI bind and define for 64-bit integers.
Example 5-1 shows a code fragment that works without errors.
Example 5-1

OCI Bind and Define Support for 64-Bit Integers

...
/* Variable declarations */
orasb8
sbigval1, sbigval2, sbigval3; // Signed 8-byte variables.
oraub8
ubigval1, ubigval2, ubigval3; // Unsigned 8-byte variables.
...
/* Bind Statements */
OCIBindByPos(..., (void *) &sbigval1, sizeof(sbigval1), ..., SQLT_INT, ...);
OCIBindByPos(..., (void *) &ubigval1, sizeof(ubigval1), ..., SQLT_UIN, ...);
OCIBindByName(...,(void *) &sbigval2, sizeof(sbigval2), ..., SQLT_INT, ...);
OCIBindByName(...,(void *) &ubigval2, sizeof(ubigval2), ..., SQLT_UIN, ...);
...
/* Define Statements */
OCIDefineByPos(..., (void *) &sbigval3, sizeof(sbigval3), ..., SQLT_INT, ...);
OCIDefineByPos(..., (void *) &ubigval3, sizeof(ubigval3), ..., SQLT_UIN, ...);
...

5.3.3.2 Support for OUT Bind DML Returning Statements
Shows a code fragment that illustrates binding 8-byte integer data types for OUT binds
of a DML returning statement.
Example 5-2 shows a code fragment that illustrates binding 8-byte integer data types
for OUT binds of a DML returning statement.

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Example 5-2 Binding 8-Byte Integer Data Types for OUT Binds of a DML
Returning Statement
...
/* Define SQL statements to be used in program. */
static text *dml_stmt = (text *) " UPDATE emp SET sal = sal + :1
WHERE empno = :2
RETURNING sal INTO :out1";
...
/* Declare
OCIStmt
OCIError
OCIBind
OCIBind
OCIBind
...

all handles to be used
*stmthp;
*errhp;
*bnd1p = (OCIBind *)
*bnd2p = (OCIBind *)
*bnd3p = (OCIBind *)

in program. */

0;
0;
0;

/* Bind variable declarations */
orasb8
sbigval; // OUT bind variable (8-byte size).
sword
eno, hike; // IN bind variables.
...
/* get values for IN bind variables */
...
/* Bind Statements */
OCIBindByPos(stmthp, &bnd1p, errhp, 1, (dvoid *) &hike,
(sb4) sizeof(hike), SQLT_INT, (dvoid *) 0,
(ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT);
OCIBindByPos(stmthp, &bnd2p, errhp, 2, (dvoid *) &eno,
(sb4) sizeof(eno), SQLT_INT, (dvoid *) 0,
(ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT);
OCIBindByName(stmthp, &bnd3p, errhp, (text *) ":out1", -1,
(dvoid *) &sbigval, sizeof(sbigval), SQLT_INT, (dvoid *) 0,
(ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT);
...
/* Use the returned OUT bind variable value */
...

5.3.4 INTEGER
The INTEGER data type converts numbers.
An external integer is a signed binary number; the size in bytes is system-dependent.
The host system architecture determines the order of the bytes in the variable. A
length specification is required for input and output. If the number being returned from
Oracle Database is not an integer, the fractional part is discarded, and no error or
other indication is returned. If the number to be returned exceeds the capacity of a
signed integer for the system, Oracle Database returns an "overflow on conversion"
error.

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5.3.5 FLOAT
The FLOAT data type processes numbers that have fractional parts or that exceed the
capacity of an integer.
The number is represented in the host system's floating-point format. Normally the
length is either 4 or 8 bytes. The length specification is required for both input and
output.
The internal format of an Oracle number is decimal, and most floating-point
implementations are binary; therefore, Oracle Database can represent numbers with
greater precision than floating-point representations.

Note:
You may receive a round-off error when converting between FLOAT and
NUMBER. Using a FLOAT as a bind variable in a query may return an ORA-1403
error. You can avoid this situation by converting the FLOAT into a STRING and
then using VARCHAR2 or a NULL-terminated string for the operation.

5.3.6 STRING
The NULL-terminated STRING format behaves like the VARCHAR2 format, except that the
string must contain a NULL terminator character.
The STRING data type is most useful for C language programs.
This section includes the following topics:
•

Input

•

Output

5.3.6.1 Input
The string length supplied in the OCIBindByName() or OCIBindByPos() call limits the scan
for the NULL terminator.
If the NULL terminator is not found within the length specified, Oracle Database issues
the following error:
ORA-01480: trailing NULL missing from STR bind value
If the length is not specified in the bind call, OCI uses an implied maximum string
length of 4000.
The minimum string length is 2 bytes. If the first character is a NULL terminator and the
length is specified as 2, a NULL is inserted into the column, if permitted. Unlike types
VARCHAR2 and CHAR, a string containing all blanks is not treated as a NULL on input; it is
inserted as is.

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Note:
You cannot pass -1 for the string length parameter of a NULL-terminated
string

5.3.6.2 Output
A NULL terminator is placed after the last character returned.
If the string exceeds the field length specified, it is truncated and the last character
position of the output variable contains the NULL terminator.
A NULL select-list item returns a NULL terminator character in the first character position.
An ORA-01405 error is also possible.

5.3.7 VARNUM
The VARNUM data type is like the external NUMBER data type, except that the first byte
contains the length of the number representation.
This length does not include the length byte itself. Reserve 22 bytes to receive the
longest possible VARNUM. Set the length byte when you send a VARNUM value to Oracle
Database.
Table 5-3 shows several examples of the VARNUM values returned for numbers in a
table.
Table 5-3

VARNUM Examples

Decimal Value

Length Byte

Exponent Byte Mantissa Bytes

Terminator Byte

0

1

128

Not applicable

Not applicable

5

2

193

6

Not applicable

-5

3

62

96

102

2767

3

194

28, 68

Not applicable

-2767

4

61

74, 34

102

100000

2

195

11

Not applicable

1234567

5

196

2, 24, 46, 68

Not applicable

5.3.8 LONG
The LONG data type stores character strings longer than 4000 bytes.
You can store up to 2 gigabytes (2^31-1 bytes) in a LONG column. Columns of this type
are used only for storage and retrieval of long strings. They cannot be used in
functions, expressions, or WHERE clauses. LONG column values are generally converted
to and from character strings.
Do not create tables with LONG columns. Use LOB columns (CLOB, NCLOB, or BLOB) instead.
LONG columns are supported only for backward compatibility.

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Oracle also recommends that you convert existing LONG columns to LOB columns. LOB
columns are subject to far fewer restrictions than LONG columns. Furthermore, LOB
functionality is enhanced in every release, but LONG functionality has been static for
several releases.

5.3.9 VARCHAR
The VARCHAR data type stores character strings of varying length.
The first 2 bytes contain the length of the character string, and the remaining bytes
contain the string. The specified length of the string in a bind or a define call must
include the two length bytes, so the largest VARCHAR string that can be received or sent
is 65533 bytes long, not 65535.

5.3.10 DATE
The DATE data type can update, insert, or retrieve a date value using the Oracle internal
date binary format.
A date in binary format contains 7 bytes, as shown in Table 5-4.
Table 5-4

Format of the DATE Data Type

Byte

1

2

3

4

5

6

7

Meaning

Century

Year

Month

Day

Hour

Minute

Second

Example (for 30NOV-1992, 3:17 PM)

119

192

11

30

16

18

1

The century and year bytes (bytes 1 and 2) are in excess-100 notation. The first byte
stores the value of the year, which is 1992, as an integer, divided by 100, giving 119 in
excess-100 notation. The second byte stores year modulo 100, giving 192. Dates
Before Common Era (BCE) are less than 100. The era begins on 01-JAN-4712 BCE,
which is Julian day 1. For this date, the century byte is 53, and the year byte is 88. The
hour, minute, and second bytes are in excess-1 notation. The hour byte ranges from 1
to 24, the minute and second bytes from 1 to 60. If no time was specified when the
date was created, the time defaults to midnight (1, 1, 1).
When you enter a date in binary format using the DATE external data type, the database
does not do consistency or range checking. All data in this format must be carefully
validated before input.

Note:
There is little need to use the Oracle external DATE data type in ordinary
database operations. It is much more convenient to convert DATE into
character format, because the program usually deals with data in a character
format, such as DD-MON-YY.

When a DATE column is converted to a character string in your program, it is returned
using the default format mask for your session, or as specified in the INIT.ORA file.

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If you are using objects in an Oracle database, you can work with a special OCIDate
data type using a set of predefined OCI functions.

See Also:
•

Date (OCIDate) for more information about the OCIDate data type

•

Datetime and Interval Data Type Descriptors for information about
DATETIME and INTERVAL data types

5.3.11 RAW
The RAW data type is used for binary data or byte strings that are not to be interpreted
by Oracle Database, for example, to store graphics character sequences.
The maximum length of a RAW column is 2000 bytes. If the init.ora parameter
max_string_size = standard (default value), the maximum length of a RAW can be 2000
bytes. If the init.ora parameter max_string_size = extended, the maximum length of a
RAW can be 32767 bytes.
When RAW data in an Oracle Database table is converted to a character string in a
program, the data is represented in hexadecimal character code. Each byte of the RAW
data is returned as two characters that indicate the value of the byte, from '00' to 'FF'.
To input a character string in your program to a RAW column in an Oracle Database
table, you must code the data in the character string using this hexadecimal code.
You can use the piecewise capabilities provided by OCIDefineByPos(), OCIBindByName(),
OCIBindByPos(), OCIStmtGetPieceInfo(), and OCIStmtSetPieceInfo() to perform inserts,
updates, or fetches involving RAW (or LONG RAW) columns.
If you are using objects in an Oracle database, you can work with a special OCIRaw data
type using a set of predefined OCI functions.

See Also:
•

Oracle Database SQL Language Reference for more information about
MAX_STRING_SIZE

•

init.ora parameter MAX_STRING_SIZE in Oracle Database Reference

for more information about extended data types
•

Raw (OCIRaw)for more information about this data type

5.3.12 VARRAW
The VARRAW data type is similar to the RAW data type.
However, the first 2 bytes contain the length of the data. The specified length of the
string in a bind or a define call must include the two length bytes, so the largest VARRAW
string that can be received or sent is 65533 bytes, not 65535. For converting longer
strings, use the LONG VARRAW external data type.

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5.3.13 LONG RAW
The LONG RAW data type supports a 2 gigabyte length.
The LONG RAW data type is similar to the RAW data type, except that it stores raw data with
a length up to 2 gigabytes (2^31-1 bytes).

5.3.14 UNSIGNED
The UNSIGNED data type is used for unsigned binary integers.
The size in bytes is system-dependent. The host system architecture determines the
order of the bytes in a word. A length specification is required for input and output. If
the number being output from Oracle Database is not an integer, the fractional part is
discarded, and no error or other indication is returned. If the number to be returned
exceeds the capacity of an unsigned integer for the system, Oracle Database returns
an "overflow on conversion" error.

5.3.15 LONG VARCHAR
The LONG VARCHAR data type stores data from and into an Oracle Database LONG column.
The first 4 bytes of a LONG VARCHAR contain the length of the item. So, the maximum
length of a stored item is 2^31-5 bytes.

5.3.16 LONG VARRAW
The LONG VARRAW data type is used to store data from and into an Oracle Database LONG
RAW column.
The length is contained in the first four bytes. The maximum length is 2^31-5 bytes.

5.3.17 CHAR
The CHAR data type is a string of characters, with a maximum length of 2000.
CHAR strings are compared using blank-padded comparison semantics.

This section includes the following topics:
•

Input

•

Output

See Also:
Oracle Database SQL Language Reference

5.3.17.1 Input
The length is determined by the value_sz parameter in the OCIBindByName() or
OCIBindByName2() or OCIBindByPos() or OCIBindByPos2()call.

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Note:
The entire contents of the buffer (value_sz chars) is passed to the database,
including any trailing blanks or NULLs.

If the value_sz parameter is zero, Oracle Database treats the bind variable as a NULL,
regardless of its actual content. Of course, a NULL must be allowed for the bind variable
value in the SQL statement. If you try to insert a NULL into a column that has a NOT NULL
integrity constraint, Oracle Database issues an error and does not insert the row.
Negative values for the value_sz parameter are not allowed for CHARs.
When the Oracle internal (column) data type is NUMBER, input from a character string
that contains the character representation of a number is legal. Input character strings
are converted to internal numeric format. If the CHAR string contains an illegal
conversion character, Oracle Database returns an error and does not insert the value.
Number conversion follows the conventions established by globalization support
settings for your system. For example, your system might be configured to recognize a
comma (,) rather than a period (.) as the decimal point.

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

5.3.17.2 Output
Specify the desired length for the return value in the value_sz parameter of the
OCIDefineByPos() or OCIDefineByPos2() call.

If zero is specified for the length, no data is returned.
If you omit the rlenp parameter of OCIDefineByPos() or OCIDefineByPos2(), returned
values are blank padded to the buffer length, and NULLs are returned as a string of
blank characters. If rlenp is included, returned values are not blank-padded. Instead,
their actual lengths are returned in the rlenp parameter.
To check whether a NULL is returned or character truncation occurs, include an
indicator parameter or array of indicator parameters in the OCIDefineByPos() or
OCIDefineByPos2() call. An indicator parameter is set to -1 when a NULL is fetched and
to the original column length when the returned value is truncated. Otherwise, it is set
to zero. If you do not specify an indicator parameter and a NULL is selected, the fetch
call returns an ORA-01405 error.
You can also request output to a character string from an internal NUMBER data type.
Number conversion follows the conventions established by the globalization support
settings for your system. For example, your system might use a comma (,) rather than
a period (.) as the decimal point.

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See Also:
•

Indicator Variables

•

OCIDefineByPos() or OCIDefineByPos2()

5.3.18 CHARZ
The CHARZ external data type is similar to the CHAR data type, except that the string must
be NULL-terminated on input, and Oracle Database places a NULL-terminator character
at the end of the string on output.
The NULL terminator serves only to delimit the string on input or output; it is not part of
the data in the table.
On input, the length parameter must indicate the exact length, including the NULL
terminator. For example, if an array in C is declared as follows, then the length
parameter when you bind my_num must be seven. Any other value would return an error
for this example.
char my_num[] = "123.45";

The following new external data types were introduced with or after release 8.0. These
data types are not supported when you connect to an Oracle release 7 server.

Note:
Both internal and external data types have Oracle-defined constant values,
such as SQLT_NTY, SQLT_REF, corresponding to their data type codes. Although
the constants are not listed for all of the types in this chapter, they are used
in this section when discussing new Oracle data types. The data type
constants are also used in other chapters of this guide when referring to
these new types.

5.3.19 Named Data Types: Object, VARRAY, Nested Table
Named data types are user-defined types that are specified with the CREATE TYPE
command in SQL.
Examples include object types, varrays, and nested tables. In OCI, named data type
refers to a host language representation of the type. The SQLT_NTY data type code is
used when binding or defining named data types.
In a C application, named data types are represented as C structs. These structs can
be generated from types stored in the database by using the Object Type Translator.
These types correspond to OCI_TYPECODE_OBJECT.

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See Also:
•

Object Type Information Storage and Access for more information about
working with named data types in OCI

•

Using the Object Type Translator with OCI for information about how
named data types are represented as C structs

5.3.20 REF
This is a reference to a named data type.
The C language representation of a REF is a variable declared to be of type OCIRef *.
The SQLT_REF data type code is used when binding or defining REFs.
Access to REFs is only possible when an OCI application has been initialized in object
mode. When REFs are retrieved from the server, they are stored in the client-side
object cache.
To allocate a REF for use in your application, you should declare a variable to be a
pointer to a REF, and then call OCIObjectNew(), passing OCI_TYPECODE_REF as the typecode
parameter.

See Also:
•
•

OCIObjectNew()
Object Advanced Topics in OCI for more information about working with
REFs in the OCI

5.3.21 ROWID Descriptor
The ROWID data type identifies a particular row in a database table.
ROWID can be a select-list item in a query, such as:
SELECT ROWID, ename, empno FROM emp

In this case, you can use the returned ROWID in further DELETE statements.
If you are performing a SELECT for UPDATE, the ROWID is implicitly returned. This ROWID can
be read into a user-allocated ROWID descriptor by using OCIAttrGet() on the statement
handle and used in a subsequent UPDATE statement. The prefetch operation fetches all
ROWIDs on a SELECT for UPDATE; use prefetching and then a single row fetch.
You access rowids using a ROWID descriptor, which you can use as a bind or define
variable.

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See Also:
•

OCIAttrGet()

•

OCI Descriptors and Positioned Updates and Deletes for more
information about the use of the ROWID descriptor

5.3.22 LOB Descriptor
A LOB (large object) stores binary or character data up to 128 terabytes (TB) in length.
Binary data is stored in a BLOB (binary LOB), and character data is stored in a CLOB
(character LOB) or NCLOB (national character LOB).
LOB values may or may not be stored inline with other row data in the database. In
either case, LOBs have the full transactional support of the Oracle database. A
database table stores a LOB locator that points to the LOB value, which may be in a
different storage space.
When an OCI application issues a SQL query that includes a LOB column or attribute
in its select list, fetching the results of the query returns the locator, rather than the
actual LOB value. In OCI, the LOB locator maps to a variable of type OCILobLocator.

Note:
Depending on your application, you may or may not want to use LOB
locators. You can use the data interface for LOBs, which does not require
LOB locators. In this interface, you can bind or define character data for CLOB
columns or RAW data for BLOB columns.

The OCI functions for LOBs take a LOB locator as one of their arguments. The OCI
functions assume that the locator has already been created, whether or not the LOB to
which it points contains data.
Bind and define operations are performed on the LOB locator, which is allocated with
the OCIDescriptorAlloc() function.
The locator is always fetched first using SQL or OCIObjectPin(), and then operations
are performed using the locator. The OCI functions never take the actual LOB value as
a parameter.
The data type codes available for binding or defining LOBs are:
•

SQLT_BLOB - A binary LOB data type

•

SQLT_CLOB - A character LOB data type

The NCLOB is a special type of CLOB with the following requirements:
•

To write into or read from an NCLOB, the user must set the character set form
(csfrm) parameter to be SQLCS_NCHAR.

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•

The amount (amtp) parameter in calls involving CLOBs and NCLOBs is always
interpreted in terms of characters, rather than bytes, for fixed-width character sets.

This section includes the following topics:
•

BFILE

•

BLOB

•

CLOB

•

NCLOB

See Also:
•

OCI Descriptors for more information about descriptors, including the
LOB locator

•

Oracle Database SQL Language Reference and Oracle Database
SecureFiles and Large Objects Developer's Guide for more information
about LOBs

•

About Binding LOB Data

•

About Defining LOB Data

•

LOB and BFILE Functions in OCI

•

OCIDescriptorAlloc()

•

OCIObjectPin()

•

LOB and BFILE Operations for more information about OCI LOB
functions

5.3.22.1 BFILE
Oracle Database supports access to binary files (BFILEs).
The BFILE data type provides access to LOBs that are stored in file systems outside an
Oracle database.
A BFILE column or attribute stores a file LOB locator, which serves as a pointer to a
binary file on the server's file system. The locator maintains the directory object and
the file name. The maximum size of a BFILE is the smaller of the operating system
maximum file size or UB8MAXVAL.
Binary file LOBs do not participate in transactions. Rather, the underlying operating
system provides file integrity and durability.
The database administrator must ensure that the file exists and that Oracle Database
processes have operating system read permissions on the file.
The BFILE data type allows read-only support of large binary files; you cannot modify a
file through Oracle Database. Oracle Database provides APIs to access file data.
The data type code available for binding or defining BFILEs is SQLT_BFILE (a binary FILE
LOB data type)

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External Data Types

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for more
information about directory aliases

5.3.22.2 BLOB
The BLOB data type stores unstructured binary large objects.
BLOBs can be thought of as bit streams with no character set semantics. BLOBs can

store up to 128 terabytes of binary data.
BLOBs have full transactional support; changes made through OCI participate fully in
the transaction. The BLOB value manipulations can be committed or rolled back. You
cannot save a BLOB locator in a variable in one transaction and then use it in another

transaction or session.

5.3.22.3 CLOB
The CLOB data type stores fixed-width or variable-width character data.
CLOBs can store up to 128 terabytes of character data.
CLOBs have full transactional support; changes made through OCI participate fully in
the transaction. The CLOB value manipulations can be committed or rolled back. You
cannot save a CLOB locator in a variable in one transaction and then use it in another
transaction or session.

5.3.22.4 NCLOB
An NCLOB is a national character version of a CLOB.
It stores fixed-width, single-byte or multibyte national character set (NCHAR) data, or
variable-width character set data. NCLOBs can store up to 128 terabytes of character
text data.
NCLOBs have full transactional support; changes made through OCI participate fully in
the transaction. NCLOB value manipulations can be committed or rolled back. You
cannot save an NCLOB locator in a variable in one transaction and then use it in another

transaction or session.

5.3.23 Datetime and Interval Data Type Descriptors
Lists and describes the datetime and interval data type descriptors.
The datetime and interval data type descriptors are briefly summarized here.
This section includes the following topics:
•

ANSI DATE

•

TIMESTAMP

•

TIMESTAMP WITH TIME ZONE

•

TIMESTAMP WITH LOCAL TIME ZONE

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External Data Types

•

INTERVAL YEAR TO MONTH

•

INTERVAL DAY TO SECOND

•

About Avoiding Unexpected Results Using Datetime

See Also:
Oracle Database SQL Language Reference

5.3.23.1 ANSI DATE
ANSI DATE is based on DATE, but contains no time portion. It also has no time zone.
ANSI DATE follows the ANSI specification for the DATE data type. When assigning an ANSI
DATE to a DATE or a time stamp data type, the time portion of the Oracle DATE and the
time stamp are set to zero. When assigning a DATE or a time stamp to an ANSI DATE, the

time portion is ignored.
Instead of using the ANSI DATE data type, Oracle recommends that you use the
TIMESTAMP data type, which contains both date and time.

5.3.23.2 TIMESTAMP
The TIMESTAMP data type is an extension of the DATE data type. It stores the year,
month, and day of the DATE data type, plus the hour, minute, and second values.
The TIMESTAMP data type has no time zone. The TIMESTAMP data type has the following
form:
TIMESTAMP(fractional_seconds_precision)

In this form, the optional fractional_seconds_precision specifies the number of digits in
the fractional part of the SECOND datetime field and can be a number in the range 0 to 9.
The default is 6.

5.3.23.3 TIMESTAMP WITH TIME ZONE
TIMESTAMP WITH TIME ZONE (TSTZ) is a variant of TIMESTAMP that includes an explicit time
zone displacement in its value.

The time zone displacement is the difference in hours and minutes between local time
and UTC (coordinated universal time—formerly Greenwich mean time). The TIMESTAMP
WITH TIME ZONE data type has the following form:
TIMESTAMP(fractional_seconds_precision) WITH TIME ZONE

In this form, fractional_seconds_precision optionally specifies the number of digits in
the fractional part of the SECOND datetime field, and can be a number in the range 0 to
9. The default is 6.
Two TIMESTAMP WITH TIME ZONE values are considered identical if they represent the
same instant in UTC, regardless of the TIME ZONE offsets stored in the data.

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External Data Types

5.3.23.4 TIMESTAMP WITH LOCAL TIME ZONE
TIMESTAMP WITH LOCAL TIME ZONE (TSLTZ) is another variant of TIMESTAMP that includes a
time zone displacement in its value.

Storage is in the same format as for TIMESTAMP. This type differs from TIMESTAMP WITH
TIME ZONE in that data stored in the database is normalized to the database time zone,
and the time zone displacement is not stored as part of the column data. When
retrieving the data, Oracle Database returns it in your local session time zone.
The time zone displacement is the difference (in hours and minutes) between local
time and UTC (coordinated universal time—formerly Greenwich mean time). The
TIMESTAMP WITH LOCAL TIME ZONE data type has the following form:
TIMESTAMP(fractional_seconds_precision) WITH LOCAL TIME ZONE

In this form, fractional_seconds_precision optionally specifies the number of digits in
the fractional part of the SECOND datetime field and can be a number in the range 0 to 9.
The default is 6.

5.3.23.5 INTERVAL YEAR TO MONTH
INTERVAL YEAR TO MONTH stores a period of time using the YEAR and MONTH datetime fields.

The INTERVAL YEAR TO MONTH data type has the following form:
INTERVAL YEAR(year_precision) TO MONTH

In this form, the optional year_precision is the number of digits in the YEAR datetime
field. The default value of year_precision is 2.

5.3.23.6 INTERVAL DAY TO SECOND
INTERVAL DAY TO SECOND stores a period of time in terms of days, hours, minutes, and

seconds.
The INTERVAL DAY TO SECOND data type has the following form:
INTERVAL DAY (day_precision) TO SECOND(fractional_seconds_precision)

In this form:
•

day_precision is the number of digits in the DAY datetime field. It is optional.

Accepted values are 0 to 9. The default is 2.
•

fractional_seconds_precision is the number of digits in the fractional part of the
SECOND datetime field. Accepted values are 0 to 9. The value should be provided as

nanoseconds. The Default Day to Second precision is 6 unless the precision is
specified to a different value at the time of creating the table. In this case, the least
significant three digits will be truncated.

5.3.23.7 About Avoiding Unexpected Results Using Datetime
How to avoid unexpected results using datetime.

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Note:
To avoid unexpected results in your data manipulation language (DML)
operations on datetime data, you can verify the database and session time
zones by querying the built-in SQL functions DBTIMEZONE and SESSIONTIMEZONE.
If the time zones have not been set manually, Oracle Database uses the
operating system time zone by default. If the operating system time zone is
not a valid Oracle Database time zone, Oracle Database uses UTC as the
default value.

5.3.24 Native Float and Native Double
The native float (SQLT_BFLOAT) and native double (SQLT_BDOUBLE) data types represent
the single-precision and double-precision floating-point values.
They are represented natively, that is, in the host system's floating-point format.
These external types were added in release 10.1 to externally represent the
BINARY_FLOAT and BINARY_DOUBLE internal data types. Thus, performance for the internal

types is best when used in conjunction with external types native float and native
double respectively. This draws a clear distinction between the existing representation
of floating-point values (SQLT_FLT) and these types.

5.3.25 C Object-Relational Data Type Mappings
OCI supports Oracle-defined C data types for mapping user-defined data types to C
representations (for example, OCINumber, OCIArray).
OCI provides a set of calls to operate on these data types, and to use these data types
in bind and define operations, in conjunction with OCI external data types.

See Also:
Object-Relational Data Types in OCI for information about using these
Oracle-defined C data types

5.4 Data Conversions
Shows the supported conversions from internal data types to external data types and
from external data types into internal column representations.
Table 5-5 shows the supported conversions from internal data types to external data
types, and from external data types into internal column representations, for all data
types available through release 7.3. Information about data conversions for data types
newer than release 7.3 is listed here:
•

REFs stored in the database are converted to SQLT_REF on output.

•

SQLT_REF is converted to the internal representation of REFs on input.

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Data Conversions

•

Named data types stored in the database can be converted to SQLT_NTY (and
represented by a C struct in the application) on output.

•

SQLT_NTY (represented by a C struct in an application) is converted to the internal

representation of the corresponding type on input.
LOBs are shown in Table 5-6, because of the width limitation.

See Also:
Object-Relational Data Types in OCI for information about OCIString,
OCINumber, and other new data types

Table 5-5

Data Conversions

NA1

INTERNAL
DATA
TYPES->

EXTERNAL
VARCHAR2
DATA TYPES

NA

NA

NA

NA

NA

NA

NA

NA

NUMBER

LONG

ROWID

UROWID

DATE

RAW

LONG
RAW

CHAR

I/O

I/O

I/O3

I/O3

I/O4

I/O5

I/O5

NA

NA

NA

NA

NA

NA

I/O6

VARCHAR2

I/O2

NUMBER

I/O6

I/O

I7

INTEGER

I/O6

I/O

I

NA

NA

NA

NA

NA

I/O6

FLOAT

I/O6

I/O

I

NA

NA

NA

NA

NA

I/O6

STRING

I/O

I/O

I/O

I/O3

I/O3

I/O4

I/O5

I/O5,8

I/O

VARNUM

I/O6

I/O

I

NA

NA

NA

NA

NA

I/O6

DECIMAL

I/O6

I/O

I

NA

NA

NA

NA

NA

I/O6

LONG

I/O

I/O

I/O

I/O3

I/O3

I/O4

I/O5

I/O5,8

I/O

I/O3

I/O4

I/O5

I/O5,8

I/O

VARCHAR

I/O

I/O

I/O

I/O3

DATE

I/O

NA

I

NA

NA

I/O

NA

NA

I/O

VARRAW

I/O9

NA

I8,9

NA

NA

NA

I/O

I/O

I/O9

RAW

I/O9

NA

I8,9

NA

NA

NA

I/O

I/O

I/O9

LONG RAW

O10,9

NA

I8,9

NA

NA

NA

I/O

I/O

O9

UNSIGNED

I/O6

I/O

I

NA

NA

NA

NA

NA

I/O6

LONG VARCHAR

I/O

I/O

I/O

I/O3

I/O3

I/O4

I/O5

I/O5,8

I/O

LONG VARRAW

I/O9

NA

I8,9

NA

NA

NA

I/O

I/O

I/O9

CHAR

I/O

I/O

I/O

I/O3

I/O3

I/O4

I/O5

I5

I/O

CHARZ

I/O

I/O

I/O

I/O3

I/O3

I/O4

I/O5

I5

I/O

ROWID
descriptor

I3

NA

NA

I/O

I/O

NA

NA

NA

I3

1
2
3
4

NA means not applicable.
I/O = Conversion is valid for input or output.
For input, host string must be in Oracle ROWID/UROWID format. On output, column value is returned in Oracle ROWID/
UROWID format.
For input, host string must be in the Oracle DATE character format. On output, column value is returned in Oracle DATE format.

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9

For input, host string must be in hexadecimal format. On output, column value is returned in hexadecimal format.
For output, column value must represent a valid number.
I = Conversion is valid for input only.
Length must be less than or equal to 2000.
On input, column value is stored in hexadecimal format. On output, column value must be in hexadecimal format.

1

O = Conversion is valid for output only.

5
6
7
8

0

This section includes the following topics:
•

Data Conversions for LOB Data Type Descriptors

•

Data Conversions for Datetime and Interval Data Types

•

Datetime and Date Upgrading Rules

•

Data Conversion for BINARY_FLOAT and BINARY_DOUBLE in OCI

5.4.1 Data Conversions for LOB Data Type Descriptors
Shows the data conversions for LOBs.
Table 5-6 shows the data conversions for LOBs. For example, the external character
data types (VARCHAR, CHAR, LONG, and LONG VARCHAR) convert to the internal CLOB data
type, whereas the external raw data types (RAW, VARRAW, LONG RAW, and LONG VARRAW)
convert to the internal BLOB data type.
Table 5-6

Data Conversions for LOBs

EXTERNAL DATA TYPES

INTERNAL CLOB

INTERNAL BLOB

VARCHAR

I/O1

NA2

CHAR

I/O

NA

LONG

I/O

NA

LONG VARCHAR

I/O

NA

RAW

NA

I/O

VARRAW

NA

I/O

LONG RAW

NA

I/O

LONG VARRAW

NA

I/O

1
2

I/O = Conversion is valid for input or output.
NA means not applicable.

5.4.2 Data Conversions for Datetime and Interval Data Types
Shows the data conversion for datetime and interval data types.
You can also use one of the character data types for the host variable used in a fetch
or insert operation from or to a datetime or interval column. Oracle Database does the
conversion between the character data type and datetime or interval data type for you
(see Table 5-7.

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Table 5-7

Data Conversion for Datetime and Interval Types

External Types/Internal
Types

VARCHAR,
CHAR

DATE

TS

TSTZ

TSLTZ

INTERVAL
YEAR TO
MONTH

INTERVAL
DAY TO
SECOND

VARCHAR2, CHAR

I/O1

I/O

I/O

I/O

I/O

I/O

I/O
NA

DATE

I/O

I/O

I/O

I/O

I/O

NA2

OCI DATE

I/O

I/O

I/O

I/O

I/O

NA

NA

ANSI DATE

I/O

I/O

I/O

I/O

I/O

NA

NA

TIMESTAMP (TS)

I/O

I/O

I/O

I/O

I/O

NA

NA

TIMESTAMP WITH TIME ZONE
(TSTZ)

I/O

I/O

I/O

I/O

I/O

NA

NA

TIMESTAMP WITH LOCAL TIME
ZONE (TSLTZ)

I/O

I/O

I/O

I/O

I/O

NA

NA

INTERVAL YEAR TO MONTH

I/O

NA

NA

NA

NA

I/O

NA

INTERVAL DAY TO SECOND

I/O

NA

NA

NA

NA

NA

I/O

1
2

I/O = Conversion is valid for input or output.
NA means not applicable.

This section includes the following topics:
•

Assignment Notes

•

Data Conversion Notes for Datetime and Interval Types

5.4.2.1 Assignment Notes
When you assign a source with a time zone to a target without a time zone, the time
zone portion of the source is ignored.
When you assign a source without a time zone to a target with a time zone, the time
zone of the target is set to the session's default time zone.
When you assign an Oracle Database DATE to a TIMESTAMP, the TIME portion of the DATE
is copied over to the TIMESTAMP. When you assign a TIMESTAMP to Oracle Database DATE,
the TIME portion of the result DATE is set to zero. This is done to encourage upgrading of
Oracle Database DATE to ANSI-compliant DATETIME data types.
When you assign an ANSI DATE to an Oracle DATE or a TIMESTAMP, the TIME portion of the
Oracle Database DATE and the TIMESTAMP are set to zero. When you assign an Oracle
Database DATE or a TIMESTAMP to an ANSI DATE, the TIME portion is ignored.
When you assign a DATETIME to a character string, the DATETIME is converted using the
session's default DATETIME format. When you assign a character string to a DATETIME,
the string must contain a valid DATETIME value based on the session's default DATETIME
format
When you assign a character string to an INTERVAL, the character string must be a valid
INTERVAL character format.

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5.4.2.2 Data Conversion Notes for Datetime and Interval Types
Describes some information for datetime and interval types.
When you convert from TSLTZ to CHAR, DATE, TIMESTAMP, and TSTZ, the value is adjusted
to the session time zone.
When you convert from CHAR, DATE, and TIMESTAMP to TSLTZ, the session time zone is
stored in memory.
When you assign TSLTZ to ANSI DATE, the time portion is zero.
When you convert from TSTZ, the time zone that the time stamp is in is stored in
memory.
When you assign a character string to an interval, the character string must be a valid
interval character format.

5.4.3 Datetime and Date Upgrading Rules
OCI has full forward and backward compatibility between a client application and the
Oracle database for datetime and date columns.
This section includes the following topics:
•

Pre-9.0 Client with 9.0 or Later Server

•

Pre-9.0 Server with 9.0 or Later Client

5.4.3.1 Pre-9.0 Client with 9.0 or Later Server
The only datetime data type available to a pre-9.0 application is the DATE data type,
SQLT_DAT.
When a pre-9.0 client that defined a buffer as SQLT_DAT tries to obtain data from a TSLTZ
column, only the date portion of the value is returned to the client.

5.4.3.2 Pre-9.0 Server with 9.0 or Later Client
When a pre-9.0 server is used with a 9.0 or later client, the client can have a bind or
define buffer of type SQLT_TIMESTAMP_LTZ.
The following compatibilities are maintained in this case.
If any client application tries to insert a SQLT_TIMESTAMP_LTZ (or any of the new datetime
data types) into a DATE column, an error is issued because there is potential data loss
in this situation.
When a client has an OUT bind or a define buffer that is of data type
SQLT_TIMESTAMP_LTZ and the underlying server-side SQL buffer or column is of DATE
type, then the session time zone is assigned.

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5.4.4 Data Conversion for BINARY_FLOAT and BINARY_DOUBLE in
OCI
Shows the supported conversions between internal numeric data types and all
relevant external types.
Table 5-8 shows the supported conversions between internal numeric data types and
all relevant external types. An (I) implies that the conversion is valid for input only
(binds), and (O) implies that the conversion is valid for output only (defines). An (I/O)
implies that the conversion is valid for input and output (binds and defines).
Table 5-8
Types

Data Conversion for External Data Types to Internal Numeric Data

External Types/Internal Types

BINARY_FLOAT

BINARY_DOUBLE

VARCHAR

I/O1

I/O

VARCHAR2

I/O

I/O

NUMBER

I/O

I/O

INTEGER

I/O

I/O

FLOAT

I/O

I/O

STRING

I/O

I/O

VARNUM

I/O

I/O

LONG

I/O

I/O

UNSIGNED INT

I/O

I/O

LONG VARCHAR

I/O

I/O

CHAR

I/O

I/O

BINARY_FLOAT

I/O

I/O

BINARY_DOUBLE

I/O

I/O

1

An (I/O) implies that the conversion is valid for input and output (binds and defines)

Table 5-9 shows the supported conversions between all relevant internal types and
numeric external types. An (I) implies that the conversion is valid for input only (only
for binds), and (O) implies that the conversion is valid for output only (only for defines).
An (I/O) implies that the conversion is valid for input and output (binds and defines).
Table 5-9

Data Conversions for Internal to External Numeric Data Types

Internal Types/External Types

Native Float

Native Double

VARCHAR2

I/O1

I/O

NUMBER

I/O

I/O

LONG

I2

I

CHAR

I/O

I/O

BINARY_FLOAT

I/O

I/O

BINARY_DOUBLE

I/O

I/O

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Typecodes

1
2

An (I/O) implies that the conversion is valid for input and output (binds and defines)
An (I) implies that the conversion is valid for input only (only for binds)

5.5 Typecodes
A unique typecode is associated with each Oracle Database type, whether scalar,
collection, reference, or object type.
This typecode identifies the type, and is used by Oracle Database to manage
information about object type attributes. This typecode system is designed to be
generic and extensible. It is not tied to a direct one-to-one mapping to Oracle data
types. Consider the following SQL statements:
CREATE TYPE my_type AS OBJECT
( attr1
NUMBER,
attr2
INTEGER,
attr3
SMALLINT);
CREATE TABLE my_table AS TABLE OF my_type;

These statements create an object type and an object table. When it is created,
my_table has three columns, all of which are of Oracle NUMBER type, because SMALLINT
and INTEGER map internally to NUMBER. The internal representation of the attributes of
my_type, however, maintains the distinction between the data types of the three
attributes: attr1 is OCI_TYPECODE_NUMBER, attr2 is OCI_TYPECODE_INTEGER, and attr3 is
OCI_TYPECODE_SMALLINT. If an application describes my_type, these typecodes are

returned.
OCITypeCode is the C data type of the typecode. The typecode is used by some OCI
functions, like OCIObjectNew(), where it helps determine what type of object is
created. It is also returned as the value of some attributes when an object is described;
for example, querying the OCI_ATTR_TYPECODE attribute of a type returns an OCITypeCode
value.

Table 5-10 lists the possible values for an OCITypeCode. There is a value corresponding
to each Oracle data type.
Table 5-10

OCITypeCode Values and Data Types

Value

Data Type

OCI_TYPECODE_REF

REF

OCI_TYPECODE_DATE

DATE

OCI_TYPECODE_TIMESTAMP

TIMESTAMP

OCI_TYPECODE_TIMESTAMP_TZ

TIMESTAMP WITH TIME ZONE

OCI_TYPECODE_TIMESTAMP_LTZ

TIMESTAMP WITH LOCAL TIME ZONE

OCI_TYPECODE_INTERVAL_YM

INTERVAL YEAR TO MONTH

OCI_TYPECODE_INTERVAL_DS

INTERVAL DAY TO SECOND

OCI_TYPECODE_REAL

Single-precision real

OCI_TYPECODE_DOUBLE

Double-precision real

OCI_TYPECODE_FLOAT

Floating-point

OCI_TYPECODE_NUMBER

Oracle NUMBER

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Table 5-10

(Cont.) OCITypeCode Values and Data Types

Value

Data Type

OCI_TYPECODE_BFLOAT

BINARY_FLOAT

OCI_TYPECODE_BDOUBLE

BINARY_DOUBLE

OCI_TYPECODE_DECIMAL

Decimal

OCI_TYPECODE_OCTET

Octet

OCI_TYPECODE_INTEGER

Integer

OCI_TYPECODE_SMALLINT

Small int

OCI_TYPECODE_RAW

RAW

OCI_TYPECODE_VARCHAR2

Variable string ANSI SQL, that is, VARCHAR2

OCI_TYPECODE_VARCHAR

Variable string Oracle SQL, that is, VARCHAR

OCI_TYPECODE_CHAR

Fixed-length string inside SQL, that is SQL CHAR

OCI_TYPECODE_VARRAY

Variable-length array (varray)

OCI_TYPECODE_TABLE

Multiset

OCI_TYPECODE_CLOB

Character large object (CLOB)

OCI_TYPECODE_BLOB

Binary large object (BLOB)

OCI_TYPECODE_BFILE

Binary large object file (BFILE)

OCI_TYPECODE_OBJECT

Named object type, or SYS.XMLType

OCI_TYPECODE_NAMEDCOLLECTION

Collection

OCI_TYPECODE_BOOLEAN1

Boolean

OCI_TYPECODE_RECORD1

Record

OCI_TYPECODE_ITABLE1

Index-by BINARY_INTEGER

OCI_TYPECODE_INTEGER1

PLS_INTEGER or BINARY_INTEGER

1

This type is a PL/SQL type only.

This section includes the following topic: Relationship Between SQLT and
OCI_TYPECODE Values.

5.5.1 Relationship Between SQLT and OCI_TYPECODE Values
Oracle Database recognizes two different sets of data type code values.
One set is distinguished by the SQLT_ prefix, the other by the OCI_TYPECODE_ prefix.
The SQLT typecodes are used by OCI to specify a data type in a bind or define
operation, enabling you to control data conversions between Oracle Database and
OCI client applications. The OCI_TYPECODE types are used by Oracle's type system to
reference or describe predefined types when manipulating or creating user-defined
types.
In many cases, there are direct mappings between SQLT and OCI_TYPECODE values. In
other cases, however, there is not a direct one-to-one mapping. For example,
OCI_TYPECODE_SIGNED8, OCI_TYPECODE_SIGNED16, OCI_TYPECODE_SIGNED32,

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Typecodes

OCI_TYPECODE_INTEGER, OCI_TYPECODE_OCTET, and OCI_TYPECODE_SMALLINT are all mapped
to the SQLT_INT type.

Table 5-11 illustrates the mappings between SQLT and OCI_TYPECODE types.
Table 5-11

OCI_TYPECODE to SQLT Mappings

Oracle Type System Typename

Oracle Type System Type

Equivalent SQLT Type

BFILE

OCI_TYPECODE_BFILE

SQLT_BFILE

BLOB

OCI_TYPECODE_BLOB

SQLT_BLOB

BOOLEAN1

OCI_TYPECODE_BOOLEAN

SQLT_BOL

CHAR

OCI_TYPECODE_CHAR (n)

SQLT_AFC(n)2

CLOB

OCI_TYPECODE_CLOB

SQLT_CLOB

COLLECTION

OCI_TYPECODE_NAMEDCOLLECTION

SQLT_NCO

DATE

OCI_TYPECODE_DATE

SQLT_DAT

TIMESTAMP

OCI_TYPECODE_TIMESTAMP

SQLT_TIMESTAMP

TIMESTAMP WITH TIME ZONE

OCI_TYPECODE_TIMESTAMP_TZ

SQLT_TIMESTAMP_TZ

TIMESTAMP WITH LOCAL TIME ZONE

OCI_TYPECODE_TIMESTAMP_LTZ

SQLT_TIMESTAMP_LTZ

INTERVAL YEAR TO MONTH

OCI_TYPECODE_INTERVAL_YM

SQLT_INTERVAL_YM

INTERVAL DAY TO SECOND

OCI_TYPECODE_INTERVAL_DS

SQLT_INTERVAL_DS

FLOAT

OCI_TYPECODE_FLOAT (b)

SQLT_FLT (8)3

DECIMAL

OCI_TYPECODE_DECIMAL (p)

SQLT_NUM (p, 0)4

DOUBLE

OCI_TYPECODE_DOUBLE

SQLT_FLT (8)

BINARY_FLOAT

OCI_TYPECODE_BFLOAT

SQLT_BFLOAT

BINARY_DOUBLE

OCI_TYPECODE_BDOUBLE

SQLT_BDOUBLE

OCI_TYPECODE_ITABLE

SQLT_NTY

INTEGER

OCI_TYPECODE_INTEGER

SQLT_INT (i)5

NUMBER

OCI_TYPECODE_NUMBER (p, s)

SQLT_NUM (p, s)6

OCI_TYPECODE_OCTET

SQLT_INT (1)

OCI_TYPECODE_PLS_INTEGER

SQLT_INT

POINTER

OCI_TYPECODE_PTR



RAW

OCI_TYPECODE_RAW

SQLT_LVB

REAL

OCI_TYPECODE_REAL

SQLT_FLT (4)

REF

OCI_TYPECODE_REF

SQLT_REF

RECORD1

OCI_TYPECODE_RECORD

SQLT_NTY

OBJECT or SYS.XMLType

OCI_TYPECODE_OBJECT

SQLT_NTY

SIGNED(8)

OCI_TYPECODE_SIGNED8

SQLT_INT (1)

SIGNED(16)

OCI_TYPECODE_SIGNED16

SQLT_INT (2)

SIGNED(32)

OCI_TYPECODE_SIGNED32

SQLT_INT (4)

SMALLINT

OCI_TYPECODE_SMALLINT

SQLT_INT (i)5

TABLE7

OCI_TYPECODE_TABLE



UNSIGNED(8)

OCI_TYPECODE_UNSIGNED8

SQLT_UIN (1)

INDEX-BY

BINARY_INTEGER1

OCTET
PLS_INTEGER or

BINARY_INTEGER1

5-36

Chapter 5

Definitions in oratypes.h

Table 5-11

(Cont.) OCI_TYPECODE to SQLT Mappings

Oracle Type System Typename

Oracle Type System Type

Equivalent SQLT Type

UNSIGNED(16)

OCI_TYPECODE_UNSIGNED16

SQLT_UIN (2)

UNSIGNED(32)

OCI_TYPECODE_UNSIGNED32

SQLT_UIN (4)

VARRAY7

OCI_TYPECODE_VARRAY



VARCHAR

OCI_TYPECODE_VARCHAR (n)

SQLT_CHR (n)2

VARCHAR2

OCI_TYPECODE_VARCHAR2 (n)

SQLT_VCS (n)2

1
2
3
4
5
6
7

This type is a PL/SQL type only.
n is the size of the string in bytes.
These are floating-point numbers, the precision is given in terms of binary digits. b is the precision of the number in binary
digits.
This is equivalent to a NUMBER with no decimal places.
i is the size of the number in bytes, set as part of an OCI call.
p is the precision of the number in decimal digits; s is the scale of the number in decimal digits.
Can only be part of a named collection type.

5.6 Definitions in oratypes.h
Describes the contents of the oratypes.h header file.
Throughout this guide there are references to data types like ub2 or sb4, or to constants
like UB4MAXVAL. These types are defined in the oratypes.h header file, which is found in
the public directory. The exact contents may vary according to the operating system
that you are using.

Note:
The use of the data types in oratypes.h is the only supported means of
supplying parameters to OCI.

5-37

6
Using SQL Statements in OCI
This chapter discusses the concepts and steps involved in processing SQL statements
with Oracle Call Interface.
This chapter contains these topics:
•

Overview of SQL Statement Processing

•

About Preparing Statements

•

About Binding Placeholders in OCI

•

About Executing Statements

•

About Describing Select-List Items

•

About Defining Output Variables in OCI

•

About Fetching Results

•

About Using Scrollable Cursors in OCI

6.1 Overview of SQL Statement Processing
One of the most common tasks of an OCI program is to accept and process SQL
statements.
Chapter 3 “OCI Programming Basics” discussed the basic steps involved in any OCI
application. This chapter presents a more detailed look at the specific tasks involved in
processing SQL statements in an OCI program.
This section outlines the specific steps involved in accepting and processing SQL
statements.
Once you have allocated the necessary handles and connected to an Oracle
database, follow the steps illustrated in Figure 6-1.

6-1

Chapter 6

Overview of SQL Statement Processing

Figure 6-1

Steps in Processing SQL Statements

1.

Prepare the statement. Define an application request using OCIStmtPrepare2().
OCIStmtPrepare2() is an enhanced version of OCIStmtPrepare() that was introduced
to support statement caching. Beginning with Oracle Database 12c Release 2
(12.2), OCIStmtPrepare() is deprecated.

2.

Bind placeholders, if necessary. For DML statements and queries with input
variables, perform one or more of the following bind calls to bind the address of
each input variable (or PL/SQL output variable) or array to each placeholder in the
statement.
•

OCIBindByPos2() or OCIBindByPos()

•

OCIBindByName2() or OCIBindByName()

•

OCIBindObject()

•

OCIBindDynamic()

•

OCIBindArrayOfStruct()

3.

Execute the statement by calling OCIStmtExecute(). For DDL statements, no further
steps are necessary.

4.

Describe the select-list items, if necessary, usingOCIParamGet() and OCIAttrGet().
This is optional step is not required if the number of select-list items and the
attributes of each item (such as its length and data type) are known at compile
time.

5.

Define output variables, if necessary. For queries, perform one or more define
calls to OCIDefineByPos2() or OCIDefineByPos(), , OCIDefineObject(),
OCIDefineDynamic(), or OCIDefineArrayOfStruct() to define an output variable for
each select-list item in the SQL statement. Note that you do not use a define call

6-2

Chapter 6

Overview of SQL Statement Processing

to define the output variables in an anonymous PL/SQL block. You did this when
you bound the data.
6.

Fetch the results of the query, if necessary, by calling OCIStmtFetch2().

After these steps have been completed, the application can free allocated handles and
then detach from the server, or it may process additional statements.

Note:
OCI programs no longer require an explicit parse step. If a statement must
be parsed, that step occurs upon execution, meaning that release 8.0 or later
applications must issue an execute command for both DML and DDL
statements.

The following sections describe each step in detail.

Note:
Some variation in the order of steps is possible. For example, it is possible to
do the define step before the execute step if the data types and lengths of
returned values are known at compile time.

Additional steps beyond those listed earlier may be required if your application must
do any of the following:
•

Initiate and manage multiple transactions

•

Manage multiple threads of execution

•

Perform piecewise inserts, updates, or fetches

6-3

Chapter 6

About Preparing Statements

See Also:
•

Statement Caching in OCI

•

OCI Programming Basics

•

OCIStmtPrepare2() or OCIStmtPrepare()

•

OCIBindByPos2() or OCIBindByPos()

•

OCIBindByName2() or OCIBindByName()

•

OCIBindObject()

•

OCIBindDynamic()

•

OCIBindArrayOfStruct()

•

OCIStmtExecute()

•

OCIParamGet()

•

OCIAttrGet()

•

OCIDefineByPos2() or OCIDefineByPos()

•

OCIDefineObject()

•

OCIDefineDynamic()

•

OCIDefineArrayOfStruct()

•

OCIStmtFetch2()

6.2 About Preparing Statements
SQL and PL/SQL statements are prepared for execution by using the statement
prepare call and any necessary bind calls.
In this phase, the application specifies a SQL or PL/SQL statement and binds
associated placeholders in the statement to data for execution. The client-side library
allocates storage to maintain the statement prepared for execution.
An application requests a SQL or PL/SQL statement to be prepared for execution
using the OCIStmtPrepare2() call and passes to this call a previously allocated
statement handle. This is a completely local call, requiring no round-trip to the server.
No association is made between the statement and a particular server at this point.
Following the request call, an application can call OCIAttrGet() on the statement
handle, passing OCI_ATTR_STMT_TYPE to the attrtype parameter, to determine what type
of SQL statement was prepared. The possible attribute values and corresponding
statement types are listed in Table 6-1.
Table 6-1

OCI_ATTR_STMT_TYPE Values and Statement Types

Attribute Value

Statement Type

OCI_STMT_SELECT

SELECT statement

OCI_STMT_UPDATE

UPDATE statement

6-4

Chapter 6

About Preparing Statements

Table 6-1

(Cont.) OCI_ATTR_STMT_TYPE Values and Statement Types

Attribute Value

Statement Type

OCI_STMT_DELETE

DELETE statement

OCI_STMT_INSERT

INSERT statement

OCI_STMT_CREATE

CREATE statement

OCI_STMT_DROP

DROP statement

OCI_STMT_ALTER

ALTER statement

OCI_STMT_BEGIN

BEGIN... (PL/SQL)

OCI_STMT_DECLARE

DECLARE... (PL/SQL)

OCI_STMT_CALL

CALL... (PL/SQL)

OCI_STMT_MERGE

MERGE... (PL/SQL)

This section includes the following topic: About Using Prepared Statements on Multiple
Servers

See Also:
•

OCIStmtPrepare2()

•

OCIAttrGet()

•

About Using PL/SQL in an OCI Program

6.2.1 About Using Prepared Statements on Multiple Servers
A prepared application request can be executed on multiple servers at run time by
reassociating the statement handle with the respective service context handles for the
servers.
All information about the current service context and statement handle association is
lost when a new association is made.
For example, consider an application such as a network manager, which manages
multiple servers. In many cases, it is likely that the same SELECT statement must be
executed against multiple servers to retrieve information for display. OCI allows the
network manager application to prepare a SELECT statement once and execute it
against multiple servers. It must fetch all of the required rows from each server before
reassociating the prepared statement with the next server.

Note:
If a prepared statement must be reexecuted frequently on the same server, it
is more efficient to prepare a new statement for another service context.

6-5

Chapter 6

About Binding Placeholders in OCI

6.3 About Binding Placeholders in OCI
Most DML statements, and some queries (such as those with a WHERE clause), require
a program to pass data to Oracle Database as part of a SQL or PL/SQL statement.
This data can be constant or literal, known when your program is compiled. For
example, the following SQL statement, which adds an employee to a database,
contains several literals, such as 'BESTRY' and 2365:
INSERT INTO emp VALUES
(2365, 'BESTRY', 'PROGRAMMER', 2000, 20)

Coding a statement like this into an application would severely limit its usefulness. You
must change the statement and recompile the program each time you add a new
employee to the database. To make the program more flexible, you can write the
program so that a user can supply input data at run time.
When you prepare a SQL statement or PL/SQL block that contains input data to be
supplied at run time, placeholders in the SQL statement or PL/SQL block mark where
data must be supplied. For example, the following SQL statement contains five
placeholders, indicated by the leading colons (:ename), that show where input data
must be supplied by the program.
INSERT INTO emp VALUES
(:empno, :ename, :job, :sal, :deptno)

You can use placeholders for input variables in any DELETE, INSERT, SELECT, or UPDATE
statement, or in a PL/SQL block, in any position in the statement where you can use
an expression or a literal value. In PL/SQL, placeholders can also be used for output
variables.
Placeholders cannot be used to represent other Oracle objects such as tables. For
example, the following is not a valid use of the emp placeholder:
INSERT INTO :emp VALUES
(12345, 'OERTEL', 'WRITER', 50000, 30)

For each placeholder in a SQL statement or PL/SQL block, you must call an OCI
routine that binds the address of a variable in your program to that placeholder. When
the statement executes, the database gets the data that your program placed in the
input variables or bind variables and passes it to the server with the SQL statement.
Binding is used for both input and output variables in nonquery operations. In
Example 6-1, the variables empno_out, ename_out, job_out, sal_out, and deptno_out
should be bound. These are outbinds (as opposed to regular inbinds).
Example 6-1

Binding Both Input and Output Variables in Nonquery Operations

INSERT INTO emp VALUES
(:empno, :ename, :job, :sal, :deptno)
RETURNING
(empno, ename, job, sal, deptno)
INTO
(:empno_out, :ename_out, :job_out, :sal_out, :deptno_out)

This section includes the following topic: Rules for Placeholders

6-6

Chapter 6

About Executing Statements

See Also:
Binding and Defining in OCI for detailed information about implementing bind
operations

6.3.1 Rules for Placeholders
Lists and describes the rules for forming placeholders.
The rules for forming placeholders are as follows:
•

The first character is a colon (":").

•

The colon is followed by a combination of underscore ("_"), A to Z, a to z, or 0 to 9.
However, the first character following the colon cannot be an underscore.

•

The letters must be only from the English alphabet, and only the first 30 characters
after the colon are significant. The name is case-insensitive.

•

The placeholder can consist of only digits after the colon. If it is only digits, the
placeholder must be less than 65536. If the name starts with a digit, then only
digits are allowed.

•

The hyphen ("-") is not allowed.

6.4 About Executing Statements
An OCI application executes prepared statements individually using OCIStmtExecute().
When an OCI application executes a query, it receives from the Oracle database data
that matches the query specifications. Within the database, the data is stored in
Oracle-defined formats. When the results are returned, the OCI application can
request that data be converted to a particular host language format, and stored in a
particular output variable or buffer.
For each item in the select list of a query, the OCI application must define an output
variable to receive the results of the query. The define step indicates the address of
the buffer and the type of the data to be retrieved.

Note:
If output variables are defined for a SELECT statement before a call to
OCIStmtExecute(), the number of rows specified by the iters parameter are
fetched directly into the defined output buffers and additional rows equivalent
to the prefetch count are prefetched. If there are no additional rows, then the
fetch is complete without calling OCIStmtFetch2().

For nonqueries, the number of times the statement is executed during array operations
equals iters - rowoff, where rowoff is the offset in the bound array, and is also a
parameter of the OCIStmtExecute() call.

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Chapter 6

About Executing Statements

For example, if an array of 10 items is bound to a placeholder for an INSERT statement,
and iters is set to 10, all 10 items are inserted in a single execute call when rowoff is
zero. If rowoff is set to 2, only 8 items are inserted.
This section includes the following topics:
•

Execution Snapshots

•

Execution Modes of OCIStmtExecute()

See Also:
•

OCIStmtExecute()

•

OCIStmtFetch2()

•

About Defining Output Variables in OCI

6.4.1 Execution Snapshots
The OCIStmtExecute() call provides the ability to ensure that multiple service contexts
operate on the same consistent snapshot of the database's committed data.
This is achieved by taking the contents of the snap_out parameter of one
OCIStmtExecute() call and passing that value as the snap_in parameter of the next
OCIStmtExecute() call.

Note:
Uncommitted data in one service context is not visible to another context,
even when both calls are using the same snapshot.

The data type of both the snap_out and snap_in parameter is OCISnapshot. OCISnapshot
is an OCI snapshot descriptor that is allocated with the OCIDescriptorAlloc() function.
It is not necessary to specify a snapshot when calling OCIStmtExecute(). The following
sample code shows a basic execution in which the snapshot parameters are passed as
NULL.
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4) 0,
(OCISnapshot *)NULL, (OCISnapshot *) NULL, OCI_DEFAULT));

Note:
The checkerr() function, which is user-developed, evaluates the return code
from an OCI application.

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Chapter 6

About Executing Statements

See Also:
•

OCIStmtExecute()

•

OCIDescriptorAlloc()

•

OCI Descriptors

6.4.2 Execution Modes of OCIStmtExecute()
You can specify a number of modes for the OCIStmtExecute() call.
This section describes the OCIStmtExecute() call. See OCIStmtExecute() for other
values of the parameter mode.
This section includes the following topics:
•

Using Batch Error Mode

•

Example of Batch Error Mode

See Also:
OCIStmtExecute()

6.4.2.1 Using Batch Error Mode
OCI provides the ability to perform array DML operations.
For example, an application can process an array of INSERT, UPDATE, or DELETE
statements with a single statement execution. If one of the operations fails due to an
error from the server, such as a unique constraint violation, the array operation
terminates, and OCI returns an error. Any rows remaining in the array are ignored. The
application must then reexecute the remainder of the array, and go through the whole
process again if it encounters more errors, which causes additional round-trips.
To facilitate processing of array DML operations, OCI provides the batch error mode
(also called the enhanced DML array feature). This mode, which is specified in the
OCIStmtExecute() call, simplifies DML array processing if there are one or more errors.
In this mode, OCI attempts to insert, update, or delete all rows, and collects
information about any errors that occurred. The application can then retrieve error
information and reexecute any DML operations that failed during the first call. In this
way, all DML operations in the array are attempted in the first call, and any failed
operations can be reissued in a second call.

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Chapter 6

About Executing Statements

Note:
This feature is only available to applications linked with release 8.1 or later
OCI libraries running against a release 8.1 or later server. Applications must
also be recoded to account for the new program logic described in this
section.

This mode is used as follows:
1.

The user specifies OCI_BATCH_ERRORS as the mode parameter of the
OCIStmtExecute() call.

2.

After performing an array DML operation with OCIStmtExecute(), the application
can retrieve the number of errors encountered during the operation by calling
OCIAttrGet() on the statement handle to retrieve the OCI_ATTR_NUM_DML_ERRORS
attribute, as shown in the following code example.
Calling OCIAttrGet() to Retrieve the Number of Errors Encountered During an
Array DML Operation
ub4 num_errs;
OCIAttrGet(stmtp, OCI_HTYPE_STMT, &num_errs, 0, OCI_ATTR_NUM_DML_ERRORS,
errhp);

3.

The application extracts each error using OCIParamGet(), along with its row
information, from the error handle that was passed to the OCIStmtExecute() call. To
retrieve the information, the application must allocate an additional new error
handle for the OCIParamGet() call, populating the new error handle with batched
error information. The application obtains the syntax of each error with
OCIErrorGet(), and the row offset into the DML array at which the error occurred,
by calling OCIAttrGet() on the new error handle.
For example, after the num_errs amount has been retrieved, the application can
issue the following calls shown in the following code example.
Retrieving Information About Each Error Following an Array DML Operation
OCIError errhndl, errhp2;
for (i=0; i :some_value
AND comm > :some_value

An OCI application could complete the binds for this statement with a single call to
OCIBindByName() or OCIBindByName2() to bind the :some_value placeholder by name. In
this case, all bind placeholders for :some_value get assigned the same value as
provided by the OCIBindByName() or OCIBindByName2() call.
Now consider the case where a 6th placeholder is added that is a duplicate. For
example, add :ename as the 6th placeholder in the first previous example:
INSERT INTO emp VALUES
(:empno, :ename, :job, :sal, :deptno, :ename)

If you are using the OCIBindByName() or OCIBindByName2() call, just one bind call suffices
to bind both occurrences of the :ename placeholder. All occurrences of :ename in the
statement will get bound to the same value. Moreover, if new bind placeholders get

7-3

Chapter 7

Overview of Binding in OCI

added as a result of which bind positions for existing bind placeholders change, you do
not need to change your existing bind calls in order to update bind positions. This is a
distinct advantage in using the OCIBindByName() or OCIBindByName2() call if your program
evolves to add more bind variables in your statement text.
If you are using the OCIBindByPos() or OCIBindByPos2() call, however, you have
increased flexibility in terms of binding duplicate bind-parameters separately, if you
need it. You have the option of binding any of the duplicate occurrences of a bind
parameter separately. Any unbound duplicate occurrences of a parameter inherit the
value from the first occurrence of the bind parameter with the same name. The first
occurrence must be explicitly bound.
In the context of SQL statements, the position n indicates the bind parameter at the
nth position. However, in the context of PL/SQL statements, OCIBindByPos() or
OCIBindByPos2() has a different interpretation for the position parameter: the position n
in the bind call indicates a binding for the nth unique parameter name in the statement
when scanned left to right.
Using the previous example again and the same SQL statement text, if you want to
bind the 6th position separately, the :ename placeholder would be bound by calling
OCIBindByPos() or OCIBindByPos2() with a position of 6. Otherwise, if left
unbound, :ename would inherit the value from the first occurrence of the bind parameter
with the same name, in this case, from :ename in position 2.

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

7.1.2 OCI Array Interface
You can pass data to the Oracle database in various ways.
You can execute a SQL statement repeatedly using the OCIStmtExecute() routine and
supply different input values on each iteration.
You can use the Oracle array interface and input many values with a single statement
and a single call to OCIStmtExecute(). In this case, you bind an array to an input
placeholder, and the entire array can be passed at the same time, under the control of
the iters parameter.
The array interface significantly reduces round-trips to the database when you are
updating or inserting a large volume of data. This reduction can lead to considerable
performance gains in a busy client/server environment. For example, consider an
application that inserts 10 rows into the database. Calling OCIStmtExecute() 10 times
with single values results in 10 network round-trips to insert all the data. The same
result is possible with a single call to OCIStmtExecute() using an input array, which
involves only one network round-trip.
Beginning with Oracle Database 12c Release 2 (12.2), support is added for Hybrid
Columnar Compression (HCC) with conventional DMLs, so HCC can be used during
array inserts with OCI. HCC conventional array inserts are only supported for HCC
tables on ASSM tablespaces. .

7-4

Chapter 7

Overview of Binding in OCI

Note:
When you use the OCI array interface to perform inserts, row triggers in the
database are fired as each row is inserted.
The maximum number of rows allowed in an array DML statement is 4 billion
-1 (3,999,999,999). However, if you use ub8 instead of ub4, this increases the
maximum number of rows allowed in an array DML statement to be more
than 4 billion rows.

See Also:
•

OCIStmtExecute()

•

About Table Compression in Oracle Database Administrator’s Guide for
information about how to configure HCC

7.1.3 About Binding Placeholders in PL/SQL
You process a PL/SQL block by placing the block in a string variable, binding any
variables, and then executing the statement containing the block, just as you would
with a single SQL statement.
When you bind placeholders in a PL/SQL block to program variables, you must use
OCIBindByName() or OCIBindByName2() or OCIBindByPos() or OCIBindByPos2() to perform

the basic binds for host variables that are either scalars or arrays.
The following short PL/SQL block contains two placeholders, which represent IN
parameters to a procedure that updates an employee's salary, when given the
employee number and the new salary amount:
char plsql_statement[] = "BEGIN\
RAISE_SALARY(:emp_number, :new_sal);\
END;" ;

These placeholders can be bound to input variables in the same way as placeholders
in a SQL statement.
When processing PL/SQL statements, output variables are also associated with
program variables by using bind calls.
For example, consider the following PL/SQL block:
BEGIN
SELECT ename,sal,comm INTO :emp_name, :salary, :commission
FROM emp
WHERE empno = :emp_number;
END;

In this block, you would use OCIBindByName() or OCIBindByName2() to bind variables in
place of the :emp_name, :salary, and :commission output placeholders, and in place of
the input placeholder :emp_number.

7-5

Chapter 7

Overview of Binding in OCI

Note:
All buffers, even pure OUT buffers, must be initialized by setting the buffer
length to zero in the bind call, or by setting the corresponding indicator to -1.

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

Information for Named Data Type and REF Binds for more information
about binding PL/SQL placeholders

7.1.4 Steps Used in OCI Binding
Placeholders are bound in several steps.
For a simple scalar or array bind, it is only necessary to specify an association
between the placeholder and the data, by using OCIBindByName() or OCIBindByName2() or
OCIBindByPos() or OCIBindByPos2().
Once the bind is complete, the OCI library detects where to find the input data or
where to put the PL/SQL output data when the SQL statement is executed. Program
input data does not need to be in the program variable when it is bound to the
placeholder, but the data must be there when the statement is executed.
The following code example in Example 7-1 shows handle allocation and binding for
each placeholder in a SQL statement.

Note:
The checkerr() function evaluates the return code from an OCI application.
The code for the function is in the Example for OCIErrorGet().

Example 7-1
Statement

Handle Allocation and Binding for Each Placeholder in a SQL

...
/* The SQL statement, associated with stmthp (the statement handle)
by calling OCIStmtPrepare2() */
text *insert = (text *) "INSERT INTO emp(empno, ename, job, sal, deptno)\
VALUES (:empno, :ename, :job, :sal, :deptno)";
...
/* Bind the placeholders in the SQL statement, one per bind handle. */
checkerr(errhp, OCIBindByName(stmthp, &bnd1p, errhp, (text *) ":ENAME",
strlen(":ENAME"), (ub1 *) ename, enamelen+1, SQLT_STR, (void *) 0,
(ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT));

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Overview of Binding in OCI

checkerr(errhp, OCIBindByName(stmthp, &bnd2p, errhp, (text *) ":JOB",
strlen(":JOB"), (ub1 *) job, joblen+1, SQLT_STR, (void *)
&job_ind, (ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT));
checkerr(errhp, OCIBindByName(stmthp, &bnd3p, errhp, (text *) ":SAL",
strlen(":SAL"), (ub1 *) &sal, (sword) sizeof(sal), SQLT_INT,
(void *) &sal_ind, (ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0,
OCI_DEFAULT));
checkerr(errhp, OCIBindByName(stmthp, &bnd4p, errhp, (text *) ":DEPTNO",
strlen(":DEPTNO"), (ub1 *) &deptno,(sword) sizeof(deptno), SQLT_INT,
(void *) 0, (ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT));
checkerr(errhp, OCIBindByName(stmthp, &bnd5p, errhp, (text *) ":EMPNO",
strlen(":EMPNO"), (ub1 *) &empno, (sword) sizeof(empno), SQLT_INT,
(void *) 0, (ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0,OCI_DEFAULT));

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIErrorGet()

7.1.5 PL/SQL Block in an OCI Program
Perhaps the most common use for PL/SQL blocks in OCI is to call stored procedures
or stored functions.
Assume that there is a procedure named RAISE_SALARY stored in the database, and you
embed a call to that procedure in an anonymous PL/SQL block, and then process the
PL/SQL block.
The following program fragment shows how to embed a stored procedure call in an
OCI application. The program passes an employee number and a salary increase as
inputs to a stored procedure called raise_salary:
raise_salary (employee_num IN, sal_increase IN, new_salary OUT);

This procedure raises a given employee's salary by a given amount. The increased
salary that results is returned in the stored procedure's variable, new_salary, and the
program displays this value.
Note that the PL/SQL procedure argument, new_salary, although a PL/SQL OUT
variable, must be bound, not defined.
Example 7-2 demonstrates how to perform a simple scalar bind where only a single
bind call is necessary. In some cases, additional bind calls are needed to define
attributes for specific bind data types or execution modes.
Example 7-2

Defining a PL/SQL Statement to Be Used in OCI

/* Define PL/SQL statement to be used in program. */
text *give_raise = (text *) "BEGIN\
RAISE_SALARY(:emp_number,:sal_increase,
END;";
OCIBind *bnd1p = NULL;
/* the first
OCIBind *bnd2p = NULL;
/* the second
OCIBind *bnd3p = NULL;
/* the third

:new_salary);\
bind handle */
bind handle */
bind handle */

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static void checkerr();
sb4 status;
main()
{
sword
empno, raise, new_sal;
OCISession *usrhp = (OCISession *)NULL;
...
/* attach to Oracle database, and perform necessary initializations
and authorizations */
...
/* prepare the statement request, passing the PL/SQL text
block as the statement to be prepared */
checkerr(errhp, OCIStmtPrepare2(svchp, &stmthp, errhp, (text *) give_raise, (ub4)
strlen(give_raise), NULL, 0, OCI_NTV_SYNTAX, OCI_DEFAULT));
/* bind each of the placeholders to a program variable */
checkerr( errhp, OCIBindByName(stmthp, &bnd1p, errhp, (text *) ":emp_number",
-1, (ub1 *) &empno,
(sword) sizeof(empno), SQLT_INT, (void *) 0,
(ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT));
checkerr( errhp, OCIBindByName(stmthp, &bnd2p, errhp, (text *) ":sal_increase",
-1, (ub1 *) &raise,
(sword) sizeof(raise), SQLT_INT, (void *) 0,
(ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT));
/* remember that PL/SQL OUT variables are bound, not defined */
checkerr( errhp, OCIBindByName(stmthp, &bnd3p, errhp, (text *) ":new_salary",
-1, (ub1 *) &new_sal,
(sword) sizeof(new_sal), SQLT_INT, (void *) 0,
(ub2 *) 0, (ub2) 0, (ub4) 0, (ub4 *) 0, OCI_DEFAULT));
/* prompt the user for input values */
printf("Enter the employee number: ");
scanf("%d", &empno);
/* flush the input buffer */
myfflush();
printf("Enter employee's raise: ");
scanf("%d", &raise);
/* flush the input buffer */
myfflush();
/* execute PL/SQL block*/
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4) 0,
(OCISnapshot *) NULL, (OCISnapshot *) NULL, OCI_DEFAULT));
/* display the new salary, following the raise */
printf("The new salary is %d\n", new_sal);
OCIStmtRelease(stmthp, errhp, NULL, 0, OCI_DEFAULT);
}

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See Also:
Why a PL/SQL OUT variable must be bound and not defined is explained in
About Defining PL/SQL Output Variables and in Information for Named Data
Type and REF Defines, and PL/SQL OUT Binds.

7.2 Advanced Bind Operations in OCI
More advanced bind operations include multistep binds, and binds of named data
types and REFs.
About Binding Placeholders in OCI discussed how a basic bind operation is performed
to create an association between a placeholder in a SQL statement and a program
variable by using OCIBindByName() or OCIBindByName2() or OCIBindByPos() or
OCIBindByPos2(). This section covers more advanced bind operations, including
multistep binds, and binds of named data types and REFs.
In some cases, additional bind calls are necessary to define specific attributes for
certain bind data types or certain execution modes.
The following sections describe these special cases, and the information about binding
is summarized in Table 7-1.
Table 7-1

Information Summary for Bind Types

Type of Bind

Bind Data Type

Notes

Scalar

Any scalar data type Bind a single scalar using OCIBindByName() or OCIBindByName2()
or OCIBindByPos() or OCIBindByPos2().

Array of scalars

Any scalar data type Bind an array of scalars using OCIBindByName() or
OCIBindByName2() or OCIBindByPos() or OCIBindByPos2().

Named data type

SQLT_NTY

Includes records and collections
Two bind calls are required:
•
•

OCIBindByName() or OCIBindByName2() or OCIBindByPos() or
OCIBindByPos2()
OCIBindObject()

Boolean

SQLT_BOL

Bind a Boolean using OCIBindByName() or OCIBindByName2() or
OCIBindByPos() or OCIBindByPos2().

REF

SQLT_REF

Two bind calls are required:
•
•

OCIBindByName() or OCIBindByName2() or OCIBindByPos() or
OCIBindByPos2()
OCIBindObject()

LOB

SQLT_BLOB

BFILE

SQLT_CLOB

Allocate the LOB locator using OCIDescriptorAlloc(), and then
bind its address, OCILobLocator **, with OCIBindByName() or
OCIBindByName2() or OCIBindByPos() or OCIBindByPos2(), by
using one of the LOB data types.

Array of structures or
static arrays

Varies

Two bind calls are required:
•
•

OCIBindByName() or OCIBindByName2() or OCIBindByPos() or
OCIBindByPos2()
OCIBindArrayOfStruct()

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Table 7-1

(Cont.) Information Summary for Bind Types

Type of Bind

Bind Data Type

Notes

Piecewise insert

Varies

OCIBindByName() or OCIBindByName2() or OCIBindByPos() or
OCIBindByPos2() is required. The application may also need to
call OCIBindDynamic() to register piecewise callbacks.

REF CURSOR variables

SQLT_RSET

Allocate a statement handle, OCIStmt, and then bind its address,
OCIStmt **, using the SQLT_RSET data type.

This section includes the following topics:
•

About Binding LOBs

•

About Binding in OCI_DATA_AT_EXEC Mode

•

About Binding REF CURSOR Variables

See Also:
•

Named Data Type Binds for information about binding named data types
(objects)

•

About Binding REFs

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindObject()

•

OCIDescriptorAlloc()

•

OCIBindArrayOfStruct()

•

OCIBindDynamic()

7.2.1 About Binding LOBs
There are two ways of binding LOBs:
•

Bind the LOB locator, rather than the actual LOB values. In this case the LOB
value is written or read by passing a LOB locator to the OCI LOB functions.

•

Bind the LOB value directly, without using the LOB locator.

This section includes the following topics:
•

Binding LOB Locators

•

About Binding LOB Data

7.2.1.1 Binding LOB Locators
Either a single locator or an array of locators can be bound in a single bind call.

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In each case, the application must pass the address of a LOB locator and not the
locator itself. For example, suppose that an application has prepared this SQL
statement where one_lob is a bind variable corresponding to a LOB column:
INSERT INTO some_table VALUES (:one_lob)

Then your application makes the following declaration:
OCILobLocator * one_lob;

Then the calls in Example 7-3 would be used to bind the placeholder and execute the
statement:
You can also insert an array using the same SQL INSERT statement. In this case, the
application would include the code shown in Example 7-4.
You must allocate descriptors with the OCIDescriptorAlloc() function before they can
be used. In an array of locators, you must initialize each array element using
OCIDescriptorAlloc(). Use OCI_DTYPE_LOB as the type parameter when allocating BLOBs,
CLOBs, and NCLOBs. Use OCI_DTYPE_FILE when allocating BFILEs.
Example 7-3 Binding the Placeholder and Executing the Statement to Insert a
Single Locator
/* initialize single locator */
one_lob = OCIDescriptorAlloc(...OCI_DTYPE_LOB...);
...
/* pass the address of the locator */
OCIBindByName(...,(void *) &one_lob,... SQLT_CLOB, ...);
OCIStmtExecute(...,1,...)
/* 1 is the iters parameter */

Example 7-4 Binding the Placeholder and Executing the Statement to Insert an
Array of Locators
OCILobLocator * lob_array[10];
...
for (i=0; i<10, i++)
lob_array[i] = OCIDescriptorAlloc(...OCI_DTYPE_LOB...);
/* initialize array of locators */
...
OCIBindByName(...,(void *) lob_array,...);
OCIStmtExecute(...,10,...);
/* 10 is the iters parameter */

This section includes the following topic: Restrictions on Binding LOB Locators

See Also:
OCIDescriptorAlloc()

7.2.1.1.1 Restrictions on Binding LOB Locators
What are the restrictions on binding LOB locators.
Observe the following restrictions when you bind LOB locators:
•

Piecewise and callback INSERT or UPDATE operations are not supported.

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•

When using a FILE locator as a bind variable for an INSERT or UPDATE statement,
you must first initialize the locator with a directory object and file name, by using
OCILobFileSetName() before issuing the INSERT or UPDATE statement.

See Also:
•

LOB and BFILE Operations for more information about the OCI LOB
functions

•

OCILobFileSetName()

7.2.1.2 About Binding LOB Data
Oracle Database allows nonzero binds for INSERTs and UPDATEs of any size LOB.
So you can bind data into a LOB column using OCIBindByPos() or OCIBindByPos2(),
OCIBindByName() or OCIBindByName2(), and PL/SQL binds.
The bind of more than 4 kilobytes of data to a LOB column uses space from the
temporary tablespace. Ensure that your temporary tablespace is big enough to hold at
least the amount of data equal to the sum of all the bind lengths for LOBs. If your
temporary tablespace is extendable, it is extended automatically after the existing
space is fully consumed. Use the following command to create an extendable
temporary tablespace:
CREATE TABLESPACE ... AUTOEXTEND ON ... TEMPORARY ...;

This section includes the following topics:
•

Restrictions on Binding LOB Data

•

Examples of Binding LOB Data

See Also:
•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindByName() or OCIBindByName2()

7.2.1.2.1 Restrictions on Binding LOB Data
What are the restrictions on binding LOB data.
Observe the following restrictions when you bind LOB data:
•

If a table has both LONG and LOB columns, then you can have binds of greater than
4 kilobytes for either the LONG column or the LOB columns, but not both in the
same statement.

•

In an INSERT AS SELECT operation, Oracle Database does not allow binding of any
length data to LOB columns.

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•

A special consideration applies on the maximum size of bind variables that are
neither LONG or LOB, but that appear after any LOB or LONG bind variable in the
SQL statement. You receive an ORA-24816 error from Oracle Database if the
maximum size for such bind variables exceeds 4000 bytes. To avoid this error,
you must set OCI_ATTR_MAXDATA_SIZE to 4000 bytes for any such binds whose
maximum size may exceed 4000 bytes on the server side after character set
conversion. Alternatively, reorder the binds so that such binds are placed before
any LONG or LOBs in the bind list.

•

Oracle Database does not do implicit conversions, such as HEX to RAW or RAW to HEX,
for data of size more than 4000 bytes. The PL/SQL code in the following code
example illustrates this:
Demonstrating Some Implicit Conversions That Cannot Be Done
create table t (c1 clob, c2 blob);
declare
text varchar(32767);
binbuf raw(32767);
begin
text := lpad ('a', 12000, 'a');
binbuf := utl_raw.cast_to_raw(text);
-- The following works:
insert into t values (text, binbuf);
-- The following does not work because Oracle dpes not do implicit
-- hex to raw conversion.
insert into t (c2) values (text);
-- The following does not work because Oracle does not do implicit
-- raw to hex conversion.
insert into t (c1) values (binbuf);
-- The following does not work because you cannot combine the
-- utl_raw.cast_to_raw() operator with the >4k bind.
insert into t (c2) values (utl_raw.cast_to_raw(text));
end;
/

•

If you bind more than 4000 bytes of data to a BLOB or a CLOB, and the data is filtered
by a SQL operator, then Oracle Database limits the size of the result to at most
4000 bytes.
For example:
create table t (c1 clob, c2 blob);
-- The following command inserts only 4000 bytes because the result of
-- LPAD is limited to 4000 bytes
insert into t(c1) values (lpad('a', 5000, 'a'));
-- The following command inserts only 2000 bytes because the result of
-- LPAD is limited to 4000 bytes, and the implicit hex to raw conversion
-- converts it to 2000 bytes of RAW data.
insert into t(c2) values (lpad('a', 5000, 'a'));

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See Also:
About Using the OCI_ATTR_MAXDATA_SIZE Attribute

7.2.1.2.2 Examples of Binding LOB Data
Shows some exampled of binding LOB data.
The following SQL statements are used in Example 7-5 through Example 7-12:
CREATE TABLE foo (a INTEGER );
CREATE TYPE lob_typ AS OBJECT (A1 CLOB );
CREATE TABLE lob_long_tab (C1 CLOB, C2 CLOB, CT3 lob_typ, L LONG);

Example 7-5 Allowed: Inserting into C1, C2, and L Columns Up to 8000, 8000,
and 2000 Byte-Sized Bind Variable Data Values, Respectively
void insert()
/* A function in an OCI program */
{
/* The following is allowed */
ub1 buffer[8000];
text *insert_sql = (text *) "INSERT INTO lob_long_tab (C1, C2, L) \
VALUES (:1, :2, :3)";
OCIStmtPrepare(stmthp, errhp, insert_sql, strlen((char*)insert_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[1], errhp, 2, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[2], errhp, 3, (void *)buffer, 2000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

Example 7-6 Allowed: Inserting into C1 and L Columns up to 2000 and 8000
Byte-Sized Bind Variable Data Values, Respectively
void insert()
{
/* The following is allowed */
ub1 buffer[8000];
text *insert_sql = (text *) "INSERT INTO lob_long_tab (C1, L) \
VALUES (:1, :2)";
OCIStmtPrepare(stmthp, errhp, insert_sql, strlen((char*)insert_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 2000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[1], errhp, 2, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

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Example 7-7 Allowed: Updating C1, C2, and L Columns up to 8000, 8000, and
2000 Byte-Sized Bind Variable Data Values, Respectively
void update()
{
/* The following is allowed, no matter how many rows it updates */
ub1 buffer[8000];
text *update_sql = (text *)"UPDATE lob_long_tab SET \
C1 = :1, C2=:2, L=:3";
OCIStmtPrepare(stmthp, errhp, update_sql, strlen((char*)update_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[1], errhp, 2, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[2], errhp, 3, (void *)buffer, 2000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

Example 7-8 Allowed: Updating C1, C2, and L Columns up to 2000, 2000, and
8000 Byte-Sized Bind Variable Data Values, Respectively
void update()
{
/* The following is allowed, no matter how many rows it updates */
ub1 buffer[8000];
text *update_sql = (text *)"UPDATE lob_long_tab SET \
C1 = :1, C2=:2, L=:3";
OCIStmtPrepare(stmthp, errhp, update_sql, strlen((char*)update_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 2000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[1], errhp, 2, (void *)buffer, 2000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[2], errhp, 3, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

Example 7-9
Operations

Allowed: Piecewise, Callback, and Array Insert or Update

void insert()
{
/* Piecewise, callback and array insert/update operations similar to
* the allowed regular insert/update operations are also allowed */
}

Example 7-10 Not Allowed: Inserting More Than 4000 Bytes into Both LOB and
LONG Columns Using the Same INSERT Statement
void insert()
{
/* The following is NOT allowed because you cannot insert >4000 bytes
* into both LOB and LONG columns */
ub1 buffer[8000];
text *insert_sql = (text *)"INSERT INTO lob_long_tab (C1, L) \
VALUES (:1, :2)";

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OCIStmtPrepare(stmthp, errhp, insert_sql, strlen((char*)insert_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[1], errhp, 2, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

Example 7-11 Allowed: Inserting into the CT3 LOB Column up to 2000 ByteSized Bind Variable Data Values
void insert()
{
/* Insert of data into LOB attributes is allowed */
ub1 buffer[8000];
text *insert_sql = (text *)"INSERT INTO lob_long_tab (CT3) \
VALUES (lob_typ(:1))";
OCIStmtPrepare(stmthp, errhp, insert_sql, strlen((char*)insert_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 2000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

Example 7-12 Not Allowed: Binding Any Length Data to a LOB Column in an
Insert As Select Operation
void insert()
{
/* The following is NOT allowed because you cannot do insert as
* select character data into LOB column */
ub1 buffer[8000];
text *insert_sql = (text *)"INSERT INTO lob_long_tab (C1) SELECT \
:1 from FOO";
OCIStmtPrepare(stmthp, errhp, insert_sql, strlen((char*)insert_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIBindByPos(stmthp, &bindhp[0], errhp, 1, (void *)buffer, 8000,
SQLT_LNG, 0, 0, 0, 0, 0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT);
}

7.2.2 About Binding in OCI_DATA_AT_EXEC Mode
If the mode parameter in a call to OCIBindByName() or OCIBindByName2() or OCIBindByPos()
or OCIBindByPos2() is set to OCI_DATA_AT_EXEC, an additional call to OCIBindDynamic() is
necessary if the application uses the callback method for providing data at run time.
The call to OCIBindDynamic() sets up the callback routines, if necessary, for indicating
the data or piece provided. If the OCI_DATA_AT_EXEC mode is chosen, but the standard
OCI piecewise polling method is used instead of callbacks, the call to OCIBindDynamic()
is not necessary.
When binding RETURN clause variables, an application must use OCI_DATA_AT_EXEC
mode, and it must provide callbacks.

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See Also:
•

Runtime Data Allocation and Piecewise Operations in OCI for more
information about piecewise operations

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindDynamic()

7.2.3 About Binding REF CURSOR Variables
REF CURSORs are bound to a statement handle with a bind data type of SQLT_RSET.

See Also:
PL/SQL REF CURSORs and Nested Tables in OCI

7.3 Overview of Defining in OCI
Query statements return data from the database to your application.
When processing a query, you must define an output variable or an array of output
variables for each item in the select list for retrieving data. The define step creates an
association that determines where returned results are stored, and in what format.
For example, if your program processes the following statement then you would
normally define two output variables: one to receive the value returned from the name
column, and one to receive the value returned from the ssn column:
SELECT name, ssn FROM employees
WHERE empno = :empnum

If you were only interested in retrieving values from the name column, you would not
need to define an output variable for ssn. If the SELECT statement being processed
returns more than a single row for a query, the output variables that you define can be
arrays instead of scalar values.
Depending on the application, the define step can occur before or after an execute
operation. If you know the data types of select-list items at compile time, the define
can occur before the statement is executed. If your application is processing dynamic
SQL statements entered by you at run time or statements that do not have a clearly
defined select list, the application must execute the statement to retrieve describe
information. After the describe information is retrieved, the type information for each
select-list item is available for use in defining output variables.
OCI processes the define call locally on the client side. In addition to indicating the
location of buffers where results should be stored, the define step determines what
data conversions must occur when data is returned to the application.

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Note:
Output buffers must be 2-byte aligned.

The dty parameter of the OCIDefineByPos() or OCIDefineByPos2() call specifies the data
type of the output variable. OCI can perform a wide range of data conversions when
data is fetched into the output variable. For example, internal data in Oracle DATE
format can be automatically converted to a String data type on output.
This section includes the following topic: Steps Used in OCI Defining

See Also:
•

Data Types for more information about data types and conversions

•

About Describing Select-List Items

•

OCIDefineByPos() or OCIDefineByPos2()

7.3.1 Steps Used in OCI Defining
A basic define is done with a position call, OCIDefineByPos() or OCIDefineByPos2().
This step creates an association between a select-list item and an output variable.
Additional define calls may be necessary for certain data types or fetch modes. Once
the define step is complete, the OCI library determines where to put retrieved data.
You can make your define calls again to redefine the output variables without having
to reprepare or reexecute the SQL statement.
Example 7-13 shows a scalar output variable being defined following an execute and
describe operation.

See Also:
•

About Describing Select-List Items for an explanation of the describe
step

•

OCIDefineByPos() or OCIDefineByPos2()

Example 7-13 Defining a Scalar Output Variable Following an Execute and
Describe Operation
SELECT department_name FROM departments WHERE department_id = :dept_input
/* The input placeholder was bound earlier, and the data comes from the
user input below */
printf("Enter employee dept: ");
scanf("%d", &deptno);

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Advanced Define Operations in OCI

/* Execute the statement. If OCIStmtExecute() returns OCI_NO_DATA, meaning that
no data matches the query, then the department number is invalid. */
if ((status = OCIStmtExecute(svchp, stmthp, errhp, 0, 0, (OCISnapshot *) 0,
(OCISnapshot *) 0,
OCI_DEFAULT))
&& (status != OCI_NO_DATA))
{
checkerr(errhp, status);
return OCI_ERROR;
}
if (status == OCI_NO_DATA) {
printf("The dept you entered does not exist.\n");
return 0;
}
/* The next two statements describe the select-list item, dname, and
return its length */
checkerr(errhp, OCIParamGet((void *)stmthp, (ub4) OCI_HTYPE_STMT, errhp, (void
**)&parmdp, (ub4) 1));
checkerr(errhp, OCIAttrGet((void*) parmdp, (ub4) OCI_DTYPE_PARAM,
(void*) &deptlen, (ub4 *) &sizelen, (ub4) OCI_ATTR_DATA_SIZE,
(OCIError *) errhp ));
/* Use the retrieved length of dname to allocate an output buffer, and
then define the output variable. If the define call returns an error,
exit the application */
dept = (text *) malloc((int) deptlen + 1);
if (status = OCIDefineByPos(stmthp, &defnp, errhp,
1, (void *) dept, (sb4) deptlen+1,
SQLT_STR, (void *) 0, (ub2 *) 0,
(ub2 *) 0, OCI_DEFAULT))
{
checkerr(errhp, status);
return OCI_ERROR;
}

7.4 Advanced Define Operations in OCI
This section covers advanced define operations, including multistep defines and
defines of named data types and REFs.
In some cases, the define step requires additional calls than just a call to
OCIDefineByPos() or OCIDefineByPos2(); for example, that define the attributes of an
array fetch, OCIDefineArrayOfStruct(), or a named data type fetch, OCIDefineObject().
For example, to fetch multiple rows with a column of named data types, all the three
calls must be invoked for the column. To fetch multiple rows of scalar columns only,
OCIDefineArrayOfStruct() and OCIDefineByPos() or OCIDefineByPos2() are sufficient.
Oracle Database also provides predefined C data types that map object type
attributes.
This section includes the following topics:
•

About Defining LOB Output Variables

•

About Defining PL/SQL Output Variables

•

About Defining for a Piecewise Fetch

7-19

Chapter 7

Advanced Define Operations in OCI

See Also:
•

Object-Relational Data Types in OCI

•

Advanced Define Operations in OCI

•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIDefineArrayOfStruct()

•

OCIDefineObject()

7.4.1 About Defining LOB Output Variables
There are two ways of defining LOBs:
•

Define a LOB locator, rather than the actual LOB values. In this case, the LOB
value is written or read by passing a LOB locator to the OCI LOB functions.

•

Define a LOB value directly, without using the LOB locator.

This section includes the following topics:
•

About Defining LOB Locators

•

About Defining LOB Data

7.4.1.1 About Defining LOB Locators
Either a single locator or an array of locators can be defined in a single define call. In
each case, the application must pass the address of a LOB locator and not the locator
itself. For example, suppose that an application has prepared the following SQL
statement:
SELECT lob1 FROM some_table;

In this statement, lob1 is the LOB column, and one_lob is a define variable
corresponding to a LOB column with the following declaration:
OCILobLocator * one_lob;

Then the following calls would be used to bind the placeholder and execute the
statement:
/* initialize single locator */
OCIDescriptorAlloc(...&one_lob, OCI_DTYPE_LOB...);
...
/* pass the address of the locator */
OCIBindByName(...,(void *) &one_lob,... SQLT_CLOB, ...);
OCIStmtExecute(...,1,...);
/* 1 is the iters parameter */

You can also insert an array using this same SQL SELECT statement. In this case, the
application would include the following code:
OCILobLocator * lob_array[10];
...
for (i=0; i<10, i++)
OCIDescriptorAlloc(...&lob_array[i], OCI_DTYPE_LOB...);
/* initialize array of locators */

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Chapter 7

Advanced Define Operations in OCI

...
OCIBindByName(...,(void *) lob_array,...);
OCIStmtExecute(...,10,...);
/* 10 is the iters parameter */

Note that you must allocate descriptors with the OCIDescriptorAlloc() function before
they can be used. In an array of locators, you must initialize each array element using
OCIDescriptorAlloc(). Use OCI_DTYPE_LOB as the type parameter when allocating BLOBs,
CLOBs, and NCLOBs. Use OCI_DTYPE_FILE when allocating BFILEs.

7.4.1.2 About Defining LOB Data
Oracle Database allows nonzero defines for SELECTs of any size LOB. So you can
select up to the maximum allowed size of data from a LOB column using
OCIDefineByPos() and PL/SQL defines. Because there can be multiple LOBs in a row,
you can select the maximum size of data from each one of those LOBs in the same
SELECT statement.
The following SQL statement is the basis for Example 7-14 and Example 7-15:
CREATE TABLE lob_tab (C1 CLOB, C2 CLOB);

Example 7-14

Defining LOBs Before Execution

void select_define_before_execute()
/* A function in an OCI program */
{
/* The following is allowed */
ub1 buffer1[8000];
ub1 buffer2[8000];
text *select_sql = (text *)"SELECT c1, c2 FROM lob_tab";
OCIStmtPrepare(stmthp, errhp, select_sql, (ub4)strlen((char*)select_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIDefineByPos(stmthp, &defhp[0], errhp, 1, (void *)buffer1, 8000,
SQLT_LNG, (void *)0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT);
OCIDefineByPos(stmthp, &defhp[1], errhp, 2, (void *)buffer2, 8000,
SQLT_LNG, (void *)0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, (OCISnapshot *)0,
(OCISnapshot *)0, OCI_DEFAULT);
}

Example 7-15

Defining LOBs After Execution

void select_execute_before_define()
{
/* The following is allowed */
ub1 buffer1[8000];
ub1 buffer2[8000];
text *select_sql = (text *)"SELECT c1, c2 FROM lob_tab";
OCIStmtPrepare(stmthp, errhp, select_sql, (ub4)strlen((char*)select_sql),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 0, 0, (OCISnapshot *)0,
(OCISnapshot *)0, OCI_DEFAULT);
OCIDefineByPos(stmthp, &defhp[0], errhp, 1, (void *)buffer1, 8000,
SQLT_LNG, (void *)0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT);
OCIDefineByPos(stmthp, &defhp[1], errhp, 2, (void *)buffer2, 8000,
SQLT_LNG, (void *)0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT);
OCIStmtFetch(stmthp, errhp, 1, OCI_FETCH_NEXT, OCI_DEFAULT);
}

7-21

Chapter 7

About Binding and Defining Arrays of Structures in OCI

7.4.2 About Defining PL/SQL Output Variables
Do not use the define calls to define output variables for select-list items in a SQL
SELECT statement inside a PL/SQL block.
Use OCI bind calls instead.

See Also:
Information for Named Data Type and REF Defines, and PL/SQL OUT Binds
for more information about defining PL/SQL output variables

7.4.3 About Defining for a Piecewise Fetch
A piecewise fetch requires an initial call to OCIDefineByPos() or OCIDefineByPos2().
An additional call to OCIDefineDynamic() is necessary if the application uses callbacks
rather than the standard polling mechanism.

See Also:
•

OCIDefineByPos()or OCIDefineByPos2()

•

OCIDefineDynamic()

7.5 About Binding and Defining Arrays of Structures in OCI
Defining arrays of structures requires an initial call to OCIDefineByPos() or
OCIDefineByPos2().
An additional call to OCIDefineArrayOfStruct() is necessary to set up each additional
parameter, including the skip parameter necessary for arrays of structures operations.
Using arrays of structures can simplify the processing of multirow, multicolumn
operations. You can create a structure of related scalar data items, and then fetch
values from the database into an array of these structures, or insert values into the
database from an array of these structures.
For example, an application may need to fetch multiple rows of data from columns
NAME, AGE, and SALARY. The application can include the definition of a structure
containing separate fields to hold the NAME, AGE, and SALARY data from one row in the
database table. The application would then fetch data into an array of these structures.
To perform a multirow, multicolumn operation using an array of structures, associate
each column involved in the operation with a field in a structure. This association,
which is part of OCIDefineArrayOfStruct() and OCIBindArrayOfStruct() calls, specifies
where data is stored.
This section includes the following topics:

7-22

Chapter 7

About Binding and Defining Arrays of Structures in OCI

•

Skip Parameters

•

OCI Calls Used with Arrays of Structures

•

Arrays of Structures and Indicator Variables

See Also:
•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIDefineArrayOfStruct()

•

OCIBindArrayOfStruct()

7.5.1 Skip Parameters
When you split column data across an array of structures, it is no longer stored
contiguously in the database.
The single array of structures stores data as though it were composed of several
arrays of scalars. For this reason, you must specify a skip parameter for each field that
you are binding or defining. This skip parameter is the number of bytes that must be
skipped in the array of structures before the same field is encountered again. In
general, this is equivalent to the byte size of one structure.
Figure 7-2 shows how a skip parameter is determined. In this case, the skip parameter
is the sum of the sizes of the fields field1 (2 bytes), field2 (4 bytes), and field3 (2
bytes), which is 8 bytes. This equals the size of one structure.

Figure 7-2

Determining Skip Parameters

Array of Structures

field 2
4 bytes

field 3 field 1
2 bytes 2 bytes

skip 8 bytes

field 2
4 bytes

field 3 field 1
2 bytes 2 bytes

field 2
4 bytes

field 3
2 bytes

.
..
..

field 1
2 bytes

skip 8 bytes

On some operating systems it may be necessary to set the skip parameter to
sizeof(one_array_element) rather than sizeof(struct), because some compilers insert
extra bytes into a structure.
Consider an array of C structures consisting of two fields, a ub4 and a ub1:
struct demo {
ub4 field1;
ub1 field2;
};
struct demo demo_array[MAXSIZE];

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Chapter 7

About Binding and Defining Arrays of Structures in OCI

Some compilers insert 3 bytes of padding after the ub1 so that the ub4 that begins the
next structure in the array is properly aligned. In this case, the following statement may
return an incorrect value:
skip_parameter = sizeof(struct demo);

On some operating systems this produces a proper skip parameter of 8. On other
systems, skip_parameter is set to 5 bytes by this statement. In the latter case, use the
following statement to get the correct value for the skip parameter:
skip_parameter = sizeof(demo_array[0]);

This section includes the following topic: Skip Parameters for Standard Arrays.

7.5.1.1 Skip Parameters for Standard Arrays
Arrays of structures are an extension of binding and defining arrays of single variables.
When you specify a single-variable array operation, the related skip equals the size of
the data type of the array under consideration. For example, consider an array
declared as follows:
text emp_names[4][20];

The skip parameter for the bind or define operation is 20. Each data element in the
array is then recognized as a separate unit, rather than being part of a structure.

7.5.2 OCI Calls Used with Arrays of Structures
What calls must be used when you perform operations involving arrays of structures.
Two OCI calls must be used when you perform operations involving arrays of
structures:
•

Use OCIBindArrayOfStruct() for binding fields in arrays of structures for input
variables

•

Use OCIDefineArrayOfStruct() for defining arrays of structures for output variables.

Note:
Binding or defining for arrays of structures requires multiple calls. A call
to OCIBindByName() or OCIBindByName2() or OCIBindByPos() or
OCIBindByPos2() must precede a call to OCIBindArrayOfStruct(), and a
call to OCIDefineByPos() or OCIDefineByPos2() must precede a call to
OCIDefineArrayOfStruct().

7-24

Chapter 7

About Binding and Defining Multiple Buffers

See Also:
•

OCIBindArrayOfStruct()

•

OCIDefineArrayOfStruct()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIDefineByPos()or OCIDefineByPos2()

7.5.3 Arrays of Structures and Indicator Variables
The implementation of arrays of structures in addition supports the use of indicator
variables and return codes.
You can declare parallel arrays of column-level indicator variables and return codes
that correspond to the arrays of information being fetched, inserted, or updated. These
arrays can have their own skip parameters, which are specified during
OCIBindArrayOfStruct() or OCIDefineArrayOfStruct() calls.
You can set up arrays of structures of program values and indicator variables in many
ways. Consider an application that fetches data from three database columns into an
array of structures containing three fields. You can set up a corresponding array of
indicator variable structures of three fields, each of which is a column-level indicator
variable for one of the columns being fetched from the database. A one-to-one
relationship between the fields in an indicator struct and the number of select-list items
is not necessary.

See Also:
•

Indicator Variables

•

OCIBindArrayOfStruct()

•

OCIDefineArrayOfStruct()

7.6 About Binding and Defining Multiple Buffers
You can specify multiple buffers for use with a single bind or define call.
Performance is improved because the number of round-trips is decreased when data
stored at different noncontiguous addresses is not copied to one contiguous location.
CPU time spent and memory used are thus reduced.
The data type OCIIOV is defined as:
typedef struct OCIIOV
{
void *bfp; /* The pointer to a buffer for the data

*/

7-25

Chapter 7

About Binding and Defining Multiple Buffers

ub4 bfl;
}OCIIOV;

/* The size of the buffer

*/

The value OCI_IOV for the mode parameter is used in the OCIBindByPos() or
OCIBindByPos2() and OCIBindByName() or OCIBindByName2() functions for binding multiple
buffers. If this value of mode is specified, the address of OCIIOV must be passed in
parameter valuep. The size of the data type must be passed in the parameter valuesz.
For example:
OCIIOV vecarr[NumBuffers];
...
/* For bind at position 1 with data type int
*/
OCIBindByPos(stmthp, bindp, errhp, 1, (void *)&vecarr[0],
sizeof(int), ... OCI_IOV);
...

The value OCI_IOV for the mode parameter is used in the OCIDefineByPos() or
OCIDefineByPos2() function for defining multiple buffers. If this value of mode is specified,
the address of OCIIOV is passed in parameter valuep. The size of the data type must be
passed in the parameter valuesz. This mode is intended to be used for scatter or
gather binding, which allows multiple buffers to be bound or defined to a position, for
example column A for the first 10 rows in one buffer, next 5 rows in one buffer, and the
remaining 25 rows in another buffer. That eliminates the need to allocate and copy all
of them into one big buffer while doing the array execute operation.
Example 7-16 illustrates the use of the structure OCIIOV and its mode values.
Example 7-16

Using Multiple Bind and Define Buffers

/* The following macros mention the maximum length of the data in the
* different buffers. */
#define
#define

/* These
array
#define
#define

LENGTH_DATE
10
LENGTH_EMP_NAME 100

two macros represent the number of elements in each bind and define
*/
NUM_BIND
30
NUM_DEFINE 45

/* The bind buffers for inserting dates */
char buf_1[NUM_BIND][LENGTH_DATE],
char buf_2[NUM_BIND * 2][LENGTH_DATE],
/* The bind buffer for inserting emp name */
char buf_3[NUM_BIND * 3][LENGTH_EMP_NAME],
/* The define buffers */
char buf_4[NUM_DEFINE][LENGTH_EMP_NAME];
char buf_5[NUM_DEFINE][LENGTH_EMP_NAME];
/* The size of data value for buffers corresponding to the same column must be
the same, and that value is passed in the OCIBind or Define calls.
buf_4 and buf_5 above have the same data values; that is, LENGTH_EMP_NAME
although the number of elements are different in the two buffers.
*/
OCIBind
OCIBind

*bndhp1 = (OCIBind
*bndhp2 = (OCIBind

*)0;
*)0;

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Chapter 7

About Binding and Defining Multiple Buffers

OCIDefine
OCIStmt
OCIError

*defhp = (OCIDefine *)0;
*stmthp = (OCIStmt *)0;
*errhp = (OCIError *)0;

OCIIOV bvec[2], dvec[2];
/*
Example of how to use indicators and return codes with this feature,
showing the allocation when using with define. You allocate memory
for indicator, return code, and the length buffer as one chunk of
NUM_DEFINE * 2 elements.
*/
short *indname[NUM_DEFINE*2];
/* indicators */
ub4 *alenname[NUM_DEFINE*2];
/* return lengths */
ub2 *rcodename[NUM_DEFINE*2];
/* return codes */
static text *insertstr =
"INSERT INTO EMP (EMP_NAME, JOIN_DATE) VALUES (:1, :2)";
static text *selectstr = "SELECT EMP_NAME FROM EMP";
/* Allocate environment, error handles, and so on, and then initialize the
environment. */
...
/* Prepare the statement with the insert query in order to show the
binds. */
OCIStmtPrepare (stmthp, errhp, insertstr,
(ub4)strlen((char *)insertstr),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
/*
*
*
*

Populate buffers with values. The following represents the simplest
way of populating the buffers. However, in an actual scenario
these buffers may have been populated by data received from different
sources. */

/* Store the date in the bind buffers for the date. */
strcpy(buf_1[0], "21-SEP-02");
...
strcpy(buf_1[NUM_BIND - 1], "21-OCT-02");
...
strcpy(buf_2[0], "22-OCT-02");
...
strcpy(buf_2[2*NUM_BIND - 1], "21-DEC-02");
...
memset(bvec[0], 0, sizeof(OCIIOV));
memset(bvec[1], 0, sizeof(OCIIOV));
/* Set up the addresses in the IO Vector structure */
bvec[0].bfp = buf_1[0];
/* Buffer address of the data */
bvec[0].bfl = NUM_BIND*LENGTH_DATE;
/* Size of the buffer */
/* And so on for other structures as well. */
bvec[1].bfp = buf_2[0];
/* Buffer address of the data */
bvec[1].bfl = NUM_BIND*2*LENGTH_DATE;
/* Size of the buffer */
/* Do the bind for date, using OCIIOV */
OCIBindByPos (stmthp, &bindhp2, errhp, 2, (void *)&bvec[0],
sizeof(buf_1[0]), SQLT_STR,
(void *)inddate, (ub2 *)alendate, (ub2 *)rcodedate, 0,
(ub4 *)0, OCI_IOV);
/* Store the employee names in the bind buffers, 3 for the names */

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Chapter 7

About Binding and Defining Multiple Buffers

strcpy (buf_3[0], "JOHN ");
...
strcpy (buf_3[NUM_BIND *3 - 1], "HARRY");
/* Do the bind for employee name */
OCIBindByPos (stmthp, &bindhp1, errhp, 1, buf_3[0], sizeof(buf_3[0]),
SQLT_STR, (void *)indemp, (ub2 *)alenemp, (ub2 *)rcodeemp, 0,
(ub4 *)0, OCI_DEFAULT);
OCIStmtExecute (svchp, stmthp, errhp, NUM_BIND*3, 0,
(OCISnapshot *)0, (OCISnapshot *)0, OCI_DEFAULT);
...
/* Now the statement to depict defines */
/* Prepare the statement with the select query in order to show the
defines */
OCIStmtPrepare(stmthp, errhp, selectstr,(ub4)strlen((char *)selectstr),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
memset(dvec[0], 0, sizeof(OCIIOV);
memset(dvec[1], 0, sizeof(OCIIOV));
/* Set up the define vector */
dvec[0].bfp = buf_4[0];
dvec[0].bfl = NUM_DEFINE*LENGTH_EMP_NAME;
dvec[1].bfp = buf_5[0];
dvec[1].bfl = NUM_DEFINE*LENGTH_EMP_NAME;
/*
Pass the buffers for the indicator, length of the data, and the
return code. Note that the buffer where you receive
the data is split into two locations,
each having NUM_DEFINE number of elements. However, the indicator
buffer, the actual length buffer, and the return code buffer comprise a
single chunk of NUM_DEFINE * 2 elements.
*/
OCIDefineByPos (stmthp, &defhp, errhp, 1, (void *)&dvec[0],
sizeof(buf_4[0]), SQLT_STR, (void *)indname,
(ub2 *)alenname, (ub2 *)rcodename, OCI_IOV);
OCIStmtExecute (svchp, stmthp, errhp, NUM_DEFINE*2, 0,
(OCISnapshot*)0,
(OCISnapshot*)0, OCI_DEFAULT);
...

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIDefineByPos() or OCIDefineByPos2()

7-28

Chapter 7

DML with a RETURNING Clause in OCI

7.7 DML with a RETURNING Clause in OCI
This section outlines the rules for correctly implementing DML statements with the
RETURNING clause.

OCI supports the use of the RETURNING clause with SQL INSERT, UPDATE, and DELETE
statements.
This section includes the following topics:
•

About Using DML with a RETURNING Clause to Combine Two SQL Statements

•

About Binding RETURNING...INTO Variables

•

OCI Error Handling

•

DML with RETURNING REF...INTO Clause in OCI

•

Additional Notes About OCI Callbacks

•

Array Interface for DML RETURNING Statements in OCI

See Also:
•

The Database demonstration programs included with your Oracle
installation for complete examples. For additional information, see OCI
Demonstration Programs.

•

Oracle Database SQL Language Reference for more information about
the use of the RETURNING clause with INSERT, UPDATE, or DELETE statements

7.7.1 About Using DML with a RETURNING Clause to Combine Two
SQL Statements
Using the RETURNING clause with a DML statement enables you to combine two SQL
statements into one, possibly saving a server round-trip.
This is accomplished by adding an extra clause to the traditional UPDATE, INSERT, and
DELETE statements. The extra clause effectively adds a query to the DML statement.
In OCI, values are returned to the application as OUT bind variables. In the following
examples, the bind variables are indicated by a preceding colon, ":". These examples
assume the existence of table1, a table that contains columns col1, col2, and col3.
The following statement inserts new values into the database and then retrieves the
column values of the affected row from the database, for manipulating inserted rows.
INSERT INTO table1 VALUES (:1, :2, :3)
RETURNING col1, col2, col3
INTO :out1, :out2, :out3

The next example updates the values of all columns where the value of col1 falls
within a given range, and then returns the affected rows that were modified.

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UPDATE table1 SET col1 = col1 + :1, col2 = :2, col3 = :3
WHERE col1 >= :low AND col1 <= :high
RETURNING col1, col2, col3
INTO :out1, :out2, :out3

The DELETE statement deletes the rows where col1 value falls within a given range, and
then returns the data from those rows.
DELETE FROM table1 WHERE col1 >= :low AND col2 <= :high
RETURNING col1, col2, col3
INTO :out1, :out2, :out3

7.7.2 About Binding RETURNING...INTO Variables
Because both the UPDATE and DELETE statements can affect multiple rows in the table,
and a DML statement can be executed multiple times in a single OCIStmtExecute() call,
how much data is returned may not be known at run time.
As a result, the variables corresponding to the RETURNING...INTO placeholders must be
bound in OCI_DATA_AT_EXEC mode. An application must define its own dynamic data
handling callbacks rather than using a polling mechanism.
The returning clause can be particularly useful when working with LOBs. Normally, an
application must insert an empty LOB locator into the database, and then select it back
out again to operate on it. By using the RETURNING clause, the application can combine
these two steps into a single statement:
INSERT INTO some_table VALUES (:in_locator)
RETURNING lob_column
INTO :out_locator

An OCI application implements the placeholders in the RETURNING clause as pure OUT
bind variables. However, all binds in the RETURNING clause are initially IN and must be
properly initialized. To provide a valid value, you can provide a NULL indicator and set
that indicator to -1.
An application must adhere to the following rules when working with bind variables in a
RETURNING clause:

•

Bind RETURNING clause placeholders in OCI_DATA_AT_EXEC mode using
OCIBindByName() or OCIBindByName2() or OCIBindByPos() or OCIBindByPos2(), followed
by a call to OCIBindDynamic() for each placeholder.

•

When binding RETURNING clause placeholders, supply a valid OUT bind function as
the ocbfp parameter of the OCIBindDynamic() call. This function must provide
storage to hold the returned data.

•

The icbfp parameter of OCIBindDynamic() call should provide a default function that
returns NULL values when called.

•

The piecep parameter of OCIBindDynamic() must be set to OCI_ONE_PIECE.

No duplicate binds are allowed in a DML statement with a RETURNING clause, and no
duplication is allowed between bind variables in the DML section and the RETURNING
section of the statement.

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Chapter 7

DML with a RETURNING Clause in OCI

Note:
OCI supports only the callback mechanism for RETURNING clause binds. The
polling mechanism is not supported.

See Also:
•

OCIStmtExecute()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindDynamic()

7.7.3 OCI Error Handling
The OUT bind function provided to OCIBindDynamic() must be prepared to receive partial
results of a statement if there is an error.
If the application has issued a DML statement that is executed 10 times, and an error
occurs during the fifth iteration, the Oracle database returns the data from iterations 1
through 4. The callback function is still called to receive data for the first four iterations.

7.7.4 DML with RETURNING REF...INTO Clause in OCI
The RETURNING clause can also be used to return a REF to an object that is being
inserted into or updated in the database.
UPDATE extaddr e SET e.zip = '12345', e.state ='AZ'
WHERE e.state = 'CA' AND e.zip = '95117'
RETURNING REF(e), zip
INTO :addref, :zip

The preceding statement updates several attributes of an object in an object table and
returns a REF to the object (and a scalar postal code (ZIP)) in the RETURNING clause.
This section includes the following topic: Binding the Output Variable.

7.7.4.1 Binding the Output Variable
Binding the REF output variable in an OCI application requires three steps.
The following pseudocode in Example 7-17 shows a function that performs the binds
necessary for the preceding three steps.
1.

Set the initial bind information is set using OCIBindByName() or OCIBindByName2().

2.

Set additional bind information for the REF, including the type description object
(TDO), is set with OCIBindObject().

3.

Make a call is made to OCIBindDynamic().

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Example 7-17

Binding the REF Output Variable in an OCI Application

sword bind_output(stmthp, bndhp, errhp)
OCIStmt *stmthp;
OCIBind *bndhp[];
OCIError *errhp;
{
ub4 i;
/* get TDO for BindObject call */
if (OCITypeByName(envhp, errhp, svchp, (CONST text *) 0,
(ub4) 0, (CONST text *) "ADDRESS_OBJECT",
(ub4) strlen((CONST char *) "ADDRESS_OBJECT"),
(CONST text *) 0, (ub4) 0,
OCI_DURATION_SESSION, OCI_TYPEGET_HEADER, &addrtdo))
{
return OCI_ERROR;
}
/* initial bind call for both variables */
if (OCIBindByName(stmthp, &bndhp[2], errhp,
(text *) ":addref", (sb4) strlen((char *) ":addref"),
(void *) 0, (sb4) sizeof(OCIRef *), SQLT_REF,
(void *) 0, (ub2 *)0, (ub2 *)0,
(ub4) 0, (ub4 *) 0, (ub4) OCI_DATA_AT_EXEC)
|| OCIBindByName(stmthp, &bndhp[3], errhp,
(text *) ":zip", (sb4) strlen((char *) ":zip"),
(void *) 0, (sb4) MAXZIPLEN, SQLT_CHR,
(void *) 0, (ub2 *)0, (ub2 *)0,
(ub4) 0, (ub4 *) 0, (ub4) OCI_DATA_AT_EXEC))
{
return OCI_ERROR;
}
/* object bind for REF variable */
if (OCIBindObject(bndhp[2], errhp, (OCIType *) addrtdo,
(void **) &addrref[0], (ub4 *) 0, (void **) 0, (ub4 *) 0))
{
return OCI_ERROR;
}

for (i = 0; i < MAXCOLS; i++)
pos[i] = i;
/* dynamic binds for both RETURNING variables */
if (OCIBindDynamic(bndhp[2], errhp, (void *) &pos[0], cbf_no_data,
(void *) &pos[0], cbf_get_data)
|| OCIBindDynamic(bndhp[3], errhp, (void *) &pos[1], cbf_no_data,
(void *) &pos[1], cbf_get_data))
{
return OCI_ERROR;
}
return OCI_SUCCESS;
}

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See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindObject()

•

OCIBindDynamic()

7.7.5 Additional Notes About OCI Callbacks
When a callback function is called, the OCI_ATTR_ROWS_RETURNED attribute of the bind
handle tells the application the number of rows being returned in that particular
iteration.
During the first callback of an iteration, you can allocate space for all rows that are
returned for that bind variable. During subsequent callbacks of the same iteration, you
increment the buffer pointer to the correct memory within the allocated space.

7.7.6 Array Interface for DML RETURNING Statements in OCI
OCI provides additional functionality for single-row DML and array DML operations in
which each iteration returns more than one row.
To take advantage of this feature, you must specify an OUT buffer in the bind call that
is at least as big as the iteration count specified by the OCIStmtExecute() call. This is in
addition to the bind buffers provided through callbacks.
If any of the iterations returns more than one row, then the application receives an
OCI_SUCCESS_WITH_INFO return code. In this case, the DML operation is successful. At
this point, the application may choose to roll back the transaction or ignore the
warning.

See Also:
OCIStmtExecute()

7.8 Character Conversion in OCI Binding and Defining
This section discusses issues involving character conversions between the client and
the server.
This section includes the following topics:
•

About Choosing a Character Set

•

About Setting Client Character Sets in OCI

•

About Binding Variables in OCI

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7.8.1 About Choosing a Character Set
If a database column containing character data is defined to be a CHAR or VARCHAR2 or
NCHAR or NVARCHAR2 column, then a bind or define involving that column must make
special considerations for dealing with character set specifications.
These considerations are necessary in case the width of the client character set is
different from the server character set, and also for proper character conversion.
During conversion of data between different character sets, the size of the data may
increase or decrease by up to a factor of four. Ensure that buffers that are provided to
hold the data are of sufficient size.
Beginning with Oracle Database 12c Release 2 (12.2), OCI provides two service
context handle attributes OCI_ATTR_MAX_CHARSET_RATIO and OCI_ATTR_MAX_NCHARSET_RATIO
to obtain the maximum character set expansion ratio from server to client character set
or national character set respectively. Using these attributes lets you more efficiently
allocate optimal memory of buffers before conversion so that when data is returned
from the database, sufficient space can be allocated to hold it. Using these attributes is
useful in scenarios where there are different character sets or national character sets
between server and client.
The following code example shows how get the maximum character set expansion
ratio from server to client character set:
size_t cratio;
OCIAttrGet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX, (size_t *)&cratio, (ub4) 0,
OCI_ATTR_MAX_CHARSET_RATIO, errhp);
printf("Conversion ratio from server to client character set is %d\n", cratio);
Conversion ratio from server to client character set is 2

The following code example shows how get the maximum character set expansion
ratio from server to client national character set:
size_t cratio;
OCIAttrGet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX, (size_t *)&cratio, (ub4) 0,
OCI_ATTR_MAX_NCHARSET_RATIO, errhp);
printf("Conversion ratio from server to client ncharset is %d\n", cratio);
Conversion ratio from server to client ncharset is 1

In some cases, it may also be easier for an application to deal with CHAR or VARCHAR2 or
with NCHAR or NVARCHAR2 data in terms of numbers of characters, rather than numbers of
bytes, which is the usual case.
This section includes the following topics:
•

Character Set Form and ID

•

Implicit Conversion Between CHAR and NCHAR

7.8.1.1 Character Set Form and ID
Each OCI bind and define handle is associated with the OCI_ATTR_CHARSET_FORM and
OCI_ATTR_CHARSET_ID attributes.

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An application can set these attributes with the OCIAttrSet() call to specify the
character form and character set ID of the bind or define buffer.
The csform attribute (OCI_ATTR_CHARSET_FORM) indicates the character set of the client
buffer for binds, and the character set in which to store fetched data for defines. It has
two possible values:
•

SQLCS_IMPLICIT - Default value indicates that the database character set ID for the

bind or define buffer and the character buffer data are converted to the server
database character set
•

SQLCS_NCHAR - Indicates that the national character set ID for the bind or define

buffer and the client buffer data are converted to the server national character set.
If the character set ID attribute, OCI_ATTR_CHARSET_ID, is not specified, either the default
value of the database or the national character set ID of the client is used, depending
on the value of csform. They are the values specified in the NLS_LANG and NLS_NCHAR
environment variables, respectively.

Note:
•

The data is converted and inserted into the database according to the
server's database character set ID or national character set ID,
regardless of the client-side character set ID.

•

OCI_ATTR_CHARSET_ID must never be set to 0.

•

The define handle attributes OCI_ATTR_CHARSET_FORM and
OCI_ATTR_CHARSET_ID do not affect the LOB types. LOB locators fetched
from the server retain their original csforms. There is no CLOB/NCLOB
conversion as part of define conversion based on these attributes.

See Also:
•

Oracle Database SQL Language Reference for more information about
NCHAR data

•

OCIAttrSet()

7.8.1.2 Implicit Conversion Between CHAR and NCHAR
As the result of implicit conversion between database character sets and national
character sets, OCI can support cross binding and cross defining between CHAR and
NCHAR.
Although the OCI_ATTR_CHARSET_FORM attribute is set to SQLCS_NCHAR, OCI enables
conversion of data to the database character set if the data is inserted into a CHAR
column.

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7.8.2 About Setting Client Character Sets in OCI
You can set the client character sets through the OCIEnvNlsCreate() function
parameters charset and ncharset.
Both of these parameters can be set as OCI_UTF16ID. The charset parameter controls
coding of the metadata and CHAR data. The ncharset parameter controls coding of NCHAR
data. The function OCINlsEnvironmentVariableGet() returns the character set from
NLS_LANG and the national character set from NLS_NCHAR.
Example 7-18 illustrates the use of these functions (OCI provides a typedef called
utext to facilitate binding and defining of UTF-16 data):

See Also:
•

OCIEnvNlsCreate()

•

OCINlsEnvironmentVariableGet()

Example 7-18

Setting the Client Character Set to OCI_UTF16ID in OCI

OCIEnv *envhp;
ub2 ncsid = 2; /* we8dec */
ub2 hdlcsid, hdlncsid;
OraText thename[20];
utext *selstmt = L"SELECT ename FROM emp"; /* UTF16 statement */
OCIStmt *stmthp;
OCIDefine *defhp;
OCIError *errhp;
OCIEnvNlsCreate(OCIEnv **envhp, ..., OCI_UTF16ID, ncsid);
...
OCIStmtPrepare(stmthp, ..., selstmt, ...); /* prepare UTF16 statement */
OCIDefineByPos(stmthp, defnp, ..., 1, thename, sizeof(thename), SQLT_CHR,...);
OCINlsEnvironmentVariableGet(&hdlcsid, (size_t)0, OCI_NLS_CHARSET_ID, (ub2)0,
(size_t*)NULL);
OCIAttrSet(defnp, ..., &hdlcsid, 0, OCI_ATTR_CHARSET_ID, errhp);
/* change charset ID to NLS_LANG setting*/
...

7.8.3 About Binding Variables in OCI
Update or insert operations are done through variable binding.
When binding variables, specify the OCI_ATTR_MAXDATA_SIZE attribute and
OCI_ATTR_MAXCHAR_SIZE attribute in the bind handle to indicate the byte and character
constraints used when inserting data in to the Oracle database.
These attributes are defined as:
•

The OCI_ATTR_MAXDATA_SIZE attribute sets the maximum number of bytes allowed in
the buffer on the server side.

•

The OCI_ATTR_MAXCHAR_SIZE attribute sets the maximum number of characters
allowed in the buffer on the server side.

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This section includes these additional topics:
•

Buffer Expansion During OCI Binding

•

Constraint Checking During Defining

•

General Compatibility Issues for Character-Length Semantics in OCI

See Also:
•

About Using the OCI_ATTR_MAXDATA_SIZE Attribute for more
information

•

About Using the OCI_ATTR_MAXCHAR_SIZE Attribute for more
information

7.8.3.1 About Using the OCI_ATTR_MAXDATA_SIZE Attribute
Every bind handle has an OCI_ATTR_MAXDATA_SIZE attribute that specifies the number of
bytes allocated on the server to accommodate client-side bind data after character set
conversions.
An application typically sets OCI_ATTR_MAXDATA_SIZE to the maximum size of the column
or the size of the PL/SQL variable, depending on how it is used. Oracle Database
issues an error if OCI_ATTR_MAXDATA_SIZE is not large enough to accommodate the data
after conversion, and the operation fails.
For IN/INOUT binds, when OCI_ATTR_MAXDATA_SIZE attribute is set, the bind buffer must
be large enough to hold the number of characters multiplied by the bytes in each
character of the character set.
If OCI_ATTR_MAXCHAR_SIZE is set to a nonzero value such as 100, then if the character set
has 2 bytes in each character, the minimum possible allocated size is 200 bytes.
The following scenarios demonstrate some uses of the OCI_ATTR_MAXDATA_SIZE attribute:
•

Scenario 1: CHAR (source data) converted to non-CHAR (destination column)
There are implicit bind conversions of the data. The recommended value of
OCI_ATTR_MAXDATA_SIZE is the size of the source buffer multiplied by the worst-case
expansion factor between the client and Oracle Database character sets.

•

Scenario 2: CHAR (source data) converted to CHAR (destination column) or non-CHAR
(source data) converted to CHAR (destination column)
The recommended value of OCI_ATTR_MAXDATA_SIZE is the size of the column.

•

Scenario 3: CHAR (source data) converted to a PL/SQL variable
In this case, the recommended value of OCI_ATTR_MAXDATA_SIZE is the size of the
PL/SQL variable.

7.8.3.2 About Using the OCI_ATTR_MAXCHAR_SIZE Attribute
OCI_ATTR_MAXCHAR_SIZE enables processing to work with data in terms of number of
characters, rather than number of bytes.

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For binds, the OCI_ATTR_MAXCHAR_SIZE attribute sets the number of characters reserved
in the Oracle database to store the bind data.
For example, if OCI_ATTR_MAXDATA_SIZE is set to 100, and OCI_ATTR_MAXCHAR_SIZE
is set to 0, then the maximum possible size of the data in the Oracle database after
conversion is 100 bytes. However, if OCI_ATTR_MAXDATA_SIZE is set to 300, and
OCI_ATTR_MAXCHAR_SIZE is set to a nonzero value, such as 100, then if the character set
has 2 bytes/character, the maximum possible allocated size is 200 bytes.
For defines, the OCI_ATTR_MAXCHAR_SIZE attribute specifies the maximum number of
characters that the client application allows in the return buffer. Its derived byte length
overrides the maxlength parameter specified in the OCIDefineByPos() or
OCIDefineByPos2() call.

Note:
Regardless of the value of the attribute OCI_ATTR_MAXCHAR_SIZE, the buffer
lengths specified in a bind or define call are always in terms of bytes. The
actual length values sent and received by you are also in bytes.

See Also:
OCIDefineByPos() or OCIDefineByPos2()

7.8.3.3 Buffer Expansion During OCI Binding
Do not set OCI_ATTR_MAXDATA_SIZE for OUT binds or for PL/SQL binds. Only set
OCI_ATTR_MAXDATA_SIZE for INSERT or UPDATE statements.
If neither of these two attributes is set, OCI expands the buffer using its best
estimates.
This section includes the following topics:
•

IN Binds

•

Dynamic SQL

•

Buffer Expansion During Inserts

7.8.3.3.1 IN Binds
For an IN bind, if the underlying column was created using character-length semantics,
then it is preferable to specify the constraint using OCI_ATTR_MAXCHAR_SIZE.
As long as the actual buffer contains fewer characters than specified in
OCI_ATTR_MAXCHAR_SIZE, no constraints are violated at OCI level.

If the underlying column was created using byte-length semantics, then use
OCI_ATTR_MAXDATA_SIZE in the bind handle to specify the byte constraint on the server. If
you also specify an OCI_ATTR_MAXCHAR_SIZE value, then this constraint is imposed when
allocating the receiving buffer on the server side.

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7.8.3.3.2 Dynamic SQL
For dynamic SQL, you can use the explicit describe to get OCI_ATTR_DATA_SIZE and
OCI_ATTR_CHAR_SIZE in parameter handles, as a guide for setting OCI_ATTR_MAXDATA_SIZE
and OCI_ATTR_MAXCHAR_SIZE attributes in bind handles.
It is a good practice to specify OCI_ATTR_MAXDATA_SIZE and OCI_ATTR_MAXCHAR_SIZE to be
no more than the actual column width in bytes or characters.

7.8.3.3.3 Buffer Expansion During Inserts
Use OCI_ATTR_MAXDATA_SIZE to avoid unexpected behavior caused by buffer expansion
during inserts.
Consider what happens when the database column has character-length semantics,
and the user tries to insert data using OCIBindByPos() or OCIBindByPos2() or
OCIBindByName() or OCIBindByName2() while setting only the OCI_ATTR_MAXCHAR_SIZE to
3000 bytes. The database character set is UTF8 and the client character set is ASCII.
Then, in this case although 3000 characters fits in a buffer of size 3000 bytes for the
client, on the server side it might expand to more than 4000 bytes. Unless the
underlying column is a LONG or a LOB type, the server returns an error. To avoid this
problem specify the OCI_ATTR_MAXDATA_SIZE to be 4000 to guarantee that the Oracle
database never exceeds 4000 bytes.

See Also:
•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindByName() or OCIBindByName2()

7.8.3.4 Constraint Checking During Defining
To select data from columns into client buffers, OCI uses defined variables.
You can set an OCI_ATTR_MAXCHAR_SIZE value on the define buffer to impose an
additional character-length constraint. There is no OCI_ATTR_MAXDATA_SIZE attribute for
define handles because the buffer size in bytes serves as the limit on byte length. The
define buffer size provided in the OCIDefineByPos() or OCIDefineByPos2() call can be
used as the byte constraint.
This section includes the following topics:
•

Dynamic SQL Selects

•

Return Lengths

See Also:
OCIDefineByPos() or OCIDefineByPos2()

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7.8.3.4.1 Dynamic SQL Selects
When sizing buffers for dynamic SQL, always use the OCI_ATTR_DATA_SIZE value in the
implicit describe to avoid data loss through truncation.
If the database column is created using character-length semantics known through the
OCI_ATTR_CHAR_USED attribute, then you can use the OCI_ATTR_MAXCHAR_SIZE value to set
an additional constraint on the define buffer. A maximum number of
OCI_ATTR_MAXCHAR_SIZE characters is put in the buffer.

7.8.3.4.2 Return Lengths
The following return length values are always in bytes regardless of the characterlength semantics of the database.
•
•

The value returned in the alen, or the actual length field in binds and defines
The value that appears in the length, prefixed in special data types such as
VARCHAR and LONG VARCHAR

•

The value of the indicator variable in case of truncation

The only exception to this rule is for string buffers in the OCI_UTF16ID character set ID;
then the return lengths are in UTF-16 units.

Note:
The buffer sizes in the bind and define calls and the piece sizes in the
OCIStmtGetPieceInfo() and OCIStmtSetPieceInfo() and the callbacks are

always in bytes.

See Also:
•

OCIStmtGetPieceInfo()

•

OCIStmtSetPieceInfo()

7.8.3.5 General Compatibility Issues for Character-Length Semantics in OCI
Character-length semantics in OCI depends on the Oracle Database release, release
9.0 or later versus release 8.1 or earlier.
•

For a release 9.0 or later client communicating with a release 8.1 or earlier Oracle
Database, OCI_ATTR_MAXCHAR_SIZE is not known by the Oracle Database, so this
value is ignored. If you specify only this value, OCI derives the corresponding
OCI_ATTR_MAXDATA_SIZE value based on the maximum number of bytes for each
character for the client-side character set.

•

For a release 8.1 or earlier client communicating with a release 9.0 or later Oracle
Database, the client can never specify an OCI_ATTR_MAXCHAR_SIZE value, so the

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Oracle Database considers the client as always expecting byte-length semantics.
This is similar to the situation when the client specifies only OCI_ATTR_MAXDATA_SIZE.
So in both cases, the Oracle database and client can exchange information in an
appropriate manner.
This section includes the following topics:
•

Code Example for Inserting and Selecting Using OCI_ATTR_MAXCHAR_SIZE

•

Code Example for UTF-16 Binding and Defining

7.8.3.5.1 Code Example for Inserting and Selecting Using OCI_ATTR_MAXCHAR_SIZE
When a column is created by specifying a number N of characters, the actual allocation
in the database considers the worst case scenario.
This is shown in Example 7-19. The real number of bytes allocated is a multiple of N,
say M times N. Currently, M is 3 as the maximum number of bytes allocated for each
character in UTF-8.
For example, in Example 7-19, in the EMP table, the ENAME column is defined as 30
characters and the ADDRESS column is defined as 80 characters. Thus, the
corresponding byte lengths in the database are M*30 or 3*30=90, and M*80 or
3*80=240, respectively.
Example 7-19 Insert and Select Operations Using the
OCI_ATTR_MAXCHAR_SIZE Attribute
...
utext ename[31], address[81];
/* E' <= 30+ 1, D' <= 80+ 1, considering null-termination */
sb4 ename_max_chars = EC=20, address_max_chars = ED=60;
/* EC <= (E' - 1), ED <= (D' - 1) */
sb4 ename_max_bytes = EB=80, address_max_bytes = DB=200;
/* EB <= M * EC, DB <= M * DC */
text *insstmt = (text *)"INSERT INTO EMP(ENAME, ADDRESS) VALUES (:ENAME, \
:ADDRESS)";
text *selstmt = (text *)"SELECT ENAME, ADDRESS FROM EMP";
...
/* Inserting Column Data */
OCIStmtPrepare(stmthp1, errhp, insstmt, (ub4)strlen((char *)insstmt),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
OCIBindByName(stmthp1, &bnd1p, errhp, (text *)":ENAME",
(sb4)strlen((char *)":ENAME"),
(void *)ename, sizeof(ename), SQLT_STR, (void *)&insname_ind,
(ub2 *)alenp, (ub2 *)rcodep, (ub4)maxarr_len, (ub4 *)curelep, OCI_DEFAULT);
/* either */
OCIAttrSet((void *)bnd1p, (ub4)OCI_HTYPE_BIND, (void *)&ename_max_bytes,
(ub4)0, (ub4)OCI_ATTR_MAXDATA_SIZE, errhp);
/* or */
OCIAttrSet((void *)bnd1p, (ub4)OCI_HTYPE_BIND, (void *)&ename_max_chars,
(ub4)0, (ub4)OCI_ATTR_MAXCHAR_SIZE, errhp);
...
/* Retrieving Column Data */
OCIStmtPrepare(stmthp2, errhp, selstmt, strlen((char *)selstmt),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
OCIDefineByPos(stmthp2, &dfn1p, errhp, (ub4)1, (void *)ename,
(sb4)sizeof (ename),
SQLT_STR, (void *)&selname_ind, (ub2 *)alenp, (ub2 *)rcodep,
(ub4)OCI_DEFAULT);

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/* if not called, byte semantics is by default */
OCIAttrSet((void *)dfn1p, (ub4)OCI_HTYPE_DEFINE, (void *)&ename_max_chars,
(ub4)0,
(ub4)OCI_ATTR_MAXCHAR_SIZE, errhp);
...

7.8.3.5.2 Code Example for UTF-16 Binding and Defining
The character set ID in bind and define of the CHAR or VARCHAR2, or in NCHAR or NVARCHAR2
variant handles can be set to assume that all data is passed in UTF-16 (Unicode)
encoding. To specify UTF-16, set OCI_ATTR_CHARSET_ID = OCI_UTF16ID.
OCI provides a typedef called utext to facilitate binding and defining of UTF-16 data.
The internal representation of utext is a 16-bit unsigned integer, ub2. Operating
systems where the encoding scheme of the wchar_t data type conforms to UTF-16 can
easily convert utext to the wchar_t data type using cast operators.
Even for UTF-16 data, the buffer size in bind and define calls is assumed to be in
bytes. Users should use the utext data type as the buffer for input and output data.
Example 7-20 shows pseudocode that illustrates a bind and define for UTF-16 data.
Example 7-20

Binding and Defining UTF-16 Data

...
OCIStmt *stmthp1, *stmthp2;
OCIDefine *dfn1p, *dfn2p;
OCIBind *bnd1p, *bnd2p;
text *insstmt=
(text *) "INSERT INTO EMP(ENAME, ADDRESS) VALUES (:ename, :address)"; \
text *selname =
(text *) "SELECT ENAME, ADDRESS FROM EMP";
utext ename[21]; /* Name UTF-16 */
utext address[51]; /* Address - UTF-16 */
ub2 csid = OCI_UTF16ID;
sb4 ename_col_len = 20;
sb4 address_col_len = 50;
...
/* Inserting UTF-16 data */
OCIStmtPrepare (stmthp1, errhp, insstmt, (ub4)strlen ((char *)insstmt),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
OCIBindByName (stmthp1, &bnd1p, errhp, (text*)":ENAME",
(sb4)strlen((char *)":ENAME"),
(void *) ename, sizeof(ename), SQLT_STR,
(void *)&insname_ind, (ub2 *) 0, (ub2 *) 0, (ub4) 0,
(ub4 *)0, OCI_DEFAULT);
OCIAttrSet ((void *) bnd1p, (ub4) OCI_HTYPE_BIND, (void *) &csid,
(ub4) 0, (ub4)OCI_ATTR_CHARSET_ID, errhp);
OCIAttrSet((void *) bnd1p, (ub4) OCI_HTYPE_BIND, (void *) &ename_col_len,
(ub4) 0, (ub4)OCI_ATTR_MAXDATA_SIZE, errhp);
...
/* Retrieving UTF-16 data */
OCIStmtPrepare (stmthp2, errhp, selname, strlen((char *) selname),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
OCIDefineByPos (stmthp2, &dfn1p, errhp, (ub4)1, (void *)ename,
(sb4)sizeof(ename), SQLT_STR,
(void *)0, (ub2 *)0, (ub2 *)0, (ub4)OCI_DEFAULT);
OCIAttrSet ((void *) dfn1p, (ub4) OCI_HTYPE_DEFINE, (void *) &csid,
(ub4) 0, (ub4)OCI_ATTR_CHARSET_ID, errhp);
...

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PL/SQL REF CURSORs and Nested Tables in OCI

See Also:
Bind Handle Attributes

7.9 PL/SQL REF CURSORs and Nested Tables in OCI
OCI provides the ability to bind and define PL/SQL REF CURSORs and nested tables.
An application can use a statement handle to bind and define these types of variables.
As an example, consider this PL/SQL block:
static const text *plsql_block = (text *)
"begin \
OPEN :cursor1 FOR SELECT employee_id, last_name, job_id, manager_id, \
salary, department_id \
FROM employees WHERE job_id=:job ORDER BY employee_id; \
OPEN :cursor2 FOR SELECT * FROM departments ORDER BY department_id;
end;";

An application allocates a statement handle for binding by calling OCIHandleAlloc(),
and then binds the :cursor1 placeholder to the statement handle, as in the following
code, where :cursor1 is bound to stm2p.
In this code in Example 7-21, stm1p is the statement handle for the PL/SQL block,
whereas stm2p is the statement handle that is bound as a REF CURSOR for later data
retrieval. A value of SQLT_RSET is passed for the dty parameter.
As another example, consider the following:
static const text *nst_tab = (text *)
"SELECT last_name, CURSOR(SELECT department_name, location_id \
FROM departments) FROM employees WHERE last_name = 'FORD'";

The second position is a nested table, which an OCI application can define as a
statement handle shown in Example 7-22.
After execution, when you fetch a row into stm2p it becomes a valid statement handle.

Note:
If you have retrieved multiple REF CURSORs, you must take care when fetching
them into stm2p. If you fetch the first one, you can then perform fetches on it
to retrieve its data. However, after you fetch the second REF CURSOR into stm2p,
you no longer have access to the data from the first REF CURSOR.
OCI does not support PL/SQL REF CURSORs that were executed in scrollable
mode.
OCI does not support scrollable REF CURSORs because you cannot scroll back
to the rows already fetched by a REF CURSOR.

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Example 7-21 Binding the :cursor1 Placeholder to the Statement Handle stm2p
as a REF CURSOR
status = OCIStmtPrepare (stm1p, errhp, (text *) plsql_block,
strlen((char *)plsql_block), OCI_NTV_SYNTAX, OCI_DEFAULT);
...
status = OCIBindByName (stm1p, (OCIBind **) &bnd1p, errhp,
(text *)":cursor1", (sb4)strlen((char *)":cursor1"),
(void *)&stm2p, (sb4) 0, SQLT_RSET, (void *)0,
(ub2 *)0, (ub2 *)0, (ub4)0, (ub4 *)0, (ub4)OCI_DEFAULT);

Example 7-22
Handle

Defining a Nested Table (Second Position) as a Statement

status = OCIStmtPrepare (stm1p, errhp, (text *) nst_tab,
strlen((char *)nst_tab), OCI_NTV_SYNTAX, OCI_DEFAULT);
...
status = OCIDefineByPos (stm1p, (OCIDefine **) &dfn2p, errhp, (ub4)2,
(void *)&stm2p, (sb4)0, SQLT_RSET, (void *)0, (ub2 *)0,
(ub2 *)0, (ub4)OCI_DEFAULT);

See Also:
OCIHandleAlloc()

7.10 Natively Describe and Bind All PL/SQL Types Including
Package Types
Beginning with Oracle Database Release 12.1, OCI clients support the ability to
natively describe and bind all PL/SQL types.
This includes the base scalar type Boolean, which was previously unsupported as a
bind type. This also includes types declared in PL/SQL packages, such as named
record or collection type (including nested table, varray and index table) or implicit
record subtype (%rowtype) declared inside of a PL/SQL package specification. Native
support for these features means clients can describe and bind PL/SQL types using
only the provided client-side APIs.
The PL/SQL typecodes for these data types (Boolean, record, index-by
BINARY_INTEGER, and PLS_INTEGER or BINARY_INTEGER) are listed in Table 5-10. The
equivalent SQLT type for these PL/SQL typecodes is listed in Table 5-11. Clients must
bind the specified type using the respective specified value of SQLT type as the DTY of
the bind. For example, for records, clients must bind package record types
(OCI_TYPECODE_RECORD) using SQLT_NTY as the DTY of the bind; for collections, clients
must bind all package collection types (OCI_TYPECODE_ITABLE) using SQLT_NTY as the
DTY of the bind; and for Booleans, clients must bind Boolean types
(OCI_TYPECODE_BOOLEAN) using SQLT_BOL as the DTY of the bind. Bind APIs:
OCIBindByName(), OCIBindByName2(), OCIBindByPos(), and OCIBindByPos2() support each
SQLT type value in the DTY of the bind that represents these PL/SQL typecodes.

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See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

7.11 Runtime Data Allocation and Piecewise Operations in
OCI
You can use OCI to perform piecewise inserts, updates, and fetches of data.
You can also use OCI to provide data dynamically in case of array inserts or updates,
instead of providing a static array of bind values. You can insert or retrieve a very large
column as a series of chunks of smaller size, minimizing client-side memory
requirements.
The size of individual pieces is determined at run time by the application and can be
uniform or not.
The piecewise functionality of OCI is particularly useful when performing operations on
extremely large blocks of string or binary data, operations involving database columns
that store CLOB, BLOB, LONG, RAW, or LONG RAW data.
The piecewise fetch is complete when the final OCIStmtFetch2() call returns a value of
OCI_SUCCESS.
In both the piecewise fetch and insert, it is important to understand the sequence of
calls necessary for the operation to complete successfully. For a piecewise insert, you
must call OCIStmtExecute() one time more than the number of pieces to be inserted (if
callbacks are not used). This is because the first time OCIStmtExecute() is called, it
returns a value indicating that the first piece to be inserted is required. As a result, if
you are inserting n pieces, you must call OCIStmtExecute() a total of n+1 times.
Similarly, when performing a piecewise fetch, you must call OCIStmtFetch2() once more
than the number of pieces to be fetched.
This section includes the following topics:
•

Valid Data Types for Piecewise Operations

•

Types of Piecewise Operations

•

About Providing INSERT or UPDATE Data at Runtime

•

Piecewise Operations with PL/SQL

•

PL/SQL Indexed Table Binding Support

•

About Providing FETCH Information at Run Time

•

Piecewise Binds and Defines for LOBs

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See Also:
•

OCIStmtFetch2()

•

OCIStmtExecute()

7.11.1 Valid Data Types for Piecewise Operations
Only some data types can be manipulated in pieces.
OCI applications can perform piecewise fetches, inserts, or updates of all the following
data types:
•

VARCHAR2

•

STRING

•

LONG

•

LONG RAW

•

RAW

•

CLOB

•

BLOB

Another way of using this feature for all data types is to provide data dynamically for
array inserts or updates. The callbacks should always specify OCI_ONE_PIECE for the
piecep parameter of the callback for data types that do not support piecewise
operations.

7.11.2 Types of Piecewise Operations
What are the ways you can perform piecewise operations.
You can perform piecewise operations in two ways:
•

Use calls provided in the OCI library to execute piecewise operations under a
polling paradigm.

•

Employ user-defined callback functions to provide the necessary information and
data blocks.

When you set the mode parameter of an OCIBindByPos() or OCIBindByPos2() or
OCIBindByName() or OCIBindByName2() call to OCI_DATA_AT_EXEC, it indicates that an OCI
application is providing data for an INSERT or UPDATE operation dynamically at runtime.
Similarly, when you set the mode parameter of an OCIDefineByPos() or
OCIDefineByPos2() call to OCI_DYNAMIC_FETCH, it indicates that an application dynamically
provides allocation space for receiving data at the time of the fetch.
In each case, you can provide the runtime information for the INSERT, UPDATE, or FETCH
operation in one of two ways: through callback functions, or by using piecewise
operations. If callbacks are desired, an additional bind or define call is necessary to
register the callbacks.

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The following sections give specific information about runtime data allocation and
piecewise operations for inserts, updates, and fetches.

Note:
Piecewise operations are also valid for SQL and PL/SQL blocks.

See Also:
•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindByName() or OCIBindByName2()

•

OCIDefineByPos() or OCIDefineByPos2()

7.11.3 About Providing INSERT or UPDATE Data at Runtime
When you specify the OCI_DATA_AT_EXEC mode in a call to OCIBindByPos() or
OCIBindByPos2() or OCIBindByName() or OCIBindByName2(), the value_sz parameter
defines the total size of the data that can be provided at run time.
The application must be ready to provide to the OCI library the run time IN data buffers
on demand as many times as is necessary to complete the operation. When the
allocated buffers are no longer required, they must be freed by the client.
Runtime data is provided in one of two ways:
•

You can define a callback using the OCIBindDynamic() function, which when called
at run time returns either a piece of the data or all of it.

•

If no callbacks are defined, the call to OCIStmtExecute() to process the SQL
statement returns the OCI_NEED_DATA error code. The client application then
provides the IN/OUT data buffer or piece using the OCIStmtSetPieceInfo() call that
specifies which bind and piece are being used.

This section includes the following topic: Performing a Piecewise Insert or Update.

See Also:
•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindDynamic()

•

OCIStmtExecute()

•

OCIStmtSetPieceInfo()

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7.11.3.1 Performing a Piecewise Insert or Update
Once the OCI environment has been initialized, and a database connection and
session have been established, a piecewise insert begins with calls to prepare a SQL
or PL/SQL statement and to bind input values.
Piecewise operations using standard OCI calls rather than user-defined callbacks do
not require a call to OCIBindDynamic().

Note:
Additional bind variables that are not part of piecewise operations may
require additional bind calls, depending on their data types.

Following the statement preparation and bind, the application performs a series of
calls to OCIStmtExecute(), OCIStmtGetPieceInfo(), and OCIStmtSetPieceInfo() to
complete the piecewise operation. Each call to OCIStmtExecute() returns a value that
determines what action should be performed next. In general, the application retrieves
a value indicating that the next piece must be inserted, populates a buffer with that
piece, and then executes an insert. When the last piece has been inserted, the
operation is complete.
Keep in mind that the insert buffer can be of arbitrary size and is provided at run time.
In addition, each inserted piece does not need to be of the same size. The size of
each piece to be inserted is established by each OCIStmtSetPieceInfo() call.

Note:
If the same piece size is used for all inserts, and the size of the data being
inserted is not evenly divisible by the piece size, the final inserted piece is
expected to be smaller. You must account for this by indicating the smaller
size in the final OCIStmtSetPieceInfo() call.

The procedure is illustrated in Figure 7-3 and expanded in the steps following the
figure.

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Figure 7-3

Performing Piecewise Insert

1.

Initialize the OCI environment, allocate the necessary handles, connect to a
server, authorize a user, and prepare a statement request by using
OCIStmtPrepare2().

2.

Bind a placeholder by using OCIBindByName() or OCIBindByName2() or OCIBindByPos()
or OCIBindByPos2(). You do not need to specify the actual size of the pieces you
use, but you must provide the total size of the data that can be provided at run
time.

3.

Call OCIStmtExecute() for the first time. No data is being inserted here, and the
OCI_NEED_DATA error code is returned to the application. If any other value is
returned, it indicates that an error occurred.

4.

5.

Call OCIStmtGetPieceInfo() to retrieve information about the piece that must be
inserted. The parameters of OCIStmtGetPieceInfo() include a pointer to a value
indicating if the required piece is the first piece, OCI_FIRST_PIECE, or a subsequent
piece, OCI_NEXT_PIECE.
The application populates a buffer with the piece of data to be inserted and calls
OCIStmtSetPieceInfo() with these parameters:

6.

•

A pointer to the piece

•

A pointer to the length of the piece

•

A value indicating whether this is the first piece (OCI_FIRST_PIECE), an
intermediate piece (OCI_NEXT_PIECE), or the last piece (OCI_LAST_PIECE)

Call OCIStmtExecute() again. If OCI_LAST_PIECE was indicated in Step 5 and
OCIStmtExecute() returns OCI_SUCCESS, all pieces were inserted successfully. If
OCIStmtExecute() returns OCI_NEED_DATA, go back to Step 3 for the next insert. If
OCIStmtExecute() returns any other value, an error occurred.

The piecewise operation is complete when the final piece has been successfully
inserted. This is indicated by the OCI_SUCCESS return value from the final
OCIStmtExecute() call.

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Piecewise updates are performed in a similar manner. In a piecewise update operation
the insert buffer is populated with data that is being updated, and OCIStmtExecute() is
called to execute the update.

See Also:
•

Polling Mode Operations in OCI

•

OCIBindDynamic()

•

OCIStmtExecute()

•

OCIStmtGetPieceInfo()

•

OCIStmtSetPieceInfo()

•

OCIStmtPrepare2()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

7.11.4 Piecewise Operations with PL/SQL
An OCI application can perform piecewise operations with PL/SQL for IN, OUT, and
IN/OUT bind variables in a method similar to that outlined previously.

Keep in mind that all placeholders in PL/SQL statements are bound, rather than
defined. The call to OCIBindDynamic() specifies the appropriate callbacks for OUT or
IN/OUT parameters.

See Also:
OCIBindDynamic()

7.11.5 PL/SQL Indexed Table Binding Support
PL/SQL indexed tables can be passed as IN/OUT binds into PL/SQL anonymous blocks
using OCI.
The procedure for binding PL/SQL indexed tables is quite similar to performing an
array bind for SQL statements. The OCI program must bind the location of an array
with other metadata for the array as follows, using either OCIBindByName() or
OCIBindByName2() or OCIBindByPos() or OCIBindByPos2(). The process of binding a C
array into a PL/SQL indexed table bind variable must provide the following information
during the bind call:
•

void *valuep (IN/OUT) - A pointer to a location that specifies the beginning of the

array in client memory
•

ub2 dty (IN) - The data type of the elements of the array as represented on the

client

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•

sb4 value_sz (IN) - The maximum size (in bytes) of each element of the array as

represented on the client
•

ub4 maxarr_len (IN) - The maximum number of elements of the data type the array

is expected to hold in its lifetime
If allocating the entire array up front for doing static bindings, the array must be
sized sufficiently to contain maxarr_len number of elements, each of size value_sz.
This information is also used to constrain the indexed table as seen by PL/SQL.
PL/SQL cannot look up the indexed table (either for read or write) beyond this
specified limit.
•

ub4 *curelep (IN/OUT) - A pointer to the number of elements in the array (from the

beginning of the array) that are currently valid.
This should be less than or equal to the maximum array length. Note that this
information is also used to constrain the indexed table as seen by PL/SQL. For IN
binds, PL/SQL cannot read from the indexed table beyond this specified limit. For
OUT binds, PL/SQL can write to the indexed table beyond this limit, but not beyond
the maxarr_len limit.
For IN indexed table binds, before performing OCIStmtExecute(), the user must set up
the current array length (*curelep) for that execution. In addition, the user also must
set up the actual length and indicator as applicable for each element of the array.
For OUT binds, OCI must return the current array length (*curelep) and the actual
length, indicator and return code as applicable for each element of the array.
For best performance, keep the array allocated with maximum array length, and then
vary the current array length between executes based on how many elements are
actually being passed back and forth. Such an approach does not require repeatedly
deallocating and reallocating the array for every execute, thereby helping overall
application performance.
It is also possible to bind using OCI piecewise calls for PL/SQL indexed tables. Such
an approach does not require preallocating the entire array up front. The
OCIStmtSetPieceInfo() and OCIStmtGetPieceInfo() calls can be used to pass in
individual elements piecewise.
This section includes the following topic: Restrictions for PL/SQL Indexed Table
Binding Interface.

See Also:
•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIStmtExecute()

•

OCIStmtSetPieceInfo()

•

OCIStmtGetPieceInfo()

7.11.5.1 Restrictions for PL/SQL Indexed Table Binding Interface
What are the restrictions for the PL/SQL indexed table OCI binding interface.

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The PL/SQL indexed table OCI binding interface does not support binding:
•

Arrays of ADTs or REFs

•

Arrays of descriptor types such as LOB descriptors, ROWID descriptors, datetime
or interval descriptors

•

Arrays of PLSQL record types

7.11.6 About Providing FETCH Information at Run Time
When a call is made to OCIDefineByPos() or OCIDefineByPos2() with the mode parameter
set to OCI_DYNAMIC_FETCH, an application can specify information about the data buffer
at the time of fetch.
You may also need to call OCIDefineDynamic() to set a callback function that is invoked
to get information about your data buffer.
Runtime data is provided in one of two ways:
•

You can define a callback using the OCIDefineDynamic() function. The value_sz
parameter defines the maximum size of the data that is provided at run time.
When the client library needs a buffer to return the fetched data, the callback is
invoked to provide a runtime buffer into which either a piece of the data or all of it
is returned.

•

If no callbacks are defined, the OCI_NEED_DATA error code is returned and the OUT
data buffer or piece can then be provided by the client application by using
OCIStmtSetPieceInfo(). The OCIStmtGetPieceInfo() call provides information about
which define and which piece are involved.

This section includes the following topic: Performing a Piecewise Fetch

See Also:
•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIDefineDynamic()

•

OCIStmtSetPieceInfo()

•

OCIStmtGetPieceInfo()

7.11.6.1 Performing a Piecewise Fetch
The fetch buffer can be of arbitrary size. In addition, each fetched piece does not need
to be of the same size.
The only requirement is that the size of the final fetch must be exactly the size of the
last remaining piece. The size of each piece to be fetched is established by each
OCIStmtSetPieceInfo() call. This process is illustrated in Figure 7-4 and explained in
the steps following the figure.

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Figure 7-4

Performing Piecewise Fetch

1.

Initialize the OCI environment, allocate necessary handles, connect to a database,
authorize a user, prepare a statement, and execute the statement by using
OCIStmtExecute().

2.

Define an output variable by using OCIDefineByPos() or OCIDefineByPos2(), with
mode set to OCI_DYNAMIC_FETCH. At this point you do not need to specify the actual
size of the pieces you use, but you must provide the total size of the data that is to
be fetched at run time.

3.

Call OCIStmtFetch2() for the first time. No data is retrieved, and the OCI_NEED_DATA
error code is returned to the application. If any other value is returned, then an
error occurred.

4.

Call OCIStmtGetPieceInfo() to obtain information about the piece to be fetched. The
piecep parameter indicates whether it is the first piece (OCI_FIRST_PIECE), a
subsequent piece (OCI_NEXT_PIECE), or the last piece (OCI_LAST_PIECE).

5.

Call OCIStmtSetPieceInfo() to specify the fetch buffer.

6.

Call OCIStmtFetch2() again to retrieve the actual piece. If OCIStmtFetch2() returns
OCI_SUCCESS, all the pieces have been fetched successfully. If OCIStmtFetch2()
returns OCI_NEED_DATA, return to Step 4 to process the next piece. If any other value
is returned, an error occurred.

See Also:
•

Polling Mode Operations in OCI

•

OCIStmtSetPieceInfo()

•

OCIStmtExecute()

•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIStmtGetPieceInfo()

•

OCIStmtFetch2()

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7.11.7 Piecewise Binds and Defines for LOBs
What are the ways of doing piecewise binds and defines for LOBs.
There are two:
•

Using the data interface
You can bind or define character data for CLOB columns using SQLT_CHR (VARCHAR2)
or SQLT_LNG (LONG) as the input data type for the following functions. You can also
bind or define raw data for BLOB columns using SQLT_LBI (LONG RAW), and SQLT_BIN
(RAW) as the input data type for these functions:
–

OCIDefineByPos() or OCIDefineByPos2()

–

OCIBindByName() or OCIBindByName2()

–

OCIBindByPos() or OCIBindByPos2()

All the piecewise operations described later are supported for CLOB and BLOB
columns in this case.
•

Using the LOB locator
You can bind or define a LOB locator for CLOB and BLOB columns using SQLT_CLOB
(CLOB) or SQLT_BLOB (BLOB) as the input data type for the following functions.
–

OCIDefineByPos() or OCIDefineByPos2()

–

OCIBindByName() or OCIBindByName2()

–

OCIBindByPos() or OCIBindByPos2()

You must then call OCILob* functions to read and manipulate the data.
OCILobRead2() and OCILobWrite2() support piecewise and callback modes.

See Also:
•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

About Binding LOB Data for usage and examples for both INSERT and
UPDATE statements

•

About Defining LOB Data for usage and examples of SELECT statements

•

OCILobRead2()

•

OCILobWrite2()

•

LOB Read and Write Callbacks for information about streaming using
callbacks with OCILobWrite2() and OCILobRead2()

7-54

8
Describing Schema Metadata
This chapter discusses the use of the OCIDescribeAny() function to obtain information
about schema elements.
This chapter contains these topics:
•

About Using OCIDescribeAny()

•

Parameter Attributes

•

Character-Length Semantics Support in Describe Operations

•

Examples Using OCIDescribeAny()

See Also:
OCIDescribeAny()

8.1 About Using OCIDescribeAny()
Performs an explicit describe of schema objects and their subschema objects.
The OCIDescribeAny() function enables you to perform an explicit describe of the
following schema objects and their subschema objects:
•

Tables and views

•

Synonyms

•

Procedures

•

Functions

•

Packages

•

Sequences

•

Collections

•

Types

•

Schemas

•

Databases

Information about other schema elements (function arguments, columns, type
attributes, and type methods) is available through a describe of one of the preceding
schema objects or an explicit describe of the subschema object.
When an application describes a table, it can then retrieve information about that
table's columns. Additionally, OCIDescribeAny() can directly describe subschema
objects such as columns of a table, packages of a function, or fields of a type if given
the name of the subschema object.

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About Using OCIDescribeAny()

The OCIDescribeAny() call requires a describe handle as one of its arguments. The
describe handle must be previously allocated with a call to OCIHandleAlloc().
The information returned by OCIDescribeAny() is organized hierarchically like a tree, as
shown in Figure 8-1.

Figure 8-1

OCIDescribeAny() Table Description

The describe handle returned by the OCIDescribeAny() call has an attribute,
OCI_ATTR_PARAM, that points to such a description tree. Each node of the tree has
attributes associated with that node, as well as attributes that are like recursive
describe handles and point to subtrees containing further information. If all the
attributes are homogenous, as with elements of a column list, they are called
parameters. The attributes associated with any node are returned by OCIAttrGet(), and
the parameters are returned by OCIParamGet().
A call to OCIAttrGet() on the describe handle for the table returns a handle to the
column-list information. An application can then use OCIParamGet() to retrieve the
handle to the column description of a particular column in the column list. The handle
to the column descriptor can be passed to OCIAttrGet() to get further information about
the column, such as the name and data type.
After a SQL statement is executed, information about the select list is available as an
attribute of the statement handle. No explicit describe call is needed. To retrieve
information about select-list items from the statement handle, the application must call
OCIParamGet() once for each position in the select list to allocate a parameter descriptor
for that position.

Note:
No subsequent OCIAttrGet() or OCIParamGet() call requires extra round-trips,
as the entire description is cached on the client side by OCIDescribeAny().

This section includes the following topics:

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Chapter 8

About Using OCIDescribeAny()

•

Limitations on OCIDescribeAny()

•

Notes on Types and Attributes

See Also:
•

OCIDescribeAny()

•

OCIHandleAlloc()

•

OCIAttrGet()

•

OCIParamGet()

8.1.1 Limitations on OCIDescribeAny()
The OCIDescribeAny() call limits information returned to the basic information and stops
expanding a node if it amounts to another describe operation.
For example, if a table column is of an object type, then OCI does not return a subtree
describing the type, because this information can be obtained by another describe call.
The table name is not returned by OCIDescribeAny() or the implicit use of
OCIStmtExecute(). Sometimes a column is not associated with a table. In most cases,
the table is already known.

See Also:
•

About Describing Select-List Items

•

OCIDescribeAny()

•

OCIStmtExecute()

8.1.2 Notes on Types and Attributes
What to be aware of when performing describe operations.
When performing describe operations, you should be aware of the following topics:
•

Data Type Codes

•

About Describing Types

•

Implicit and Explicit Describe Operations

•

OCI_ATTR_LIST_ARGUMENTS Attribute

8.1.2.1 Data Type Codes
The OCI_ATTR_TYPECODE attribute returns typecodes that represent the types supplied by
the user when a new type is created using the CREATE TYPE statement.

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About Using OCIDescribeAny()

These typecodes are of the enumerated type OCITypeCode, and are represented by
OCI_TYPECODE constants. Internal PL/SQL type (boolean) is supported.
The OCI_ATTR_DATA_TYPE attribute returns typecodes that represent the data types
stored in database columns. These are similar to the describe values returned by
previous versions of Oracle Database. These values are represented by SQLT
constants (ub2 values). Boolean types return SQLT_BOL.

See Also:
•
•

External Data Types for more information about SQLT_BOL
Typecodes for more information about typecodes, such as the
OCI_TYPECODE values returned in the OCI_ATTR_TYPECODE attribute and the
SQLT typecodes returned in the OCI_ATTR_DATA_TYPE attribute

8.1.2.2 About Describing Types
To describe type objects, it is necessary to initialize the OCI process in object mode.
This is shown in Example 8-1.
Example 8-1

Initializing the OCI Process in Object Mode

/* Initialize the OCI Process */
if (OCIEnvCreate((OCIEnv **) &envhp, (ub4) OCI_OBJECT, (voivoid *) 0,
(void * (*)(void *,size_t)) 0,
(void * (*)(void *, void *, size_t)) 0,
(void (*)(void *, void *)) 0, (size_t) 0, (void **) 0))
{
printf("FAILED: OCIEnvCreate()\n");
return OCI_ERROR;
}

See Also:
OCIEnvCreate()

8.1.2.3 Implicit and Explicit Describe Operations
The column attribute OCI_ATTR_PRECISION can be returned using an implicit describe
with OCIStmtExecute() and an explicit describe with OCIDescribeAny().
When you use an implicit describe, set the precision to sb2. When you use an explicit
describe, set the precision to ub1 for a placeholder. This is necessary to match the
data type of precision in the dictionary.

8-4

Chapter 8

Parameter Attributes

See Also:
•

OCIStmtExecute()

•

OCIDescribeAny()

8.1.2.4 OCI_ATTR_LIST_ARGUMENTS Attribute
The OCI_ATTR_LIST_ARGUMENTS attribute for type methods represents second-level
arguments for the method.
For example, consider the following record my_type and the procedure my_proc that
takes an argument of type my_type:
my_type record(a number, b char)
my_proc (my_input my_type)

In this example, the OCI_ATTR_LIST_ARGUMENTS attribute would apply to arguments a and
b of the my_type record.

8.2 Parameter Attributes
This section describes the attributes and handles that belong to different parameters.
A parameter is returned by OCIParamGet(). Parameters can describe different types of
objects or information, and have attributes depending on the type of description they
contain, or type-specific attributes.
The OCIDescribeAny() call does support more than two name components (for
example, schema.type.attr1.attr2.method1). With more than one component, the first
component is interpreted as the schema name (unless some other flag is set). There is
a flag to specify that the object must be looked up under PUBLIC, that is, describe "a",
where "a" can be either in the current schema or a public synonym.
If you do not know what the object type is, specify OCI_PTYPE_UNK. Otherwise, an error is
returned if the actual object type does not match the specified type.
Table 8-1 lists the attributes of all parameters.
Table 8-1

Attributes of All Parameters

Attribute

Description

Attribute Data Type

OCI_ATTR_OBJ_ID

Object or schema ID

ub4

OCI_ATTR_OBJ_NAME

Database name or object name in a schema

OraText *

OCI_ATTR_OBJ_SCHEMA

Schema name where the object is located

OraText *

8-5

Chapter 8

Parameter Attributes

Table 8-1

(Cont.) Attributes of All Parameters

Attribute

Description

Attribute Data Type

OCI_ATTR_PTYPE

Type of information described by the parameter. Possible
ub1
values:
OCI_PTYPE_TABLE - table
OCI_PTYPE_VIEW - view
OCI_PTYPE_PROC - procedure
OCI_PTYPE_FUNC - function
OCI_PTYPE_PKG - package
OCI_PTYPE_TYPE - type, including a package type
OCI_PTYPE_TYPE_ATTR - attribute of a type, including
package record type attributes
OCI_PTYPE_TYPE_COLL - collection type information,
including package collection elements
OCI_PTYPE_TYPE_METHOD - method of a type
OCI_PTYPE_SYN - synonym
OCI_PTYPE_SEQ - sequence
OCI_PTYPE_COL - column of a table or view
OCI_PTYPE_ARG - argument of a function or procedure
OCI_PTYPE_TYPE_ARG - argument of a type method
OCI_PTYPE_TYPE_RESULT - results of a method
OCI_PTYPE_LIST - column list for tables and views,
argument list for functions and procedures, or
subprogram list for packages
OCI_PTYPE_SCHEMA - schema
OCI_PTYPE_DATABASE - database
OCI_PTYPE_UNK - unknown schema object

OCI_ATTR_TIMESTAMP

The time stamp of the object on which the description is
based in Oracle date format

ub1 *

The following sections list the attributes and handles specific to different types of
parameters:
•

Table or View Parameters

•

Procedure, Function, and Subprogram Attributes

•

Package Attributes

•

Type Attributes

•

Type Attribute Attributes

•

Type Method Attributes

•

Collection Attributes

•

Synonym Attributes

•

Sequence Attributes

•

Column Attributes

•

Argument and Result Attributes

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Chapter 8

Parameter Attributes

•

List Attributes

•

Schema Attributes

•

Database Attributes

•

Rule Attributes

•

Rule Set Attributes

•

Evaluation Context Attributes

•

Table Alias Attributes

•

Variable Type Attributes

•

Name Value Attributes

See Also:
•

OCIParamGet()

•

OCIDescribeAny()

8.2.1 Table or View Parameters
Lists and describes the type-specific attributes for parameters for a table or view.
Table 8-2 lists the type-specific attributes for parameters for a table or view (type
OCI_PTYPE_TABLE or OCI_PTYPE_VIEW).

Table 8-2

Attributes of Tables or Views

Attribute

Description

Attribute Data Type

OCI_ATTR_OBJID

Object ID

ub4

OCI_ATTR_NUM_COLS

Number of columns

ub2

OCI_ATTR_LIST_COLUMNS

Column list (type OCI_PTYPE_LIST)

OCIParam *

OCI_ATTR_REF_TDO

REF to the type description object (TDO) of the
base type for extent tables

OCI_ATTR_IS_TEMPORARY

Indicates that the table is temporary

ub1

OCI_ATTR_IS_TYPED

Indicates that the table is typed

ub1

OCI_ATTR_DURATION

Duration of a temporary table. Values can be:

OCIDuration

OCI_DURATION_SESSION - session

OCIRef *

OCI_DURATION_TRANS - transaction
OCI_DURATION_NULL - table not temporary

Table 8-3 lists additional attributes that belong to tables.

8-7

Chapter 8

Parameter Attributes

Table 8-3

Attributes Specific to Tables

Attribute

Description

Attribute Data Type

OCI_ATTR_RDBA

Data block address of the segment header

ub4

OCI_ATTR_TABLESPACE

Tablespace that the table resides in

word

OCI_ATTR_CLUSTERED

Indicates that the table is clustered

ub1

OCI_ATTR_PARTITIONED

Indicates that the table is partitioned

ub1

OCI_ATTR_INDEX_ONLY

Indicates that the table is index-only

ub1

8.2.2 Procedure, Function, and Subprogram Attributes
Lists and describes the type-specific attributes when a parameter is for a procedure or
function.
Table 8-4 lists the type-specific attributes when a parameter is for a procedure or
function (type OCI_PTYPE_PROC or OCI_PTYPE_FUNC).
Table 8-4

Attributes of Procedures or Functions

Attribute

Description

Attribute
Data Type

OCI_ATTR_LIST_ARGUMEN Argument list. See List Attributes.
TS

void *

OCI_ATTR_IS_INVOKER_R Indicates that the procedure or function has invoker's rights
IGHTS

ub1

Table 8-5 lists the attributes that are defined only for package subprograms.
Table 8-5

Attributes Specific to Package Subprograms

Attribute

Description

Attribute Data Type

OCI_ATTR_NAME

Name of the procedure or function

OraText *

OCI_ATTR_OVERLOAD_ID

Overloading ID number (relevant in case the
ub2
procedure or function is part of a package and
is overloaded). Values returned may be different
from direct query of a PL/SQL function or
procedure.

8-8

Chapter 8

Parameter Attributes

8.2.3 Package Attributes
Lists and describes the attributes when a parameter is for a package.
Table 8-6 lists the attributes when a parameter is for a package (type OCI_PTYPE_PKG).
Table 8-6

Attributes of Packages

Attribute

Description

Attribute
Data Type

OCI_ATTR_LIST_PKG_TYPE Get a list of all types in an OCI_PTYPE_PKG package parameter handle.
S

void *

OCI_ATTR_LIST_SUBPROGR Subprogram list. See List Attributes.
AMS

void *

OCI_ATTR_IS_INVOKER_RI Indicates that the package has invoker's rights?
GHTS

ub1

8.2.4 Type Attributes
Lists and describes the attributes when a parameter is for a type.
Table 8-7 lists the attributes when a parameter is for a type (type OCI_PTYPE_TYPE).
These attributes are only valid if the application initialized the OCI process in
OCI_OBJECT mode in a call to OCIEnvCreate().
Table 8-7

Attributes of Types

Attribute

Description

Attribute
Data
Type

OCI_ATTR_REF_TDO

Returns the in-memory REF of the type descriptor object (TDO) for the
type, if the column type is an object type. If space has not been reserved
for the OCIRef, then it is allocated implicitly in the cache. The caller can
then pin the TDO with OCIObjectPin().

OCI_ATTR_TYPECODE

Typecode. See Data Type Codes. Currently can be only
OCI_TYPECODE_OBJECT, OCI_TYPECODE_NAMEDCOLLECTION, or
OCI_TYPECODE_RECORD.

OCI_ATTR_COLLECTION_TYP
ECODE

Typecode of collection if type is collection; invalid otherwise. See Data
Type Codes. Currently can be only OCI_TYPECODE_VARRAY,
OCI_TYPECODE_TABLE, or OCI_TYPECODE_ITABLE. If this attribute is queried
for a type that is not a collection, an error is returned.

OCI_ATTR_IS_INCOMPLETE_
TYPE

Indicates that this is an incomplete type

ub1

OCI_ATTR_IS_SYSTEM_TYPE

Indicates that this is a system type

ub1

OCI_ATTR_IS_PREDEFINED_
TYPE

Indicates that this is a predefined type

ub1

OCI_ATTR_IS_TRANSIENT_T
YPE

Indicates that this is a transient type

ub1

OCIRef *

OCITypeCo
de
OCITypeCo
de

8-9

Chapter 8

Parameter Attributes

Table 8-7

(Cont.) Attributes of Types

Attribute

Description

Attribute
Data
Type

OCI_ATTR_IS_SYSTEM_GENE
RATED_TYPE

Indicates that this is a system-generated type

ub1

OCI_ATTR_HAS_NESTED_TAB
LE

This type contains a nested table attribute.

ub1

OCI_ATTR_HAS_LOB

This type contains a LOB attribute.

ub1

OCI_ATTR_HAS_FILE

This type contains a BFILE attribute.

ub1

OCI_ATTR_COLLECTION_ELE
MENT

Handle to collection element. See Collection Attributes.

void *

OCI_ATTR_NUM_TYPE_ATTRS

Number of type attributes

ub2

OCI_ATTR_LIST_TYPE_ATTR
S

List of type attributes. See List Attributes.

void *

OCI_ATTR_NUM_TYPE_METHO
DS

Number of type methods

ub2

OCI_ATTR_LIST_TYPE_METH
ODS

List of type methods. See List Attributes.

void *

OCI_ATTR_MAP_METHOD

Map method of type. See Type Method Attributes.

void *

OCI_ATTR_ORDER_METHOD

Order method of type. See Type Method Attributes.

void *

OCI_ATTR_IS_INVOKER_RIG
HTS

Indicates that the type has invoker's rights

ub1

OCI_ATTR_NAME

A pointer to a string that is the type attribute name

OraText *

OCI_ATTR_PACKAGE_NAME

A string with the package name if the attribute is a package type.

OraText *

OCI_ATTR_SCHEMA_NAME

A string with the schema name where the type has been created

OraText *

OCI_ATTR_IS_FINAL_TYPE

Indicates that this is a final type

ub1

OCI_ATTR_IS_INSTANTIABL
E_TYPE

Indicates that this is an instantiable type

ub1

OCI_ATTR_IS_SUBTYPE

Indicates that this is a subtype

ub1

OCI_ATTR_SUPERTYPE_SCHE
MA_NAME

Name of the schema that contains the supertype

OraText *

OCI_ATTR_SUPERTYPE_NAME

Name of the supertype

OraText *

8-10

Chapter 8

Parameter Attributes

See Also:
OCIEnvCreate()

8.2.5 Type Attribute Attributes
Lists and describes the attributes when a parameter is for an attribute of a type.
Table 8-8 lists the attributes when a parameter is for an attribute of a type (type
OCI_PTYPE_TYPE_ATTR).
Table 8-8

Attributes of Type Attributes

Attribute

Description

Attribute
Data Type

OCI_ATTR_DATA_SIZE

The maximum size of the type attribute. This length is returned in bytes
and not characters for strings and raws. It returns 22 for NUMBERs.

OCI_ATTR_TYPECODE

Typecode. See Data Type Codes.

OCITypeCode

OCI_ATTR_DATA_TYPE

The data type of the type attribute. See Data Type Codes.

ub2

OCI_ATTR_NAME

A pointer to a string that is the type attribute name

OraText *

OCI_ATTR_PRECISION

The precision of numeric type attributes. If the precision is nonzero and
scale is -127, then it is a FLOAT; otherwise, it is a NUMBER(precision,
scale). When precision is 0, NUMBER(precision, scale) can be
represented simply as NUMBER.

ub2

ub1
for explicit
describe
sb2
for implicit
describe

OCI_ATTR_SCALE

The scale of numeric type attributes. If the precision is nonzero and scale
sb1
is -127, then it is a FLOAT; otherwise, it is a NUMBER(precision, scale).
When precision is 0, NUMBER(precision, scale) can be represented
simply as NUMBER.

OCI_ATTR_PACKAGE_NAME A string that is the package name of a type if it is a package type.

OraText *

OCI_ATTR_TYPE_NAME

A string that is the type name. The returned value contains the type name
OraText *
if the data type is SQLT_NTY or SQLT_REF. If the data type is SQLT_NTY, the
name of the named data type's type is returned. If the data type is
SQLT_REF, the type name of the named data type pointed to by the REF is
returned.

OCI_ATTR_SCHEMA_NAME

A string with the schema name under which the type has been created

OCI_ATTR_REF_TDO

Returns the in-memory REF of the TDO for the type, if the column type is
an object type. If space has not been reserved for the OCIRef, then it is
allocated implicitly in the cache. The caller can then pin the TDO with
OCIObjectPin().

OraText *
OCIRef *

8-11

Chapter 8

Parameter Attributes

Table 8-8

(Cont.) Attributes of Type Attributes

Attribute

Description

OCI_ATTR_CHARSET_ID

The character set ID, if the type attribute is of a string or character type

OCI_ATTR_CHARSET_FORM The character set form, if the type attribute is of a string or character type

Attribute
Data Type
ub2
ub1

OCI_ATTR_FSPRECISION

The fractional seconds precision of a datetime or interval

ub1

OCI_ATTR_LFPRECISION

The leading field precision of an interval

ub1

8.2.6 Type Method Attributes
Lists and dsescribes the attributes when a parameter is for a method of a type.
Table 8-9 lists the attributes when a parameter is for a method of a type (type
OCI_PTYPE_TYPE_METHOD).
Table 8-9

Attributes of Type Methods

Attribute

Description

Attribute
Data Type

OCI_ATTR_NAME

Name of method (procedure or function)

OCI_ATTR_ENCAPSULATION

Encapsulation level of the method (either OCI_TYPEENCAP_PRIVATE or
OCITypeEnca
OCI_TYPEENCAP_PUBLIC)
p

OCI_ATTR_LIST_ARGUMENTS

Argument list. See OCI_ATTR_LIST_ARGUMENTS Attribute, and
List Attributes.

OCI_ATTR_IS_CONSTRUCTOR

Indicates that method is a constructor

ub1

OCI_ATTR_IS_DESTRUCTOR

Indicates that method is a destructor

ub1

OCI_ATTR_IS_OPERATOR

Indicates that method is an operator

ub1

OCI_ATTR_IS_SELFISH

Indicates that method is selfish

ub1

OCI_ATTR_IS_MAP

Indicates that method is a map method

ub1

OCI_ATTR_IS_ORDER

Indicates that method is an order method

ub1

OCI_ATTR_IS_RNDS

Indicates that "Read No Data State" is set for method

ub1

OraText *

void *

8-12

Chapter 8

Parameter Attributes

Table 8-9

(Cont.) Attributes of Type Methods

Attribute

Description

Attribute
Data Type

OCI_ATTR_IS_RNPS

Indicates that "Read No Process State" is set for method

ub1

OCI_ATTR_IS_WNDS

Indicates that "Write No Data State" is set for method

ub1

OCI_ATTR_IS_WNPS

Indicates that "Write No Process State" is set for method

ub1

OCI_ATTR_IS_FINAL_METHOD

Indicates that this is a final method

ub1

OCI_ATTR_IS_INSTANTIABLE_ Indicates that this is an instantiable method
METHOD

ub1

OCI_ATTR_IS_OVERRIDING_ME Indicates that this is an overriding method
THOD

ub1

8.2.7 Collection Attributes
Lists and describes the attributes when a parameter is for a collection type.
Table 8-10 lists the attributes when a parameter is for a collection type (type
OCI_PTYPE_COLL).

Table 8-10

Attributes of Collection Types

Attribute

Description

Attribute
Data Type

OCI_ATTR_DATA_SIZE

The maximum size of the type attribute. This length is returned in bytes
and not characters for strings and raws. It returns 22 for NUMBERs.

OCI_ATTR_TYPECODE

Typecode. See Data Type Codes.

OCITypeCode

OCI_ATTR_DATA_TYPE

The data type of the type attribute. See Data Type Codes.

ub2

OCI_ATTR_NUM_ELEMS

The number of elements in an array. It is only valid for collections that are
arrays.

OCI_ATTR_NAME

A pointer to a string that is the type attribute name

OCI_ATTR_PRECISION

The precision of numeric type attributes. If the precision is nonzero and
scale is -127, then it is a FLOAT; otherwise, it is a NUMBER(precision,
scale). When precision is 0, NUMBER(precision, scale) can be
represented simply as NUMBER.

ub2

ub4
OraText *
ub1
for explicit
describe
sb2
for implicit
describe

8-13

Chapter 8

Parameter Attributes

Table 8-10

(Cont.) Attributes of Collection Types

Attribute

Description

Attribute
Data Type

OCI_ATTR_SCALE

The scale of numeric type attributes. If the precision is nonzero and scale
is -127, then it is a FLOAT; otherwise, it is a NUMBER(precision, scale).
When precision is 0, NUMBER(precision, scale) can be represented
simply as NUMBER.

OCI_ATTR_PACKAGE_NAM
E

A string that is the package name of a type if it is a package type.

OCI_ATTR_TYPE_NAME

A string that is the type name. The returned value contains the type name
if the data type is SQLT_NTY or SQLT_REF. If the data type is SQLT_NTY, the
name of the named data type's type is returned. If the data type is
SQLT_REF, the type name of the named data type pointed to by the REF is
returned.

OCI_ATTR_SCHEMA_NAME

A string with the schema name under which the type has been created

OCI_ATTR_REF_TDO

Returns the in-memory REF of the type descriptor object (TDO) for the
type, if the column type is an object type. If space has not been reserved
for the OCIRef, then it is allocated implicitly in the cache. The caller can
then pin the TDO with OCIObjectPin().

OCI_ATTR_CHARSET_ID

The character set ID, if the type attribute is of a string or character type

ub2

OCI_ATTR_CHARSET_FOR
M

The character set form, if the type attribute is of a string or character type

ub1

sb1

OraText *
OraText *

OraText *
OCIRef *

8.2.8 Synonym Attributes
Lists and describes the attributes when a parameter is for a synonym.
Table 8-11 lists the attributes when a parameter is for a synonym (type OCI_PTYPE_SYN).
Table 8-11

Attributes of Synonyms

Attribute

Description

Attribute Data Type

OCI_ATTR_OBJID

Object ID

ub4

OCI_ATTR_SCHEMA_NAME

A string containing the schema name of the
synonym translation

OCI_ATTR_NAME

A NULL-terminated string containing the object name
OraText *
of the synonym translation

OCI_ATTR_LINK

A NULL-terminated string containing the database
link name of the synonym translation

OraText *

OraText *

8-14

Chapter 8

Parameter Attributes

8.2.9 Sequence Attributes
Lists and describes the attributes when a parameter is for a sequence.
Table 8-12 lists the attributes when a parameter is for a sequence (type
OCI_PTYPE_SEQ).
Table 8-12

Attributes of Sequences

Attribute

Description

Attribute Data Type

OCI_ATTR_OBJID

Object ID

ub4

OCI_ATTR_MIN

Minimum value (in Oracle NUMBER format)

ub1

OCI_ATTR_MAX

Maximum value (in Oracle NUMBER format)

ub1

OCI_ATTR_INCR

Increment (in Oracle NUMBER format)

ub1

OCI_ATTR_CACHE

Number of sequence numbers cached; zero if
the sequence is not a cached sequence (in
Oracle NUMBER format)

OCI_ATTR_ORDER

Whether the sequence is ordered

ub1

OCI_ATTR_HW_MARK

High-water mark (in NUMBER format)

ub1

ub1

See Also:
OCINumber Examples

8.2.10 Column Attributes
Lists and describes the attributes when a parameter is for a column of a table or view.

Note:
For BINARY_FLOAT and BINARY_DOUBLE:
If OCIDescribeAny() is used to retrieve the column data type
(OCI_ATTR_DATA_TYPE) for BINARY_FLOAT or BINARY_DOUBLE columns in a table, it
returns the internal data type code.
The SQLT codes corresponding to the internal data type codes for
BINARY_FLOAT and BINARY_DOUBLE are SQLT_IBFLOAT and SQLT_IBDOUBLE.

8-15

Chapter 8

Parameter Attributes

The following table lists the attributes when a parameter is for a column of a table or
view (type OCI_PTYPE_COL).
Table 8-13

Attributes of Columns of Tables or Views

Attribute

Description

Attribut
e Data
Type

OCI_ATTR_CHAR_USED

Returns the type of length semantics of the column. Zero (0) means
byte-length semantics and 1 means character-length semantics. See
Character-Length Semantics Support in Describe Operations.

OCI_ATTR_CHAR_SIZE

Returns the column character length that is the number of characters
ub2
allowed in the column. It is the counterpart of OCI_ATTR_DATA_SIZE,
which gets the byte length. See Character-Length Semantics Support in
Describe Operations.

OCI_ATTR_COLLATION_ID

Returns the derived collation ID of the column. The
ub4 *
OCI_ATTR_COLLATION_ID attribute is valid only for select-list describes
based on a statement handle for a query and not for OCIDescribeAny()
describes. It is relevant only for select-list items of character data types.
For other data types the value is always OCI_COLLATION_NONE.
Table 8-14 describes the predefined constraints for a number of
commonly used collation IDs.

ub1

Note:
You can use the SQL built-in functions
NLS_COLLATION_ID and
NLS_COLLATION_NAME to map between
collation IDs returned for this attribute and
collation names used in SQL syntax.

See Also:
•
•

OCI_ATTR_COLLATION_ID
Oracle Database Globalization
Support Guide for information on how
this set collation influences query
processing

8-16

Chapter 8

Parameter Attributes

Table 8-13

(Cont.) Attributes of Columns of Tables or Views

Attribute

Description

OCI_ATTR_COL_PROPERTIES

Returns describe data regarding certain column properties. The
following are the flags available in OCI_ATTR_COL_PROPERTIES:
•
•

Attribut
e Data
Type
ub8

OCI_ATTR_COL_PROPERTY_IS_IDENTITY
OCI_ATTR_COL_PROPERTY_IS_GEN_ALWAYS

– 1 - represents it is ALWAYS GENERATED
– 0 - represents GENERATED BY DEFAULT
•
OCI_ATTR_COL_PROPERTY_IS_GEN_BY_DEF_ON_NULL
•
OCI_ATTR_COL_PROPERTY_IS_LPART
•
OCI_ATTR_COL_PROPERTY_IS_CONID
The following is a sample usage:
OCIAttrGet((dvoid*) mypard, (ub4) OCI_DTYPE_PARAM,
(dvoid*) &col_prop, (ub4 *) 0,(ub4) OCI_ATTR_COL_PROPERTIES,
(OCIError *) errhp ));
if(col_prop & OCI_ATTR_COL_PROPERTY_IS_IDENTITY)
printf("Identity Column \n");
if(col_prop & OCI_ATTR_COL_PROPERTY_IS_GEN_ALWAYS)
printf("Column is always generated\n");
if(col_prop & OCI_ATTR_COL_PROPERTY_IS_GEN_BY_DEF_ON_NULL)
printf("Column is generated by default on NULL\n");
if(col_prop & OCI_ATTR_COL_PROPERTY_IS_LPART)
printf("Column is an implicitly generated logical
partitioning column for container_map enabled objects\n");
if(col_prop & OCI_ATTR_COL_PROPERTY_IS_CONID)
printf("Column is a CON_ID column implicitly generated by
CONTAINERS() or is an ORIGIN_CON_ID column implicitly
generated for Extended Data Link\n");
See Oracle Database SQL Language Reference for more information
about the SQL syntax to specify these properties in an identity clause
for a column definition in the CREATE TABLE statement.
OCI_ATTR_INVISIBLE_COL

Returns whether a column is invisible or not. A value of TRUE indicates
the column is an invisible column. Otherwise, the value FALSE is
returned. See "Describing Each Column to Know Whether It Is an
Invisible Column" for an example.

OCI_ATTR_DATA_SIZE

The maximum size of the column. This length is returned in bytes and
not characters for strings and raws. It returns 22 for NUMBERs.

OCI_ATTR_DATA_TYPE

The data type of the column. See Data Type Codes.

OCI_ATTR_NAME

A pointer to a string that is the column name

ub1

ub2
ub2
OraText
*

8-17

Chapter 8

Parameter Attributes

Table 8-13

(Cont.) Attributes of Columns of Tables or Views

Attribute

Description

Attribut
e Data
Type

OCI_ATTR_PRECISION

The precision of numeric columns. If the precision is nonzero and scale
ub1
is -127, then it is a FLOAT; otherwise, it is a NUMBER(precision, scale).
When precision is 0, NUMBER(precision, scale) can be represented
for
simply as NUMBER.
explicit
describe
sb2
for
implicit
describe

OCI_ATTR_SCALE

The scale of numeric columns. If the precision is nonzero and scale is
-127, then it is a FLOAT; otherwise, it is a NUMBER(precision, scale).
When precision is 0, NUMBER(precision, scale) can be represented
simply as NUMBER.

OCI_ATTR_IS_NULL

Returns 0 if null values are not permitted for the column. Does not
return a correct value for a CUBE or ROLLUP operation.

OCI_ATTR_TYPE_NAME

Returns a string that is the type name. The returned value contains the
OraText
type name if the data type is SQLT_NTY or SQLT_REF. If the data type is
*
SQLT_NTY, the name of the named data type's type is returned. If the
data type is SQLT_REF, the type name of the named data type pointed to
by the REF is returned.

OCI_ATTR_SCHEMA_NAME

Returns a string with the schema name under which the type has been
created

OraText
*

OCI_ATTR_REF_TDO

The REF of the TDO for the type, if the column type is an object type

OCIRef *

OCI_ATTR_CHARSET_ID

The character set ID, if the column is of a string or character type

ub2

OCI_ATTR_CHARSET_FORM

The character set form, if the column is of a string or character type

ub1

sb1

ub1

Table 8-14 describes predefined constants for a number of commonly used collation
IDs, which can be returned for the attribute OCI_ATTR_COLLATION_ID. The constants are
listed with their values (in parenthesis) and the SQL names of the corresponding
collations.
Table 8-14

Predefined Collation IDs, Their ub4 Values (in parenthesis), and Their SQL Names

Collation ID (Value)

SQL Name

OCI_COLLATION_NONE (0)

Undefined collation; no collation has been specified.

OCI_COLLATION_NLS_COMP (16382)

USING_NLS_COMP

OCI_COLLATION_NLS_SORT (16381)

USING_NLS_SORT

OCI_COLLATION_NLS_SORT_CI (16380)

USING_NLS_SORT_CI

OCI_COLLATION_NLS_SORT_AI (16379)

USING_NLS_SORT_AI

8-18

Chapter 8

Parameter Attributes

Table 8-14
Names

(Cont.) Predefined Collation IDs, Their ub4 Values (in parenthesis), and Their SQL

Collation ID (Value)

SQL Name

OCI_COLLATION_NLS_SORT_CS (16378)

USING_NLS_SORT_CS

OCI_COLLATION_BINARY (16383)

BINARY

OCI_COLLATION_BINARY_CI (147455)

BINARY_CI

OCI_COLLATION_BINARY_AI (81919)

BINARY_AI

See Also:
OCIDescribeAny()

8.2.11 Argument and Result Attributes
Lists and describes the attributes when a parameter is for an argument of a procedure
or function.
Table 8-15 lists the attributes when a parameter is for an argument of a procedure or
function (type OCI_PTYPE_ARG), for a type method argument (type OCI_PTYPE_TYPE_ARG),
or for method results (type OCI_PTYPE_TYPE_RESULT).
Table 8-15

Attributes of Arguments and Results

Attribute

Description

OCI_ATTR_NAME

Returns a pointer to a string that is the argument name

OraText *

OCI_ATTR_POSITION

The position of the argument in the argument list. Always returns zero.

ub2

OCI_ATTR_TYPECODE

Typecode. See Data Type Codes.

OCITypeCode

OCI_ATTR_DATA_TYPE

The data type of the argument. See Data Type Codes.

ub2

OCI_ATTR_DATA_SIZE

The size of the data type of the argument. This length is returned in bytes
ub2
and not characters for strings and raws. It returns 22 for NUMBERs.

OCI_ATTR_PRECISION

The precision of numeric arguments. If the precision is nonzero and scale
is -127, then it is a FLOAT; otherwise, it is a NUMBER(precision, scale).
When precision is 0, NUMBER(precision, scale) can be represented
simply as NUMBER.

sb1 for
explicit
describe

The scale of numeric arguments. If the precision is nonzero and scale is
-127, then it is a FLOAT; otherwise, it is a NUMBER(precision, scale).
When precision is 0, NUMBER(precision, scale) can be represented
simply as NUMBER.

sb1

OCI_ATTR_SCALE

Attribute
Data Type

sb2 for
implicit
describe

8-19

Chapter 8

Parameter Attributes

Table 8-15

(Cont.) Attributes of Arguments and Results

Attribute

Description

OCI_ATTR_LEVEL

The data type levels. This attribute always returns zero.

OCI_ATTR_HAS_DEFAULT Indicates whether an argument has a default
OCI_ATTR_LIST_ARGUME The list of arguments at the next level (when the argument is of a record
or table type)
NTS
Indicates the argument mode:

OCI_ATTR_IOMODE

0 is IN (OCI_TYPEPARAM_IN),

Attribute
Data Type
ub2
ub1
void *
OCITypeParam
Mode

1 is OUT (OCI_TYPEPARAM_OUT),
2 is IN/OUT (OCI_TYPEPARAM_INOUT)
OCI_ATTR_RADIX

Returns a radix (if number type)

ub1

OCI_ATTR_IS_NULL

Returns 0 if null values are not permitted for the column

ub1

OCI_ATTR_TYPE_NAME

Returns a string that is the type name or the package name for package
local types. The returned value contains the type name if the data type is
SQLT_NTY or SQLT_REF. If the data type is SQLT_NTY, the name of the
named data type's type is returned. If the data type is SQLT_REF, the type
name of the named data type pointed to by the REF is returned.

OCI_ATTR_SCHEMA_NAME For SQLT_NTY or SQLT_REF, returns a string with the schema name under
which the type was created, or under which the package was created for
package local types

OraText *

OraText *

OCI_ATTR_SUB_NAME

For SQLT_NTY or SQLT_REF, returns a string with the type name, for
package local types

OCI_ATTR_LINK

For SQLT_NTY or SQLT_REF, returns a string with the database link name of
OraText *
the database on which the type exists. This can happen only for package
local types, when the package is remote.

OCI_ATTR_REF_TDO

Returns the REF of the type descriptor object (TDO) for the type, if the
argument type is an object

OCIRef *

OCI_ATTR_CHARSET_ID

Returns the character set ID if the argument is of a string or character
type

ub2

OCI_ATTR_CHARSET_FOR Returns the character set form if the argument is of a string or character
type
M

OraText *

ub1

8.2.12 List Attributes
Lists and describes the attributes when the parameter is for a list of columns,
arguments, and subprograms, or fields of a package record type.
When a parameter is for a list of columns, arguments, and subprograms, or fields of a
package record type (type OCI_PTYPE_LIST), it has the type-specific attributes and
handles (parameters) shown in Table 8-16.
The list has an OCI_ATTR_LTYPE attribute that designates the list type. Table 8-16 lists
the possible values and their lower bounds when traversing the list.

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Chapter 8

Parameter Attributes

Table 8-16

List Attributes

List Attribute

Description

Lower Bound

OCI_LTYPE_COLUMN

Column list

1

OCI_LTYPE_ARG_PROC

Procedure argument list

1

OCI_LTYPE_ARG_FUNC

Function argument list

0

OCI_LTYPE_SUBPRG

Subprogram list

0

OCI_LTYPE_TYPE_ATTR

Type attribute list

1

OCI_LTYPE_TYPE_METHOD

Type method list

1

OCI_LTYPE_TYPE_ARG_PROC

Type method without result argument list

0

OCI_LTYPE_TYPE_ARG_FUNC

Type method without result argument list

1

OCI_LTYPE_SCH_OBJ

Object list within a schema

0

OCI_LTYPE_DB_SCH

Schema list within a database

0

The list has an OCI_ATTR_NUM_PARAMS attribute, which tells the number of elements in the
list.
Each list has LowerBound ... OCI_ATTR_NUM_PARAMS parameters. LowerBound is the value in
the Lower Bound column of Table 8-16. For a function argument list, position 0 has a
parameter for the return value (type OCI_PTYPE_ARG).

8.2.13 Schema Attributes
Lists and describes the attributes when a parameter is for a schema type.
Table 8-17 lists the attributes when a parameter is for a schema type (type
OCI_PTYPE_SCHEMA).

Table 8-17

Attributes Specific to Schemas

Attribute

Description

Attribute Data Type

OCI_ATTR_LIST_OBJECTS

List of objects in the schema

OCIParam *

8.2.14 Database Attributes
Lists and describes the attributes when a parameter is for a database type.
Table 8-18 lists the attributes when a parameter is for a database type (type
OCI_PTYPE_DATABASE).

Table 8-18

Attributes Specific to Databases

Attribute

Description

Attribute Data Type

OCI_ATTR_VERSION

Database version

OraText *

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Chapter 8

Parameter Attributes

Table 8-18

(Cont.) Attributes Specific to Databases

Attribute

Description

Attribute Data Type

OCI_ATTR_CHARSET_ID

Database character set ID from the server
handle

ub2

OCI_ATTR_NCHARSET_ID

Database national character set ID from
the server handle

ub2

OCI_ATTR_LIST_SCHEMAS

List of schemas (type OCI_PTYPE_SCHEMA)
in the database

ub1

OCI_ATTR_MAX_PROC_LEN

Maximum length of a procedure name

ub4

OCI_ATTR_MAX_COLUMN_LEN

Maximum length of a column name

ub4

OCI_ATTR_CURSOR_COMMIT_BEHAVIOR

How a COMMIT operation affects cursors
and prepared statements in the database.
Values are:

ub1

OCI_CURSOR_OPEN - Preserve cursor state
as before the commit operation.
OCI_CURSOR_CLOSED - Cursors are closed
on COMMIT, but the application can still
reexecute the statement without preparing
it again.
OCI_ATTR_MAX_CATALOG_NAMELEN

Maximum length of a catalog (database)
name

OCI_ATTR_CATALOG_LOCATION

Position of the catalog in a qualified table.
ub1
Values are OCI_CL_START and OCI_CL_END.

OCI_ATTR_SAVEPOINT_SUPPORT

Does database support savepoints?
Values are OCI_SP_SUPPORTED and
OCI_SP_UNSUPPORTED.

OCI_ATTR_NOWAIT_SUPPORT

Does database support the nowait clause?
ub1
Values are OCI_NW_SUPPORTED and
OCI_NW_UNSUPPORTED.

OCI_ATTR_AUTOCOMMIT_DDL

Is autocommit mode required for DDL
statements? Values are OCI_AC_DDL and
OCI_NO_AC_DDL.

OCI_ATTR_LOCKING_MODE

Locking mode for the database. Values are
ub1
OCI_LOCK_IMMEDIATE and
OCI_LOCK_DELAYED.

ub1

ub1

ub1

8.2.15 Rule Attributes
Lists and describes the attributes when a parameter is for a rule.
Table 8-19 lists the attributes when a parameter is for a rule (type OCI_PTYPE_RULE).

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Chapter 8

Parameter Attributes

Table 8-19

Attributes Specific to Rules

Attribute

Description

Attribute Data Type

OCI_ATTR_CONDITION

Rule condition

OraText *

OCI_ATTR_EVAL_CONTEXT_OWNER

Owner name of the evaluation context
associated with the rule, if any

OraText *

OCI_ATTR_EVAL_CONTEXT_NAME

Object name of the evaluation context
associated with the rule, if any

OraText *

OCI_ATTR_COMMENT

Comment associated with the rule, if any

OCI_ATTR_LIST_ACTION_CONTEXT

List of name-value pairs in the action context
(type OCI_PTYPE_LIST)

OraText *
void *

8.2.16 Rule Set Attributes
Lists and describes the attributes when a parameter is for a rule set.
Table 8-20 lists the attributes when a parameter is for a rule set (type
OCI_PTYPE_RULE_SET).
Table 8-20

Attributes Specific to Rule Sets

Attribute

Description

Attribute Data Type

OCI_ATTR_EVAL_CONTEXT_OWNER

Owner name of the evaluation context
associated with the rule set, if any

OraText *

OCI_ATTR_EVAL_CONTEXT_NAME

Object name of the evaluation context
associated with the rule set, if any

OraText *

OCI_ATTR_COMMENT

Comment associated with the rule set, if any

OCI_ATTR_LIST_RULES

List of rules in the rule set (type
OCI_PTYPE_LIST)

OraText *
void *

8.2.17 Evaluation Context Attributes
Lists and describes the attributes when a parameter is for an evaluation context.
Table 8-21 lists the attributes when a parameter is for an evaluation context (type
OCI_PTYPE_EVALUATION_CONTEXT).

Table 8-21

Attributes Specific to Evaluation Contexts

Attribute

Description

Attribute Data Type

OCI_ATTR_EVALUATION_FUNCTION

Evaluation function associated with the
evaluation context, if any

OraText *

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Chapter 8

Parameter Attributes

Table 8-21

(Cont.) Attributes Specific to Evaluation Contexts

Attribute

Description

Attribute Data Type

OCI_ATTR_COMMENT

Comment associated with the evaluation
context, if any

OraText *

OCI_ATTR_LIST_TABLE_ALIASES

List of table aliases in the evaluation context
(type OCI_PTYPE_LIST)

void *

OCI_ATTR_LIST_VARIABLE_TYPES

List of variable types in the evaluation context
(type OCI_PTYPE_LIST)

void *

8.2.18 Table Alias Attributes
Lists and describes the attributes when a parameter is for a table alias.
Table 8-22 lists the attributes when a parameter is for a table alias (type
OCI_PTYPE_TABLE_ALIAS).
Table 8-22

Attributes Specific to Table Aliases

Attribute

Description

Attribute Data Type

OCI_ATTR_NAME

Table alias name

OraText *

OCI_ATTR_TABLE_NAME

Table name associated with the alias

OraText *

8.2.19 Variable Type Attributes
Lists and describes the attributes when a parameter is for a variable.
Table 8-23 lists the attributes when a parameter is for a variable (type
OCI_PTYPE_VARIABLE_TYPE).

Table 8-23

Attributes Specific to Variable Types

Attribute

Description

Attribute Data
Type

OCI_ATTR_NAME

Variable name

OraText *

OCI_ATTR_TYPE

Variable type

OraText *

OCI_ATTR_VAR_VALUE_FUNCTION

Variable value function associated with the
variable, if any

OraText *

OCI_ATTR_VAR_METHOD_FUNCTION

Variable method function associated with the
variable, if any

OraText *

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Character-Length Semantics Support in Describe Operations

8.2.20 Name Value Attributes
Lists and describes the attributes when a parameter is for a name-value pair.
Table 8-24 lists the attributes when a parameter is for a name-value pair (type
OCI_PTYPE_NAME_VALUE).
Table 8-24

Attributes Specific to Name-Value Pair

Attribute

Description

Attribute Data Type

OCI_ATTR_NAME

Name

OraText *

OCI_ATTR_VALUE

Value

OCIAnyData*

8.3 Character-Length Semantics Support in Describe
Operations
Query and column information are supported with character-length semantics.
Since release Oracle9i, query and column information are supported with characterlength semantics.
The following attributes of describe handles support character-length semantics:
•

OCI_ATTR_CHAR_SIZE gets the column character length, which is the number of
characters allowed in the column. It is the counterpart of OCI_ATTR_DATA_SIZE, which

gets the byte length.
•

Calling OCIAttrGet() with attribute OCI_ATTR_CHAR_SIZE or OCI_ATTR_DATA_SIZE does
not return data on stored procedure parameters, because stored procedure
parameters are not bounded.

•

OCI_ATTR_CHAR_USED gets the type of length semantics of the column. Zero (0)

means byte-length semantics and 1 means character-length semantics.
An application can describe a select-list query either implicitly or explicitly through
OCIStmtExecute(). Other schema elements must be described explicitly through
OCIDescribeAny().
This section includes the following topics:
•

Implicit Describing

•

Explicit Describing

See Also:
•

OCIStmtExecute()

•

OCIDescribeAny()

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Chapter 8

Character-Length Semantics Support in Describe Operations

8.3.1 Implicit Describing
If the database column was created using character-length semantics, then the implicit
describe information contains the character length, the byte length, and a flag
indicating how the database column was created.
OCI_ATTR_CHAR_SIZE is the character length of the column or expression. The
OCI_ATTR_CHAR_USED flag is 1 in this case, indicating that the column or expression was

created with character-length semantics.
The OCI_ATTR_DATA_SIZE value is always large enough to hold all the data, as many as
OCI_ATTR_CHAR_SIZE number of characters. The OCI_ATTR_DATA_SIZE is usually set to
(OCI_ATTR_CHAR_SIZE)*(the client's maximum number of bytes) for each character value.
If the database column was created with byte-length semantics, then for the implicit
describe (it behaves exactly as it does before release 9.0) the OCI_ATTR_DATA_SIZE
value returned is (column's byte length)*(the maximum conversion ratio between the
client and server's character set). That is, the column byte length divided by the
server's maximum number of bytes for each character multiplied by the client's
maximum number of bytes for each character. The OCI_ATTR_CHAR_USED value is 0 and
the OCI_ATTR_CHAR_SIZE value is set to the same value as OCI_ATTR_DATA_SIZE.

8.3.2 Explicit Describing
Explicit describes of tables have three attributes: OCI_ATTR_DATA_SIZE,
OCI_ATTR_CHAR_SIZE, and OCI_ATTR_CHAR_USED.

Explicit describes of tables have the following attributes:
•

OCI_ATTR_DATA_SIZE gets the column's size in bytes, as it appears in the server

•

OCI_ATTR_CHAR_SIZE indicates the length of the column in characters

•

OCI_ATTR_CHAR_USED, is a flag that indicates how the column was created, as

described previously in terms of the type of length semantics of the column
When inserting, if the OCI_ATTR_CHAR_USED flag is set, you can set the
OCI_ATTR_MAXCHAR_SIZE in the bind handle to the value returned by OCI_ATTR_CHAR_SIZE
in the parameter handle. This prevents you from violating the size constraint for the
column.
This section includes the following topic: Client and Server Compatibility Issues for
Describing.

See Also:
IN Binds

8.3.2.1 Client and Server Compatibility Issues for Describing
Character-length semantics depends on the release of the server or client. It is best
described when both server and client are Oracle9i or later. Otherwise, compatibility
issues as described result.

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Examples Using OCIDescribeAny()

When an Oracle9i or later client talks to an Oracle8i or earlier server, it behaves as if
the database is only using byte-length semantics.
When an Oracle8i or earlier client talks to a Oracle9i or later server, the attributes
OCI_ATTR_CHAR_SIZE and OCI_ATTR_CHAR_USED are not available on the client side.

In both cases, the character-length semantics cannot be described when either the
server or client has an Oracle8i or earlier software release.

8.4 Examples Using OCIDescribeAny()
The following examples demonstrate the use of OCIDescribeAny() for describing
different types of schema objects.
For a more detailed code sample, see the demonstration program cdemodsa.c included
with your Oracle Database installation.
•

Retrieving Column Data Types for a Table

•

Describing the Stored Procedure

•

Retrieving Attributes of an Object Type

•

Retrieving the Collection Element's Data Type of a Named Collection Type

•

Describing with Character-Length Semantics

•

Describing Each Column to Know Whether It Is an Invisible Column

See Also:
•

OCI Demonstration Programs for additional information about the
demonstration programs

•

OCIDescribeAny()

8.4.1 Retrieving Column Data Types for a Table
Illustrates the use of an explicit describe that retrieves the column data types for a
table.
Example 8-2 illustrates the use of an explicit describe that retrieves the column data
types for a table.
Example 8-2
Table

Using an Explicit Describe to Retrieve Column Data Types for a

...
int i=0;
text objptr[] = "EMPLOYEES"; /* the name of a table to be described */
ub2
numcols, col_width;
ub1
char_semantics;
ub2 coltyp;
ub4 objp_len = (ub4) strlen((char *)objptr);
OCIParam *parmh = (OCIParam *) 0;
/* parameter handle */
OCIParam *collsthd = (OCIParam *) 0;
/* handle to list of columns */

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Chapter 8

Examples Using OCIDescribeAny()

OCIParam *colhd = (OCIParam *) 0;
OCIDescribe *dschp = (OCIDescribe *)0;

/* column handle */
/* describe handle */

OCIHandleAlloc((void *)envhp, (void **)&dschp,
(ub4)OCI_HTYPE_DESCRIBE, (size_t)0, (void **)0);
/* get the describe handle for the table */
if (OCIDescribeAny(svch, errh, (void *)objptr, objp_len, OCI_OTYPE_NAME, 0,
OCI_PTYPE_TABLE, dschp))
return OCI_ERROR;
/* get the parameter handle */
if (OCIAttrGet((void *)dschp, OCI_HTYPE_DESCRIBE, (void *)&parmh, (ub4 *)0,
OCI_ATTR_PARAM, errh))
return OCI_ERROR;
/* The type information of the object, in this case, OCI_PTYPE_TABLE,
is obtained from the parameter descriptor returned by the OCIAttrGet(). */
/* get the number of columns in the table */
numcols = 0;
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, (void *)&numcols, (ub4 *)0,
OCI_ATTR_NUM_COLS, errh))
return OCI_ERROR;
/* get the handle to the column list of the table */
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, (void *)&collsthd, (ub4 *)0,
OCI_ATTR_LIST_COLUMNS, errh)==OCI_NO_DATA)
return OCI_ERROR;
/* go through the column list and retrieve the data type of each column,
and then recursively describe column types. */
for (i = 1; i <= numcols; i++)
{
/* get parameter for column i */
if (OCIParamGet((void *)collsthd, OCI_DTYPE_PARAM, errh, (void **)&colhd,
(ub4)i))
return OCI_ERROR;
/* for example, get data type for ith column */
coltyp = 0;
if (OCIAttrGet((void *)colhd, OCI_DTYPE_PARAM, (void *)&coltyp, (ub4 *)0,
OCI_ATTR_DATA_TYPE, errh))
return OCI_ERROR;
/* Retrieve the length semantics for the column */
char_semantics = 0;
OCIAttrGet((void*) colhd, (ub4) OCI_DTYPE_PARAM,
(void*) &char_semantics,(ub4 *) 0, (ub4) OCI_ATTR_CHAR_USED,
(OCIError *) errh);
col_width = 0;
if (char_semantics)
/* Retrieve the column width in characters */
OCIAttrGet((void*) colhd, (ub4) OCI_DTYPE_PARAM,
(void*) &col_width, (ub4 *) 0, (ub4) OCI_ATTR_CHAR_SIZE,
(OCIError *) errh);
else
/* Retrieve the column width in bytes */
OCIAttrGet((void*) colhd, (ub4) OCI_DTYPE_PARAM,
(void*) &col_width,(ub4 *) 0, (ub4) OCI_ATTR_DATA_SIZE,

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Chapter 8

Examples Using OCIDescribeAny()

(OCIError *) errh);
}
if (dschp)
OCIHandleFree((void *) dschp, OCI_HTYPE_DESCRIBE);
...

8.4.2 Describing the Stored Procedure
The steps required to describe type methods (also divided into functions and
procedures) are identical to those of regular PL/SQL functions and procedures.
The difference between a procedure and a function is that the latter has a return type
at position 0 in the argument list, whereas the former has no argument associated with
position 0 in the argument list. Note that procedures and functions can take the default
types of objects as arguments. Consider the following procedure:
P1 (arg1 emp.sal%type, arg2 emp%rowtype)

In Example 8-3, assume that each row in emp table has two columns:
name(VARCHAR2(20)) and sal(NUMBER). In the argument list for P1, there are two
arguments (arg1 and arg2 at positions 1 and 2, respectively) at level 0 and arguments
(name and sal at positions 1 and 2, respectively) at level 1. Description of P1 returns the
number of arguments as two while returning the higher level (> 0) arguments as
attributes of the 0 zero level arguments.
Example 8-3

Describing the Stored Procedure

...
int i = 0, j = 0;
text objptr[] = "add_job_history"; /* the name of a procedure to be described */
ub4 objp_len = (ub4)strlen((char *)objptr);
ub2 numargs = 0, numargs1, pos, level;
text *name, *name1;
ub4 namelen, namelen1;
OCIParam *parmh = (OCIParam *) 0;
/* parameter handle */
OCIParam *arglst = (OCIParam *) 0;
/* list of args */
OCIParam *arg = (OCIParam *) 0;
/* argument handle */
OCIParam *arglst1 = (OCIParam *) 0;
/* list of args */
OCIParam *arg1 = (OCIParam *) 0;
/* argument handle */
OCIDescribe *dschp = (OCIDescribe *)0;
/* describe handle */
OCIHandleAlloc((void *)envhp, (void **)&dschp,
(ub4)OCI_HTYPE_DESCRIBE, (size_t)0, (void **)0);
/* get the describe handle for the procedure */
if (OCIDescribeAny(svch, errh, (void *)objptr, objp_len, OCI_OTYPE_NAME, 0,
OCI_PTYPE_PROC, dschp))
return OCI_ERROR;
/* get the parameter handle */
if (OCIAttrGet((void *)dschp, OCI_HTYPE_DESCRIBE, (void *)&parmh, (ub4 *)0,
OCI_ATTR_PARAM, errh))
return OCI_ERROR;
/* Get the number of arguments and the arg list */
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, (void *)&arglst,
(ub4 *)0, OCI_ATTR_LIST_ARGUMENTS, errh))
return OCI_ERROR;

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Examples Using OCIDescribeAny()

if (OCIAttrGet((void *)arglst, OCI_DTYPE_PARAM, (void *)&numargs, (ub4 *)0,
OCI_ATTR_NUM_PARAMS, errh))
return OCI_ERROR;
/* For a procedure, you begin with i = 1; for a
function, you begin with i = 0. */
for (i = 1; i <= numargs; i++) {
OCIParamGet ((void *)arglst, OCI_DTYPE_PARAM, errh, (void **)&arg, (ub4)i);
namelen = 0;
OCIAttrGet((void *)arg, OCI_DTYPE_PARAM, (void *)&name, (ub4 *)&namelen,
OCI_ATTR_NAME, errh);
/* to print the attributes of the argument of type record
(arguments at the next level), traverse the argument list */
OCIAttrGet((void *)arg, OCI_DTYPE_PARAM, (void *)&arglst1, (ub4 *)0,
OCI_ATTR_LIST_ARGUMENTS, errh);
/* check if the current argument is a record. For arg1 in the procedure
arglst1 is NULL. */
if (arglst1) {
numargs1 = 0;
OCIAttrGet((void *)arglst1, OCI_DTYPE_PARAM, (void *)&numargs1, (ub4 *)0,
OCI_ATTR_NUM_PARAMS, errh);
/* Note that for both functions and procedures,the next higher level
arguments start from index 1. For arg2 in the procedure, the number of
arguments at the level 1 would be 2 */
for (j = 1; j <= numargs1; j++) {
OCIParamGet((void *)arglst1, OCI_DTYPE_PARAM, errh, (void **)&arg1,
(ub4)j);
namelen1 = 0;
OCIAttrGet((void *)arg1, OCI_DTYPE_PARAM, (void *)&name1, (ub4 *)&namelen1,
OCI_ATTR_NAME, errh);
}
}
}
if (dschp)
OCIHandleFree((void *) dschp, OCI_HTYPE_DESCRIBE);
...

8.4.3 Retrieving Attributes of an Object Type
Illustrates the use of an explicit describe on a named object type.
Example 8-4 illustrates the use of an explicit describe on a named object type. It
illustrates how you can describe an object by its name or by its object reference
(OCIRef). The following code fragment attempts to retrieve the data type value of each
of the object type's attributes.
Example 8-4

Using an Explicit Describe on a Named Object Type

...
int i = 0;
text type_name[] = "inventory_typ";
ub4 type_name_len = (ub4)strlen((char *)type_name);

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Examples Using OCIDescribeAny()

OCIRef *type_ref = (OCIRef *) 0;
ub2 numattrs = 0, describe_by_name = 1;
ub2 datatype = 0;
OCITypeCode typecode = 0;
OCIDescribe *dschp = (OCIDescribe *) 0;
OCIParam *parmh = (OCIParam *) 0;
OCIParam *attrlsthd = (OCIParam *) 0;
OCIParam *attrhd = (OCIParam *) 0;

/* describe handle */
/* parameter handle */
/* handle to list of attrs */
/* attribute handle */

/* allocate describe handle */
if (OCIHandleAlloc((void *)envh, (void **)&dschp,
(ub4)OCI_HTYPE_DESCRIBE, (size_t)0, (void **)0))
return OCI_ERROR;
/* get the describe handle for the type */
if (describe_by_name) {
if (OCIDescribeAny(svch, errh, (void *)type_name, type_name_len,
OCI_OTYPE_NAME, 0, OCI_PTYPE_TYPE, dschp))
return OCI_ERROR;
}
else {
/* get ref to type using OCIAttrGet */
/* get the describe handle for the type */
if (OCIDescribeAny(svch, errh, (void*)type_ref, 0, OCI_OTYPE_REF,
0, OCI_PTYPE_TYPE, dschp))
return OCI_ERROR;
}
/* get the parameter handle */
if (OCIAttrGet((void *)dschp, OCI_HTYPE_DESCRIBE, (void *)&parmh, (ub4 *)0,
OCI_ATTR_PARAM, errh))
return OCI_ERROR;
/* The type information of the object, in this case, OCI_PTYPE_TYPE, is
obtained from the parameter descriptor returned by OCIAttrGet */
/* get the number of attributes in the type */
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, (void *)&numattrs, (ub4 *)0,
OCI_ATTR_NUM_TYPE_ATTRS, errh))
return OCI_ERROR;
/* get the handle to the attribute list of the type */
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, (void *)&attrlsthd, (ub4 *)0,
OCI_ATTR_LIST_TYPE_ATTRS, errh))
return OCI_ERROR;
/* go through the attribute list and retrieve the data type of each attribute,
and then recursively describe attribute types. */
for (i = 1; i <= numattrs; i++)
{
/* get parameter for attribute i */
if (OCIParamGet((void *)attrlsthd, OCI_DTYPE_PARAM, errh, (void **)&attrhd, i))
return OCI_ERROR;
/* for example, get data type and typecode for attribute; note that
OCI_ATTR_DATA_TYPE returns the SQLT code, whereas OCI_ATTR_TYPECODE returns the
Oracle Type System typecode. */
datatype = 0;

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Chapter 8

Examples Using OCIDescribeAny()

if (OCIAttrGet((void *)attrhd, OCI_DTYPE_PARAM, (void *)&datatype, (ub4 *)0,
OCI_ATTR_DATA_TYPE,errh))
return OCI_ERROR;
typecode = 0;
if (OCIAttrGet((void *)attrhd, OCI_DTYPE_PARAM,(void *)&typecode, (ub4 *)0,
OCI_ATTR_TYPECODE, errh))
return OCI_ERROR;
/* if attribute is an object type, recursively describe it */
if (typecode == OCI_TYPECODE_OBJECT)
{
OCIRef *attr_type_ref;
OCIDescribe *nested_dschp;
/* allocate describe handle */
if (OCIHandleAlloc((void *)envh,(void**)&nested_dschp,
(ub4)OCI_HTYPE_DESCRIBE,(size_t)0, (void **)0))
return OCI_ERROR;
if (OCIAttrGet((void *)attrhd, OCI_DTYPE_PARAM,
(void *)&attr_type_ref, (ub4 *)0, OCI_ATTR_REF_TDO,errh))
return OCI_ERROR;
OCIDescribeAny(svch, errh,(void*)attr_type_ref, 0,
OCI_OTYPE_REF, 0, OCI_PTYPE_TYPE, nested_dschp);
/* go on describing the attribute type... */
}
}
if (dschp)
OCIHandleFree((void *) dschp, OCI_HTYPE_DESCRIBE);
...

8.4.4 Retrieving the Collection Element's Data Type of a Named
Collection Type
Illustrates the use of an explicit describe on a named collection type.
Example 8-5 illustrates the use of an explicit describe on a named collection type.
Example 8-5

Using an Explicit Describe on a Named Collection Type

text type_name[] = "phone_list_typ";
ub4 type_name_len = (ub4) strlen((char *)type_name);
OCIRef *type_ref = (OCIRef *) 0;
ub2 describe_by_name = 1;
ub4 num_elements = 0;
OCITypeCode typecode = 0, collection_typecode = 0, element_typecode = 0;
void *collection_element_parmh = (void *) 0;
OCIDescribe *dschp = (OCIDescribe *) 0;
/* describe handle */
OCIParam *parmh = (OCIParam *) 0;
/* parameter handle */
/* allocate describe handle */
if (OCIHandleAlloc((void *)envh, (void **)&dschp,
(ub4)OCI_HTYPE_DESCRIBE, (size_t)0, (void **)0))
return OCI_ERROR;
/* get the describe handle for the type */
if (describe_by_name) {

8-32

Chapter 8

Examples Using OCIDescribeAny()

if (OCIDescribeAny(svch, errh, (void *)type_name, type_name_len,
OCI_OTYPE_NAME, 0, OCI_PTYPE_TYPE, dschp))
return OCI_ERROR;
}
else {
/* get ref to type using OCIAttrGet */
/* get the describe handle for the type */
if (OCIDescribeAny(svch, errh, (void*)type_ref, 0, OCI_OTYPE_REF,
0, OCI_PTYPE_TYPE, dschp))
return OCI_ERROR;
}
/* get the parameter handle */
if (OCIAttrGet((void *)dschp, OCI_HTYPE_DESCRIBE, (void *)&parmh, (ub4 *)0,
OCI_ATTR_PARAM, errh))
return OCI_ERROR;
/* get the Oracle Type System type code of the type to determine that this is a
collection type */
typecode = 0;
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM,(void *)&typecode, (ub4 *)0,
OCI_ATTR_TYPECODE, errh))
return OCI_ERROR;
/* if typecode is OCI_TYPECODE_NAMEDCOLLECTION,
proceed to describe collection element */
if (typecode == OCI_TYPECODE_NAMEDCOLLECTION)
{
/* get the collection's type: OCI_TYPECODE_VARRAY or OCI_TYPECODE_TABLE */
collection_typecode = 0;
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, (void *)&collection_typecode,
(ub4 *)0,
OCI_ATTR_COLLECTION_TYPECODE, errh))
return OCI_ERROR;
/* get the collection element; you MUST use this to further retrieve information
about the collection's element */
if (OCIAttrGet((void *)parmh, OCI_DTYPE_PARAM, &collection_element_parmh,
(ub4 *)0,
OCI_ATTR_COLLECTION_ELEMENT, errh))
return OCI_ERROR;
/* get the number of elements if collection is a VARRAY; not valid for nested
tables */
if (collection_typecode == OCI_TYPECODE_VARRAY) {
if (OCIAttrGet((void *)collection_element_parmh, OCI_DTYPE_PARAM,
(void *)&num_elements, (ub4 *)0, OCI_ATTR_NUM_ELEMS, errh))
return OCI_ERROR;
}
/* now use the collection_element parameter handle to retrieve information about
the collection element */
element_typecode = 0;
if (OCIAttrGet((void *)collection_element_parmh, OCI_DTYPE_PARAM,
(void *)&element_typecode, (ub4 *)0, OCI_ATTR_TYPECODE, errh))
return OCI_ERROR;
/* do the same to describe additional collection element information; this is
very similar to describing type attributes */
}
if (dschp)

8-33

Chapter 8

Examples Using OCIDescribeAny()

OCIHandleFree((void *) dschp, OCI_HTYPE_DESCRIBE);
...

8.4.5 Describing with Character-Length Semantics
Shows a loop that retrieves the column names and data types corresponding to a
query following query execution.
Example 8-6 shows a loop that retrieves the column names and data types
corresponding to a query following query execution. The query was associated with
the statement handle by a prior call to OCIStmtPrepare2().
Example 8-6 Using a Parameter Descriptor to Retrieve the Data Types, Column
Names, and Character-Length Semantics
...
OCIParam
ub2
text
ub4
ub2
sb4

*mypard = (OCIParam *) 0;
dtype;
*col_name;
counter, col_name_len, char_semantics;
col_width;
parm_status;

text *sqlstmt = (text *)"SELECT * FROM employees WHERE employee_id = 100";
checkerr(errhp, OCIStmtPrepare2(svchp, &stmthp, errhp, (OraText *)sqlstmt,
(ub4)strlen((char *)sqlstmt), NULL, 0,
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, 0, 0, (OCISnapshot *)0,
(OCISnapshot *)0, OCI_DEFAULT));
/* Request a parameter descriptor for position 1 in the select list */
counter = 1;
parm_status = OCIParamGet((void *)stmthp, OCI_HTYPE_STMT, errhp,
(void **)&mypard, (ub4) counter);
/* Loop only if a descriptor was successfully retrieved for
current position, starting at 1 */
while (parm_status == OCI_SUCCESS) {
/* Retrieve the data type attribute */
checkerr(errhp, OCIAttrGet((void*) mypard, (ub4) OCI_DTYPE_PARAM,
(void*) &dtype,(ub4 *) 0, (ub4) OCI_ATTR_DATA_TYPE,
(OCIError *) errhp ));
/* Retrieve the column name attribute */
col_name_len = 0;
checkerr(errhp, OCIAttrGet((void*) mypard, (ub4) OCI_DTYPE_PARAM,
(void**) &col_name, (ub4 *) &col_name_len, (ub4) OCI_ATTR_NAME,
(OCIError *) errhp ));
/* Retrieve the length semantics for the column */
char_semantics = 0;
checkerr(errhp, OCIAttrGet((void*) mypard, (ub4) OCI_DTYPE_PARAM,
(void*) &char_semantics,(ub4 *) 0, (ub4) OCI_ATTR_CHAR_USED,
(OCIError *) errhp ));
col_width = 0;
if (char_semantics)
/* Retrieve the column width in characters */
checkerr(errhp, OCIAttrGet((void*) mypard, (ub4) OCI_DTYPE_PARAM,
(void*) &col_width, (ub4 *) 0, (ub4) OCI_ATTR_CHAR_SIZE,
(OCIError *) errhp ));
else
/* Retrieve the column width in bytes */

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Chapter 8

Examples Using OCIDescribeAny()

checkerr(errhp, OCIAttrGet((void*) mypard, (ub4) OCI_DTYPE_PARAM,
(void*) &col_width,(ub4 *) 0, (ub4) OCI_ATTR_DATA_SIZE,
(OCIError *) errhp ));
/* increment counter and get next descriptor, if there is one */
counter++;
parm_status = OCIParamGet((void *)stmthp, OCI_HTYPE_STMT, errhp,
(void **)&mypard, (ub4) counter);
} /* while */
...

8.4.6 Describing Each Column to Know Whether It Is an Invisible
Column
Illustrates the use of invisible column properties and checking each column to
determine if it is an invisible column.
The following code example illustrates the use of invisible column properties and
checking each column to determine if it is an invisible column. See the
OCI_ATTR_INVISIBLE_COL attribute description in the table in Column Attributes for more
information.
Example 8-7

Checking for Invisible Columns

.....
.....
checkerr(errhp, OCIHandleAlloc((dvoid *) envhp, (dvoid **) &dschp,
(ub4) OCI_HTYPE_DESCRIBE,
(size_t) 0, (dvoid **) 0));
/* Set the invisible column attribute to get the invisible column(s). */
checkerr(errhp, OCIAttrSet(dschp, OCI_HTYPE_DESCRIBE, &invscols, 0,
OCI_ATTR_SHOW_INVISIBLE_COLUMNS, errhp));
if ((retval = OCIDescribeAny(svchp, errhp, (dvoid *)tablename,
(ub4) strlen((char *) tablename),
OCI_OTYPE_NAME, (ub1)1,
OCI_PTYPE_TABLE, dschp)) != OCI_SUCCESS)
{
if (retval == OCI_NO_DATA)
{
printf("NO DATA: OCIDescribeAny on %s\n", tablename);
}
else
/* OCI_ERROR */
{
printf( "ERROR: OCIDescribeAny on %s\n", tablename);
checkerr(errhp, retval);
return;
}
}
else
{
ub1 colIsInv;
/* Get the parameter descriptor. */
checkerr (errhp, OCIAttrGet((dvoid *)dschp, (ub4)OCI_HTYPE_DESCRIBE,
(dvoid *)&parmp, (ub4 *)0, (ub4)OCI_ATTR_PARAM,
(OCIError *)errhp));
/* Get the attributes of the table. */
checkerr (errhp, OCIAttrGet((dvoid*) parmp, (ub4) OCI_DTYPE_PARAM,

8-35

Chapter 8

Examples Using OCIDescribeAny()

(dvoid*) &objid, (ub4 *) 0,
(ub4) OCI_ATTR_OBJID, (OCIError *)errhp));
/* Get the column list of the table. */
checkerr (errhp, OCIAttrGet((dvoid*) parmp, (ub4) OCI_DTYPE_PARAM,
(dvoid*) &collst, (ub4 *) 0,
(ub4) OCI_ATTR_LIST_COLUMNS, (OCIError *)errhp));
/* Get the number of columns. */
checkerr (errhp, OCIAttrGet((dvoid*) parmp, (ub4) OCI_DTYPE_PARAM,
(dvoid*) &numcols, (ub4 *) 0,
(ub4) OCI_ATTR_NUM_COLS, (OCIError *)errhp));
/* Now describe each column to know whether it is a invisible column or not. */
for (pos = 1; pos <= parmcnt; pos++)
{
/* Get the parameter descriptor for each column. */
checkerr (errhp, OCIParamGet((dvoid *)parmp, (ub4)OCI_DTYPE_PARAM, errhp,
(dvoid *)&parmdp, (ub4) pos));
.....
.....
checkerr (errhp, OCIAttrGet((dvoid*) parmdp, (ub4) OCI_DTYPE_PARAM,
(dvoid*) &colIsInv, (ub4 *) 0,
(ub4) OCI_ATTR_INVISIBLE_COL, (OCIError *)errhp));
.....
.....
}
}
.....
.....

8-36

9
LOB and BFILE Operations
This chapter describes LOB and BFILE operations.
This chapter contains these topics:
•

About Using OCI Functions for LOBs

•

About Creating and Modifying Persistent LOBs

•

About Associating a BFILE in a Table with an Operating System File

•

LOB Attributes of an Object

•

Array Interface for LOBs

•

About Using LOBs of Size Greater than 4 GB

•

LOB and BFILE Functions in OCI

•

Temporary LOB Support

•

Prefetching of LOB Data, Length, and Chunk Size

•

Options of SecureFiles LOBs

9.1 About Using OCI Functions for LOBs
OCI includes a set of functions for performing operations on large objects (LOBs) in a
database.
Persistent LOBs (BLOBs, CLOBs, NCLOBs) are stored in the database tablespaces in a way
that optimizes space and provides efficient access. These LOBs have the full
transactional support of the Oracle database. BFILEs are large data objects stored in
the server's operating system files outside the database tablespaces.
OCI also provides support for temporary LOBs, which can be used like local variables
for operating on LOB data.
BFILEs are read-only. Oracle Database supports only binary BFILEs.

Beginning with Oracle Database 12c Release 2 (12.2), most LOB functions support
Application Continuity.
Beginning with Oracle Database 12c Release 2 (12.2), OCI LOB APIs support
distributed operations on remote LOBs (CLOB, BLOB) except for OCI LOB APIs for
BFILES. This includes support for certain queries that select a remote LOB locator that
in previous releases returned an error. The only restriction is that all LOB APIs that
take in two locators should have both LOBs collocated at one database. The following
LOB functions throw an error when a remote locator is passed to it: OCILobAssign(),
OCILobLocatorAssign(), OCILobEnableBuffering(), OCILobDisableBuffering(),
OCILobFlushBuffer(), OCILobArrayRead(), OCILobArrayWrite(), and
OCILobLoadFromFile2().

9-1

Chapter 9

About Creating and Modifying Persistent LOBs

See Also:
•

OCI Demonstration Programs for code samples showing the use of
LOBs

•

$ORACLE_HOME/rdbms/demo/lobs/oci/ for specific LOB code samples

•

Oracle Database PL/SQL Packages and Types Reference for the
DBMS_LOB package

•

Oracle Database SecureFiles and Large Objects Developer's Guide

•

When Application Continuity in OCI Can Fail Over for a complete list.

•

Deprecated Lob Functions for information about support for Application
Continuity also includes some deprecated LOB functions for
compatibility.

9.2 About Creating and Modifying Persistent LOBs
LOB instances can be either persistent (stored in the database) or temporary (existing
only in the scope of your application).
Do not confuse the concept of a persistent LOB with a persistent object.
There are two ways of creating and modifying persistent LOBs:
•

Using the data interface
You can create a LOB by inserting character data into a CLOB column or RAW data
into a BLOB column directly. You can also modify LOBs by using a SQL UPDATE
statement, to bind character data into a CLOB column or RAW data into a BLOB
column.
Insert, update, and select of remote LOBs (over a dblink) is supported because
neither the remote server nor the local server is of a release earlier than Oracle
Database 10g Release 2. The data interface only supports data size up to 2 GB –
1, the maximum size of an sb4 data type.

•

Using the LOB locator
You create a new internal LOB by initializing a new LOB locator using
OCIDescriptorAlloc(), calling OCIAttrSet() to set it to empty (using the
OCI_ATTR_LOBEMPTY attribute), and then binding the locator to a placeholder in an
INSERT statement. Doing so inserts the empty locator into a table with a LOB
column or attribute. You can then perform a SELECT...FOR UPDATE operation on this

row to get the locator, and write to it using one of the OCI LOB functions.

Note:
To modify a LOB column or attribute (write, copy, trim, and so forth), you
must lock the row containing the LOB. One way to do this is to use a
SELECT...FOR UPDATE statement to select the locator before performing the
operation.

9-2

Chapter 9

About Associating a BFILE in a Table with an Operating System File

For any LOB write command to be successful, a transaction must be open. If you
commit a transaction before writing the data, you must lock the row again (by reissuing
the SELECT...FOR UPDATE statement, for example), because the commit closes the
transaction.

See Also:
•

•

Oracle Database SecureFiles and Large Objects Developer's Guide
chapter about data interface for persistent LOBs for more information
and examples
About Binding LOB Data for usage and examples for both INSERT and
UPDATE

•

OCIDescriptorAlloc()

•

OCIAttrSet()

9.3 About Associating a BFILE in a Table with an Operating
System File
The BFILENAME function can be used in an INSERT statement to associate an external
server-side (operating system) file with a BFILE column or attribute in a table.
Using BFILENAME in an UPDATE statement associates the BFILE column or attribute with a
different operating system file. OCILobFileSetName() can also be used to associate a
BFILE in a table with an operating system file. BFILENAME is usually used in an INSERT or
UPDATE statement without bind variables, and OCILobFileSetName() is used for bind
variables.

See Also:
•

OCILobFileSetName()

•

Oracle Database SecureFiles and Large Objects Developer's Guide for
more information about the BFILENAME function

9.4 LOB Attributes of an Object
An OCI application can use the OCIObjectNew() function to create a persistent or
transient object with a LOB attribute.
This section includes the following topics:
•

Writing to a LOB Attribute of an Object

•

Transient Objects with LOB Attributes

9-3

Chapter 9

LOB Attributes of an Object

See Also:
OCIObjectNew()

9.4.1 Writing to a LOB Attribute of an Object
It is possible to use OCI to create a new persistent object with a LOB attribute and
write to that LOB attribute.
The application would follow these steps when using a LOB locator:
1.

Call OCIObjectNew() to create a persistent object with a LOB attribute.

2.

Mark the object as "dirty" (modified).

3.

Flush the object, thereby inserting a row into the table.

4.

Repin the latest version of the object (or refresh the object), thereby retrieving the
object from the database and acquiring a valid locator for the LOB.

5.

Call OCIObjectWrite2() using the LOB locator in the object to write the data.

There is a second way of writing to a LOB attribute. When using the data interface,
you can bind or define character data for a CLOB attribute or RAW data for a BLOB
attribute.

See Also:
•
•

OCI Object-Relational Programming and the chapters that follow it for
more information about objects
About Binding LOB Data for usage and examples for both INSERT and
UPDATE statements

•

About Defining LOB Data for usage and examples of SELECT statements

•

OCIObjectNew()

•

OCILobWrite2()

9.4.2 Transient Objects with LOB Attributes
An application can call OCIObjectNew() and create a transient object with an internal
LOB (BLOB, CLOB, NCLOB) attribute.
However, you cannot perform any operations, such as read or write, on the LOB
attribute because transient objects with LOB attributes are not supported. Calling
OCIObjectNew() to create a transient internal LOB type does not fail, but the application
cannot use any LOB operations with the transient LOB.
An application can, however, create a transient object with a BFILE attribute and use
the BFILE attribute to read data from a file stored in the server's file system. The
application can also call OCIObjectNew() to create a transient BFILE.

9-4

Chapter 9

Array Interface for LOBs

See Also:
OCIObjectNew()

9.5 Array Interface for LOBs
You can use the OCI array interface with LOBs, just as with any other data type.
There are two ways of using the array interface.
•

Using the data interface
You can bind or define arrays of character data for a CLOB column or RAW data for a
BLOB column. You can use array bind and define interfaces to insert and select
multiple rows with LOBs in one round-trip to the server.

•

Using the LOB locator
When using the LOB locator you must allocate the descriptors, as shown in the
following code example.
Using the LOB Locator and Allocating the Descriptors
/* First create an array of OCILobLocator pointers: */
OCILobLocator *lobp[10];
for (i=0; i < 10; i++)
{ OCIDescriptorAlloc (...,&lobp[i],...);
/* Then bind the descriptor as follows */
OCIBindByPos(... &lobp[i], ...);

See Also:
•

About Binding LOB Data for usage and examples for both INSERT and
UPDATE statements

•

About Defining LOB Data for usage and examples of SELECT statements

9.6 About Using LOBs of Size Greater than 4 GB
Starting with Oracle Database 10g Release 1 of OCI, functions were introduced to
support LOBs of size greater than 4 GB. These new functions can also be used in new
applications for LOBs of less than 4 GB.
Oracle Database enables you to create tablespaces with block sizes different from the
database block size. The maximum size of a LOB depends on the size of the
tablespace blocks. The tablespace block size in which the LOB is stored controls the
value of CHUNK, which is a parameter of LOB storage. When you create a LOB column,
you specify a value for CHUNK, which is the number of bytes to be allocated for LOB
manipulation. The value must be a multiple of the tablespace block size, or Oracle
Database rounds up to the next multiple. (If the tablespace block size equals the

9-5

Chapter 9

About Using LOBs of Size Greater than 4 GB

database block size, then CHUNK is also a multiple of the database block size.) The
default CHUNK size is one tablespace block, and the maximum value is 32 KB.
In this guide, 4 GB is defined as 4 gigabytes – 1, or 4,294,967,295 bytes. The
maximum size of a LOB, persistent or temporary, is (4 gigabytes – 1) * (CHUNK). The
maximum LOB size can range from 8 terabytes (TB) to 128 TB.
For example, suppose that your database block size is 32 KB and you create a
tablespace with a nonstandard block size of 8 KB. Further suppose that you create a
table with a LOB column and specify a CHUNK size of 16 KB (which is a multiple of the 8
KB tablespace block size). Then the maximum size of a LOB in this column is (4
gigabytes – 1) * 16 KB.
The maximum size of a BFILE is the maximum file size allowed in the operating system,
or UB8MAXVAL, whichever is smaller.
Older LOB functions use ub4 as the data types of some parameters, and the ub4 data
type can only hold up to 4 GB. The newer functions use parameters of 8-byte length,
oraub8, which is a data type defined in oratypes.h. The data types oraub8 and orasb8
are mapped to appropriate 64-bit native data types depending on the compiler and
operating system. Macros are used to not define oraub8 and orasb8 if compiling in 32bit mode with strict ANSI option.
OCILobGetChunkSize() returns the usable chunk size in bytes for BLOBs, CLOBs, and
NCLOBs. The number of bytes stored in a chunk is actually less than the size of the
CHUNK parameter due to internal storage overhead. The function
OCILobGetStorageLimit() is provided to return the maximum size in bytes of internal

LOBs in the current installation.

Note:
Oracle Database does not support BFILEs larger than 4 gigabytes in any
programmatic environment. An additional file size limit imposed by your
operating system also applies to BFILEs.

This section includes the following topics:
•

Functions to Use for the Increased LOB Sizes

•

Compatibility and Migration

•

OCILobGetChunkSize()

•

OCILobGetStorageLimit()

9.6.1 Functions to Use for the Increased LOB Sizes
Eight functions with names that end in "2" and that use the data type oraub8 in place of
the data type ub4 were introduced in Oracle Database 10g Release 1.
Other changes were made in the read and write functions (OCILobRead2(),
OCILobWrite2(), and OCILobWriteAppend2()) to solve several problems:
Problem: Before Oracle Database 10g Release 1, the parameter amtp assumed either
byte or char length for LOBs based on the locator type and character set. It was

9-6

Chapter 9

About Using LOBs of Size Greater than 4 GB

complicated and users did not have the flexibility to use byte length or char length
according to their requirements.
Solution: Read/Write calls should take both byte_amtp and char_amtp parameters as
replacement for the amtp parameter. The char_amtp parameter is preferred for CLOB and
NCLOB, and the byte_amtp parameter is only considered as input if char_amtp is zero. On
output for CLOB and NCLOB, both byte_amtp and char_amtp parameters are filled. For BLOB
and BFILE, the char_ampt parameter is ignored for both input and output.
Problem: For OCILobRead2(), there is no flag to indicate polling mode. There is no easy
way for the users to say "I have a 100-byte buffer. Fill it as much as you can."
Previously, they had to estimate how many characters to specify for the amount. If
they guessed too much, they were forced into polling mode unintentionally. The user
code thus can get trapped in the polling mode and subsequent OCI calls are all
blocked.
Solution: This call should take piece as an input parameter and if OCI_ONE_PIECE is
passed, it should fill the buffer as much as possible and come out even if the amount
indicated by the byte_amtp parameter or char_amtp parameter is more than the buffer
length. The value of bufl is used to specify the maximum amount of bytes to read.
Problem: After calling for a LOB write in polling mode, users do not know how many
chars or bytes are actually fetched till the end of the polling.
Solution: Both the byte_amtp and char_amtp parameters must be updated after each call
in polling mode.
Problem: While reading or writing data in streaming mode with callback, users must
use the same buffer for each piece of data.
Solution: The callback function must have two new parameters to provide the buffer
and the buffer length. Callback functions can set the buffer parameter to NULL to follow
old behavior: to use the default buffer passed in the first call for all the pieces.

See Also:
•

LOB Functions

•

OCILobRead2()

•

OCILobWrite2()

•

OCILobWriteAppend2()

9.6.2 Compatibility and Migration
Existing OCI programs can be enhanced to process larger amounts of LOB data that
are greater than 4 GB.
Table 9-1 summarizes compatibility issues in this table, "old" refers to releases before
Oracle Database 10g Release 1, and NA means not applicable.

9-7

Chapter 9

About Using LOBs of Size Greater than 4 GB

Table 9-1

LOB Functions Compatibility and Migration

LOB Function

Old Client/New or Old
Server1

New Client/Old Server

New Client/New Server

OCILobArrayRead()

2NA

OK until piece size and
offset are < 4 GB.

OK

OCILobArrayWrite()

NA

OK until piece size and
offset are < 4 GB.

OK

OCILobCopy2()

NA

OK until LOB size, piece
size (amount) and offset
are < 4 GB.

OK

OCILobCopy()

OK; limit is 4 GB.

OK

OK; limit is 4 GB.

OCILobErase2()

NA

OK until piece size and
offset are < 4 GB.

OK

OCILobErase()

OK; limit is 4 GB.

OK

OK; limit is 4 GB.

OCILobGetLength2()

NA

OK

OK

OCILobGetLength()

OK; limit is 4 GB.

OK

OK; OCI_ERROR if LOB
size > 4 GB.

OCILobLoadFromFile2()

NA

OK until LOB size, piece
size (amount), and offset
are < 4 GB.

OK

OCILobLoadFromFile()

OK; limit is 4 GB.

OK

OK; limit is 4 GB.

OCILobRead2()

NA

OK until LOB size, piece
size (amount), and offset
are < 4 GB.

OK

OCILobRead()

OK; limit 4 GB.

OK

OK.

With new server:
OCI_ERROR is returned if
you try to read any amount
>= 4 GB from any offset <
4 GB. This is because
when you read any amount
>= 4 GB, that results in an
overflow of returned value
in *amtp, and so it is
flagged as an error.

OCI_ERROR is returned if
you try to read any
amount >= 4 GB from
any offset < 4 GB. This
is because when you
read any amount >= 4
GB, that results in an
overflow of returned
value in *amtp, and so it
is flagged as an error.

Note:

Note:

•

•

•

If you read up to 4 GB
– 1 from offset, that is
not flagged as an
error.
When you use
streaming mode with
polling, no error is
returned if no attempt
is made to use piece
size > 4 GB (you can
read data > 4 GB in
this case).

•

If you read up to 4
GB – 1 from offset,
that is not to be
flagged as an error.
When you use
streaming mode
with polling, no error
is returned if no
attempt is made to
use piece size > 4
GB.

OCILobTrim2()

NA

OK

OK

OCILobTrim()

OK; limit 4 GB.

OK

OK; limit 4 GB.

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Table 9-1

(Cont.) LOB Functions Compatibility and Migration

LOB Function

Old Client/New or Old
Server1

New Client/Old Server

New Client/New Server

OCILobWrite2()

NA

OK until LOB size, piece
size (amount) and offset
are < 4 GB.

OK

OCILobWrite()

OK; limit 4 GB.

OK

OK.

With new server:

OCI_ERROR is returned if
you write any amount >
=4 GB (from any offset <
4 GB) because that
results in an overflow of
returned value in *amtp.

OCI_ERROR is returned if
you write any amount >= 4
GB (from any offset < 4
GB) because that results
an in overflow of returned
value in *amtp.

Note: Updating a LOB of
10 GB from any offset
up to 4 GB –1 by up to 4
GB –1 amount of data is
not flagged as an error.

Note: Updating a LOB of
10 GB from any offset up
to 4 GB –1 by up to 4 GB –
1 amount of data is not
flagged as an error.
OCILobWriteAppend2()

NA

OK until LOB size and
piece size are <4 GB.

OK

OCILobWriteAppend()

OK; limit 4 GB.

OK

OK; limit 4 GB.

With new server:
OCI_ERROR is returned if
you append any amount
>= 4 GB of data because
that results in an overflow
of returned value in *amtp.
OCILobGetStorageLimit()
1
2

NA

OCI_ERROR is returned if
you append any amount
>= 4 GB of data
because that results in
an overflow of returned
value in *amtp.
Error

OK

The term "old" refers to releases before Oracle Database 10g Release 1.
NA means not applicable.

Use the functions that end in "2" when using the current server and current client.
Mixing deprecated functions with functions that end in "2" can result in unexpected
situations, such as data written using OCILobWrite2() being greater than 4 GB if the
application tries to read it with OCILobRead() and gets only partial data (if a callback
function is not used). In most cases, the application gets an error message when the
size crosses 4 GB and the deprecated functions are used. However, there is no issue
if you use those deprecated functions for LOBs of size smaller than 4 GB.

9.7 LOB and BFILE Functions in OCI
In all LOB operations that involve offsets into the data, the offset begins at 1. For LOB
operations, such as OCILobCopy2(), OCILobErase2(), OCILobLoadFromFile2(), and
OCILobTrim2(), the amount parameter is in characters for CLOBs and NCLOBs, regardless of
the client-side character set.
These LOB operations refer to the amount of LOB data on the server. When the clientside character set is of varying width, the following general rules apply to the amount
and offset parameters in LOB calls:

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•

amount - When the amount parameter refers to the server-side LOB, the amount is

in characters. When the amount parameter refers to the client-side buffer, the
amount is in bytes.
•

offset - Regardless of whether the client-side character set is varying-width, the
offset parameter is always in characters for CLOBs or NCLOBs and in bytes for BLOBs
or BFILEs.

Exceptions to these general rules are noted in the description of the specific LOB call.
This section includes the following topics:
•

About Improving LOB Read/Write Performance

•

LOB Buffering Functions

•

Functions for Opening and Closing LOBs

•

LOB Read and Write Callbacks

See Also:
•

LOB Functions

•

Buffer Expansion During OCI Binding

•

OCILobCopy2()

•

OCILobErase2()

•

OCILobLoadFromFile2()

•

OCILobTrim2()

9.7.1 About Improving LOB Read/Write Performance
How to improve LOB Read/Write performance.
Here are some hints to improve performance:
•

About Using Data Interface for LOBs

•

About Using OCILobGetChunkSize()

•

About Using OCILobWriteAppend2()

•

About Using OCILobArrayRead() and OCILobArrayWrite()

9.7.1.1 About Using Data Interface for LOBs
You can bind or define character data for a CLOB column or RAW data for a BLOB column.
This requires only one round-trip for inserting or selecting a LOB, as opposed to the
traditional LOB interface that requires multiple round-trips.

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See Also:
•

About Binding LOB Data for usage and examples for both INSERT and
UPDATE statements

•

About Defining LOB Data for usage and examples of SELECT statements

9.7.1.2 About Using OCILobGetChunkSize()
OCILobGetChunkSize() returns the usable chunk size in bytes for BLOBs, CLOBs, and
NCLOBs.

You can use the OCILobGetChunkSize() call to improve the performance of LOB read
and write operations for BasicFile LOBs. When a read or write is done on BasicFile
LOB data whose size is a multiple of the usable chunk size and the operation starts on
a chunk boundary, performance is improved. There is no requirement for SecureFile
LOBs to be written or read with OCILobGetChunkSize() alignment.
Calling OCILobGetChunkSize() returns the usable chunk size of the LOB, so that an
application can batch a series of write operations for the entire chunk, rather than
issuing multiple LOB write calls for the same chunk.

See Also:
•

Options of SecureFiles LOBs

•

OCILobGetChunkSize()

9.7.1.3 About Using OCILobWriteAppend2()
OCI provides a shortcut for more efficient writing of data to the end of a LOB.
The OCILobWriteAppend2() call appends data to the end of a LOB without first requiring
a call to OCILobGetLength2() to determine the starting point for an OCILobWrite2()
operation. OCILobWriteAppend2() does both steps.

See Also:
•

OCILobWriteAppend2()

•

OCILobGetLength2()

•

OCILobWrite2()

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9.7.1.4 About Using OCILobArrayRead() and OCILobArrayWrite()
You can improve performance by using by using OCILobArrayRead() to read LOB data
for multiple LOB locators and OCILobArrayWrite() to write LOB data for multiple LOB
locators.
These functions, which were introduced in Oracle Database 10g Release 2, reduce
the number of round-trips for these operations.

See Also:
•

Oracle Database SecureFiles and Large Objects Developer's Guide
sections "LOB Array Read" and "LOB Array Write" for more information
and code examples that show how to use these functions with callback
functions and in piecewise mode

•

OCILobArrayRead()

•

OCILobArrayWrite()

9.7.2 LOB Buffering Functions
These LOB functions are deprecated. Use the LOB prefetch feature in place of these
LOB buffering functions.
OCI provides several calls for controlling LOB buffering for small reads and writes of
internal LOB values:
•

OCILobEnableBuffering()

•

OCILobDisableBuffering()

•

OCILobFlushBuffer()

These functions enable applications that are using internal LOBs (BLOB, CLOB, NCLOB) to
buffer small reads and writes in client-side buffers. This reduces the number of
network round-trips and LOB versions, thereby improving LOB performance
significantly.

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See Also:
•

Oracle Database SecureFiles and Large Objects Developer's Guide for
more information on LOB buffering, see the chapter about using LOB
APIs.

•

LOB Function Round-Trips for a list of the server round-trips required for
each function

•

Prefetching of LOB Data, Length, and Chunk Size

•

OCILobEnableBuffering()

•

OCILobDisableBuffering()

•

OCILobFlushBuffer()

9.7.3 Functions for Opening and Closing LOBs
OCI provides functions to explicitly open a LOB, OCILobOpen(), to close a LOB,
OCILobClose(), and to test whether a LOB is open, OCILobIsOpen().
These functions mark the beginning and end of a series of LOB operations so that
specific processing, such as updating indexes, can be performed when a LOB is
closed.
For internal LOBs, the concept of openness is associated with a LOB and not its
locator. The locator does not store any information about the state of the LOB. It is
possible for more than one locator to point to the same open LOB. However, for
BFILEs, being open is associated with a specific locator. Hence, more than one open
call can be performed on the same BFILE by using different locators.
If an application does not wrap LOB operations within a set of OCILobOpen() and
OCILobClose() calls, then each modification to the LOB implicitly opens and closes the
LOB, thereby firing any triggers associated with changes to the LOB.
If LOB operations are not wrapped within open and close calls, any extensible indexes
on the LOB are updated as LOB modifications are made, and thus are always valid
and may be used at any time. If the LOB is modified within a set of OCILobOpen() and
OCILobClose() calls, triggers are not fired for individual LOB modifications. Triggers are
only fired after the OCILobClose() call, so indexes are not updated until after the close
call and thus are not valid within the open and close calls. OCILobIsOpen() can be used
with internal LOBs and BFILEs.
An error is returned when you commit the transaction before closing all opened LOBs
that were opened by the transaction. When the error is returned, the LOB is no longer
marked as open, but the transaction is successfully committed. Hence, all the changes
made to the LOB and non-LOB data in the transaction are committed, but the domain
and functional indexing are not updated. If this happens, rebuild your functional and
domain indexes on the LOB column.
A LOB opened when there is no transaction must be closed before the end of the
session. If there are LOBs open at the end of session, the LOB is no longer marked as
open and the domain and functional indexing is not updated. If this happens, rebuild
your functional and domain indexes on the LOB column.

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This section includes the following topic: Restrictions on Opening and Closing LOBs.

See Also:
•

OCILobOpen()

•

OCILobClose()

•

OCILobIsOpen()

9.7.3.1 Restrictions on Opening and Closing LOBs
What are the restrictions on opening and closing LOBs.
The LOB opening and closing mechanism has the following restrictions:
•

An application must close all previously opened LOBs before committing a
transaction. Failing to do so results in an error. If a transaction is rolled back, all
open LOBs are discarded along with the changes made. Because the LOBs are
not closed, so the associated triggers are not fired.

•

Although there is no limit to the number of open internal LOBs, there is a limit on
the number of open files as determined by the SESSION_MAX_OPEN_FILES parameter.
Assigning an already opened locator to another locator does not count as opening
a new LOB.

•

It is an error to open or close the same internal LOB twice within the same
transaction, either with different locators or the same locator.

•

It is an error to close a LOB that has not been opened.

Note:
The definition of a transaction within which an open LOB value must be
closed is one of the following:
–

Between SET TRANSACTION and COMMIT

–

Between DATA MODIFYING DML or SELECT ... FOR UPDATE and COMMIT.

–

Within an autonomous transaction block

See Also:
•

SESSION_MAX_OPEN_FILES parameter in Oracle Database Reference

•

OCI Demonstration Programs for examples of the use of the
OCILobOpen() and OCILobClose() calls in the online demonstration
programs

•

Table C-2

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9.7.4 LOB Read and Write Callbacks
OCI supports read and write callback functions.
The following sections describe the use of callbacks in more detail:
•

Callback Interface for Streaming

•

Reading LOBs by Using Callbacks

•

Writing LOBs by Using Callbacks

9.7.4.1 Callback Interface for Streaming
User-defined read and write callback functions for inserting or retrieving data provide
an alternative to the polling methods for streaming LOBs.
These functions are implemented by you and registered with OCI through the
OCILobRead2(), OCILobWriteAppend2(), and OCILobWrite2() calls. These callback

functions are called by OCI whenever they are required.

See Also:
•

OCILobRead2()

•

OCILobWriteAppend2()

•

OCILobWrite2()

9.7.4.2 Reading LOBs by Using Callbacks
The user-defined read callback function is registered through the OCILobRead2()
function.
The callback function should have the following prototype:
CallbackFunctionName ( void *ctxp, CONST void *bufp, oraub8 len, ub1 piece,
void **changed_bufpp, oraub8 *changed_lenp);

The first parameter, ctxp, is the context of the callback that is passed to OCI in the
OCILobRead2() function call. When the callback function is called, the information
provided by you in ctxp is passed back to you (OCI does not use this information on
the way IN). The bufp parameter in OCILobRead2()) is the pointer to the storage where
the LOB data is returned and bufl is the length of this buffer. It tells you how much
data has been read into the buffer provided.
If the buffer length provided in the original OCILobRead2() call is insufficient to store all
the data returned by the server, then the user-defined callback is called. In this case,
the piece parameter indicates whether the information returned in the buffer is the first,
next, or last piece.
The parameters changed_bufpp and changed_lenp can be used inside the callback
function to change the buffer dynamically. The changed_bufpp parameter should point to
the address of the changed buffer and the changed_lenp parameter should point to the
length of the changed buffer. The changed_bufpp and changed_lenp parameters need not

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be used inside the callback function if the application does not change the buffer
dynamically.
Example 9-1 shows a code fragment that implements read callback functions using
OCILobRead2(). Assume that lobl is a valid locator that has been previously selected,
svchp is a valid service handle, and errhp is a valid error handle. In the example, the
user-defined function cbk_read_lob() is repeatedly called until all the LOB data has

been read.
Example 9-1
...
oraub8
oraub8
oraub8
oraub8
ub1

Implementing Read Callback Functions Using OCILobRead2()

offset = 1;
loblen = 0;
byte_amt = 0;
char_amt = 0
bufp[MAXBUFLEN];

sword retval;
byte_amtp = 4294967297;

/* 4 gigabytes plus 1 */

if (retval = OCILobRead2(svchp, errhp, lobl, &byte_amt, &char_amt, offset,
(void *) bufp, (oraub8) MAXBUFLEN, (void *) 0, OCI_FIRST_PIECE,
cbk_read_lob, (ub2) 0, (ub1) SQLCS_IMPLICIT))
{
(void) printf("ERROR: OCILobRead2() LOB.\n");
report_error();
}
...
sb4 cbk_read_lob(ctxp, bufxp, len, piece, changed_bufpp, changed_lenp)
void
*ctxp;
CONST void *bufxp;
oraub8
len;
ub1
piece;
void
**changed_bufpp;
oraub8
*changed_lenp;
{
static ub4 piece_count = 0;
piece_count++;
switch (piece)
{
case OCI_LAST_PIECE:
/*--- buffer processing code goes here ---*/
(void) printf("callback read the %d th piece\n\n", piece_count);
piece_count = 0;
break;
case OCI_FIRST_PIECE: /*--- buffer processing code goes here ---*/
(void) printf("callback read the %d th piece\n", piece_count);
/* --Optional code to set changed_bufpp and changed_lenp if the
buffer must be changed dynamically --*/
break;
case OCI_NEXT_PIECE: /*--- buffer processing code goes here ---*/
(void) printf("callback read the %d th piece\n", piece_count);
/* --Optional code to set changed_bufpp and changed_lenp if the
buffer must be changed dynamically --*/
break;
default:
(void) printf("callback read error: unknown piece = %d.\n", piece);
return OCI_ERROR;
}

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return OCI_CONTINUE;
}

See Also:
OCILobRead2()

9.7.4.3 Writing LOBs by Using Callbacks
Similar to read callbacks, the user-defined write callback function is registered through
the OCILobWrite2() function.
The callback function should have the following prototype:
CallbackFunctionName ( void *ctxp, void *bufp, oraub8 *lenp, ub1 *piecep,
void **changed_bufpp, oraub8 *changed_lenp);

The first parameter, ctxp, is the context of the callback that is passed to OCI in the
OCILobWrite2() function call. The information provided by you in ctxp is passed back to
you when the callback function is called by OCI (OCI does not use this information on
the way IN). The bufp parameter is the pointer to a storage area; you provide this
pointer in the call to OCILobWrite2().
After inserting the data provided in the call to OCILobWrite2() any data remaining is
inserted by the user-defined callback. In the callback, provide the data to insert in the
storage indicated by bufp and also specify the length in lenp. You also indicate
whether it is the next (OCI_NEXT_PIECE) or the last (OCI_LAST_PIECE) piece using the
piecep parameter. You must ensure that the storage pointer that is provided by the
application does not write more than the allocated size of the storage.
The parameters changed_bufpp and changed_lenp can be used inside the callback
function to change the buffer dynamically. The changed_bufpp parameter should point to
the address of the changed buffer and the changed_lenp parameter should point to the
length of the changed buffer. The changed_bufpp and changed_lenp parameters need not
be used inside the callback function if the application does not change the buffer
dynamically.
Example 9-2 shows a code fragment that implements write callback functions using
OCILobWrite2(). Assume that lobl is a valid locator that has been locked for updating,
svchp is a valid service handle, and errhp is a valid error handle. The user-defined
function cbk_write_lob() is repeatedly called until the piecep parameter indicates that

the application is providing the last piece.
Example 9-2

Implementing Write Callback Functions Using OCILobWrite2()

...
ub1
oraub8
oraub8
oraub8
oraub8

bufp[MAXBUFLEN];
byte_amt = MAXBUFLEN * 20;
char_amt = 0;
offset = 1;
nbytes = MAXBUFLEN;

/*-- code to fill bufp with data goes here. nbytes should reflect the size and
should be less than or equal to MAXBUFLEN --*/
if (retval = OCILobWrite2(svchp, errhp, lobl, &byte_amt, &char_amt, offset,

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(void*)bufp, (ub4)nbytes, OCI_FIRST_PIECE, (void *)0, cbk_write_lob,
(ub2) 0, (ub1) SQLCS_IMPLICIT))
{
(void) printf("ERROR: OCILobWrite2().\n");
report_error();
return;
}
...
sb4 cbk_write_lob(ctxp, bufxp, lenp, piecep, changed_bufpp, changed_lenp)
void
*ctxp;
void
*bufxp;
oraub8 *lenp;
ub1
*piecep;
void **changed_bufpp;
oraub8 *changed_lenp;
{
/*-- code to fill bufxp with data goes here. *lenp should reflect the
size and should be less than or equal to MAXBUFLEN -- */
/* --Optional code to set changed_bufpp and changed_lenp if the
buffer must be changed dynamically --*/
if (this is the last data buffer)
*piecep = OCI_LAST_PIECE;
else
*piecep = OCI_NEXT_PIECE;
return OCI_CONTINUE;
}

See Also:
OCILobWrite2()

9.8 Temporary LOB Support
OCI provides functions for creating and freeing temporary LOBs,
OCILobCreateTemporary() and OCILobFreeTemporary(), and a function for determining
whether a LOB is temporary, OCILobIsTemporary().
Temporary LOBs are not permanently stored in the database, but act like local
variables for operating on LOB data. OCI functions that operate on standard
(persistent) LOBs can also be used on temporary LOBs.
As with persistent LOBs, all functions operate on the locator for the temporary LOB,
and the actual LOB data is accessed through the locator.
Temporary LOB locators can be used as arguments to the following types of SQL
statements:
•

UPDATE - The temporary LOB locator can be used as a value in a WHERE clause

when testing for nullity or as a parameter to a function. The locator can also be
used in a SET clause.
•

DELETE - The temporary LOB locator can be used in a WHERE clause when testing for

nullity or as a parameter to a function.
•

SELECT - The temporary LOB locator can be used in a WHERE clause when testing for

nullity or as a parameter to a function. The temporary LOB can also be used as a

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return variable in a SELECT...INTO statement when selecting the return value of a
function.

Note:
If you select a permanent locator into a temporary locator, the temporary
locator is overwritten with the permanent locator. In this case, the temporary
LOB is not implicitly freed. You must explicitly free the temporary LOB before
the SELECT...INTO operation. If the temporary LOB is not freed explicitly, it is
not freed until the end of its specified duration. Unless you have another
temporary locator pointing to the same LOB, you no longer have a locator
pointing to the temporary LOB, because the original locator was overwritten
by the SELECT...INTO operation.

This section includes the following topics:
•

Creating and Freeing Temporary LOBs

•

Temporary LOB Durations

•

About Freeing Temporary LOBs

•

Take Care When Assigning Pointers

•

Temporary LOB Example

See Also:
•

OCILobCreateTemporary()

•

OCILobFreeTemporary()

•

OCILobIsTemporary()

9.8.1 Creating and Freeing Temporary LOBs
You create a temporary LOB with the OCILobCreateTemporary() function.
The parameters passed to this function include a value for the duration of the LOB.
The default duration is for the length of the current session. All temporary LOBs are
deleted at the end of the duration. Users can reclaim temporary LOB space by
explicitly freeing the temporary LOB with the OCILobFreeTemporary() function. A
temporary LOB is empty when it is created.
When creating a temporary LOB, you can also specify whether the temporary LOB is
read into the server's buffer cache.
To make a temporary LOB permanent, use OCILobCopy2() to copy the data from the
temporary LOB into a permanent one. You can also use the temporary LOB in the
VALUES clause of an INSERT statement, as the source of the assignment in an UPDATE
statement, or assign it to a persistent LOB attribute and then flush the object.
Temporary LOBs can be modified using the same functions that are used for standard
LOBs.

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Note:
The most efficient way to insert an empty LOB is to bind a temporary LOB
with no value assigned to it. This uses less resources than the following
method.
INSERT INTO tab1 VALUES(EMPTY_CLOB())

See Also:
•

OCILobCreateTemporary()

•

OCILobFreeTemporary()

•

OCILobCopy2()

9.8.2 Temporary LOB Durations
OCI supports several predefined durations for temporary LOBs, and a set of functions
that the application can use to define application-specific durations.
The predefined durations and their associated attributes are:
•

Call, OCI_DURATION_CALL, only on the server side

•

Session, OCI_DURATION_SESSION

The session duration expires when the containing session or connection ends. The
call duration expires at the end of the current OCI call.
When you run in object mode, you can also define application-specific durations. An
application-specific duration, also referred to as a user duration, is defined by
specifying the start of a duration using OCIDurationBegin() and the end of the duration
using OCIDurationEnd().

Note:
User-defined durations are only available if an application has been
initialized in object mode.

Each application-specific duration has a duration identifier that is returned by
OCIDurationBegin() and is guaranteed to be unique until OCIDurationEnd() is called. An

application-specific duration can be as long as a session duration.
At the end of a duration, all temporary LOBs associated with that duration are freed.
The descriptor associated with the temporary LOB must be freed explicitly with the
OCIDescriptorFree() call.

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User-defined durations can be nested; one duration can be defined as a child duration
of another user duration. It is possible for a parent duration to have child durations that
have their own child durations.

Note:
When a duration is started with OCIDurationBegin(), one of the parameters is
the identifier of a parent duration. When a parent duration is ended, all child
durations are also ended.

See Also:
•

OCIDurationBegin()

•

OCIDurationEnd()

•

OCIDescriptorFree()

9.8.3 About Freeing Temporary LOBs
Any time that your OCI program obtains a LOB locator from SQL or PL/SQL, use the
OCILobIsTemporary() function to check that the locator is temporary.

If it is, then free the locator when your application is finished with it by using the
OCILobFreeTemporary() call. The locator can be from a define during a select or an out
bind. A temporary LOB duration is always upgraded to a session duration when it is
shipped to the client side. The application must do the following before the locator is
overwritten by the locator of the next row:
OCILobIsTemporary(env, err, locator, is_temporary);
if(is_temporary)
OCILobFreeTemporary(svc, err, locator);

See Also:
•

OCILobIsTemporary()

•

OCILobFreeTemporary()

9.8.4 Take Care When Assigning Pointers
Special care must be taken when assigning OCILobLocator pointers.
Pointer assignments create a shallow copy of the LOB. After the pointer assignment,
source and target LOBs point to the same copy of data. This behavior is different from
using LOB APIs, such as OCILobAssign() or OCILobLocatorAssign(), to perform
assignments. When the APIs are used, the locators logically point to independent
copies of data after assignment.

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For temporary LOBs, before pointer assignments, you must ensure that any temporary
LOB in the target LOB locator is freed by OCILobFreeTemporary(). When
OCILobLocatorAssign() is used, the original temporary LOB in the target LOB locator
variable, if any, is freed before the assignment happens.
Before an out-bind variable is reused in executing a SQL statement, you must free any
temporary LOB in the existing out-bind LOB locator buffer by using the
OCILobFreeTemporary() call.

See Also:
•

Oracle Database SecureFiles and Large Objects Developer's Guide for
information in the section about temporary LOB performance guidelines

•

Oracle Database SecureFiles and Large Objects Developer's Guide for a
discussion of optimal performance of temporary LOBs

•

OCILobAssign()

•

OCILobLocatorAssign()

•

OCILobFreeTemporary()

•

OCILobLocatorAssign()

9.8.5 Temporary LOB Example
Shows how temporary LOBs can be used.
Example 9-3 shows how temporary LOBs can be used.
Example 9-3
#include
#include
#include
#include

Using Temporary LOBs






/* Function Prototype */
static void checkerr (/*_ OCIError *errhp, sword status _*/);
sb4 select_and_createtemp (OCILobLocator *lob_loc,
OCIError
*errhp,
OCISvcCtx
*svchp,
OCIStmt
*stmthp,
OCIEnv
*envhp);
/* This function reads in a single video frame from the print_media table.
Then it creates a temporary LOB. The temporary LOB that is created is read
through the CACHE, and is automatically cleaned up at the end of the user's
session, if it is not explicitly freed sooner. This function returns OCI_SUCCESS
if it completes successfully or OCI_ERROR if it fails. */
sb4 select_and_createtemp (OCILobLocator
OCIError
OCISvcCtx
OCIStmt
OCIEnv
{
OCIDefine
*defnp1;

*lob_loc,
*errhp,
*svchp,
*stmthp,
*envhp)

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OCIBind
*bndhp;
text
*sqlstmt;
int rowind =1;
ub4 loblen = 0;
OCILobLocator *tblob;
printf ("in select_and_createtemp \n");
if(OCIDescriptorAlloc((void*)envhp, (void **)&tblob,
(ub4)OCI_DTYPE_LOB, (size_t)0, (void**)0))
{
printf("failed in OCIDescriptor Alloc in select_and_createtemp \n");
return OCI_ERROR;
}
/* arbitrarily select where Clip_ID =1 */
sqlstmt=(text *)"SELECT Frame FROM print_media WHERE product_ID = 1 FOR UPDATE";
if (OCIStmtPrepare2(svchp, stmthp, errhp, sqlstmt, (ub4) strlen((char *)sqlstmt),
NULL, 0, (ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT))
{
(void) printf("FAILED: OCIStmtPrepare() sqlstmt\n");
return OCI_ERROR;
}
/* Define for BLOB */
if (OCIDefineByPos(stmthp, &defnp1, errhp, (ub4)1, (void *) &lob_loc, (sb4)0,
(ub2) SQLT_BLOB, (void *)0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT))
{
(void) printf("FAILED: Select locator: OCIDefineByPos()\n");
return OCI_ERROR;
}
/* Execute the select and fetch one row */
if (OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4) 0,
(CONST OCISnapshot*) 0, (OCISnapshot*) 0, (ub4) OCI_DEFAULT))
{
(void) printf("FAILED: OCIStmtExecute() sqlstmt\n");
return OCI_ERROR;
}
if(OCILobCreateTemporary(svchp, errhp, tblob, (ub2)0, SQLCS_IMPLICIT,
OCI_TEMP_BLOB, OCI_ATTR_NOCACHE, OCI_DURATION_SESSION))
{
(void) printf("FAILED: CreateTemporary() \n");
return OCI_ERROR;
}
if (OCILobGetLength(svchp, errhp, lob_loc, &loblen) != OCI_SUCCESS)
{
printf("OCILobGetLength FAILED\n");
return OCI_ERROR;
}
if (OCILobCopy(svchp, errhp, tblob,lob_loc,(ub4)loblen, (ub4) 1, (ub4) 1))
{
printf( "OCILobCopy FAILED \n");
}
if(OCILobFreeTemporary(svchp,errhp,tblob))
{
printf ("FAILED: OCILobFreeTemporary call \n");
return OCI_ERROR;
}
return OCI_SUCCESS;
}
int main(char *argv, int argc)
{
/* OCI Handles */
OCIEnv
*envhp;
OCIServer
*srvhp;

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Chapter 9

Temporary LOB Support

OCISvcCtx
*svchp;
OCIError
*errhp;
OCISession
*authp;
OCIStmt
*stmthp;
OCILobLocator *clob, *blob;
OCILobLocator *lob_loc;
int type =1;
/* Initialize and Log on */
OCIEnvCreate(&envhp, OCI_DEFAULT, (void *)0, 0, 0, 0,
(size_t)0, (void *)0);
(void) OCIHandleAlloc( (void *) envhp, (void **) &errhp, OCI_HTYPE_ERROR,
(size_t) 0, (void **) 0);
/* server contexts */
(void) OCIHandleAlloc( (void *) envhp, (void **) &srvhp, OCI_HTYPE_SERVER,
(size_t) 0, (void **) 0);
/* service context */
(void) OCIHandleAlloc( (void *) envhp, (void **) &svchp, OCI_HTYPE_SVCCTX,
(size_t) 0, (void **) 0);
/* attach to Oracle Database */
(void) OCIServerAttach( srvhp, errhp, (text *)"", strlen(""), 0);
/* set attribute server context in the service context */
(void) OCIAttrSet ((void *) svchp, OCI_HTYPE_SVCCTX,
(void *)srvhp, (ub4) 0,
OCI_ATTR_SERVER, (OCIError *) errhp);
(void) OCIHandleAlloc((void *) envhp,
(void **)&authp, (ub4) OCI_HTYPE_SESSION,
(size_t) 0, (void **) 0);
(void) OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_SESSION,
(void *) "scott", (ub4)5,
(ub4) OCI_ATTR_USERNAME, errhp);
(void) OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_SESSION,
(void *) "password", (ub4) 5,
(ub4) OCI_ATTR_PASSWORD, errhp);
/* Begin a User Session */
checkerr(errhp, OCISessionBegin ( svchp, errhp, authp, OCI_CRED_RDBMS,
(ub4) OCI_DEFAULT));
(void) OCIAttrSet((void *) svchp, (ub4) OCI_HTYPE_SVCCTX,
(void *) authp, (ub4) 0,
(ub4) OCI_ATTR_SESSION, errhp);
/* ------- Done logging in ----------------------------------*/
/* allocate a statement handle */
checkerr(errhp, OCIHandleAlloc( (void *) envhp, (void **) &stmthp,
OCI_HTYPE_STMT, (size_t) 0, (void **) 0));
checkerr(errhp, OCIDescriptorAlloc((void *)envhp, (void **)&lob_loc,
(ub4) OCI_DTYPE_LOB, (size_t) 0, (void **) 0));
/* Subroutine calls begin here */
printf("calling select_and_createtemp\n");
select_and_createtemp (lob_loc, errhp, svchp,stmthp,envhp);
return 0;
}
void checkerr(errhp, status)
OCIError *errhp;
sword status;
{
text errbuf[512];
sb4 errcode = 0;
switch (status)
{
case OCI_SUCCESS:
break;
case OCI_SUCCESS_WITH_INFO:

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Prefetching of LOB Data, Length, and Chunk Size

(void) printf("Error - OCI_SUCCESS_WITH_INFO\n");
break;
case OCI_NEED_DATA:
(void) printf("Error - OCI_NEED_DATA\n");
break;
case OCI_NO_DATA:
(void) printf("Error - OCI_NODATA\n");
break;
case OCI_ERROR:
(void) OCIErrorGet((void *)errhp, (ub4) 1, (text *) NULL, &errcode,
errbuf, (ub4) sizeof(errbuf), OCI_HTYPE_ERROR);
(void) printf("Error - %.*s\n", 512, errbuf);
break;
case OCI_INVALID_HANDLE:
(void) printf("Error - OCI_INVALID_HANDLE\n");
break;
case OCI_STILL_EXECUTING:
(void) printf("Error - OCI_STILL_EXECUTE\n");
break;
case OCI_CONTINUE:
(void) printf("Error - OCI_CONTINUE\n");
break;
default:
break;
}
}

9.9 Prefetching of LOB Data, Length, and Chunk Size
To improve OCI access of smaller LOBs, LOB data can be prefetched and cached
while also fetching the locator.
This applies to internal LOBs, temporary LOBs, and BFILEs. Take the following steps to
prepare your application:
1.

Set the OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE attribute for the session handle. The
value of this attribute indicates the default prefetch data size for a LOB locator.
This attribute value enables prefetching for all the LOB locators fetched in the
session. The default value for this attribute is zero (no prefetch of LOB data). This
option relieves the application developer from setting the prefetch LOB size for
each define handle. You can either set this attribute or set (in Step 3)
OCI_ATTR_LOBPREFETCH_SIZE.

2.

Perform the prepare and define steps for the statement to be executed.

3.

You can override the default prefetch size, if required, for the LOB locators to be
fetched, by setting OCI_ATTR_LOBPREFETCH_SIZE attribute for the define handle. This
optional attribute provides control of the prefetch size for the locators fetched from
a particular column.

4.

Set the OCI_ATTR_LOBPREFETCH_LENGTH attribute to the prefetch LOB length and
chunk size. This is mandatory to be set to TRUE for the attribute
(OCI_ATTR_LOBPREFETCH_SIZE) described in item 1 to work.

5.

Execute the statement.

6.

Call OCILobRead2() or OCILobArrayRead() with individual LOB locators; OCI
takes the data from the prefetch buffer, does the necessary character conversion,
and copies the data into the LOB read buffer (no change in LOB semantic). If the

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Prefetching of LOB Data, Length, and Chunk Size

data requested is bigger than the prefetch buffer, then it will require additional
round-trips.
7.

Call OCILobGetLength2() and OCILobGetChunkSize() to obtain the length and
chunk size without making round-trips to the server.

Example 9-4

Prefetching of LOB Data, Length, and Chunk Size

...
ub4 default_lobprefetch_size = 2000;
/* Set default size to 2K */
...
/* set LOB prefetch attribute to session */
OCIAttrSet (sesshp, (ub4) OCI_HTYPE_SESSION,
(void *)&default_lobprefetch_size,
/* attribute value */
0,
/* attribute size; not required to specify; */
(ub4) OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE,
errhp);
...
/* select statement */
char *stmt = "SELECT lob1 FROM lob_table";
...
/* declare and allocate LOB locator */
OCILobLocator * lob_locator;
lob_locator = OCIDescriptorAlloc(..., OCI_DTYPE_LOB, ...);
OCIDefineByPos(..., 1, (void *) &lob_locator, ..., SQLT_CLOB, ...);
...
/* Override the default prefetch size to 4KB */
ub4 prefetch_size = 4000;
OCIAttrSet (defhp, OCI_HTYPE_DEFINE,
(void *) &prefetch_size
/* attr value */,
0
/* restricting prefetch size to be ub4 max val */,
OCI_ATTR_LOBPREFETCH_SIZE
/* attr type */,
errhp);
...
/* Set prefetch length attribute */
boolean prefetch_length = TRUE;
OCIAttrSet( defhp, OCI_HTYPE_DEFINE,
(dvoid *) &prefetch_length /* attr value */,
0,
OCI_ATTR_LOBPREFETCH_LENGTH /* attr type */,
errhp );
...
/* execute the statement. 4KB of data for the LOB is read and
* cached in descriptor cache buffer.
*/
OCIStmtExecute (svchp, stmthp, errhp,
1,
/* iters */
0,
/* row offset */
NULL,
/* snapshot IN */
NULL,
/* snapshot out */
OCI_DEFAULT);
/* mode */
...
oraub8 char_amtp = 4000;
oraub8 lob_len;
ub4 chunk_size;
/* LOB chunk size, length, and data are read from cache. No round-trip. */
OCILobGetChunkSize (svchp, errhp, lob_locator, &chunk_size);
OCILobGetLength2(svchp, errhp, lob_locator, &lob_len );

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Prefetching of LOB Data, Length, and Chunk Size

OCILobRead2(svchp, errhp, lob_locator, NULL, &char_amtp, ...);
...

Note that the prefetch size is in number of bytes for BLOBs and BFILEs and in number of
characters for CLOBs.
Example 9-4 shows a code fragment illustrating these steps.
Prefetch cache allocation: The prefetch cache buffer for a descriptor is allocated
while fetching a LOB locator. The allocated buffer size is determined by the
OCI_ATTR_LOBPREFETCH_SIZE attribute for the define handle; the default value of this
attribute is indicated by the OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE attribute value of the
session handle. If the cache buffer is already allocated, then it is resized if required.
For the following two LOB APIs, if the source locator has cached data, then the
destination locator cache is allocated or resized and cached data is copied from
source to destination.
•

OCILobAssign()

•

OCILobLocatorAssign()

Once allocated, the cache buffer memory for a descriptor is released when the
descriptor itself is freed.
Prefetch cache invalidation: The cache for a descriptor gets invalidated when LOB
data is updated using the locator. Meaning the cache is no longer used for reading
data and the next OCILobRead2() call on the locator makes a round-trip.
The following LOB APIs invalidate the prefetch cache for the descriptor used:
•

OCILobErase() (deprecated)

•

OCILobErase2()

•

OCILobTrim() (deprecated)

•

OCILobTrim2()

•

OCILobWrite() (deprecated)

•

OCILobWrite2()

•

OCILobWriteAppend() (deprecated)

•

OCILobWriteAppend2()

•

OCILobArrayWrite()

The following LOB APIs invalidate the cache for the destination LOB locator:
•

OCILobAppend()

•

OCILobCopy() (deprecated)

•

OCILobCopy2()

•

OCILobLoadFromFile() (deprecated)

•

OCILobLoadFromFile2()

Performance Tuning: The prefetch buffer size must be decided upon based on
average LOB size and client-side memory. If a large amount of data is prefetched, you
must ensure the memory availability. Performance gain may not be significant for

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Chapter 9

Options of SecureFiles LOBs

prefetching large LOBs, because the cost of fetching data is much higher compared to
the cost of a round-trip to the server.
You must have a fair idea of the LOB data size to be able to make best use of this
LOB prefetch feature. Because the parameters are part of application design, the
application must be rebuilt if any parameter value must be modified.
Upgrading: LOB prefetching cannot be used against a pre-11.1 release server or in a
pre-11.1 client against an 11.1 or later server. When you use a pre-11.1 server with an
11.1 or later client, OCIAttrSet() returns an error or an error-with-information saying
that "server does not support this functionality."

See Also:
•

OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE

•

OCI_ATTR_LOBPREFETCH_LENGTH

•

OCI_ATTR_LOBPREFETCH_SIZE

9.10 Options of SecureFiles LOBs
For SecureFiles (LOBs with the STORE AS SECUREFILE option, which were introduced in
Oracle Database 11g Release 1) you can specify the SQL parameter DEDUPLICATE in
CREATE TABLE and ALTER TABLE statements.
This parameter value enables you to specify that LOB data that is identical in two or
more rows in a LOB column shares the same data blocks, thus saving disk space.
KEEP_DUPLICATES turns off this capability. The following options are also used with
SECUREFILE:
The parameter COMPRESS turns on LOB compression. NOCOMPRESS turns LOB
compression off.
The parameter ENCRYPT turns on LOB encryption and optionally selects an encryption
algorithm. NOENCRYPT turns off LOB encryption. Each LOB column can have its own
encryption specification, independent of the encryption of other LOB or non-LOB
columns. Valid algorithms are 3DES168, AES128, AES192, and AES256.
The LOBs paradigm used before release 11.1 is the default. This default LOBs
paradigm is also now explicitly set by the option STORE AS BASICFILE.
The following OCI functions are used with the SECUREFILE features:
•

OCILobGetOptions()

•

OCILobSetOptions()

•

OCILobGetContentType()

•

OCILobSetContentType()

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Chapter 9

Options of SecureFiles LOBs

See Also:
•

Oracle Database SecureFiles and Large Objects Developer's Guide for
complete details of relevant SQL functions and cross-references to
PL/SQL packages and information about migrating to SecureFiles

•

OCILobGetOptions()

•

OCILobSetOptions()

•

OCILobGetContentType()

•

OCILobSetContentType()

9-29

10
Managing Scalable Platforms
This chapter describes how OCI manages transaction operations.
This chapter contains these topics:
•

OCI Support for Transactions

•

Levels of Transactional Complexity

•

Password and Session Management

•

Middle-Tier Applications in OCI

•

Externally Initialized Context in OCI

•

Client Application Context

•

Using Edition-Based Redefinition

•

OCI Security Enhancements

•

Overview of OCI Multithreaded Development

•

OCIThread Package

10.1 OCI Support for Transactions
OCI has a set of API calls to support operations on both local and global transactions.
These calls include object support, so that if an OCI application is running in object
mode, the commit and rollback calls synchronize the object cache with the state of the
transaction.
The functions listed later perform transaction operations. Each call takes a service
context handle that must be initialized with the proper server context and user session
handle. The transaction handle is the third element of the service context; it stores
specific information related to a transaction. When a SQL statement is prepared, it is
associated with a particular service context. When the statement is executed, its
effects (query, fetch, insert) become part of the transaction that is currently associated
with the service context.
•

OCITransStart() marks the start of a transaction.

•

OCITransDetach() detaches a transaction.

•

OCITransCommit() commits a transaction.

•

OCITransRollback() rolls back a transaction.

•

OCITransPrepare() prepares a transaction to be committed in a distributed

processing environment.
•

OCITransMultiPrepare() prepares a transaction with multiple branches in a single

call.
•

OCITransForget() causes the server to forget a heuristically completed global

transaction.

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Chapter 10

Levels of Transactional Complexity

Depending on the level of transactional complexity in your application, you may need
all or only a few of these calls. The following section discusses this in more detail.

See Also:
•

Transaction Functions

•

OCITransStart()

•

OCITransDetach()

•

OCITransCommit()

•

OCITransRollback()

•

OCITransPrepare()

•

OCITransMultiPrepare()

•

OCITransForget()

10.2 Levels of Transactional Complexity
OCI supports several levels of transaction complexity.
These levels of transaction complexity include:
•

Simple Local Transactions

•

Serializable or Read-Only Local Transactions

•

Global Transactions

This section includes the following additional topics:
•

Transaction Examples

•

Initialization Parameters

10.2.1 Simple Local Transactions
Many applications work with only simple local transactions.
In these applications, an implicit transaction is created when the application makes
database changes. The only transaction-specific calls needed by such applications
are:
•

OCITransCommit() to commit the transaction

•

OCITransRollback() to roll back the transaction

As soon as one transaction has been committed or rolled back, the next modification
to the database creates a new implicit transaction for the application.
Only one implicit transaction can be active at any time on a service context. Attributes
of the implicit transaction are opaque to the user.
If an application creates multiple sessions, each one can have an implicit transaction
associated with it.

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Chapter 10

Levels of Transactional Complexity

See Also:
•

OCITransCommit() for sample code showing the use of simple local
transactions

•

OCITransRollback()

10.2.2 Serializable or Read-Only Local Transactions
Applications requiring serializable or read-only transactions require an additional OCI
OCITransStart() call to start the transaction.
The OCITransStart() call must specify OCI_TRANS_SERIALIZABLE or OCI_TRANS_READONLY,
as appropriate, for the flags parameter. If no flag is specified, the default value is
OCI_TRANS_READWRITE for a standard read/write transaction.
Specifying the read-only option in the OCITransStart() call saves the application from
performing a server round-trip to execute a SET TRANSACTION READ ONLY statement.

See Also:
OCITransStart()

10.2.3 Global Transactions
Global transactions are necessary only in more sophisticated transaction-processing
applications.
This section includes the following topics:
•

Transaction Identifiers

•

Attribute OCI_ATTR_TRANS_NAME

•

Transaction Branches

•

Branch States

•

Detaching and Resuming Branches

•

About Setting the Client Database Name

•

One-Phase Commit Versus Two-Phase Commit

•

Preparing Multiple Branches in a Single Message

10.2.3.1 Transaction Identifiers
Three-tier applications such as transaction processing (TP) monitors create and
manage global transactions.
They supply a global transaction identifier (XID) that a server associates with a local
transaction.

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Levels of Transactional Complexity

A global transaction has one or more branches. Each branch is identified by an XID.
The XID consists of a global transaction identifier (gtrid) and a branch qualifier (bqual).
This structure is based on the standard XA specification.
Table 10-1 provides the structure for one possible XID of 1234.
Table 10-1

Global Transaction Identifier

Component

Value

gtrid

12

bqual

34

gtrid+bqual=XID

1234

The transaction identifier used by OCI transaction calls is set in the OCI_ATTR_XID
attribute of the transaction handle, by using OCIAttrSet(). Alternately, the transaction
can be identified by a name set in the OCI_ATTR_TRANS_NAME attribute.

See Also:
OCIAttrSet()

10.2.3.2 Attribute OCI_ATTR_TRANS_NAME
When this attribute is set in a transaction handle, the length of the name can be at
most 64 bytes.
The formatid of the XID is 0 and the branch qualifier is 0.
When this attribute is retrieved from a transaction handle, the returned transaction
name is the global transaction identifier. The size is the length of the global transaction
identifier.

10.2.3.3 Transaction Branches
Within a single global transaction, Oracle Database supports both tightly coupled and
loosely coupled relationships between a pair of branches.
•

Tightly coupled branches share the same local transaction. The gtrid references a
unique local transaction, and multiple branches point to that same transaction. The
owner of the transaction is the branch that was created first.

•

Loosely coupled branches use different local transactions. The gtrid and bqual
together map to a unique local transaction. Each branch points to a different
transaction.

The flags parameter of OCITransStart() allows applications to pass OCI_TRANS_TIGHT or
OCI_TRANS_LOOSE values to specify the type of coupling.
A session corresponds to a user session, created with OCISessionBegin().
Figure 10-1 illustrates tightly coupled branches within an application. The XIDs of the
two branches (B1 and B2) share the same gtrid, because they are operating on the

10-4

Chapter 10

Levels of Transactional Complexity

same transaction (T), but they have a different bqual, because they are on separate
branches.

Figure 10-1

Multiple Tightly Coupled Branches

S1

S2

B1

B2

Session
Branch
T
Transaction

Figure 10-2 illustrates how a single session operates on different branches. The gtrid
components of the XIDs are different, because they represent separate global
transactions.

Figure 10-2

Session Operating on Multiple Branches

S1

B1

B2

Session
T1

T2

Branch
Transaction

It is possible for a single session to operate on multiple branches that share the same
transaction, but this scenario does not have much practical value.

See Also:
•

OCITransStart() for sample code demonstrating this scenario

•

OCISessionBegin()

10-5

Chapter 10

Levels of Transactional Complexity

10.2.3.4 Branch States
Transaction branches are classified into two states: active branches and inactive
branches.
A branch is active if a server process is executing requests on the branch. A branch is
inactive if no server processes are executing requests in the branch. In this case, no
session is the parent of the branch, and the branch becomes owned by the PMON
process in the server.

10.2.3.5 Detaching and Resuming Branches
A branch becomes inactive when an OCI application detaches it, using the
OCITransDetach() call.

The branch can be made active again by resuming it with a call to OCITransStart() with
the flags parameter set to OCI_TRANS_RESUME.
When an application detaches a branch with OCITransDetach(), it uses the value
specified in the timeout parameter of the OCITransStart() call that created the branch.
The timeout specifies the number of seconds the transaction can remain dormant as a
child of PMON before being deleted.
To resume a branch, the application calls OCITransStart(), specifying the XID of the
branch as an attribute of the transaction handle, OCI_TRANS_RESUME for the flags
parameter, and a different timeout parameter. This timeout value for this call specifies
the length of time that the session waits for the branch to become available if it is
currently in use by another process. If no other processes are accessing the branch, it
can be resumed immediately. A transaction can be resumed by a different process
than the one that detached it, if that process has the same authorization as the one
that detached the transaction.

See Also:
•

OCITransDetach()

•

OCITransStart()

10.2.3.6 About Setting the Client Database Name
The server handle has OCI_ATTR_EXTERNAL_NAME and OCI_ATTR_INTERNAL_NAME attributes.
These attributes set the client database name recorded when performing global
transactions. The name can be used by the database administrator to track
transactions that may be pending in a prepared state because of failures.

Note:
An OCI application sets these attributes, by using OCIAttrSet() before
logging on and using global transactions.

10-6

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Levels of Transactional Complexity

See Also:
OCIAttrSet()

10.2.3.7 One-Phase Commit Versus Two-Phase Commit
Global transactions can be committed in one or two phases.
The simplest situation is when a single transaction is operating against a single
database. In this case, the application can perform a one-phase commit of the
transaction by calling OCITransCommit(), because the default value of the call is for onephase commit.
The situation is more complicated if the application is processing transactions against
multiple Oracle databases. In this case, a two-phase commit is necessary. A twophase commit operation consists of these steps:
1.

Prepare - The application issues an OCITransPrepare() call against each
transaction. Each transaction returns a value indicating whether or not it can
commit its current work (OCI_SUCCESS) or not (OCI_ERROR).

2.

Commit - If each OCITransPrepare() call returns a value of OCI_SUCCESS, the
application can issue an OCITransCommit() call to each transaction. The flags
parameter of the commit call must be explicitly set to OCI_TRANS_TWOPHASE for the
appropriate behavior, because the default for this call is for one-phase commit.

Note:
The OCITransPrepare() call can also return OCI_SUCCESS_WITH_INFO if a
transaction must indicate that it is read-only. Thus a commit is neither
appropriate nor necessary.
An additional call, OCITransForget(), causes a database to "forget" a completed
transaction. This call is for situations in which a problem has occurred that requires
that a two-phase commit be terminated. When an Oracle database receives an
OCITransForget() call, it removes all information about the transaction.

See Also:
•

OCITransCommit()

•

OCITransPrepare()

•

OCITransForget()

10.2.3.8 Preparing Multiple Branches in a Single Message
Sometimes when multiple applications use different branches of a global transaction
against the same Oracle database.

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Before such a transaction can be committed, all branches must be prepared.
Most often, the applications using the branches are responsible for preparing their own
branches. However, some architectures turn this responsibility over to an external
transaction service. This external transaction service must then prepare each branch
of the global transaction. The traditional OCITransPrepare() call is inefficient for this task
as each branch must be individually prepared. The OCITransMultiPrepare() call,
prepares multiple branches involved in the same global transaction in one round-trip.
This call is more efficient and can greatly reduce the number of messages sent from
the client to the server.

See Also:
•

OCITransPrepare()

•

OCITransMultiPrepare()

10.2.4 Transaction Examples
Shows how to use the transaction OCI calls.
Table 10-1 through Table 10-5 illustrate how to use the transaction OCI calls.
They show a series of OCI calls and other actions, along with their resulting behavior.
For simplicity, not all parameters to these calls are listed; rather, it is the flow of calls
that is being demonstrated.
The OCI Action column indicates what the OCI application is doing, or what call it is
making. The XID column lists the transaction identifier, when necessary. The Flags
column lists the values passed in the flags parameter. The Result column describes
the result of the call.

10.2.5 Initialization Parameters
Two initialization parameters relate to the use of global transaction branches and
migratable open connections.
•

TRANSACTIONS - This parameter specifies the maximum number of global transaction

branches in the entire system. In contrast, the maximum number of branches on a
single global transaction is 8.
•

OPEN_LINKS_PER_INSTANCE - This parameter specifies the maximum number of

migratable open connections. Migratable open connections are used by global
transactions to cache connections after committing a transaction. Contrast this
with the OPEN_LINKS parameter, which controls the number of connections from a
session and is not applicable to applications that use global transactions.
This section includes the following topics:
•

Showing Update Successfully, One-Phase Commit

•

Showing Starting a Transaction, Detach, Resume, Prepare, Two-Phase Commit

•

Showing a Read-Only Update Fails

•

Showing Starting a Read-Only Transaction, Select, and Commit

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10.2.5.1 Showing Update Successfully, One-Phase Commit
Lists the steps for a one-phase commit operation.
Table 10-2 lists the steps for a one-phase commit operation.
Table 10-2

One-Phase Commit

Step

OCI Action

XID

Flags

Result

1

OCITransStart()

1234

OCI_TRANS_NEW

Starts new read/write transaction

2

SQL UPDATE

-

-

Update rows

3

OCITransCommit()

-

-

Commit succeeds.

See Also:
•

OCITransStart()

•

OCITransCommit()

10.2.5.2 Showing Starting a Transaction, Detach, Resume, Prepare, TwoPhase Commit
Lists the steps for a two-phase commit operation.
Table 10-3 lists the steps for a two-phase commit operation.
Table 10-3

Two-Phase Commit

Step

OCI Action

XID

Flags

Result

1

OCITransStart()

1234

OCI_TRANS_NEW

Starts new read-only
transaction

2

SQL UPDATE

-

-

Updates rows

3

OCITransDetach()

-

-

Transaction is detached.

4

OCITransStart()

1234

OCI_TRANS_RESUME

Transaction is resumed.

5

SQL UPDATE

-

-

-

6

OCITransPrepare()

-

-

Transaction is prepared for twophase commit.

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Table 10-3

(Cont.) Two-Phase Commit

Step

OCI Action

XID

Flags

Result

7

OCITransCommit()

-

OCI_TRANS_TWOPHASE

Transaction is committed.

In Step 4, the transaction can be resumed by a different process, as long as it had the
same authorization.

See Also:
•

OCITransStart()

•

OCITransDetach()

•

OCITransPrepare()

•

OCITransCommit()

10.2.5.3 Showing a Read-Only Update Fails
Lsts the steps in a failed read-only update operation.
Table 10-4 lists the steps in a failed read-only update operation.
Table 10-4

Read-Only Update Fails

Step

OCI Action

XID

Flags

Result

1

OCITransStart()

1234

OCI_TRANS_NEW |

Starts new read-only transaction.

OCI_TRANS_READONLY
2

SQL UPDATE

-

-

Update fails, because the
transaction is read-only.

3

OCITransCommit()

-

-

Commit has no effect.

See Also:
•

OCITransStart()

•

OCITransCommit()

10.2.5.4 Showing Starting a Read-Only Transaction, Select, and Commit
Lists the steps for a read-only transaction.
Table 10-5 lists the steps for a read-only transaction.

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Table 10-5

Read-Only Transaction

Step

OCI Action

XID

Flags

Result

1

OCITransStart()

1234

OCI_TRANS_NEW |

Starts new read-only transaction

OCI_TRANS_READONLY
2

SQL SELECT

-

-

Queries the database

3

OCITransCommit()

-

-

No effect — transaction is readonly, no changes made

See Also:
•

OCITransStart()

•

OCITransCommit()

10.3 Password and Session Management
OCI can authenticate and maintain multiple users.
This section includes the following topics:
•

OCI Authentication Management

•

OCI Password Management

•

Secure External Password Store

•

OCI Session Management

10.3.1 OCI Authentication Management
The OCISessionBegin() call authenticates a user against the server set in the service
context handle.
It must be the first call for any given server handle. OCISessionBegin() authenticates
the user for access to the Oracle database specified by the server handle and the
service context of the call: after OCIServerAttach() initializes a server handle,
OCISessionBegin() must be called to authenticate the user for that server.
When OCISessionBegin() is called for the first time on a server handle, the user session
may not be created in migratable mode (OCI_MIGRATE). After OCISessionBegin() has
been called for a server handle, the application can call OCISessionBegin() again to
initialize another user session handle with different or the same credentials and
different or the same operation modes. For an application to authenticate a user in
OCI_MIGRATE mode, the service handle must already be associated with a
nonmigratable user handle. The userid of that user handle becomes the ownership ID
of the migratable user session. Every migratable session must have a nonmigratable
parent session.

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•

If OCI_MIGRATE mode is not specified, then the user session context can be used
only with the server handle specified with the OCISessionBegin().

•

If OCI_MIGRATE mode is specified, then the user authentication can be set with other
server handles. However, the user session context can only be used with server
handles that resolve to the same database instance. Security checking is
performed during session switching.

A migratable session can switch to a different server handle only if the ownership ID of
the session matches the userid of a nonmigratable session currently connected to that
same server.
OCI_SYSDBA, OCI_SYSOPER, OCI_SYSBKP, OCI_SYSDGD, OCI_SYSKMT, OCI_SYSRAC, OCI_SYSASM,
and OCI_PRELIM_AUTH settings can only be used with a primary user session context.
For OCI_SYSASM, the SYSASM connection works only to ASM instances (not database

instances).
A migratable session can be switched, or migrated, to a server handle within an
environment represented by an environment handle. It can also migrate or be cloned
to a server handle in another environment in the same process, or in a different
process in a different mode. To perform this migration or cloning, you must do the
following:
1.

Extract the session ID from the session handle using OCI_ATTR_MIGSESSION. This is
an array of bytes that must not be modified by the caller.

2.

Transport this session ID to another process.

3.

In the new environment, create a session handle and set the session ID using
OCI_ATTR_MIGSESSION.

4.

Execute OCISessionBegin(). The resulting session handle is fully authenticated.

To provide credentials for a call to OCISessionBegin(), you must provide a valid user
name and password pair for database authentication in the user session handle
parameter. This involves using OCIAttrSet() to set the OCI_ATTR_USERNAME and
OCI_ATTR_PASSWORD attributes on the user session handle. Then OCISessionBegin() is
called with OCI_CRED_RDBMS.
When the user session handle is terminated using OCISessionEnd(), the user name and
password attributes are changed and thus cannot be reused in a future call to
OCISessionBegin(). They must be reset to new values before the next
OCISessionBegin() call.
Or, you can supply external credentials. No attributes need to be set on the user
session handle before calling OCISessionBegin(). The credential type is OCI_CRED_EXT. If
values have been set for OCI_ATTR_USERNAME and OCI_ATTR_PASSWORD, these are ignored if
OCI_CRED_EXT is used.

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See Also:
•

User Session Handle Attributes for more information about
OCI_ATTR_MIGSESSION

•

OCISessionBegin()

•

OCIServerAttach()

•

OCIAttrSet()

•

OCISessionEnd()

10.3.2 OCI Password Management
The OCIPasswordChange() call enables an application to modify a user's database
password as necessary.
This is particularly useful if a call to OCISessionBegin() returns an error message or
warning indicating that a user's password has expired.
Applications can also use OCIPasswordChange() to establish a user authentication
context and to change the password. If OCIPasswordChange() is called with an
uninitialized service context, it establishes a service context and authenticates the
user's account using the old password, and then changes the password to the new
password. If the OCI_AUTH flag is set, the call leaves the user session initialized.
Otherwise, the user session is cleared.
If the service context passed to OCIPasswordChange() is already initialized, then
OCIPasswordChange() authenticates the given account using the old password and
changes the password to the new password. In this case, no matter how the flag is
set, the user session remains initialized.

See Also:
•

OCIPasswordChange()

•

OCISessionBegin()

10.3.3 Secure External Password Store
For large-scale deployments where applications use password credentials to connect
to databases, it is possible to store such credentials in a client-side Oracle wallet.
An Oracle wallet is a secure software container that is used to store authentication and
signing credentials.
Storing database password credentials in a client-side Oracle wallet eliminates the
need to embed user names and passwords in application code, batch jobs, or scripts.
This reduces the risk of exposing passwords in the clear in scripts and application
code, and simplifies maintenance because you need not change your code each time

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user names and passwords change. In addition, not having to change application code
makes it easier to enforce password management policies for these user accounts.
When you configure a client to use the external password store, applications can use
the following syntax to connect to databases that use password authentication:
CONNECT /@database_alias

Note that you need not specify database login credentials in this CONNECT statement.
Instead your system looks for database login credentials in the client wallet.

See Also:
Oracle Database Administrator’s Guide for information about configuring
your client to use the secure external password store

10.3.4 OCI Session Management
Transaction servers that actively balance user load by multiplexing user sessions over
a few server connections must group these connections into a server group.
Oracle Database uses server groups to identify these connections so that sessions
can be managed effectively and securely.
The attribute OCI_ATTR_SERVER_GROUP must be defined to specify the server group name
by using the OCIAttrSet() call, as shown in Example 10-1.
The server group name is an alphanumeric string not exceeding 30 characters. This
attribute can only be set after calling OCIServerAttach(). OCI_ATTR_SERVER_GROUP attribute
must be set in the server context before creating the first nonmigratable session that
uses that context. After the session is created successfully and the connection to the
server is established, the server group name cannot be changed.
All migratable sessions created on servers within a server group can only migrate to
other servers in the same server group. Servers that terminate are removed from the
server group. New servers can be created within an existing server group at any time.
The use of server groups is optional. If no server group is specified, the server is
created in a server group called DEFAULT.
The owner of the first nonmigratable session created in a nondefault server group
becomes the owner of the server group. All subsequent nonmigratable sessions for
any server in this server group must be created by the owner of the server group.
The server group feature is useful when dedicated servers are used. It has no effect
on shared servers. All shared servers effectively belong to the server group DEFAULT.
Example 10-1 Defining the OCI_ATTR_SERVER_GROUP Attribute to Pass the
Server Group Name
OCIAttrSet ((void *) srvhp, (ub4) OCI_HTYPE_SERVER, (void *) group_name,
(ub4) strlen ((CONST char *) group_name),
(ub4) OCI_ATTR_SERVER_GROUP, errhp);

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See Also:
•

Server Handle Attributes for more information about
OCI_ATTR_SERVER_GROUP attribute

•

OCIAttrSet()

•

OCIServerAttach()

10.4 Middle-Tier Applications in OCI
A middle-tier application receives requests from browser clients.
The application determines database access and whether to generate an HTML page.
Applications can have multiple lightweight user sessions within a single database
session. These lightweight sessions allow each user to be authenticated without the
overhead of a separate database connection, and they preserve the identity of the real
user through the middle tier.
As long as the client authenticates itself with the middle tier, and the middle tier
authenticates itself with the database, and the middle tier is authorized to act on behalf
of the client by the administrator, client identities can be maintained all the way into the
database without compromising the security of the client.
The design of a secure three-tier architecture is developed around a set of three trust
zones.
The first is the client trust zone. Clients connecting to a web application server are
authenticated by the middle tier using any means: password, cryptographic token, or
another. This method can be entirely different from the method used to establish the
other trust zones.
The second trust zone is the application server. The data server verifies the identity of
the application server and trusts it to pass the correct identity of the client.
The third trust zone is the data server interaction with the authorization server to obtain
the roles assigned to the client and the application server.
The application server creates a primary session for itself after it connects to a server.
It authenticates itself in the normal manner to the database, creating the application
server trust zone. The application server identity is now well known and trusted by the
data server.
When the application verifies the identity of a client connecting to the application
server, it creates the first trust zone. The application server now needs a session
handle for the client so that it can service client requests. The middle-tier process
allocates a session handle and then sets the following attributes of the client using
OCIAttrSet():
•

OCI_ATTR_USERNAME sets the database user name of the client.

•

OCI_ATTR_PROXY_CREDENTIALS indicates the authenticated application making the

proxy request.
To specify a list of roles activated after the application server connects as the client, it
can call OCIAttrSet() with the attribute OCI_ATTR_INITIAL_CLIENT_ROLES and an array of

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strings that contains the list of roles before the OCISessionBegin() call. Then the role is
established and proxy capability is verified in one round-trip. If the application server is
not allowed to act on behalf of the client, or if the application server is not allowed to
activate the specified roles, the OCISessionBegin() call fails.
This section includes the following topic: OCI Attributes for Middle-Tier Applications.

See Also:
•

OCIAttrSet()

•

OCISessionBegin()

10.4.1 OCI Attributes for Middle-Tier Applications
The following attributes enable you to specify the external name and initial privileges of
a client.
These credentials are used by applications as alternative means of identifying or
authenticating the client.
These attributes include:
•

OCI_CRED_PROXY

•

OCI_ATTR_PROXY_CREDENTIALS

•

OCI_ATTR_DISTINGUISHED_NAME

•

OCI_ATTR_CERTIFICATE

•

OCI_ATTR_INITIAL_CLIENT_ROLES

•

OCI_ATTR_CLIENT_IDENTIFIER

•

OCI_ATTR_PASSWORD

10.4.1.1 OCI_CRED_PROXY
Use OCI_CRED_PROXY as the value passed in the credt parameter of OCISessionBegin().
When an application server starts a session on behalf of a client, use OCI_CRED_PROXY
as the value passed in the credt parameter of OCISessionBegin() rather than
OCI_CRED_RDBMS (database user name and password required) or OCI_CRED_EXT
(externally provided credentials).

See Also:
OCISessionBegin()

10.4.1.2 OCI_ATTR_PROXY_CREDENTIALS
Use the OCI_ATTR_PROXY_CREDENTIALS attribute to specify the credentials of the
application server in client authentication.

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You can code the following declarations and OCIAttrSet() call, as shown in
Example 10-2.
Example 10-2 Defining the OCI_ATTR_PROXY_CREDENTIALS Attribute to
Specify the Credentials of the Application Server for Client Authentication
OCISession *session_handle;
OCISvcCtx *application_server_session_handle;
OCIError *error_handle;
...
OCIAttrSet((void *)session_handle, (ub4) OCI_HTYPE_SESSION,
(void *)application_server_session_handle, (ub4) 0,
OCI_ATTR_PROXY_CREDENTIALS, error_handle);

See Also:
OCIAttrSet()

10.4.1.3 OCI_ATTR_DISTINGUISHED_NAME
Use OCI_ATTR_DISTINGUISHED_NAME to pass the distinguished name of the client.
Your applications can use the distinguished name contained within a X.509 certificate
as the login name of the client, instead of the database user name.
To pass the distinguished name of the client, the middle-tier server calls OCIAttrSet(),
passing OCI_ATTR_DISTINGUISHED_NAME, as shown in Example 10-3.
Example 10-3 Defining the OCI_ATTR_DISTINGUISHED_NAME Attribute to
Pass the Distinguished Name of the Client
/* Declarations */
...
OCIAttrSet((void *)session_handle, (ub4) OCI_HTYPE_SESSION,
(void *)distinguished_name, (ub4) 0,
OCI_ATTR_DISTINGUISHED_NAME, error_handle);

See Also:
OCIAttrSet()

10.4.1.4 OCI_ATTR_CERTIFICATE
Certificate-based proxy authentication using OCI_ATTR_CERTIFICATE will not be
supported in future Oracle Database releases.
Use OCI_ATTR_DISTINGUISHED_NAME or OCI_ATTR_USERNAME attribute instead. This method
of authentication is similar to the use of the distinguished name. The entire X.509
certificate is passed by the middle-tier server to the database.
To pass over the entire certificate, the middle tier calls OCIAttrSet(), passing
OCI_ATTR_CERTIFICATE, as shown in Example 10-4.

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Example 10-4 Defining the OCI_ATTR_CERTIFICATE Attribute to Pass the
Entire X.509 Certificate
OCIAttrSet((void *)session_handle, (ub4) OCI_HTYPE_SESSION,
(void *)certificate, ub4 certificate_length,
OCI_ATTR_CERTIFICATE, error_handle);

See Also:
OCIAttrSet()

10.4.1.5 OCI_ATTR_INITIAL_CLIENT_ROLES
Use the OCI_ATTR_INITIAL_CLIENT_ROLES attribute to specify the roles the client is to
possess when the application server connects to the Oracle database.
To enable a set of roles, the function OCIAttrSet() is called with the attribute, an array
of NULL-terminated strings, and the number of strings in the array, as shown in
Example 10-5.
Example 10-5 Defining the OCI_ATTR_INITIAL_CLIENT_ROLES Attribute to
Pass the Client Roles
OCIAttrSet((void *)session_handle, (ub4) OCI_HTYPE_SESSION,
(void *)role_array, (ub4) number_of_strings,
OCI_ATTR_INITIAL_CLIENT_ROLES, error_handle);

See Also:
OCIAttrSet()

10.4.1.6 OCI_ATTR_CLIENT_IDENTIFIER
Use OCI_ATTR_CLIENT_IDENTIFIER on the middle tier to track end-user identity.
Many middle-tier applications connect to the database as an application, and rely on
the middle tier to track end-user identity. To integrate tracking of the identity of these
users in various database components, the database client can set the
CLIENT_IDENTIFIER (a predefined attribute from the application context namespace
USERENV) in the session handle at any time. Use the OCI attribute
OCI_ATTR_CLIENT_IDENTIFIER in the call to OCIAttrSet(), as shown in Example 10-6. On
the next request to the server, the information is propagated and stored in the server
session.
The CLIENT_IDENTIFIER, which can also be set using the DBMS_SESSION.SET_IDENTIFIER
procedure, is automatically truncated if the supplied input is more than 64 bytes
because the maximum size for the client id is 64 bytes.
OCI_ATTR_CLIENT_IDENTIFIER can also be used in conjunction with the global application
context to restrict availability of the context to the selected identity of these users.

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When a client has multiple sessions, execute OCIAttrSet() for each session using the
same client identifier. OCIAttrSet() must be executed manually for sessions that are
reestablished through transparent application failover (TAF).
The client identifier is found in V$SESSION as a CLIENT_IDENTIFIER column or through the
system context with this SQL statement:
SELECT SYS_CONTEXT('userenv', 'client_identifier') FROM DUAL;

Example 10-6 Defining the OCI_ATTR_CLIENT_IDENTIFIER Attribute to Pass
the End-User Identity
OCIAttrSet((void *)session_handle, (ub4) OCI_HTYPE_SESSION,
(void *)"janedoe", (ub4)strlen("janedoe"),
OCI_ATTR_CLIENT_IDENTIFIER, error_handle);

See Also:
•

Oracle Database Security Guide the section about preserving user
identity in multi-tiered environments"

•

Transparent Application Failover in OCI

•

OCIAttrSet()

10.4.1.7 OCI_ATTR_PASSWORD
To use the password of the client for validation on the middle-tier, the application
server can use the existing attribute OCI_ATTR_PASSWORD with the client’s authentication
data.
A middle tier can ask the database server to authenticate a client on its behalf by
validating the password of the client rather than doing the authentication itself.
Although it appears that this is the same as a client/server connection, the client does
not have to have Oracle Database software installed on the client's system to be able
to perform database operations. To use the password of the client, the application
server supplies OCIAttrSet() with the authentication data, using the existing attribute
OCI_ATTR_PASSWORD, as shown in Example 10-7.
Example 10-8 shows OCI attributes that enable you to specify the external name and
initial privileges of a client. These credentials are used by OCI applications as
alternative means of identifying or authenticating the client.
Example 10-7 Defining the OCI_ATTR_PASSWORD Attribute to Pass the
Password for Validation
OCIAttrSet((void *)session_handle, (ub4) OCI_HTYPE_SESSION, (void *)password,
(ub4)0, OCI_ATTR_PASSWORD, error_handle);

Example 10-8 OCI Attributes That Let You Specify the External Name and Initial
Privileges of a Client
...
*OCIEnv *environment_handle;
OCIServer *data_server_handle;
OCIError *error_handle;
OCISvcCtx *application_server_service_handle;

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OraText *client_roles[2];
OCISession *first_client_session_handle, second_client_session_handle;
...
/*
** General initialization and allocation of contexts.
*/
(void) OCIInitialize((ub4) OCI_DEFAULT, (void *)0,
(void * (*)(void *, size_t)) 0,
(void * (*)(void *, void *, size_t))0,
(void (*)(void *, void *)) 0 );
(void) OCIEnvInit( (OCIEnv **) &environment_handle, OCI_DEFAULT, (size_t) 0,
(void **) 0 );
(void) OCIHandleAlloc( (void *) environment_handle, (void **) &error_handle,
OCI_HTYPE_ERROR, (size_t) 0, (void **) 0);
/*
** Allocate and initialize the server and service contexts used by the
** application server.
*/
(void) OCIHandleAlloc( (void *) environment_handle,
(void **)&data_server_handle, OCI_HTYPE_SERVER, (size_t) 0, (void **) 0);
(void) OCIHandleAlloc( (void *) environment_handle, (void **)
&application_server_service_handle, OCI_HTYPE_SVCCTX, (size_t) 0,
(void **) 0);
(void) OCIAttrSet((void *) application_server_service_handle,
OCI_HTYPE_SVCCTX, (void *) data_server_handle, (ub4) 0, OCI_ATTR_SERVER,
error_handle);
/*
** Authenticate the application server. In this case, external authentication is
** being used.
*/
(void) OCIHandleAlloc((void *) environment_handle,
(void **)&application_server_session_handle, (ub4) OCI_HTYPE_SESSION,
(size_t) 0, (void **) 0);
checkerr(error_handle, OCISessionBegin(application_server_service_handle,
error_handle, application_server_session_handle, OCI_CRED_EXT,
OCI_DEFAULT));
/*
** Authenticate the first client.
** Note that no password is specified by the
** application server for the client as it is trusted.
*/
(void) OCIHandleAlloc((void *) environment_handle,
(void **)&first_client_session_handle, (ub4) OCI_HTYPE_SESSION,
(size_t) 0,(void **) 0);
(void) OCIAttrSet((void *) first_client_session_handle,
(ub4) OCI_HTYPE_SESSION, (void *) "jeff", (ub4) strlen("jeff"),
OCI_ATTR_USERNAME, error_handle);
/*
** In place of specifying a password, pass the session handle of the application
** server instead.
*/
(void) OCIAttrSet((void *) first_client_session_handle,
(ub4) OCI_HTYPE_SESSION, (void *) application_server_session_handle,
(ub4) 0, OCI_ATTR_PROXY_CREDENTIALS, error_handle);
(void) OCIAttrSet((void *) first_client_session_handle,
(ub4) OCI_HTYPE_SESSION, (void *) "jeff@VeryBigBank.com",

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(ub4) strlen("jeff@VeryBigBank.com"), OCI_ATTR_EXTERNAL_NAME,
error_handle);
/*
** Establish the roles that the application server can use as the client.
*/
client_roles[0] = (OraText *) "TELLER";
client_roles[1] = (OraText *) "SUPERVISOR";
(void) OCIAttrSet((void *) first_client_session_handle,
OCI_ATTR_INITIAL_CLIENT_ROLES, error_handle);
checkerr(error_handle, OCISessionBegin(application_server_service_handle,
error_handle, first_client_session_handle, OCI_CRED_PROXY, OCI_DEFAULT));
/*
** To start a session as another client, the application server does the
** following.
** This code is unchanged from the current way of doing session switching.
*/
(void) OCIHandleAlloc((void *) environment_handle,
(void **)&second_client_session_handle, (ub4) OCI_HTYPE_SESSION,
(size_t) 0, (void **) 0);
(void) OCIAttrSet((void *) second_client_session_handle,
(ub4) OCI_HTYPE_SESSION, (void *) "mutt", (ub4) strlen("mutt"),
OCI_ATTR_USERNAME, error_handle);
(void) OCIAttrSet((void *) second_client_session_handle,
(ub4) OCI_HTYPE_SESSION, (void *) application_server_session_handle,
(ub4) 0, OCI_ATTR_PROXY_CREDENTIALS, error_handle);
(void) OCIAttrSet((void *) second_client_session_handle,
(ub4) OCI_HTYPE_SESSION, (void *) "mutt@VeryBigBank.com",
(ub4) strlen("mutt@VeryBigBank.com"), OCI_ATTR_EXTERNAL_NAME,
error_handle);
/*
** Note that the application server has not specified any initial roles to have
** as the second client.
*/
checkerr(error_handle, OCISessionBegin(application_server_service_handle,
error_handle, second_client_session_handle, OCI_CRED_PROXY, OCI_DEFAULT));
/*
** To switch to the first user, the application server applies the session
** handle obtained by the first
** OCISessionBegin() call. This is the same as is currently done.
*/
(void) OCIAttrSet((void *)application_server_service_handle,
(ub4) OCI_HTYPE_SVCCTX, (void *)first_client_session_handle,
(ub4)0, (ub4)OCI_ATTR_SESSION, error_handle);
/*
** After doing some operations, the application server can switch to
** the second client. That
** is be done by the following call:
*/
(void) OCIAttrSet((void *)application_server_service_handle,
(ub4) OCI_HTYPE_SVCCTX,
(void *)second_client_session_handle, (ub4)0, (ub4)OCI_ATTR_SESSION,
error_handle);
/*
** and then do operations as that client
*/
...

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Chapter 10

Externally Initialized Context in OCI

See Also:
•

User Session Handle Attributes

•

OCIAttrSet()

10.5 Externally Initialized Context in OCI
An externally initialized context is an application context where attributes can be
initialized from OCI. Use the SQL statement CREATE CONTEXT to create a context
namespace in the server with the option INITIALIZED EXTERNALLY.
Then, you can initialize an OCI interface when establishing a session using
OCIAttrSet() and OCISessionBegin(). Issue subsequent commands to write to any
attributes inside the namespace only with the PL/SQL package designated in the
CREATE CONTEXT statement.
You can set default values and other session attributes through the OCISessionBegin()
call, thus reducing server round-trips.
This section includes the following topics:
•

Externally Initialized Context in OCI

•

End-to-End Application Tracing

•

Using OCISessionBegin() with an Externally Initialized Context

See Also:
•

Oracle Database Security Guide the chapter about managing security for
application developers

•

Oracle Database SQL Language Reference the CREATE CONTEXT statement
and the SYS_CONTEXT function

•

OCIAttrSet()

•

OCISessionBegin()

10.5.1 Externally Initialized Context Attributes in OCI
The client applications you develop can set application contexts explicitly in the
session handle before authentication.
To do this, use the following attributes in OCI functions:
•

OCI_ATTR_APPCTX_SIZE

•

OCI_ATTR_APPCTX_LIST

•

Session Handle Attributes Used to Set an Externally Initialized Context

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Externally Initialized Context in OCI

10.5.1.1 OCI_ATTR_APPCTX_SIZE
Use the OCI_ATTR_APPCTX_SIZE attribute to initialize the context array size with the
desired number of context attributes in the OCIAttrSet() call.
This is shown in Example 10-9.
Example 10-9 Defining the OCI_ATTR_APPCTX_SIZE Attribute to Initialize the
Context Array Size with the Desired Number of Context Attributes
OCIAttrSet(session, (ub4) OCI_HTYPE_SESSION,
(void *)&size, (ub4)0, OCI_ATTR_APPCTX_SIZE, error_handle);

See Also:
OCIAttrSet()

10.5.1.2 OCI_ATTR_APPCTX_LIST
Use the OCI_ATTR_APPCTX_LIST attribute to get a handle on the application context list
descriptor for the session in the OCIAttrGet() call.
This is shown in Example 10-10. (The parameter ctxl_desc must be of data type
OCIParam *).

Example 10-11 shows how to use the application context list descriptor to obtain an
individual descriptor for the i-th application context in a call to OCIParamGet().
Example 10-10 Using the OCI_ATTR_APPCTX_LIST Attribute to Get a Handle
on the Application Context List Descriptor for the Session
OCIAttrGet(session, (ub4) OCI_HTYPE_SESSION,
(void *)&ctxl_desc, (ub4)0, OCI_ATTR_APPCTX_LIST, error_handle);

Example 10-11 Calling OCIParamGet() to Obtain an Individual Descriptor for
the i-th Application Context Using the Application Context List Descriptor
OCIParamGet(ctxl_desc, OCI_DTYPE_PARAM, error_handle,(void **)&ctx_desc, i);

See Also:
•

OCIAttrGet()

•

OCIParamGet()

10.5.1.3 Session Handle Attributes Used to Set an Externally Initialized Context
Shows how to set the appropriate session handle attributes values for the application
context.
Set the appropriate values of the application context using these attributes:

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Chapter 10

Externally Initialized Context in OCI

•

OCI_ATTR_APPCTX_NAME to set the namespace of the context, which must be a valid

SQL identifier.
•

OCI_ATTR_APPCTX_ATTR to set an attribute name in the given context, a non-case-

sensitive string of up to 30 bytes.
•

OCI_ATTR_APPCTX_VALUE to set the value of an attribute in the given context.

Each namespace can have many attributes, each of which has one value.
Example 10-12 shows the calls you can use to set them.
Note that only character type is supported, because application context operations are
based on the VARCHAR2 data type.
Example 10-12
Context

Defining Session Handle Attributes to Set Externally Initialized

OCIAttrSet(ctx_desc, OCI_DTYPE_PARAM,
(void *)ctx_name, sizeof(ctx_name), OCI_ATTR_APPCTX_NAME, error_handle);
OCIAttrSet(ctx_desc, OCI_DTYPE_PARAM,
(void *)attr_name, sizeof(attr_name), OCI_ATTR_APPCTX_ATTR, error_handle);
OCIAttrSet(ctx_desc, OCI_DTYPE_PARAM,
(void *)value, sizeof(value), OCI_ATTR_APPCTX_VALUE, error_handle);

See Also:
User Session Handle Attributes

10.5.2 End-to-End Application Tracing
Use the following attributes to measure server call time, not including server roundtrips.
These attributes can also be set by using the PL/SQL package DBMS_APPLICATION_INFO,
which incurs one round-trip to the server. Using OCI to set the attributes does not incur
a round-trip.
This section includes the following topics:
•

OCI_ATTR_COLLECT_CALL_TIME

•

OCI_ATTR_CALL_TIME

•

Attributes for End-to-End Application Tracing

10.5.2.1 OCI_ATTR_COLLECT_CALL_TIME
Use the attribute OCI_ATTR_COLLECT_CALL_TIME and set the value to TRUE to enable the
server to measure each call time.
Set a boolean variable to TRUE or FALSE. After you set the OCI_ATTR_COLLECT_CALL_TIME
attribute by calling OCIAttrSet(), the server measures each call time. All server times
between setting the variable to TRUE and setting it to FALSE are measured.

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Chapter 10

Externally Initialized Context in OCI

See Also:
OCIAttrSet()

10.5.2.2 OCI_ATTR_CALL_TIME
Use the attribute OCI_ATTR_CALL_TIME to get the elapsed time of the last server call.
The elapsed time, in microseconds, of the last server call is returned in a ub8 variable
by calling OCIAttrGet() with the OCI_ATTR_CALL_TIME attribute. Example 10-13 shows
how to do this in a code fragment.
Example 10-13 Using the OCI_ATTR_CALL_TIME Attribute to Get the Elapsed
Time of the Last Server Call
boolean enable_call_time;
ub8 call_time;
...
enable_call_time = TRUE;
OCIAttrSet(session, OCI_HTYPE_SESSION, (void *)&enable_call_time,
(ub4)0, OCI_ATTR_COLLECT_CALL_TIME,
(OCIError *)error_handle);
OCIStmtExecute(...);
OCIAttrGet(session, OCI_HTYPE_SESSION, (void *)&call_time,
(ub4)0, OCI_ATTR_CALL_TIME,
(OCIError *)error_handle);
...

See Also:
OCIAttrGet()

10.5.2.3 Attributes for End-to-End Application Tracing
Use these attributes for monitoring, tracing, and debugging applications.
Set these attributes for monitoring, tracing, and debugging applications:
•

OCI_ATTR_MODULE - Name of the current module in the client application.

•

OCI_ATTR_ACTION - Name of the current action within the current module. Set to NULL

if you do not want to specify an action.
•

OCI_ATTR_DBOP - Name of the database operation set by the client application to be
monitored in the database. Set to NULL if you want to end monitoring the current

running database operation.
•

OCI_ATTR_CLIENT_INFO - Client application additional information.

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Chapter 10

Externally Initialized Context in OCI

See Also:
User Session Handle Attributes
Monitoring Database Operations in Oracle Database SQL Tuning Guide
Monitoring Real-Time Database Performance in Oracle Database 2 Day
+ Performance Tuning Guide

10.5.3 Using OCISessionBegin() with an Externally Initialized Context
When you call OCISessionBegin(), the context set in the session handle is pushed to
the server.
No additional contexts are propagated to the server session. Example 10-14 illustrates
the use of these calls and attributes.
Example 10-14
#include
#include
#include
#include

Using OCISessionBegin() with an Externally Initialized Context






static OraText *username = (OraText *) "HR";
static OraText *password = (OraText *) "HR";
static OCIEnv *envhp;
static OCIError *errhp;
int main(/*_ int argc, char *argv[] _*/);
static sword status;
int main(argc, argv)
int argc;
char *argv[];
{
OCISession *authp = (OCISession *) 0;
OCIServer *srvhp;
OCISvcCtx *svchp;
OCIDefine *defnp = (OCIDefine *) 0;
void
*parmdp;
ub4
ctxsize;
OCIParam *ctxldesc;
OCIParam *ctxedesc;
OCIEnvCreate(&envhp, OCI_DEFAULT, (void *)0, 0, 0, 0,
(size_t)0, (void *)0);
(void) OCIHandleAlloc( (void *) envhp, (void **) &errhp, OCI_HTYPE_ERROR,
(size_t) 0, (void **) 0);
/* server contexts */
(void) OCIHandleAlloc( (void *) envhp, (void **) &srvhp, OCI_HTYPE_SERVER,
(size_t) 0, (void **) 0);

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Chapter 10

Externally Initialized Context in OCI

(void) OCIHandleAlloc( (void *) envhp, (void **) &svchp, OCI_HTYPE_SVCCTX,
(size_t) 0, (void **) 0);
(void) OCIServerAttach( srvhp, errhp, (OraText *)"", strlen(""), 0);
/* set attribute server context in the service context */
(void) OCIAttrSet( (void *) svchp, OCI_HTYPE_SVCCTX, (void *)srvhp,
(ub4) 0, OCI_ATTR_SERVER, (OCIError *) errhp);
(void) OCIHandleAlloc((void *) envhp, (void **)&authp,
(ub4) OCI_HTYPE_SESSION, (size_t) 0, (void **) 0);
/****************************************/
/* set app ctx size to 2 because you want to set up 2 application contexts */
ctxsize = 2;
/* set up app ctx buffer */
(void) OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_SESSION,
(void *) &ctxsize, (ub4) 0,
(ub4) OCI_ATTR_APPCTX_SIZE, errhp);
/* retrieve the list descriptor */
(void) OCIAttrGet((void *)authp, (ub4) OCI_HTYPE_SESSION,
(void *)&ctxldesc, 0, OCI_ATTR_APPCTX_LIST, errhp );
/* retrieve the 1st ctx element descriptor */
(void) OCIParamGet(ctxldesc, OCI_DTYPE_PARAM, errhp, (void**)&ctxedesc, 1);
(void) OCIAttrSet((void *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
(void *) "HR", (ub4) strlen((char *)"HR"),
(ub4) OCI_ATTR_APPCTX_NAME, errhp);
(void) OCIAttrSet((void *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
(void *) "ATTR1", (ub4) strlen((char *)"ATTR1"),
(ub4) OCI_ATTR_APPCTX_ATTR, errhp);
(void) OCIAttrSet((void *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
(void *) "VALUE1", (ub4) strlen((char *)"VALUE1"),
(ub4) OCI_ATTR_APPCTX_VALUE, errhp);
/* set second context */
(void) OCIParamGet(ctxldesc, OCI_DTYPE_PARAM, errhp, (void**)&ctxedesc, 2);
(void) OCIAttrSet((void *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
(void *) "HR", (ub4) strlen((char *)"HR"),
(ub4) OCI_ATTR_APPCTX_NAME, errhp);
(void) OCIAttrSet((void *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
(void *) "ATTR2", (ub4) strlen((char *)"ATTR2"),
(ub4) OCI_ATTR_APPCTX_ATTR, errhp);
(void) OCIAttrSet((void *) ctxedesc, (ub4) OCI_DTYPE_PARAM,
(void *) "VALUE2", (ub4) strlen((char *)"VALUE2"),
(ub4) OCI_ATTR_APPCTX_VALUE, errhp);
/****************************************/
(void) OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_SESSION,
(void *) username, (ub4) strlen((char *)username),
(ub4) OCI_ATTR_USERNAME, errhp);
(void) OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_SESSION,
(void *) password, (ub4) strlen((char *)password),
(ub4) OCI_ATTR_PASSWORD, errhp);

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Chapter 10

Client Application Context

OCISessionBegin ( svchp, errhp, authp, OCI_CRED_EXT, (ub4) OCI_DEFAULT);
}

See Also:
OCISessionBegin()

10.6 Client Application Context
Application context enables database clients (such as mid-tier applications) to set and
send arbitrary session data to the server with each executed statement in only one
round-trip.
The server stores this data in the session context before statement execution, from
which it can be used to restrict queries or DML operations. All database features such
as views, triggers, virtual private database (VPD) policies, or PL/SQL stored
procedures can use session data to constrain their operations.
A public writable namespace, nm, is created:
CREATE CONTEXT nm USING hr.package1;

To modify the data grouped in that namespace, users must execute the designated
PL/SQL package, hr.package1. However, no privilege is needed to query this
information in a user session.
The variable length application context data that is stored in the user session is in the
form of an attribute and value pair grouped under the context namespace.
For example, if you want a human resources application to store an end-user's
responsibility information in the user session, then it could create an nm namespace
and an attribute called "responsibility" that can be assigned a value such as "manager"
or "accountant". This is referred to as the set operation in this document.
If you want the application to clear the value of the "responsibility" attribute in the nm
namespace, then it could set it to NULL or an empty string. This is referred to as the
clear operation in this document.
To clear all information in the nm namespace, the application can send the namespace
information as a part of the clear-all operation to the server. This is referred to as the
clear-all operation in a namespace in this document.
If there is no package security defined for a namespace, then this namespace is
deemed to be a client namespace, and any OCI client can transport data for that
namespace to the server. No privilege or package security check is done.
Network transport of application context data is done in a single round-trip to the
server.
This section includes the following topics:
•

Using Multiple SET Operations

•

Using CLEAR-ALL Operations Between SET Operations

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Chapter 10

Client Application Context

•

Network Transport and PL/SQL on Client Namespace

10.6.1 Using Multiple SET Operations
Use the OCIAppCtxSet() function to perform a series of set operations on the
"responsibility" attribute in the CLIENTCONTEXT namespace.
When this information is sent to the server, the latest value prevails for that particular
attribute in a namespace. To change the value of the "responsibility" attribute in the
CLIENTCONTEXT namespace from "manager" to "vp", use the code fragment shown in
Example 10-15, on the client side. When this information is transported to the server,
the server shows the latest value "vp" for the "responsibility" attribute in the
CLIENTCONTEXT namespace.
You can clear specific attribute information in a client namespace. This can be done by
setting the value of an attribute to NULL or to an empty string, as shown in
Example 10-16 using the OCIAppCtxSet() function.
Example 10-15 Changing the "responsibility" Attribute Value in the
CLIENTCONTEXT Namespace
err = OCIAppCtxSet((void *) sesshndl,(void *)"CLIENTCONTEXT",(ub4) 13,
(void *)"responsibility", 14
(void *)"manager", 7, errhp, OCI_DEFAULT);
err = OCIAppCtxSet((void *) sesshndl, (void*)"CLIENTCONTEXT", 13,
(void *)"responsibility", 14,(void *)"vp",2, errhp,
OCI_DEFAULT);

Example 10-16
Namespace

Two Ways to Clear Specific Attribute Information in a Client

(void) OCIAppCtxSet((void *) sesshndl, (void *)"CLIENTCONTEXT", 13,
(void *)"responsibility", 14, (void *)0, 0,errhp,
OCI_DEFAULT);
(void) OCIAppCtxSet((void *) sesshndl, (void *)"CLIENTCONTEXT", 13
(void *)"responsibility", 14, (void *)"", 0,errhp,
OCI_DEFAULT);

See Also:
OCIAppCtxSet()

10.6.2 Using CLEAR-ALL Operations Between SET Operations
You can clear all the context information in a specific client namespace, using the
OCIAppCtxClearAll() function, and it will also be cleared on the server-side user
session, during the next network transport.
If the client application performs a clear-all operation in a namespace after several set
operations, then values of all attributes in that namespace that were set before this
clear-all operation are cleaned up on the client side and the server side. Only the set
operations that were done after the clear-all operation are reflected on the server side.
On the client side, the code appears, as shown in Example 10-17.

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Chapter 10

Client Application Context

The clear-all operation clears any information set by earlier operations in the
namespace CLIENTCONTEXT: "responsibility" = "manager" is removed. The information
that was set subsequently will not be reflected on the server side.
Example 10-17
Namespace

Clearing All the Context Information in a Specific Client

err = OCIAppCtxSet((void *) sesshndl,(void *)"CLIENTCONTEXT", 13,
(void *)"responsibility", 14,
(void *)"manager", 7,errhp, OCI_DEFAULT);
err = OCIAppCtxClearAll((void *) sesshndl, (void *)"CLIENTCONTEXT", 13, errhp,
OCI_DEFAULT);
err = OCIAppCtxSet((void *) sesshndl, (void*)"CLIENTCONTEXT",13
(void *)"office",6, (void *)"2op123", 5, errhp, OCI_DEFAULT);

See Also:
OCIAppCtxClearAll()

10.6.3 Network Transport and PL/SQL on Client Namespace
It is possible that an application could send application context information on an
OCIStmtExecute() call to the server, and also attempt to change the same context
information during that call by executing the DBMS_SESSION package.
In general, on the server side, the transported information is processed first and the
main call is processed later. This behavior applies to the application context network
transports as well.
If they are both writing to the same client namespace and attribute set, then the main
call's information overwrites the information set provided by the fast network transport
mechanism. If an error occurs in the network transport call, the main call is not
executed.
However, an error in the main call does not affect the processing of the network
transport call. Once the network transport call is processed, then there is no way to
undo it. When the error is reported to the caller (by an OCI function), it is reported as a
generic ORA error. Currently, there is no easy way to distinguish an error in the
network transport call from an error in the main call. The client should not assume that
an error from the main call will undo the round-trip network processing and should
implement appropriate exception-handling mechanisms to prevent any
inconsistencies.

See Also:
•

OCIStmtExecute()

•

OCIAppCtxClearAll()

•

OCIAppCtxSet()

10-30

Chapter 10

Using Edition-Based Redefinition

10.7 Using Edition-Based Redefinition
An edition provides a staging area where "editionable" objects changed by an
application patch can be installed and executed while the existing application is still
available.
You can specify an edition other than the database default by setting the attribute
OCI_ATTR_EDITION at session initiation time. The application can call OCIAttrSet()

specifying this attribute name and the edition as the value, as shown in
Example 10-18.
If OCIAttrSet() is not called, the value of the edition name is obtained from the
operating system environment variable ORA_EDITION. If that variable is not set, then the
value of OCI_ATTR_EDITION is the empty string. If a nonempty value was specified, then
the server sets the specified edition for the session, or the session uses the database
default edition. The server then checks that the user has the USE privilege on the
edition. If not, then the connect fails. If a nonexistent edition name was specified, then
an error is returned.
Example 10-18

Calling OCIAttrSet() to Set the OCI_ATTR_EDITION Attribute

static void workerFunction()
{
OCISvcCtx *svchp = (OCISvcCtx *) 0;
OCIAuthInfo *authp = (OCIAuthInfo *)0;
sword err;
err = OCIHandleAlloc((void *) envhp, (void **)&authp,
(ub4) OCI_HTYPE_AUTHINFO,
(size_t) 0, (void **) 0);
if (err)
checkerr(errhp, err);
checkerr(errhp, OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_AUTHINFO,
(void *) username, (ub4) strlen((char *)username),
(ub4) OCI_ATTR_USERNAME, errhp));
checkerr(errhp,OCIAttrSet((void *) authp, (ub4) OCI_HTYPE_AUTHINFO,
(void *) password, (ub4) strlen((char *)password),
(ub4) OCI_ATTR_PASSWORD, errhp));
(void) OCIAttrSet((void
(void
(ub4)
(ub4)

*) authp, (ub4) OCI_HTYPE_SESSION,
*) "Patch_Bug_12345",
strlen((char *)"Patch_Bug_12345"),
OCI_ATTR_EDITION, errhp);

printf(("Create a new session that connects to the specified edition\n");
if (err = OCISessionGet(envhp, errhp, &svchp, authp,
(OraText *)connstr, (ub4)strlen((char *)connstr), NULL,
0, NULL, NULL, NULL, OCI_DEFAULT))
{
checkerr(errhp, err);
exit(1);
}
checkerr(errhp, OCISessionRelease(svchp, errhp, NULL, (ub4)0, OCI_DEFAULT));
OCIHandleFree((void *)authp, OCI_HTYPE_AUTHINFO);
}

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Chapter 10

OCI Security Enhancements

See Also:
•

OCI_ATTR_EDITION in OCI_ATTR_EDITION

•

Oracle Database Development Guide for a more complete description of
edition-based redefinition

•

Restrictions on Attributes Supported for OCI Session Pool in
OCISessionGet()

•

OCIAttrSet()

10.8 OCI Security Enhancements
The following security enhancements use configured parameters in the init.ora file or
the sqlnet.ora file (the latter file is specifically noted for that feature).
These security enhancements are described in more detail in Oracle Database
Security Guide. These initialization parameters apply to all instances of the database.

See Also:
Oracle Database Security Guide, the section about embedding calls in
middle-tier applications to get, set, and clear client session IDs

This section includes the following topics:
•

Controlling the Database Version Banner Displayed

•

Banners for Unauthorized Access and User Actions Auditing

•

Non-Deferred Linkage

10.8.1 Controlling the Database Version Banner Displayed
The OCIServerVersion() function can be issued before authentication (on a connected
server handle after calling OCIServerAttach()) to get the database version.
To avoid disclosing the database version string before authentication, set the
SEC_RETURN_SERVER_RELEASE_BANNER initialization parameter to NO. For example:
SEC_RETURN_SERVER_RELEASE_BANNER = NO

This displays the following string for Oracle Database Release 11.1 and all
subsequent 11.1 releases and patch sets:
Oracle Database 11g Release 11.1.0.0.0 - Production

Set SEC_RETURN_SERVER_RELEASE_BANNER to YES and then the current banner is displayed.
If you have installed Oracle Database Release 11.2.0.2, the banner displayed is:
Oracle Database 11g Enterprise Edition Release 11.2.0.2 - Production

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OCI Security Enhancements

This feature works with an Oracle Database Release 11.1 or later server, and any
version client.

See Also:
•

OCIServerVersion()

•

OCIServerAttach()

10.8.2 Banners for Unauthorized Access and User Actions Auditing
The following systemwide parameters are in sqlnet.ora and warn users against
unauthorized access and possible auditing of user actions.
These features are available in Oracle Database Release 11.1 and later servers and
clients. The content of the banners is in text files that the database administrator
creates. There is a 512 byte buffer limit for displaying the banner content. If this buffer
limit is exceeded, the banner content will appear to be cut off. The access banner
syntax is:
SEC_USER_UNAUTHORIZED_ACCESS_BANNER = file_path1

In this syntax, file_path1 is the path of a text file. To retrieve the banner, get the value
of the attribute OCI_ATTR_ACCESS_BANNER from the server handle after calls to either
OCIServerAttach() or OCISessionGet().
The audit banner syntax is:
SEC_USER_AUDIT_ACTION_BANNER = file_path2

In this syntax, file_path2 is the path of a text file. To retrieve the banner, get the value
of the attribute OCI_ATTR_AUDIT_BANNER from the session handle after calls to either
OCISessionBegin(), OCISessionGet(), OCILogon(), or OCILogon2().

See Also:
•

OCI_ATTR_ACCESS_BANNER

•

OCI_ATTR_AUDIT_BANNER

•

OCIServerAttach()

•

OCISessionGet()

•

OCISessionBegin()

•

OCILogon()

•

OCILogon2()

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Chapter 10

Overview of OCI Multithreaded Development

10.8.3 Non-Deferred Linkage
Non-deferred linkage of applications is no longer supported and the Makefile is
modified to remove it.
This method of linking was used before OCI V7.

10.9 Overview of OCI Multithreaded Development
Threads are lightweight processes that exist within a larger process.
Threads share the same code and data segments but have their own program
counters, system registers, and stacks. Global and static variables are common to all
threads, and a mutual exclusion mechanism is required to manage access to these
variables from multiple threads within an application.
Once spawned, threads run asynchronously with respect to one another. They can
access common data elements and make OCI calls in any order. Because of this
shared access to data elements, a synchronized mechanism is required to maintain
the integrity of data being accessed.
The mechanism to manage data access takes the form of mutexes (mutual exclusion
locks). This mechanism is implemented to ensure that no conflicts arise between
multiple threads accessing shared internal data that are opaque to users. In OCI,
mutexes are granted for each environment handle.
The thread safety feature of Oracle Database and the OCI libraries allows developers
to use OCI in a multithreaded environment. Thread safety ensures that code can be
reentrant, with multiple threads making OCI calls without side effects.

Note:
Thread safety is not available on every operating system. Check your Oracle
Database system-specific documentation for more information.
In a multithreaded Linux or UNIX environment, OCI calls except OCIBreak()
are not allowed in a user signal handler.
The correct way to use and free handles is to create the handle, use the
handle, then free the handle only after all the threads have been destroyed,
when the application is terminating.

This section includes the following topics:
•

Advantages of OCI Thread Safety

•

OCI Thread Safety and Three-Tier Architectures

•

About Implementing Thread Safety

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See Also:
OCIBreak()

10.9.1 Advantages of OCI Thread Safety
Lists the advantages of implementing thread safety.
The implementation of thread safety in OCI has the following advantages:
•

Multiple threads of execution can make OCI calls with the same result as
successive calls made by a single thread.

•

When multiple threads make OCI calls, there are no side effects between threads.

•

Users who do not write multithreaded programs do not pay a performance penalty
for using thread-safe OCI calls.

•

Use of multiple threads can improve program performance. Gains may be seen on
multiprocessor systems where threads run concurrently on separate processors,
and on single processor systems where overlap can occur between slower
operations and faster operations.

10.9.2 OCI Thread Safety and Three-Tier Architectures
In addition to client/server applications, where the client can be a multithreaded
program, a typical use of multithreaded applications is in three-tier (client-agentserver) architectures.
In this architecture, the client is concerned only with presentation services. The agent
(application server) processes the application logic for the client application. Typically,
this relationship is a many-to-one relationship, with multiple clients sharing the same
application server.
The server tier in this scenario is a database. The application server (agent) is very
well suited to being a multithreaded application server, with each thread serving a
single client application. In an Oracle Database environment, this application server is
an OCI or precompiler program.

10.9.3 About Implementing Thread Safety
To take advantage of thread safety, an application must be running on a thread-safe
operating system.
The application specifies that it is running in a multithreaded environment by making
an OCIEnvNlsCreate() call with OCI_THREADED as the value of the mode parameter.
All subsequent calls to OCIEnvNlsCreate() must also be made with OCI_THREADED.

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Note:
Applications running on non-thread-safe operating systems must not pass a
value of OCI_THREADED to OCIEnvCreate() or OCIEnvNlsCreate().

If an application is single-threaded, whether or not the operating system is thread-safe,
the application must pass a value of OCI_DEFAULT to OCIEnvCreate() or
OCIEnvNlsCreate(). Single-threaded applications that run in OCI_THREADED mode may
incur lower performance.
If a multithreaded application is running on a thread-safe operating system, the OCI
library manages mutexes for the application for each environment handle. An
application can override this feature and maintain its own mutex scheme by specifying
a value of OCI_ENV_NO_MUTEX in the mode parameter of either the OCIEnvCreate() or
OCIEnvNlsCreate() calls.
The following scenarios are possible, depending on how many connections exist in
each environment handle, and how many threads are spawned in each connection.
•

If an application has multiple environment handles, with a single thread in each,
mutexes are not required.

•

If an application running in OCI_THREADED mode maintains one or more environment
handles, with multiple connections, it has these options:
–

Pass a value of OCI_ENV_NO_MUTEX for the mode of OCIEnvNlsCreate(). The
application must set mutual exclusion locks (mutex) for OCI calls made on the
same environment handle. This has the advantage that the mutex scheme can
be optimized to the application design. The programmer must also ensure that
only one OCI call is in process on the environment handle connection at any
given time.

–

Pass a value of OCI_DEFAULT for the mode of OCIEnvNlsCreate(). The OCI library
automatically gets a mutex on every OCI call on the same environment
handle.

Note:
Most processing of an OCI call happens on the server, so if two
threads using OCI calls go to the same connection, then one of them
can be blocked while the other finishes processing at the server.
Use one error handle for each thread in an application, because OCI
errors can be overwritten by other threads.
This section includes the following topics:
•

About Polling Mode Operations and Thread Safety

•

Mixing 7.x and Later Release OCI Calls

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See Also:
•

OCIEnvNlsCreate()

•

OCIEnvCreate()

10.9.3.1 About Polling Mode Operations and Thread Safety
OCI supports polling mode operations.
When OCI is operating in threaded mode, OCI calls that poll for completion acquire
mutexes when the OCI call is actively executing. However, when OCI returns control
to the application, OCI releases any acquired mutexes. The caller should ensure that
no other OCI call is made on the connection until the polling mode OCI operation in
progress completes.

See Also:
Polling Mode Operations in OCI

10.9.3.2 Mixing 7.x and Later Release OCI Calls
If an application is mixing later release and 7.x OCI calls, and the application has been
initialized as thread-safe (with the appropriate calls of the later release), it is not
necessary to call opinit() to achieve thread safety.
The application gets 7.x behavior on any subsequent 7.x function calls.

10.10 OCIThread Package
The OCIThread package provides some commonly used threading primitives.
The OCIThread package offers a portable interface to threading capabilities native to
various operating systems, but does not implement threading on operating systems
that do not have native threading capability.
OCIThread does not provide a portable implementation, but it serves as a set of portable

covers for native multithreaded facilities. Therefore, operating systems that do not
have native support for multithreading are only able to support a limited
implementation of the OCIThread package. As a result, products that rely on all of the
OCIThread functionality do not port to all operating systems. Products that must be
ported to all operating systems must use only a subset of the OCIThread functionality.
The OCIThread API consists of three main parts. Each part is described briefly here.
The following subsections describe each in greater detail:
•

Initialization and Termination. These calls deal with the initialization and
termination of OCIThread context, which is required for other OCIThread calls.
OCIThread only requires that the process initialization function,
OCIThreadProcessInit(), is called when OCIThread is being used in a multithreaded

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application. Failing to call OCIThreadProcessInit() in a single-threaded application
is not an error.
Separate calls to OCIThreadInit() all return the same OCIThread context. Each call
to OCIThreadInit() must eventually be matched by a call to OCIThreadTerm().
•

Passive Threading Primitives. Passive threading primitives are used to manipulate
mutual exclusion locks (mutex), thread IDs, and thread-specific data keys. These
primitives are described as passive because although their specifications allow for
the existence of multiple threads, they do not require it. It is possible for these
primitives to be implemented according to specification in both single-threaded
and multithreaded environments. As a result, OCIThread clients that use only these
primitives do not require a multiple-thread environment to work correctly. They are
able to work in single-threaded environments without branching code.

•

Active Threading Primitives. Active threading primitives deal with the creation,
termination, and manipulation of threads. These primitives are described as active
because they can only be used in true multithreaded environments. Their
specification explicitly requires multiple threads. If you must determine at run time
whether you are in a multithreaded environment, call OCIThreadIsMulti() before
using an OCIThread active threading primitive.
To write a version of the same application to run on single-threaded operating
system, it is necessary to branch your code, whether by branching versions of the
source file or by branching at run time with the OCIThreadIsMuilt() call.

See Also:
•
•

Thread Management Functions
cdemothr.c in the demo directory is an example of a multithreading

application
•

OCIThreadProcessInit()

•

OCIThreadInit()

•

OCIThreadTerm()

•

OCIThreadIsMulti()

10.10.1 Initialization and Termination
The types and functions described in this section are associated with the initialization
and termination of the OCIThread package. OCIThread must be initialized before you can
use any of its functionality.
The observed behavior of the initialization and termination functions is the same
regardless of whether OCIThread is in a single-threaded or a multithreaded
environment. Table 10-6 lists functions for thread initialization and termination.
Table 10-6

Initialization and Termination Multithreading Functions

Function

Purpose

OCIThreadProcessInit()

Performs OCIThread process initialization

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Table 10-6

(Cont.) Initialization and Termination Multithreading Functions

Function

Purpose

OCIThreadInit()

Initializes OCIThread context

OCIThreadTerm()

Terminates the OCIThread layer and frees context
memory

OCIThreadIsMulti()

Tells the caller whether the application is running in a
multithreaded environment or a single-threaded
environment

This section includes the following topic: OCIThread Context.

See Also:
Thread Management Functions

10.10.1.1 OCIThread Context
Most calls to OCIThread functions use the OCI environment or user session handle as a
parameter.
The OCIThread context is part of the OCI environment or user session handle, and it
must be initialized by calling OCIThreadInit(). Termination of the OCIThread context
occurs by calling OCIThreadTerm().

Note:
The OCIThread context is an opaque data structure. Do not attempt to
examine the contents of the context.

See Also:
•

OCIThreadInit()

•

OCIThreadTerm()

10.10.2 Passive Threading Primitives
Lists the passive threading primitive functions.
The passive threading primitives deal with the manipulation of mutex, thread IDs, and
thread-specific data. Because the specifications of these primitives do not require the
existence of multiple threads, they can be used both in multithreaded and singlethreaded operating systems. Table 10-7 lists functions used to implement passive
threading.

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Table 10-7

Passive Threading Primitives

Function

Purpose

OCIThreadMutexInit()

Allocates and initializes a mutex

OCIThreadMutexDestroy()

Destroys and deallocates a mutex

OCIThreadMutexAcquire()

Acquires a mutex for the thread in which it is called

OCIThreadMutexRelease()

Releases a mutex

OCIThreadKeyInit()

Allocates and generates a new key

OCIThreadKeyDestroy()

Destroys and deallocates a key

OCIThreadKeyGet()

Gets the calling thread's current value for a key

OCIThreadKeySet()

Sets the calling thread's value for a key

OCIThreadIdInit()

Allocates and initializes a thread ID

OCIThreadIdDestroy()

Destroys and deallocates a thread ID

OCIThreadIdSet()

Sets one thread ID to another

OCIThreadIdSetNull()

Nulls a thread ID

OCIThreadIdGet()

Retrieves a thread ID for the thread in which it is called

OCIThreadIdSame()

Determines if two thread IDs represent the same thread

OCIThreadIdNull()

Determines if a thread ID is NULL

This section includes the following topics:
•

OCIThreadMutex

•

OCIThreadKey

•

OCIThreadKeyDestFunc

•

OCIThreadId

10.10.2.1 OCIThreadMutex
The OCIThreadMutex data type is used to represent a mutex.
This mutex is used to ensure that either:
•

Only one thread accesses a given set of data at a time

•

Only one thread executes a given critical section of code at a time

Mutex pointers can be declared as parts of client structures or as standalone
variables. Before they can be used, they must be initialized using
OCIThreadMutexInit(). Once they are no longer needed, they must be destroyed using
OCIThreadMutexDestroy().
A thread can acquire a mutex by using OCIThreadMutexAcquire(). This ensures that only
one thread at a time is allowed to hold a given mutex. A thread that holds a mutex can
release it by calling OCIThreadMutexRelease().

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See Also:
•

OCIThreadMutexInit()

•

OCIThreadMutexDestroy()

•

OCIThreadMutexAcquire()

•

OCIThreadMutexRelease()

10.10.2.2 OCIThreadKey
The data type OCIThreadKey can be thought of as a process-wide variable with a
thread-specific value.
Thus all threads in a process can use a given key, but each thread can examine or
modify that key independently of the other threads. The value that a thread sees when
it examines the key is always the same as the value that it last set for the key. It does
not see any values set for the key by other threads. The data type of the value held by
a key is a void * generic pointer.
Keys can be created using OCIThreadKeyInit(). Key value are initialized to NULL for all
threads.
A thread can set a key's value using OCIThreadKeySet(). A thread can get a key's value
using OCIThreadKeyGet().
The OCIThread key functions save and retrieve data specific to the thread. When clients
maintain a pool of threads and assign them to different tasks, it may not be appropriate
for a task to use OCIThread key functions to save data associated with it.
Here is a scenario of how things can fail: A thread is assigned to execute the
initialization of a task. During initialization, the task stores data in the thread using
OCIThread key functions. After initialization, the thread is returned to the threads pool.
Later, the threads pool manager assigns another thread to perform some operations
on the task, and the task must retrieve the data it stored earlier in initialization.
Because the task is running in another thread, it is not able to retrieve the same data.
Application developers that use thread pools must be aware of this.

See Also:
•

OCIThreadKeyInit()

•

OCIThreadKeySet()

•

OCIThreadKeyGet()

10.10.2.3 OCIThreadKeyDestFunc
OCIThreadKeyDestFunc is the type of a pointer to a key's destructor routine.

Keys can be associated with a destructor routine when they are created using
OCIThreadKeyInit(). A key's destructor routine is called whenever a thread with a non-

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NULL value for the key terminates. The destructor routine returns nothing and takes one

parameter, the value that was set for key when the thread terminated.
The destructor routine is guaranteed to be called on a thread's value in the key after
the termination of the thread and before process termination. No more precise
guarantee can be made about the timing of the destructor routine call; no code in the
process may assume any post-condition of the destructor routine. In particular, the
destructor is not guaranteed to execute before a join call on the terminated thread
returns.

See Also:
OCIThreadKeyInit()

10.10.2.4 OCIThreadId
OCIThreadId data type is used to identify a thread.

At any given time, no two threads can have the same OCIThreadId, but OCIThreadId
values can be recycled; after a thread dies, a new thread may be created that has the
same OCIThreadId value. In particular, the thread ID must uniquely identify a thread T
within a process, and it must be consistent and valid in all threads U of the process for
which it can be guaranteed that T is running concurrently with U. The thread ID for a
thread T must be retrievable within thread T. This is done using OCIThreadIdGet().
The OCIThreadId type supports the concept of a NULL thread ID: the NULL thread ID can
never be the same as the ID of an actual thread.

See Also:
OCIThreadIdGet()

10.10.3 Active Threading Primitives
Lists the active threading primitives, which deal with manipulation of actual threads.
Because specifications of most of these primitives require multiple threads, they work
correctly only in the enabled OCIThread. In the disabled OCIThread, they always return
an error. The exception is OCIThreadHandleGet(); it may be called in a single-threaded
environment and has no effect.
Active primitives can only be called by code running in a multithreaded environment.
You can call OCIThreadIsMulti() to determine whether the environment is
multithreaded or single-threaded. Table 10-8 lists functions used to implement active
threading.

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Table 10-8

Active Threading Primitives

Function

Purpose

OCIThreadHndInit()

Allocates and initializes a thread handle

OCIThreadHndDestroy()

Destroys and deallocates a thread handle

OCIThreadCreate()

Creates a new thread

OCIThreadJoin()

Allows the calling thread to join with another

OCIThreadClose()

Closes a thread handle

OCIThreadHandleGet()

Retrieves a thread handle

This section includes the following topic: OCIThreadHandle.

See Also:
OCIThreadIsMulti()

10.10.3.1 OCIThreadHandle
Data type OCIThreadHandle is used to manipulate a thread in the active primitives,
OCIThreadJoin() and OCIThreadClose().
A thread handle opened by OCIThreadCreate() must be closed in a matching call to
OCIThreadClose(). A thread handle is invalid after the call to OCIThreadClose().

See Also:
•

OCIThreadJoin()

•

OCIThreadClose()

•

OCIThreadCreate()

10-43

11
Session Pooling and Connection Pooling in
OCI
This chapter describes OCI session pooling and connection pooling features.
This chapter contains these topics:
•

Session Pooling in OCI

•

Database Resident Connection Pooling

•

About Using Oracle Connection Manager in Traffic Director Mode

•

Connection Pooling in OCI

•

When to Use Connection Pooling, Session Pooling, or Neither

11.1 Session Pooling in OCI
Session pooling means that the application creates and maintains a group of stateless
sessions to the database.
These sessions are provided to thin clients as requested. If no sessions are available,
a new one may be created. When the client is done with the session, the client
releases it to the pool. Thus, the number of sessions in the pool can increase
dynamically.
Some of the sessions in the pool may be tagged with certain properties. For instance,
a user may request a default session, set certain attributes on it, label it or tag it, and
return it to the pool. That user, or some other user, can require a session with the
same attributes, and thus request a session with the same tag. There may be several
sessions in the pool with the same tag. The tag on a session can be changed or reset.
Proxy sessions, too, can be created and maintained through session pooling in OCI.
The behavior of the application when no free sessions are available and the pool has
reached its maximum size depends on certain attributes. A new session may be
created or an error returned, or the thread may just block and wait for a session to
become free.
The main benefit of session pooling is performance. Making a connection to the
database is a time-consuming activity, especially when the database is remote. Thus,
instead of a client spending time connecting to the server, authenticating its
credentials, and then receiving a valid session, it can just pick one from the pool.
This section includes the following topics:
•

Functionality of OCI Session Pooling

•

Homogeneous and Heterogeneous Session Pools

•

About Using Tags in Session Pools

•

OCI Handles for Session Pooling

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•

Using OCI Session Pooling

•

OCI Calls for Session Pooling

•

Example of OCI Session Pooling

See Also:
About Using Tags in Session Pools

11.1.1 Functionality of OCI Session Pooling
Describes tasks that session pooling can perform.
Session pooling can perform the following tasks:
•

Create, maintain, and manage a pool of stateless sessions transparently.

•

Provide an interface for the application to create a pool and specify the minimum,
increment, and maximum number of sessions in the pool.

•

Provide an interface for the user to obtain and release a default or tagged session
to the pool. A tagged session is one with certain client-defined properties.

•

Allow the application to dynamically change the number of minimum and
maximum number of sessions.

•

Provide a mechanism to always maintain an optimum number of open sessions,
by closing sessions that have been idle for a very long time, and creating sessions
when required.

•

Allow for session pooling with authentication.

11.1.2 Homogeneous and Heterogeneous Session Pools
A session pool can be either homogeneous or heterogeneous.
Homogeneous session pooling means that sessions in the pool are alike for
authentication (they have the same user name, password, and privileges).
Heterogeneous session pooling means that you must provide authentication
information because the sessions can have different security attributes and privileges.

11.1.3 About Using Tags in Session Pools
Tags provide a way for users to customize sessions in the pool.
A client can get a default or untagged session from a pool, set certain attributes on the
session (such as NLS settings), and return the session to the pool, labeling it with an
appropriate tag in the OCISessionRelease() call.
The original user, or some other user, can request a session with the same tags to
have a session with the same attributes, and can do so by providing the same tag in
the OCISessionGet() call.
This section includes the following topic: Multi-Property Tags.

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See Also:
•

OCISessionRelease()

•

OCISessionGet()

11.1.3.1 Multi-Property Tags
Beginning with 12c Release 2 (12.2), a tag can have multiple properties. This is
referred to as a multi-property tag.
A multi-property tag is comprised of one or more =
pairs separated by a semi-colon, where = are both
strings.
During an OCISessionGet() call, in the taginfo parameter, the property name appearing
first is given the highest property for finding a match and the property name appearing
last is given the lowest priority. Therefore the ordering of the properties in the string is
significant in determining a matching session in the pool. The example that follows
below the list of restrictions illustrates this point.
This functionality also works with DRCP.
The following restrictions apply to property names and property values that can be
passed in a multi-property tag:
•

Both the property name and the property value are case sensitive.

•

A property name can occur only once in a tag. In case the same property name is
specified more than once, an error will be thrown.

•

A non empty string should be specified for both the property name and the value.

•

Leading and trailing spaces before and after a property name and leading and
trailing space before and after a property value will be truncated. For example,
“PDB = PDB1” is treated as “PDB=PDB1”.

•

There should be no white spaces in the property name and the property value. For
example, NLS  LANGUAGE=French will result in an error because of the
space between NLS and LANGUAGE.

To explain the notion of multiple properties, assume that the application to be
deployed in a CDB environment requires that the session get requests should be
satisfied with sessions from the same pluggable database (for example, pdb1 ) as
much as possible. Next, it also requires that the sessions belong to the same language
(for example, FRENCH), but gives a higher priority to sessions to pdb1. The
application can then provide a multi-property-tag as follows:
char *props = “PDB=pdb1;LANGUAGE=FRENCH”

Now, assume that there are two sessions in the pool with properties as shown:
Session 1 = > “PDB=pdb1;LANGUAGE=CHINESE”
Session 2 = > “PDB=pdb2;LANGUAGE=FRENCH”

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In this situation, the session get request (OCISessionGet()) returns Session 1 because
the PDB property implicitly carries a higher priority by being placed ahead of the
LANGUAGE property.

See Also:
OCISessionGet() for a further discussion of tagging sessions

This section includes the following topic: PL/SQL Callback for Session State Fix Up.

11.1.3.1.1 PL/SQL Callback for Session State Fix Up
When using multi-property tags, a PL/SQL based fix-up callback for the session state
can be provided on the server.
This application-provided callback transforms a session checked out from the pool to
the desired state requested by the application as indicated by the multi-property tag.
This callback works with or without Database Resident Connection Pooling (DRCP).
Using this callback can improve the performance of your application because the fixup logic is run for the session state on the server. So, this feature eliminates
application round-trips to the database for the fix-up logic. The callback is supplied by
the user who connects using OCISessionGet(). The callback must be provided as an
attribute OCI_ATTR_FIXUP_CALLBACK on the authentication handle passed to
OCISessionGet() for applications not using OCISessionPool or using custom pools. For
applications using OCISessionPool this attribute must be set on the authentication
handle, which in turn must be set on the session pool handle as the attribute
OCI_ATTR_SPOOL_AUTH.
Example 11-1

Example of PL/SQL Fix-Up Callback

Following is an example implementation of the PL/SQL fix-up callback to fix up the
session properties SCHEMA and CURRENCY:
CREATE OR REPLACE PACKAGE mycb_pack AS
TYPE prop_t IS TABLE OF varchar2(64) index by varchar2(64);
PROCEDURE mycallback (
desired_props IN VARCHAR2,
actual_props IN VARCHAR2
);
PROCEDURE buildTab(propTab in out prop_t, props in varchar2);
END;
/
CREATE OR REPLACE PACKAGE BODY mycb_pack AS
procedure buildTab(propTab in out prop_t, props in varchar2 ) is
property VARCHAR2(64);
key VARCHAR2(64);
value VARCHAR2(64);
pos number;
pos2 number;
pos3 number;
idx1 number;
begin
idx1:=1;

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pos:=1;
pos2:=1;
pos3:=1;
property := 'tmp';
while (pos > 0 and length(props)>pos)
loop
pos := instr (props, ';', 1, idx1);
if (pos=0)
then
property := substr (props, pos2);
else
property := substr (props, pos2, pos-pos2);
end if
pos2 := pos+1;
pos3 := instr (property, '=', 1, 1);
key := substr (property, 1, pos3-1);
value := substr (property, pos3+1);
propTab(key) := value;
idx1 := idx1+1;
end loop;
end;
PROCEDURE mycallback (
desired_props IN VARCHAR2,
actual_props IN VARCHAR2
) IS
actPropTab prop_t;
desPropTab prop_t;
idx varchar2(64);
begin
-- iterate through the desired props to set the session state appropriately
idx := desPropTab.first;
while (idx is not null)
loop
if (idx = 'CURRENCY') then
EXECUTE IMMEDIATE 'ALTER SESSION SET NLS_CURRENCY=''' || desPropTab(idx) ||
'''';
elsif (idx = 'SCHEMA') then
EXECUTE IMMEDIATE 'ALTER SESSION SET CURRENT_SCHEMA=''' || desPropTab(idx)
|| '''';
end if;
idx := desPropTab.next(idx);
end loop;
-- may iterate over the actual props to set any extra props to a default state
end;
end mycb_pack;
/

See Also:
•

Authentication Information Handle Attributes for more information about
OCI_ATTR_FIXUP_CALLBACK

•

Session Pool Handle Attributes for more information about
OCI_ATTR_SPOOL_AUTH

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11.1.4 OCI Handles for Session Pooling
What are the handle types for session pooling.
The following handle types are for session pooling:
•

OCISPool

•

OCIAuthInfo

11.1.4.1 OCISPool
This is the session pool handle.
It is allocated using OCIHandleAlloc(). It must be passed to OCISessionPoolCreate() and
OCISessionPoolDestroy(). It has the attribute type OCI_HTYPE_SPOOL.
An example of the OCIHandleAlloc() call follows:
OCISPool *spoolhp;
OCIHandleAlloc((void *) envhp, (void **) &spoolhp, OCI_HTYPE_SPOOL,
(size_t) 0, (void **) 0));

For an environment handle, multiple session pools can be created.

See Also:
•

OCIHandleAlloc()

•

OCISessionPoolCreate()

•

OCISessionPoolDestroy()

11.1.4.2 OCIAuthInfo
This is the authentication information handle.
It is allocated using OCIHandleAlloc(). It is passed to OCISessionGet(). It supports all the
attributes that are supported for a user session handle. The authentication information
handle has the attribute type OCI_HTYPE_AUTHINFO (see Table 4-1).
An example of the OCIHandleAlloc() call follows:
OCIAuthInfo *authp;
OCIHandleAlloc((void *) envhp, (void **) &authp, OCI_HTYPE_AUTHINFO,
(size_t) 0, (void **) 0));

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See Also:
•

OCIHandleAlloc()

•

User Session Handle Attributes for the attributes that belong to the
authentication information handle

•

Session Pool Handle Attributes for more information about the session
pooling attributes

•

Connect, Authorize, and Initialize Functions for complete information
about the functions used in session pooling

•

See "OCISessionGet()" for details of the session handle attributes that
you can use with this call

11.1.5 Using OCI Session Pooling
Shows the steps to write a simple session pooling application that uses a user name
and password.
The steps in writing a simple session pooling application that uses a user name and
password are as follows:
1.

Allocate the session pool handle using OCIHandleAlloc() for an OCISPool handle.
Multiple session pools can be created for an environment handle.

2.

Create the session pool using OCISessionPoolCreate() with mode set to OCI_DEFAULT
(for a new session pool). See the function for a discussion of the other modes.

3.

Loop for each thread. Create the thread with a function that does the following:
a.

Allocates an authentication information handle of type OCIAuthInfo using
OCIHandleAlloc()

b.

Sets the user name and password in the authentication information handle
using OCIAttrSet()

c.

Gets a pooled session using OCISessionGet() with mode set to
OCI_SESSGET_SPOOL

d.

Performs the transaction

e.

Allocates the handle

f.

Prepares the statement

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Chapter 11

Session Pooling in OCI

Note:
When using service contexts obtained from OCI session pool, you
are required to use the service context returned by OCISessionGet()
(or OCILogon2()), and not create other service contexts outside of
these calls.
Any statement handle obtained using OCIStmtPrepare2() with the
service context should be subsequently used only in conjunction with
the same service context, and never with a different service context.

4.

g.

Executes the statement

h.

Commits or rolls back the transactions

i.

Releases the session (log off) with OCISessionRelease()

j.

Frees the authentication information handle with OCIHandleFree()

k.

Ends the loop for each thread

Destroy the session pool using OCISessionPoolDestroy().

See Also:
•

OCISessionPoolCreate()

•

OCIHandleAlloc()

•

OCIAttrSet()

•

OCISessionGet()

•

OCILogon2()

•

OCIStmtPrepare2()

•

OCISessionRelease()

•

OCIHandleFree()

•

OCISessionPoolDestroy()

11.1.6 OCI Calls for Session Pooling
Describes the usages for OCI calls for session pooling.
OCI provides calls for session pooling to perform the following tasks:
•

Allocate the Pool Handle

•

Create the Connection Pool

•

Log On to the Database

•

Log Off from the Database

•

Destroy the Connection Pool

•

Free the Pool Handle

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Chapter 11

Session Pooling in OCI

11.1.6.1 Allocate the Pool Handle
Session pooling requires that the pool handle OCI_HTYPE_SPOOL be allocated by calling
OCIHandleAlloc().
Multiple pools can be created for a given environment handle. For a single session
pool, here is an allocation example:
OCISPool *poolhp;
OCIHandleAlloc((void *) envhp, (void **) &poolhp, OCI_HTYPE_SPOOL, (size_t) 0,
(void **) 0));

See Also:
OCIHandleAlloc()

11.1.6.2 Create the Pool Session
You can use the function OCISessionPoolCreate() to create the session pool.
Here is an example of how to use this call:
OCISessionPoolCreate(envhp, errhp, poolhp, (OraText **)&poolName,
(ub4 *)&poolNameLen, database,
(ub4)strlen((const signed char *)database),
sessMin, sessMax, sessIncr,
(OraText *)appusername,
(ub4)strlen((const signed char *)appusername),
(OraText *)apppassword,
(ub4)strlen((const signed char *)apppassword),
OCI_DEFAULT);

See Also:
OCISessionPoolCreate()

11.1.6.3 Log On to the Database
You can use these calls to log on to the database in session pooling mode.
•

OCILogon2()

This is the simplest call. However, it does not give the user the option of using
tagging. Here is an example of how to use OCILogon2() to log on to the database in
session pooling mode:
for (i = 0; i < MAXTHREADS; ++i)
{
OCILogon2(envhp, errhp, &svchp[i], "hr", 2, "hr", 2, poolName,
poolNameLen, OCI_LOGON2_SPOOL));
}

•

OCISessionGet()

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Session Pooling in OCI

This is the recommended call to use. It gives the user the option of using tagging
to label sessions in the pool, which makes it easier to retrieve specific sessions.
An example of using OCISessionGet() follows. It is taken from cdemosp.c in the demo
directory.
OCISessionGet(envhp, errhp, &svchp, authInfop,
(OraText *)database,strlen(database), tag,
strlen(tag), &retTag, &retTagLen, &found,
OCI_SESSGET_SPOOL);

When using service contexts obtained from an OCI session pool, you are required
to use the service context returned by OCISessionGet() (or OCILogon2()), and not
create other service contexts outside of these calls.
Any statement handle obtained using OCIStmtPrepare2() with the service context
should be subsequently used only in conjunction with the same service context,
and never with a different service context.

See Also:
•

OCILogon2()

•

OCISessionGet()

•

OCIStmtPrepare2()

11.1.6.4 Log Off from the Database
Indicates two ways in which to log off from the database in session pooling mode
depending on the logon call.
From the following calls, choose the one that corresponds to the logon call and use it
to log off from the database in session pooling mode.
•

OCILogoff()

If you used OCILogon2() to make the connection, you must call OCILogoff() to log
off.
•

OCISessionRelease()

If you used OCISessionGet() to make the connection, then you must call
OCISessionRelease() to log off. Pending transactions are automatically committed.

See Also:
•

OCILogoff()

•

OCILogon2()

•

OCISessionRelease()

•

OCISessionGet()

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Chapter 11

Database Resident Connection Pooling

11.1.6.5 Destroy the Session Pool
Call OCISessionPoolDestroy() to destroy the session pool.
This is shown in the following example:
OCISessionPoolDestroy(poolhp, errhp, OCI_DEFAULT);

See Also:
OCISessionPoolDestroy()

11.1.6.6 Free the Pool Handle
Call OCIHandleFree() to free the session pool handle.
This is shown in the following example:
OCIHandleFree((void *)poolhp, OCI_HTYPE_SPOOL);

Note:
Developers: You are advised to commit or roll back any open transaction
before releasing the connection back to the pool. If this is not done, Oracle
Database automatically commits any open transaction when the connection
is released.
If an instance failure is detected while the session pool is being used, OCI
tries to clean up the sessions to that instance.

See Also:
OCIHandleFree()

11.1.7 Example of OCI Session Pooling
Where to find an example of session pooling in a tested complete program.
For an example of session pooling in a tested complete program, see cdemosp.c in
directory demo.

11.2 Database Resident Connection Pooling
Database resident connection pooling (DRCP) provides a connection pool in the
database server for typical web application usage scenarios where the application
acquires a database connection, works on it for a relatively short duration, and then
releases it.

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Chapter 11

About Using Oracle Connection Manager in Traffic Director Mode

DRCP pools server processes, each of which is the equivalent of a dedicated server
process and a database session combined. (Henceforth these "dedicated" server
processes are referred to as pooled servers.)
DRCP complements middle-tier connection pools that share connections between
threads in a middle-tier process. In addition, DRCP enables sharing of database
connections across middle-tier processes on the same middle-tier host and even
across middle-tier hosts. This results in significant reduction in key database resources
needed to support a large number of client connections, thereby reducing the
database tier memory footprint and boosting the scalability of both middle-tier and
database tiers. Having a pool of readily available servers has the additional benefit of
reducing the cost of creating and tearing down client connections.
DRCP is especially relevant for architectures with multiprocess single-threaded
application servers (such as PHP/Apache) that cannot do middle-tier connection
pooling. Using DRCP, the database can scale to tens of thousands of simultaneous
connections.

See Also:
Oracle Database Development Guide for complete information about DRCP

11.3 About Using Oracle Connection Manager in Traffic
Director Mode
Oracle Connection Manager in Traffic Director Mode is a proxy that is placed between
supported database clients and database instances.
Supported clients from Oracle Database 11g Release 2 (11.2) and later can connect to
Oracle Connection Manager in Traffic Director Mode. Oracle Connection Manager in
Traffic Director Mode provides improved high availability (HA) for planned and
unplanned database server outages, connection multiplexing support, and load
balancing. Support for Oracle Connection Manager in Traffic Director Mode is
described in more detail in the following sections
•

Modes of Operation

•

Key Features

Modes of Operation
Oracle Connection Manager in Traffic Director Mode supports the following modes of
operation:
•

In pooled connection mode, Oracle Connection Manager in Traffic Director Mode
supports any application using the following database client releases:
–

OCI, OCCI, and Open Source Drivers (Oracle Database 11g release 2
(11.2.0.4) and later))

–

JDBC (Oracle Database 12c release 1 (12.1) and later)

–

ODP.NET (Oracle Database 12c release 2 (12.2) and later)

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Chapter 11

About Using Oracle Connection Manager in Traffic Director Mode

In addition, applications must use DRCP. That is, the application must enable
DRCP in the connect string (or in the tnsnames.ora alias).
•

In non-pooled connection (or dedicated) mode, Oracle Connection Manager in
Traffic Director Mode supports any application using database client releases
Oracle Database 11g release 2 (11.2.0.4) and later. In this mode, some
capabilities, such as connection multiplexing are not available.

Key Features
Oracle Connection Manager in Traffic Director Mode furnishes support for the
following:
•

•

Transparent performance enhancements and connection multiplexing, which
includes:
–

Statement caching, rows prefetching, and result set caching are auto-enabled
for all modes of operation.

–

Database session multiplexing (pooled mode only) using the proxy resident
connection pool (PRCP), where PRCP is a proxy mode of Database Resident
Connection Pooling (DRCP). Applications get transparent connect-time load
balancing and run-time load balancing between Oracle Connection Manager in
Traffic Director Mode and the database.

–

For multiple Oracle Connection Manager in Traffic Director Mode instances,
applications get increased scalability through client-side connect time load
balancing or with a load balancer (BIG-IP, NGINX, and others)

Zero application downtime
–

Planned database maintenance or pluggable database (PDB) relocation
*

Pooled mode
Oracle Connection Manager in Traffic Director Mode responds to Oracle
Notification Service (ONS) events for planned outages and redirects work.
Connections are drained from the pool on Oracle Connection Manager in
Traffic Director Mode when the request completes. Service relocation is
supported for Oracle Database 11g release 2 (11.2.0.4) and later.
For PDB relocation, Oracle Connection Manager in Traffic Director Mode
responds to in-band notifications when a PDB is relocated, that is even
when ONS is not configured (for Oracle Database release 18c, version
18.1 and later server only)

*

Non-pooled or dedicated mode
When there is no request boundary information from the client, Oracle
Connection Manager in Traffic Director Mode supports planned outage for
many applications (as long as only simple session state and cursor state
need to be preserved across the request/transaction boundaries). This
support includes:

–

*

Stop service/PDB at the transaction boundary or it leverages Oracle
Database release 18c continuous application availability to stop the
service at the request boundary

*

Oracle Connection Manager in Traffic Director Mode leverages
Transparent Application Failover (TAF) failover restore to reconnect
and restore simple states.

Unplanned database outages for read-mostly workloads

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Chapter 11

About Using Oracle Connection Manager in Traffic Director Mode

•

•

High Availability of Oracle Connection Manager in Traffic Director Mode to avoid a
single point of failure. This is supported by:
–

Multiple instances of Oracle Connection Manager in Traffic Director Mode
using a load balancer or client side load balancing/failover in the connect
string

–

Rolling upgrade of Oracle Connection Manager in Traffic Director Mode
instances

–

Graceful close of existing connections from client to Oracle Connection
Manager in Traffic Director Mode for planned outages

–

In-band notifications to Oracle Database release 18c and later clients

–

For older clients, notifications are sent with the response of the current request

For security and isolation, Oracle Connection Manager in Traffic Director Mode
furnishes:
–

Database Proxy supporting transmission control protocol/transmission control
protocol secure (TCP/TCPS) and protocol conversion

–

Firewall based on the IP address, service name, and secure socket layer/
transport layer security (SSL/TLS) wallets

–

Tenant isolation in a multi-tenant environment

–

Protection against denial-of-service and fuzzing attacks

–

Secure tunneling of database traffic across Oracle Database on-premises and
Oracle Cloud

See Also:
•

Oracle Database Net Services Administrator's Guide for information
about configuring cman.ora configuration file to set up Oracle Connection
Manager in Traffic Director Mode

•

Oracle Database Net Services Administrator's Guide for information
about configuring databases for Oracle Connection Manager in Traffic
Director Mode proxy authentication

•

Oracle Database Net Services Administrator's Guide for information
about configuring Oracle Connection Manager in Traffic Director Mode
for unplanned down events

•

Oracle Database Net Services Administrator's Guide for information
about configuring Oracle Connection Manager in Traffic Director Mode
for planned down events

•

Oracle Database Net Services Administrator's Guide for information
about configuring proxy resident connection pools for use by Oracle
Connection Manager in Traffic Director Mode

•

Oracle Database Net Services Administrator's Guide for information
about functionality not supported for all drivers with Oracle Connection
Manager in Traffic Director Mode

•

Oracle Database Net Services Reference for an overview of Oracle
CMAN configuration file

11-14

Chapter 11

Connection Pooling in OCI

11.4 Connection Pooling in OCI
Connection pooling is the use of a group (the pool) of reusable physical connections
by several sessions to balance loads.
The pool is managed by OCI, not the application. Applications that can use connection
pooling include middle-tier applications for web application servers and email servers.
One use of this feature is in a web application server connected to a back-end Oracle
database. Suppose that a web application server gets several concurrent requests for
data from the database server. The application can create a pool (or a set of pools) in
each environment during application initialization.
This section includes the following topics:
•

OCI Connection Pooling Concepts

•

Using OCI Calls for Connection Pooling

•

Examples of OCI Connection Pooling

11.4.1 OCI Connection Pooling Concepts
Oracle Database has several transaction monitoring capabilities such as the finegrained management of database sessions and connections. Fine-grained
management of database sessions is done by separating the notion of database
sessions (user handles) from connections (server handles). By using OCI calls for
session switching and session migration, an application server or transaction monitor
can multiplex several sessions over fewer physical connections, thus achieving a high
degree of scalability by pooling connections and back-end Oracle server processes.
The connection pool itself is normally configured with a shared pool of physical
connections, translating to a back-end server pool containing an identical number of
dedicated server processes.
The number of physical connections is less than the number of database sessions in
use by the application. The number of physical connections and back-end server
processes are also reduced by using connection pooling. Thus many more database
sessions can be multiplexed.
This section includes the following topics:
•

Similarities and Differences from a Shared Server

•

Stateless Sessions Versus Stateful Sessions

•

Multiple Connection Pools

•

Transparent Application Failover

11.4.1.1 Similarities and Differences from a Shared Server
Connection pooling on the middletier is similar to what a shared server offers on the
back end.
Connection pooling makes a dedicated server instance behave like a shared server
instance by managing the session multiplexing logic on the middle tier.

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Connection Pooling in OCI

The connection pool on the middle tier controls the pooling of dedicated server
processes including incoming connections into the dedicated server processes. The
main difference between connection pooling and a shared server is that in the latter
case, the connection from the client is normally to a dispatcher in the database
instance. The dispatcher is responsible for directing the client request to an
appropriate shared server. However, the physical connection from the connection pool
is established directly from the middletier to the dedicated server process in the backend server pool.
Connection pooling is beneficial only if the middle tier is multithreaded. Each thread
can maintain a session to the database. The actual connections to the database are
maintained by the connection pool, and these connections (including the pool of
dedicated database server processes) are shared among all the threads in the middle
tier.

11.4.1.2 Stateless Sessions Versus Stateful Sessions
Stateless sessions are serially reusable across mid-tier threads.
After a thread is done processing a database request on behalf of a three-tier user, the
same database session can be reused for a completely different request on behalf of a
completely different three-tier user.
Stateful sessions to the database, however, are not serially reusable across mid-tier
threads because they may have some particular state associated with a particular
three-tier user. Examples of such state may include open transactions, the fetch state
from a statement, or a PL/SQL package state. So long as the state exists, the session
is not reusable for a different request.

Note:
Stateless sessions too may have open transactions, open statement fetch
state, and so on. However, such a state persists for a relatively short
duration (only during the processing of a particular three-tier request by a
mid-tier thread) that allows the session to be serially reused for a different
three-tier user (when such state is cleaned up).
Stateless sessions are typically used in conjunction with statement caching.

What connection pooling offers is stateless connections and stateful sessions.

See Also:
Session Pooling in OCI if you must work with stateless sessions

11.4.1.3 Multiple Connection Pools
You can use the advanced concept of multiple connection pools for different database
connections.

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Chapter 11

Connection Pooling in OCI

Multiple connection pools can also be used when different priorities are assigned to
users. Different service-level guarantees can be implemented using connection
pooling.
Figure 11-1 illustrates OCI connection pooling.

Figure 11-1

OCI Connection Pooling

Application
Thread 1

Sessions

Physical
Connections

Thread 2
...

Pool 1

Server 1

Pool 2

Server 2

...
...
...
...
...
...
...
...

11.4.1.4 Transparent Application Failover
Transaction application failover (TAF) is enabled for connection pooling.
The concepts of TAF apply equally well with connections in the connection pool except
that the BACKUP and PRECONNECT clauses should not be used in the connect string and do
not work with connection pooling and TAF.
When a connection in the connection pool fails over, it uses the primary connect string
itself to connect. Sessions fail over when they use the pool for a database round-trip
after their instance failure. The listener is configured to route the connection to a good
instance if available, as is typical with service-based connect strings.

See Also:
Oracle Database Net Services Administrator's Guide, the chapter about
configuring transparent application failover

11.4.2 Using OCI Calls for Connection Pooling
Lists the steps you must follow to use connection pooling in your application.
To use connection pooling in your application, you must:
1.

Allocate the Pool Handle

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Connection Pooling in OCI

2.

Create the Connection Pool

3.

Log On to the Database

4.

Deal with SGA Limitations in Connection Pooling

5.

Log Off from the Database

6.

Destroy the Connection Pool

7.

Free the Pool Handle

11.4.2.1 Allocate the Pool Handle
Connection pooling requires that the pool handle OCI_HTYPE_CPOOL be allocated by
OCIHandleAlloc().
Multiple pools can be created for a given environment handle.
For a single connection pool, here is an allocation example:
OCICPool *poolhp;
OCIHandleAlloc((void *) envhp, (void **) &poolhp, OCI_HTYPE_CPOOL,
(size_t) 0, (void **) 0));

See Also:
OCIHandleAlloc()

11.4.2.2 Create the Connection Pool
The function OCIConnectionPoolCreate() initializes the connection pool handle.
It has these IN parameters:
•

connMin, the minimum number of connections to be opened when the pool is

created.
•

connIncr, the incremental number of connections to be opened when all the

connections are busy and a call needs a connection. This increment is used only
when the total number of open connections is less than the maximum number of
connections that can be opened in that pool.
•

connMax, the maximum number of connections that can be opened in the pool.

When the maximum number of connections are open in the pool, and all the
connections are busy, if a call needs a connection, it waits until it gets one.
However, if the OCI_ATTR_CONN_NOWAIT attribute is set for the pool, an error is
returned.
•

A poolUsername and a poolPassword, to allow user sessions to transparently migrate
between connections in the pool.

•

In addition, an attribute OCI_ATTR_CONN_TIMEOUT, can be set to time out the
connections in the pool. Connections idle for more than this time are terminated
periodically to maintain an optimum number of open connections. If this attribute is
not set, then the connections are never timed out.

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Chapter 11

Connection Pooling in OCI

Note:
Shrinkage of the pool only occurs when there is a network round-trip. If there
are no operations, then the connections stay active.

Because all the preceding attributes can be configured dynamically, the application
can read the current load (number of open connections and number of busy
connections) and tune these attributes appropriately.
If the pool attributes (connMax, connMin, connIncr) are to be changed dynamically,
OCIConnectionPoolCreate() must be called with mode set to OCI_CPOOL_REINITIALIZE.
The OUT parameters poolName and poolNameLen contain values to be used in
subsequent OCIServerAttach() and OCILogon2() calls in place of the database name
and the database name length arguments.
There is no limit on the number of pools that can be created by an application. Middletier applications can create multiple pools to connect to the same server or to different
servers, to balance the load based on the specific needs of the application.
Here is an example of this call:
OCIConnectionPoolCreate((OCIEnv *)envhp,
(OCIError *)errhp, (OCICPool *)poolhp,
&poolName, &poolNameLen,
(text *)database,strlen(database),
(ub4) connMin, (ub4) connMax, (ub4) connIncr,
(text *)poolUsername,strlen(poolUserLen),
(text *)poolPassword,strlen(poolPassLen),
OCI_DEFAULT));

See Also:
•

OCIConnectionPoolCreate()

•

OCI_ATTR_CONN_TIMEOUT

•

OCIServerAttach()

•

OCILogon2()

11.4.2.3 Log On to the Database
The application can use one of several interfaces.
The application must log on to the database for each thread, using one of the following
interfaces.
•

OCILogon2()

This is the simplest interface. Use this interface when you need a simple
connection pool connection and do not need to alter any attributes of the session
handle. This interface can also be used to make proxy connections to the
database.

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Chapter 11

Connection Pooling in OCI

Here is an example using OCILogon2():
for (i = 0; i < MAXTHREADS; ++i)
{
OCILogon2(envhp, errhp, &svchp[i], "hr", 2, "hr", 2, poolName,
poolNameLen, OCI_LOGON2_CPOOL));
}

To use this interface to get a proxy connection, set the password parameter to
NULL.

•

OCISessionGet()

This is the recommended interface. It gives the user the additional option of using
external authentication methods, such as certificates, distinguished name, and so
on. OCISessionGet() is the recommended uniform function call to retrieve a
session.
Here is an example using OCISessionGet():
for (i = 0; i < MAXTHREADS; ++i)
{
OCISessionGet(envhp, errhp, &svchp, authp,
(OraText *) poolName,
strlen(poolName), NULL, 0, NULL, NULL, NULL,
OCI_SESSGET_CPOOL)
}

•

OCIServerAttach() and OCISessionBegin()

You can use another interface if the application must set any special attributes on
the user session handle and server handle. For such a requirement, applications
must allocate all the handles (connection pool handle, server handles, session
handles, and service context handles). You would follow this sequence:
1.

Create the connection pool.
Connection pooling does the multiplexing of a virtual server handle over
physical connections transparently, eliminating the need for users to do so.
The user gets the feeling of a session having a dedicated (virtual) connection.
Because the multiplexing is done transparently to the user, users must not
attempt to multiplex sessions over the virtual server handles themselves. The
concepts of session migration and session switching, which require explicit
multiplexing at the user level, are defunct for connection pooling and should
not be used.

2.

Call OCIServerAttach() with mode set to OCI_CPOOL.
In an OCI program, the user should create (OCIServerAttach() with mode set to
OCI_CPOOL), a unique virtual server handle for each session that is created
using the connection pool. There should be a one-to-one mapping between
virtual server handles and sessions.

3.

Call OCISessionBegin() with mode set to OCI_DEFAULT.
Credentials can be set to OCI_CRED_RDBMS, OCI_CRED_EXT, or OCI_CRED_PROXY
using OCISessionBegin(). If the credentials are set to OCI_CRED_EXT, no user
name and no password need to be set on the session handle. If the
credentials are set to OCI_CRED_PROXY, only the user name must be set on the
session handle. (no explicit primary session must be created and
OCI_ATTR_MIGSESSION need not be set).

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Connection Pooling in OCI

The user should not set OCI_MIGRATE flag in the call to OCISessionBegin() when
the virtual server handle points to a connection pool (OCIServerAttach() called
with mode set to OCI_CPOOL). Oracle supports passing the OCI_MIGRATE flag only
for compatibility reasons. Do not use the OCI_MIGRATE flag, because the
perception that the user gets when using a connection pool is of sessions
having their own dedicated (virtual) connections that are transparently
multiplexed onto real connections.

See Also:
•

OCILogon2()

•

OCISessionGet()

•

OCIServerAttach()

•

OCISessionBegin()

11.4.2.4 Deal with SGA Limitations in Connection Pooling
With OCI_CPOOL mode (connection pooling), the session memory (UGA) in the back-end
database comes out of the SGA.
This may require some SGA tuning on the back-end database to have a larger SGA if
your application consumes more session memory than the SGA can accommodate.
The memory tuning requirements for the back-end database are similar to configuring
the LARGE POOL in a shared server back end except that the instance is still in
dedicated mode.
If you are still running into the SGA limitation, you must consider:
•

Reducing the session memory consumption by having fewer open statements for
each session

•

Reducing the number of sessions in the back end by pooling sessions on the midtier

•

Or otherwise, turning off connection pooling

The application must avoid using dedicated database links on the back end with
connection pooling.
If the back end is a dedicated server, effective connection pooling is not possible
because sessions using dedicated database links are tied to a physical connection
rendering that same connection unusable by other sessions. If your application uses
dedicated database links and you do not see effective sharing of back-end processes
among your sessions, you must consider using shared database links.

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Connection Pooling in OCI

See Also:
•

Oracle Database Performance Tuning Guide, the section about
configuring a shared server

•

Oracle Database Administrator’s Guide, the section on shared database
links for more information about distributed databases

11.4.2.5 Log Off from the Database
Choose the appropriate call to log off from the database in connection pooling mode.
From the following calls, choose the one that corresponds to the logon call and use it
to log off from the database in connection pooling mode.
•

OCILogoff():

If OCILogon2() was used to make the connection, OCILogoff() must be used to log
off.
•

OCISessionRelease()

If OCISessionGet() was called to make the connection, then OCISessionRelease()
must be called to log off.
•

OCISessionEnd() and OCIServerDetach()

If OCIServerAttach() and OCISessionBegin() were called to make the connection
and start the session, then OCISessionEnd() must be called to end the session and
OCIServerDetach() must be called to release the connection.

See Also:
•

OCILogoff()

•

OCILogon2()

•

OCISessionRelease()

•

OCISessionEnd()

•

OCIServerDetach()

•

OCIServerAttach()

•

OCISessionBegin()

11.4.2.6 Destroy the Connection Pool
OCIConnectionPoolDestroy() destroys it.

Use OCIConnectionPoolDestroy() to destroy the connection pool.

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Chapter 11

When to Use Connection Pooling, Session Pooling, or Neither

See Also:
OCIConnectionPoolDestroy()

11.4.2.7 Free the Pool Handle
The pool handle is freed using OCIHandleFree().
These last three actions are illustrated in this code fragment:
for (i = 0; i < MAXTHREADS; ++i)
{
checkerr(errhp, OCILogoff((void *) svchp[i], errhp));
}
checkerr(errhp, OCIConnectionPoolDestroy(poolhp, errhp, OCI_DEFAULT));
checkerr(errhp, OCIHandleFree((void *)poolhp, OCI_HTYPE_CPOOL));

See Also:
•

OCIHandleFree()

•

Connection Pool Handle Attributes

•

OCIConnectionPoolCreate(), OCILogon2(), and
OCIConnectionPoolDestroy()

11.4.3 Examples of OCI Connection Pooling
Where to find examples of connection pooling in tested complete programs.
Examples of connection pooling in tested complete programs can be found in
cdemocp.c and cdemocpproxy.c in directory demo.

11.5 When to Use Connection Pooling, Session Pooling, or
Neither
Indicates the circumstances in which to use them or not.
If database sessions are not reusable by mid-tier threads (that is, they are stateful)
and the number of back-end server processes may cause scaling problems on the
database, use OCI connection pooling.
If database sessions are reusable by mid-tier threads (that is, they are stateless) and
the number of back-end server processes may cause scaling problems on the
database, use OCI session pooling.
If database sessions are not reusable by mid-tier threads (that is, they are stateful)
and the number of back-end server processes is never large enough to potentially
cause any scaling issue on the database, there is no need to use any pooling
mechanism.

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When to Use Connection Pooling, Session Pooling, or Neither

Note:
Having nonpooled sessions or connections results in tearing down and recreating the database session/connection for every mid-tier user request.
This can cause severe scaling problems on the database side and excessive
latency for the fulfillment of the request. Hence, Oracle strongly recommends
that you adopt one of the pooling strategies for mid-tier applications based
on whether the database session is stateful or stateless.

In connection pooling, the pool element is a connection and in session pooling, the
pool element is a session.
As with any pool, the pooled resource is locked by the application thread for a certain
duration until the thread has done its job on the database and the resource is
released. The resource is unavailable to other threads during its period of use. Hence,
application developers must be aware that any kind of pooling works effectively with
relatively short tasks. However, if the application is performing a long-running
transaction, it may deny the pooled resource to other sharers for long periods of time,
leading to starvation. Hence, pooling should be used in conjunction with short tasks,
and the size of the pool should be sufficiently large to maintain the desired
concurrency of transactions.
Note the following additional information about connection pooling and session
pooling:
•

OCI Connection Pooling
Connections to the database are pooled. Sessions are created and destroyed by
the user. Each call to the database picks up an appropriate available connection
from the pool.
The application is multiplexing several sessions over fewer physical connections to
the database. The users can tune the pool configuration to achieve required
concurrency.
The life-time of the application sessions is independent of the life-time of the
cached pooled connections.

•

OCI Session Pooling
Sessions and connections are pooled by OCI. The application gets sessions from
the pool and releases sessions back to the pool.

This section includes the following topics:
•

Functions for Session Creation

•

About Choosing Between Different Types of OCI Sessions

11.5.1 Functions for Session Creation
There are a number of ways to create a session with varying functionality.
OCI offers the following functions for session creation:
•

OCILogin

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When to Use Connection Pooling, Session Pooling, or Neither

OCILogon() is the simplest way to get an OCI session. The advantage is ease of
obtaining an OCI service context. The disadvantage is that you cannot perform
any advance OCI operations, such as session migration, proxy authentication, or
using a connection pool or a session pool.
•

OCILogon2()

OCILogon2() includes the functionality of OCILogon() to get a session. This session
may be a new one with a new underlying connection, or one that is started over a
virtual connection from an existing connection pool, or one from an existing
session pool. The mode parameter value that the function is called with determines
its behavior.
The user cannot modify the attributes (except OCI_ATTR_STMTCACHESIZE) of the
service context returned by OCI.
•

OCISessionBegin()

OCISessionBegin() supports all the various options of an OCI session, such as
proxy authentication, getting a session from a connection pool or a session pool,
external credentials, and migratable sessions. This is the lowest level call, where
all handles must be explicitly allocated and all attributes set. OCIServerAttach()
must be called before this call.
•

OCISessionGet()

OCISessionGet() is now the recommended method to get a session. This session
may be a new one with a new underlying connection, or one that is started over a
virtual connection from an existing connection pool, or one from an existing
session pool. The mode parameter value that the function is called with determines
its behavior. This works like OCILogon2() but additionally enables you to specify
tags for obtaining specific sessions from the pool.

See Also:
•

OCILogon()

•

Application Initialization, Connection, and Session Creation

•

OCILogon2()

•

OCISessionBegin()

•

OCISessionGet()

11.5.2 About Choosing Between Different Types of OCI Sessions
How to choose the type od session to use.
OCI includes the following types of sessions:
•

Basic OCI sessions
The basic OCI session works by using user name and password over a dedicated
OCI server handle. This is the no-pool mechanism. See When to Use Connection
Pooling, Session Pooling, or Neither for information of when to use it.
If authentication is obtained through external credentials, then a user name or
password is not required.

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When to Use Connection Pooling, Session Pooling, or Neither

•

Session pool sessions
Session pool sessions are from the session pool cache. Some sessions may be
tagged. These are stateless sessions. Each OCISessionGet() and
OCISessionRelease() call gets and releases a session from the session cache. This
saves the server from creating and destroying sessions.
See When to Use Connection Pooling, Session Pooling, or Neither on connection
pool sessions versus session pooling sessions versus no-pooling sessions.

•

Connection pool sessions
Connection pool sessions are created using OCISessionGet() and
OCISessionBegin() calls from an OCI connection pool. There is no session cache
as these are stateful sessions. Each call creates a new session, and the user is
responsible for terminating these sessions.
The sessions are automatically migratable between the server handles of the
connection pool. Each session can have user name and password or be a proxy
session. See When to Use Connection Pooling, Session Pooling, or Neither on
connection pool sessions versus session pooling sessions versus no-pooling
sessions.

•

Sessions sharing a server handle
You can multiplex several OCI sessions over a few physical connections. The
application does this manually by having the same server handle for these multiple
sessions. It is preferred to have the session multiplexing details be left to OCI by
using the OCI connection pool APIs.

•

Proxy sessions
Proxy sessions are useful if the password of the client must be protected from the
middle tier. Proxy sessions can also be part of an OCI connection pool or an OCI
session pool.

•

Migratable Sessions

With transaction handles being migratable, there should be no need for applications to
use migratable sessions, instead use OCI connection pooling.

See Also:
•

OCISessionGet()

•

OCISessionRelease()

•

OCISessionBegin()

•

Middle-Tier Applications in OCI for more information about proxy
sessions

•

OCI Session Management

11-26

12
High Availability in OCI
This chapter describes high availability (HA) features in OCI.
This chapter includes the following topics:
•

Runtime Connection Load Balancing

•

HA Event Notification

•

Transparent Application Failover in OCI

•

OCI and Transaction Guard

•

OCI and Application Continuity

12.1 Runtime Connection Load Balancing
Runtime connection load balancing routes work requests to sessions in a session pool
that best serve the work.
It occurs when an application selects a session from an existing session pool and thus
is a very frequent activity. For session pools that support services at one instance only,
the first available session in the pool is adequate. When the pool supports services
that span multiple instances, there is a need to distribute the work requests across
instances so that the instances that are providing better service or have greater
capacity get more requests.
Applications must connect to an Oracle RAC instance to enable runtime connection
load balancing. Furthermore, these applications must:
•

Initialize the OCI Environment in OCI_EVENTS mode

•

Connect to a service that has runtime connection load balancing enabled (use the
DBMS_SERVICE.MODIFY_SERVICE procedure to set GOAL and CLB_GOAL as appropriate)

•

Link with a thread library

See Also:
•

Oracle Real Application Clusters Administration and Deployment Guide
for information about load balancing advisory

•

Oracle Database Development Guide for information about enabling and
disabling runtime connection load balancing for the supported interfaces,
and receiving load balancing advisory FAN events

12-1

Chapter 12

HA Event Notification

12.2 HA Event Notification
Use HA event notification to provide a best-effort programmatic signal to the client if
there is a database failure for high availability clients connected to an Oracle RAC
database.
Suppose that a user employs a web browser to log in to an application server that
accesses a back-end database server. Failure of the database instance can result in a
wait that can be up to minutes in duration before the failure is known to the user. The
ability to quickly detect failures of server instances, communicate this to the client,
close connections, and clean up idle connections in connection pools is provided by
HA event notification.
For high availability clients connected to an Oracle RAC database, you can use HA
event notification to provide a best-effort programmatic signal to the client if there is a
database failure. Client applications can register a callback on the environment handle
to signal interest in this information. When a significant failure event occurs that
applies to a connection made by this client, the callback is invoked, with information
concerning the event (the event payload) and a list of connections (server handles)
that were disconnected because of the failure.
For example, consider a client application that has two connections to instance A and
two connections to instance B of the same database. If instance A goes down, a
notification of the event is sent to the client, which then disconnects the two
connections to instance B and invokes the registered callback. Note that if another
instance C of the same database goes down, the client is not notified (because it does
not affect any of the client's connections).
The HA event notification mechanism improves the response time of the application in
the presence of failure. Before the mechanism was introduced in Oracle Database 10g
Release 2 (10.2), a failure would result in the connection being broken only after the
TCP timeout interval expired, which could take minutes. With HA event notification, the
standalone, connection pool, and session pool connections are automatically broken
and cleaned up by OCI, and the application callback is invoked within seconds of the
failure event. If any of these server handles are TAF-enabled, failover is also
automatically engaged by OCI.
In the current release, this functionality depends on Oracle Notification Service (ONS).
It requires Oracle Clusterware to be installed and configured on the database server
for the clients to receive the HA notifications through ONS. All clusterware installations
(for example, Oracle Data Guard) should have the same ONS port. There is no client
configuration required for ONS.

Note:
The client transparently gets the ONS server information from the database
to which it connects. The application administrator can augment or override
that information using the deployment configuration file oraaccess.xml.

Applications must connect to an Oracle RAC instance to enable HA event notification.
Furthermore, these applications must:
•

Initialize the OCI Environment in OCI_EVENTS mode

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Chapter 12

HA Event Notification

•

Connect to a service that has notifications enabled (use the
DBMS_SERVICE.MODIFY_SERVICE procedure to set AQ_HA_NOTIFICATIONS to TRUE)

•

Link with a thread library

Then these applications can register a callback that is invoked whenever an HA event
occurs.
This section includes the following topics:
•

OCIEvent Handle

•

OCI Failover for Connection and Session Pools

•

OCI Failover for Independent Connections

•

Event Callback

•

Custom Pooling: Tagged Server Handles

•

About Determining Transparent Application Failover (TAF) Capabilities

See Also:
About Client-Side Deployment Parameters Specified in oraaccess.xml for
more information about oraaccess.xml and details about the parameters
under ,  and 

12.2.1 OCIEvent Handle
The OCIEvent handle encapsulates the attributes from the event payload.
OCI implicitly allocates this handle before calling the event callback, which can obtain
the read-only attributes of the event by calling OCIAttrGet(). Memory associated with
these attributes is only valid for the duration of the event callback.

See Also:
•

Event Handle Attributes

•

OCIAttrGet()

12.2.2 OCI Failover for Connection and Session Pools
A connection pool in an instance of Oracle RAC consists of a pool of connections
connected to different instances of Oracle RAC.
Upon receiving the node failure notification, all the connections connected to that
particular instance should be cleaned up. For the connections that are in use, OCI
must close the connections: transparent application failover (TAF) occurs immediately,
and those connections are reestablished. The connections that are idle and in the free
list of the pool must be purged, so that a bad connection is never returned to the user
from the pool.

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HA Event Notification

To accommodate custom connection pools, OCI provides a callback function that can
be registered on the environment handle. If registered, this callback is invoked when
an HA event occurs. Session pools are treated the same way as connection pools.
Note that server handles from OCI connection pools or session pools are not passed
to the callback. Hence in some cases, the callback could be called with an empty list of
connections.

12.2.3 OCI Failover for Independent Connections
No special handling is required for independent connections; all such connections that
are connected to failed instances are immediately disconnected.
For idle connections, TAF is engaged to reestablish the connection when the
connection is used on a subsequent OCI call. Connections that are in use at the time
of the failure event are broken out immediately, so that TAF can begin. Note that this
applies for the "in-use" connections of connection and session pools also.

12.2.4 Event Callback
Shows the signature of the event callback of type OCIEventCallback.
The event callback, of type OCIEventCallback, has the following signature:
void evtcallback_fn (void
*evtctx,
OCIEvent *eventhp );

In this signature evtctx is the client context, and OCIEvent is an event handle that is
opaque to the OCI library. The other input argument is eventhp, the event handle (the
attributes associated with an event).
If registered, this function is called once for each event. For Oracle RAC HA events,
this callback is invoked after the affected connections have been disconnected. The
following environment handle attributes are used to register an event callback and
context, respectively:
•

OCI_ATTR_EVTCBK is of data type OCIEventCallback *. It is read-only.

•

OCI_ATTR_EVTCTX is of data type void *. It is also read-only.

text *myctx = "dummy context"; /* dummy context passed to callback fn */
...
/* OCI_ATTR_EVTCBK and OCI_ATTR_EVTCTX are read-only. */
OCIAttrSet(envhp, (ub4) OCI_HTYPE_ENV, (void *) evtcallback_fn,
(ub4) 0, (ub4) OCI_ATTR_EVTCBK, errhp);
OCIAttrSet(envhp, (ub4) OCI_HTYPE_ENV, (void *) myctx,
(ub4) 0, (ub4) OCI_ATTR_EVTCTX, errhp);
...

Within the OCI event callback, the list of affected server handles is encapsulated in the
OCIEvent handle. For Oracle RAC HA DOWN events, client applications can iterate
over a list of server handles that are affected by the event by using OCIAttrGet() with
attribute types OCI_ATTR_HA_SRVFIRST and OCI_ATTR_HA_SRVNEXT:
OCIAttrGet(eventhp, OCI_HTYPE_EVENT, (void *)&srvhp, (ub4 *)0,
OCI_ATTR_HA_SRVFIRST, errhp);
/* or, */
OCIAttrGet(eventhp, OCI_HTYPE_EVENT, (void *)&srvhp, (ub4 *)0,
OCI_ATTR_HA_SRVNEXT, errhp);

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HA Event Notification

When called with attribute OCI_ATTR_HA_SRVFIRST, this function retrieves the first server
handle in the list of server handles affected. When called with attribute
OCI_ATTR_HA_SRVNEXT, this function retrieves the next server handle in the list. This
function returns OCI_NO_DATA and srvhp is a NULL pointer, when there are no more server
handles to return.
srvhp is an output pointer to a server handle whose connection has been closed
because of an HA event. errhp is an error handle to populate. The application returns
an OCI_NO_DATA error when there are no more affected server handles to retrieve.

When retrieving the list of server handles that have been affected by an HA event, be
aware that the connection has already been closed and many server handle attributes
are no longer valid. Instead, use the user memory segment of the server handle to
store any per-connection attributes required by the event notification callback. This
memory remains valid until the server handle is freed.

See Also:
OCIAttrGet()

12.2.5 Custom Pooling: Tagged Server Handles
Using custom pools, you can retrieve the server handle’s tag information so
appropriate cleanup can be performed.
The following features apply to custom pools:
•

You can tag a server handle with its parent connection object if it is created on
behalf of a custom pool. Use the "user memory" parameters of OCIHandleAlloc() to
request that the server handle be allocated with a user memory segment. A
pointer to the "user memory" segment is returned by OCIHandleAlloc().

•

When an HA event occurs and an affected server handle has been retrieved, there
is a means to retrieve the server handle's tag information so appropriate cleanup
can be performed. The attribute OCI_ATTR_USER_MEMORY is used to retrieve a pointer
to a handle's user memory segment. OCI_ATTR_USER_MEMORY is valid for all userallocated handles. If the handle was allocated with extra memory, this attribute
returns a pointer to the user memory. A NULL pointer is returned for those handles
not allocated with extra memory. This attribute is read-only and is of data type
void*.

Note:
You are free to define the precise contents of the server handle's user
memory segment to facilitate cleanup activities from within the HA event
callback (or for other purposes if needed) because OCI does not write or
read from this memory in any way. The user memory segment is freed with
the OCIHandleFree() call on the server handle.

Example 12-1 shows an example of event notification.

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HA Event Notification

Example 12-1

Event Notification

sword retval;
OCIServer *srvhp;
struct myctx {
void *parentConn_myctx;
uword numval_myctx;
};
typedef struct myctx myctx;
myctx *myctxp;
/* Allocate a server handle with user memory - pre 10.2 functionality */
if (retval = OCIHandleAlloc(envhp, (void **)&srvhp, OCI_HTYPE_SERVER,
(size_t)sizeof(myctx), (void **)&myctxp)
/* handle error */
myctxp->parentConn_myctx = ;
/* In an event callback function, retrieve the pointer to the user memory */
evtcallback_fn(void *evtctx, OCIEvent *eventhp)
{
myctx *ctxp = (myctx *)evtctx;
OCIServer *srvhp;
OCIError *errhp;
sb4
retcode;
retcode = OCIAttrGet(eventhp, OCI_HTYPE_SERVER, &srvhp, (ub4 *)0,
OCI_ATTR_HA_SRVFIRST, errhp);
while (!retcode) /* OCIAttrGet will return OCI_NO_DATA if no more srvhp */
{
OCIAttrGet((void *)srvhp, OCI_HTYPE_SERVER, (void *)&ctxp,
(ub4)0, (ub4)OCI_ATTR_USER_MEMORY, errhp);
/* Remove the server handle from the parent connection object */
retcode = OCIAttrGet(eventhp, OCI_HTYPE_SERVER, &srvhp, (ub4 *)0,
OCI_ATTR_HA_SRVNEXT, errhp);
...
}
...
}

See Also:
•

OCIHandleAlloc()

•

OCIHandleFree()

12.2.6 About Determining Transparent Application Failover (TAF)
Capabilities
You can have the application adjust its behavior if a connection is or is not TAFenabled.
Use OCIAttrGet() as follows to determine if a server handle is TAF-enabled:
boolean taf_capable;
...
OCIAttrGet(srvhp, (ub4) OCI_HTYPE_SERVER, (void *) &taf_capable,
(ub4) sizeof(taf_capable), (ub4)OCI_ATTR_TAF_ENABLED, errhp);
...

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In this example, taf_capable is a Boolean variable, which this call sets to TRUE if the
server handle is TAF-enabled, and FALSE if not; srvhp is an input target server handle;
OCI_ATTR_TAF_ENABLED is an attribute that is a pointer to a Boolean variable and is readonly; errhp is an input error handle.

12.3 Transparent Application Failover in OCI
Transparent application failover (TAF) is a client-side feature designed to minimize
disruptions to end-user applications that occur when database connectivity fails
because of instance or network failure.
TAF can be implemented on a variety of system configurations including Oracle Real
Application Clusters (Oracle RAC) and Oracle Data Guard physical standby
databases. TAF can also be used after restarting a single instance system (for
example, when repairs are made).
TAF can be configured to restore database sessions and optionally, to replay open
queries. Starting with Oracle Database 10g Release 2 (10.2) all statements that an
application attempts to use after a failure attempt failover. That is, an attempt to
execute or fetch against other statements engages TAF recovery just as for the failuretime statement. Subsequent statements may now succeed (whereas in the past they
failed), or the application may receive errors corresponding to an attempted TAF
recovery (such as ORA-25401).

Note:
Oracle recommends for applications to register a callback, so when failover
happens, the callback can be used to restore the session to the desired
state.

Note:
TAF is not supported for remote database links or for DML statements.

This section contains the following topics:
•

About Configuring Transparent Application Failover

•

Transparent Application Failover Callbacks in OCI

•

Transparent Application Failover Callback Structure and Parameters

•

Failover Callback Structure and Parameters

•

Failover Callback Registration

•

Failover Callback Example

•

Handling OCI_FO_ERROR

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Transparent Application Failover in OCI

12.3.1 About Configuring Transparent Application Failover
TAF can be configured on both the client side and the server side. If both are
configured, server-side settings take precedence.
Configure TAF on the client side by including the FAILOVER_MODE parameter in the
CONNECT_DATA portion of a connect descriptor.
Configure TAF on the server side by modifying the target service with the
DBMS_SERVICE.MODIFY_SERVICE packaged procedure.

An initial attempt at failover may not always succeed. OCI provides a mechanism for
retrying failover after an unsuccessful attempt.

See Also:
•

Oracle Database Net Services Reference for more information about
client-side configuration of TAF (Connect Data Section)

•

Oracle Database PL/SQL Packages and Types Reference for more
information about the server-side configuration of TAF
(DBMS_SERVICE)

12.3.2 Transparent Application Failover Callbacks in OCI
Because of the delay that can occur during failover, the application developer may
want to inform the user that failover is in progress, and request that the user wait for
notification that failover is complete.
Additionally, the session on the initial instance may have received some ALTER SESSION
commands. These ALTER SESSION commands are not automatically replayed on the
second instance. Consequently, the developer may want to replay them on the second
instance. OCIAttrSet() calls that affect the session must also be reexecuted.
To accommodate these requirements, the application developer can register a failover
callback function. If failover occurs, the callback function is invoked several times while
reestablishing the user's session.
The first call to the callback function occurs when the database first detects an
instance connection loss. This callback is intended to allow the application to inform
the user of an upcoming delay. If failover is successful, a second call to the callback
function occurs when the connection is reestablished and usable.
Once the connection has been reestablished, the client may want to replay ALTER
SESSION commands and inform the user that failover has happened. If failover is
unsuccessful, then the callback is called to inform the application that failover cannot
occur. Additionally, the callback is called each time a user handle besides the primary
handle is reauthenticated on the new connection. Because each user handle
represents a server-side session, the client may want to replay ALTER SESSION
commands for that session.

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Transparent Application Failover in OCI

See Also:
•

OCIAttrSet()

•

Handling OCI_FO_ERROR for more information about this scenario

12.3.3 Transparent Application Failover Callback Structure and
Parameters
Describes the TAF Callback structure and parameters.
The basic structure of a Transparent Application Failover (TAF) callback function is as
follows:
sb4 TAFcbk_fn(OCISvcCtx *svchp,
OCIEnv
*envhp,
void
*fo_ctx,
ub4
fo_type,
ub4
fo_event);

svchp
The service context handle.
envhp
The OCI environment handle.
fo_ctx
The client context. This is a pointer to memory specified by the client. In this area the
client can keep any necessary state or context.
fo_type
The failover type. This lets the callback know what type of failover the client has
requested. The usual values are as follows:
•

OCI_FO_SESSION indicates that the user has requested only session failover.

•

OCI_FO_SELECT indicates that the user has requested select failover as well.

fo_event
The failover event indicates the current status of the failover.
•

OCI_FO_BEGIN indicates that failover has detected a lost connection and failover is

starting.
•

OCI_FO_END indicates successful completion of failover.

•

OCI_FO_ABORT indicates that failover was unsuccessful, and there is no option of

retrying.
•

OCI_FO_ERROR also indicates that failover was unsuccessful, but it gives the

application the opportunity to handle the error and retry failover.

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Transparent Application Failover in OCI

•

OCI_FO_REAUTH indicates that you have multiple authentication handles and failover

has occurred after the original authentication. It indicates that a user handle has
been reauthenticated. To determine which one, the application checks the
OCI_ATTR_SESSION attribute of the service context handle svchp.
If Application Continuity is configured, the TAF callback is called with OCI_FO_END after
successfully re-connecting, re-authenicating, and determining the status of the inflight
transaction.
Upon completion of the TAF callback, OCI returns an error if an open transaction is
present and Application Continuity for OCI is enabled.

12.3.4 Failover Callback Structure and Parameters
Shows and describes the basic structure of a user-defined application failover callback
function.
The basic structure of a user-defined application failover callback function is as
follows:
sb4 appfocallback_fn ( void
void
void
ub4
ub4

* svchp,
* envhp,
* fo_ctx,
fo_type,
fo_event );

An example is provided in "Failover Callback Example" on page 9‐31 for the following
parameters:
svchp
The first parameter, svchp, is the service context handle. It is of type void *.
envhp
The second parameter, envhp, is the OCI environment handle. It is of type void *.
fo_ctx
The third parameter, fo_ctx, is a client context. It is a pointer to memory specified by
the client. In this area the client can keep any necessary state or context. It is passed
as a void *.
fo_type
The fourth parameter, fo_type, is the failover type. This lets the callback know what
type of failover the client has requested. The usual values are as follows:
•

OCI_FO_SESSION indicates that the user has requested only session failover.

•

OCI_FO_SELECT indicates that the user has requested select failover as well.

fo_event
The last parameter is the failover event. This indicates to the callback why it is being
called. It has several possible values:
•

OCI_FO_BEGIN indicates that failover has detected a lost connection and failover is

starting.
•

OCI_FO_END indicates successful completion of failover.

•

OCI_FO_ABORT indicates that failover was unsuccessful, and there is no option of

retrying.

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Transparent Application Failover in OCI

•

OCI_FO_ERROR also indicates that failover was unsuccessful, but it gives the

application the opportunity to handle the error and retry failover.
•

OCI_FO_REAUTH indicates that you have multiple authentication handles and failover

has occurred after the original authentication. It indicates that a user handle has
been reauthenticated. To determine which one, the application checks the
OCI_ATTR_SESSION attribute of the service context handle (which is the first
parameter).

12.3.5 Failover Callback Registration
For the failover callback to be used, it must be registered on the server context handle.
This registration is done by creating a callback definition structure and setting the
OCI_ATTR_FOCBK attribute of the server handle to this structure.
The callback definition structure must be of type OCIFocbkStruct. It has two fields:
callback_function, which contains the address of the function to call, and fo_ctx, which
contains the address of the client context.

See Also:
Example 12-3 for an example of callback registration

12.3.6 Failover Callback Example
Shows several failover callback examples.
This section shows an example of a simple user-defined callback function definition
(see Example 12-2), failover callback registration (see Example 12-3), and failover
callback unregistration (see Example 12-4).
Example 12-2

User-Defined Failover Callback Function Definition

sb4 callback_fn(svchp, envhp, fo_ctx, fo_type, fo_event)
void * svchp;
void * envhp;
void *fo_ctx;
ub4 fo_type;
ub4 fo_event;
{
switch (fo_event)
{
case OCI_FO_BEGIN:
{
printf(" Failing Over ... Please stand by \n");
printf(" Failover type was found to be %s \n",
((fo_type==OCI_FO_SESSION) ? "SESSION"
:(fo_type==OCI_FO_SELECT) ? "SELECT"
: "UNKNOWN!"));
printf(" Failover Context is :%s\n",
(fo_ctx?(char *)fo_ctx:"NULL POINTER!"));
break;
}
case OCI_FO_ABORT:
{
printf(" Failover stopped. Failover will not occur.\n");

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break;
}
case
OCI_FO_END:
{
printf(" Failover ended ...resuming services\n");
break;
}
case OCI_FO_REAUTH:
{
printf(" Failed over user. Resuming services\n");
break;
}
default:
{
printf("Bad Failover Event: %d.\n", fo_event);
break;
}
}
return 0;
}

Example 12-3

Failover Callback Registration

int register_callback(srvh, errh)
void *srvh; /* the server handle */
OCIError *errh; /* the error handle */
{
OCIFocbkStruct failover;
/* failover callback structure */
/* allocate memory for context */
if (!(failover.fo_ctx = (void *)malloc(strlen("my context.")+1)))
return(1);
/* initialize the context. */
strcpy((char *)failover.fo_ctx, "my context.");
failover.callback_function = &callback_fn;
/* do the registration */
if (OCIAttrSet(srvh, (ub4) OCI_HTYPE_SERVER,
(void *) &failover, (ub4) 0,
(ub4) OCI_ATTR_FOCBK, errh) != OCI_SUCCESS)
return(2);
/* successful conclusion */
return (0);
}

Example 12-4

Failover Callback Unregistration

OCIFocbkStruct failover;
sword status;

/* failover callback structure */

/* set the failover context to null */
failover.fo_ctx = NULL;
/* set the failover callback to null */
failover.callback_function = NULL;
/* unregister the callback */
status = OCIAttrSet(srvhp, (ub4) OCI_HTYPE_SERVER,
(void *) &failover, (ub4) 0,
(ub4) OCI_ATTR_FOCBK, errhp);

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12.3.7 Handling OCI_FO_ERROR
A failover attempt is not always successful. If the attempt fails, the callback function
receives a value of OCI_FO_ABORT or OCI_FO_ERROR in the fo_event parameter.
A value of OCI_FO_ABORT indicates that failover was unsuccessful, and no further failover
attempts are possible. OCI_FO_ERROR, however, provides the callback function with the
opportunity to handle the error. For example, the callback may choose to wait a
specified period of time and then indicate to the OCI library that it must reattempt
failover.

Note:
This functionality is only available to applications linked with the 8.0.5 or later
OCI libraries running against any Oracle Database server.
Failover does not work if a LOB column is part of the select list.

Consider the timeline of events presented in Table 12-1.
Table 12-1

Time and Event

Time

Event

T0

Database fails (failure lasts until T5).

T1

Failover is triggered by user activity.

T2

User attempts to reconnect; attempt fails.

T3

Failover callback is invoked with OCI_FO_ERROR.

T4

Failover callback enters a predetermined sleep period.

T5

Database comes back up again.

T6

Failover callback triggers a new failover attempt; it is successful.

T7

User successfully reconnects.

The callback function triggers the new failover attempt by returning a value of
OCI_FO_RETRY from the function.
Example 12-5 shows a callback function that you can use to implement the failover
strategy similar to the scenario described earlier. In this case, the failover callback
enters a loop in which it sleeps and then reattempts failover until it is successful:
Example 12-5

Callback Function That Implements a Failover Strategy

/*--------------------------------------------------------------------*/
/* the user-defined failover callback */
/*--------------------------------------------------------------------*/
sb4 callback_fn(svchp, envhp, fo_ctx, fo_type, fo_event )
void * svchp;
void * envhp;
void *fo_ctx;
ub4 fo_type;
ub4 fo_event;

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OCI and Transaction Guard

{
OCIError *errhp;
OCIHandleAlloc(envhp, (void **)&errhp, (ub4) OCI_HTYPE_ERROR,
(size_t) 0, (void **) 0);
switch (fo_event)
{
case OCI_FO_BEGIN:
{
printf(" Failing Over ... Please stand by \n");
printf(" Failover type was found to be %s \n",
((fo_type==OCI_FO_NONE) ? "NONE"
:(fo_type==OCI_FO_SESSION) ? "SESSION"
:(fo_type==OCI_FO_SELECT) ? "SELECT"
:(fo_type==OCI_FO_TXNAL) ? "TRANSACTION"
: "UNKNOWN!"));
printf(" Failover Context is :%s\n",
(fo_ctx?(char *)fo_ctx:"NULL POINTER!"));
break;
}
case OCI_FO_ABORT:
{
printf(" Failover aborted. Failover will not occur.\n");
break;
}
case
OCI_FO_END:
{
printf("\n Failover ended ...resuming services\n");
break;
}
case OCI_FO_REAUTH:
{
printf(" Failed over user. Resuming services\n");
break;
}
case OCI_FO_ERROR:
{
/* all invocations of this can only generate one line. The newline
* will be put at fo_end time.
*/
printf(" Failover error gotten. Sleeping...");
sleep(3);
printf("Retrying. ");
return (OCI_FO_RETRY);
break;
}
default:
{
printf("Bad Failover Event: %d.\n", fo_event);
break;
}
}
return 0;
}

12.4 OCI and Transaction Guard
Transaction Guard introduces the concept of at-most-once transaction execution in
case of a planned or unplanned outage to help prevent an application upon failover
from submitting a duplicate submission of an original submission.

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When an application opens a connection to the database using this service, the logical
transaction ID (LTXID) is generated at authentication and stored in the session handle.
This is a globally unique ID that identifies the database transaction from the application
perspective. When there is an outage, an application using Transaction Guard can
retrieve the LTXID from the previous failed session's handle and use it to determine
the outcome of the transaction that was active prior to the session failure. If the LTXID
is determined to be unused, then the application can replay an uncommitted
transaction by first blocking the original submission using the retrieved LTXID. If the
LTXID is determined to be used, then the transaction is committed and the result is
returned to the application.
Transaction Guard is a developer API supported for JDBC Type 4 (Oracle Thin), OCI,
OCCI, and Oracle Data Provider for .NET (ODP.NET) drivers. For OCI, when an
application is written to support Transaction Guard, upon an outage, the OCI client
driver acquires and retrieves the LTXID from the previous failed session's handle by
calling OCI_ATTR_GET() using the OCI_ATTR_LTXID session handle attribute.
This section includes the following topic: Developing Applications that Use Transaction
Guard.

See Also:
Oracle Database Development Guide for information in the chapter about
using Transaction Guard in for an overview of Transaction Guard, supported
transaction types, transaction types that are not supported, and database
configuration information for using Transaction Guard.

12.4.1 Developing Applications that Use Transaction Guard
This section describes developing OCI user applications that use Transaction Guard.
See the chapter about using Transaction Guard in Oracle Database Development
Guide for more detailed information about developing applications using Transaction
Guard.
For the third-party or user application to use Transaction Guard in order to be able to
fail over a session for OCI, it must include several major steps:
1.

2.

Verify if Transparent Application Failover (TAF) is enabled for the connection. Do
not attempt to explicitly use Transaction Guard on a TAF-enabled connection, as
TAF will automatically check the LTXID.
On receipt of an error, determine whether the error is a recoverable error OCI_ATTR_ERROR_IS_RECOVERABLE on OCI_ERROR handle. If the error is recoverable,

then continue to Step 3.

Note:
Do not attempt to use the LTXID to check transaction outcome if the
connection has not suffered a recoverable error.

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OCI and Transaction Guard

3.

Retrieve the LTXID associated with the failed session by using OCI_ATTR_GET()
to get the OCI_ATTR_LTXID from the user session handle.

4.

Reconnect to the database.

Note:
The new session will have a new LTXID, but you will not need it when
checking the status of the original session.
5.

Invoke the DBMS_APP_CONT.GET_LTXID_OUTCOME PL/SQL procedure with the LTXID
obtained from the OCI_ATTR_GET() call. The original LTXID of the failed-over
session is marked as forced if that LTXID has not been used. The return state tells
the driver if the last transaction was COMMITTED (TRUE/FALSE) and
USER_CALL_COMPLETED (TRUE/FALSE).

6.

The application can replay an uncommitted transaction or return the result to the
user. If the replay itself incurs an outage, then the LTXID for the replaying session
is used for the DBMS_APP_CONT.GET_LTXID_OUTCOME procedure.

See the following sections for Transaction Guard usage and examples:
•

Typical Transaction Guard Usage

•

Transaction Guard Examples

12.4.1.1 Typical Transaction Guard Usage
Shows typical usage of Transaction Guard using pseudocode.
The following pseudocode shows a typical usage of Transaction Guard:
1.

Receive a FAN down event (or recoverable error)

2.

FAN aborts the dead session

3.

Call OCIAttrGet() using the OCI_ATTR_TAF_ENABLED attribute on the server handle. If
the value is TRUE, stop. If the value is FALSE, proceed to the next step.

4.

If it is a recoverable error, for OCI (OCI_ATTR_ERROR_IS_RECOVERABLE on OCI_ERROR
handle):
a.

Get the last LTXID from the dead session by calling OCIAttrGet() using the
OCI_ATTR_LTXID session handle attribute to retrieve the LTXID associated with
the session's handle

5.

b.

Obtain a new session

c.

Call DBMS_APP_CONT.GET_LTXID_OUTCOME with the last LTXID to get the return
state

If the return state is:
a.

COMMITTED and USER_CALL_COMPLETED

Then return the result.
b.

ELSEIF COMMITTED and NOT USER_CALL_COMPLETED

Then return the result with a warning (with details, such as out binds or row
count was not returned).

12-16

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OCI and Transaction Guard

c.

ELSEIF NOT COMMITTED

Resubmit the transaction or series of calls or both, or return error to user.

See Also:
OCIAttrGet()

12.4.1.2 Transaction Guard Examples
Shows a Transaction Guard demo program.
Example 12-6 is an OCI Transaction Guard demo program (cdemotg.c) that
demonstrates:
•

Use of the attribute OCI_ATTR_ERROR_IS_RECOVERABLE. When an error occurs, the
program checks if the error is recoverable.

•

Use of the packaged procedure DBMS_APP_CONT.GET_LTXID_OUTCOME. If the error is
recoverable, the program calls DBMS_APP_CONT.GET_LTXID_OUTCOME to determine the
status of the active transaction.

If the transaction has not committed, the program re-executes the failed transaction.

Note:
This program does not modify the session state such as NLS parameters,
and so forth. Programs that do so may need to reexecute such commands
after obtaining a new session from the pool following the error.

Example 12-6

Transaction Guard Demo Program

*/
#ifndef OCISP_ORACLE
# include 
#endif
/* Maximum Number of threads */
#define MAXTHREAD 1
static ub4 sessMin = 1;
static ub4 sessMax = 9;
static ub4 sessIncr = 2;
static
static
static
static

OCIError *errhp;
OCIEnv
*envhp;
OCISPool *poolhp=(OCISPool *) 0;
int employeeNum[MAXTHREAD];

static
static
static
static
static

OraText *poolName;
ub4 poolNameLen;
CONST OraText *database = (text *)"ltxid_service";
CONST OraText *appusername =(text *)"scott";
CONST OraText *apppassword =(text *)"tiger";

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OCI and Transaction Guard

static CONST char getLtxid[]=
("BEGIN DBMS_APP_CONT.GET_LTXID_OUTCOME ("
":ltxid,:committed,:callComplete); END;");
static CONST char insertst1[] =
("INSERT INTO EMP(ENAME, EMPNO) values ('NAME1', 1000)");
static void checkerr (OCIError *errhp, sword status);
static void threadFunction (dvoid *arg);
int main(void)
{
int i = 0;
sword lstat;
int timeout =1;
OCIEnvCreate (&envhp, OCI_THREADED, (dvoid *)0, NULL,
NULL, NULL, 0, (dvoid *)0);
(void) OCIHandleAlloc((dvoid *) envhp, (dvoid **) &errhp, OCI_HTYPE_ERROR,
(size_t) 0, (dvoid **) 0);
(void) OCIHandleAlloc((dvoid *) envhp, (dvoid **) &poolhp, OCI_HTYPE_SPOOL,
(size_t) 0, (dvoid **) 0);
/* Create the session pool */
checkerr(errhp, OCIAttrSet((dvoid *) poolhp,
(ub4) OCI_HTYPE_SPOOL, (dvoid *) &timeout, (ub4)0,
OCI_ATTR_SPOOL_TIMEOUT, errhp));
if (lstat = OCISessionPoolCreate(envhp, errhp,poolhp, (OraText **)&poolName,
(ub4 *)&poolNameLen, database,
(ub4)strlen((const char *)database),
sessMin, sessMax, sessIncr,
(OraText *)appusername,
(ub4)strlen((const char *)appusername),
(OraText *)apppassword,
(ub4)strlen((const char *)apppassword),
OCI_SPC_STMTCACHE|OCI_SPC_HOMOGENEOUS))
{
checkerr(errhp,lstat);
}
printf("Session Pool Created \n");
/* Multiple threads using the session pool */
{
OCIThreadId *thrid[MAXTHREAD];
OCIThreadHandle *thrhp[MAXTHREAD];
OCIThreadProcessInit ();
checkerr (errhp, OCIThreadInit (envhp, errhp));
for (i = 0; i < MAXTHREAD; ++i)
{
checkerr (errhp, OCIThreadIdInit (envhp, errhp, &thrid[i]));
checkerr (errhp, OCIThreadHndInit (envhp, errhp, &thrhp[i]));
}
for (i = 0; i < MAXTHREAD; ++i)
{
employeeNum[i]=i;
/* Inserting into EMP table */

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Chapter 12

OCI and Transaction Guard

checkerr (errhp, OCIThreadCreate (envhp, errhp, threadFunction,
(dvoid *) &employeeNum[i], thrid[i], thrhp[i]));
}
for (i = 0; i < MAXTHREAD; ++i)
{
checkerr (errhp, OCIThreadJoin (envhp, errhp, thrhp[i]));
checkerr (errhp, OCIThreadClose (envhp, errhp, thrhp[i]));
checkerr (errhp, OCIThreadIdDestroy (envhp, errhp, &(thrid[i])));
checkerr (errhp, OCIThreadHndDestroy (envhp, errhp, &(thrhp[i])));
}
checkerr (errhp, OCIThreadTerm (envhp, errhp));
} /* ALL THE THREADS ARE COMPLETE */
lstat = OCISessionPoolDestroy(poolhp, errhp, OCI_DEFAULT);
printf("Session Pool Destroyed \n");
if (lstat != OCI_SUCCESS)
checkerr(errhp, lstat);
checkerr(errhp, OCIHandleFree((dvoid *)poolhp, OCI_HTYPE_SPOOL));
checkerr(errhp, OCIHandleFree((dvoid *)errhp, OCI_HTYPE_ERROR));
return 0;
} /* end of main () */
/* Inserts records into EMP table */
static void threadFunction (dvoid *arg)
{
int empno = *(int *)arg;
OCISvcCtx *svchp = (OCISvcCtx *) 0;
OCISvcCtx *svchp2 = (OCISvcCtx *) 0;
OCISession *embUsrhp = (OCISession *)0;
OCIBind *bnd1p, *bnd2p, *bnd3p;
OCIStmt *stmthp = (OCIStmt *)0;
OCIStmt *getLtxidStm = (OCIStmt *)0;
OCIError *errhp2 = (OCIError *) 0;
OCIAuthInfo *authp = (OCIAuthInfo *)0;
sword lstat;
text name[10];
boolean callCompl, committed, isRecoverable;
ub1 *myLtxid;
ub4 myLtxidLen;
ub4 numAttempts = 0;
(void) OCIHandleAlloc((dvoid *) envhp, (dvoid **) &errhp2, OCI_HTYPE_ERROR,
(size_t) 0, (dvoid **) 0);
lstat = OCIHandleAlloc((dvoid *) envhp,
(dvoid **)&authp, (ub4) OCI_HTYPE_AUTHINFO,
(size_t) 0, (dvoid **) 0);
if (lstat)
checkerr(errhp2, lstat);
checkerr(errhp2, OCIAttrSet((dvoid *) authp,(ub4) OCI_HTYPE_AUTHINFO,
(dvoid *) appusername, (ub4) strlen((char *)appusername),
(ub4) OCI_ATTR_USERNAME, errhp2));

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OCI and Transaction Guard

checkerr(errhp2,OCIAttrSet((dvoid *) authp,(ub4) OCI_HTYPE_AUTHINFO,
(dvoid *) apppassword, (ub4) strlen((char *)apppassword),
(ub4) OCI_ATTR_PASSWORD, errhp2));
restart:
if (lstat = OCISessionGet(envhp, errhp2, &svchp, authp,
(OraText *)poolName, (ub4)strlen((char *)poolName), NULL,
0, NULL, NULL, NULL, OCI_SESSGET_SPOOL))
{
checkerr(errhp2,lstat);
}
/* save the ltxid from the session in case we need to call
* get_ltxid_outcome to determine the transaction status.
*/
checkerr(errhp2, OCIAttrGet(svchp, OCI_HTYPE_SVCCTX,
(dvoid *)&embUsrhp, (ub4 *)0,
(ub4)OCI_ATTR_SESSION, errhp2));
checkerr(errhp2, OCIAttrGet(embUsrhp, OCI_HTYPE_SESSION,
(dvoid *)&myLtxid, (ub4 *)&myLtxidLen,
(ub4)OCI_ATTR_LTXID, errhp2));

/* */
checkerr(errhp2, OCIStmtPrepare2(svchp, &stmthp, errhp2,
(CONST OraText *)insertst1,
(ub4)sizeof(insertst1),
(const oratext *)0, (ub4)0,
OCI_NTV_SYNTAX, OCI_DEFAULT));
if (!numAttempts)
{
char input[1];
printf("Kill SCOTT's session now. Press ENTER when complete\n");
gets(input);
}
lstat = OCIStmtExecute (svchp, stmthp, errhp2, (ub4)1, (ub4)0,
(OCISnapshot *)0, (OCISnapshot *)0,
OCI_DEFAULT );
if (lstat == OCI_ERROR)
{
checkerr(errhp2, OCIAttrGet(errhp2, OCI_HTYPE_ERROR,
(dvoid *)&isRecoverable, (ub4 *)0,
(ub4)OCI_ATTR_ERROR_IS_RECOVERABLE, errhp2));
if (isRecoverable)
{
printf("Recoverable error occurred; checking transaction status.\n");
/* get another session to use for the get_ltxid_outcome call */
if (lstat = OCISessionGet(envhp, errhp2, &svchp2, authp,
(OraText *)poolName,
(ub4)strlen((char *)poolName), NULL,
0, NULL, NULL, NULL, OCI_SESSGET_SPOOL))
{
checkerr(errhp2,lstat);
}
checkerr(errhp2,OCIStmtPrepare2(svchp2,&getLtxidStm, errhp2,
(CONST OraText *)getLtxid,
(ub4)sizeof(getLtxid),

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Chapter 12

OCI and Transaction Guard

(const oratext *)0, (ub4)0,
OCI_NTV_SYNTAX, OCI_DEFAULT));
checkerr(errhp, OCIBindByPos(getLtxidStm, &bnd1p, errhp, 1,
(dvoid *) myLtxid, (sword)myLtxidLen,
SQLT_BIN, (dvoid *)0,
(ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0,
OCI_DEFAULT));
checkerr(errhp, OCIBindByPos(getLtxidStm, &bnd2p, errhp, 2,
(dvoid *) &committed,
(sword)sizeof(committed),
SQLT_BOL, (dvoid *)0,
(ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0,
OCI_DEFAULT));
checkerr(errhp, OCIBindByPos(getLtxidStm, &bnd3p, errhp, 3,
(dvoid *) &callCompl,
(sword)sizeof(callCompl),
SQLT_BOL, (dvoid *)0,
(ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4 *) 0,
OCI_DEFAULT));
checkerr(errhp2,OCIStmtExecute(svchp2, getLtxidStm, errhp2,
(ub4)1, (ub4)0,
(OCISnapshot *)0, (OCISnapshot *)0,
OCI_DEFAULT ));
checkerr(errhp2, OCISessionRelease(svchp2, errhp2,
NULL, 0, OCI_DEFAULT));
if (committed && callCompl)
printf("Insert successfully commited \n");
else if (!committed)
{
printf("Transaction did not commit; re-executing last transaction\n");
numAttempts++;
/* As there was an outage, do not return this session to the pool */
checkerr(errhp2,
OCISessionRelease(svchp, errhp2,
NULL, 0, OCI_SESSRLS_DROPSESS));
svchp = (OCISvcCtx *)0;
goto restart;
}
}
}
else
{
checkerr(errhp2, OCITransCommit(svchp,errhp2,(ub4)0));
printf("Transaction committed successfully\n");
}
if (stmthp)
checkerr(errhp2, OCIStmtRelease((dvoid *) stmthp, errhp2,
(void *)0, 0, OCI_DEFAULT));
if (getLtxidStm)
checkerr(errhp2, OCIStmtRelease((dvoid *) getLtxidStm, errhp2,
(void *)0, 0, OCI_DEFAULT));
if (svchp)
checkerr(errhp2, OCISessionRelease(svchp, errhp2, NULL, 0, OCI_DEFAULT));
OCIHandleFree((dvoid *)authp, OCI_HTYPE_AUTHINFO);
OCIHandleFree((dvoid *)errhp2, OCI_HTYPE_ERROR);
} /* end of threadFunction (dvoid *) */

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OCI and Application Continuity

/* This function prints the error */
void checkerr(errhp, status)
OCIError *errhp;
sword status;
{
text errbuf[512];
sb4 errcode = 0;
switch (status)
{
case OCI_SUCCESS:
break;
case OCI_SUCCESS_WITH_INFO:
(void) printf("Error - OCI_SUCCESS_WITH_INFO\n");
break;
case OCI_NEED_DATA:
(void) printf("Error - OCI_NEED_DATA\n");
break;
case OCI_NO_DATA:
(void) printf("Error - OCI_NODATA\n");
break;
case OCI_ERROR:
(void) OCIErrorGet((dvoid *)errhp, (ub4) 1, (text *) NULL, &errcode,
errbuf, (ub4) sizeof(errbuf), OCI_HTYPE_ERROR);
(void) printf("Error - %.*s\n", 512, errbuf);
break;
case OCI_INVALID_HANDLE:
(void) printf("Error - OCI_INVALID_HANDLE\n");
break;
case OCI_STILL_EXECUTING:
(void) printf("Error - OCI_STILL_EXECUTE\n");
break;
case OCI_CONTINUE:
(void) printf("Error - OCI_CONTINUE\n");
break;
default:
break;
}
}

12.5 OCI and Application Continuity
Application Continuity (AC) gives High Availability (HA) during planned and unplanned
outages. OCI support for AC was introduced with Oracle Database 12c Release 2
(12.2).
AC masks hardware, software, network, storage errors, and timeouts in a HA
environment running either Oracle RAC, Oracle RAC One, or Active Data Guard for
instance or site failover. AC provides support for SQL*Plus, Tuxedo, WebLogic Server,
and JDBC Type 4 (Oracle Thin), OCI, and Oracle Data Provider for .NET (ODP.NET)
drivers.
With planned outages for applications that use the OCI session pool, the OCI session
pool detects when a connection has been affected by a PLANNED DOWN event and
terminates the connection when it is returned to the pool. In planned outages for
applications that do not use the OCI session pool, an OCI application detects when a
connection has been impacted by a planned shutdown event. In either case, OCI
implicitly determines when DML replay is safe and applications see fewer errors
following a shutdown event.

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OCI and Application Continuity

With unplanned outages, OCI uses Transaction Guard, which enables an OCI
application to reliably determine the outcome of a transaction by recovering an in-flight
transaction after a recoverable error occurs. This support means the completion of
application requests during outages incurs only a minor delay while restoring database
connectivity and session state. AC only attempts to replay an in-flight transaction if it
can determine the transaction did not commit during original execution.
For AC support for OCI, Oracle recommends you use an OCI session pool or Tuxedo.
This section includes the following topics:
•

About Added Support for Application Continuity

•

What Happens Following a Recoverable Error

•

Criteria for Successful Replay

•

What Factors Disable Application Continuity in OCI

•

Failed Replay

•

When Is Application Continuity Most Effective

See Also:
•

Oracle Real Application Clusters Administration and Deployment Guide
for information about creating services for Application Continuity and
Transaction Guard.

12.5.1 About Added Support for Application Continuity
Oracle Database release 18c, version 18.1 adds more support for Application
Continuity.
Beginning with Oracle Database release 18c, version 18.1, the following support is
added for Application Continuity:
•

Support is added for OCI dynamic binds and defines for numeric, character, and
date/time types. This means the following OCI APIs are extended to support
Application Continuity: OCIBindDynamic() and OCIDefineDynamic().

•

Support is added for binding and defining objects. This means the following OCI
APIs are extended to support Application Continuity: OCIBindObject(),
OCIDefineObject(), and OCITypeByName().

•

During execution of LOB calls, Application Continuity now supports the handling of
connection failure by restarting LOB calls that were interrupted by an outage.

•

OCI now supports the new Application Continuity FAILOVER_TYPE of AUTO, which only
attempts to fail over if the session state is known to be restorable at the explicit
request boundary.

12.5.2 What Happens Following a Recoverable Error
Following a recoverable error, database sessions fail over from one database instance
to another database instance.

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OCI and Application Continuity

The new instance may be part of the same Oracle RAC cluster, or an Oracle Data
Guard standby database that has been brought up as a primary database following a
site failure. After transparent application failover (TAF) successfully reconnects and
reauthenticates, Application Continuity in OCI replays the call history associated with
the failed session, including all SQL and PL/SQL statements. Replay operates on a
single session and does not attempt to synchronize the re-submission activity with any
other database session. Replay is successful only if the client-visible results of
transaction replay are identical to the original submission.

12.5.3 Criteria for Successful Replay
Successful driver replay requires that the client-visible effects of a post-failover
transaction be identical to the initial submission.
This success is indicated by the following criteria:
•

Return codes and error message text must be identical.

•

Result sets must be identical. The define data must be identical and the rows must
be returned in the same order.

•

The rows processed count must be identical. For example, a post-failover update
statement must update the same number of rows as the original update statement.

•

Session state for the new connection matches session state from the original
connection.

See Oracle Real Application Clusters Administration and Deployment Guide for
information about these criteria.
Stability of Mutable Data and Application Continuity
When values change from one execution to the next for a mutable object, its data is
considered to be mutable and is thus guaranteed to be non-replayable. Sequences are
an example of this mutable data.
To improve the success rate for DML replay, it is necessary to replay DML involving
mutable data with the values used at initial submission. If the original values are not
kept and if different values for these mutable objects are returned to the client, replay
is rejected because the client sees different results.
Support for keeping mutable object values is currently provided for SYSDATE,
SYSTIMESTAMP, SYS_GUID, and sequence.NEXTVAL.

See Also:
Oracle Real Application Clusters Administration and Deployment Guide for
more information about mutable objects and Application Continuity.

12.5.4 What Factors Disable Application Continuity in OCI
Lists the factors that implicitly disables Application Continuity in OCI until the start of
the next application request.

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The following situations implicitly disables Application Continuity in OCI until the start
of the next application request:
•

The server detects a condition that is not consistent with replay. For example, for
SESSION_STATE_CONSISTENCY=DYNAMIC if a PL/SQL anonymous block has an
embedded top level COMMIT statement (autonomous transactions are not
considered top level), the driver implicitly disables Application Continuity in OCI.

•

The application calls an OCI function that is not supported by Application
Continuity in OCI.

The application can explicitly disable Application Continuity in OCI by calling
OCIRequestDisableReplay().

12.5.5 Failed Replay
What causes replay to fail.
When Application Continuity in OCI replays a transaction, the following situations will
cause replay to fail:
•

Encountering a COMMIT statement at replay time

•

Replay results are not consistent with the initial submission of the transaction

•

Presence of a recoverable error during replay if the internal replay retries limit is
exceeded

•

Applications that use OCIStmtPrepare() return the following error: Error ORA-25412: transaction replay disabled by call to OCIStmtPrepare. Use the
OCIStmtPrepare2() call to support the use of Application Continuity in an HA
infrastructure.

Application Continuity returns an error if it cannot successfully replay a failed
transaction. Additional diagnostic information will be logged in the client-side trace file
to indicate the reason for the replay failure.

12.5.6 When Is Application Continuity Most Effective
What determines the effectiveness of Application Continuity in OCI.
Application Continuity in OCI is most effective under the following conditions:
•

The database service specifies the COMMIT_OUTCOME attribute and transparent
application failover (TAF) is configured.

•

An application is able to mark the beginning and end of an application request,
either explicitly (calling OCIRequestBegin() and OCIRequestEnd()) or implicitly through
use of an OCI session pool.

•

An application request contains at most one database transaction that is
committed at the end of the request.

•

If the application executes PL/SQL or Java in the server, that PL/SQL or Java:

•

–

Does not have embedded COMMIT statements

–

Does not set any state (for example, package variables) that is expected to
persist after the PL/SQL or Java completes.

The TAF callback does not leave an open database transaction.

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This section includes the following topics:
•

When Application Continuity in OCI Can Fail Over

•

Application Continuity in OCI Does Not Support These Constructs

•

Possible Side Effects of Application Continuity

12.5.6.1 When Application Continuity in OCI Can Fail Over
Describes with which functions when Application Continuity in OCI can fail over if an
outage occurs.
Application Continuity in OCI can fail over if an outage occurs during one of the
following functions:
•

OCILobAppend()

•

OCILobArrayRead()

•

OCILobArrayWrite()

•

OCILobAssign()

•

OCILobCharSetForm()

•

OCILobClose()

•

OCILobCopy2()

•

OCILobCreateTemporary()

•

OCILobDisableBuffering()

•

OCILobEnableBuffering()

•

OCILobFileClose()

•

OCILobFileCloseAll()

•

OCILobFileGetName()

•

OCILobFileIsOpen()

•

OCILobFileOpen()

•

OCILobFileSetName()

•

OCILobFlushBuffer()

•

OCILobFreeTemporary()

•

OCILobGetChunkSize()

•

OCILobGetLength()

•

OCILobGetLength2()

•

OCILobGetStorageLimit()

•

OCILobIsEqual()

•

OCILobIsOpen()

•

OCILobIsTemporary()

•

OCILobLoadFromFile()

•

OCILobLoadFromFile2()

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•

OCILobLocatorAssign()

•

OCILobLocatorIsInit()

•

OCILobOpen()

•

OCILobRead()

•

OCILobRead2()

•

OCILobTrim()

•

OCILobTrim2()

•

OCILobWriteAppend()

•

OCILobWriteAppend2()

•

OCILobWrite()

•

OCILobWrite2()

•

OCIPing()

•

OCIStmtExecute()

•

OCIStmtFetch()

•

OCIStmtFetch2()

•

OCISessionEnd()

•

OCITransCommit()

•

OCITransRollback()

12.5.6.2 Application Continuity in OCI Does Not Support These Constructs
What constructs are not supported by Application Continuity in OCI.
Application Continuity in OCI does not support the following constructs:
•

XA Transactions

•

PL/SQL blocks with embedded COMMIT statements

•

AQ Dequeue in dequeue immediate mode (deqopt.visibility)

•

Streaming binds or defines of descriptor-based types such as objects or lob
locators

•

Function OCIStmtPrepare()

•

Registered OCI callbacks of type OCI_CBTYPE_ENTRY that do not return OCI_CONTINUE

•

COMMIT NOWAIT statement

•

DCL commands

12.5.6.3 Possible Side Effects of Application Continuity
Application Continuity in OCI replays the original PL/SQL and SQL statements
following a recoverable error once a session is rebuilt and the database state is
restored. The replay leaves side-effects that are seen twice, which may or may not be
desirable.

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It is important that applications understand these side-effects and decide whether
duplicate execution is acceptable. If it is not acceptable, then the application must take
action to accommodate or mitigate the effects of replay. For example, by calling
OCIRequestDisableReplay().

See Also:
Oracle Real Application Clusters Administration and Deployment Guide for
more information about examples of actions that create side effects.

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13
Notification Methods and Streams
Advanced Queuing
This chapter describes continuous query notification, publish-subscribe notification,
and Streams advanced queuing features.
This chapter includes the following topics:
•

About Continuous Query Notification

•

Publish-Subscribe Notification in OCI

•

OCI and Streams Advanced Queuing

13.1 About Continuous Query Notification
Continuous Query Notification (CQN) enables client applications to register queries
with the database and receive notifications in response to DML or DDL changes on the
objects or in response to result set changes associated with the queries.
The notifications are published by the database when the DML or DDL transaction
commits.
During registration, the application specifies a notification handler and associates a set
of interesting queries with the notification handler. A notification handler can be either
a server-side PL/SQL procedure or a client-side C callback. Registrations are created
at either the object level or the query level. If registration is at the object level, then
whenever a transaction changes any of the registered objects and commits, the
notification handler is invoked. If registration is at the query level, then whenever a
transaction commits changes such that the result set of the query is modified, the
notification handler is invoked, but if the changes do not affect the result set of the
query, the notification handler is not invoked.
Query change notification can be registered for the following types of statements:
OCI_STMT_SELECT, OCI_STMT_BEGIN, OCI_STMT_DECLARE, and OCI_STMT_CALL.
Query change notification assumes that the PLSQL code performs only SELECT
statements and registers for every SELECT statement. Otherwise, it raises an error if
there are any non SELECT statements in the PLSQL code.
One use of continuous query notification is in middle-tier applications that must have
cached data and keep the cache as recent as possible for the back-end database.
The notification includes the following information:
•

Query IDs of queries whose result sets have changed. This is if the registration
was at query granularity.

•

Names of the modified objects or changed rows.

•

Operation type (INSERT, UPDATE, DELETE, ALTER TABLE, DROP TABLE).

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•

ROWIDs of the changed rows and the associated DML operation (INSERT, UPDATE,
DELETE).

•

Global database events (STARTUP, SHUTDOWN). In Oracle Real Application Cluster
(Oracle RAC) the database delivers a notification when the first instance starts or
the last instance shuts down.

See Also:
•

Oracle Database Development Guide, the section about using
continuous query notification for a complete discussion of the concepts
of this feature and using OCI and PL/SQL interfaces to create CQN
registrations

•

Publish-Subscribe Notification in OCI

13.2 Publish-Subscribe Notification in OCI
The publish-subscribe notification feature allows an OCI application to receive client
notifications directly, register an email address to which notifications can be sent,
register an HTTP URL to which notifications can be posted, or register a PL/SQL
procedure to be invoked on a notification.
Figure 13-1 illustrates the process.

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Figure 13-1

Publish-Subscribe Model

Trigger
Mechanism

E-mail Client

Nonpersistent
Queues
OCI Client
System
Events
push

push
Persistent
Transactional
Queues

HTTP Server

Database
PL/SQL
procedure

Clients
Client

Supplier

Channel

Consumer

An OCI application can:
•

Register interest in notifications in the AQ namespace and be notified when an
enqueue occurs

•

Register interest in subscriptions to database events and receive notifications
when the events are triggered

•

Manage registrations, such as disabling registrations temporarily or dropping the
registrations entirely

•

Post or send notifications to registered clients

In all the preceding scenarios the notification can be received directly by the OCI
application, or the notification can be sent to a prespecified email address, or it can be
sent to a predefined HTTP URL, or a prespecified database PL/SQL procedure can be
invoked because of a notification.
Registered clients are notified asynchronously when events are triggered or on an
explicit AQ enqueue. Clients do not need to be connected to a database.
This section includes the following topics:
•

Publish-Subscribe Registration Functions in OCI

•

Notification Callback in OCI

•

Notification Procedure

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•

Publish-Subscribe Direct Registration Example

•

Publish-Subscribe LDAP Registration Example

See Also:
•

OCI and Streams Advanced Queuing for information about Streams
Advanced Queuing

•

Oracle Database Advanced Queuing User's Guide for information about
creating queues and about Streams AQ, including concepts, features,
and examples

•

The chapter about CREATE TRIGGER in the Oracle Database SQL Language
Reference for information about creating triggers

13.2.1 Publish-Subscribe Registration Functions in OCI
You can register directly to the database or register using Lightweight Directory
Access Protocol (LDAP).
Registration can be done in two ways:
•

Direct registration. You register directly to the database. This way is simple and
the registration takes effect immediately.

•

Open registration. You register using Lightweight Directory Access Protocol
(LDAP), from which the database receives the registration request. This is useful
when the client cannot have a database connection (the client wants to register for
a database open event while the database is down), or if the client wants to
register for the same event or events in multiple databases simultaneously.

This section includes the following topics:
•

Publish-Subscribe Register Directly to the Database

•

Open Registration for Publish-Subscribe

•

Using OCI to Open Register with LDAP

•

Setting QOS, Timeout Interval, Namespace, Client Address, and Port Number

•

OCI Functions Used to Manage Publish-Subscribe Notification

See Also:
•

Publish-Subscribe Register Directly to the Database

•

Open Registration for Publish-Subscribe

13.2.1.1 Publish-Subscribe Register Directly to the Database
The following steps are required in an OCI application to register directly and receive
notifications for events.

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It is assumed that the appropriate event trigger or AQ queue has been set up. The
initialization parameter COMPATIBLE must be set to 8.1 or later.

See Also:
•

Streams Advanced Queuing and Publish-Subscribe Functions

•

Publish-Subscribe Direct Registration Example for examples of the use
of these functions in an application

Note:
The publish-subscribe feature is only available on multithreaded operating
systems.

1.

Call OCIEnvCreate() or OCIEnvNlsCreate() with OCI_EVENTS mode to specify that the
application is interested in registering for and receiving notifications. This starts a
dedicated listening thread for notifications on the client.

2.

Call OCIHandleAlloc() with handle type OCI_HTYPE_SUBSCRIPTION to allocate a
subscription handle.

3.

Call OCIAttrSet() to set the subscription handle attributes for:
•

OCI_ATTR_SUBSCR_NAME - Subscription name

•

OCI_ATTR_SUBSCR_NAMESPACE - Subscription namespace

•

OCI_ATTR_SUBSCR_HOSTADDR - Environment handle attribute that sets the client IP

(in either IPv4 or IPv6 format) to which notification is sent
Oracle Database components and utilities support Internet Protocol version 6
(IPv6) addresses.

See Also:
OCI_ATTR_SUBSCR_HOSTADDR,
OCI_ATTR_SUBSCR_IPADDR, and Oracle Database Net Services
Administrator's Guide for more information about the IPv6 format for
IP addresses
•

OCI_ATTR_SUBSCR_CALLBACK - Notification callback

•

OCI_ATTR_SUBSCR_CTX - Callback context

•

OCI_ATTR_SUBSCR_PAYLOAD - Payload buffer for posting

•

OCI_ATTR_SUBSCR_RECPT - Recipient name

•

OCI_ATTR_SUBSCR_RECPTPROTO - Protocol to receive notification with

•

OCI_ATTR_SUBSCR_RECPTPRES - Presentation to receive notification with

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•

OCI_ATTR_SUBSCR_QOSFLAGS - QOS (quality of service) levels with the following

values:

•

–

If OCI_SUBSCR_QOS_PURGE_ON_NTFN is set, the registration is purged on the first
notification.

–

If OCI_SUBSCR_QOS_RELIABLE is set, notifications are persistent. You can use
surviving instances of an Oracle RAC database to send and retrieve
change notification messages even after a node failure, because
invalidations associated with this registration are queued persistently into
the database. If FALSE, then invalidations are enqueued into a fast inmemory queue. Note that this option describes the persistence of
notifications and not the persistence of registrations. Registrations are
automatically persistent by default.

OCI_ATTR_SUBSCR_TIMEOUT - Registration timeout interval in seconds. The default

is 0 if a timeout is not set.
•

OCI_ATTR_SUBSCR_NTFN_GROUPING_CLASS - notification grouping class

Notifications can be spaced out by using the grouping NTFN option with the
following constants. A value supported for notification grouping class is:
#define OCI_SUBSCR_NTFN_GROUPING_CLASS_TIME

1 /* time */

•

OCI_ATTR_SUBSCR_NTFN_GROUPING_VALUE - notification grouping value in seconds

•

OCI_ATTR_SUBSCR_NTFN_GROUPING_TYPE - notification grouping type

Supported values for notification grouping type:
#define OCI_SUBSCR_NTFN_GROUPING_TYPE_SUMMARY 1 /* summary */
#define OCI_SUBSCR_NTFN_GROUPING_TYPE_LAST
2 /* last */

•

OCI_ATTR_SUBSCR_NTFN_GROUPING_START_TIME - notification grouping start time

•

OCI_ATTR_SUBSCR_NTFN_GROUPING_REPEAT_COUNT - notification grouping repeat

count
OCI_ATTR_SUBSCR_NAME, OCI_ATTR_SUBSCR_NAMESPACE, and OCI_ATTR_SUBSCR_RECPTPROTO
must be set before you register a subscription.

If OCI_ATTR_SUBSCR_RECPTPROTO is set to OCI_SUBSCR_PROTO_OCI, then
OCI_ATTR_SUBSCR_CALLBACK and OCI_ATTR_SUBSCR_CTX also must be set.
If OCI_ATTR_SUBSCR_RECPTPROTO is set to OCI_SUBSCR_PROTO_MAIL,
OCI_SUBSCR_PROTO_SERVER, or OCI_SUBSCR_PROTO_HTTP, then OCI_ATTR_SUBSCR_RECPT
also must be set.
Setting OCI_ATTR_SUBSCR_CALLBACK and OCI_ATTR_SUBSCR_RECPT at the same time
causes an application error.
OCI_ATTR_SUBSCR_PAYLOAD is required before the application can perform a post to a

subscription.

See Also:
Subscription Handle Attributes and About Creating the OCI Environment
for setting up the environment with mode = OCI_EVENTS | OCI_OBJECT.
OCI_OBJECT is required for grouping notifications.
4.

Set he values of QOS, timeout interval, namespace, and port (see Example 9–15).

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See Also:
Setting QOS, Timeout Interval, Namespace, Client Address, and Port
Number
5.

Set OCI_ATTR_SUBSCR_RECPTPROTO to OCI_SUBSCR_PROTO_OCI, then define the callback
routine to be used with the subscription handle.

See Also:
Notification Callback in OCI
6.

Set OCI_ATTR_SUBSCR_RECPTPROTO to OCI_SUBSCR_PROTO_SERVER, then define the
PL/SQL procedure, to be invoked on notification, in the database.

See Also:
Notification Procedure
7.

Call OCISubscriptionRegister() to register with the subscriptions. This call can
register interest in several subscriptions at the same time.

Example 13-1 shows an example of setting QOS levels.
Example 13-1 Setting QOS Levels, the Notification Grouping Class, Value, and
Type, and the Namespace Specific Context
/* Set QOS levels */
ub4 qosflags = OCI_SUBSCR_QOS_PAYLOAD;
/* Set QOS flags in subscription handle */
(void) OCIAttrSet((dvoid *) subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(dvoid *) &qosflags, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_QOSFLAGS, errhp);
/* Set notification grouping class */
ub4 ntfn_grouping_class = OCI_SUBSCR_NTFN_GROUPING_CLASS_TIME;
(void) OCIAttrSet((dvoid *) subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(dvoid *) &ntfn_grouping_class, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_NTFN_GROUPING_CLASS, errhp);
/* Set notification grouping value of 10 minutes */
ub4 ntfn_grouping_value = 600;
(void) OCIAttrSet((dvoid *) subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(dvoid *) &ntfn_grouping_value, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_NTFN_GROUPING_VALUE, errhp);
/* Set notification grouping type */
ub4 ntfn_grouping_type = OCI_SUBSCR_NTFN_GROUPING_TYPE_SUMMARY;
/* Set notification grouping type in subscription handle */
(void) OCIAttrSet((dvoid *) subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(dvoid *) &ntfn_grouping_type, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_NTFN_GROUPING_TYPE, errhp);

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/* Set namespace specific context */
(void) OCIAttrSet((dvoid *) subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(dvoid *) NULL, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_NAMESPACE_CTX, errhp);

See Also:
•

OCIEnvCreate()

•

OCIEnvNlsCreate()

•

OCIHandleAlloc()

•

OCIAttrSet()

•

OCISubscriptionRegister()

13.2.1.2 Open Registration for Publish-Subscribe
Lists the prerequisites for the open registration for publish-subscribe.
Prerequisites for the open registration for publish-subscribe are as follows:
•

Registering using LDAP (open registration) requires the client to be an enterprise
user.

See Also:
Oracle Database Enterprise User Security Administrator's Guide,
sections about managing enterprise user security
•

The compatibility of the database must be 9.0 or later.

•

LDAP_REGISTRATION_ENABLED must be set to TRUE. This can be done this way:
ALTER SYSTEM SET LDAP_REGISTRATION_ENABLED=TRUE

The default is FALSE.
•

LDAP_REG_SYNC_INTERVAL must be set to the time interval (in seconds) to refresh

registrations from LDAP:
ALTER SYSTEM SET LDAP_REG_SYNC_INTERVAL = time_interval

The default is 0, which means do not refresh.
•

To force a database refresh of LDAP registration information immediately:
ALTER SYSTEM REFRESH LDAP_REGISTRATION

The steps for open registration using Oracle Enterprise Security Manager (OESM) are:
1.

In each enterprise domain, create the enterprise role, ENTERPRISE_AQ_USER_ROLE.

2.

For each database in the enterprise domain, add the global role
GLOBAL_AQ_USER_ROLE to the enterprise role ENTERPRISE_AQ_USER_ROLE.

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3.

For each enterprise domain, add the enterprise role ENTERPRISE_AQ_USER_ROLE to the
privilege group cn=OracleDBAQUsers, under cn=oraclecontext, under the
administrative context.

4.

For each enterprise user that is authorized to register for events in the database,
grant the enterprise role ENTERPRISE_AQ_USER_ROLE.

13.2.1.3 Using OCI to Open Register with LDAP
Shows how to open register using LDAP registration.
1.

Call OCIEnvCreate() or OCIEnvNlsCreate() with mode set to OCI_EVENTS | OCI_USE_LDAP.

2.

Call OCIAttrSet() to set the following environment handle attributes for accessing
LDAP:
•

OCI_ATTR_LDAP_HOST: the host name on which the LDAP server resides

•

OCI_ATTR_LDAP_PORT: the port on which the LDAP server is listening

•

OCI_ATTR_BIND_DN: the distinguished name to log in to the LDAP server, usually

the DN of the enterprise user
•

OCI_ATTR_LDAP_CRED: the credential used to authenticate the client, for example,

the password for simple authentication (user name and password)
•

OCI_ATTR_WALL_LOC: for SSL authentication, the location of the client wallet

•

OCI_ATTR_LDAP_AUTH: the authentication method code

See Also:
Environment Handle Attributes for a complete list of authentication
modes
•

OCI_ATTR_LDAP_CTX: the administrative context for Oracle Database in the LDAP

server
3.

Call OCIHandleAlloc() with handle type OCI_HTYPE_SUBSCRIPTION, to allocate a
subscription handle.

4.

Call OCIArrayDescriptorAlloc() with descriptor type OCI_DTYPE_SRVDN, to allocate a
server DN descriptor.

5.

Call OCIAttrSet()to set the server DN descriptor attributes for OCI_ATTR_SERVER_DN,
the distinguished name of the database in which the client wants to receive
notifications. OCIAttrSet() can be called multiple times for this attribute so that
more than one database server is included in the registration.

6.

Call OCIAttrSet() to set the subscription handle attributes for:
•

OCI_ATTR_SUBSCR_NAME - Subscription name

•

OCI_ATTR_SUBSCR_NAMESPACE - Subscription namespace

•

OCI_ATTR_SUBSCR_CALLBACK- Notification callback

•

OCI_ATTR_SUBSCR_CTX - Callback context

•

OCI_ATTR_SUBSCR_PAYLOAD - Payload buffer for posting

•

OCI_ATTR_SUBSCR_RECPT - Recipient name

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•

OCI_ATTR_SUBSCR_RECPTPROTO - Protocol to receive notification with

•

OCI_ATTR_SUBSCR_RECPTRES - Presentation to receive notification with

•

OCI_ATTR_SUBSCR_QOSFLAGS - QOS (quality of service) levels

•

OCI_ATTR_SUBSCR_TIMEOUT - Registration timeout interval in seconds. The default

is 0 if a timeout is not set.
•

OCI_ATTR_SUBSCR_SERVER_DN - The descriptor handles you populated in Step 5

7.

The values of QOS, timeout interval, namespace, and port are set. See Setting
QOS, Timeout Interval, Namespace, Client Address, and Port Number.

8.

Call OCISubscriptionRegister() to register the subscriptions. The registration takes
effect when the database accesses LDAP to pick up new registrations. The
frequency of pickups is determined by the value of LDAP_REG_SYNC_INTERVAL.

See Also:
•

OCIEnvCreate()

•

OCIEnvNlsCreate()

•

OCIAttrSet()

•

OCIHandleAlloc()

•

OCIArrayDescriptorAlloc()

•

OCISubscriptionRegister()

13.2.1.4 Setting QOS, Timeout Interval, Namespace, Client Address, and Port
Number
Shows how to set QOSFLAGS to QOS levels using OCIAttrSet().
You can set QOSFLAGS to the following QOS levels using OCIAttrSet():
•

OCI_SUBSCR_QOS_RELIABLE - Reliable notification persists across instance and

database restarts. Reliability is of the server only and is only for persistent queues
or buffered messages. This option describes the persistence of the notifications.
Registrations are persistent by default.
•

OCI_SUBSCR_QOS_PURGE_ON_NTFN - Once notification is received, purge registration on

first notification. (Subscription is unregistered.)
/* Set QOS levels */
ub4 qosflags = OCI_SUBSCR_QOS_RELIABLE | OCI_SUBSCR_QOS_PURGE_ON_NTFN;
/* Set flags in subscription handle */
(void)OCIAttrSet((void *)subscrhp, (ub4)OCI_HTYPE_SUBSCRIPTION,
(void *)&qosflags, (ub4)0, (ub4)OCI_ATTR_SUBSCR_QOSFLAGS, errhp);
/* Set auto-expiration after 30 seconds */
ub4 timeout = 30;
(void)OCIAttrSet((void *)subscrhp, (ub4)OCI_HTYPE_SUBSCRIPTION,
(void *)&timeout, (ub4)0, (ub4)OCI_ATTR_SUBSCR_TIMEOUT, errhp);

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The registration is purged when the timeout is exceeded, and a notification is sent to
the client, so that the client can invoke its callback and take any necessary action. For
client failure before the timeout, the registration is purged.
You can set the port number on the environment handle, which is important if the client
is on a system behind a firewall that can receive notifications only on certain ports.
Clients can specify the port for the listener thread before the first registration, using an
attribute in the environment handle. The thread is started the first time
OCISubscriptionRegister() is called. If available, this specified port number is used. An
error is returned if the client tries to start another thread on a different port using a
different environment handle.
ub4 port = 1581;
(void)OCIAttrSet((void *)envhp, (ub4)OCI_HTYPE_ENV, (void *)&port, (ub4)0,
(ub4)OCI_ATTR_SUBSCR_PORTNO, errhp);

If instead, the port is determined automatically, you can get the port number at which
the client thread is listening for notification by obtaining the attribute from the
environment handle.
(void)OCIAttrGet((void *)subhp, (ub4)OCI_HTYPE_ENV, (void *)&port, (ub4)0,
(ub4)OCI_ATTR_SUBSCR_PORTNO, errhp);

Example to set client address:
text ipaddr[16] = "10.177.246.40";
(void)(OCIAttrSet((dvoid *) envhp, (ub4) OCI_HTYPE_ENV,
(dvoid *) ipaddr, (ub4) strlen((const char *)ipaddr),
(ub4) OCI_ATTR_SUBSCR_IPADDR, errhp));

See Also:
OCI_ATTR_SUBSCR_IPADDR

13.2.1.5 OCI Functions Used to Manage Publish-Subscribe Notification
Lists and describes the functions used to manage publish-subscribe notification.
Table 13-1 lists the functions that are used to manage publish-subscribe notification.
Table 13-1

Publish-Subscribe Functions

Function

Purpose

OCISubscriptionDisable()

Disables a subscription

OCISubscriptionEnable()

Enables a subscription

OCISubscriptionPost()

Posts a subscription

OCISubscriptionRegister()

Registers a subscription

OCISubscriptionUnRegister()

Unregisters a subscription

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13.2.2 Notification Callback in OCI
The client must register a notification callback that gets invoked when there is some
activity on the subscription for which interest has been registered.
In the AQ namespace, for instance, this occurs when a message of interest is
enqueued.
This callback is typically set through the OCI_ATTR_SUBSCR_CALLBACK attribute of the
subscription handle.

See Also:
Subscription Handle Attributes

The callback must return a value of OCI_CONTINUE and adhere to the following
specification:
typedef ub4 (*OCISubscriptionNotify) ( void
OCISubscription
void
ub4
void
ub4

*pCtx,
*pSubscrHp,
*pPayload,
iPayloadLen,
*pDescriptor,
iMode);

The parameters are described as follows:
pCtx (IN)
A user-defined context specified when the callback was registered.
pSubscrHp (IN)
The subscription handle specified when the callback was registered.
pPayload (IN)
The payload for this notification. Currently, only ub1 * (a sequence of bytes) for the
payload is supported.
iPayloadLen (IN)
The length of the payload for this notification.
pDescriptor (IN)
The namespace-specific descriptor. Namespace-specific parameters can be extracted
from this descriptor. The structure of this descriptor is opaque to the user and its type
is dependent on the namespace.
The attributes of the descriptor are namespace-specific. For Advanced Queuing (AQ),
the descriptor is OCI_DTYPE_AQNFY. For the AQ namespace, the count of notifications
received in the group is provided in the notification descriptor. The attributes of
pDescriptor are:
•

Notification flag (regular = 0, timeout = 1, or grouping notification = 2) OCI_ATTR_NFY_FLAGS

•

Queue name - OCI_ATTR_QUEUE_NAME

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•

Consumer name - OCI_ATTR_CONSUMER_NAME

•

Message ID - OCI_ATTR_NFY_MSGID

•

Message properties - OCI_ATTR_MSG_PROP

•

Count of notifications received in the group - OCI_ATTR_AQ_NTFN_GROUPING_COUNT

•

The group, an OCI collection - OCI_ATTR_AQ_NTFN_GROUPING_MSGID_ARRAY

See Also:
•

OCI and Streams Advanced Queuing

•

Notification Descriptor Attributes

iMode (IN)
Call-specific mode. The only valid value is OCI_DEFAULT. This value executes the
default call.
Example 13-2 shows how to use AQ grouping notification attributes in a notification
callback.
Example 13-2
Callback

Using AQ Grouping Notification Attributes in an OCI Notification

ub4 notifyCB1(void
void
{
oratext
ub4
OCIColl
ub4
OCIRaw
void
sb4
void
boolean
ub2
oratext
ub4

*ctx, OCISubscription *subscrhp, void *pay, ub4 payl,
*desc, ub4 mode)
*subname;
size;
*msgid_array = (OCIColl *)0;
msgid_cnt = 0;
*msgid;
**msgid_ptr;
num_msgid = 0;
*elemind = (void *)0;
exist;
flags;
*hexit = (oratext *)"0123456789ABCDEF";
i, j;

/* get subscription name */
OCIAttrGet(subscrhp, OCI_HTYPE_SUBSCRIPTION, (void *)&subname, &size,
OCI_ATTR_SUBSCR_NAME,ctxptr->errhp);
/* print subscripton name */
printf("Got notification for %.*s\n", size, subname);
fflush((FILE *)stdout);
/* get the #ntfns received in this group */
OCIAttrGet(desc, OCI_DTYPE_AQNFY, (void *)&msgid_cnt, &size,
OCI_ATTR_AQ_NTFN_GROUPING_COUNT, ctxptr->errhp);
/* get the group - collection of msgids */
OCIAttrGet(desc, OCI_DTYPE_AQNFY, (void *)&msgid_array, &size,
OCI_ATTR_AQ_NTFN_GROUPING_MSGID_ARRAY, ctxptr->errhp);
/* get notification flag - regular, timeout, or grouping notification? */

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OCIAttrGet(desc, OCI_DTYPE_AQNFY, (void *)&flags, &size,
OCI_ATTR_NFY_FLAGS, ctxptr->errhp);
/* print notification flag */
printf("Flag: %d\n", (int)flags);
/* get group (collection) size */
if (msgid_array)
checkerr(ctxptr->errhp,
OCICollSize(ctxptr->envhp, ctxptr->errhp,
CONST OCIColl *) msgid_array, &num_msgid),
"Inside notifyCB1-OCICollSize");
else
num_msgid =0;
/* print group size */
printf("Collection size: %d\n", num_msgid);
/* print all msgids in the group */
for(i = 0; i < num_msgid; i++)
{
ub4 rawSize;
ub1 *rawPtr;
/* get msgid from group */
checkerr(ctxptr->errhp,
OCICollGetElem(ctxptr->envhp, ctxptr->errhp,
(OCIColl *) msgid_array, i, &exist,
(void **)(&msgid_ptr), &elemind),
"Inside notifyCB1-OCICollGetElem");
msgid = *msgid_ptr;
rawSize = OCIRawSize(ctxptr->envhp, msgid);
rawPtr = OCIRawPtr(ctxptr->envhp, msgid);

/* raw size
*/
/* raw pointer */

/* print msgid size */
printf("Msgid size: %d\n", rawSize);
/* print msgid in hexadecimal format */
for (j = 0; j < rawSize; j++)
{
/* for each byte in the raw */
printf("%c", hexit[(rawPtr[j] & 0xf0) >> 4]);
printf("%c", hexit[(rawPtr[j] & 0x0f)]);
}
printf("\n");
}
/* print #ntfns received in group */
printf("Notification Count: %d\n", msgid_cnt);
printf("\n");
printf("***********************************************************\n");
fflush((FILE *)stdout);
return 1;
}

13.2.3 Notification Procedure
The PL/SQL notification procedure that is invoked when there is some activity on the
subscription for which interest has been registered, must be created in the database.
This procedure is typically set through the OCI_ATTR_SUBSCR_RECPT attribute of the
subscription handle.

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See Also:
•

Subscription Handle Attributes

•

"Oracle Streams AQ PL/SQL Callback" in Oracle Database PL/SQL
Packages and Types Reference for the PL/SQL procedure specification

13.2.4 Publish-Subscribe Direct Registration Example
Shows examples implementing publish subscription notification using direct
registration.
Example 13-3 shows how system events, client notification, and Advanced Queuing
work together to implement publish subscription notification.
The PL/SQL code in Example 13-3 creates all objects necessary to support a publishsubscribe mechanism under the user schema pubsub. In this code, the Agent snoop
subscribes to messages that are published at logon events. Note that the user pubsub
needs AQ_ADMINISTRATOR_ROLE and AQ_USER_ROLE privileges to use Advance Queuing
functionality. The initialization parameter _SYSTEM_TRIG_ENABLED must be set to TRUE (the
default) to enable triggers for system events. Connect as pubsub before running
Example 13-3.
After the subscriptions are created, the client must register for notification using
callback functions. Example 13-4 shows sample code that performs the necessary
steps for registration. The initial steps of allocating and initializing session handles are
omitted here for clarity.
If user IX logs on to the database, the client is notified by email, and the callback
function notifySnoop is called. An email notification is sent to the address
xyz@company.com and the PL/SQL procedure plsqlnotifySnoop is also called in the
database.
Example 13-3

Implementing a Publish Subscription Notification

-------------------------------------------------------------create queue table for persistent multiple consumers
------------------------------------------------------------- Create or replace a queue table
begin
DBMS_AQADM.CREATE_QUEUE_TABLE(
QUEUE_TABLE=>'pubsub.raw_msg_table',
MULTIPLE_CONSUMERS => TRUE,
QUEUE_PAYLOAD_TYPE =>'RAW',
COMPATIBLE => '8.1.5');
end;
/
------------------------------------------------------------- Create a persistent queue for publishing messages
------------------------------------------------------------- Create a queue for logon events
begin
DBMS_AQADM.CREATE_QUEUE(QUEUE_NAME=>'pubsub.logon',
QUEUE_TABLE=>'pubsub.raw_msg_table',
COMMENT=>'Q for error triggers');
end;

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/
------------------------------------------------------------- Start the queue
---------------------------------------------------------begin
DBMS_AQADM.START_QUEUE('pubsub.logon');
end;
/
------------------------------------------------------------- define new_enqueue for convenience
---------------------------------------------------------create or replace procedure new_enqueue(queue_name in varchar2,
payload in raw ,
correlation in varchar2 := NULL,
exception_queue in varchar2 := NULL)
as
enq_ct
dbms_aq.enqueue_options_t;
msg_prop dbms_aq.message_properties_t;
enq_msgid raw(16);
userdata raw(1000);
begin
msg_prop.exception_queue := exception_queue;
msg_prop.correlation := correlation;
userdata := payload;
DBMS_AQ.ENQUEUE(queue_name,enq_ct, msg_prop,userdata,enq_msgid);
end;
/
------------------------------------------------------------- add subscriber with rule based on current user name,
---- using correlation_id
---------------------------------------------------------declare
subscriber sys.aq$_agent;
begin
subscriber := sys.aq$_agent('SNOOP', null, null);
dbms_aqadm.add_subscriber(queue_name => 'pubsub.logon',
subscriber => subscriber,
rule => 'CORRID = ''ix'' ');
end;
/
------------------------------------------------------------- create a trigger on logon on database
------------------------------------------------------------- create trigger on after logon
create or replace trigger systrig2
AFTER LOGON
ON DATABASE
begin
new_enqueue('pubsub.logon', hextoraw('9999'), dbms_standard.login_user);
end;
/
------------------------------------------------------------- create a PL/SQL callback for notification of logon
---- of user 'ix' on database
------------------------------------------------------------create or replace procedure plsqlnotifySnoop(
context raw, reginfo sys.aq$_reg_info, descr sys.aq$_descriptor,
payload raw, payloadl number)
as

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begin
dbms_output.put_line('Notification : User ix Logged on\n');
end;
/

Example 13-4

Registering for Notification Using Callback Functions

...
static ub4 namespace = OCI_SUBSCR_NAMESPACE_AQ;
static OCISubscription *subscrhpSnoop = (OCISubscription *)0;
static OCISubscription *subscrhpSnoopMail = (OCISubscription *)0;
static OCISubscription *subscrhpSnoopServer = (OCISubscription *)0;
/* callback function for notification of logon of user 'ix' on database */
static ub4 notifySnoop(ctx, subscrhp, pay, payl, desc, mode)
void *ctx;
OCISubscription *subscrhp;
void *pay;
ub4 payl;
void *desc;
ub4 mode;
{
printf("Notification : User ix Logged on\n");
(void)OCIHandleFree((void *)subscrhpSnoop,
(ub4) OCI_HTYPE_SUBSCRIPTION);
return 1;
}
static void checkerr(errhp, status)
OCIError *errhp;
sword status;
{
text errbuf[512];
ub4 buflen;
sb4 errcode;
if (status == OCI_SUCCESS) return;
switch (status)
{
case OCI_SUCCESS_WITH_INFO:
printf("Error - OCI_SUCCESS_WITH_INFO\n");
break;
case OCI_NEED_DATA:
printf("Error - OCI_NEED_DATA\n");
break;
case OCI_NO_DATA:
printf("Error - OCI_NO_DATA\n");
break;
case OCI_ERROR:
OCIErrorGet ((void *) errhp, (ub4) 1, (text *) NULL, &errcode,
errbuf, (ub4) sizeof(errbuf), (ub4) OCI_HTYPE_ERROR);
printf("Error - %s\n", errbuf);
break;
case OCI_INVALID_HANDLE:
printf("Error - OCI_INVALID_HANDLE\n");
break;
case OCI_STILL_EXECUTING:
printf("Error - OCI_STILL_EXECUTING\n");

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break;
case OCI_CONTINUE:
printf("Error - OCI_CONTINUE\n");
break;
default:
printf("Error - %d\n", status);
break;
}
}
static void initSubscriptionHn (subscrhp,
subscriptionName,
func,
recpproto,
recpaddr,
recppres)
OCISubscription **subscrhp;
char * subscriptionName;
void * func;
ub4 recpproto;
char * recpaddr;
ub4 recppres;
{
/* allocate subscription handle */
(void) OCIHandleAlloc((void *) envhp, (void **)subscrhp,
(ub4) OCI_HTYPE_SUBSCRIPTION,
(size_t) 0, (void **) 0);
/* set subscription name in handle */
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) subscriptionName,
(ub4) strlen((char *)subscriptionName),
(ub4) OCI_ATTR_SUBSCR_NAME, errhp);
/* set callback function in handle */
if (func)
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) func, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_CALLBACK, errhp);
/* set context in handle */
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) 0, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_CTX, errhp);
/* set namespace in handle */
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) &namespace, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_NAMESPACE, errhp);
/* set receive with protocol in handle */
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) &recpproto, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_RECPTPROTO, errhp);
/* set recipient address in handle */
if (recpaddr)
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) recpaddr, (ub4) strlen(recpaddr),
(ub4) OCI_ATTR_SUBSCR_RECPT, errhp);

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/* set receive with presentation in handle */
(void) OCIAttrSet((void *) *subscrhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) &recppres, (ub4) 0,
(ub4) OCI_ATTR_SUBSCR_RECPTPRES, errhp);
printf("Begining Registration for subscription %s\n", subscriptionName);
checkerr(errhp, OCISubscriptionRegister(svchp, subscrhp, 1, errhp,
OCI_DEFAULT));
printf("done\n");
}

int main( argc, argv)
int
argc;
char * argv[];
{
OCISession *authp = (OCISession *) 0;
/*****************************************************
Initialize OCI Process/Environment
Initialize Server Contexts
Connect to Server
Set Service Context
******************************************************/
/* Registration Code Begins */
/* Each call to initSubscriptionHn allocates
and initializes a Registration Handle */
/* Register for OCI notification */
initSubscriptionHn(
&subscrhpSnoop,
/* subscription handle*/
(char*) "PUBSUB.LOGON:SNOOP", /* subscription name */
/*: */
(void*)notifySnoop, /* callback function */
OCI_SUBSCR_PROTO_OCI, /* receive with protocol */
(char *)0, /* recipient address */
OCI_SUBSCR_PRES_DEFAULT); /* receive with presentation */
/* Register for email notification */
initSubscriptionHn(
&subscrhpSnoopMail, /* subscription handle */
(char*) "PUBSUB.LOGON:SNOOP",
/* subscription name */
/* : */
(void*)0, /* callback function */
OCI_SUBSCR_PROTO_MAIL, /* receive with protocol */
(char*) "xyz@company.com", /* recipient address */
OCI_SUBSCR_PRES_DEFAULT); /* receive with presentation */
/* Register for server to server notification */
initSubscriptionHn(
&subscrhpSnoopServer, /* subscription handle */
(char*) "PUBSUB.LOGON:SNOOP",
/* subscription name */
/* : */
(void*)0, /* callback function */
OCI_SUBSCR_PROTO_SERVER, /* receive with protocol */
(char*) "pubsub.plsqlnotifySnoop", /* recipient address */
OCI_SUBSCR_PRES_DEFAULT); /* receive with presentation */
checkerr(errhp, OCITransCommit(svchp, errhp, (ub4) OCI_DEFAULT));
/*****************************************************
The Client Process does not need a live Session for Callbacks.

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End Session and Detach from Server.
******************************************************/
OCISessionEnd ( svchp, errhp, authp, (ub4) OCI_DEFAULT);
/* detach from server */
OCIServerDetach( srvhp, errhp, OCI_DEFAULT);
while (1)
sleep(1);

/* wait for callback */

}

13.2.5 Publish-Subscribe LDAP Registration Example
Shows an example that illustrates how to do LDAP registration.
Example 13-5 shows a code fragment that illustrates how to do LDAP registration.
Please read all the program comments.
Example 13-5

LDAP Registration

...
/* To use the LDAP registration feature, OCI_EVENTS | OCI_EVENTS |OCI_USE_LDAP*/
/* must be set in OCIEnvCreate or OCIEnvNlsCreate */
/*
(Note: OCIInitialize is deprecated): */
(void) OCIInitialize((ub4) OCI_EVENTS|OCI_OBJECT|OCI_USE_LDAP, (void *)0,
(void * (*)(void *, size_t)) 0,
(void * (*)(void *, void *, size_t))0,
(void (*)(void *, void *)) 0 );
...
/* set LDAP attributes in the environment handle */
/* LDAP host name */
(void) OCIAttrSet((void *)envhp, OCI_HTYPE_ENV, (void *)"yow", 3,
OCI_ATTR_LDAP_HOST, (OCIError *)errhp);
/* LDAP server port */
ldap_port = 389;
(void) OCIAttrSet((void *)envhp, OCI_HTYPE_ENV, (void *)&ldap_port,
(ub4)0, OCI_ATTR_LDAP_PORT, (OCIError *)errhp);
/* bind DN of the client, normally the enterprise user name */
(void) OCIAttrSet((void *)envhp, OCI_HTYPE_ENV, (void *)"cn=orcladmin",
12, OCI_ATTR_BIND_DN, (OCIError *)errhp);
/* password of the client */
(void) OCIAttrSet((void *)envhp, OCI_HTYPE_ENV, (void *)"welcome",
7, OCI_ATTR_LDAP_CRED, (OCIError *)errhp);
/* authentication method is "simple", username/password authentication */
ldap_auth = 0x01;
(void) OCIAttrSet((void *)envhp, OCI_HTYPE_ENV, (void *)&ldap_auth,
(ub4)0, OCI_ATTR_LDAP_AUTH, (OCIError *)errhp);
/* administrative context: this is the DN above cn=oraclecontext */
(void) OCIAttrSet((void *)envhp, OCI_HTYPE_ENV, (void *)"cn=acme,cn=com",
14, OCI_ATTR_LDAP_CTX, (OCIError *)errhp);

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...
/* retrieve the LDAP attributes from the environment handle */
/* LDAP host */
(void) OCIAttrGet((void *)envhp, OCI_HTYPE_ENV, (void *)&buf,
&szp, OCI_ATTR_LDAP_HOST, (OCIError *)errhp);
/* LDAP server port */
(void) OCIAttrGet((void *)envhp, OCI_HTYPE_ENV, (void *)&intval,
0, OCI_ATTR_LDAP_PORT, (OCIError *)errhp);
/* client binding DN */
(void) OCIAttrGet((void *)envhp, OCI_HTYPE_ENV, (void *)&buf,
&szp, OCI_ATTR_BIND_DN, (OCIError *)errhp);
/* client password */
(void) OCIAttrGet((void *)envhp, OCI_HTYPE_ENV, (void *)&buf,
&szp, OCI_ATTR_LDAP_CRED, (OCIError *)errhp);
/* administrative context */
(void) OCIAttrGet((void *)envhp, OCI_HTYPE_ENV, (void *)&buf,
&szp, OCI_ATTR_LDAP_CTX, (OCIError *)errhp);
/* client authentication method */
(void) OCIAttrGet((void *)envhp, OCI_HTYPE_ENV, (void *)&intval,
0, OCI_ATTR_LDAP_AUTH, (OCIError *)errhp);
...
/* to set up the server DN descriptor in the subscription handle */
/* allocate a server DN descriptor, dn is of type "OCIServerDNs **",
subhp is of type "OCISubscription **" */
(void) OCIDescriptorAlloc((void *)envhp, (void **)dn,
(ub4) OCI_DTYPE_SRVDN, (size_t)0, (void **)0);
/* now *dn is the server DN descriptor, add the DN of the first database
that you want to register */
(void) OCIAttrSet((void *)*dn, (ub4) OCI_DTYPE_SRVDN,
(void *)"cn=server1,cn=oraclecontext,cn=acme,cn=com",
42, (ub4)OCI_ATTR_SERVER_DN, errhp);
/* add the DN of another database in the descriptor */
(void) OCIAttrSet((void *)*dn, (ub4) OCI_DTYPE_SRVDN,
(void *)"cn=server2,cn=oraclecontext,cn=acme,cn=com",
42, (ub4)OCI_ATTR_SERVER_DN, errhp);
/* set the server DN descriptor into the subscription handle */
(void) OCIAttrSet((void *) *subhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *) *dn, (ub4)0, (ub4) OCI_ATTR_SERVER_DNS, errhp);
...
/* now you will try to get the server DN information from the subscription
handle */
/* first, get the server DN descriptor out */
(void) OCIAttrGet((void *) *subhp, (ub4) OCI_HTYPE_SUBSCRIPTION,
(void *)dn, &szp, OCI_ATTR_SERVER_DNS, errhp);
/* then, get the number of server DNs in the descriptor */

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(void) OCIAttrGet((void *) *dn, (ub4)OCI_DTYPE_SRVDN, (void *)&intval,
&szp, (ub4)OCI_ATTR_DN_COUNT, errhp);
/* allocate an array of char * to hold server DN pointers returned by
an Oracle database*/
if (intval)
{
arr = (char **)malloc(intval*sizeof(char *));
(void) OCIAttrGet((void *)*dn, (ub4)OCI_DTYPE_SRVDN, (void *)arr,
&intval, (ub4)OCI_ATTR_SERVER_DN, errhp);
}
/* OCISubscriptionRegister() calls have two modes: OCI_DEFAULT and
OCI_REG_LDAPONLY. If OCI_DEFAULT is used, there should be only one
server DN in the server DN descriptor. The registration request will
be sent to the database. If a database connection is not available,
the registration request will be detoured to the LDAP server. However,
if mode OCI_REG_LDAPONLY is used, the registration request
will be directly sent to LDAP. This mode should be used when there is
more than one server DN in the server DN descriptor or you are sure
that a database connection is not available.
In this example, two DNs are entered, so you should use mode
OCI_REG_LDAPONLY in LDAP registration. */
OCISubscriptionRegister(svchp, subhp, 1, errhp, OCI_REG_LDAPONLY);
...
/* as OCISubscriptionRegister(), OCISubscriptionUnregister() also has
mode OCI_DEFAULT and OCI_REG_LDAPONLY. The usage is the same. */
OCISubscriptionUnRegister(svchp, *subhp, errhp, OCI_REG_LDAPONLY);
}
...

13.3 OCI and Streams Advanced Queuing
OCI provides an interface to the Streams Advanced Queuing (Streams AQ) feature.
Streams AQ provides message queuing as an integrated part of Oracle Database.
Streams AQ provides this functionality by integrating the queuing system with the
database, thereby creating a message-enabled database. By providing an integrated
solution, Streams AQ frees application developers to devote their efforts to their
specific business logic rather than having to construct a messaging infrastructure.

Note:
To use Streams Advanced Queuing, you must be using the Enterprise
Edition of Oracle Database.

This section includes the following topics:
•

OCI Streams Advanced Queuing Functions

•

OCI Streams Advanced Queuing Descriptors

•

Streams Advanced Queuing in OCI Versus PL/SQL

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OCI and Streams Advanced Queuing

•

Using Buffered Messaging

See Also:
•

Oracle Database Advanced Queuing User's Guide

•

Oracle XML Developer's Kit Programmer's Guide

•

The description of OCIAQEnq() for example code demonstrating the use
of OCI with AQ

13.3.1 OCI Streams Advanced Queuing Functions
Lists the OCI Streams Advanced Queuing functions.
The OCI library includes several functions related to Streams Advanced Queuing:
•

OCIAQEnq()

•

OCIAQDeq()

•

OCIAQListen() (Deprecated)

•

OCIAQListen2()

•

OCIAQEnqArray()

•

OCIAQDeqArray()

You can enqueue an array of messages to a single queue. The messages all share
the same enqueue options, but each message in the array can have different message
properties. You can also dequeue an array of messages from a single queue. For
transaction group queues, you can dequeue all messages for a single transaction
group using one call.

See Also:
•

Streams Advanced Queuing and Publish-Subscribe Functions

•

OCIAQEnq()

•

OCIAQDeq()

•

OCIAQListen()

•

OCIAQListen2()

•

OCIAQEnqArray()

•

OCIAQDeqArray()

13.3.2 OCI Streams Advanced Queuing Descriptors
Lists the OCI Streams Advanced Queuing descriptors and shows their usage.

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The following descriptors are used by OCI Streams AQ operations:
•

OCIAQEnqOptions

•

OCIAQDeqOptions

•

OCIAQMsgProperties

•

OCIAQAgent

You can allocate these descriptors with the service handle using the standard
OCIDescriptorAlloc() call. The following code shows examples of this:
OCIDescriptorAlloc(svch,
OCIDescriptorAlloc(svch,
OCIDescriptorAlloc(svch,
OCIDescriptorAlloc(svch,

&enqueue_options, OCI_DTYPE_AQENQ_OPTIONS, 0, 0 );
&dequeue_options, OCI_DTYPE_AQDEQ_OPTIONS, 0, 0 );
&message_properties, OCI_DTYPE_AQMSG_PROPERTIES, 0, 0);
&agent, OCI_DTYPE_AQAGENT, 0, 0 );

Each descriptor has a variety of attributes that can be set or read.

See Also:
•

Streams Advanced Queuing Descriptor Attributes

•

OCIDescriptorAlloc()

13.3.3 Streams Advanced Queuing in OCI Versus PL/SQL
Shows a comparison between functions, parameters, and options for OCI Streams AQ
functions and descriptors, and PL/SQL AQ functions in the DBMS_AQ package.
The following tables compare functions, parameters, and options for OCI Streams AQ
functions and descriptors, and PL/SQL AQ functions in the DBMS_AQ package.
Table 13-2 compares AQ functions.
Table 13-2

AQ Functions

PL/SQL Function

OCI Function

DBMS_AQ.ENQUEUE

OCIAQEnq()

DBMS_AQ.DEQUEUE

OCIAQDeq()

DBMS_AQ.LISTEN

OCIAQListen(), OCIAQListen2()

DBMS_AQ.ENQUEUE_ARRAY

OCIAQEnqArray()

DBMS_AQ.DEQUEUE_ARRAY

OCIAQDeqArray()

Table 13-3 compares the parameters for the enqueue functions.
Table 13-3

Enqueue Parameters

DBMS_AQ.ENQUEUE Parameter

OCIAQEnq() Parameter

queue_name

queue_name

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Table 13-3

(Cont.) Enqueue Parameters

DBMS_AQ.ENQUEUE Parameter

OCIAQEnq() Parameter

enqueue_options

enqueue_options

message_properties

message_properties

payload

payload

msgid

msgid

-

Note: OCIAQEnq() requires the following additional
parameters: svch, errh, payload_tdo, payload_ind,
and flags.

Table 13-4 compares the parameters for the dequeue functions.
Table 13-4

Dequeue Parameters

DBMS_AQ.DEQUEUE Parameter

OCIAQDeq() Parameter

queue_name

queue_name

dequeue_options

dequeue_options

message_properties

message_properties

payload

payload

msgid

msgid

-

Note: OCIAQDeq() requires the following additional
parameters: svch, errh, dequeue_options,
message_properties, payload_tdo, payload,
payload_ind, and flags.

Table 13-5 compares parameters for the listen functions.
Table 13-5

Listen Parameters

DBMS_AQ.LISTEN Parameter

OCIAQListen2() Parameter

agent_list

agent_list

wait

wait

agent

agent

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Table 13-5

(Cont.) Listen Parameters

DBMS_AQ.LISTEN Parameter
listen_delivery_mode
-

OCIAQListen2() Parameter
lopts
Note: OCIAQListen2() requires the following additional
parameters: svchp, errhp, agent_list, num_agents,
agent, lmops, and flags.

Table 13-6 compares parameters for the array enqueue functions.
Table 13-6

Array Enqueue Parameters

DBMS_AQ.ENQUEUE_ARRAY
Parameter

OCIAQEnqArray() Parameter

queue_name

queue_name

enqueue_options

enqopt

array_size

iters

message_properties_array

msgprop

payload_array

payload

msgid_array

msgid

-

Note: OCIAQEnqArray() requires the following
additional parameters: svch, errh,
payload_tdo, payload_ind, ctxp, enqcbfp,
and flags.

Table 13-7 compares parameters for the array dequeue functions.
Table 13-7

Array Dequeue Parameters

DBMS_AQ.DEQUEUE_ARRAY
Parameter

OCIAQDeqArray() Parameter

queue_name

queue_name

dequeue_options

deqopt

array_size

iters

message_properties_array

msgprop

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Table 13-7

(Cont.) Array Dequeue Parameters

DBMS_AQ.DEQUEUE_ARRAY
Parameter

OCIAQDeqArray() Parameter

payload_array

payload

msgid_array

msgid

-

Note: OCIAQDeqArray() requires the following
additional parameters: svch, errh, msgprop,
payload_tdo, payload_ind, ctxp, deqcbfp,
and flags.

Table 13-8 compares parameters for the agent attributes.
Table 13-8

Agent Parameters

PL/SQL Agent Parameter

OCIAQAgent Attribute
OCI_ATTR_AGENT_NAME

name

OCI_ATTR_AGENT_ADDRESS

address

OCI_ATTR_AGENT_PROTOCOL

protocol

Table 13-9 compares parameters for the message properties.
Table 13-9

Message Properties

PL/SQL Message Property
priority
delay
expiration
correlation
attempts
recipient_list
exception_queue
enqueue_time

OCIAQMsgProperties Attribute
OCI_ATTR_PRIORITY
OCI_ATTR_DELAY
OCI_ATTR_EXPIRATION
OCI_ATTR_CORRELATION
OCI_ATTR_ATTEMPTS
OCI_ATTR_RECIPIENT_LIST
OCI_ATTR_EXCEPTION_QUEUE
OCI_ATTR_ENQ_TIME

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Table 13-9

(Cont.) Message Properties

PL/SQL Message Property

OCIAQMsgProperties Attribute
OCI_ATTR_MSG_STATE

state

OCI_ATTR_SENDER_ID

sender_id
transaction_group
original_msgid

OCI_ATTR_TRANSACTION_NO
OCI_ATTR_ORIGINAL_MSGID
OCI_ATTR_MSG_DELIVERY_MODE

delivery_mode

Table 13-10 compares enqueue option attributes.
Table 13-10

Enqueue Option Attributes

PL/SQL Enqueue Option

OCIAQEnqOptions Attribute
OCI_ATTR_VISIBILITY

visibility
relative_msgid
sequence_deviation
transformation

OCI_ATTR_RELATIVE_MSGID
OCI_ATTR_SEQUENCE_DEVIATION
(deprecated)
OCI_ATTR_TRANSFORMATION
OCI_ATTR_MSG_DELIVERY_MODE

delivery_mode

Table 13-11 compares dequeue option attributes.
Table 13-11

Dequeue Option Attributes

PL/SQL Dequeue Option
consumer_name
dequeue_mode
navigation
visibility
wait

OCIAQDeqOptions Attribute
OCI_ATTR_CONSUMER_NAME
OCI_ATTR_DEQ_MODE
OCI_ATTR_NAVIGATION
OCI_ATTR_VISIBILITY
OCI_ATTR_WAIT

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Table 13-11

(Cont.) Dequeue Option Attributes

PL/SQL Dequeue Option

OCIAQDeqOptions Attribute
OCI_ATTR_DEQ_MSGID

msgid
correlation

OCI_ATTR_CORRELATION

deq_condition

OCI_ATTR_DEQCOND

transformation

OCI_ATTR_TRANSFORMATION

delivery_mode

OCI_ATTR_MSG_DELIVERY_MODE

Note:
OCIAQEnq() returns the error ORA-25219 while specifying the enqueue option
OCI_ATTR_SEQUENCE along with OCI_ATTR_RELATIVE_MSGID. This happens when

enqueuing two messages. For the second message, enqueue options
OCI_ATTR_SEQUENCE and OCI_ATTR_RELATIVE_MSGID are set to dequeue this

message before the first one. An error is not returned if you do not specify
the sequence but, of course, the message is not dequeued before the
relative message.
OCIAQEnq() does not return an error if the OCI_ATTR_SEQUENCE attribute is not

set, but the message is not dequeued before the message with relative
message ID.

See Also:
OCIAQEnq()

13.3.4 Using Buffered Messaging
Buffered messaging is a nonpersistent messaging capability within Streams AQ that
was first available in Oracle Database 10g Release 2.
Buffered messages reside in shared memory and can be lost if there is an instance
failure. Unlike persistent messages, redo does not get written to disk. Buffered
message enqueue and dequeue is much faster than persistent message operations.
Because shared memory is limited, buffered messages may have to be spilled to disk.
Flow control can be enabled to prevent applications from flooding the shared memory
when the message consumers are slow or have stopped for some reason. The
following functions are used for buffered messaging:
•

OCIAQEnq()

•

OCIAQDeq()

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•

OCIAQListen2()

Example 13-6 shows an example of enqueue buffered messaging.
Example 13-7 shows an example of dequeue buffered messaging.

Note:
Array operations are not supported for buffered messaging. Applications can
use the OCIAQEnqArray() and OCIAQDeqArray() functions with the array size set
to 1.

Example 13-6

Enqueue Buffered Messaging

...
OCIAQMsgProperties *msgprop;
OCIAQEnqueueOptions *enqopt;
message
msg;
/* message is an object type */
null_message
nmsg; /* message indicator */
...
/* Allocate descriptors */
OCIDescriptorAlloc(envhp, (void **)&enqopt, OCI_DTYPE_AQENQ_OPTIONS, 0,
(void **)0));
OCIDescriptorAlloc(envhp, (void **)&msgprop,OCI_DTYPE_AQMSG_PROPERTIES, 0,
(void **)0));
/* Set delivery mode to buffered */
dlvm = OCI_MSG_BUFFERED;
OCIAttrSet(enqopt, OCI_DTYPE_AQENQ_OPTIONS, (void *)&dlvm, sizeof(ub2),
OCI_ATTR_MSG_DELIVERY_MODE, errhp);
/* Set visibility to Immediate (visibility must always be immediate for buffered
messages) */
vis = OCI_ENQ_ON_COMMIT;
OCIAttrSet(enqopt, OCI_DTYPE_AQENQ_OPTIONS,(void *)&vis, sizeof(ub4),
OCI_ATTR_VISIBILITY, errhp)
/* Message was an object type created earlier, msg_tdo is its type
descriptor object */
OCIAQEnq(svchp, errhp, "Test_Queue", enqopt, msgprop, msg_tdo, (void **)&mesg,
(void **)&nmesg, (OCIRaw **)0, 0));
...

Example 13-7

Dequeue Buffered Messaging

...
OCIAQMsgProperties *msgprop;
OCIAQDequeueOptions *deqopt;
...
OCIDescriptorAlloc(envhp, (void **)&mprop, OCI_DTYPE_AQMSG_PROPERTIES, 0,
(void **)0));
OCIDescriptorAlloc(envhp, (void **)&deqopt, OCI_DTYPE_AQDEQ_OPTIONS, 0,
(void **)0);
/* Set visibility to Immediate (visibility must always be immediate for buffered
message operations) */
vis = OCI_ENQ_ON_COMMIT;

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OCIAttrSet(deqopt, OCI_DTYPE_AQDEQ_OPTIONS,(void *)&vis, sizeof(ub4),
OCI_ATTR_VISIBILITY, errhp)
/* delivery mode is buffered */
dlvm = OCI_MSG_BUFFERED;
OCIAttrSet(deqopt, OCI_DTYPE_AQDEQ_OPTIONS, (void *)&dlvm, sizeof(ub2),
OCI_ATTR_MSG_DELIVERY_MODE, errhp);
/* Set the consumer for which to dequeue the message (this must be specified
regardless of the type of message being dequeued).
*/
consumer = "FIRST_SUBSCRIBER";
OCIAttrSet(deqopt, OCI_DTYPE_AQDEQ_OPTIONS, (void *)consumer,
(ub4)strlen((char*)consumer), OCI_ATTR_CONSUMER_NAME, errhp);
/* Dequeue the message but do not return the payload (to simplify the code
fragment)
*/
OCIAQDeq(svchp, errhp, "test_queue", deqopt, msgprop, msg_tdo, (void **)0,
(void **)0, (OCIRaw**)0, 0);
...

See Also:
•

OCIAQEnq()

•

OCIAQDeq()

•

OCIAQListen2()

13-31

14
User-Defined Callback Functions in OCI
Oracle Call Interface can execute user-specific code in addition to OCI calls.
You can use this functionality for:
•

Adding tracing and performance measurement code to enable users to tune their
applications

•

Performing preprocessing or postprocessing code for specific OCI calls

•

Accessing other data sources with OCI by using the native OCI interface for
Oracle Databases and directing the OCI calls to use user callbacks for non-Oracle
data sources

The OCI callback feature provides support for calling user code before or after
executing the OCI calls. It also allows the user-defined code to be executed instead of
executing the OCI code.
The user callback code can be registered dynamically without modifying the source
code of the application. The dynamic registration is implemented by loading up to five
user-created dynamically linked libraries after the initialization of the environment
handle during the OCIEnvCreate() call. These user-created libraries (such as dynamiclink libraries (DLLs) on Windows, or shared libraries on Solaris, register the user
callbacks for the selected OCI calls transparently to the application.
Sample Application
For a listing of the complete demonstration programs that illustrate the OCI user
callback feature, see Appendix B.
This section includes the following topics:
•

About Registering User Callbacks in OCI

•

OCI Callbacks from External Procedures

See Also:
OCIEnvCreate()

14.1 About Registering User Callbacks in OCI
An application can register user callback libraries with the OCIUserCallbackRegister()
function.
Callbacks are registered in the context of the environment handle. An application can
retrieve information about callbacks registered with a handle with the
OCIUserCallbackGet() function.

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A user-defined callback is a subroutine that is registered against an OCI call and an
environment handle. It can be specified to be either an entry callback, a replacement
callback, or an exit callback.
•

If it is an entry callback, it is called when the program enters the OCI function.

•

Replacement callbacks are executed after entry callbacks. If the replacement
callback returns a value of OCI_CONTINUE, then a subsequent replacement callback
or the normal OCI-specific code is executed. If a replacement callback returns
anything other than OCI_CONTINUE, then subsequent replacement callbacks and the
OCI code do not execute.

•

After a replacement callback returns something other than OCI_CONTINUE, or an OCI
function successfully executes, program control transfers to the exit callback (if
one is registered).

If a replacement or exit callback returns anything other than OCI_CONTINUE, then the
return code from the callback is returned from the associated OCI call.
A user callback can return OCI_INVALID_HANDLE when either an invalid handle or an
invalid context is passed to it.

Note:
If any callback returns anything other than OCI_CONTINUE, then that return
code is passed to the subsequent callbacks. If a replacement or exit callback
returns a return code other than OCI_CONTINUE, then the final (not
OCI_CONTINUE) return code is returned from the OCI call.

This section includes the following topics:
•

OCIUserCallbackRegister

•

User Callback Function

•

User Callback Control Flow

•

User Callback for OCIErrorGet()

•

Errors from Entry Callbacks

•

Dynamic Callback Registrations

•

About Loading Multiple Packages

•

Package Format

•

User Callback Chaining

•

About Accessing Other Data Sources Through OCI

•

Restrictions on Callback Functions

•

Example of OCI Callbacks

See Also:
OCIUserCallbackGet() and OCIUserCallbackRegister()

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14.1.1 OCIUserCallbackRegister
A user callback is registered using the OCIUserCallbackRegister() call.
Currently, OCIUserCallbackRegister() is only registered on the environment handle.
The user's callback function of typedef OCIUserCallback is registered along with its
context for the OCI call identified by the OCI function code, fcode. The type of the
callback, whether entry, replacement, or exit, is specified by the when parameter.
For example, the stmtprep_entry_dyncbk_fn entry callback function and its context
dynamic_context, are registered against the environment handle hndlp for the
OCIStmtPrepare2() call by calling the OCIUserCallbackRegister() function with the
following parameters.
OCIUserCallbackRegister( hndlp,
OCI_HTYPE_ENV,
errh,
stmtprep_entry_dyncbk_fn,
dynamic_context,
OCI_FNCODE_STMTPREPARE,
OCI_UCBTYPE_ENTRY
(OCIUcb*) NULL);

See Also:
•

OCIUserCallbackRegister()

•

OCIStmtPrepare2()

14.1.2 User Callback Function
Details about the user callback function.
The user callback function must use the following syntax:
typedef sword (*OCIUserCallback)
(void *ctxp,
/* context for the user callback*/
void *hndlp,
/* handle for the callback, env handle for now */
ub4 type,
/* type of handlp, OCI_HTYPE_ENV for this release */
ub4 fcode,
/* function code of the OCI call */
ub1 when,
/* type of the callback, entry or exit */
sword returnCode, /* OCI return code */
ub4 *errnop,
/* Oracle error number */
va_list arglist); /* parameters of the oci call */

In addition to the parameters described in the OCIUserCallbackRegister() call, the
callback is called with the return code, errnop, and all the parameters of the original
OCI as declared by the prototype definition.
The return code is always passed in as OCI_SUCCESS and *errnop is always passed in as
0 for the first entry callback. Note that *errnop refers to the content of errnop because
errnop is an IN/OUT parameter.

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If the callback does not want to change the OCI return code, then it must return
OCI_CONTINUE, and the value returned in *errnop is ignored. If, however, the callback
returns any return code other than OCI_CONTINUE, the last returned return code
becomes the return code for the call. At this point, the value returned for *errnop is set
in the error handle, or in the environment handle if the error information is returned in
the environment handle because of the absence of the error handle for certain OCI
calls such as OCIHandleAlloc().
For replacement callbacks, the returnCode is the non-OCI_CONTINUE return code from the
previous callback or OCI call, and *errnop is the value of the error number being
returned in the error handle. This allows the subsequent callback to change the return
code or error information if needed.
The processing of replacement callbacks is different in that if it returns anything other
than OCI_CONTINUE, then subsequent replacement callbacks and OCI code are
bypassed and processing jumps to the exit callbacks.
Note that if the replacement callbacks return OCI_CONTINUE to allow processing of OCI
code, then the return code from entry callbacks is ignored.
All the original parameters of the OCI call are passed to the callback as variable
parameters, and the callback must retrieve them using the va_arg macros. The
callback demonstration programs provide examples.
A null value can be registered to deregister a callback. That is, if the value of the
callback (OCIUserCallback()) is NULL in the OCIUserCallbackRegister() call, then the user
callback is deregistered.
When using the thread-safe mode, the OCI program acquires all mutexes before
calling the user callbacks.

See Also:
•

OCI Demonstration Programs

•

OCIUserCallbackRegister()

•

OCIHandleAlloc()

14.1.3 User Callback Control Flow
Shows the control flow for a user callback.
Example 14-1 shows pseudocode that describes the overall processing of a typical
OCI call.
Example 14-1
OCI Call

Pseudocode That Describes the Overall Processing of a Typical

OCIXyzCall()
{
Acquire mutexes on handles;
retCode = OCI_SUCCESS;
errno = 0;
for all ENTRY callbacks do
{

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About Registering User Callbacks in OCI

EntryretCode = (*entryCallback)(..., retcode, &errno, ...);
if (retCode != OCI_CONTINUE)
{
set errno in error handle or environment handle;
retCode = EntryretCode;
}
}
for all REPLACEMENT callbacks do
{
retCode = (*replacementCallback) (..., retcode, &errno, ...);
if (retCode != OCI_CONTINUE)
{
set errno in error handle or environment handle
goto executeEXITCallback;
}
}
retCode = return code for XyzCall; /* normal processing of OCI call */
errno = error number from error handle or env handle;
executeExitCallback:
for all EXIT callbacks do
{
exitRetCode = (*exitCallback)(..., retCode, &errno,...);
if (exitRetCode != OCI_CONTINUE)
{
set errno in error handle or environment handle;
retCode = exitRetCode;
}
}
release mutexes;
return retCode
}

14.1.4 User Callback for OCIErrorGet()
If the callbacks are a total replacement of the OCI code, then they usually maintain
their own error information in the call context and use that to return error information in
bufp and errcodep parameters of the replacement callback of the OCIErrorGet() call.
If, however, the callbacks are either partially overriding OCI code, or just doing some
other postprocessing, then they can use the exit callback to modify the error text and
errcodep parameters of the OCIErrorGet() call by their own error message and error
number. Note that the *errnop passed into the exit callback is the error number in the
error or the environment handle.

See Also:
OCIErrorGet()

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14.1.5 Errors from Entry Callbacks
If an entry callback wants to return an error to the caller of the OCI call, then it must
register a replacement or exit callback.
This is because if the OCI code is executed, then the error code from the entry
callback is ignored. Therefore, the entry callback must pass the error to the
replacement or exit callback through its own context.

14.1.6 Dynamic Callback Registrations
Because user callbacks are expected to be used for monitoring OCI behavior or to
access other data sources, it is desirable that the registration of the callbacks be done
transparently and nonintrusively.
This is accomplished by loading user-created dynamically linked libraries at OCI
initialization time. These dynamically linked libraries are called packages. The usercreated packages register the user callbacks for the selected OCI calls. These
callbacks can further register or deregister user callbacks as needed when receiving
control at runtime.
A makefile (ociucb.mk on Solaris) is provided with the OCI demonstration programs to
create the package. The exact naming and location of this package is operating
system-dependent. The source code for the package must provide code for special
callbacks that are called at OCI initialization and environment creation times.
Setting an operating system environment variable, ORA_OCI_UCBPKG, controls the loading
of the package. This variable names the packages in a generic way. The packages
must be located in the $ORACLE_HOME/lib directory.

14.1.7 About Loading Multiple Packages
The ORA_OCI_UCBPKG variable can contain a semicolon-separated list of package names.
The packages are loaded in the order they are specified in the list.
For example, in the past the package was specified as:
setenv ORA_OCI_UCBPKG mypkg

Currently, you can still specify the package as before, but in addition multiple
packages can be specified as:
setenv ORA_OCI_UCBPKG "mypkg;yourpkg;oraclepkg;sunpkg;msoftpkg"

All these packages are loaded in order. That is, mypkg is loaded first and msoftpkg is
loaded last.
A maximum of five packages can be specified.

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Note:
The sample makefile ociucb.mk creates ociucb.so.1.0 on a Solaris or
ociucb.dll on a Windows system. To load the ociucb package, the
environmental variable ORA_OCI_UCBPKG must be set to ociucb. On Solaris, if
the package name ends with .so, OCIEnvCreate() or OCIEnvNlsCreate()
fails. The package name must end with .so.1.0.
For further details about creating the dynamic-link libraries, read the
Makefiles provided in the demo directory for your operating system. For
further information about user-defined callbacks, see your operating systemspecific documentation on compiling and linking applications.

14.1.8 Package Format
The package source must provide two functions.
In the past, a package had to specify the source code for the OCIEnvCallback()
function. However, the OCIEnvCallback() function is obsolete. Instead, the package
source must provide two functions. The first function must be named as packagename
suffixed with the word Init. For example, if the package is named foo, then the source
file (for example, but not necessarily, foo.c) must contain a fooInit() function with a
call to OCISharedLibInit() function specified exactly as:
sword fooInit(metaCtx, libCtx, argfmt, argc, argv)
void *
metaCtx;
/* The metacontext */
void *
libCtx;
/* The context for this package. */
ub4
argfmt;
/* package argument format */
sword
argc;
/* package arg count*/
void *
argv[];
/* package arguments */
{
return (OCISharedLibInit(metaCtx, libCtx, argfmt, argc, argv,
fooEnvCallback));
}

The last parameter of the OCISharedLibInit() function, fooEnvCallback() in this case, is
the name of the second function. It can be named anything, but by convention it is
named packagename suffixed with the word EnvCallback.
This function is a replacement for OCIEnvCallback(). Currently, all the dynamic user
callbacks must be registered in this function. The function must be of type
OCIEnvCallbackType, which is specified as:
typedef sword (*OCIEnvCallbackType)(OCIEnv *env, ub4 mode,
size_t xtramem_sz, void *usrmemp,
OCIUcb *ucbDesc);

When an environment handle is created, then this callback function is called at the
very end. The env parameter is the newly created environment handle.
The mode, xtramem_sz, and usrmempp are the parameters passed to the OCIEnvCreate()
call. The last parameter, ucbDesc, is a descriptor that is passed to the package. The
package uses this descriptor to register the user callbacks as described later.
A sample ociucb.c file is provided in the demo directory. The makefile ociucb.mk is also
provided (on Solaris) in the demo directory to create the package. Please note that this

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may be different on other operating systems. The demo directory also contains full user
callback demo programs (cdemoucb.c, cdemoucbl.c) illustrating this.

14.1.9 User Callback Chaining
User callbacks can be registered statically in the application itself or dynamically at
runtime in the DLLs.
A mechanism is needed to allow the application to override a previously registered
callback and then later invoke the overridden one in the newly registered callback to
preserve the behavior intended by the dynamic registrations. This can result in
chaining of user callbacks.
The OCIUserCallbackGet() function determines which function and context is registered
for an OCI call.

See Also:
OCIUserCallbackGet()

14.1.10 About Accessing Other Data Sources Through OCI
Because Oracle Database is the predominant database software accessed,
applications can take advantage of the OCI interface to access non-Oracle data by
using the user callbacks to access them.
This allows an application written in OCI to access Oracle data without any
performance penalty. Drivers can be written that access the non-Oracle data in user
callbacks. Because OCI provides a very rich interface, there is usually a
straightforward mapping of OCI calls to most data sources. This solution is better than
writing applications for other middle layers such as ODBC that introduce performance
penalties for all data sources. Using OCI does not incur any penalty to access Oracle
data sources, and incurs the same penalty that ODBC does for non-Oracle data
sources.

14.1.11 Restrictions on Callback Functions
Details the restrictions on callback functions.
There are certain restrictions on the usage of callback functions, including
OCIEnvCallback():
•

A callback cannot call other OCI functions except OCIUserCallbackRegister(),
OCIUserCallbackGet(), OCIHandleAlloc(), and OCIHandleFree(). Even for these
functions, if they are called in a user callback, then callbacks on them are not
called to avoid recursion. For example, if OCIHandleFree() is called in the callback
for OCILogoff(), then the callback for OCIHandleFree() is disabled during the
execution of the callback for OCILogoff().

•

A callback cannot modify OCI data structures such as the environment or error
handles.

•

A callback cannot be registered for the OCIUserCallbackRegister() call itself, or for
any of the following calls:

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About Registering User Callbacks in OCI

–

OCIUserCallbackGet()

–

OCIEnvCreate()

–

OCIInitialize() (Deprecated)

–

OCIEnvNlsCreate()

See Also:
•

OCIUserCallbackRegister()

•

OCIUserCallbackGet()

•

OCIHandleAlloc()

•

OCIHandleFree()

•

OCILogoff()

•

OCIEnvCreate()

•

OCIInitialize()

•

OCIEnvNlsCreate()

14.1.12 Example of OCI Callbacks
Shows examples of using OCI callbacks.
Suppose that there are five packages each registering entry, replacement, and exit
callbacks for the OCIStmtPrepare2() call. That is, the ORA_OCI_UCBPKG variable is set as
shown in Example 14-2.
In each package pkgN (where N can be 1 through 5), the pkgNInit() and
PkgNEnvCallback() functions are specified, as shown in Example 14-3.
Example 14-4 shows how the pkgNEnvCallback() function registers the entry,
replacement, and exit callbacks.
Finally, Example 14-5 shows how in the source code for the application, user callbacks
can be registered with the NULL ucbDesc.
Example 14-6 shows that when the OCIStmtPrepare2() call is executed, the callbacks
are called in the following order.

Note:
The exit callbacks are called in the reverse order of the entry and
replacement callbacks.

The entry and exit callbacks can return any return code and the processing continues
to the next callback. However, if the replacement callback returns anything other than
OCI_CONTINUE, then the next callback (or OCI code if it is the last replacement callback)
in the chain is bypassed and processing jumps to the exit callback. For example, if

14-9

Chapter 14

About Registering User Callbacks in OCI

pkg3_replace_callback_fn() returned OCI_SUCCESS, then pkg4_replace_callback_fn(),
pkg5_replace_callback_fn(), and the OCI processing for the OCIStmtPrepare2() call are
bypassed. Instead, pkg5_exit_callback_fn() is executed next.

Example 14-2
Variable

Environment Variable Setting for the ORA_OCI_UCBPKG

setenv ORA_OCI_UCBPKG "pkg1;pkg2;pkg3;pkg4;pkg5"

Example 14-3

Specifying the pkgNInit() and PkgNEnvCallback() Functions

pkgNInit(void *metaCtx, void *libCtx, ub4 argfmt, sword argc, void **argv)
{
return OCISharedLibInit(metaCtx, libCtx, argfmt, argc, argv, pkgNEnvCallback);
}

Example 14-4 Using pkgNEnvCallback() to Register Entry, Replacement, and
Exit Callbacks
pkgNEnvCallback(OCIEnv *env, ub4 mode, size_t xtramemsz,
void *usrmemp, OCIUcb *ucbDesc)
{
OCIHandleAlloc((void *)env, (void **)&errh, OCI_HTYPE_ERROR, (size_t) 0,
(void **)NULL);
OCIUserCallbackRegister(env, OCI_HTYPE_ENV, errh, pkgN_entry_callback_fn,
pkgNctx, OCI_FNCODE_STMTPREPARE, OCI_UCBTYPE_ENTRY, ucbDesc);
OCIUserCallbackRegister(env, OCI_HTYPE_ENV, errh, pkgN_replace_callback_fn,
pkgNctx, OCI_FNCODE_STMTPREPARE, OCI_UCBTYPE_REPLACE, ucbDesc);
OCIUserCallbackRegister(env, OCI_HTYPE_ENV, errh, pkgN_exit_callback_fn,
pkgNctx, OCI_FNCODE_STMTPREPARE, OCI_UCBTYPE_EXIT, ucbDesc);
return OCI_CONTINUE;
}

Example 14-5

Registering User Callbacks with the NULL ucbDesc

OCIUserCallbackRegister(env, OCI_HTYPE_ENV, errh, static_entry_callback_fn,
pkgNctx, OCI_FNCODE_STMTPREPARE, OCI_UCBTYPE_ENTRY, (OCIUcb *)NULL);
OCIUserCallbackRegister(env, OCI_HTYPE_ENV, errh, static_replace_callback_fn,
pkgNctx, OCI_FNCODE_STMTPREPARE, OCI_UCBTYPE_REPLACE, (OCIUcb *)NULL);
OCIUserCallbackRegister(env, OCI_HTYPE_ENV, errh, static_exit_callback_fn,
pkgNctx, OCI_FNCODE_STMTPREPARE, OCI_UCBTYPE_EXIT, (OCIUcb *)NULL);

Example 14-6

Using the OCIStmtPrepare() Call to Call the Callbacks in Order

static_entry_callback_fn()
pkg1_entry_callback_fn()
pkg2_entry_callback_fn()
pkg3_entry_callback_fn()
pkg4_entry_callback_fn()
pkg5_entry_callback_fn()
static_replace_callback_fn()
pkg1_replace_callback_fn()
pkg2_replace_callback_fn()

14-10

Chapter 14

OCI Callbacks from External Procedures

pkg3_replace_callback_fn()
pkg4_replace_callback_fn()
pkg5_replace_callback_fn()
OCI code for OCIStmtPrepare call
pkg5_exit_callback_fn()
pkg4_exit_callback_fn()
pkg3_exit_callback_fn()
pkg2_exit_callback_fn()
pkg1_exit_callback_fn()
static_exit_callback_fn()

See Also:
OCIStmtPrepare2()

14.2 OCI Callbacks from External Procedures
Provides additional reference information about using OCI callbacks from external
procedures.
There are several OCI functions that you can use as callbacks from external
procedures.

See Also:
•

OCI Cartridge Functions for a list of functions you can use as callbacks
from external procedures

•

Oracle Database Development Guide for information about writing C
subroutines that can be called from PL/SQL code, including a list of
which OCI calls you can use and some example code

14-11

15
Performance Topics
This chapter describes topics about OCI performance features.
You can use OCI to access Oracle TimesTen In-Memory Database and Oracle
TimesTen Application-Tier Database Cache.
This chapter includes the following topics:
•

Statement Caching in OCI

•

Implicit Fetching of ROWIDs

•

OCI Support for Implicit Results

•

Client Result Cache

•

Client Statement Cache Auto-Tuning

See Also:
Oracle TimesTen In-Memory Database C Developers Guide for information
about Times Ten support for Oracle Call Interface.

15.1 Statement Caching in OCI
Statement caching refers to the feature that provides and manages a cache of
statements for each session.
In the server, it means that cursors are ready to be used without the need to parse the
statement again. You can use statement caching with connection pooling and with
session pooling, and improve performance and scalability. You can use it without
session pooling as well. OCI calls that implement statement caching are:
•

OCIStmtPrepare2()

•

OCIStmtRelease()

This section includes the following topics:
•

Statement Caching Without Session Pooling in OCI

•

Statement Caching with Session Pooling in OCI

•

Rules for Statement Caching in OCI

•

Bind and Define Optimization in Statement Caching

•

OCI Statement Caching Code Example

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Chapter 15

Statement Caching in OCI

See Also:
•

OCIStmtPrepare2()

•

OCIStmtRelease()

15.1.1 Statement Caching Without Session Pooling in OCI
To perform statement caching without session pooling, users perform the usual OCI
steps to log on.
The call to obtain a session has a mode that specifies whether statement caching is
enabled for the session. Initially the statement cache is empty. Developers try to find a
statement in the cache using the statement text. If the statement exists, the API
returns a previously prepared statement handle; otherwise, it returns a newly prepared
statement handle.
The application developer can perform binds and defines and then simply execute and
fetch the statement before returning the statement to the cache. If the statement
handle is not found in the cache, the developer must set different attributes on the
handle in addition to the other steps.
OCIStmtPrepare2() takes a mode that determines if the developer wants a prepared
statement handle or a null statement handle if the statement is not found in the cache.

The pseudocode looks like this:
OCISessionBegin( userhp, ... OCI_STMT_CACHE) ;
OCIAttrset(svchp, userhp, ...); /* Set the user handle in the service context */
OCIStmtPrepare2(svchp, &stmthp, stmttext, key, ...);
OCIBindByPos(stmthp, ...);
OCIDefineByPos(stmthp, ...);
OCIStmtExecute(svchp, stmthp, ...);
OCIStmtFetch2(svchp, ...);
OCIStmtRelease(stmthp, ...);
...

See Also:
OCIStmtPrepare2()

15.1.2 Statement Caching with Session Pooling in OCI
For statement caching with session pooling, the concepts remain the same, except
that the statement cache is enabled at the session pool layer rather than at the
session layer.
The attribute OCI_ATTR_SPOOL_STMTCACHESIZE sets the default statement cache size for
each of the sessions in the session pool. It is set on the OCI_HTYPE_SPOOL handle. The
statement cache size for a particular session in the pool can be overridden at any time
by using OCI_ATTR_STMTCACHESIZE on that session. The value of
OCI_ATTR_SPOOL_STMTCACHESIZE can be changed at any time. You can use this attribute

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Chapter 15

Statement Caching in OCI

to enable or disable statement caching at the pool level, after creation, just as attribute
OCI_ATTR_STMTCACHESIZE (on the service context) is used to enable or disable statement
caching at the session level. This change is reflected on individual sessions in the
pool, when they are provided to a user. Tagged sessions are an exception to this
behavior. This is explained later in this section.

Note:
You can change the attributes after acquiring a session. However, once an
attribute is changed, it will remain set on the underlying physical session.
This value will not be reset back implicitly while releasing the session back to
the session pool. Hence, it is the developer's responsibility to maintain the
state of the sessions before releasing the session using OCIStmtRelease().

Enabling or disabling of statement caching is allowed on individual pooled sessions as
it is on nonpooled sessions.
A user can enable statement caching on a session retrieved from a non-statement
cached pool in an OCISessionGet() or OCILogon2() call by specifying
OCI_SESSGET_STMTCACHE or OCI_LOGON2_STMTCACHE, respectively, in the mode argument.
When a user asks for a session from a session pool, the statement cache size for that
session defaults to that of the pool. This may also mean enabling or disabling
statement caching in that session. For example, if a pooled session (Session A) has
statement caching enabled, and statement caching is turned off in the pool, and a user
asks for a session, and Session A is returned, then statement caching is turned off in
Session A. As another example, if Session A in a pool does not have statement
caching enabled, and statement caching at the pool level is turned on, then before
returning Session A to a user, statement caching on Session A with size equal to that
of the pool is turned on.
This does not hold true if a tagged session is asked for and retrieved. In this case, the
size of the statement cache is not changed. Consequently, it is not turned on or off.
Moreover, if the user specifies mode OCI_SESSGET_STMTCACHE in the OCISessionGet() call,
this is ignored if the session is tagged. In our earlier example, if Session A was tagged,
then it is returned as is to the user.

See Also:
•

OCISessionGet()

•

OCILogon2()

15.1.3 Rules for Statement Caching in OCI
If you are using statement caching, follow these rules.
Here are some rules to follow for statement caching in OCI:
•

Use the function OCIStmtPrepare2() instead of OCIStmtPrepare(). If you are using
OCIStmtPrepare(), you are strongly urged not to use a statement handle across

15-3

Chapter 15

Statement Caching in OCI

different service contexts. Doing so raises an error if the statement has been
obtained by OCIStmtPrepare2(). Migration of a statement handle to a new service
context actually closes the cursor associated with the old session and therefore no
sharing is achieved. Client-side sharing is also not obtained, because OCI frees all
buffers associated with the old session when the statement handle is migrated.
•

You are required to keep one service context per session. Any statement handle
obtained using OCIStmtPrepare2() with a certain service context should be
subsequently used only in conjunction with the same service context, and never
with a different service context.

•

A call to OCIStmtPrepare2(), even if the session does not have a statement cache,
also allocates the statement handle. Therefore, applications using only
OCIStmtPrepare2() must not call OCIHandleAlloc() for the statement handle.

•

A call to OCIStmtPrepare2() must be followed by a call to OCIStmtRelease() after the
user is done with the statement handle. If statement caching is used, this releases
the statement to the cache. If statement caching is not used, the statement is
deallocated. Do not call OCIHandleFree() to free the memory.

•

If the call to OCIStmtPrepare2() is made with the OCI_PREP2_CACHE_SEARCHONLY mode
and a NULL statement was returned (statement was not found), the subsequent call
to OCIStmtRelease() is not required and must not be performed.

•

Do not call OCIStmtRelease() for a statement that was prepared using
OCIStmtPrepare().

•

The statement cache has a maximum size (number of statements) that can be
modified by an attribute on the service context, OCI_ATTR_STMTCACHESIZE. The
default value is 20. This attribute can also be used to enable or disable statement
caching for the session, pooled or nonpooled. If OCISessionBegin() is called without
the mode set as OCI_STMT_CACHE, then OCI_ATTR_STMTCACHESIZE can be set on the
service context to a nonzero attribute to turn on statement caching. If statement
caching is not turned on at the session pool level, OCISessionGet() returns a nonstatement cache-enabled session. You can use OCI_ATTR_STMTCACHESIZE to turn the
caching on. Similarly, you can use the same attribute to turn off statement caching
by setting the cache size to zero.

•

You can tag a statement at the release time so that the next time you can request
a statement of the same tag. The tag is used to search the cache. An untagged
statement (tag is NULL) is a special case of a tagged statement. Two statements
are considered different if they differ in their tags, or if one is untagged and the
other is not.

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Chapter 15

Statement Caching in OCI

See Also:
•

OCIStmtPrepare2()

•

OCIHandleAlloc()

•

OCIStmtRelease()

•

OCIHandleFree()

•

OCISessionBegin()

•

OCISessionGet()

•

Statement Functions

•

Service Context Handle Attributes

•

Session Pool Handle Attributes

15.1.4 Bind and Define Optimization in Statement Caching
To avoid repeated bind and define operations on statements in the cache by the
application, the application can register an opaque context with a statement taken from
the statement cache and register a callback function with the service context.
The application data such as bind and define buffers can be enclosed in the opaque
context. This context is registered with the statement the first time it is taken from the
cache. When a statement is taken from the cache the second time and onwards, the
application can reuse the bind and define buffers, that it had registered with that
statement. It is still the application's responsibility to manage the bind and defines. It
can reuse both the bind and define data and the buffers, or it can change only the data
and reuse the buffers, or it can free and reallocate the buffers if the current size is not
enough. In the last case, it must rebind and redefine. To clean up the memory
allocated by the application toward these bind and define buffers, the callback function
is called during aging out of the statement or purging of the whole cache as part of
session closure. The callback is called for every statement being purged. The
application frees the memory and does any other cleanup required, inside the callback
function. Example 15-1 shows the pseudocode.
Example 15-1
Cache

Optimizing Bind and Define Operations on Statements in the

Get the statement using OCIStmtPrepare2(...)
Get the opaque context from the statement if it exists
If opaque context does not exist
{
Allocate fetch buffers, do the OCIBindByPos, OCIDefineByPos, and so forth
Enclose the buffer addresses inside a context and set the context and
callback function on the statement
}
Execute/Fetch using the statement, and process the data in the fetch buffers.

15-5

Chapter 15

Implicit Fetching of ROWIDs

OCIStmtRelease() that statement
Next OCIStmtPrepare2()
OCIAttrGet() opaque application context from statement handle
Execute/Fetch using the statement and process the data in the fetch buffers.
OCIStmtRelease()
. . .
void callback_fn (context, statement, mode)
{
/* mode= OCI_CBK_STMTCACHE_STMTPURGE means this was called when statement was
aging out of the statement cache or if the session is ended */

}

See Also:
•
•

OCI_ATTR_STMTCACHE_CBKCTX
OCI_ATTR_STMTCACHE_CBK

15.1.5 OCI Statement Caching Code Example
Indicates where to find a working example of statement caching.
See cdemostc.c in directory demo for a working example of statement caching.

15.2 Implicit Fetching of ROWIDs
This section describes the following topics:
•

About Implicit Fetching of ROWIDs

•

Example of Implicit Fetching of ROWIDs

15.2.1 About Implicit Fetching of ROWIDs
ROWID is a globally unique identifier for a row in a database. It is created at the time the

row is inserted into the table, and destroyed when it is removed.
ROWID values have several important uses. They are unique identifiers for rows in a

table. They are the fastest way to access a single row and can show how the rows in
the table are stored.

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Chapter 15

Implicit Fetching of ROWIDs

Implicit fetching of ROWIDs in SELECT ... FOR UPDATE statements means that the ROWID is
retrieved at the client side, even if it is not one of the columns named in the select
statement. The position parameter of OCIDefineByPos() is set to zero (0). These host
variables can be specified for retrieving the ROWID pseudocolumn values:
•

SQLT_CHR (VARCHAR2)

•

SQLT_VCS (VARCHAR)

•

SQLT_STR (NULL-terminated string)

•

SQLT_LVC (LONG VARCHAR)

•

SQLT_AFC (CHAR)

•

SQLT_AVC (CHARZ)

•

SQLT_VST (OCI String)

•

SQLT_RDD (ROWID descriptor)

The SELECT ... FOR UPDATE statement identifies the rows that are to be updated and then
locks each row in the result set. This is useful when you want to base an update on the
existing values in a row. In that case, you must ensure that another user does not
change the row.
When you specify character buffers for storing the values of the ROWIDs (for example, if
getting it in SQLT_STR format), allocate enough memory for storing ROWIDs. Remember
the differences between the ROWID data type and the UROWID data type. The ROWID data
type can only store physical ROWIDs, but UROWID can store logical ROWIDs (identifiers for
the rows of index-organized tables) as well. The maximum internal length for the ROWID
type is 10 bytes; it is 3950 bytes for the UROWID data type.
Dynamic define is equivalent to calling OCIDefineByPos() or OCIDefineByPos2() with mode
set as OCI_DYNAMIC_FETCH. Dynamic defines enable you to set up additional attributes
for a particular define handle. It specifies a callback function that is invoked at runtime
to get a pointer to the buffer into which the fetched data or a piece of it is to be
retrieved.
The attribute OCI_ATTR_FETCH_ROWID must be set on the statement handle before you
can use implicit fetching of ROWIDs, in this way:
OCIAttrSet(stmthp, OCI_HTYPE_STMT, 0, 0 , OCI_ATTR_FETCH_ROWID, errhp);

Dynamic define is not compatible with implicit fetching of ROWIDs. In normal scenarios
this mode allows the application to provide buffers for a column, for each row; that is, a
callback is invoked every time a column value is fetched.
This feature, using OCIDefineByPos() or OCIDefineByPos2() for position 0, is for fetching
an array of data simultaneously into the user buffers and getting their respective ROWIDs
at the same time. It allows for fetching of ROWIDs with SELECT....FOR UPDATE statements
even when ROWID is not one of the columns in the SELECT query. When fetching the data
one by one into the user buffers, you can use the existing attribute OCI_ATTR_ROWID.
If you use this feature to fetch the ROWIDs, the attribute OCI_ATTR_ROWID on the statement
handle cannot be used simultaneously to get the ROWIDs. You can only use one of them
at a time for a particular statement handle.

15-7

Chapter 15

Implicit Fetching of ROWIDs

See Also:
•

OCI_ATTR_FETCH_ROWID

•

OCIDefineByPos() or OCIDefineByPos2()

15.2.2 Example of Implicit Fetching of ROWIDs
Shows an example of implicit fetching of ROWIDs.
Use the fragment of a C program in Example 15-2 to build upon.
Example 15-2

Implicit Fetching of ROWIDs

#include 
int main()
{
...
text *mySql = (text *) "SELECT emp_name FROM emp FOR UPDATE";
text rowid[100][15] = {0};
text empName[100][15] = {0};
...
/* Set up the environment, error handle, etc. */
...
/* Prepare the statement - select ... for update. */

if (OCIStmtPrepare (select_p, errhp,
mySql, strlen(mySql), OCI_NTV_SYNTAX, OCI_DEFAULT))
{
printf ("Prepare failed \n");
return (OCI_ERROR);
}
/* Set attribute for implicit fetching of ROWIDs on the statement handle. */
if (OCIAttrSet(select_p, OCI_HTYPE_STMT, 0, 0, OCI_ATTR_FETCH_ROWID, errhp))
{
printf ("Unable to set the attribute - OCI_ATTR_FETCH_ROWID \n");
return OCI_ERROR;
}
/*
* Define the positions: 0 for getting ROWIDs and other positions
* to fetch other columns.
* Also, get the define conversion done implicitly by fetching
* the ROWIDs in the string format.
*/
if (OCIDefineByPos ( select_p,
&defnp0,
errhp,
0,
rowid[0],
15,
SQLT_STR,

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Chapter 15

OCI Support for Implicit Results

(void *) ind,
(void *) 0,
(void *) 0,
OCI_DEFAULT) ||
OCIDefineByPos(select_p,
&defnp1,
errhp,
1,
empName[0],
15,
SQLT_STR,
(void *) 0,
(void *) 0,
(void *) 0,
OCI_DEFAULT)
)
{
printf ("Failed to define\n");
return (OCI_ERROR);
}

/* Execute the statement. */
if (errr = OCIStmtExecute(svchp,
select_p,
errhp,
(ub4) 5,
(ub4) 0,
(OCISnapshot *) NULL,
(OCISnapshot *) NULL,
(ub4) OCI_DEFAULT))
{
if (errr != OCI_NO_DATA)
return errr;
}
printf ("Column 0 \t Column 1\n");
printf ("_________ \t ________\n");
for (i =0 ;i<5 i++)
{
printf("%s \t %s \n", rowid[i], empName[i]);
}
return OCI_SUCCESS;
}

15.3 OCI Support for Implicit Results
Beginning with Oracle Database 12c Release 1 (12.1) , PL/SQL can return results
(cursors) implicitly from stored procedures and anonymous PL/SQL blocks.
OCIStmtGetNextResult() is provided to retrieve and process the implicit results.
PL/SQL provides a subprogram RETURN_RESULT in the DBMS_SQL package to return the
result of an executed statement as shown in Example 15-3. In the current release, only
SELECT query result-sets can be implicitly returned by a PL/SQL procedure block.
OCIStmtGetNextResult() returns an OCI statement handle on which the usual OCI
define and fetch calls are done to retrieve the rows.

15-9

Chapter 15

OCI Support for Implicit Results

Example 15-4 shows a PL/SQL stored procedure to implicitly return result-sets
(cursors) to the client.
Example 15-5 shows the same approach using an anonymous PL/SQL block sent by
the client. This example shows how applications can use the implicit results feature to
implement batching of SQL statements from an OCI application. An OCI application
can dynamically form a PL/SQL anonymous block to execute multiple and variable
SELECT statements and return the corresponding cursors using DBMS_SQL.RETURN_RESULT.
Example 15-6 lists an OCI program showing how to use the OCIStmtGetNextResult()
call to retrieve and process the implicit results returned by a PL/SQL stored procedure
(see Example 15-4) or an anonymous PL/SQL block (see Example 15-5).
OCIStmtGetNextResult() can be called iteratively by the application to retrieve each
implicit result from an executed PL/SQL statement. Applications retrieve each resultset sequentially but can fetch rows from any result-set independently. The top-level
OCI statement handle tracks all the associated result-set statement handles. Freeing
or releasing the top-level OCI statement handle automatically closes and frees all the
implicit result-sets.

The attribute OCI_ATTR_IMPLICIT_RESULT_COUNT is provided on the OCI statement handle
to determine the number of implicit results available.
The rtype parameter of OCIStmtGetNextResult() returns the type of the result. In this
release only the type: OCI_RESULT_TYPE_SELECT is supported. The describe metadata of
the returned result set can be accessed similar to any SELECT ResultSet.

Note:
The following OCI code can be used in external procedures too, to fetch from
the implicit results. In that case, OCI_PREP2_IMPL_RESULTS_CLIENT should be
passed as the mode to the OCIStmtPrepare2() call.

Example 15-3

DBMS_SQL RETURN_RESULT Subprogram

procedure return_result(rc
in out sys_refcursor,
to_client in boolean default true);
procedure return_result(rc
in out integer,
to_client in boolean default true);

Example 15-4 A PL/SQL Stored Procedure to Implicitly Return Result-Sets
(Cursors) to the Client
CREATE PROCEDURE foo AS
c1 sys_refcursor;
c2 sys_refcursor;
begin
open c1 for select * from emp;
dbms_sql.return_result(c1); --return to client
-- open 1 more cursor
open c2 for select * from dept;
dbms_sql.return_result (c2); --return to client
end;

15-10

Chapter 15

OCI Support for Implicit Results

Example 15-5 An Anonymous PL/SQL Block to Implicitly Return Result-Sets
(Cursors) to the Client
declare
c1 sys_refcursor;
c2 sys_refcursor;
begin
open c1 for select * from emp;
dbms_sql.return_result (c1); --return to client
-- open 1 more cursor
open c2 for select * from dept;
dbms_sql.return_result (c2); --return to client
end;

Example 15-6 Using OCIStmtGetNextResult() to Retrieve and Process the
Implicit Results Returned by Either a PL/SQL Stored Procedure or Anonymous
Block
OCIStmt
ub4
void
ub4
char

*stmthp;
rsetcnt;
*result;
rtype;
*sql = "begin foo; end;";

/* Prepare and execute the PL/SQL procedure. */
OCIStmtPrepare2(svchp, &stmthp, errhp, (oratext *)sql, strlen(sql),
NULL, 0, OCI_NTV_SYNTAX, OCI_DEFAULT);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0,
(const OCISnapshot *)0,
(OCISnapshot *)0, OCI_DEFAULT);
/* Now check if any implicit results are available. */
OCIAttrGet((void *)stmthp, OCI_HTYPE_STMT, &rsetcnt, 0,
OCI_ATTR_IMPLICIT_RESULT_COUNT, errhp);
/* Loop and retrieve the implicit result-sets.
* ResultSets are returned in the same order as in the PL/SQL
* procedure/block.
*/
while (OCIStmtGetNextResult(stmthp, errhp, &result, &rtype,
OCI_DEFAULT) == OCI_SUCCESS)
{
/* Check the type of implicit ResultSet, currently
* only supported type is OCI_RESULT_TYPE_SELECT
*/
if (rtype == OCI_RESULT_TYPE_SELECT)
{
OCIStmt *rsethp = (OCIStmt *)result;
/* Perform normal OCI actions to define and fetch rows. */
}
else
printf("unknown result type %d\n", rtype);
/* The result set handle should not be freed by the user. */
}
OCIStmtRelease(stmthp, errhp, NULL, 0, OCI_DEFAULT); /* Releases the statement
handle. */

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Chapter 15

Client Result Cache

See Also:
•

OCIStmtGetNextResult()

•

Statement Handle Attributes for more information about the attribute
OCI_ATTR_IMPLICIT_RESULT_COUNT.

•

OCIStmtPrepare2()

15.4 Client Result Cache
OCI applications can use client memory to take advantage of the OCI result cache to
improve response times of repeated queries.

See Also:
Oracle Database Development Guide for complete information about using
the OCI client result cache

15.5 Client Statement Cache Auto-Tuning
Describes topics about client statement cache auto-tuning.
This section describes the following topics:
•

About Auto-Tuning Client Statement Cache

•

Benefit of Auto-Tuning Client Statement Cache

•

Client Statement Cache Auto-Tuning Parameters

•

Usage Examples of Client Statement Cache Auto Tuning

•

Enabling and Disabling OCI Client Auto-Tuning

•

Usage Guidelines for Auto-Tuning Client Statement Cache

15.5.1 About Auto-Tuning Client Statement Cache
Auto-tuning optimizes OCI client session features of mid-tier applications to gain
higher performance without the need to reprogram your OCI application.
Auto tuning operations like increasing or decreasing cache memory happens implicitly
during OCIStmtPrepare2() and OCIStmtRelease() calls on a periodic basis. Calling
OCIAttrGet() with OCI_ATTR_STMTCACHESIZE on the service handle gives the current
cache size being used, if you need to check.
It is possible for the coded OCI client statement cache size setting to be sub optimal.
This can happen, for example, with changing the workload causing a different working
set of SQL statements. If the size is too low, it will cause excess network activity and
more parses at the server. If the size is too high, there will be excess memory used. It
can be difficult for the client side application to always keep this cache size optimal.

15-12

Chapter 15

Client Statement Cache Auto-Tuning

Auto-tuning automatically reconfigures the OCI statement cache size on a periodic
basis. Auto-tuning is achieved by providing a deployment time setting that provides an
option to reconfigure OCI statement caching to resolve this potential performance
issue.
These settings are provided as connect string based deployment settings in the client
oraaccess.xml file that overrides manual settings to the user configuration of OCI

features.

See Also:
•

OCIStmtPrepare2()

•

OCIStmtRelease()

15.5.2 Benefit of Auto-Tuning Client Statement Cache
The more specific benefit of auto-tuning client statement cache is to transparently
detect, monitor, and adjust the statement cache size to improve performance or
decrease memory usage.
Developers and DBAs can expect to see the following benefits of using auto-tuning for
their OCI client applications:
•

Reduced time and effort in diagnosing and fixing performance problems with each
part of their system, such as statement caching

•

Minimized manual modifications needed to configurations of this OCI feature to
improve performance. Usually, this manual correction requires applications to
restart more than once with different configuration parameters, thus further
reducing the high availability of the client

•

One solution that can be used by all OCI applications to improve performance right
out-of-the-box without having to make any application changes

•

OCI applications are freed from making custom implementations (that can be error
prone) to auto-tune their OCI application to optimize performance and memory
usage. Here auto-tuning is limited to internal automatic tuning of OCI Client-side
statement cache size only.

15.5.3 Client Statement Cache Auto-Tuning Parameters
The following connection specific parameters in oraccess.xml can be set per
configuration alias or across all connect strings using default connection specific
parameters.
Values specified in the client oraaccess.xml configuration file override programmatic
settings.
This section includes the following topics:
•



•



•

Comparison of the Connection Specific Auto-Tuning Parameters

15-13

Chapter 15

Client Statement Cache Auto-Tuning

See Also:
About Specifying Defaults for Connection Parameters for more information
about setting per configuration alias or across all connect strings using
default connection specific parameters

15.5.3.1 
This parameter is optional and sets the limit for the statement caching tunable
component.

100


The limit is the maximum number of statements that can be cached per session. If
auto-tuning is enabled or not, this setting in oraaccess.xml overrides the programmatic
setting of OCI statement cache size.
If auto-tuning is enabled, this setting will be the upper bound on statement cache size
while its being dynamically tuned.
If the session is not using statement caching APIs as in OCIStmtPrepare2() and
OCIStmtRelease(), this setting is ignored.
Default values are as follows:
•

If auto-tuning is enabled, statement caching is dynamically tuned and the initial
statement cache size is set to 100 statements.

•

If auto-tuning is disabled, this setting serves as the deployment setting of
statement caching size, overriding any programmatic setting.

See Also:
•

OCIStmtPrepare2()

•

OCIStmtRelease()

•

Enabling and Disabling OCI Client Auto-Tuning

15.5.3.2 
This section specifies auto tune parameters.
If the OCI session is not using statement caching APIs as in OCIStmtPrepare2() or
OCIStmtRelease(), auto tuning parameters are ignored for that session. It is possible in
a process that some sessions or connections can have auto-tuning enabled and some
disabled.
This section includes the following topics:
•

true

15-14

Chapter 15

Client Statement Cache Auto-Tuning

•



•



See Also:
•

OCIStmtPrepare2()

•

OCIStmtRelease()

15.5.3.2.1 true
This parameter turns auto tuning on or off.
The default is auto tuning off (FALSE) or disabled.

true


Auto-tuning is enabled along with internal default settings.

See Also:
 for more information about auto-tuning is enabled along
with internal default settings

15.5.3.2.2 
This parameter is optional.

true
0.1


The default value is 0.01%. It is specified as percentage of installed RAM. This
specifies the total memory available across the auto tuning sessions in a process
sharing this setting. This setting can be specified per process or per connect string
alias.
Note that if specified per connect string alias, the total auto tuning memory used by a
client process can add up.
Therefore, it may be preferable to specify auto tuning limits in the 
section of oraaccess.xml file. This way you have a common pool of memory for all
sessions in a client process.
A smaller limit uses less RAM for auto tuning, but minimizes the chance other
programs running on the system do not degrade in performance.
This parameter must be specified within the  deployment
setting.

15-15

Chapter 15

Client Statement Cache Auto-Tuning

See Also:
About oraaccess.xml

15.5.3.2.3 
This parameter is optional.

true
40M


Specified in bytes. Default is undefined. It specifies the total memory available across
the auto tuning sessions in a process sharing this setting. This setting can be specified
per process or per connect string alias.
Note that if specified per connect string alias, the total auto tuning memory used by a
client process can add up.
Therefore, it may be preferable to specify auto tuning limits in the 
section of oraaccess.xml file. This way you have a common pool of memory for all
sessions in a client process.
This parameter must be specified within the  deployment
setting.
Using this parameter ensures the use of a consistent memory limit for auto tuning
irrespective of installed RAM on that system.
If not specified, the auto tuning memory limit is based on the 
parameter setting.
If both  and  parameters are specified, the effective
limit is the minimum of the two parameters.

See Also:
About oraaccess.xml

15.5.3.3 Comparison of the Connection Specific Auto-Tuning Parameters
Lists and describes a comparison of all auto-tuning parameters.
Table 15-1 shows a comparison of the connection specific auto-tuning parameters.

15-16

Chapter 15

Client Statement Cache Auto-Tuning

Table 15-1

Comparison of Some Connection Specific Auto-Tuning Parameters

Parameter

Setting and Semantics

For Auto-Tuning or Deployment
Setting



Optional setting.

If auto-tuning is enabled (see "Enabling
and Disabling OCI Client Auto-Tuning"),
this is the upper bound of each sessions
statement cache size while its tuned by
auto tuning.

Per session cache size.

Or else it refers to the deployment
setting for statement caching.


Optional setting.

Only auto-tuning related

Specify this parameter to use
auto-tuning. Applies to all
connections using this
connect string or all
connections if null connect
string is specified.
0.1

Optional setting.
Converts the percentage
setting to a memory value
based on installed RAM on
that client or mid-tier system.

Only auto-tuning related. If auto-tuning is
disabled, this parameter setting is
ignored. This parameter must be
specified within the  deployment setting.

This is the upper limit of
memory used for auto tuning
within a client process.
For installed RAM of 8GB, not
specifying this parameter
gives 800 KB of memory
among the sessions.
Note each connection can
potentially have its own
setting of auto tuning
parameters so these values
can add up for the whole
process based on
configuration settings. It is
preferable to use this
parameter hence in the

section of the oraaccess.xml
file. See "File (oraaccess.xml)
Properties" for a description of
the syntax.

15-17

Chapter 15

Client Statement Cache Auto-Tuning

Table 15-1

(Cont.) Comparison of Some Connection Specific Auto-Tuning Parameters

Parameter

Setting and Semantics

For Auto-Tuning or Deployment
Setting

1048576

Optional setting.

Only auto-tuning related. If auto-tuning is
disabled, this parameter setting is
ignored. This parameter must be
specified within the  deployment setting.

This is the upper limit of
memory used for auto tuning
within a client process.
Note each connection can
potentially have its own
setting of auto tuning
parameters so these values
can add up for the whole
process based on
configuration settings. It is
preferable to use this
parameter hence in the

section of the oraaccess.xml
file.
See "File (oraaccess.xml)
Properties" for a description of
the syntax.
Value is in bytes. 1,048,576
bytes is 1 MB.

15.5.4 Usage Examples of Client Statement Cache Auto Tuning
The following are some usage examples showing use and interaction of client
statement cache auto-tuning parameters that are also connection specific parameters.

100


The programmatic statement cache size will be replaced by this setting. Auto-tuning is
disabled and cache is managed per LRU. In this case, the application developer
believes the OCI application statement prefetching programmatic settings do not need
to be overridden.

true


Auto-tuning is enabled along with internal default settings.

100


true
40M


15-18

Chapter 15

Client Statement Cache Auto-Tuning

This statement caching deployment setting of 100 will replace the programmatic
statement cache size and because auto-tuning is enabled, statement caching will be
auto-tuned. The memory target setting is in effect because auto-tuning is enabled.
Auto tuning will always try to limit total statement cache memory used around a
memory target. If a memory target is not specified, it is based on the percentage of
total installed RAM.
In this case, the memory limit is the specified memory target.

See Also:
 for more information about auto-tuning is enabled along
with internal default settings

15.5.5 Enabling and Disabling OCI Client Auto-Tuning
Describes conditions that enable and disable OCI client auto-tuning.
The following conditions enable and disable OCI client auto-tuning:
•

Auto-tuning is enabled when the client oraaccess.xml  section is added
with enable specified as true, true

•

Auto-tuning is disabled by default or when enable is set to false, false in oraaccess.xml under the  section.

15.5.6 Usage Guidelines for Auto-Tuning Client Statement Cache
Describes guidelines to use when setting the auto-tuning parameters.
The following are some guidelines to use when setting the auto-tuning parameters:
•

When either client response, memory allocation, or client CPU is high and you
want to gain performance without rebuilding the OCI application, you can use
 settings or deployment  settings. Auto tuning may
also decrease the network bytes transferred between client and server.

•

When AWR or ADDM reports lots of parses and you cannot or you may prefer not
to programmatically modify the statement cache size, you can specify auto-tuning
for statement cache or use the deployment statement cache setting
.

15-19

16
Database Startup and Shutdown
This chapter describes topics about OCI database startup and shutdown.
This section describes the following topics:
•

About OCI Database Startup and Shutdown

•

Examples of Startup and Shutdown in OCI

16.1 About OCI Database Startup and Shutdown
The OCI functions OCIDBStartup() and OCIDBShutdown() provide the minimal interface
needed to start and shut down an Oracle database.
Before calling OCIDBStartup(), the C program must connect to the server and start a
SYSDBA or SYSOPER session in the preliminary authentication mode. This mode is the only
one permitted when the instance is not up, and it is used only to start the instance. A
call to OCIDBStartup() starts one server instance without mounting or opening the
database. To mount and open the database, end the preliminary authentication
session and start a regular SYSDBA or SYSOPER session to execute the appropriate ALTER
DATABASE statements.
An active SYSDBA or SYSOPER session is needed to shut down the database. For all
modes other than OCI_DBSHUTDOWN_ABORT, make two calls to OCIDBShutdown(): one to
initiate shutdown by prohibiting further connections to the database, followed by the
appropriate ALTER DATABASE commands to dismount and close it; and the other call to
finish shutdown by bringing the instance down. In special circumstances, to shut down
the database as fast as possible, call OCIDBShutdown() in the OCI_DBSHUTDOWN_ABORT
mode, which is equivalent to SHUTDOWN ABORT in SQL*Plus.
Both of these functions require a dedicated connection to the server. ORA-106 is
signaled if an attempt is made to start or shut down the database when it is connected
to a shared server through a dispatcher.
The OCIAdmin administration handle C data type is used to make the interface
extensible. OCIAdmin is associated with the handle type OCI_HTYPE_ADMIN. Passing a
value for the OCIAdmin parameter, admhp, is optional for OCIDBStartup() and is not
needed by OCIDBShutdown().

See Also:
•

OCIDBStartup()

•

OCIDBShutdown()

•

Administration Handle Attributes

•

Oracle Database Administrator’s Guide

16-1

Chapter 16

Examples of Startup and Shutdown in OCI

16.2 Examples of Startup and Shutdown in OCI
To perform a startup, you must be connected to the database as SYSOPER or SYSDBA in
OCI_PRELIM_AUTH mode. You cannot be connected to a shared server through a
dispatcher.
To use a client-side parameter file (pfile), the attribute OCI_ATTR_ADMIN_PFILE must be
set in the administration handle using OCIAttrSet(); otherwise, a server-side parameter
file (spfile) is used. In the latter case, pass (OCIAdmin *)0. A call to OCIDBStartup()
starts one instance on the server.
Example 16-1 shows sample code that uses a client-side parameter file (pfile) that is
set in the administration handle and performs a database startup operation.
To perform a shutdown, you must be connected to the database as SYSOPER or SYSDBA.
You cannot be connected to a shared server through a dispatcher. When shutting
down in any mode other than OCI_DBSHUTDOWN_ABORT, use the following procedure:
1.

Call OCIDBShutdown() in OCI_DEFAULT, OCI_DBSHUTDOWN_TRANSACTIONAL,
OCI_DBSHUTDOWN_TRANSACTIONAL_LOCAL, or OCI_DBSHUTDOWN_IMMEDIATE mode to prohibit
further connections.

2.

Use the necessary ALTER DATABASE commands to close and dismount the database.

3.

Call OCIDBShutdown() in OCI_DBSHUTDOWN_FINAL mode to shut down the instance.

Example 16-1

Calling OCIDBStartup() to Perform a Database Startup Operation

...
/* Example 0 - Startup: */
OCIAdmin *admhp;
text *mount_stmt = (text *)"ALTER DATABASE MOUNT";
text *open_stmt = (text *)"ALTER DATABASE OPEN";
text *pfile = (text *)"/ade/viewname/oracle/work/t_init1.ora";
/* Start the authentication session */
checkerr(errhp, OCISessionBegin (svchp, errhp, usrhp,
OCI_CRED_RDBMS, OCI_SYSDBA|OCI_PRELIM_AUTH));
/* Allocate admin handle for OCIDBStartup */
checkerr(errhp, OCIHandleAlloc((void *) envhp, (void **) &admhp,
(ub4) OCI_HTYPE_ADMIN, (size_t) 0, (void **) 0));
/* Set attribute pfile in the admin handle
(do not do this if you want to use the spfile) */
checkerr (errhp, OCIAttrSet( (void *) admhp, (ub4) OCI_HTYPE_ADMIN,
(void *) pfile, (ub4) strlen(pfile),
(ub4) OCI_ATTR_ADMIN_PFILE, (OCIError *) errhp));
/* Start up in NOMOUNT mode */
checkerr(errhp, OCIDBStartup(svchp, errhp, admhp, OCI_DEFAULT, 0));
checkerr(errhp, OCIHandleFree((void *) admhp, (ub4) OCI_HTYPE_ADMIN));
/* End the authentication session */
OCISessionEnd(svchp, errhp, usrhp, (ub4)OCI_DEFAULT);
/* Start the sysdba session */
checkerr(errhp, OCISessionBegin (svchp, errhp, usrhp, OCI_CRED_RDBMS,

16-2

Chapter 16

Examples of Startup and Shutdown in OCI

OCI_SYSDBA));
/* Mount the database */
checkerr(errhp, OCIStmtPrepare2(svchp, &stmthp, errhp, mount_stmt, (ub4)
strlen((char*) mount_stmt),
(CONST OraText *) 0, (ub4) 0, (ub4) OCI_NTV_SYNTAX, (ub4)
OCI_DEFAULT));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4)0,
(OCISnapshot *) NULL, (OCISnapshot *) NULL, OCI_DEFAULT));
checkerr(errhp, OCIStmtRelease(stmthp, errhp, (OraText *)0, 0, OCI_DEFAULT));
/* Open the database */
checkerr(errhp, OCIStmtPrepare2(svchp, &stmthp, errhp, open_stmt, (ub4)
strlen((char*) open_stmt),
(CONST OraText *)0, (ub4)0, (ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4)0,
(OCISnapshot *) NULL, (OCISnapshot *) NULL, OCI_DEFAULT));
checkerr(errhp, OCIStmtRelease(stmthp, errhp, (OraText *)0, 0, OCI_DEFAULT));
/* End the sysdba session */
OCISessionEnd(svchp, errhp, usrhp, (ub4)OCI_DEFAULT);
...

Example 16-2

Calling OCIDBShutdown() in OCI_DBSHUTDOWN_FINAL Mode

/* Example 1 - Orderly shutdown: */
...
text *close_stmt = (text *)"ALTER DATABASE CLOSE NORMAL";
text *dismount_stmt = (text *)"ALTER DATABASE DISMOUNT";
/* Start the sysdba session */
checkerr(errhp, OCISessionBegin (svchp, errhp, usrhp, OCI_CRED_RDBMS,
OCI_SYSDBA));
/* Shutdown in the default mode (transactional, transactional-local,
immediate would be fine too) */
checkerr(errhp, OCIDBShutdown(svchp, errhp, (OCIAdmin *)0, OCI_DEFAULT));
/* Close the database */
checkerr(errhp, OCIStmtPrepare2(svchp, &stmthp, errhp, close_stmt, (ub4)
strlen((char*) close_stmt),
(CONST OraText *)0, (ub4)0, (ub4) OCI_NTV_SYNTAX,
(ub4) OCI_DEFAULT));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4)0,
(OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT));
checkerr(errhp, OCIStmtRelease(stmthp, errhp, (OraText *)0, 0, OCI_DEFAULT));
/* Dismount the database */
checkerr(errhp, OCIStmtPrepare2(svchp, &stmthp, errhp, dismount_stmt,
(ub4) strlen((char*) dismount_stmt), (CONST OraText *)0, (ub4)0,
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4)0,
(OCISnapshot *) NULL,
(OCISnapshot *) NULL, OCI_DEFAULT));
checkerr(errhp, OCIStmtRelease(stmthp, errhp, (OraText *)0, 0, OCI_DEFAULT));
/* Final shutdown */
checkerr(errhp, OCIDBShutdown(svchp, errhp, (OCIAdmin *)0,
OCI_DBSHUTDOWN_FINAL));

16-3

Chapter 16

Examples of Startup and Shutdown in OCI

/* End the sysdba session */
checkerr(errhp, OCISessionEnd(svchp, errhp, usrhp, (ub4)OCI_DEFAULT));
...

Example 16-3

Calling OCIDBShutdown() in OCI_DBSHUTDOWN_ABORT Mode

/* Example 2 - Shutdown using abort: */
...
/* Start the sysdba session */
...
checkerr(errhp, OCISessionBegin (svchp, errhp, usrhp, OCI_CRED_RDBMS,
OCI_SYSDBA));
/* Shutdown in the abort mode */
checkerr(errhp, OCIDBShutdown(svchp, errhp, (OCIAdmin *)0,
OCI_DBSHUTDOWN_ABORT));
/* End the sysdba session */
checkerr(errhp, OCISessionEnd(svchp, errhp, usrhp, (ub4)OCI_DEFAULT));
...

Example 16-2 shows sample code that uses a client-side parameter file (pfile) that is
set in the administration handle that performs an orderly database shutdown
operation.
Example 16-3 shows a shutdown example that uses OCI_DBSHUTDOWN_ABORT mode.

See Also:
•

OCIAttrSet()

•

OCIDBStartup()

•

OCIDBShutdown()

16-4

17
Support for Pluggable Databases
The multitenant architecture enables an Oracle database to contain a portable
collection of schemas, schema objects, and nonschema objects that appear to an
Oracle client as a separate database.
A multitenant container database (CDB) is an Oracle database that includes one or
more pluggable databases (PDBs).
OCI clients can connect to a PDB using a service whose pluggable database property
has been set to the relevant PDB.
In general, OCI calls behave the same way whether connected to a pluggable
database or a normal database. OCI calls and features that require special
consideration with a CDB are described in the sections that follow:
•

Enhancements on OCI API Calls with Multitenant Container Databases (CDB) in
General

•

OCI Enhancements for ALTER SESSION SET CONTAINER

•

Restrictions on OCI API Calls with Multitenant Container Databases (CDB) in
General

•

Restrictions on OCI Calls with ALTER SESSION SET CONTAINER

•

Restrictions on OCI Calls with ALTER SESSION SWITCH CONTAINER SWITCH
SERVICE

See Also:
Oracle Database Administrator’s Guide for more information about PDBs and
for more details about configuring the services to connect to various PDBs

17.1 Enhancements on OCI API Calls with Multitenant
Container Databases (CDB) in General
These enhancements are the result of restrictions that are now removed for Oracle
Database 12c Release 2 (12.2) and later.
The following enhancements are the result of restrictions that are now removed for
Oracle Database 12c Release 2 (12.2) and later.
•

Client result cache works with connections to Pluggable Databases.

17-1

Chapter 17

OCI Enhancements for ALTER SESSION SET CONTAINER

17.2 OCI Enhancements for ALTER SESSION SET
CONTAINER
Some OCI restrictions about using the ALTER SESSION SET CONTAINER statement are
removed.
The client must be Oracle Database Release 12c Release 2 (12.2) to perform these
operations. Lower version clients are returned an error if any of the following
operations is attempted.
•

The ALTER SESSION SET CONTAINER statement supports applications that
use TIMESTAMP WITH TIMEZONE or TIMESTAMP WITH LOCAL TIMEZONE data types in OCI.
The semantics of these types are preserved when the application switches
between pluggable databases having different database time zone settings or
different database time zone file version settings.

•

The ALTER SESSION SET CONTAINER statement supports the use of this command to
switch an OCI connection between any two pluggable databases whose character
sets are different.

17.3 Restrictions on OCI API Calls with Multitenant
Container Databases (CDB) in General
Descriptions general restrictions.
•

An attempt to logon in OCI_PRELIM_AUTH mode when connected to any container
other than CDB$ROOT will result in an ORA-24542 error.

•

An attempt to issue OCIDBStartup() when connected to any container other than
CDB$ROOT results in an ORA-24543 error.

•

An attempt to issue OCIDBShutdown() when connected to any container other than
CDB$ROOT results in an ORA-24543 error. When OCIDBShutdown() is issued connected
to CDB$ROOT, it brings down the whole instance.

•

OCI Continuous Query Notification (CQN) is not supported with CDB.

•

OCI applications linked against a client library older than release 12.1 or higher
and connecting to a pluggable database will not be able to utilize Fast Application
Notification (FAN) High Availability (HA) functionality when connected as a normal
(non-common) user. As a workaround, such applications should connect as a
common user. This restriction does not exist for release 12.1 or higher OCI clients.

See Also:
•

OCIDBStartup()

•

OCIDBShutdown()

17-2

Chapter 17

Restrictions on OCI Calls with ALTER SESSION SET CONTAINER

17.4 Restrictions on OCI Calls with ALTER SESSION SET
CONTAINER
Describes specific restrictions.
The ALTER SESSION SET CONTAINER statement can be used to switch an OCI connection
from one pluggable database to another. However, applications that use the ALTER
SESSION SET CONTAINER statement to switch between pluggable databases need to
ensure that their usage is consistent with the OCI restrictions described as follows.
•

The ALTER SESSION SET CONTAINER statement is disallowed for OCI migratable
sessions (such as sessions created with OCI_MIGRATE mode during logon) and the
combination results in an ORA-65135 error.

•

The ALTER SESSION SET CONTAINER statement is not supported with OCI connection
pool (which is the old OCI connection pool API) and the combination results in an
ORA-65135 error.

•

The ALTER SESSION SET CONTAINER statement is not supported in conjunction with
OCI session switching (wherein multiple OCI user handles share the same OCI
server handle).

•

If the client initially connects to a container with a EXTENDED MAX_STRING_SIZE setting,
and then within the same session switches to a container (using an ALTER SESSION
SET CONTAINER statement) with an STANDARD MAX_STRING_SIZE setting, then a
subsequent OCIStmtExecute() call will result in an ORA-14697 error if an attempt is
made to use any bind variables of size greater than 4000 bytes.

•

An attempt to fetch from an OCI statement handle using OCIStmtFetch() or
OCIStmtFetch2() in the context of a different container than the one in which it was
executed will result in an ORA-65108 error.

•

OCI client result cache is disabled if an ALTER SESSION SET CONTAINER statement is
done in OCI.

•

Fast Application Notification (FAN) and Runtime Connection Load Balancing
notifications are not supported for applications that switch connections between
pluggable databases using an ALTER SESSION SET CONTAINER statement.

•

The ALTER SESSION SET CONTAINER statement sets the current transaction, if any, to
read only and any attempt to perform any of the OCI transaction calls
(OCITransStart(), OCITransDetach(), OCITransCommit(), OCITransRollback(),
OCITransPrepare(), OCITransMultiPrepare(), OCITransForget()) will return an error in
the new container. In order to issue any of these calls, you need to switch back to
the original container.

•

If an OCISubscriptionUnRegister() call is attempted in the context of an incorrect
container (different from the container on which the corresponding
OCISubscriptionRegister() call was done), then an ORA-24950 is returned.

•

A OCIDescribeAny() call with OCI_PTYPE_DATABASE describes the database to which
the connection is connected. After an ALTER SESSION SET CONTAINER statement is
done, if the application wants to see the current database description, the
OCIDescribeAny() call will need to be reissued.

•

Calls to any OCI Any Data, collection, or object functions that are used to
manipulate an object from a different container are not supported.

17-3

Chapter 17

Restrictions on OCI Calls with ALTER SESSION SWITCH CONTAINER SWITCH SERVICE

•

An OCIObjectFlush() call is supported only in the container where the object
instance was created with an OCIObjectNew() call.

•

Oracle recommends that OCIObjectFlush() be called prior to switching containers
with an ALTER SESSION SET CONTAINER statement. Note that an OCIObjectFlush() call
will start a transaction if one is not already started.

•

An OCIObjectFlush() call done after switching containers may return an error if a
transaction was already started earlier on another container by the same session
(either as a result of explicit DMLs or as a result of an OCIObjectFlush()call).

•

An OCIObjectFlush() call only flushes objects dirtied in the context of the container
in which the OCIObjectFlush() call is issued.

•

Various session attributes may change on an ALTER SESSION SET CONTAINER
statement. If an application caches these attributes, their settings may no longer
be the same after an ALTER SESSION SET CONTAINER statement. Examples of
attributes that can be obtained with an OCIAttrGet() call and which can change on
an ALTER SESSION SET CONTAINER statement include the following:
–

OCI_ATTR_CURRENT_SCHEMA

–

OCI_ATTR_INITIAL_CLIENT_ROLES

–

OCI_ATTR_EDITION

–

OCI_ATTR_MAX_OPEN_CURSORS

See Also:
•

Oracle Database SQL Language Reference for more information about
MAX_STRING_SIZE

•

OCIStmtExecute()

•

OCIStmtFetch() or OCIStmtFetch2()

•

OCITransStart(), OCITransDetach(), OCITransCommit(),
OCITransRollback(), OCITransPrepare(), OCITransMultiPrepare() ,
OCITransForget()

•

OCISubscriptionUnRegister() and OCISubscriptionRegister()

•

OCIDescribeAny()

•

OCIObjectFlush()

•

OCIObjectNew()

•

OCIAttrGet()

17.5 Restrictions on OCI Calls with ALTER SESSION
SWITCH CONTAINER SWITCH SERVICE
Describes a restriction on OCI calls with the ALTER SESSION SWITCH CONTAINER SWITCH
SERVICE statement.

17-4

Chapter 17

Restrictions on OCI Calls with ALTER SESSION SWITCH CONTAINER SWITCH SERVICE

Beginning with Oracle Database 12c Release 2 (12.2), the ALTER SESSION SWITCH
CONTAINER SWITCH SERVICE statement is added, which may result in a change of service
attributes if the new service is configured differently than when connected to the
original service. However, OCI will not alter its processing based on the new settings
with this statement; instead, it will continue to use the original settings as when
connected to the original service. For example, FAN on/off, TAF on/off settings, and so
forth will remain the same as when first connected to the original service. This is
considered the desired behavior after the switch as the normal use case for the ALTER
SESSION SWITCH CONTAINER SWITCH SERVICE statement is in a multitenant environment
with the same application being in use after the switch.

17-5

18
OCI Interface for Using Shards
This chapter describes the OCI interface for using Oracle Sharding.
Shards are locations in a set of databases where each database stores some part of
the data. The part of the data stored at each database is represented by a set of
chunks, where each chunk is associated with a certain range of the data.
To make requests that read from or write to a chunk, your application must be routed
to the appropriate database (shard) that stores that chunk during the connection
initiation step. This routing is accomplished by using a data key. The data key enables
routing to the specific chunk by specifying its sharding key or to a group of chunks by
specifying its super sharding key. In order to get a connection to the correct shard
containing the chunk you wish to operate on, you must specify a key in your
application before getting a connection to a sharded Oracle database for either
standalone connections or connections obtained from an OCI Session pool. For an
OCI Session pool, you must specify a data key before you check out connections from
the pool.
For OCI Session pools and stand alone connections, the steps to form sharding keys
and shard group keys and get a session with an underlying connection include:
1.

2.

Allocate the sharding key descriptor by calling OCIDescriptorAlloc() and specifying
the descriptor type parameter as OCI_DTYPE_SHARDING_KEY to form the sharding key.
a.

Add all of the columns of the sharding key by calling
OCIShardingKeyColumnAdd() as many times as is needed to form the complete
sharding key.

b.

Call OCIAttrSet() and specify the OCI_ATTR_SHARDING_KEY attribute to set the
sharding key on the authentication handle.

Allocate the shard group key descriptor by calling OCIDescriptorAlloc() and
specifying the descriptor type parameter as OCI_DTYPE_SHARDING_KEY to form the
shard group key.
a.

Add all of the group columns of the sharding key by calling
OCIShardingKeyColumnAdd() as many times as is needed to form the complete

shard group key.
b.
3.

Call OCIAttrSet() and specify the OCI_ATTR_SUPER_SHARDING_KEY attribute to set
the shard group key on the authentication handle.

Call OCISessionGet() using the initialized authentication handle from the previous
step containing the sharding key and shard group key information to get the
database connection to the shard and chunk specified by the sharding key and
group of chunks as specified by the shard group key.

For custom pools, the steps to form sharding keys and shard group keys and check
out a connection from the pool include:
1.

If there are no existing connections in your custom pool, go directly to Step 7.
Otherwise, do the following steps.

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Chapter 18

2.

Allocate the sharding key descriptor by calling OCIDescriptorAlloc() and specifying
the descriptor type parameter as OCI_DTYPE_SHARDING_KEY to form the sharding key.
Add all of the columns of the sharding key by calling OCIShardingKeyColumnAdd() as
many times as is needed to form the complete sharding key.

3.

Allocate the shard group key descriptor by calling OCIDescriptorAlloc() and
specifying the descriptor type parameter as OCI_DTYPE_SHARDING_KEY to form the
shard group key. Add all of the group columns of the sharding key by calling
OCIShardingKeyColumnAdd() as many times as is needed to form the complete shard
group key.

4.

Call OCIShardInstancesGet() with the sharding key, super sharding key descriptors
and the connect string to return the instance name or names that contain the
desired chunk for the specified sharding key descriptor and super sharding key
descriptor.

5.

Examine each connection in the custom pool to see if it points to one of the
instances whose name was returned by OCIShardInstancesGet(). To check the
instance that a connection in your custom pool points to, you can get the instance
name using OCI_ATTR_INSTNAME on the service context handle (OCISvcCtx *).

6.

If you find a suitable connection in your custom pool that points to one of the
desired instances, then call OCIAttrSet() to associate the sharding key and super
sharding key with that connection. Now the connection is ready for executing your
application's OCI calls on the desired shard. You can skip Step 7. If you do not
find a suitable connection in your custom pool that points to the desired instance,
continue to Step 7.

7.

If there is no matching connection found, create a new connection with the
sharding key, super sharding key, and connect string and call OCISessionGet() and
specify the OCI_SESSGET_CUSTOM_POOL mode to explicitly cache the shard topology
that contains the shard to chunking mapping information. Now you have a
connection to the desired shard. Now the connection is ready for executing your
application's OCI calls on the desired shard.

Providing the sharding key or a super sharding key to OCI enables it to get a
connection to the desired shard. As previously noted, these keys must be specified
before getting a standalone connection to the database, or before checking out a
connection from the OCI Session pool so that an appropriate connection to the desired
shard can be returned.
In the case of custom pools, when the pool is empty, the custom pool implementer can
use the steps as described above to first create standalone connections to the desired
shards by providing the sharding key and super sharding key (with
OCI_SESSGET_CUSTOM_POOL mode) to populate the custom pool, and secondly, for
subsequent requests for connections to specific shards, use the
OCIShardInstancesGet() call as described in conjunction with OCIAttrGet() of
OCI_ATTR_INSTNAME to determine if an existing connection to the desired shard already
exists in the custom pool, and if it does, then the connection can be reused.
The section describes the OCI interfaces that:
•

Create a sharding key and a super sharding key using OCI data types.

•

Create a connection specifying a sharding key and a super sharding key.

•

Specify the sharding key and super sharding key to the connection request from
an OCI session pool.

18-2

Chapter 18

•

Use custom connection pooling to get the shard name for a given connection and
to get the shard name and the chunk name, given a sharding key and super
sharding key.

About Specifying a Sharding Key and Super Sharding Keys for a Standalone
Connection
Use the OCISessionGet() call for creating the connection. This call takes an
authentication handle, authp, as input, on which various properties are set, including
the two attributes to support creating connections to specific shards:
OCI_ATTR_SHARDING_KEY for the sharding key and OCI_ATTR_SUPER_SHARDING_KEY for the
super sharding key.
About Creating a Sharding Key and Super Sharding Key
Use the OCI descriptor type OCIShardingKey for forming the sharding key and the super
sharding key. This descriptor wraps the key value (for a single part key) or multiple
values (for a compounded key).
Use the following OCIShardingKeyColumnAdd() call to add all of the columns of the key to
form the complete key.
OCIShardingKeyColumnAdd(OCIShardingKey *shardingKey,
OCIError
*errhp,
void
*col,
ub4
colLen,
ub2
colType,
ub4
mode)

You should perform this call as many times as there are columns in the compound key
(or just once for a simple sharding key) in the order in which the key is defined in the
database. The columnType parameter indicates the data type of the column.
The following table shows the supported OCI data type values for the columnType
parameter and its corresponding C data type.
OCI Data Type

C Data Type

SQLT_NUM

ub1*

SQLT_CHR

OraText*

SQLT_DATE

ub1*

SQLT_TIMESTAMP

OCIDateTime*

SQLT_RAW

ub1*

SQLT_VNU

ub1*

SQLY_INT

int*

The character key values are assumed to be in the client character set (specified by
NLS_LANG or OCIEnvNLSCreate() calls) .
After forming the sharding key and the super sharding key using
theOCIShardingKeyColumnAdd() call, the keys can be set on the authentication handle
using the sharding key attribute OCI_ATTR_SHARDING_KEY and the super sharding key
attribute OCI_ATTR_SUPER_SHARDING_KEY as follows:
OCIAttrSet(authp,
OCI_HTYPE_AUTHINFO,
shardKey,

18-3

Chapter 18

sizeof(shardKey),
OCI_ATTR_SHARDING_KEY,
errhp);
OCIAttrSet(authp,
OCI_HTYPE_AUTHINFO,
shardGroupKey,
sizeof(shardGroupKey),
OCI_ATTR_SUPER_SHARDING_KEY,
errhp);

When you use this authp parameter in an OCISessionGet() call, it will ensure that you
create a connection to the shard containing the data corresponding to the sharding key
and super sharding key values that are set.
About Getting the Actual Sharding Key and Super Sharding Key Values
If you want to know the Base64 representation of the sharding key and super sharding
key for diagnostic purposes, you can use the attribute OCI_ATTR_SHARDING_KEY_B64, on
the OCIShardingKey descriptor. The OCIAttrGet() call takes the OCIShardingKey
descriptor as input and returns the text value in base64 format of the sharding key and
super sharding key.
OCIAttrGet((dvoid *) OCIShardingKey,
(ub4)
OCI_DTYPE_SHARDING_KEY,
(dvoid *)
&sekyVale,
(ub4*)
&skeyValueLen,
OCI_ATTR_SHARDING_KEY_B64,
(OCIError *)
errhp);

In addition, you can use the OCIShardingKeyReset() call shown as follows for your
application to reset and reuse the allocated descriptor for creating a new sharding key
and super sharding key.
sword OCIShardingKeyReset(OCIShardingKey *shardKey,
OCIError
*errhp,
ub4
mode);

This section includes the following topics:
•

About Specifying a Sharding Key and Super Sharding Key for Getting a
Connection from an OCI Session Pool

•

About Specifying a Sharding Key and Super Sharding Key for Getting a
Connection from a Custom Pool

See Also:
•

OCIShardingKeyColumnAdd()

•

OCIShardingKeyReset()

18-4

Chapter 18

About Specifying a Sharding Key and Super Sharding Key for Getting a Connection from an OCI Session Pool

18.1 About Specifying a Sharding Key and Super Sharding
Key for Getting a Connection from an OCI Session Pool
This topic describes how to specify a sharding key and super sharding key to get a
connection from an OCI Session Pool.
By default, the OCISessionGet() call creates a new connection. You can also use this
call to get an existing connection from an OCI Session pool. When you use the
OCI_ATTR_SHARDING_KEY and OCI_ATTR_SUPER_SHARDING_KEY attribute settings, you can get
a connection to the desired shard from an OCI Session pool. In an OCI Session pool,
sessions in the pool can represent a variety of shards that are each authenticated by
the database credentials passed in by the OCISessionGet() call using the initialized
authentication handle authp.
The following example shows how to get a connection to the desired database shard
from an OCI Session Pool created with the homogeneous and statement caching
modes specified. Even though this example uses a homogeneous pool, you are not
restricted to that type of pool.
OCIShardingKey *shardKey, *shardGroupKey;
/* Error handling is omitted for brevity. */
/* Create a homogeneous session pool. */
checkerr(&status, errhp,
OCISessionPoolCreate(envhp, errhp,
spoolhp,
*/
(OraText **) poolName, poolNameLenp,
length */
(const OraText *) connstr, strlen(connstr),
min, max, increment,
constraints */
(OraText *) "hr", strlen((char *) "hr"),
(OraText *) apppassword,
strlen((char *) apppassword),
OCI_SPC_HOMOGENEOUS|OCI_SPC_STMTCACHE));

/* session pool handle
/* returned poolname,
/* connect string */
/* pool size
/* username */
/* password */
/* modes */

/* Allocate the sharding key and super sharding key descriptors. */
OCIDescriptorAlloc(envhp,(dvoid **)&shardKey,
OCI_DTYPE_SHARDING_KEY, 0,(dvoid **)0)))
text *name = “KK”;
text *gname = “GOLD”;
int empid = 150;
/* Add all the columns of the key to form the final sharding key. */
OCIShardingKeyColumnAdd(shardKey,(ub1*)&empid, sizeof(empid),
SQLT_INT, errhp, OCI_DEFAULT);
OCIShardingKeyColumnAdd(shardKey, name, strlen(name),
SQLT_CHAR, errhp, OCI_DEFAULT));
OCIAttrSet(authp, OCI_HTYPE_AUTHINFO,
shardKey, sizeof(shardKey),
OCI_ATTR_SHARDING_KEY, errhp);
/* Setting a shard group key. */
/* Create a shard group key, in the same way as for a sharding key. */
OCIDescriptorAlloc(envhp,(dvoid **)&shardGroupKey,
OCI_DTYPE_SHARDING_KEY, 0, (dvoid **)0));

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Chapter 18

About Specifying a Sharding Key and Super Sharding Key for Getting a Connection from a Custom Pool

/* Add the column of the key to form the final super sharding key. */
OCIShardingKeyColumnAdd(shardGroupKey, gname, strlen(gname),
SQLT_CHAR, errhp, OCI_DEFAULT));
OCIAttrSet(authp, OCI_HTYPE_AUTHINFO,
shardGroupKey, sizeof(shardGroupKey),
OCI_ATTR_SUPER_SHARDING_KEY, errhp));
/* Get the database connection from the OCI Session
checkerr(&status,
errhp, OCISessionGet(envhp, errhp,
&svchp,
*/
authp,
handle */
(OraText *) poolName, poolNameLen,
NULL, 0, NULL, NULL, NULL,
optional */
OCI_DEFAULT));

Pool. */

/* returned database connection
/* initialized authentication
/* connect string */
/* session tagging parameters:
/* modes */

Chunk Migrations and OCISessionGet() in Sharding
During chunk migrations, when a chunk migrates from one shard instance to another,
OCI Session Pool can ensure that OCISessionGet() returns a connection to an instance
having a writable chunk by implicitly doing retrials during chunk migration. This
requires that a couple of properties be set:
•

Setting READONLY_CHUNK_OK to FALSE in the connect string.

•

Setting pool handle attributes: OCI_ATTR_SPOOL_GETMODE and
OCI_ATTR_SPOOL_WAIT_TIMEOUT to OCI_SPOOL_ATTRVAL_TIMEDWAIT and a suitable time
out value in milliseconds. If the pool is unable to get a connection to a writable
instance within the time out period, OCISessionGet() returns an ORA-24495 error.

If the application can use read only chunks, it can set READONLY_CHUNK_OK=true in the
connect string. In that case a connection available to the instance with chunks marked
read-only also may be dispensed. If the application attempts any database write
operation on such a connection, it gets in return suitable errors.

18.2 About Specifying a Sharding Key and Super Sharding
Key for Getting a Connection from a Custom Pool
This topic describes features that support specifying a sharding key and super
sharding key to get a connection from a custom pool.
This section describes the following features that support applications specifying a
sharding key and super sharding key for getting a connection from a custom pool:
•

OCISessionGet() mode OCI_SESSGET_CUSTOM_POOL — Used to explicitly cache the
shard topology every time OCI connects to a new shard instance.

•

OCIShardInstancesGet() — Returns instance names for a given sharding key

descriptor, super sharding key descriptor, and connection string.

18-6

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About Specifying a Sharding Key and Super Sharding Key for Getting a Connection from a Custom Pool

OCI_ATTR_INSTNAME Attribute
If your OCI client application uses custom connection pooling, you must be able to
return connections to specific shards. To do this, you must know the shard name to
which shard a connection has been made and the sharding key and super sharding
key to shard name mapping to enable a look up for a matching connection.
This is possible when you use the attribute OCI_ATTR_INSTNAME on the service context
(svchp) for this purpose. This attribute returns the instance name for a given
connection. The instance name is unique for the shard instance pointed to by a given
connection. Every shard instance has a unique name. The following code sample
shows how this attribute is used to get the instance name from a given service context
svchp.
OraText shardName[OCI_INSTNAME_MAXLEN];
ub4 shardNameLen;
OCIAttrGet(svchp,
OCI_HTYPE_SVCCTX,
shardName,
(ub4 *) &shardNameLen,
OCI_ATTR_INSTNAME,
errhp);

OCISessionGet() mode OCI_SESSGET_CUSTOM_POOL
OCI clients that do custom pooling must use the OCISessionGet() mode
OCI_SESSGET_CUSTOM_POOL to explicitly cache the shard topology that contains the shard
to chunking mapping information every time OCI connects to a new shard not
previously visited. OCI clients that do not use custom pooling do not need to use this
mode as this caching is done implicitly, for example, when you use OCI Session
Pools.
OCIShardInstancesGet()
OCIShardInstancesGet() returns instance names for a given sharding key descriptor and

super sharding key descriptor. This method has the following signature:
sword OCIShardInstancesGet(
void
**shTopoCtx,
OCIError
*errhp,
const OraText
*connstr,
ub4
constrl,
OCIShardingKey *shardingKey,
OCIShardingKey *superShardingKey,
OCIShardinst ***shardinsts,
ub4
numShardInsts,
ub4
mode);

This call looks up the shard topology cache on the client.
If any connections were made with OCI_SESSGET_CUSTOM_POOL mode, then OCI maintains
the shard topology cache locally.
The returned value may be NULL if the shard topology cache does not yet have the
mapping either because no connections were made with OCI_SESSGET_CUSTOM_POOL or
the connections that were made so far with OCI_SESSGET_CUSTOM_POOL did not connect to
a shard that contains the chunk for the sharding key and super sharding key
requested. In either case, the custom pool should create a new connection explicitly
using OCISessionGet() with the OCI_ATTR_SHARDING_KEY and OCI_ATTR_SUPER_SHARDING_KEY

18-7

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About Specifying a Sharding Key and Super Sharding Key for Getting a Connection from a Custom Pool

attributes set as applicable with OCI_SESSGET_CUSTOM_POOL mode enabled. Doing this
adds information about the new shard to the OCI shard topology cache. Subsequent
OCIShardInstancesGet() calls will look for key ranges belonging to chunks located in
these shards and return these shard instance names.
Note that a sharding key and super sharding key may refer to multiple shards as a
result of the chunk being replicated. When the custom pool has a connection to the
desired shard, the custom pool should ensure that the OCI_ATTR_SHARDING_KEY and
OCI_ATTR_SUPER_SHARDING_KEY properties are set on the connection before dispensing.
Setting these properties ensures that the chunk usage is tracked on the database side
and to determine if there have been any chunk splits occurring on the database.

See Also:
OCIShardInstancesGet() for an example that uses custom pooling

18-8

19
OCI Object-Relational Programming
This chapter introduces the OCI facility for working with objects in an Oracle database.
It also discusses the object navigational function calls of OCI.
This chapter contains these topics:
•

OCI Object Overview

•

About Working with Objects in OCI

•

About Developing an OCI Object Application

•

About Type Inheritance

•

About Type Evolution

19.1 OCI Object Overview
OCI allows applications to access any of the data types found in Oracle Database,
including scalar values, collections, and instances of any object type.
This includes all of the following:
•

Objects

•

Variable-length arrays (varrays)

•

Nested tables (multisets)

•

References (REFs)

•

LOBs

Note:
Beginning with Oracle Database 12c Release 2 (12.2), there is a change in
the linear snapshot size from 24 bytes to 34 bytes that requires the
reconstruction of the collection image form. When an older client or server
accesses a Release 12.2 or higher database involving any access to
collections, the collection image form that contains the linear snapshot must
be converted when sending or receiving to older clients or server. This
conversion results in the performance degradation. Oracle recommends that
you use a 12.2 version of the client or server to avoid this conversion.

To take full advantage of Oracle Database object capabilities, most applications must
do more than just access objects. After an object has been retrieved, the application
must navigate through references from that object to other objects. OCI provides the
capability to do this. Through the OCI object navigational calls, an application can
perform any of the following functions on objects:
•

Creating, accessing, locking, deleting, copying, and flushing objects

19-1

Chapter 19

About Working with Objects in OCI

•

Getting references to the objects and their meta-objects

•

Dynamically getting and setting values of objects' attributes

OCI also provides the ability to access type information stored in an Oracle database.
The OCIDescribeAny() function enables an application to access most information
relating to types stored in the database, including information about methods,
attributes, and type metadata.
Applications interacting with Oracle Database objects need a way to represent those
objects in a host language format. Oracle Database provides a utility called the Object
Type Translator (OTT), which can convert type definitions in the database to C struct
declarations. The declarations are stored in a header file that can be included in an
OCI application.
When type definitions are represented in C, the types of attributes are mapped to
special C variable types. OCI includes a set of data type mapping and manipulation
functions that enable an application to manipulate these data types, and thus
manipulate the attributes of objects.
The terminology for objects can occasionally become confusing. In the remainder of
this chapter, the terms object and instance both refer to an object that is either stored
in the database or is present in the object cache.

See Also:
•

About Developing an OCI Object Application for more detail about OCI
navigational calls

•

Describing Schema Metadata for a discussion of OCIDescribeAny()

•

Object-Relational Data Types in OCI for a more detailed discussion
about functions

•

OCIDescribeAny()

19.2 About Working with Objects in OCI
Many of the programming principles that govern a relational OCI application are the
same for an object-relational application.
An object-relational application uses the standard OCI calls to establish database
connections and process SQL statements. The difference is that the SQL statements
issued retrieve object references, which can then be manipulated with the OCI object
functions. An object can also be directly manipulated as a value instance (without
using its object reference).
This section includes the following topics:
•

Basic Object Program Structure

•

Persistent Objects, Transient Objects, and Values

19-2

Chapter 19

About Working with Objects in OCI

19.2.1 Basic Object Program Structure
The basic structure of an OCI application that uses objects is essentially the same as
that for a relational OCI application.
That paradigm is reproduced here, with extra information covering basic object
functionality.
1.

Initialize the OCI programming environment. You must initialize the environment in
object mode.
Your application must include C struct representations of database objects in a
header file. These structs can be created by the programmer, or, more easily, they
can be generated by the Object Type Translator (OTT).

2.

Allocate necessary handles, and establish a connection to a server.

3.

Prepare a SQL statement for execution. This is a local (client-side) step, which
may include binding placeholders and defining output variables. In an objectrelational application, this SQL statement should return a reference (REF) to an
object.

Note:
It is also possible to fetch an entire object, rather than just a reference
(REF). If you select a referenceable object, rather than pinning it, you get
that object by value. You can also select a nonreferenceable object.
4.

Associate the prepared statement with a database server, and execute the
statement.

5.

Fetch returned results.
In an object-relational application, this step entails retrieving the REF, and then
pinning the object to which it refers. Once the object is pinned, your application
can do some or all of the following:
•

Manipulate the attributes of the object and mark it as dirty (modified)

•

Follow a REF to another object or series of objects

•

Access type and attribute information

•

Navigate a complex object retrieval graph

•

Flush modified objects to the server

6.

Commit the transaction. This step implicitly flushes all modified objects to the
server and commits the changes.

7.

Free statements and handles not to be reused, or reexecute prepared statements
again.

These steps are discussed in more detail in the remainder of this chapter.

19-3

Chapter 19

About Working with Objects in OCI

See Also:
•

Overview of OCI Program Programming

•

Fetching Embedded Objects describes fetching the entire object

•

OCI Programming Basics for information about using OCI to connect to a
server, process SQL statements, and allocate handles and the
description of the OCI relational functions in Oracle Database Access C
API

•

About Representing Objects in C Applications for information about OTT
and Using the Object Type Translator with OCI

19.2.2 Persistent Objects, Transient Objects, and Values
Instances of an Oracle type are categorized into persistent objects and transient
objects based on their lifetime.
Instances of persistent objects can be further divided into standalone objects and
embedded objects depending on whether they are referenceable by way of an object
identifier.

Note:
The terms object and instance are used interchangeably in this manual.

This section includes the following topics:
•

Persistent Objects

•

Transient Objects

•

Values

See Also:
Oracle Database Object-Relational Developer's Guide for more information
about objects

19.2.2.1 Persistent Objects
A persistent object is an object that is stored in an Oracle database.
It may be fetched into the object cache and modified by an OCI application. The
lifetime of a persistent object can exceed that of the application that is accessing it.
Once it is created, it remains in the database until it is explicitly deleted. There are two
types of persistent objects:

19-4

Chapter 19

About Working with Objects in OCI

•

Standalone instances are stored in rows of an object table, and each instance has
a unique object identifier. An OCI application can retrieve a REF to a standalone
instance, pin the object, and navigate from the pinned object to other related
objects. Standalone objects may also be referred to as referenceable objects.
It is also possible to select a referenceable object, in which case you fetch the
object by value instead of fetching its REF.

•

Embedded instances are not stored as rows in an object table. They are
embedded within other structures. Examples of embedded objects are objects that
are attributes of another object, or instances that exist in an object column of a
database table. Embedded instances do not have object identifiers, and OCI
applications cannot get REFs to embedded instances.
Embedded objects may also be referred to as nonreferenceable objects or value
instances. You may sometimes see them referred to as values, which is not to be
confused with scalar data values. The context should make the meaning clear.

Example 19-1 and Example 19-2 show SQL examples that demonstrate the difference
between these two types of persistent objects.
Objects that are stored in the object table person_tab are standalone instances. They
have object identifiers and are referenceable. They can be pinned in an OCI
application.
Objects that are stored in the manager column of the department table are embedded
objects. They do not have object identifiers, and they are not referenceable; this
means they cannot be pinned in an OCI application, and they also never need to be
unpinned. They are always retrieved into the object cache by value.
Example 19-1

SQL Definition of Standalone Objects

CREATE TYPE person_t AS OBJECT
(name
varchar2(30),
age
number(3));
CREATE TABLE person_tab OF person_t;

Example 19-2

SQL Definition of Embedded Objects

CREATE TABLE department
(deptno
number,
deptname varchar2(30),
manager
person_t);

19.2.2.2 Transient Objects
A transient object is a temporary instance whose life does not exceed that of the
application, and that cannot be stored or flushed to the server.
The application can delete a transient object at any time.
Transient objects are often created by the application using the OCIObjectNew()
function to store temporary values for computation. Transient objects cannot be
converted to persistent objects. Their role is fixed at the time they are instantiated.

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See Also:
•

About Creating Objects for more information about using OCIObjectNew()

•

OCIObjectNew()

19.2.2.3 Values
A value is referred to as being either a scalar value or as an embedded or
nonreferenceable object.
In the context of this manual, a value refers to either:
•

A scalar value that is stored in a non-object column of a database table. An OCI
application can fetch values from a database by issuing SQL statements.

•

An embedded or nonreferenceable object.

The context should make it clear which meaning is intended.

Note:
It is possible to select a referenceable object into the object cache, rather
than pinning it, in which case you fetch the object by value instead of fetching
its REF.

19.3 About Developing an OCI Object Application
This section discusses the steps involved in developing a basic OCI object application.
Figure 19-1 shows a simple program logic flow for how an application might work with
objects. For simplicity, some required steps are omitted. Each step in this diagram is
discussed in the following sections.

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Figure 19-1

Basic Object Operational Flow

Initialize OCI in
Object Mode

Pin Object

(Brings object into
client-side cache)

Operate on Object
in Cache
Mark Object
as Dirtied
Flush Changes
to Object

Refresh Object

This section includes the following topics:
•

About Representing Objects in C Applications

•

About Initializing the Environment and the Object Cache

•

About Making Database Connections

•

Retrieving an Object Reference from the Server

•

Pinning an Object

•

Manipulating Object Attributes

•

About Marking Objects and Flushing Changes

•

Fetching Embedded Objects

•

Object Meta-Attributes

•

Complex Object Retrieval

•

COR Prefetching

•

OCI Versus SQL Access to Objects

•

Pin Count and Unpinning

•

NULL Indicator Structure

•

About Creating Objects

•

About Freeing and Copying Objects

•

Object Reference and Type Reference

•

Create Objects Based on Object Views and Object Tables with Primary-KeyBased OIDs

•

Error Handling in Object Applications

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See Also:
Basic Object Program Structure

19.3.1 About Representing Objects in C Applications
Before an OCI application can work with object types, those types must exist in the
database.
Typically, you create types with SQL DDL statements, such as CREATE TYPE.
When the Oracle database processes the type definition DDL commands, it stores the
type definitions in the data dictionary as type descriptor objects (TDOs).
When your application retrieves instances of object types from the database, it must
have a client-side representation of the objects. In a C program, the representation of
an object type is a struct. In an OCI object application, you may also include a NULL
indicator structure corresponding to each object type structure.
Oracle Database provides a utility called the Object Type Translator (OTT), which
generates C struct representations of database object types for you. For example,
suppose that you have a type in your database declared as follows:
CREATE TYPE
( name
empno
deptno
hiredate
salary

emp_t AS OBJECT
VARCHAR2(30),
NUMBER,
NUMBER,
DATE,
NUMBER);

OTT produces the following C struct and corresponding NULL indicator struct:
struct emp_t
{
OCIString
OCINumber
OCINumber
OCIDate
OCINumber
};
typedef struct

* name;
empno;
deptno;
hiredate;
salary;
emp_t emp_t

struct emp_t_ind
{
OCIInd
_atomic;
OCIInd
name;
OCIInd
empno;
OCIInd
deptno;
OCIInd
hiredate;
OCIInd
salary;
};
typedef struct emp_t_ind emp_t_ind;

The variable types used in the struct declarations are special types employed by the
OCI object calls. A subset of OCI functions manipulate data of these types. These
functions are mentioned later in this chapter.

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These struct declarations are automatically written to a header file whose name is
determined by the OTT input parameters. You can include this header file in the code
files for an application to provide access to objects.

See Also:
•

Object Cache and Memory Management for application programmers
who want to use object representations other than the default structs
generated by the object cache

•

NULL Indicator Structure

•

Using the Object Type Translator with OCI for more information about
OTT

•

Object-Relational Data Types in OCI for more detail about the subset of
OCI functions that manipulate data of these variable types used in the
struct declarations employed by the OCI object calls

19.3.2 About Initializing the Environment and the Object Cache
If your OCI application is going to access and manipulate objects, it is essential that
you specify a value of OCI_OBJECT for the mode parameter of the OCIEnvCreate() call,
which is the first OCI call in any OCI application. Specifying this value for mode
indicates to the OCI libraries that your application is working with objects.
This notification has the following important effects:
•

It establishes the object runtime environment.

•

It sets up the object cache.

Memory for the object cache is allocated on demand when objects are loaded into the
cache.
If the mode parameter of OCIEnvCreate() or OCIEnvNlsCreate() is not set to OCI_OBJECT,
any attempt to use an object-related function results in an error.
The client-side object cache is allocated in the program's process space. This cache is
the memory for objects that have been retrieved from the server and are available to
your application.

Note:
If you initialize the OCI environment in object mode, your application
allocates memory for the object cache, whether or not the application
actually uses object calls.

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See Also:
•

Object Advanced Topics in OCI for a detailed explanation of the object
cache

•

OCIEnvCreate()

•

OCIEnvNlsCreate()

19.3.3 About Making Database Connections
Once the OCI environment has been properly initialized, the application can connect to
a server.
This is accomplished through the standard OCI connect calls. When you use these
calls, no additional considerations must be made because this application is accessing
objects.
Only one object cache is allocated for each OCI environment. All objects retrieved or
created through different connections within the environment use the same physical
object cache. Each connection has its own logical object cache.

See Also:
OCI Programming Steps for more information about properly initializing the
OCI environment

19.3.4 Retrieving an Object Reference from the Server
To work with objects, your application must first retrieve one or more objects from the
server.
You accomplish this by issuing a SQL statement that returns REFs to one or more
objects.

Note:
It is also possible for a SQL statement to fetch embedded objects, rather
than REFs, from a database.

In the following example, the application declares a text block that stores a SQL
statement designed to retrieve a REF to a single employee object from an object table
of employees (emp_tab) in the database, when given a particular employee number that
is passed as an input variable (:emp_num) at runtime:
text *selemp = (text *) "SELECT REF(e)
FROM emp_tab e
WHERE empno = :emp_num";

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Your application should prepare and process this statement as follows in the same
way that it would handle any relational SQL statement:
1.

Prepare an application request, using OCIStmtPrepare2().

2.

Bind the host input variable using one or more appropriate bind calls.

3.

Declare and prepare an output variable to receive the employee object reference.
Here you would use an employee object reference:
OCIRef *emp1_ref = (OCIRef *) 0; /* reference to an employee object */

When you define the output variable, set the dty data type parameter for the define
call to SQLT_REF, the data type constant for REF.
4.

Execute the statement with OCUStmtExecute().

5.

Fetch the resulting REF into emp1_ref, using OCIStmtFetch2().

At this point, you could use the object reference to access and manipulate an object or
objects from the database.

See Also:
•

Fetching Embedded Objects for more information

•

OCI Programming Basics

•

OCI Programming Steps for general information about preparing and
executing SQL statements

•

Advanced Bind Operations in OCI and Advanced Define Operations in
OCI for specific information about binding and defining REF variables

•

The demonstration programs included with your Oracle installation for a
code example showing REF retrieval and pinning. For additional
information, see OCI Demonstration Programs.

•

OCIStmtPrepare2()

•

About Representing Objects in C Applications about using an employee
object reference declaration mentioned in Step 3

•

OCIStmtExecute()

•

OCIStmtFetch2()

19.3.5 Pinning an Object
Pinning an object loads the object instance into the object cache, and enables you to
access and modify the instance's attributes and follow references from that object to
other objects, if necessary.
Upon completion of the fetch step, your application has a REF, or pointer, to an object.
The actual object is not currently available to work with. Before you can manipulate an
object, it must be pinned. Your application also controls when modified objects are
written back to the server.

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Note:
This section deals with a simple pin operation involving a single object at a
time. For information about retrieving multiple objects through complex object
retrieval, see Complex Object Retrieval.

An application pins an object by calling the function OCIObjectPin(). The parameters
for this function allow you to specify the pin option, pin duration, and lock option for the
object.
Example 19-3 shows sample code that illustrates a pin operation for the employee
reference your application retrieved in the previous section, Retrieving an Object
Reference from the Server.
In this example, process_error() represents an error-handling function. If the call to
OCIObjectPin() returns anything but OCI_SUCCESS, the error-handling function is called.
The parameters of the OCIObjectPin() function are as follows:
•

env is the OCI environment handle.

•

err is the OCI error handle.

•

emp1_ref is the reference that was retrieved through SQL.

•

(OCIComplexObject *) 0 indicates that this pin operation is not utilizing complex

object retrieval.
•

OCI_PIN_ANY is the pin option.

•

OCI_DURATION_TRANS is the pin duration.

•

OCI_LOCK_X is the lock option.

•

emp1 is an out parameter that returns a pointer to the pinned object.

Now that the object has been pinned, the OCI application can modify that object. In
this simple example, the object contains no references to other objects.
This section includes the following topic: Array Pin.
Example 19-3

Pinning an Object

if (OCIObjectPin(env, err, emp1_ref, (OCIComplexObject *) 0,
OCI_PIN_ANY,
OCI_DURATION_TRANS,
OCI_LOCK_X, &emp1) != OCI_SUCCESS)
process_error(err);

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See Also:
•

Simple Object Navigation for an example of navigation from one instance
to another

•

OCIObjectPin()

•

About Pinning an Object Copy for more information about the pin option
OCI_PIN_ANY

•

Object Duration for more information about the pin duration
OCI_DURATION_TRANS

•

About Locking Objects for Update for more information about the lock
option OCI_LOCK_X

19.3.5.1 Array Pin
Given an array of references, an OCI application can pin an array of objects by calling
OCIObjectArrayPin().

The references may point to objects of different types. This function provides the ability
to fetch objects of different types from different tables in one network round-trip.

See Also:
OCIObjectArrayPin()

19.3.6 Manipulating Object Attributes
Once an object has been pinned, an OCI application can modify its attributes.
OCI provides a set of functions for working with data types of object type structs,
known as the OCI data type mapping and manipulation functions.

Note:
Changes made to objects pinned in the object cache affect only those object
copies (instances), and not the original object in the database. For changes
made by the application to reach the database, those changes must be
flushed or committed to the server.

For example, assume that the employee object in the previous section was pinned so
that the employee's salary could be increased. Assume also that at this company,
yearly salary increases are prorated for employees who have been at the company for
less than 180 days.

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For this example, you must access the employee's hire date and check whether it is
more or less than 180 days before the current date. Based on that calculation, the
employee's salary is increased by either $5000 (for more than 180 days) or $3000 (for
less than 180 days). The sample code in Example 19-4 demonstrates this process.
Note that the data type mapping and manipulation functions work with a specific set of
data types; you must convert other types, like int, to the appropriate OCI types before
using them in calculations.
Example 19-4 points out how values must be converted to OCI data types (for
example, OCIDate, OCINumber) before being passed as parameters to the OCI data type
mapping and manipulation functions.
Example 19-4
/*
/*
/*
/*

Manipulating Object Attributes in OCI

assume that sysdate has been fetched into sys_date, a string. */
emp1 and emp1_ref are the same as in previous sections. */
err is the OCI error handle. */
NOTE: error handling code is not included in this example. */

sb4 num_days;
/* the number of days between today and hiredate */
OCIDate curr_date;
/* holds the current date for calculations */
int raise; /* holds the employee's raise amount before calculations */
OCINumber raise_num;
/* holds employee's raise for calculations */
OCINumber new_sal;
/* holds the employee's new salary */
/* convert date string to an OCIDate */
OCIDateFromText(err, (text *) sys_date, (ub4) strlen(sys_date), (text *)
NULL, (ub1) 0, (text *) NULL, (ub4) 0, &curr_date);
/* get number of days between hire date and today */
OCIDateDaysBetween(err, &curr_date, &emp1->hiredate, &num_days);
/* calculate raise based on number of days since hiredate */
if (num_days > 180)
raise = 5000;
else
raise = 3000;
/* convert raise value to an OCINumber */
OCINumberFromInt(err, (void *)&raise, (uword)sizeof(raise),
OCI_NUMBER_SIGNED, &raise_num);
/* add raise amount to salary */
OCINumberAdd(err, &raise_num, &emp1->salary, &new_sal);
OCINumberAssign(err, &new_sal, &emp1->salary);

See Also:
•

About Marking Objects and Flushing Changes for more information
about flushing changes or committing them to the server

•

Object-Relational Data Types in OCI for more information about the OCI
data types and the data type mapping and manipulation functions

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19.3.7 About Marking Objects and Flushing Changes
The application must take specific steps to ensure that changes to objects by marking
them and then flushing them are written in the database.
In Example 19-4, an attribute of an object instance was changed. At this point,
however, that change exists only in the client-side object cache. The application must
take specific steps to ensure that the change is written in the database.
The first step is to indicate that the object has been modified. This is done with the
OCIObjectMarkUpdate() function. This function marks the object as dirty (modified).
Objects that have had their dirty flag set must be flushed to the server for the changes
to be recorded in the database. You can do this in three ways:
•

Flush a single dirty object by calling OCIObjectFlush().

•

Flush the entire cache using OCICacheFlush(). In this case OCI traverses the dirty
list maintained by the cache and flushes the dirty objects to the server.

•

Call OCICacheFlush() to commit a transaction. Doing so also traverses the dirty list
and flushes the dirty objects to the server.

The flush operations work only on persistent objects in the cache. Transient objects
are never flushed to the server.
Flushing an object to the server can activate triggers in the database. In fact, on some
occasions an application may want to explicitly flush objects just to fire triggers on the
server side.

See Also:
•

OCI Support for Transactions for more information about
OCITransCommit()

•

About Creating Objects for information about transient and persistent
objects

•

Object Meta-Attributes for information about seeing and checking object
meta-attributes, such as dirty

•

OCIObjectMarkUpdate()

•

OCIObjectFlush()

•

OCICacheFlush()

•

OCICacheFlush()

19.3.8 Fetching Embedded Objects
An application must fetch embedded object instances.
If your application must fetch an embedded object instance—an object stored in a
column of a regular table, rather than an object table—you cannot use the REF retrieval
mechanism described in Retrieving an Object Reference from the Server. Embedded
instances do not have object identifiers, so it is not possible to get a REF to them; they

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cannot serve as the basis for object navigation. Many situations exist, however, in
which an application must fetch embedded instances.
For example, assume that an address type has been created.
CREATE TYPE address AS OBJECT
( street1
varchar2(50),
street2
varchar2(50),
city
varchar2(30),
state
char(2),
zip
number(5));

You could then use that type as the data type of a column in another table:
CREATE TABLE clients
( name
varchar2(40),
addr
address);

Your OCI application could then issue the following SQL statement:
SELECT addr FROM clients
WHERE name='BEAR BYTE DATA MANAGEMENT'

This statement would return an embedded address object from the clients table. The
application could then use the values in the attributes of this object for other
processing.
Your application should prepare and process this statement in the same way that it
would handle any relational SQL statement, as described in OCI Programming Basics:
•

Prepare an application request, using OCIStmtPrepare2().

•

Bind the input variable using one or more appropriate bind calls.

•

Define an output variable to receive the address instance. You use a C struct
representation of the object type that was generated by OTT, as described in
About Representing Objects in C Applications.
addr1

*address; /* variable of the address struct type */

When you define the output variable, set the dty data type parameter for the define
call to SQLT_NTY, the data type constant for named data types.
•

Execute the statement with OCIStmtExecute().

•

Fetch the resulting instance into addr1, using OCIStmtFetch2().

Following this operation, you can access the attributes of the instance, as described in
Manipulating Object Attributes, or pass the instance as an input parameter for another
SQL statement.

Note:
Changes made to an embedded instance can be made persistent only by
executing a SQL UPDATE statement.

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See Also:
•

OCI Programming Steps for more information about preparing and
executing SQL statements

•

OCIStmtPrepare2()

•

OCIStmtExecute()

•

OCIStmtFetch2()

19.3.9 Object Meta-Attributes
An object's meta-attributes serve as flags that can provide information to an
application, or to the object cache, about the status of an object.
For example, one of the meta-attributes of an object indicates whether it has been
flushed to the server. Object meta-attributes can help an application control the
behavior of instances.
Persistent and transient object instances have different sets of meta-attributes. The
meta-attributes for persistent objects are further subdivided into persistent metaattributes and transient meta-attributes. Transient meta-attributes exist only when an
instance is in memory. Persistent meta-attributes also apply to objects stored in the
server.
This section includes the following topics:
•

Persistent Object Meta-Attributes

•

Additional Attribute Functions

•

Transient Object Meta-Attributes

19.3.9.1 Persistent Object Meta-Attributes
Lists and describes the meta-attributes for standalone persistent objects.
Table 19-1 shows the meta-attributes for standalone persistent objects.
Table 19-1

Meta-Attributes of Persistent Objects

Meta‐Attributes

Meaning

existent

Does the object exist?

nullity

Null information of the instance

locked

Has the object been locked?

dirty

Has the object been marked as dirtied?

pinned

Is the object pinned?

allocation duration

See Object Duration.

pin duration

See Object Duration.

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Note:
Embedded persistent objects only have the nullity and allocation duration
attributes, which are transient.

OCI provides the OCIObjectGetProperty() function, which allows an application to check
the status of a variety of attributes of an object. The syntax of the function is:
sword OCIObjectGetProperty ( OCIEnv
OCIError
const void
OCIObjectPropId
void
ub4

*envh,
*errh,
*obj,
propertyId,
*property,
*size );

The propertyId and property parameters are used to retrieve information about any of
a variety of properties or attributes.
The different property IDs and the corresponding type of property argument follow.
OCI_OBJECTPROP_LIFETIME
This identifies whether the given object is a persistent object or a transient object or a
value instance. The property argument must be a pointer to a variable of type
OCIObjectLifetime. Possible values include:
•

OCI_OBJECT_PERSISTENT

•

OCI_OBJECT_TRANSIENT

•

OCI_OBJECT_VALUE

OCI_OBJECTPROP_SCHEMA
This returns the schema name of the table in which the object exists. An error is
returned if the given object points to a transient instance or a value. If the input buffer
is not big enough to hold the schema name, an error is returned; the error message
communicates the required size. Upon success, the size of the returned schema
name in bytes is returned by size. The property argument must be an array of type
text, and size should be set to the size of the array in bytes by the caller.
OCI_OBJECTPROP_TABLE
This returns the table name in which the object exists. An error is returned if the given
object points to a transient instance or a value. If the input buffer is not big enough to
hold the table name, an error is returned; the error message communicates the
required size. Upon success, the size of the returned table name in bytes is returned
by size. The property argument must be an array of type text and size should be set
to the size of the array in bytes by the caller.
OCI_OBJECTPROP_PIN_DURATION
This returns the pin duration of the object. An error is returned if the given object
points to a value instance. The property argument must be a pointer to a variable of
type OCIDuration. Valid values include:
•

OCI_DURATION_SESSION

•

OCI_DURATION_TRANS

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OCI_OBJECTPROP_ALLOC_DURATION
This returns the allocation duration of the object. The property argument must be a
pointer to a variable of type OCIDuration. Valid values include:
•

OCI_DURATION_SESSION

•

OCI_DURATION_TRANS

OCI_OBJECTPROP_LOCK
This returns the lock status of the object. The possible lock status is indicated by
OCILockOpt. An error is returned if the given object points to a transient or value
instance. The property argument must be a pointer to a variable of type OCILockOpt.
The lock status of an object can also be retrieved by calling OCIObjectIsLocked().
OCI_OBJECTPROP_MARKSTATUS
This returns the dirty status and indicates whether the object is a new object, updated
object, or deleted object. An error is returned if the given object points to a transient or
value instance. The property argument must be of type OCIObjectMarkStatus. Valid
values include:
•

OCI_OBJECT_NEW

•

OCI_OBJECT_DELETED

•

OCI_OBJECT_UPDATED

The following macros are available to test the object mark status:
•

OCI_OBJECT_IS_UPDATED (flag)

•

OCI_OBJECT_IS_DELETED (flag)

•

OCI_OBJECT_IS_NEW (flag)

•

OCI_OBJECT_IS_DIRTY (flag)

OCI_OBJECTPROP_VIEW
This identifies whether the specified object is an object view or not. If the property
value returned is TRUE, the object is a view; otherwise, it is not. An error is returned if
the given object points to a transient or value instance. The property argument must
be of type boolean.
Just as a view is a virtual table, an object view is a virtual object table. Each row in the
view is an object: you can call its methods, access its attributes using the dot notation,
and create a REF that points to it.

See Also:
•

OCIObjectGetProperty()

•

Object Duration for more information about durations

•

OCIObjectIsLocked()

19.3.9.2 Additional Attribute Functions
Lists and describes additional attribute functions known as set and check functions.

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OCI also provides functions that allow an application to set or check some of these
attributes directly or indirectly, as shown in Table 19-2.
Table 19-2

Set and Check Functions

Meta-Attribute

Set with

Check with

nullity



OCIObjectGetInd()

existence



OCIObjectExists()

locked

OCIObjectLock()

OCIObjectIsLocked()

dirty

OCIObjectMarkUpdate()

OCIObjectIsDirty()

19.3.9.3 Transient Object Meta-Attributes
Lists and describes transient object meta-attributes.
Transient objects have no persistent attributes. Table 19-3 shows the following
transient attributes.
Table 19-3

Transient Meta-Attributes

Transient Meta-Attributes

Meaning

existent

Does the object exist?

pinned

Is the object being accessed by the application?

dirty

Has the object been marked as dirtied?

nullity

Null information of the instance.

allocation duration

See Object Duration.

pin duration

See Object Duration.

19.3.10 Complex Object Retrieval
A complex object includes its root object and its set of logically related objects each of
which are prefetched based on a given depth level.
In Example 19-3 and Example 19-4, only a single instance at a time was fetched or
pinned. In these cases, each pin operation involved a separate server round-trip to
retrieve the object.
Object-oriented applications often model their problems as a set of interrelated objects
that form graphs of objects. The applications process these objects by starting at some
initial set of objects, and then using the references in these initial objects to traverse
the remaining objects. In a client/server setting, each of these traversals could result in
costly network round-trips to fetch objects.
Application performance with objects can be improved with complex object retrieval
(COR). This is a prefetching mechanism in which an application specifies the criteria
for retrieving a set of linked objects in a single operation.

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Note:
As described later, this does not mean that these prefetched objects are all
pinned. They are fetched into the object cache, so that subsequent pin calls
are local operations.

A complex object is a set of logically related objects consisting of a root object, and a
set of objects each of which is prefetched based on a given depth level. The root
object is explicitly fetched or pinned. The depth level is the shortest number of
references that must be traversed from the root object to a given prefetched object in a
complex object.
An application specifies a complex object by describing its content and boundary. The
fetching of complex objects is constrained by an environment's prefetch limit, the
amount of memory in the object cache that is available for prefetching objects.

Note:
The use of COR does not add functionality, but it improves performance. Its
use is optional.

Consider the following type declaration:
CREATE TYPE customer(...);
CREATE TYPE line_item(...);
CREATE TYPE line_item_varray as VARRAY(100) of REF line_item;
CREATE TYPE purchase_order AS OBJECT
( po_number
NUMBER,
cust
REF customer,
related_orders
REF purchase_order,
line_items
line_item_varray);

The purchase_order type contains a scalar value for po_number, a VARRAY of line items,
and two references. The first is to a customer type, and the second is to a
purchase_order type, indicating that this type may be implemented as a linked list.
When fetching a complex object, an application must specify the following:
•

A REF to the desired root object.

•

One or more pairs of type and depth information to specify the boundaries of the
complex object. The type information indicates which REF attributes should be
followed for COR, and the depth level indicates how many levels deep those links
should be followed.

In the preceding purchase order object, the application must specify the following:
•
•

The REF to the root purchase order object
One or more pairs of type and depth information for cust, related_orders, or
line_items

An application fetching a purchase order may very likely need access to the customer
information for that order. Using simple navigation, this would require two server

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accesses to retrieve the two objects. Through complex object retrieval, the customer
can be prefetched when the application pins the purchase order. In this case, the
complex object would consist of the purchase order object and the customer object
that it references.
In the previous example, the application would specify the purchase_order REF, and
would indicate that the cust REF attribute should be followed to a depth level of 1, as
follows:
•

REF(PO object)

•

{(customer, 1)}

For the application to prefetch the purchase_order object and all objects in the object
graph it contains, the application would specify that both the cust and related_orders
should be followed to the maximum depth level possible.
•

REF(PO object)

•

{(customer, UB4MAXVAL), (purchase_order, UB4MAXVAL)}

(In this example, UB4MAXVAL specifies that all objects of the specified type reachable
through references from the root object should be prefetched.)
For an application to fetch a PO and all the associated line items, it would specify:
•

REF(PO object)

•

{(line_item, 1)}

The application can also fetch all objects reachable from the root object by way of REFs
(transitive closure) by setting the level parameter to the depth desired. For the
preceding two examples, the application could also specify (PO object REF, UB4MAXVAL)
and (PO object REF, 1) respectively, to prefetch required objects. Although, doing so
results in many extraneous fetches, quite simple to specify and requires only one
server round-trip.
This section includes the following topics:
•

About Prefetching Objects

•

About Implementing Complex Object Retrieval in OCI

19.3.10.1 About Prefetching Objects
After specifying and fetching a complex object, subsequent fetches of objects
contained in the complex object do not incur the cost of a network round-trip, because
these objects have been prefetched and are in the object cache.
Consider that excessive prefetching of objects can lead to a flooding of the object
cache. This flooding, in turn, may force out other objects that the application had
pinned, leading to a performance degradation instead of performance improvement.

Note:
If there is insufficient memory in the cache to hold all prefetched objects,
some objects may not be prefetched. The application incurs a network
round-trip when those objects are accessed later.

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The READ or SELECT privilege is needed for all prefetched objects. Objects in the
complex object for which the application does not have READ or SELECT privilege are not
prefetched.

19.3.10.2 About Implementing Complex Object Retrieval in OCI
Complex object retrieval (COR) allows an application to prefetch a complex object
while fetching the root object.
The complex object specifications are passed to the same OCIObjectPin() function
used for simple objects.
An application specifies the parameters for complex object retrieval using a complex
object retrieval handle. This handle is of type OCIComplexObject and is allocated in the
same way as other OCI handles.
The complex object retrieval handle contains a list of complex object retrieval
descriptors. The descriptors are of type OCIComplexObjectComp, and are allocated in the
same way as other OCI descriptors.
Each COR descriptor contains a type REF and a depth level. The type REF specifies a
type of reference to be followed while constructing the complex object. The depth level
indicates how far a particular type of reference should be followed. Specify an integer
value, or specify the constant UB4MAXVAL for the maximum possible depth level.
The application can also specify the depth level in the COR handle without creating
COR descriptors for type and depth parameters. In this case, all REFs are followed to
the depth specified in the COR handle. The COR handle can also be used to specify
whether a collection attribute should be fetched separately on demand (out-of-line) as
opposed to the default case of fetching it along with the containing object (inline).
The application uses OCIAttrSet() to set the attributes of a COR handle. The attributes
are:
OCI_ATTR_COMPLEXOBJECT_LEVEL - the depth level
OCI_ATTR_COMPLEXOBJECT_COLL_OUTOFLINE - fetch collection attribute in an object type out-

of-line
The application allocates the COR descriptor using OCIDescriptorAlloc() and then can
set the following attributes:
OCI_ATTR_COMPLEXOBJECTCOMP_TYPE - the type REF
OCI_ATTR_COMPLEXOBJECTCOMP_TYPE_LEVEL - the depth level for references of the

preceding type
Once these attributes are set, the application calls OCIParamSet() to put the descriptor
into a complex object retrieval handle. The handle has an OCI_ATTR_PARAM_COUNT
attribute that specifies the number of descriptors on the handle. This attribute can be
read with OCIAttrGet().
Once the handle has been populated, it can be passed to the OCIObjectPin() call to pin
the root object and prefetch the remainder of the complex object.
The complex object retrieval handles and descriptors must be freed explicitly when
they are no longer needed.

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See Also:
•

Handles

•

OCI Descriptors

•

OCIObjectPin()

•

OCIAttrSet()

•

OCIDescriptorAlloc()

•

OCIParamSet()

•

OCIAttrGet()

•

OCIObjectPin()

19.3.11 COR Prefetching
The application specifies a complex object while fetching the root object.
The prefetched objects are obtained by doing a breadth-first traversal of the graphs of
objects rooted at a given root object. The traversal stops when all required objects
have been prefetched, or when the total size of all the prefetched objects exceeds the
prefetch limit.
This section includes the following topics:
•

COR Interface

•

Example of COR

19.3.11.1 COR Interface
The interface for fetching complex objects is the OCI pin interface.
The application can pass an initialized COR handle to OCIObjectPin() (or an array of
handles to OCIObjectArrayPin()) to fetch the root object and the prefetched objects
specified in the COR handle.
sword OCIObjectPin ( OCIEnv
OCIError
OCIRef
OCIComplexObject
OCIPinOpt
OCIDuration
OCILockOpt
void

*env,
*err,
*object_ref,
*corhdl,
pin_option,
pin_duration,
lock_option,
**object );

sword OCIObjectArrayPin ( OCIEnv
OCIError
OCIRef
ub4
OCIComplexObject
ub4
OCIPinOpt
OCIDuration
OCILockOpt

*env,
*err,
**ref_array,
array_size,
**cor_array,
cor_array_size,
pin_option,
pin_duration,
lock,

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void
ub4

**obj_array,
*pos );

Note the following points when using COR:
•

A null COR handle argument defaults to pinning just the root object.

•

A COR handle with the type of the root object and a depth level of 0 fetches only
the root object and is thus equivalent to a null COR handle.

•

The lock options apply only to the root object.

Note:
To specify lock options for prefetched objects, the application can visit all
the objects in a complex object, create an array of REFs, and lock the
entire complex object in another round-trip using the array interface
(OCIObjectArrayPin()).

See Also:
•

OCIObjectPin()

•

OCIObjectArrayPin()

•

OCIObjectArrayPin()

19.3.11.2 Example of COR
Shows how an application program can be modified to use complex object retrieval.
Example 19-5 illustrates how an application program can be modified to use complex
object retrieval.
Consider an application that displays a purchase order and the line items associated
with it. The code in boldface accomplishes this. The rest of the code uses complex
object retrieval for prefetching and thus enhances the application's performance.
Example 19-5

Using Complex Object Retrieval in OCI

OCIEnv *envhp;
OCIError *errhp;
OCIRef **liref;
OCIRef *poref;
OCIIter *itr;
boolean eoc;
purchase_order *po = (purchase_order *)0;
line_item *li = (line_item *)0;
OCISvcCtx *svchp;
OCIComplexObject *corhp;
OCIComplexObjectComp *cordp;
OCIType *litdo;
ub4 level = 0;
/* get COR Handle */

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OCIHandleAlloc((void *) envhp, (void **) &corhp, (ub4)
OCI_HTYPE_COMPLEXOBJECT, 0, (void **)0);
/* get COR descriptor for type line_item */
OCIDescriptorAlloc((void *) envhp, (void **) &cordp, (ub4)
OCI_DTYPE_COMPLEXOBJECTCOMP, 0, (void **) 0);
/* get type of line_item to set in COR descriptor */
OCITypeByName(envhp, errhp, svchp, (const text *) 0, (ub4) 0,
(const text *) "LINE_ITEM",
(ub4) strlen((const char *) "LINE_ITEM"), (text *) 0,
(ub4) 0, OCI_DURATION_SESSION,
OCI_TYPEGET_HEADER, &litdo);
/* set line_item type in COR descriptor */
OCIAttrSet( (void *) cordp, (ub4) OCI_DTYPE_COMPLEXOBJECTCOMP,
(void *) litdo, (ub4) sizeof(void *), (ub4)
OCI_ATTR_COMPLEXOBJECTCOMP_TYPE, (OCIError *) errhp);
level = 1;
/* set depth level for line_item_varray in COR descriptor */
OCIAttrSet( (void *) cordp, (ub4) OCI_DTYPE_COMPLEXOBJECTCOMP,
(void *) &level, (ub4) sizeof(ub4), (ub4)
OCI_ATTR_COMPLEXOBJECTCOMP_TYPE_LEVEL, (OCIError *) errhp);
/* put COR descriptor in COR handle */
OCIParamSet(corhp, OCI_HTYPE_COMPLEXOBJECT, errhp, cordp,
OCI_DTYPE_COMPLEXOBJECTCOMP, 1);
/* pin the purchase order */
OCIObjectPin(envhp, errhp, poref, corhp, OCI_PIN_LATEST,
OCI_DURATION_SESSION, OCI_LOCK_NONE, (void **)&po);
/* free COR descriptor and COR handle */
OCIDescriptorFree((void *) cordp, (ub4) OCI_DTYPE_COMPLEXOBJECTCOMP);
OCIHandleFree((void *) corhp, (ub4) OCI_HTYPE_COMPLEXOBJECT);
/* iterate and print line items for this purchase order */
OCIIterCreate(envhp, errhp, po->line_items, &itr);
/* get first line item */
OCIIterNext(envhp, errhp, itr, (void **)&liref, (void **)0, &eoc);
while (!eoc)
/* not end of collection */
{
/* pin line item */
OCIObjectPin(envhp, errhp, *liref, (void *)0, OCI_PIN_RECENT,
OCI_DURATION_SESSION,
OCI_LOCK_NONE, (void **)&li));
display_line_item(li);
/* get next line item */
OCIIterNext(envhp, errhp, itr, (void **)&liref, (void **)0, &eoc);
}

19.3.12 OCI Versus SQL Access to Objects
If an application must manipulate a graph of objects (interrelated by object references),
then it is more effective to use the OCI interface rather than the SQL interface for
accessing objects.

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Retrieving a graph of objects using the SQL interface may require executing multiple
SELECT statements, requiring multiple network round-trips. Using the complex object
retrieval capability provided by OCI, the application can retrieve the graph of objects in
one OCIObjectPin() call.
Consider the update case where the application retrieves a graph of objects, and
modifies it based upon user interaction, and then wants to make the modifications
persistent in the database. Using the SQL interface, the application would have to
execute multiple UPDATE statements to update the graph of objects. If the modifications
involved creation of new objects and deletion of existing objects, then execution of
corresponding INSERT and DELETE statements would also be required. In addition, the
application would have to do more bookkeeping, such as keeping track of table
names, because this information is required for executing the INSERT, UPDATE, and
DELETE statements.
Using the OCICacheFlush() function, the application can flush all modifications
(insertion, deletion, and update of objects) in a single operation. OCI does all the
bookkeeping, thereby requiring less coding in the application. For manipulating a
graph of objects OCI is not only efficient, but also provides an easy-to-use interface.
Consider a different case in which the application must fetch an object when given its
REF. In OCI, this is achieved by pinning the object using the OCIObjectPin() call. In the
SQL interface, this can be achieved by dereferencing the REF in a SELECT statement (for
example, SELECT DEREF(ref) from tbl;). Consider situations where the same REF
(reference to the same object) is being dereferenced multiple times in a transaction.
By calling OCIObjectPin() with the OCI_PIN_RECENT option, the object is fetched from the
server only once for the transaction, and repeated pins on the same REF return a
pointer to the pinned object in the cache. In the SQL interface, each execution of the
SELECT DEREF... statement would result in fetching the object from the server. This
would result in multiple round-trips to the server and multiple copies of the same
object.
Finally, consider the case in which the application must fetch a nonreferenceable
object, as in the following example:
CREATE TABLE department
(
deptno number,
deptname varchar2(30),
manager employee_t
);

The employee_t instances stored in the manager column are nonreferenceable. You can
only use the SQL interface to fetch manager column instances. But if employee_t has
any REF attributes, OCI calls can then be used to navigate the REF.

See Also:
•

OCIObjectPin()

•

OCICacheFlush()

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19.3.13 Pin Count and Unpinning
Each object in the object cache has a pin count associated with it.
The pin count indicates the number of code modules that are concurrently accessing
the object. The pin count is set to 1 when an object is pinned into the cache for the first
time. Objects prefetched with complex object retrieval enter the object cache with a pin
count of zero.
It is possible to pin an pinned object. Doing so increases the pin count by one. When a
process finishes using an object, it should unpin it, using OCIObjectUnpin(). This call
decrements the pin count by one.
When the pin count of an object reaches zero, that object is eligible to be aged out of
the cache if necessary, freeing up the memory space occupied by the object.
The pin count of an object can be set to zero explicitly by calling
OCIObjectPinCountReset().
An application can unpin all objects in the cache related to a specific connection, by
calling OCICacheUnpin().

See Also:
•

About Freeing an Object Copy for more information about the conditions
under which objects with zero pin count are removed from the cache and
about objects being aged out of the cache

•

About Marking Objects and Flushing Changes for information about
explicitly flushing an object or the entire cache

•

OCIObjectUnpin()

•

OCIObjectPinCountReset()

•

OCICacheUnpin()

19.3.14 NULL Indicator Structure
If a column in a row of a database table has no value, then that column is said to be
NULL, or to contain a NULL.
Two different types of NULLs can apply to objects:
•

Any attribute of an object can have a NULL value. This indicates that the value of
that attribute of the object is not known.

•

An object instance may be atomically NULL, meaning that the value of the entire
object is unknown.

Atomic nullity is not the same thing as nonexistence. An atomically NULL instance still
exists; its value is just not known. It may be thought of as an existing object with no
data.
When working with objects in OCI, an application can define a NULL indicator
structure for each object type used by the application. In most cases, doing so simply

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requires including the NULL indicator structure generated by OTT along with the struct
declaration. When the OTT output header file is included, the NULL indicator struct
becomes available to your application.
For each type, the NULL indicator structure includes an atomic NULL indicator (whose
type is OCIInd), and a NULL indicator for each attribute of the instance. If the type has an
object attribute, the NULL indicator structure includes that attribute's NULL indicator
structure. Example 19-6 shows the C representations of types with their corresponding
NULL indicator structures.

Note:
The dependentsAge field of person_ind indicates whether the entire varray
(dependentsAge field of person) is atomically NULL or not. NULL information of
individual elements of dependentsAge can be retrieved through the elemind
parameter of a call to OCICollGetElem(). Similarly, the prevAddr field of
person_ind indicates whether the entire nested table (prevAddr field of person)
is atomically NULL or not. NULL information of individual elements of prevAddr
can be retrieved through the elemind parameter of a call to OCICollGetElem().

For an object type instance, the first field of the NULL indicator structure is the atomic
NULL indicator, and the remaining fields are the attribute NULL indicators whose layout
resembles the layout of the object type instance's attributes.
Checking the value of the atomic NULL indicator allows an application to test whether
an instance is atomically NULL. Checking any of the others allows an application to test
the NULL status of that attribute, as in the following code sample:
person_ind *my_person_ind
if( my_person_ind -> _atomic == OCI_IND_NULL)
printf ("instance is atomically NULL\n");
else
if( my_person_ind -> fname == OCI_IND_NULL)
printf ("fname attribute is NULL\n");

In the preceding example, the value of the atomic NULL indicator, or one of the attribute
NULL indicators, is compared to the predefined value OCI_IND_NULL to test if it is NULL.
The following predefined values are available for such a comparison:
•

OCI_IND_NOTNULL, indicating that the value is not NULL

•

OCI_IND_NULL, indicating that the value is NULL

•

OCI_IND_BADNULL indicates that an enclosing object (or parent object) is NULL. This is

used by PL/SQL, and may also be referred to as an INVALID_NULL. For example,
if a type instance is NULL, then its attributes are INVALID_NULLs.
Use the function OCIObjectGetInd() to retrieve the NULL indicator structure of an object.
If you update an attribute in its C structure, you must also set the NULL indicator for that
attribute:
obj->attr1 = string1;
OCIObjectGetInd(envhp, errhp, obj, &ind);
ind->attr1 = OCI_IND_NOTNULL;

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Example 19-6 C Representations of Types with Their Corresponding NULL
Indicator Structures
struct address
{
OCINumber
OCIString
OCIString
OCIString
};
typedef struct

no;
*street;
*state;
*zip;
address address;

struct address_ind
{
OCIInd
_atomic;
OCIInd
no;
OCIInd
street;
OCIInd
state;
OCIInd
zip;
};
typedef struct address_ind address_ind;

struct person
{
OCIString
*fname;
OCIString
*lname;
OCINumber
age;
OCIDate
birthday;
OCIArray
*dependentsAge;
OCITable
*prevAddr;
OCIRaw
*comment1;
OCILobLocator *comment2;
address
addr;
OCIRef
*spouse;
};
typedef struct person person;
struct person_ind
{
OCIInd
_atomic;
OCIInd
fname;
OCIInd
lname;
OCIInd
age;
OCIInd
birthday;
OCIInd
dependentsAge;
OCIInd
prevAddr;
OCIInd
comment1;
OCIInd
comment2;
address_ind addr;
OCIInd
spouse;
};
typedef struct person_ind person_ind;

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See Also:
•

Using the Object Type Translator with OCI for more information about
OTT-generated NULL indicator structures

•

OCICollGetElem()

•

OCIObjectGetInd()

19.3.15 About Creating Objects
An OCI application can create any object using OCIObjectNew().
To create a persistent object, the application must specify the object table where the
new object resides. This value can be retrieved by calling OCIObjectPinTable(), and it is
passed in the table parameter. To create a transient object, the application must pass
only the type descriptor object (retrieved by calling OCIDescribeAny()) for the type of
object being created.
OCIObjectNew() can also be used to create instances of scalars (for example, REF, LOB,
string, raw, number, and date) and collections (for example, varray and nested table)
by passing the appropriate value for the typecode parameter.

This section includes the following topic: Attribute Values of New Objects.

See Also:
•

OCIObjectNew()

•

OCIObjectPinTable()

•

OCIDescribeAny()

19.3.15.1 Attribute Values of New Objects
By default, all attributes of a newly created object have NULL values.
After initializing attribute data, the user must change the corresponding NULL status of
each attribute to non-NULL.
It is possible to have attributes set to non-NULL values when an object is created. This
is accomplished by setting the OCI_ATTR_OBJECT_NEWNOTNULL attribute of the environment
handle to TRUE using OCIAttrSet(). This mode can later be turned off by setting the
attribute to FALSE.
If OCI_ATTR_OBJECT_NEWNOTNULL is set to TRUE, then OCIObjectNew() creates a non-NULL
object. The attributes of the object have the default values described in Table 19-4,
and the corresponding NULL indicators are set to NOT NULL.

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Table 19-4

Attribute Values for New Objects

Attribute Type

Default Value

REF

If an object has a REF attribute, the user must set it to a valid REF
before flushing the object or an error is returned

DATE

The earliest possible date that Oracle Database allows, which is
midnight, 01-JAN-4712 BCE (equivalent to Julian day 1)

ANSI DATE

The earliest possible date that Oracle Database allows, 01JAN-4712 BCE (equivalent to Julian day 1)

TIMESTAMP

The earliest possible date and time that Oracle Database allows,
which is midnight, 01-JAN-4712 BCE (equivalent to Julian day 1)

TIMESTAMP WITH TIME ZONE

TIMESTAMP WITH LOCAL
TIME ZONE
INTERVAL YEAR TO MONTH
INTERVAL DAY TO SECOND

The earliest possible date and time that Oracle Database allows,
which is midnight, 01-JAN-4712 BCE (equivalent to Julian day 1)
at UTC (0:0) time zone
The earliest possible date and time that Oracle Database allows,
which is midnight, 01-JAN-4712 BCE (equivalent to Julian day 1)
at UTC (0:0) time zone
INTERVAL '0-0' YEAR TO MONTH
INTERVAL '0 0:0:0' DAY TO SECOND

FLOAT

0

NUMBER

0

DECIMAL

0

RAW

Raw data with length set to 0. Note: the default value for a RAW
attribute is the same as that for a NULL RAW attribute.

VARCHAR2, NVARCHAR2

OCIString with 0 length and first char set to NULL. The default
value is the same as that of a NULL string attribute.

CHAR, NCHAR

OCIString with 0 length and first char set to NULL. The default
value is the same as that of a null string attribute.

VARCHAR

OCIString with 0 length and first char set to NULL. The default
value is the same as that of a null string attribute.

VARRAY

Collection with 0 elements

NESTED TABLE

Table with 0 elements

CLOB, NCLOB

Empty CLOB

BLOB

Empty BLOB

BFILE

The user must initialize the BFILE to a valid value by setting the
directory object and file name.

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See Also:
•

OCIAttrSet()

•

OCIObjectNew()

19.3.16 About Freeing and Copying Objects
Use OCIObjectFree() to free memory allocated by OCIObjectNew().
An object instance can have attributes that are pointers to additional memory
(secondary memory chunks).
Freeing an object deallocates all the memory allocated for the object, including the
associated NULL indicator structure and any secondary memory chunks. You must
neither explicitly free the secondary memory chunks nor reassign the pointers. Doing
so can result in memory leaks and memory corruption. This procedure deletes a
transient, but not a persistent, object before its lifetime expires. An application should
use OCIObjectMarkDelete() to delete a persistent object.
An application can copy one instance to another instance of the same type using
OCIObjectCopy().

See Also:
•

Memory Layout of an Instance

•

OCI Navigational and Type Functions

•

OCIObjectNew()

•

OCIObjectFree()

•

OCIObjectMarkDelete()

•

OCIObjectCopy()

19.3.17 Object Reference and Type Reference
The object extensions to OCI provide the application with the flexibility to access the
contents of objects using their pointers or their references.
OCI provides the function OCIObjectGetObjectRef() to return a reference to an object
when given the object's pointer.
For applications that also want to access the type information of objects, OCI provides
the function OCIObjectGetProperty() to return a reference to an object's type descriptor
object (TDO), when given a pointer to the object.

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When a persistent object based on an object table with system-generated object
identifiers (OIDs) is created, a reference to this object may be immediately obtained by
using OCIObjectGetObjectRef(). But when a persistent object is based on an object
view or on an object table with primary-key-based OIDs, all attributes belonging to the
primary key must first be set before a reference can be obtained.

See Also:
•

OCIObjectGetObjectRef()

•

OCIObjectGetProperty()

•

OCIObjectGetObjectRef()

19.3.18 Create Objects Based on Object Views and Object Tables
with Primary-Key-Based OIDs
Applications can use the OCIObjectNew() call to create objects, which are based on
object views, or on object tables with primary-key-based object identifiers (OIDs).
Because object identifiers of such views and tables are based on attribute values,
applications must then use OCIObjectSetAttr() to set all attributes belonging to the
primary key. Once the attribute values have been set, applications can obtain an
object reference based on the attribute value by calling OCIObjectGetObjectRef().
This process involves the following steps:
1.

Pin the object view or object table on which the new object is to be based.

2.

Create a new object using OCIObjectNew(), passing in the handle to the table or
view obtained by the pin operation in Step 1.

3.

Use OCIObjectSetAttr() to fill in the necessary values for the object attributes.
These must include those attributes that make up the user-defined object identifier
for the object table or object view.

4.

Use OCIObjectNew() to allocate an object reference, passing in the handle to the
table or view obtained by the pin operation in Step 1.

5.

Use OCIObjectGetObjectRef() to obtain the primary-key-based reference to the
object, if necessary. If desired, return to Step 2 to create more objects.

6.

Flush the newly created objects to the server.

Example 19-7

Creating a New Object for an Object View

void object_view_new ()
{
void
*table;
OCIRef *pkref;
void
*object;
OCIType *emptdo;
...
/* Set up the service context, error handle and so on.. */
...
/* Pin the object view */
OCIObjectPinTable(envp,errorp,svctx, "HR", strlen("HR"), "EMP_VIEW",

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strlen("EMP_VIEW"),(void *) 0, OCI_DURATION_SESSION, (void **) &table);
/* Create a new object instance */
OCIObjectNew(envp, errorp, svctx, OCI_TYPECODE_OBJECT,(OCIType *)emptdo, table,
OCI_DURATION_SESSION,FALSE,&object);
/* Populate the attributes of "object" */
OCIObjectSetAttr(...);
...
/* Allocate an object reference */
OCIObjectNew(envp, errorp, svctx, OCI_TYPECODE_REF, (OCIType *)0, (void *)0,
OCI_DURATION_SESSION,TRUE,&pkref);
/* Get the reference using OCIObjectGetObjectRef */
OCIObjectGetObjectRef(envp,errorp,object,pkref);
...
/* Flush new objects to server */
...
} /* end function */

Example 19-7 shows how this process might be implemented to create a new object
for the emp_view object view in the HR schema.

See Also:
•

OCIObjectNew()

•

OCIObjectSetAttr()

•

OCIObjectGetObjectRef()

19.3.19 Error Handling in Object Applications
Is like any other OCI application.
Error handling in OCI applications is the same whether or not the application uses
objects.

See Also:
Error Handling in OCI for more information about function return codes and
error messages

19.4 About Type Inheritance
Type inheritance of objects has many similarities to inheritance in C++ and Java.
You can create an object type as a subtype of an existing object type. The subtype is
said to inherit all the attributes and methods (member functions and procedures) of the
supertype, which is the original type. Only single inheritance is supported; an object
cannot have more than one supertype. The subtype can add new attributes and
methods to the ones it inherits. It can also override (redefine the implementation) of

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any of its inherited methods. A subtype is said to extend (that is, inherit from) its
supertype.
As an example, a type Person_t can have a subtype Student_t and a subtype
Employee_t. In turn, Student_t can have its own subtype, PartTimeStudent_t. A type
declaration must have the flag NOT FINAL so that it can have subtypes. The default is
FINAL, which means that the type can have no subtypes.
All types discussed so far in this chapter are FINAL. All types in applications developed
before Oracle Database Release 9.0 are FINAL. A type that is FINAL can be altered to
be NOT FINAL. A NOT FINAL type with no subtypes can be altered to be FINAL. Person_t is
declared as NOT FINAL for our example:
CREATE TYPE Person_t AS OBJECT
( ssn NUMBER,
name VARCHAR2(30),
address VARCHAR2(100)) NOT FINAL;

A subtype inherits all the attributes and methods declared in its supertype. It can also
declare new attributes and methods, which must have different names than those of
the supertype. The keyword UNDER identifies the supertype, like this:
CREATE TYPE Student_t UNDER Person_t
( deptid NUMBER,
major VARCHAR2(30)) NOT FINAL;

The newly declared attributes deptid and major belong to the subtype Student_t. The
subtype Employee_t is declared as, for example:
CREATE TYPE Employee_t UNDER Person_t
( empid NUMBER,
mgr VARCHAR2(30));

See OTT Support for Type Inheritance for the resulting structs generated by OTT for
this example.
This subtype Student_t can have its own subtype, such as PartTimeStudent_t:
CREATE TYPE PartTimeStudent_t UNDER Student_t
( numhours NUMBER) ;

This section includes the following topics:
•

Substitutability

•

NOT INSTANTIABLE Types and Methods

•

OCI Support for Type Inheritance

•

OTT Support for Type Inheritance

See Also:
Oracle Database Object-Relational Developer's Guide for a more complete
discussion about type inheritance

19-36

Chapter 19

About Type Inheritance

19.4.1 Substitutability
Object type attributes and collection element types are substitutable.
The benefits of polymorphism derive partially from the property substitutability.
Substitutability allows a value of some subtype to be used by code originally written for
the supertype, without any specific knowledge of the subtype being needed in
advance. The subtype value behaves to the surrounding code, just like a value of the
supertype would, even if it perhaps uses different mechanisms within its
specializations of methods.
Instance substitutability refers to the ability to use an object value of a subtype in a
context declared in terms of a supertype. REF substitutability refers to the ability to use
a REF to a subtype in a context declared in terms of a REF to a supertype.
REF type attributes are substitutable; that is, an attribute defined as REF T can hold a REF
to an instance of T or any of its subtypes.

Object type attributes are substitutable; an attribute defined to be of (an object) type T
can hold an instance of T or any of its subtypes.
Collection element types are substitutable; if you define a collection of elements of
type T, it can hold instances of type T and any of its subtypes. Here is an example of
object attribute substitutability:
CREATE TYPE Book_t AS OBJECT
( title VARCHAR2(30),
author Person_t
/* substitutable */);

Thus, a Book_t instance can be created by specifying a title string and a Person_t (or
any subtype of Person_t) instance:
Book_t('My Oracle Experience',
Employee_t(12345, 'Joe', 'SF', 1111, NULL))

19.4.2 NOT INSTANTIABLE Types and Methods
A type can be declared to be NOT INSTANTIABLE, which means that there is no
constructor (default or user-defined) for the type.
Thus, it is not possible to construct instances of this type. The typical usage would be
to define instantiable subtypes for such a type. Here is how this property is used:
CREATE TYPE Address_t AS OBJECT(...) NOT INSTANTIABLE NOT FINAL;
CREATE TYPE USAddress_t UNDER Address_t(...);
CREATE TYPE IntlAddress_t UNDER Address_t(...);

A method of a type can be declared to be NOT INSTANTIABLE. Declaring a method as NOT
INSTANTIABLE means that the type is not providing an implementation for that method.
Further, a type that contains any NOT INSTANTIABLE methods must necessarily be
declared as NOT INSTANTIABLE. For example:
CREATE TYPE T AS OBJECT
(
x NUMBER,
NOT INSTANTIABLE MEMBER FUNCTION func1() RETURN NUMBER
) NOT INSTANTIABLE NOT FINAL;

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Chapter 19

About Type Inheritance

A subtype of a NOT INSTANTIABLE type can override any of the NOT INSTANTIABLE methods
of the supertype and provide concrete implementations. If there are any NOT
INSTANTIABLE methods remaining, the subtype must also necessarily be declared as
NOT INSTANTIABLE.
A NOT INSTANTIABLE subtype can be defined under an instantiable supertype. Declaring
a NOT INSTANTIABLE type to be FINAL is not useful and is not allowed.

19.4.3 OCI Support for Type Inheritance
Lists the calls that support type inheritance.
The following calls support type inheritance:
•

OCIDescribeAny()

•

Bind and Define Functions

•

OCIObjectGetTypeRef()

•

OCIObjectCopy()

•

OCICollAssignElem()

•

OCICollAppend()

•

OCICollGetElem()

19.4.3.1 OCIDescribeAny()
The OCIDescribeAny() function provides information specific to inherited types.
Additional attributes have been added for the properties of inherited types. For
example, you can get the supertype of a type.

See Also:
•

Table 8-7 and Table 8-9 for attributes that OCIDescribeAny() can use to
describe existing schema and subschema objects

•

OCIDescribeAny()

19.4.3.2 Bind and Define Functions
OCI bind functions support REF, instance, and collection element substitutability
(subtype instances can be passed in where supertype is expected).
There are no changes to the OCI bind interface, because all type checking and
conversions are done on the server side.
OCI define functions also support substitutability (subtype instances can be fetched
into define variables declared to hold the supertype). However, this might require the
system to resize the memory to hold the subtype instance.

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Chapter 19

About Type Inheritance

Note:
The client program must use objects that are allocated out of the object
cache (and are thus resizable) in such scenarios.

The client should not use a struct (allocated on the stack) as the define variable if the
value is potentially polymorphic.

See Also:
Object-Relational Data Types in OCI for details of the bind and define
processes

19.4.3.3 OCIObjectGetTypeRef()
The OCIObjectGetTypeRef() function returns the REF of the TDO of the most specific
type of the input object.
This operation returns an error if the user does not have privileges on the most specific
type.

See Also:
OCIObjectGetTypeRef()

19.4.3.4 OCIObjectCopy()
The OCIObjectCopy() function copies the contents of the source instance to the target
instance.
The source and target instances must be of the same type. It is not possible to copy
between a supertype and a subtype.
Similarly, the tdo argument must describe the same object type as the source and
target objects, and must not refer to a subtype or supertype of the source and target
objects.

See Also:
OCIObjectCopy()

19.4.3.5 OCICollAssignElem()
The input element can be an instance of the subtype of the declared type.

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Chapter 19

About Type Inheritance

If the collection is of type Person_t, you can use the OCICollAssignElem() function to
assign an Employee_t instance as an element of the collection.

See Also:
OCICollAssignElem()

19.4.3.6 OCICollAppend()
The input element can be an instance of the subtype of the declared type.
If the collection is of type Person_t, you can use the OCICollAppend() function to append
an Employee_t instance to the collection.

See Also:
OCICollAppend()

19.4.3.7 OCICollGetElem()
The collection element returned could be an instance of the subtype of the declared
type.
If the collection is of type Person_t, you can use the OCICollGetElem() function to get a
pointer to an element, such as an Employee_t instance, in this collection.

See Also:
OCICollGetElem()

19.4.4 OTT Support for Type Inheritance
The Object Type Translator (OTT) supports type inheritance of objects by declaring
first the inherited attributes in an encapsulated struct called "_super", followed by the
new declared attributes.
This is done because C does not support type inheritance.

See Also:
OTT Support for Type Inheritance for an example and discussion

19-40

Chapter 19

About Type Evolution

19.5 About Type Evolution
Adding, dropping, and modifying type attributes are supported. This concept is known
as type evolution.
It is discussed in the Oracle Database Object-Relational Developer's Guide.
OCIDescribeAny() returns information about the latest version of the requested type if
the type of the input object is OCI_OTYPE_NAME, and the type of the described object is
OCI_PTYPE_TYPE, that is, if the name input to OCIDescribeAny() is a type name.

See Also:
•

OCITypeArrayByName() and OCITypeByName(). To access type
information, use these functions and OCIDescribeAny()

•

Type Evolution and the Object Cache for a discussion of the effect of
type evolution on the object cache

•

OCIDescribeAny()

19-41

20
Object-Relational Data Types in OCI
This chapter describes the purpose and structure of each of the data types that can be
manipulated by the OCI data type mapping and manipulation functions.
This chapter also summarizes the different function groups giving lists of available
functions and their purposes. In addition, provides information about how to use these
data types in bind and define operations within an OCI application.
This chapter contains these topics:
•

Overview of OCI Functions for Objects

•

About Mapping Oracle Data Types to C

•

About Manipulating C Data Types with OCI

•

Date (OCIDate)

•

Datetime and Interval (OCIDateTime, OCIInterval)

•

Number (OCINumber)

•

Fixed or Variable-Length String (OCIString)

•

Raw (OCIRaw)

•

Collections (OCITable, OCIArray, OCIColl, OCIIter)

•

About Multilevel Collection Types

•

REF (OCIRef)

•

Object Type Information Storage and Access

•

AnyType, AnyData, and AnyDataSet Interfaces

•

About Binding Named Data Types

•

About Defining Named Data Types

•

About Binding and Defining Oracle C Data Types

•

SQLT_NTY Bind and Define Examples

20.1 Overview of OCI Functions for Objects
The OCI data type mapping and manipulation functions provide the ability to
manipulate instances of predefined Oracle C data types.
These data types are used to represent the attributes of user-defined data types,
including object types in Oracle Database.
Each group of functions within OCI is distinguished by a particular naming convention.
The data type mapping and manipulation functions, for example, can be easily
recognized because the function names start with the prefix OCI, followed by the
name of a data type, as in OCIDateFromText() and OCIRawSize(). As will be explained

20-1

Chapter 20

About Mapping Oracle Data Types to C

later, the names can be further subdivided into function groups that operate on a
particular type of data.
The predefined Oracle C types on which these functions operate are also
distinguished by names that begin with the prefix OCI, as in OCIDate or OCIString.
The data type mapping and manipulation functions are used when an application must
manipulate, bind, or define attributes of objects that are stored in an Oracle database,
or that have been retrieved by a SQL query. Retrieved objects are stored in the clientside object cache.
The OCI client must allocate a descriptor before performing a bind or define operation.
OCIStmtExecute() and OCIStmtFetch2() cannot allocate the memory for the descriptors if
they are not allocated by OCIDescriptorAlloc().
These functions are valid only when an OCI application is running in object mode. For
information about initializing OCI in object mode and creating an OCI application that
accesses and manipulates objects, see About Initializing the Environment and the
Object Cache.

Note:
Operations on object types such as OCIDate, allow the address of the result to
be the same as that of one of the operands.

See Also:
•

OCIDateFromText()

•

OCIRawSize()

•

Object Advanced Topics in OCI for more information about retrieved
objects being stored in the client-side object cache

•

OCIStmtExecute()

•

OCIStmtFetch2()

•

OCIDescriptorAlloc()

•

Oracle Database Object-Relational Developer's Guide for detailed
information about object types, attributes, and collection data types

20.2 About Mapping Oracle Data Types to C
Oracle provides a rich set of predefined data types with which you can create tables
and specify user-defined data types (including object types).
Object types extend the functionality of Oracle Database by allowing you to create
data types that precisely model the types of data with which they work. This can
provide increased efficiency and ease-of-use for programmers who are accessing the
data.
You can use NCHAR and NVARCHAR2 as attributes in objects and map to OCIString * in C.

20-2

Chapter 20

About Mapping Oracle Data Types to C

Database tables and object types are based upon the data types supplied by Oracle.
These tables and types are created with SQL statements and stored using a specific
set of Oracle internal data types, like VARCHAR2 or NUMBER. For example, the following
SQL statements create a user-defined address data type and an object table to store
instances of that type:
CREATE TYPE address AS OBJECT
(street1
varchar2(50),
street2
varchar2(50),
city
varchar2(30),
state
char(2),
zip
number(5));
CREATE TABLE address_table OF address;

The new address type could also be used to create a regular table with an object
column:
CREATE TABLE employees
(name
varchar2(30),
birthday
date,
home_addr
address);

An OCI application can manipulate information in the name and birthday columns of the
employees table using straightforward bind and define operations in association with
SQL statements. Accessing information stored as attributes of objects requires some
extra steps.
The OCI application first needs a way to represent the objects in a C language format.
This is accomplished by using the Object Type Translator (OTT) to generate C struct
representations of user-defined types. The elements of these structs have data types
that represent C language mappings of Oracle data types.
An additional C type, OCIInd, is used to represent null indicator information
corresponding to attributes of object types.
This section includes the following topic: OCI Type Mapping Methodology.

See Also:
•

Table 24-1 for the available Oracle types and their C mappings you can
use as object attribute types

•

Using the Object Type Translator with OCI for more information and
examples about using OTT

20.2.1 OCI Type Mapping Methodology
Oracle followed a distinct design philosophy when specifying the mappings of Oracle
predefined types.
The current system has the following benefits and advantages:
•

The actual representation of data types like OCINumber is opaque to client
applications, and the data types are manipulated with a set of predefined

20-3

Chapter 20

About Manipulating C Data Types with OCI

functions. This allows the internal representation to change to accommodate future
enhancements without breaking user code.
•

The implementation is consistent with object-oriented paradigms in which class
implementation is hidden and only the required operations are exposed.

•

This implementation can have advantages for programmers. Consider writing a C
program to manipulate Oracle number variables without losing the accuracy
provided by Oracle numbers. To do this operation in Oracle Database Release 7,
you would have had to issue a "SELECT ... FROM DUAL" statement. In later releases,
this is accomplished by invoking the OCINumber*() functions.

20.3 About Manipulating C Data Types with OCI
Shows how you can manipulate C data types with OCI and shows the various function
prefixes, along with example function names and the data types on which the functions
operate.
In an OCI application, the manipulation of data may be as simple as adding together
two integer variables and storing the result in a third variable:
int
int_1, int_2, sum;
...
/* some initialization occurs */
...
sum = int_1 + int_2;

The C language provides a set of predefined operations on simple types such as
integer. However, the C data types listed in Table 24-1 are not simple C primitives.
Types such as OCIString and OCINumber are actually structs with a specific Oracledefined internal structure. It is not possible to simply add together two OCINumbers and
store the value in the third.
The following is not valid:
OCINumber
num_1, num_2, sum;
...
/* some initialization occurs */
...
sum = num_1 + num_2;
/* NOT A VALID OPERATION */

The OCI data type mapping and manipulation functions are provided to enable you to
perform operations on these new data types. For example, the preceding addition of
OCINumbers could be accomplished as follows, using the OCINumberAdd() function:
OCINumber
num_1, num_2, sum;
...
/* some initialization occurs */
...
OCINumberAdd(errhp, &num_1, &num_2, &sum): /* errhp is error handle */

OCI provides functions to operate on each of the new data types. The names of the
functions provide information about the data types on which they operate. The first
three letters, OCI, indicate that the function is part of OCI. The next part of the name
indicates the data type on which the function operates. Table 20-1 shows the various
function prefixes, along with example function names and the data types on which the
functions operate.

20-4

Chapter 20

Date (OCIDate)

Table 20-1

Function Prefix Examples

Function Prefix

Example

Operates on

OCIColl

OCICollGetElem()

OCIColl, OCIIter, OCITable,
OCIArray

OCIDate

OCIDateDaysBetween()

OCIDate

OCIDateTime

OCIDateTimeSubtract()

OCIDate, OCIDateTime

OCIInterval

OCIIntervalToText()

OCIInterval

OCIIter

OCIIterInit()

OCIIter

OCINumber

OCINumberAdd()

OCINumber

OCIRaw

OCIRawResize()

OCIRaw *

OCIRef

OCIRefAssign()

OCIRef *

OCIString

OCIStringSize()

OCIString *

OCITable

OCITableLast()

OCITable *

The structure of each of the data types is described later in this chapter, along with a
list of the functions that manipulate that type.
This section includes the following topic: Precision of Oracle Number Operations.

20.3.1 Precision of Oracle Number Operations
Oracle numbers have a precision of 38 decimal digits.
All Oracle number operations are accurate to the full precision, with the following
exceptions:
•

Inverse trigonometric functions are accurate to 28 decimal digits.

•

Other transcendental functions, including trigonometric functions, are accurate to
approximately 37 decimal digits.

•

Conversions to and from native floating-point types have the precision of the
relevant floating-point type, not to exceed 38 decimal digits.

20.4 Date (OCIDate)
The Oracle date format is mapped in C by the OCIDate type, which is an opaque C
struct. Elements of the struct represent the year, month, day, hour, minute, and
second of the date.

20-5

Chapter 20

Date (OCIDate)

The specific elements can be set and retrieved using the appropriate OCI functions.
The OCIDate data type can be bound or defined directly using the external typecode
SQLT_ODT in the bind or define call.
Unless otherwise specified, the term date in these function calls refers to a value of
type OCIDate.

See Also:
OCI Data Type Mapping and Manipulation Functions for the prototypes and
descriptions of all the functions

This section includes the following topic: Date Example.

20.4.1 Date Example
Shows how to manipulate an attribute of type OCIDate using OCI calls.
Example 20-1 provides examples of how to manipulate an attribute of type OCIDate
using OCI calls. For this example, assume that OCIEnv and OCIError have been
initialized.
The output is:
For: FRIDAY , OCTOBER 05, 1990
The last day of the month is: WEDNESDAY, OCTOBER 31, 1990
The next Wednesday is: WEDNESDAY, OCTOBER 10, 1990

Example 20-1

Manipulating an Attribute of Type OCIDate

#define FMT "DAY, MONTH DD, YYYY"
#define LANG "American"
struct person
{
OCIDate start_date;
};
typedef struct person person;
OCIError *err;
person *tim;
sword status;
/* error status */
uword invalid;
OCIDate last_day, next_day;
text buf[100], last_day_buf[100], next_day_buf[100];
ub4 buflen = sizeof(buf);
/*
/*
/*
/*

Pin tim person object in the object cache. */
For this example, assume that
tim is pointing to the pinned object. */
set the start date of tim */

OCIDateSetTime(&tim->start_date,8,0,0);
OCIDateSetDate(&tim->start_date,1990,10,5);
/* check if the date is valid */
if (OCIDateCheck(err, &tim->start_date, &invalid) != OCI_SUCCESS)

20-6

Chapter 20

Datetime and Interval (OCIDateTime, OCIInterval)

/* error handling code */
if (invalid)
/* error handling code */
/* get the last day of start_date's month */
if (OCIDateLastDay(err, &tim->start_date, &last_day) != OCI_SUCCESS)
/* error handling code */
/* get date of next named day */
if (OCIDateNextDay(err, &tim->start_date, "Wednesday",
strlen("Wednesday"),
&next_day) != OCI_SUCCESS)
/* error handling code */
/* convert dates to strings and print the information */
/* first convert the date itself*/
buflen = sizeof(buf);
if (OCIDateToText(err, &tim->start_date, FMT, sizeof(FMT)-1, LANG,
sizeof(LANG)-1,
&buflen, buf) != OCI_SUCCESS)
/* error handling code */
/* now the last day of the month */
buflen = sizeof(last_day_buf);
if (OCIDateToText(err, &last_day, FMT, sizeof(FMT)-1, LANG,
&buflen, last_day_buf) != OCI_SUCCESS)
/* error handling code */

sizeof(LANG)-1,

/* now the first Wednesday after this date */
buflen = sizeof(next_day_buf);
if (OCIDateToText(err, &next_day, FMT, sizeof(FMT)-1, LANG,
sizeof(LANG)-1, &buflen, next_day_buf) != OCI_SUCCESS)
/* error handling code */
/* print the information */
printf("For: %s\n", buf);
printf("The last day of the month is: %s\n", last_day_buf);
printf("The next Wednesday is: %s\n", next_day_buf);

See Also:
•

OCI Environment Initialization for information about initializing OCIEnv and
OCIError

•

Object Cache Operations for information about pinning.

20.5 Datetime and Interval (OCIDateTime, OCIInterval)
The OCIDateTime data type is an opaque structure used to represent Oracle time-stamp
data types (TIMESTAMP, TIMESTAMP WITH TIME ZONE, TIMESTAMP WITH LOCAL TIME ZONE) and the
ANSI DATE data type.
You can set or retrieve the data in these types (that is, year, day, fractional second)
using the appropriate OCI functions.
The OCIInterval data type is also an opaque structure and is used to represent Oracle
interval data types (INTERVAL YEAR TO MONTH, INTERVAL DAY TO SECOND).

20-7

Chapter 20

Datetime and Interval (OCIDateTime, OCIInterval)

You can bind and define OCIDateTime and OCIInterval data using the following external
typecodes shown in Table 20-2 in the bind or define call.
Table 20-2

Binding and Defining Datetime and Interval Data Types

OCI Data Type

Type of Data

External Typecode for Binding/
Defining

OCIDateTime

ANSI DATE

SQLT_DATE

OCIDateTime

TIMESTAMP

SQLT_TIMESTAMP

OCIDateTime

TIMESTAMP WITH
TIME ZONE

SQLT_TIMESTAMP_TZ

OCIDateTime

TIMESTAMP WITH
LOCAL TIME ZONE

SQLT_TIMESTAMP_LTZ

OCIInterval

INTERVAL YEAR TO
MONTH

SQLT_INTERVAL_YM

OCIInterval

INTERVAL DAY TO
SECOND

SQLT_INTERVAL_DS

In general, functions that operate on OCIDateTime data are also valid for OCIDate data.
This section includes the following topics:
•

About Datetime Functions

•

Datetime Example

•

About Interval Functions

See Also:
•

Table 20-3 and Table 20-4 for information about OCI functions that
operate on datetime and interval data

•

OCI Date, Datetime, and Interval Functions for more detailed information
about datetime and interval functions

20.5.1 About Datetime Functions
Lists and describes functions that operate on OCIDateTime values.
The following functions operate on OCIDateTime values. Some of these functions also
perform arithmetic operations on datetime and interval values. Some functions may
only work for certain datetime types. The possible types are:
•

SQLT_DATE - DATE

•

SQLT_TIMESTAMP - TIMESTAMP

•

SQLT_TIMESTAMP_TZ - TIMESTAMP WITH TIME ZONE

•

SQLT_TIMESTAMP_LTZ - TIMESTAMP WITH LOCAL TIME ZONE

20-8

Chapter 20

Datetime and Interval (OCIDateTime, OCIInterval)

See the individual function descriptions listed in Table 20-3 for more information about
input types that are valid for a particular function.
Table 20-3

Datetime Functions

Function

Purpose

OCIDateTimeAssign()

Performs datetime
assignment

OCIDateTimeCheck()

Checks if the given date is
valid

OCIDateTimeCompare()

Compares two datetime
values

OCIDateTimeConstruct()

Constructs a datetime
descriptor

OCIDateTimeConvert()

Converts one datetime
type to another

OCIDateTimeFromArray()

Converts an array
containing a date to an
OCIDateTime descriptor

OCIDateTimeFromText()

Converts the given string
to Oracle datetime type in
the OCIDateTime
descriptor, according to
the specified format

OCIDateTimeGetDate()

Gets the date (year,
month, day) portion of a
datetime value

OCIDateTimeGetTime()

Gets the time (hour,
minute, second, fractional
second) from datetime
value

OCIDateTimeGetTimeZoneName()

Gets the time zone name
portion of a datetime value

OCIDateTimeGetTimeZoneOffset()

Gets the time zone (hour,
minute) portion of a
datetime value

OCIDateTimeIntervalAdd()

Adds an interval to a
datetime to produce a
resulting datetime

OCIDateTimeIntervalSub()

Subtracts an interval from
a datetime and stores the
result in a datetime

OCIDateTimeSubtract()

Takes two datetimes as
input and stores their
difference in an interval

OCIDateTimeSysTimeStamp()

Gets the system current
date and time as a time
stamp with time zone

OCIDateTimeToArray()

Converts an OCIDateTime
descriptor to an array

20-9

Chapter 20

Datetime and Interval (OCIDateTime, OCIInterval)

Table 20-3

(Cont.) Datetime Functions

Function

Purpose

OCIDateTimeToText()

Converts the given date to
a string according to the
specified format

OCIDateZoneToZone()

Converts the date from
one time zone to another
time zone

20.5.2 Datetime Example
Shows how to use an OCIDateTime data type to select data from a TIMESTAMP WITH LOCAL
TIME ZONE column.
The code fragment in Example 20-2 shows how to use an OCIDateTime data type to
select data from a TIMESTAMP WITH LOCAL TIME ZONE column.
Example 20-2

Manipulating an Attribute of Type OCIDateTime

...
/* allocate the program variable for storing the data */
OCIDateTime *tstmpltz = (OCIDateTime *)NULL;
/* Col1 is a time stamp with local time zone column */
OraText *sqlstmt = (OraText *)"SELECT col1 FROM foo";
/* Allocate the descriptor (storage) for the data type */
status = OCIDescriptorAlloc(envhp,(void **)&tstmpltz, OCI_DTYPE_TIMESTAMP_LTZ,
0, (void **)0);
....
status = OCIStmtPrepare (stmthp, errhp, sqlstmt, (ub4)strlen ((char *)sqlstmt),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
/* specify the define buffer for col1 */
status = OCIDefineByPos(stmthp, &defnp, errhp, 1, &tstmpltz, sizeof(tstmpltz),
SQLT_TIMESTAMP_LTZ, 0, 0, 0, OCI_DEFAULT);
/* Execute and Fetch */
OCIStmtExecute(svchp, stmthp, errhp, 1, 0,(OCISnapshot *) NULL,
(OCISnapshot *)NULL, OCI_DEFAULT)
At this point tstmpltz contains a valid time stamp with local time zone data. You
can get the time zone name of the datetime data using:
status = OCIDateTimeGetTimeZoneName(envhp, errhp, tstmpltz, (ub1 *)buf,
(ub4 *)&buflen);
...

20.5.3 About Interval Functions
Lists and describes the interval functions.

20-10

Chapter 20

Datetime and Interval (OCIDateTime, OCIInterval)

The functions listed in Table 20-4 operate exclusively on interval data. In some cases
it is necessary to specify the type of interval involved. Possible types include:
•

SQLT_INTERVAL_YM - interval year to month

•

SQLT_INTERVAL_DS - interval day to second

See the individual function descriptions for more detailed information.
Table 20-4

Interval Functions

Function

Purpose

OCIIntervalAdd()

Adds two intervals to
produce a resulting
interval

OCIIntervalAssign()

Copies one interval to
another

OCIIntervalCheck()

Checks the validity of an
interval

OCIIntervalCompare()

Compares two intervals

OCIIntervalDivide()

Divides an interval by an
Oracle NUMBER to produce
an interval

OCIIntervalFromNumber()

Converts an Oracle
NUMBER to an interval

OCIIntervalFromText()

When given an interval
string, converts the
interval represented by
the string

OCIIntervalFromTZ()

Returns an interval when
given an input string of
time zone form

OCIIntervalGetDaySecond()

Gets values of day, hour,
minute, and second from
an interval

OCIIntervalGetYearMonth()

Gets year and month from
an interval

OCIIntervalMultiply()

Multiplies an interval by an
Oracle NUMBER to produce
an interval

OCIIntervalSetDaySecond()

Sets day, hour, minute,
and second in an interval

OCIIntervalSetYearMonth()

Sets year and month in an
interval

OCIIntervalSubtract()

Subtracts two intervals
and stores the result in an
interval

OCIIntervalToNumber()

Converts an interval to an
Oracle NUMBER

OCIIntervalToText()

When given an interval,
produces a string
representing the interval

20-11

Chapter 20

Number (OCINumber)

See Also:
OCI Date, Datetime, and Interval Functions for complete lists of the names
and purposes and more detailed information about these functions

20.6 Number (OCINumber)
The OCINumber data type is an opaque structure used to represent Oracle numeric data
types (NUMBER, FLOAT, DECIMAL, and so forth).
You can bind or define this type using the external typecode SQLT_VNU in the bind or
define call.
Unless otherwise specified, the term number in these functions refers to a value of
type OCINumber.
This section includes the following topic: OCINumber Examples.

See Also:
Table 28-11for the prototypes and descriptions for all the OCI NUMBER
functions

20.6.1 OCINumber Examples
Shows how to manipulate an attribute of type OCINumber, how to convert values in
OCINumber format returned from OCIDescribeAny() calls to unsigned integers, and how to
convert a numeric type returned from an OCIDescribeAny() call in OCINumber format,
such as OCI_ATTR_MAX or OCI_ATTR_MIN, to an unsigned C integer.
The code fragment in Example 20-3 shows how to manipulate an attribute of type
OCINumber. The code fragment in Example 20-4 shows how to convert values in
OCINumber format returned from OCIDescribeAny() calls to unsigned integers.

Example 20-4 shows how to convert a numeric type returned from an OCIDescribeAny()
call in OCINumber format, such as OCI_ATTR_MAX or OCI_ATTR_MIN, to an unsigned C
integer.
Example 20-3

Manipulating an Attribute of Type OCINumber

/* Example 1 */
struct person
{
OCINumber sal;
};
typedef struct person person;
OCIError *err;
person* steve;
person* scott;
person* jason;
OCINumber *stevesal;
OCINumber *scottsal;

20-12

Chapter 20

Number (OCINumber)

OCINumber *debsal;
sword status;
int
inum;
double dnum;
OCINumber ornum;
text buffer[21];
ub4
buflen;
sword result;
/* For this example, assume OCIEnv and OCIError are initialized. */
/* For this example, assume that steve, scott, and jason are pointing to
person objects that have been pinned in the object cache. */
stevesal = &steve->sal;
scottsal = &scott->sal;
debsal = &jason->sal;
/* initialize steve's salary to be $12,000 */
inum = 12000;
status = OCINumberFromInt(err, &inum, sizeof(inum), OCI_NUMBER_SIGNED,
stevesal);
if (status != OCI_SUCCESS) /* handle error from OCINumberFromInt */;
/* initialize scott's salary to be the same as steve's */
OCINumberAssign(err, stevesal, scottsal);
/* initialize jason's salary to be 20% more than steve's */
dnum = 1.2;
status = OCINumberFromReal(err, &dnum, sizeof(dnum), &ornum);
if (status != OCI_SUCCESS) /* handle error from OCINumberFromReal */;
status = OCINumberMul(err, stevesal, &ornum, debsal);
if (status != OCI_SUCCESS) /* handle error from OCINumberMul */;
/* give scott a 50% raise */
dnum = 1.5;
status = OCINumberFromReal(err, &dnum, sizeof(dnum), &ornum);
if (status != OCI_SUCCESS) /* handle error from OCINumberFromReal */;
status = OCINumberMul(err, scottsal, &ornum, scottsal);
if (status != OCI_SUCCESS) /* handle error from OCINumberMul */;
/* double steve's salary */
status = OCINumberAdd(err, stevesal, stevesal, stevesal);
if (status != OCI_SUCCESS) /* handle error from OCINumberAdd */;
/* get steve's salary in integer */
status = OCINumberToInt(err, stevesal, sizeof(inum), OCI_NUMBER_SIGNED, &inum);
if (status != OCI_SUCCESS) /* handle error from OCINumberToInt */;
/* inum is set to 24000 */
/* get jason's salary in double */
status = OCINumberToReal(err, debsal, sizeof(dnum), &dnum);
if (status != OCI_SUCCESS) /* handle error from OCINumberToReal */;
/* dnum is set to 14400 */
/* print scott's salary as DEM0001'8000.00 */
buflen = sizeof(buffer);
status = OCINumberToText(err, scottsal, (text *)"C0999G9999D99", 13,
(text *)"NLS_NUMERIC_CHARACTERS='.'' NLS_ISO_CURRENCY='Germany'",
54, &buflen, (text *)buffer);
if (status != OCI_SUCCESS) /* handle error from OCINumberToText */;
printf("scott's salary = %s\n", buffer);

20-13

Chapter 20

Fixed or Variable-Length String (OCIString)

/* compare steve and scott's salaries */
status = OCINumberCmp(err, stevesal, scottsal, &result);
if (status != OCI_SUCCESS) /* handle error from OCINumberCmp */;
/* result is positive */
/* read jason's new salary from string */
status = OCINumberFromText(err, (text *)"48'000.00", 9, (text
*)"99G999D99", 9,
(text *)"NLS_NUMERIC_CHARACTERS='.''", 27, debsal);
if (status != OCI_SUCCESS) /* handle error from OCINumberFromText */;
/* jason's salary is now 48000.00 */

Example 20-4 Converting Values in OCINumber Format Returned from
OCIDescribeAny() Calls to Unsigned Integers
/* Example 2 */
ub4 max_seq_val = 0;
ub1 *max_valp
= NULL;
ub4 max_val_size;
OCINumber max_val;
OCINumberSetZero(_errhp, &max_val);
OCIParam* parmdp = 0;
status = OCIAttrGet ((void *)_dschp, (ub4)OCI_HTYPE_DESCRIBE, &parmdp, 0,
(ub4)OCI_ATTR_PARAM, _errhp);
if (isError (status, _errhp))
{
return 0;
}
status = OCIAttrGet ((void *)parmdp, (ub4)OCI_DTYPE_PARAM, &max_valp,
&max_val_size, (ub4)OCI_ATTR_MAX, _errhp);
//create an OCINumber object from the ORACLE NUMBER FORMAT
max_val.OCINumberPart[0] = max_val_size; //set the length byte
memcpy(&max_val.OCINumberPart[1], max_valp, max_val_size); //copy the actual bytes
//now convert max_val to an unsigned C integer, max_seq_val
status = OCINumberToInt(_errhp, &max_val, sizeof(max_seq_val),
OCI_NUMBER_UNSIGNED, &max_seq_val);

20.7 Fixed or Variable-Length String (OCIString)
Fixed or variable-length string data is represented to C programs as an OCIString *.
The length of the string does not include the NULL character.
For binding and defining variables of type OCIString * use the external typecode
SQLT_VST.

This section includes the following topics:
•

About String Functions

•

String Example

See Also:
Table 28-16 for the prototypes and descriptions for all the string functions

20-14

Chapter 20

Fixed or Variable-Length String (OCIString)

20.7.1 About String Functions
Lists and describes functions that allow the C programmer to manipulate an instance
of a string.
Table 20-5 shows the functions that allow the C programmer to manipulate an
instance of a string.
Table 20-5

String Functions

Function

Purpose

OCIStringAllocSize()

Get allocated size of string
memory in code points
(Unicode) or bytes

OCIStringAssign()

Assign one string to another
string

OCIStringAssignText()

Assign the source text string
to the target string

OCIStringPtr()

Get a pointer to the text of a
given string

OCIStringResize()

Resize the memory of a
given string

OCIStringSize()

Get the size of a given string

20.7.2 String Example
Assigns a text string to a string, then gets a pointer to the string part of the string, and
the string size, and prints it out.
Example 20-5 assigns a text string to a string, then gets a pointer to the string part of
the string, and the string size, and prints it out.
Note the double indirection used in passing the vstring1 parameter in
OCIStringAssignText().

Example 20-5
OCIEnv
OCIError
OCIString
OCIString
text
text
sword

Manipulating an Attribute of Type OCIString

*envhp;
*errhp;
*vstring1 = (OCIString *)0;
*vstring2 = (OCIString *)0;
c_string[20];
*text_ptr;
status;

strcpy((char *)c_string, "hello world");
/* Assign a text string to an OCIString */
status = OCIStringAssignText(envhp, errhp, c_string,
(ub4)strlen((char *)c_string),&vstring1);
/* Memory for vstring1 is allocated as part of string assignment */
status = OCIStringAssignText(envhp, errhp, (text *)"hello again",
(ub4)strlen("This is a longer string."),&vstring1);
/* vstring1 is automatically resized to store the longer string */

20-15

Chapter 20

Raw (OCIRaw)

/* Get a pointer to the string part of vstring1 */
text_ptr = OCIStringPtr(envhp, vstring1);
/* text_ptr now points to "hello world" */
printf("%s\n", text_ptr);

See Also:
OCIStringAssignText()

20.8 Raw (OCIRaw)
Variable-length raw data is represented in C using the OCIRaw * data type.
For binding and defining variables of type OCIRaw *, use the external typecode
SQLT_LVB.

This section includes the following topics:
•

About Raw Functions

•

Raw Example

See Also:
Table 28-14 for the prototypes and descriptions for all the raw functions

20.8.1 About Raw Functions
Lists and describes the Raw functions.
Table 20-6 shows the functions that perform OCIRaw operations.
Table 20-6

Raw Functions

Function

Purpose

OCIRawAllocSize()

Get the allocated size of raw
memory in bytes

OCIRawAssignBytes()

Assign raw data (ub1 *) to
OCIRaw *

OCIRawAssignRaw()

Assign one OCIRaw * to
another

OCIRawPtr()

Get pointer to raw data

OCIRawResize()

Resize memory of variablelength raw data

OCIRawSize()

Get size of raw data

20-16

Chapter 20

Collections (OCITable, OCIArray, OCIColl, OCIIter)

20.8.2 Raw Example
Shows how to set up a raw data block and obtain a pointer to its data.
Example 20-6 shows how to set up a raw data block and obtain a pointer to its data.
Note the double indirection in the call to OCIRawAssignBytes().
Example 20-6

Manipulating an Attribute of Type OCIRaw

OCIEnv
*envhp;
OCIError
*errhp;
sword
status;
ub1
data_block[10000];
ub4
data_block_len = 10000;
OCIRaw
*raw1 = (OCIRaw *) 0;
ub1 *raw1_pointer;
/* Set up the RAW */
/* assume 'data_block' has been initialized */
status = OCIRawAssignBytes(envhp, errhp, data_block, data_block_len,
&raw1);
/* Get a pointer to the data part of the RAW */
raw1_pointer = OCIRawPtr(envhp, raw1);

See Also:
OCIRawAssignBytes()

20.9 Collections (OCITable, OCIArray, OCIColl, OCIIter)
Oracle Database provides two types of collections: variable-length arrays (varrays)
and nested tables. In C applications, varrays are represented as OCIArray *, and
nested tables are represented as OCITable *.
Both of these data types (along with OCIColl and OCIIter, described later) are opaque
structures.
A variety of generic collection functions enable you to manipulate collection data. You
can use these functions on both varrays and nested tables. In addition, there is a set
of functions specific to nested tables.
This section includes the following topics:
•

Generic Collection Functions

•

About Collection Data Manipulation Functions

•

About Collection Scanning Functions

•

Varray/Collection Iterator Example

•

About Nested Table Manipulation Functions

•

About Nested Table Manipulation Functions

20-17

Chapter 20

Collections (OCITable, OCIArray, OCIColl, OCIIter)

You can allocate an instance of a varray or nested table using OCIObjectNew() and free
it using OCIObjectFree().

See Also:
•

About Nested Table Manipulation Functions

•

OCIObjectNew()

•

OCIObjectFree()

•

OCI Collection and Iterator Functions for the prototypes and descriptions
for these functions

20.9.1 Generic Collection Functions
Oracle Database provides two types of collections: variable-length arrays (varrays)
and nested tables.
Both varrays and nested tables can be viewed as subtypes of a generic collection
type.
In C, a generic collection is represented as OCIColl *, a varray is represented as
OCIArray *, and a nested table is represented as OCITable *. Oracle provides a set of
functions to operate on generic collections (such as OCIColl *). These functions start
with the prefix OCIColl, as in OCICollGetElem(). The OCIColl*() functions can also be
called to operate on varrays and nested tables.
The generic collection functions are grouped into two main categories:
•

Manipulating varray or nested table data

•

Scanning through a collection with a collection iterator

The generic collection functions represent a complete set of functions for manipulating
varrays. Additional functions are provided to operate specifically on nested tables.
They are identified by the prefix OCITable, as in OCITableExists().

Note:
Indexes passed to collection functions are zero-based.

See Also:
•

OCITableExists()

•

About Nested Table Manipulation Functions

20-18

Chapter 20

Collections (OCITable, OCIArray, OCIColl, OCIIter)

20.9.2 About Collection Data Manipulation Functions
Lists and describes the collection data manipulation functions.
Table 20-7 shows the generic functions that manipulate collection data.
Table 20-7

Collection Functions

Function

Purpose

OCICollAppend()

Append an element to the end
of a collection

OCICollAssign()

Assign one collection to another

OCICollAssignElem()

Assign element at given index

OCICollGetElem()

Get pointer to an element when
given its index

OCICollGetElemArray()

Get array of elements from a
collection

OCICollIsLocator()

Indicate whether a collection is
locator-based or not

OCICollMax()

Get upper bound of collection

OCICollSize()

Get current size of collection

OCICollTrim()

Trim n elements from the end of
the collection

20.9.3 About Collection Scanning Functions
Lists and describes the collection scanning functions.
Table 20-8 shows the generic functions that enable you to scan collections with a
collection iterator. The iterator is of type OCIIter, and is created by first calling
OCIIterCreate().
Table 20-8

Collection Scanning Functions

Function

Purpose

OCIIterCreate()

Create an iterator to scan the
elements of a collection

OCIIterDelete()

Delete a collection iterator

OCIIterGetCurrent()

Get a pointer to the current
element pointed to by the
iterator

OCIIterInit()

Initialize an iterator to scan the
given collection

OCIIterNext()

Get a pointer to the next iterator
collection element

OCIIterPrev()

Get pointer to the previous
iterator collection element

20-19

Chapter 20

Collections (OCITable, OCIArray, OCIColl, OCIIter)

20.9.4 Varray/Collection Iterator Example
Shows how to create and use a collection iterator to scan through a varray.
Example 20-7 creates and uses a collection iterator to scan through a varray.
Example 20-7
OCIEnv
OCIError
text
sword
OCIArray
OCIString
OCIIter
boolean
void
OCIInd

Using Collection Data Manipulation Functions

*envhp;
*errhp;
*text_ptr;
status;
*clients;
*client_elem;
*iterator;
eoc;
*elem;
*elemind;

/* Assume envhp, errhp have been initialized */
/* Assume clients points to a varray */
/* Print the elements of clients */
/* To do this, create an iterator to scan the varray */
status = OCIIterCreate(envhp, errhp, clients, &iterator);
/* Get the first element of the clients varray */
printf("Clients' list:\n");
status = OCIIterNext(envhp, errhp, iterator, &elem,
(void **) &elemind, &eoc);
while (!eoc && (status == OCI_SUCCESS))
{
client_elem = *((OCIString **)elem);
/* client_elem points to the string */
/*
the element pointer type returned by OCIIterNext() through 'elem' is
the same as that of OCICollGetElem(). See OCICollGetElem() for
details. */
/*
client_elem points to an OCIString descriptor, so to print it out,
get a pointer to where the text begins
*/
text_ptr = OCIStringPtr(envhp, client_elem);
/*
text_ptr now points to the text part of the client OCIString, which
is a
NULL-terminated string
*/
printf(" %s\n", text_ptr);
status = OCIIterNext(envhp, errhp, iterator, &elem,
(void **)&elemind, &eoc);
}
if (status != OCI_SUCCESS)
{

20-20

Chapter 20

Collections (OCITable, OCIArray, OCIColl, OCIIter)

/* handle error */
}
/* destroy the iterator */
status = OCIIterDelete(envhp, errhp, &iterator);

20.9.5 About Nested Table Manipulation Functions
As its name implies, one table may be nested, or contained within another, as a
variable, attribute, parameter, or column.
Nested tables may have elements deleted by the OCITableDelete() function.
For example, suppose a table is created with 10 elements, and OCITableDelete() is
used to delete elements at index 0 through 4 and 9. The first existing element is now
element 5, and the last existing element is element 8.
As noted previously, the generic collection functions may be used to map to and
manipulate nested tables. In addition, Table 20-9 shows the functions that are specific
to nested tables. They should not be used on varrays.
Table 20-9

Nested Table Functions

Function

Purpose

OCITableDelete()

Delete an element at a given index

OCITableExists()

Test whether an element exists at
a given index

OCITableFirst()

Return the index for the first
existing element of a table

OCITableLast()

Return the index for the last
existing element of a table

OCITableNext()

Return the index for the next
existing element of a table

OCITablePrev()

Return the index for the previous
existing element of a table

OCITableSize()

Return the table size, not including
any deleted elements

This section includes the following topic: Nested Table Element Ordering.

20.9.5.1 Nested Table Element Ordering
When a nested table is fetched into the object cache, its elements are given a
transient ordering, numbered from zero to the number of elements, minus 1.
For example, a table with 40 elements would be numbered from 0 to 39.
You can use these position ordinals to fetch and assign the values of elements (for
example, fetch to element i, or assign to element j, where i and j are valid position
ordinals for the given table).
When the table is copied back to the database, its transient ordering is lost. Delete
operations may be performed against elements of the table. Delete operations create

20-21

Chapter 20

About Multilevel Collection Types

transient holes; that is, they do not change the position ordinals of the remaining table
elements.

20.9.6 Nested Table Locators
You can retrieve a locator to a nested table. A locator is like a handle to a collection
value, and it contains information about the database snapshot that exists at the time
of retrieval.
This snapshot information helps the database retrieve the correct instantiation of a
collection value at a later time when collection elements are fetched using the locator.
Unlike a LOB locator, a collection locator cannot be used to modify a collection
instance; it only locates the correct data. Using the locator enables an application to
return a handle to a nested table without having to retrieve the entire collection, which
may be quite large.
A user specifies when a table is created if a locator should be returned when a
collection column or attribute is fetched, using the RETURN AS LOCATOR specification.
You can use the OCICollIsLocator() function to determine whether a collection is
locator-based or not.

See Also:
•

OCICollIsLocator()

•

Oracle Database SQL Language Reference

20.10 About Multilevel Collection Types
The collection element itself can be directly or indirectly another collection type.
Multilevel collection type is the name given to such a top-level collection type.
Multilevel collections have the following characteristics:
•

They can be collections of other collection types.

•

They can be collections of objects with collection attributes.

•

They have no limit to the number of nesting levels.

•

They can contain any combination of varrays and nested tables.

•

They can be used as columns in tables.

OCI routines work with multilevel collections. The following routines can return in
parameter *elem an OCIColl*, which you can use in any of the collection routines:
•

OCICollGetElem()

•

OCIIterGetCurrent()

•

OCIIterNext()

•

OCIIterPrev()

20-22

Chapter 20

About Multilevel Collection Types

The following functions take a collection element and add it to an existing collection.
Parameter elem could be an OCIColl* if the element type is another collection:
•

OCICollAssignElem()

•

OCICollAppend()

This section includes the following topic: Multilevel Collection Type Example.

See Also:
•

OCICollGetElem()

•

OCIIterGetCurrent()

•

OCIIterNext()

•

OCIIterPrev()

•

OCICollAssignElem()

•

OCICollAppend()

20.10.1 Multilevel Collection Type Example
Shows how to iterate over the multilevel collection.
The following types and tables are used for Example 20-8.
type_1 (a NUMBER, b NUMBER)
NT1 TABLE OF type_1
NT2 TABLE OF NT1

The code fragment in Example 20-8 iterates over the multilevel collection.
Example 20-8

Using Multilevel Collection Data Manipulation Functions

...
OCIColl *outer_coll;
OCIColl *inner_coll;
OCIIter *itr1, *itr2;
Type_1 *type_1_instance;
..
/* assume that outer_coll points to a valid coll of type NT2 */
checkerr(errhp, OCIIterCreate(envhp, errhp, outer_coll, &itr1));
for(eoc = FALSE;!OCIIterNext(envhp, errhp, itr1, (void **) &elem,
(void **) &elem_null, &eoc) && !eoc;)
{
inner_coll = (OCIColl *)elem;
/* iterate over inner collection.. */
checkerr(errhp, OCIIterCreate(envhp, errhp, inner_coll, &itr2));
for(eoc2 = FALSE;!OCIIterNext(envhp, errhp, itr2, (void **)&elem2,
(void **) &elem2_null, &eoc2) && !eoc2;)
{
type_1_instance = (Type_1 *)elem2;
/* use the fields of type_1_instance */
}
/* close iterator over inner collection */
checkerr(errhp, OCIIterDelete(envhp, errhp, &itr2));

20-23

Chapter 20

REF (OCIRef)

}
/* close iterator over outer collection */
checkerr(errhp, OCIIterDelete(envhp, errhp, &itr1));
...

20.11 REF (OCIRef)
A REF (reference) is an identifier to an object.
It is an opaque structure that uniquely locates the object. An object may point to
another object by way of a REF.
In C applications, the REF is represented by OCIRef*.
This section includes the following topic:
•

About REF Manipulation Functions

•

REF Example

See Also:
Table 28-15 for the prototypes and descriptions for all the REF manipulation
functions

20.11.1 About REF Manipulation Functions
Lists and describes REF manipulation functions.
Table 20-10 shows the functions that perform REF operations.
Table 20-10

REF Manipulation Functions

Function

Purpose

OCIRefAssign()

Assign one REF to another

OCIRefClear()

Clear or nullify a REF

OCIRefFromHex()

Convert a hexadecimal string
to a REF

OCIRefHexSize()

Return the size of a
hexadecimal string
representation of REF

OCIRefIsEqual()

Compare two REFs for
equality

OCIRefIsNull()

Test whether a REF is NULL

OCIRefToHex()

Convert a REF to a
hexadecimal string

20-24

Chapter 20

Object Type Information Storage and Access

20.11.2 REF Example
Shows how to test two REFs for NULL, compares them for equality, and assigns one REF
to another.
Example 20-9 tests two REFs for NULL, compares them for equality, and assigns one REF
to another. Note the double indirection in the call to OCIRefAssign().
Example 20-9
OCIEnv
OCIError
sword
boolean
OCIRef

Using REF Manipulation Functions

*envhp;
*errhp;
status;
refs_equal;
*ref1, *ref2;

/* assume REFs have been initialized to point to valid objects */
/*Compare two REFs for equality */
refs_equal = OCIRefIsEqual(envhp, ref1, ref2);
printf("After first OCIRefIsEqual:\n");
if(refs_equal)
printf("REFs equal\n");
else
printf("REFs not equal\n");
/*Assign ref1 to ref2 */
status = OCIRefAssign (envhp, errhp, ref1, &ref2);
if(status != OCI_SUCCESS)
/*error handling*/
/*Compare the two REFs again for equality */
refs_equal = OCIRefIsEqual(envhp, ref1, ref2);
printf("After second OCIRefIsEqual:\n");
if(refs_equal)
printf("REFs equal\n");
else
printf("REFs not equal\n");

See Also:
OCIRefAssign()

20.12 Object Type Information Storage and Access
The OCI data types and type descriptors are discussed in this section.
This section includes the following topic: Descriptor Objects.

20.12.1 Descriptor Objects
Lists and describes the descriptor objects.

20-25

Chapter 20

AnyType, AnyData, and AnyDataSet Interfaces

When a given type is created with the CREATE TYPE statement, it is stored in the server
and associated with a type descriptor object (TDO). In addition, the database stores
descriptor objects for each data attribute of the type, each method of the type, each
parameter of each method, and the results returned by methods. Table 20-11 lists the
OCI data types associated with each type of descriptor object.
Table 20-11

Descriptor Objects

Information Type

OCI Data Type

Type

OCIType

Type Attributes Collection Elements
Method Parameters Method Results

OCITypeElem

Method

OCITypeMethod

Several OCI functions (including OCIBindObject() and OCIObjectNew()) require a TDO
as an input parameter. An application can obtain the TDO by calling OCITypeByName(),
which gets the type's TDO in an OCIType variable. Once you obtain the TDO, you can
pass it, as necessary, to other calls.

See Also:
•

OCIBindObject()

•

OCIObjectNew()

•

OCITypeByName()

20.13 AnyType, AnyData, and AnyDataSet Interfaces
The AnyType, AnyData, and AnyDataSet interfaces allow you to model self-descriptive
data.
You can store heterogeneous data types in the same column and query the type of
data in an application.
These definitions are used in the discussion in the following sections:
•

Persistent types. Types that are created using the SQL statement CREATE TYPE.
They are stored persistently in the database.

•

Transient types. Anonymous type descriptions that are not stored persistently in
the database. They are created by programs as needed. They are useful for
exchanging type information, if necessary, between various components of an
application in a dynamic fashion.

•

Self-descriptive data. Data encapsulating type information with its actual contents.
The OCIAnyData data type models such data in OCI. A data value of most SQL
types can be converted to an OCIAnyData that can then be converted back to the
old data value. The type SYS.ANYDATA models such data in SQL or PL/SQL.

•

Self-descriptive dataset. Encapsulation of a set of data instances (all of the same
type) along with their type description. They should all have the same type

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AnyType, AnyData, and AnyDataSet Interfaces

description. The OCIDataAnySet data type models this data in OCI. The type
SYS.ANYDATASET models such data in SQL or PL/SQL.
Interfaces are available in both OCI (C language) and in SQL and PL/SQL for
constructing and manipulating these type descriptions and self-descriptive data. The
following sections describe the relevant OCI interfaces.
This section includes the following topics:
•

About Type Interfaces

•

About OCIAnyData Interfaces

•

NCHAR Typecodes for OCIAnyData Functions

•

About OCIAnyDataSet Interfaces

See Also:
•

Persistent Objects, Transient Objects, and Values

•

Oracle Database SQL Language Reference for an overview in the
section about Oracle-supplied types

20.13.1 About Type Interfaces
You can use the type interfaces to construct named and anonymous transient object
types (structured with attributes) and collection types.
Use the OCITypeBeginCreate() call to begin type construction of transient object types
and collection types (the typecode parameter determines which one is being
constructed).
You must allocate a parameter handle using OCIDescriptorAlloc(). Subsequently, you
set type information (for attributes of an object type and for the collection element's
type) by using OCIAttrSet(). For object types, as shown in Example 20-10, use
OCITypeAddAttr() to add the attribute information to the type. After adding information
for the last attribute, you must call OCITypeEndCreate().
For collection types, as shown in Example 20-11, use OCITypeSetCollection() to set
the information on the collection element type. Subsequently, call OCITypeEndCreate()
to finish construction.
You can use the OCIDescribeAny() call to obtain the OCIType corresponding to a
persistent type.
Example 20-10

Using Type Interfaces to Construct Object Types

OCITypeBeginCreate( ...)
OCIDescriptorAlloc(...)
OCIAttrSet(...)
OCITypeAddAttr(...)
OCIAttrSet(...)
OCITypeAddAttr(...)
...
OCITypeEndCreate(...)

/* Begin Type Creation */

/* Add attribute 1 */
/* Add attribute 2 */
/* End Type Creation */

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Example 20-11

Using Type Interfaces to Construct Collection Types

OCITypeBeginCreate( ...)
OCIDescriptorAlloc(...)
OCIAttrSet(...)
OCITypeSetCollection(...)
OCITypeEndCreate(...)

/* Begin Type Creation */

/* Set information on collection element */
/* End Type Creation */

This section includes the following topics:
•

About Creating a Parameter Descriptor for OCIType Calls

•

About Obtaining the OCIType for Persistent Types

•

Type Access Calls

•

Extensions to OCIDescribeAny()

See Also:
•

OCITypeBeginCreate()

•

OCIDescriptorAlloc()

•

OCIAttrSet()

•

OCITypeAddAttr()

•

OCITypeEndCreate()

•

OCITypeSetCollection()

•

OCITypeEndCreate()

20.13.1.1 About Creating a Parameter Descriptor for OCIType Calls
You can use the OCIDescriptorAlloc() call to allocate an OCIParam (with the parent
handle being the environment handle).
Subsequently, you can call OCIAttrSet() with the following allowed attribute types to
set relevant type information:
•

OCI_ATTR_PRECISION

To set numeric precision. Pass a (ub1 *) attribute value to the buffer holding the
precision value.
•

OCI_ATTR_SCALE

To set numeric scale. Pass a (sb1 *) attribute value to the buffer that is holding the
scale value.
•

OCI_ATTR_CHARSET_ID

To set the character set ID for character types. Pass a (ub2 *) attribute value to the
buffer holding the char set ID.
•

OCI_ATTR_CHARSET_FORM

To set the character set form for character types. Pass a (ub1 *) attribute value to the
buffer holding the character set form value.

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•

OCI_ATTR_DATA_SIZE

Length of VARCHAR2, RAW, and so on. Pass a (ub2 *) attribute value to the buffer holding
the length.
•

OCI_ATTR_TYPECODE

To set typecode. Pass a (ub2 *) attribute value to the buffer holding the typecode. This
attribute must be set first.
•

OCI_ATTR_TDO

To set OCIType of an object or collection attribute. Pass an (OCIType *) attribute value
to the OCIType corresponding to the attribute. Ensure that the OCIType is pinned when
this OCIParam is used during AnyType construction. If it is a transient type attribute, its
allocation duration should be at least as much as the top-level OCIType being created.
Otherwise, an exception is returned.
•

For built-in types, the following typecodes are acceptable (permissible values for
OCI_ATTR_TYPECODE) for SQL type attributes:
OCI_TYPECODE_DATE, OCI_TYPECODE_NUMBER,
OCI_TYPECODE_VARCHAR, OCI_TYPECODE_RAW,
OCI_TYPECODE_CHAR, OCI_TYPECODE_VARCHAR2,
OCI_TYPECODE_VARCHAR, OCI_TYPECODE_BLOB,
OCI_TYPECODE_BFILE, OCI_TYPECODE_CLOB,
OCI_TYPECODE_TIMESTAMP, OCI_TYPECODE_TIMESTAMP_TZ,
OCI_TYPECODE_TIMESTAMP_LTZ,
OCI_TYPECODE_INTERVAL_YM, and OCI_TYPECODE_INTERVAL_DS.

•

If the attribute or collection element type is itself another transient type, set
OCI_ATTR_TYPECODE to OCI_TYPECODE_OBJECT or OCI_TYPECODE_REF (for REFs) or
OCI_TYPECODE_VARRAY or OCI_TYPECODE_TABLE and set the OCI_ATTR_TDO to the OCIType

corresponding to the transient type.
•

For user-defined type attributes, the permissible values for OCI_ATTR_TYPECODE are:
–

OCI_TYPECODE_OBJECT (for an Object Type)

–

OCI_TYPECODE_REF (for a REF type)

–

and OCI_TYPECODE_VARRAY or OCI_TYPECODE_TABLE (for collections)

The OCI_ATTR_TDO should be set in these cases to the appropriate user-defined
type's OCIType.

See Also:
•

OCIDescriptorAlloc()

•

OCIAttrSet()

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20.13.1.2 About Obtaining the OCIType for Persistent Types
You can use the OCIDescribeAny() call to obtain the OCIType corresponding to a
persistent type.
This is shown in the following example:
OCIDescribeAny(svchp, errhp. (void *)"HR.EMPLOYEES",
(ub4)strlen("HR.EMPLOYEES"),
(ub1)OCI_OTYPE_NAME, (ub1)OCI_DEFAULT, OCI_PTYPE_TYPE, dschp);

From the describe handle (dschp), you can use OCIAttrGet() calls to obtain the OCIType.

See Also:
•

OCIDescribeAny()

•

OCIAttrGet()

20.13.1.3 Type Access Calls
OCIDescribeAny() can be called with these transient type descriptions for a dynamic
description of the type.

The OCIType pointer can be passed directly to OCIDescribeAny() (with objtype set to
OCI_OTYPE_PTR). This provides a way to obtain attribute information by name and
position.

See Also:
OCIDescribeAny()

20.13.1.4 Extensions to OCIDescribeAny()
For transient types that represent built-in types (created with a built-in typecode), the
parameter handle that describes these types (which are of type OCI_PTYPE_TYPE) .
The parameter handle that describes these transient types supports the following extra
attributes:
•

OCI_ATTR_DATA_SIZE

•

OCI_ATTR_TYPECODE

•

OCI_ATTR_DATA_TYPE

•

OCI_ATTR_PRECISION

•

OCI_ATTR_SCALE

•

OCI_ATTR_CHARSET_ID

•

OCI_ATTR_CHARSET_FORM

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•

OCI_ATTR_LFPRECISION

•

OCI_ATTR_FSPRECISION

These attributes have the usual meanings they have while describing a type attribute.

Note:
These attributes are supported only for transient built-in types. The attributes
OCI_ATTR_IS_TRANSIENT_TYPE and OCI_ATTR_IS_PREDEFINED_TYPE are true for
these types. For persistent types, these attributes are supported only from
the parameter handle of the type's attributes (which are of type
OCI_PTYPE_TYPE_ATTR).

20.13.2 About OCIAnyData Interfaces
An OCIAnyData encapsulates type information and a data instance of that type (that is,
self-descriptive data).
An OCIAnyData can be created from any built-in or user-defined type instance by using
the OCIAnyDataConvert() call. This call does a conversion (cast) to an OCIAnyData.
Alternatively, object types and collection types can be constructed piece by piece (an
attribute at a time for object types or a collection element at a time) by calling
OCIAnyDataBeginCreate() with the type information (OCIType). Subsequently, you can
use OCIAnyDataAttrSet() for object types and use OCIAnyDataCollAddElem() for
collection types. Finally, use the OCIAnyDataEndCreate() call to finish the construction
process.
Subsequently, you can invoke the access routines. To convert (cast) an OCIAnyData to
the corresponding type instance, you can use OCIAnyDataAccess().
An OCIAnyData that is based on an object or collection type can also be accessed piece
by piece.
Special collection construction and access calls are provided for performance
improvement. You can use these calls to avoid unnecessary creation and copying of
the entire collection in memory, as shown in Example 20-12.
or
OCIAnyDataCollAddElem(...)

/* Element-wise construction for collections */

OCIAnyDataEndCreate(...)

/* End OCIAnyData Creation */

Example 20-12
Performance

Using Special Construction and Access Calls for Improved

OCIAnyDataConvert(...)

/* Cast a built-in or user-defined type instance
to an OCIAnyData in 1 call. */

OCIAnyDataBeginCreate(...)

/* Begin AnyData Creation */

OCIAnyDataAttrSet(...)

/* Attribute-wise construction for object types */

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See Also:
•

OCIAnyDataConvert()

•

OCIAnyDataBeginCreate()

•

OCIAnyDataAttrSet()

•

OCIAnyDataCollAddElem()

•

OCIAnyDataEndCreate()

•

OCIAnyDataAccess()

20.13.3 NCHAR Typecodes for OCIAnyData Functions
The function OCIAnyDataTypeCodeToSqlt() converts the OCITypeCode for an OCIAnyData
value to the SQLT code that corresponds to the representation of the value as
returned by the OCIAnyData API.
The following typecodes are used in the OCIAnyData functions only:
•

OCI_TYPECODE_NCHAR

•

OCI_TYPECODE_NVARCHAR2

•

OCI_TYPECODE_NCLOB

In calls to other functions, such as OCIDescribeAny(), these typecodes are not returned,
and you must use the character set form to determine if the data is NCHAR (if character
set form is SQLCS_NCHAR).
OCIAnyDataTypeCodeToSqlt() converts OCI_TYPECODE_CHAR and OCI_TYPECODE_VARCHAR2 to
the output values SQLT_VST (which corresponds to the OCIString mapping) with a
character set form of SQLCS_IMPLICIT. OCI_TYPECODE_NVARCHAR2 also returns SQLT_VST
(OCIString mapping is used by OCIAnyData API) with a character set form of
SQLCS_NCHAR.

See Also:
•

OCIDescribeAny()

•

OCIAnyDataTypeCodeToSqlt()

20.13.4 About OCIAnyDataSet Interfaces
An OCIAnyDataSet encapsulates type information and a set of instances of that type. To
begin the construction process, call OCIAnyDataSetBeginCreate().
Call OCIAnyDataSetAddInstance() to add a new instance; this call returns the OCIAnyData
corresponding to that instance.

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About Binding Named Data Types

Then, you can invoke the OCIAnyData functions to construct this instance. Call
OCIAnyDataSetEndCreate() when all instances have been added.
For access, call OCIAnyDataSetGetInstance() to get the OCIAnyData corresponding to the
instance. Only sequential access is supported. Subsequently, you can invoke the
OCIAnyData access functions, as in the following example:
OCIAnyDataSetBeginCreate(...)
OCIAnyDataSetAddInstance(...)

OCIAnyDataSetEndCreate(...)

/* Begin AnyDataSet Creation */
/* Add a new instance to the AnyDataSet */
/* Use the OCIAnyData*() functions to create
the instance */
/* End OCIAnyDataSet Creation */

See Also:
•

OCIAnyDataSetBeginCreate()

•

OCIAnyDataSetAddInstance()

•

OCIAnyDataSetEndCreate()

•

OCIAnyDataSetGetInstance()

•

OCI Any Type and Data Functions for complete descriptions of all the
calls in these interfaces

20.14 About Binding Named Data Types
This section provides information about binding named data types (such as objects
and collections) and REFs.
This section includes the following topics:
•

Named Data Type Binds

•

About Binding REFs

•

Information for Named Data Type and REF Binds

•

Information Regarding Array Binds

20.14.1 Named Data Type Binds
For a named data type (object type or collection) bind, a second bind call is necessary
following OCIBindByName() or OCIBindByName2() or OCIBindByPos() or OCIBindByPos2().
The OCIBindObject() call sets up additional attributes specific to the object type bind.
An OCI application uses this call when fetching data from a table that has a column
with an object data type.
The OCIBindObject() call takes, among other parameters, a type descriptor object
(TDO) for the named data type. The TDO of data type OCIType is created and stored in
the database when a named data type is created. It contains information about the
type and its attributes. An application can obtain a TDO by calling OCITypeByName().
The OCIBindObject() call also sets up the indicator variable or structure for the named
data type bind.

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About Binding Named Data Types

When binding a named data type, use the SQLT_NTY data type constant to indicate the
data type of the program variable being bound. SQLT_NTY indicates that a C struct
representing the named data type is being bound. A pointer to this structure is passed
to the bind call.
With inheritance and instance substitutability, you can bind a subtype instance where
the supertype is expected.
Working with named data types may require the use of three bind calls in some
circumstances. For example, to bind a static array of named data types to a PL/SQL
table, three calls must be invoked: OCIBindByName() or OCIBindByName2(),
OCIBindArrayOfStruct(), and OCIBindObject().

See Also:
•

Fetching Embedded Objects for information about using these data
types to fetch an embedded object from the database

•

Information for Named Data Type and REF Binds

•

Descriptor Objects

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindObject()

•

OCITypeByName()

•

OCIBindArrayOfStruct()

20.14.2 About Binding REFs
As with named data types, binding REFs is a two-step process.
First, call OCIBindByName() or OCIBindByName2() or OCIBindByPos() or OCIBindByPos2(),
and then call OCIBindObject().
REFs are bound using the SQLT_REF data type. When SQLT_REF is used, then the program
variable being bound must be of type OCIRef *.

With inheritance and REF substitutability, you can bind a REF value to a subtype
instance where a REF to the supertype is expected.

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About Binding Named Data Types

See Also:
•

Retrieving an Object Reference from the Server for information about
binding and pinning REFs to objects

•

Information for Named Data Type and REF Binds for additional important
information

•

OCIBindByName() or OCIBindByName2()

•

OCIBindByPos() or OCIBindByPos2()

•

OCIBindObject()

20.14.3 Information for Named Data Type and REF Binds
Remember the following important information when you work with named data type
and REF binds.
It includes pointers about memory allocation and indicator variable usage.
•

If the data type being bound is SQLT_NTY, the indicator struct parameter of the
OCIBindObject() call (void ** indpp) is used, and the scalar indicator is completely
ignored.

•

If the data type is SQLT_REF, the scalar indicator is used, and the indicator struct
parameter of OCIBindObject() is completely ignored.

•

The use of indicator structures is optional. The user can pass a NULL pointer in the
indpp parameter for the OCIBindObject() call. During the bind, therefore, the object
is not atomically NULL and none of its attributes are NULL.

•

The indicator struct size pointer, indsp, and program variable size pointer, pgvsp, in
the OCIBindObject() call are optional. Users can pass NULL if these parameters are
not needed.

See Also:
OCIBindObject()

20.14.4 Information Regarding Array Binds
For doing array binds of named data types or REFs, for array inserts or fetches, the
user must pass in an array of pointers to buffers (preallocated or otherwise) of the
appropriate type.
Similarly, an array of scalar indicators for SQLT_REF types or an array of pointers to
indicator structs for SQLT_NTY types must be passed.

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About Defining Named Data Types

See Also:
Named Data Types: Object, VARRAY, Nested Table for more information
about SQLT_NTY

20.15 About Defining Named Data Types
This section provides information about defining named data types (for example,
objects, collections) and REFs.
This section includes the following topics:
•

About Defining Named Data Type Output Variables

•

About Defining REF Output Variables

•

Information for Named Data Type and REF Defines, and PL/SQL OUT Binds

20.15.1 About Defining Named Data Type Output Variables
For a named data type (object type, nested table, varray) define, two define calls are
necessary.
The application should first call OCIDefineByPos() or OCIDefineByPos2(), specifying
SQLT_NTY in the dty parameter. Following OCIDefineByPos() or OCIDefineByPos2(), the
application must call OCIDefineObject() to set up additional attributes pertaining to a
named data type define. In this case, the data buffer pointer in OCIDefineByPos() or
OCIDefineByPos2() is ignored.
Specify the SQLT_NTY data type constant for a named data type define. In this case, the
application fetches the result data into a host-language representation of the named
data type. In most cases, this is a C struct generated by the Object Type Translator.
To make an OCIDefineObject() call, a pointer to the address of the C struct
(preallocated or otherwise) must be provided. The object may have been created with
OCIObjectNew(), allocated in the cache, or with user-allocated memory.
However, in the presence of inheritance, Oracle strongly recommends using objects in
the object cache and not passing objects allocated out of user memory from the stack.
Otherwise, due to instance substitutability, the server may send back a subtype
instance when the client is expecting a supertype instance. This requires the server to
dynamically resize the object, which is possible only for objects in the cache.

See Also:
•

Information for Named Data Type and REF Defines, and PL/SQL OUT
Binds for more important information about defining named data types

•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIDefineObject()

•

OCIObjectNew()

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About Defining Named Data Types

20.15.2 About Defining REF Output Variables
As with named data types, defining for a REF output variable is a two-step process.
The first step is a call to OCIDefineByPos() or OCIDefineByPos2(), and the second is a
call to OCIDefineObject(). Also as with named data types, the SQLT_REF data type
constant is passed to the dty parameter of OCIDefineByPos().
SQLT_REF indicates that the application is fetching the result data into a variable of type
OCIRef *. This REF can then be used as part of object pinning and navigation.

See Also:
•

OCIDefineByPos() or OCIDefineByPos2()

•

OCIDefineObject()

•

Information for Named Data Type and REF Defines, and PL/SQL OUT
Binds for more important information about defining REFs

•

About Working with Objects in OCI for more information about object
pinning and navigation

20.15.3 Information for Named Data Type and REF Defines, and
PL/SQL OUT Binds
Consider the following important information as you work with named data type and
REF defines. It includes pointers about memory allocation and indicator variable usage.
A PL/SQL OUT bind refers to binding a placeholder to an output variable in a PL/SQL
block. Unlike a SQL statement, where output buffers are set up with define calls, in a
PL/SQL block, output buffers are set up with bind calls.
•

If the data type being defined is SQLT_NTY, then the indicator struct parameter of the
OCIDefineObject() call (void ** indpp) is used, and the scalar indicator is
completely ignored.

•

If the data type is SQLT_REF, then the scalar indicator is used, and the indicator
struct parameter of OCIDefineObject() is completely ignored.

•

The use of indicator structures is optional. The user can pass a NULL pointer in the
indpp parameter for the OCIDefineObject() call. During a fetch or PL/SQL OUT
bind, therefore, the user is not interested in any information about being null.

•

In a SQL define or PL/SQL OUT bind, you can pass in preallocated memory for
either the output variable or the indicator. Then that preallocated memory is used
to store result data, and any secondary memory (out-of-line memory), is
deallocated. The preallocated memory must come from the cache (the result of an
OCIObjectNew() call).

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About Defining Named Data Types

Note:
If you want your client application to allocate memory from its own
private memory space, instead of the cache, your application must
ensure that there is no secondary out-of-line memory in the object.
To preallocate object memory for an object define with type SQLT_NTY, client
applications must use the OCIObjectNew() function. A client application should not
allocate the object in its own private memory space, such as with malloc() or on the
stack. The OCIObjectNew() function allocates the object in the object cache. The
allocated object can be freed using OCIObjectFree().

Note:
There is no change to the behavior of OCIDefineObject() when the user does
not preallocate the object memory and instead initializes the output variable
to null pointer value. In this case, the object is implicitly allocated in the
object cache by the OCI library.

•

In a SQL define or PL/SQL OUT bind, if the user passes in a NULL address for the
output variable or the indicator, memory for the variable or the indicator is implicitly
allocated by OCI.

•

If an output object of type SQLT_NTY is atomically NULL (in a SQL define or PL/SQL
OUT bind), only the NULL indicator struct gets allocated (implicitly if necessary) and
populated accordingly to indicate the atomic nullity of the object. The top-level
object does not get implicitly allocated.

•

An application can free indicators by calling OCIObjectFree(). If there is a top-level
object (as with a non-atomically NULL object), then the indicator is freed when the
top-level object is freed with OCIObjectFree(). If the object is atomically null, then
there is no top-level object, so the indicator must be freed separately.

•

The indicator struct size pointer, indszp, and program variable size pointer, pvszsp,
in the OCIDefineObject() call are optional. Users can pass NULL if these parameters
are not needed.

This section includes the following topic: Information About Array Defines.

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About Binding and Defining Oracle C Data Types

See Also:
•

About Binding Placeholders in PL/SQL for more information

•

OCIDefineObject()

•

OCIObjectNew()

•

OCIObjectFree()

•

OCI Navigational and Type Functions for details about OCIObjectNew()
and OCIObjectFree()

•

OCIDefineObject()

20.15.3.1 Information About Array Defines
To perform array defines of named data types or REFs, the user must pass in an array
of pointers to buffers (preallocated or otherwise) of the appropriate type.
Similarly, an array of scalar indicators (for SQLT_REF types) or an array of pointers to
indicator structs (for SQLT_NTY types) must be passed.

20.16 About Binding and Defining Oracle C Data Types
This section summarizes information about binding and defining Oracle C named data
types
Previous chapters of this book have discussed OCI bind and define operations. About
Binding Placeholders in OCI discussed the basics of OCI bind operations, whereas
About Defining Output Variables in OCI discussed the basics of OCI define operations.
Information specific to binding and defining named data types and REFs was described
in Binding and Defining in OCI.
The sections covering basic bind and define functionality showed how an application
could use a scalar variable or array of scalars as an input (bind) value in a SQL
statement, or as an output (define) buffer for a query.
The sections covering named data types and REFs showed how to bind or define an
object or reference. Pinning an Object expanded on this to talk about pinning object
references, Fetching Embedded Objects discussed fetching embedded instances, and
Object Navigation discussed object navigation.
The purpose of this section is to cover binding and defining of individual attribute
values, using the data type mappings explained in this chapter.
Variables of one of the types defined in this chapter, such as OCINumber or OCIString,
can typically be declared in an application and used directly in an OCI bind or define
operation because the appropriate data type code is specified. Table 20-12 lists the
data types that you can use for binds and defines, along with their C mapping, and the
OCI external data type that must be specified in the dty (data type code) parameter of
the bind or define call.

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Chapter 20

About Binding and Defining Oracle C Data Types

Table 20-12

Data Type Mappings for Binds and Defines

Data Type

C Mapping

OCI External Data Type and Code

Oracle NUMBER

OCINumber

VARNUM (SQLT_VNU)

Oracle DATE

OCIDate

SQLT_ODT

OCILobLocator *

SQLT_BLOB

CILobLocator *

SQLTY_LOB

OCIString *

SQLT_VST 1

OCIRaw *

SQLT_LVB 1

OCIString *

SQLT_VST

struct *

Named Data Type (SQLT_NTY)

OCIRef *

REF (SQLT_REF)

OCIArray *

Named Data Type (SQLT_NTY)

OCITable *

Named Data Type (SQLT_NTY)

BLOB
CLOB, NCLOB
VARCHAR2, NVARCHAR2
RAW
CHAR, NCHAR
Object
REF
VARRAY
Nested Table
DATETIME
INTERVAL

1

OCIDateTime *

See Datetime and Interval (OCIDateTime,
OCIInterval).

OCIInterval *

See Datetime and Interval (OCIDateTime,
OCIInterval).

Before fetching data into a define variable of type OCIString *, the size of the string must first be set
using the OCIStringResize() routine. This may require a describe operation to obtain the length of the
select-list data. Similarly, an OCIRaw * must be first sized with OCIStringResize().

The following sections presents examples of how to use C-mapped data types in an
OCI application:
•

Bind and Define Examples

•

Salary Update Examples

20-40

Chapter 20

About Binding and Defining Oracle C Data Types

See Also:
•

Data Types for a discussion of OCI external data types, and a list of data
typecodes

•

OCIStringResize()

20.16.1 Bind and Define Examples
Shows how you can use variables of type OCINumber in OCI bind and define operations
The examples in this section demonstrate how you can use variables of type OCINumber
in OCI bind and define operations.
Assume, for this example, that the following person object type was created:
CREATE TYPE person AS OBJECT
(name
varchar2(30),
salary
number);

This type is then used to create an employees table that has a column of type person.
CREATE TABLE employees
(emp_id
number,
job_title varchar2(30),
emp
person);

The Object Type Translator (OTT) generates the following C struct and null indicator
struct for person:
struct person
{ OCIString * name;
OCINumber salary;};
typedef struct person person;
struct person_ind
{ OCIInd _atomic;
OCIInd name;
OCIInd salary;}
typedef struct person_ind person_ind;

Assume that the employees table has been populated with values, and an OCI
application has declared a person variable:
person *my_person;

The application then fetches an object into that variable through a SELECT statement,
such as:
text *mystmt = (text *) "SELECT person FROM employees
WHERE emp.name='Andrea'";

This requires defining my_person to be the output variable for this statement, using
appropriate OCI define calls for named data types, as described in Advanced Define
Operations in OCI. Executing the statement retrieves the person object named Andrea
into the my_person variable.

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Once the object is retrieved into my_person, the OCI application has access to the
attributes of my_person, including the name and the salary.
The application could go on to update another employee's salary to be the same as
Andrea's, as in the following example:
text *updstmt = (text *) "UPDATE employees SET emp.salary = :newsal
WHERE emp.name = 'MONGO'";

Andrea's salary (stored in my_person->salary) would be bound to the
placeholder :newsal, specifying an external data type of VARNUM (data type code=6) in
the bind operation:
OCIBindByName(...,":newsal",...,&my_person->salary,...,6,...);
OCIStmtExecute(...,updstmt,...);

Executing the statement updates Mongo's salary in the database to be equal to
Andrea's, as stored in my_person.
Conversely, the application could update Andrea's salary to be the same as Mongo's,
by querying the database for Mongo's salary, and then making the necessary salary
assignment:
text *selstmt = (text *) "SELECT emp.salary FROM employees
WHERE emp.name = 'MONGO'";
OCINumber mongo_sal;
...
OCIDefineByPos(...,1,...,&mongo_sal,...,6,...);
OCIStmtExecute(...,selstmt,...);
OCINumberAssign(...,&mongo_sal, &my_person->salary);

In this case, the application declares an output variable of type OCINumber and uses it in
the define step. The application also defines an output variable for position 1, and uses
the appropriate data type code (6 for VARNUM).
The salary value is fetched into the mongo_sal OCINumber, and the appropriate OCI
function, OCINumberAssign(), is used to assign the new salary to the copy of the Andrea
object currently in the cache. To modify the data in the database, the change must be
flushed to the server.

See Also:
•

Using the Object Type Translator with OCI for a complete discussion of
OTT

•

OCINumberAssign()

20.16.2 Salary Update Examples
Shows how the flow of calls is used to perform certain OCI tasks.
The examples in the previous section demonstrate the flexibility that the Oracle data
types provide for bind and define operations. This section shows how you can perform
the same operation in several different ways. You can use these data types in variety
of ways in OCI applications.

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The examples in this section demonstrate the flow of calls used to perform certain OCI
tasks. An expanded pseudocode is used for these examples. Actual function names
are used, but for simplicity not all parameters and typecasts are filled in. Other
necessary OCI calls, such as handle allocations, have been omitted.
The Scenario
The scenario for these examples is as follows:
•

An employee named BRUCE exists in the employees table for a hospital. See person
type and employees table creation statements in the previous section.

•

Bruce's current job title is RADIOLOGIST.

•

Bruce is being promoted to RADIOLOGY_CHIEF, and along with the promotion comes
a salary increase.

•

Hospital salaries are in whole dollar values, are set according to job title, and are
stored in a table called salaries, defined as follows:
CREATE TABLE salaries
(job_title varchar2(20),
salary
integer));

•

Bruce's salary must be updated to reflect his promotion.

To update Bruce's salary to reflect the promotion, the application must retrieve the
salary corresponding to RADIOLOGY_CHIEF from the salaries table, and update Bruce's
salary. A separate step would write his new title and the modified object back to the
database.
Assume that a variable of type person has been declared as follows:
person * my_person;

The object corresponding to Bruce has been fetched into person. The following
sections present three different ways in which the salary update could be performed.
This section includes the following topics:
•

Method 1 - Fetch, Convert, Assign

•

Method 2 - Fetch and Assign

•

Method 3 - Direct Fetch

•

Summary and Notes

20.16.2.1 Method 1 - Fetch, Convert, Assign
Shows how to fetch the new salary, convert the integer data type to OCINumber, then
assign the new salary to an employee.
Example 20-13 uses the following method:
1.

Do a traditional OCI define using an integer variable to retrieve the new salary
from the database.

2.

Convert the integer to an OCINumber.

3.

Assign the new salary to Bruce.

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Example 20-13

Method 1 for a Salary Update: Fetch, Convert, and Assign

#define INT_TYPE 3

/* data type code for sword integer define */

text *getsal = (text *) "SELECT salary FROM salaries
WHERE job_title='RADIOLOGY_CHIEF'";
sword
new_sal;
OCINumber orl_new_sal;
...
OCIDefineByPos(...,1,...,new_sal,...,INT_TYPE,...);
/* define int output */
OCIStmtExecute(...,getsal,...);
/* get new salary as int */
OCINumberFromInt(...,new_sal,...,&orl_new_sal);
/* convert salary to OCINumber */
OCINumberAssign(...,&orl_new_sal, &my_person->salary);
/* assign new salary */

20.16.2.2 Method 2 - Fetch and Assign
Shows how to fetch the salary and get it as an OCINumber and then assign the new
salary to an employee.
This method (Example 20-14) eliminates one of the steps described in Method 1.
1.

Define an output variable of type OCINumber, so that no conversion is necessary
after the value is retrieved.

2.

Assign the new salary to Bruce.

Example 20-14

Method 2 for a Salary Update: Fetch and Assign, No Convert

#define VARNUM_TYPE 6

/* data type code for defining VARNUM */

text *getsal = (text *) "SELECT salary FROM salaries
WHERE job_title='RADIOLOGY_CHIEF'";
OCINumber orl_new_sal;
...
OCIDefineByPos(...,1,...,orl_new_sal,...,VARNUM_TYPE,...);
/* define OCINumber output */
OCIStmtExecute(...,getsal,...);
/* get new salary as OCINumber */
OCINumberAssign(...,&orl_new_sal, &my_person->salary);
/* assign new salary */

20.16.2.3 Method 3 - Direct Fetch
Shows how to do the entire operation with a single define and fetch.
This method (Example 20-15) accomplishes the entire operation with a single define
and fetch. No intervening output variable is used, and the value retrieved from the
database is fetched directly into the salary attribute of the object stored in the cache.
Because the object corresponding to Bruce is pinned in the object cache, use the
location of his salary attribute as the define variable, and execute or fetch directly into
it.
Example 20-15

Method 3 for a Salary Update: Direct Fetch

#define VARNUM_TYPE 6

/* data type code for defining VARNUM */

text *getsal = (text *) "SELECT salary FROM salaries

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SQLT_NTY Bind and Define Examples

WHERE job_title='RADIOLOGY_CHIEF'";
...
OCIDefineByPos(...,1,...,&my_person->salary,...,VARNUM_TYPE,...);
/* define bruce's salary in cache as output variable */
OCIStmtExecute(...,getsal,...);
/* execute and fetch directly */

20.16.2.4 Summary and Notes
Summarizes what the previous examples demonstrated and highlights additional
information.
As the previous three examples show, the C data types provide flexibility for binding
and defining. In these examples an integer can be fetched, and then converted to an
OCINumber for manipulation. You can use an OCINumber as an intermediate variable to
store the results of a query. Or, data can be fetched directly into a desired OCINumber
attribute of an object.

Note:
In these examples it is important to remember that in OCI, if an output
variable is defined before the execution of a query, the resulting data is
prefetched directly into the output buffer.

In the preceding examples, extra steps would be necessary to ensure that the
application writes changes to the database permanently. These might involve SQL
UPDATE calls and OCI transaction commit calls.
These examples all dealt with define operations, but a similar situation applies for
binding.
Similarly, although these examples dealt exclusively with the OCINumber type, a similar
variety of operations are possible for the other Oracle C types described in the
remainder of this chapter.

20.17 SQLT_NTY Bind and Define Examples
The following code fragments demonstrate the use of the SQLT_NTY named data type in
the bind call including OCIBindObject() and the SQLT_NTY named data type in the define
call including OCIDefineObject().
In each example, a previously defined SQL statement is being processed.
This section includes the following topics:
•

SQLT_NTY Bind Example

•

SQLT_NTY Define Example

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Chapter 20

SQLT_NTY Bind and Define Examples

See Also:
•

OCIBindObject()

•

OCIDefineObject()

20.17.1 SQLT_NTY Bind Example
Shows how to use the SQLT_NTY named data type in the bind call including
OCIBindObject().
Example 20-16 shows how to use the SQLT_NTY named data type in the bind call
including OCIBindObject().
Example 20-16

Using the SQLT_NTY Bind Call Including OCIBindObject()

/*
** This example performs a SQL insert statement
*/
void insert(envhp, svchp, stmthp, errhp, insstmt, nrows)
OCIEnv *envhp;
OCISvcCtx *svchp;
OCIStmt *stmthp;
OCIError *errhp;
text *insstmt;
ub2 nrows;
{
OCIType *addr_tdo = (OCIType *)0 ;
address addrs;
null_address naddrs;
address *addr = &addrs;
null_address *naddr = &naddrs;
sword custno =300;
OCIBind *bnd1p, *bnd2p;
ub2 i;
/* define the application request */
checkerr(errhp, OCIStmtPrepare(stmthp, errhp, (text *) insstmt,
(ub4) strlen((char *)insstmt),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT));
/* bind the input variable */
checkerr(errhp, OCIBindByName(stmthp, &bnd1p, errhp, (text *) ":custno",
(sb4) -1, (void *) &custno,
(sb4) sizeof(sword), SQLT_INT,
(void *) 0, (ub2 *)0, (ub2 *)0, (ub4) 0, (ub4 *) 0,
(ub4) OCI_DEFAULT));
checkerr(errhp, OCIBindByName(stmthp, &bnd2p, errhp, (text *) ":addr",
(sb4) -1, (void *) 0,
(sb4) 0, SQLT_NTY, (void *) 0, (ub2 *)0, (ub2 *)0,
(ub4) 0, (ub4 *) 0, (ub4) OCI_DEFAULT));
checkerr(errhp,
OCITypeByName(envhp, errhp, svchp, (const text *)
SCHEMA, (ub4) strlen((char *)SCHEMA),
(const text *)"ADDRESS_VALUE",

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(ub4) strlen((char *)"ADDRESS_VALUE"),
(text *)0, 0, OCI_DURATION_SESSION,
OCI_TYPEGET_HEADER, &addr_tdo));
if(!addr_tdo)
{
printf("Null tdo returned\n");
return;
}
checkerr(errhp, OCIBindObject(bnd2p, errhp, addr_tdo, (void **) &addr,
(ub4 *) 0, (void **) &naddr, (ub4 *) 0));

See Also:
OCIBindObject()

20.17.2 SQLT_NTY Define Example
Shows how to use the SQLT_NTY named data type in the define call including
OCIDefineObject().

Example 20-17 shows how to use the SQLT_NTY named data type in the define call
including OCIDefineObject().
Example 20-17

Using the SQLT_NTY Define Call Including OCIDefineObject()

/*
** This example executes a SELECT statement from a table that includes
** an object.
*/
void selectval(envhp, svchp, stmthp, errhp)
OCIEnv *envhp;
OCISvcCtx *svchp;
OCIStmt *stmthp;
OCIError *errhp;
{
OCIType *addr_tdo = (OCIType *)0;
OCIDefine *defn1p, *defn2p;
address *addr = (address *)NULL;
sword custno =0;
sb4 status;
/* define the application request */
checkerr(errhp, OCIStmtPrepare(stmthp, errhp, (text *) selvalstmt,
(ub4) strlen((char *)selvalstmt),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT));
/* define the output variable */
checkerr(errhp, OCIDefineByPos(stmthp, &defn1p, errhp, (ub4) 1, (void *)
&custno, (sb4) sizeof(sword), SQLT_INT, (void *) 0, (ub2 *)0,
(ub2 *)0, (ub4) OCI_DEFAULT));
checkerr(errhp, OCIDefineByPos(stmthp, &defn2p, errhp, (ub4) 2, (void *)
0, (sb4) 0, SQLT_NTY, (void *) 0, (ub2 *)0,
(ub2 *)0, (ub4) OCI_DEFAULT));

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checkerr(errhp,
OCITypeByName(envhp, errhp, svchp, (const text *)
SCHEMA, (ub4) strlen((char *)SCHEMA),
(const text *) "ADDRESS_VALUE",
(ub4) strlen((char *)"ADDRESS_VALUE"),
(text *)0, 0, OCI_DURATION_SESSION,
OCI_TYPEGET_HEADER, &addr_tdo));
if(!addr_tdo)
{
printf("NULL tdo returned\n");
return;
}

checkerr(errhp, OCIDefineObject(defn2p, errhp, addr_tdo, (void **)
&addr, (ub4 *) 0, (void **) 0, (ub4 *) 0));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4) 0,
(OCISnapshot *) NULL, (OCISnapshot *) NULL, (ub4) OCI_DEFAULT));

See Also:
OCIDefineObject()

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21
Direct Path Load Interface
The direct path loading functions are used to load data from external files into tables
and partitions.
This chapter contains these topics:
•

Direct Path Loading Overview

•

Direct Path Loading of Object Types

•

Direct Path Loading in Pieces

•

Direct Path Context Handles and Attributes for Object Types

21.1 Direct Path Loading Overview
The direct path load interface enables an OCI application to access the direct path
load engine of Oracle Database to perform the functions of the SQL*Loader utility.
This functionality provides the ability to load data from external files into either a table
or a partition of a partitioned table.
Figure 21-1 introduces the subject of this chapter. On the client side of the illustration,
data enters a column array through an input buffer. The OCIDirPathColArrayToStream()
call moves the data to the server side through stream formats. These pass data to a
column array that uses a block formatter to send the data to the database table.

Figure 21-1

Direct Path Loading
Client

Server

Data

Input
Buffer

Two-Task
Stream
Format

Column
Array

Stream
Format

ColumnArrayToStream
Column
Array
Block
Formatter

OracleTable

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Chapter 21

Direct Path Loading Overview

The OCI direct path load interface can load multiple rows by loading a direct path
stream that contains data for multiple rows.
To use the direct path API, the client application performs the following steps:
1.

Initialize OCI.

2.

Allocate a direct path context handle and set the attributes.

3.

Supply the name of the object (table, partition, or subpartition) to be loaded.

4.

Describe the external data types of the columns of the object.

5.

Prepare the direct path interface.

6.

Allocate one or more column arrays.

7.

Allocate one or more direct path streams.

8.

Set entries in the column array to point to the input data value for each column.

9.

Convert a column array to a direct path stream format.

10. Load the direct path stream.
11. Retrieve any errors that may have occurred.
12. Invoke the direct path finishing function.
13. Free handles and data structures.
14. Disconnect from the server.

Steps 8 through 11 can be repeated many times, depending on the data to be loaded.
A direct load operation requires that the object being loaded is locked to prevent DML
operations on the object. Note that queries are lock-free and are allowed while the
object is being loaded. The mode of the DML lock, and which DML locks are obtained,
depend upon the specification of the OCI_ATTR_DIRPATH_PARALLEL option, and if a
partition or subpartition load is being done as opposed to an entire table load.
•

•

For a table load, if the OCI_ATTR_DIRPATH_PARALLEL option is set to:
–

FALSE, then the table DML X-Lock is acquired

–

TRUE, then the table DML S-Lock is acquired

For a partition load, if the OCI_ATTR_DIRPATH_PARALLEL option is set to:
–

FALSE, then the table DML SX-Lock and partition DML X-Lock are acquired

–

TRUE, then the table DML SS-Lock and partition DML S-Lock are acquired

This section includes the following topics:
•

Data Types Supported for Direct Path Loading

•

Direct Path Handles

•

About Direct Path Interface Functions

•

Limitations and Restrictions of the Direct Path Load Interface

•

Direct Path Load Examples for Scalar Columns

•

About Using a Date Cache in Direct Path Loading of Dates in OCI

•

About Validating Format for Oracle NUMBER and DATE Data

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Direct Path Loading Overview

See Also:
•

Direct Path Context Handle (OCIDirPathCtx) Attributes

•

OCIDirPathColArrayToStream()

21.1.1 Data Types Supported for Direct Path Loading
Lists the external data types that are valid for scalar columns in a direct path load
operation.
The following external data types are valid for scalar columns in a direct path load
operation:
•

SQLT_CHR

•

SQLT_DAT

•

SQLT_INT

•

SQLT_UIN

•

SQLT_FLT

•

SQLT_BIN

•

SQLT_NUM

•

SQLT_PDN

•

SQLT_CLOB

•

SQLT_BLOB

•

SQLT_DATE

•

SQLT_TIMESTAMP

•

SQLT_TIMESTAMP_TZ

•

SQLT_TIMESTAMP_LTZ

•

SQLT_INTERVAL_YM

•

SQLT_INTERVAL_DS

The following external object data types are supported:
•

SQLT_NTY - column objects (FINAL and NOT FINAL) and SQL string columns

•

SQLT_REF - REF columns (FINAL and NOT FINAL)

The following table types are supported:
•

Nested tables

•

Object tables (FINAL and NOT FINAL)

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Direct Path Loading Overview

See Also:
•

About Accessing Column Parameter Attributes for information on setting
or retrieving the data type of a column

•

Table 5-2 for information about data types

21.1.2 Direct Path Handles
A direct path load corresponds to a direct path array insert operation.
The direct path load interface uses the following handles to keep track of the objects
loaded and the specification of the data operated on:
•

Direct Path Context

•

OCI Direct Path Function Context

•

Direct Path Column Array and Direct Path Function Column Array

•

Direct Path Stream

See Also:
Direct Path Loading Handle Attributes and all the descriptions of direct
path attributes that follow

21.1.2.1 Direct Path Context
The direct path context handle must be allocated for each object, either a table or a
partition of a partitioned table, being loaded.
Because an OCIDirPathCtx handle is the parent handle of the OCIDirPathFuncCtx,
OCIDirPathColArray, and OCIDirPathStream handles, freeing an OCIDirPathCtx handle
frees its child handles also (although for good coding practices, free child handles
individually before you free the parent handle).
A direct path context is allocated with OCIHandleAlloc(). Note that the parent handle of
a direct path context is always the environment handle. A direct path context is freed
with OCIHandleFree(). Include the header files in the first two lines in all direct path
programs, as shown in Example 21-1.
Example 21-1

Direct Path Programs Must Include the Header Files

...
#include 
#include 
OCIEnv *envp;
OCIDirPathCtx *dpctx;
sword error;
error = OCIHandleAlloc((void *)envp, (void **)&dpctx,
OCI_HTYPE_DIRPATH_CTX, (size_t)0,(void **)0);

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...
error = OCIHandleFree(dpctx, OCI_HTYPE_DIRPATH_CTX);

See Also:
•

OCIHandleAlloc()

•

OCIHandleFree()

21.1.2.2 OCI Direct Path Function Context
Use the direct path function context handle to describe named type and REF columns:
column objects, REF columns, and SQL string columns.
The direct path function context handle, of type OCIDirPathFuncCtx, is used to describe
the following named type and REF columns:
•

Column objects. The function context here describes the object type, which is to
be used as the default constructor to construct the object, and the object attributes
of the constructor.

•

REF columns. The function context here describes a single object table (optional) to
reference row objects from, and the REF arguments that identify each row object.

•

SQL string columns. The function context here describes a SQL string and its
arguments to compute the value to be loaded into the column.

The handle type OCI_HTYPE_DIRPATH_FN_CTX is passed to OCIHandleAlloc() to indicate
that a function context is to be allocated, as shown in Example 21-2.
Note that the parent handle of a direct path function context is always the direct path
context handle. A direct path function context handle is freed with OCIHandleFree():
error = OCIHandleFree(dpfnctx, OCI_HTYPE_DIRPATH_FN_CTX);

Example 21-2

Passing the Handle Type to Allocate the Function Context

OCIDirPathCtx *dpctx;
/* direct path context */
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(size_t)0, (void **)0);

See Also:
•

Oracle Database Object-Relational Developer's Guide for more
information about the data types supported

•

OCIHandleAlloc()

•

OCIHandleFree()

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Direct Path Loading Overview

21.1.2.3 Direct Path Column Array and Direct Path Function Column Array
The direct path column array handle and direct path function column handle are used
to present an array of rows to the direct path interface.
A row is represented by three arrays: column values, column lengths, and column
flags. Methods used on a column array include: allocate the array handle and set or
get values corresponding to an array entry.
Both handles share the same data structure, OCIDirPathColArray, but these column
array handles differ in parent handles and handle types.
A direct path column array handle is allocated with OCIHandleAlloc(). The code
fragment in Example 21-3 shows explicit allocation of the direct path column array
handle.
A direct path column array handle is freed with OCIHandleFree().
error = OCIHandleFree(dpca, OCI_HTYPE_DIRPATH_COLUMN_ARRAY);

Example 21-4 shows that a direct path function column array handle is allocated in
almost the same way.
A direct path function column array is freed with OCIHandleFree():
error = OCIHandleFree(dpfnca, OCI_HTYPE_DIRPATH_FN_COL_ARRAY);

Freeing an OCIDirPathColArray handle also frees the column array associated with the
handle.
Example 21-3

Explicit Allocation of Direct Path Column Array Handle

OCIDirPathCtx *dpctx;
/* direct path context */
OCIDirPathColArray *dpca; /* direct path column array */
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpca,
OCI_HTYPE_DIRPATH_COLUMN_ARRAY,
(size_t)0, (void **)0);

Example 21-4

Explicit Allocation of Direct Path Function Column Array Handle

OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
OCIDirPathColArray *dpfnca; /* direct path function column array */
sword error;
error = OCIHandleAlloc((void *)dpfnctx, (void **)&dpfnca,
(ub4)OCI_HTYPE_DIRPATH_FN_COL_ARRAY,
(size_t)0, (void **)0);

See Also:
OCIHandleAlloc()

21.1.2.4 Direct Path Stream
A direct path stream is a linear representation of Oracle table data.

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The direct path stream handle is used by the conversion operation,
OCIDirPathColArrayToStream(), and by the load operation, OCIDirPathLoadStream().
Direct path stream handles are allocated by the client with OCIHandleAlloc(). The
structure of an OCIDirPathStream handle can be thought of as a pair in the form (buffer,
buffer length).
The conversion operations always append to the end of the stream. Load operations
always start from the beginning of the stream. After a stream is completely loaded, the
stream must be reset by calling OCIDirPathStreamReset().
Example 21-5 shows a direct path stream handle allocated with OCIHandleAlloc(). The
parent handle is always an OCIDirPathCtx handle.
A direct path stream handle is freed using OCIHandleFree().
error = OCIHandleFree(dpstr, OCI_HTYPE_DIRPATH_STREAM);

Freeing an OCIDirPathStream handle also frees the stream buffer associated with the
handle.
Example 21-5

Allocating a Direct Path Stream Handle

OCIDirPathCtx *dpctx;
/* direct path context */
OCIDirPathStream *dpstr; /* direct path stream */
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpstr,
OCI_HTYPE_DIRPATH_STREAM, (size_t)0,(void **)0);

See Also:
•

OCIDirPathColArrayToStream()

•

OCIDirPathLoadStream()

•

OCIHandleAlloc()

•

OCIDirPathStreamReset()

21.1.3 About Direct Path Interface Functions
Lists and describes the functions used with the direct path load interface.
The functions listed in this section are used with the direct path load interface.
Operations on the direct path context are performed by the functions in Table 21-1.
Table 21-1

Direct Path Context Functions

Function

Purpose

OCIDirPathAbort()

Terminates a direct path operation

OCIDirPathDataSave()

Executes a data savepoint

OCIDirPathFinish()

Commits the loaded data

OCIDirPathFlushRow()

Flushes a partially loaded row from the server. This function
is deprecated.

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Chapter 21

Direct Path Loading Overview

Table 21-1

(Cont.) Direct Path Context Functions

Function

Purpose

OCIDirPathLoadStream()

Loads the data that has been converted to direct path stream
format

OCIDirPathPrepare()

Prepares the direct path interface to convert or load rows

Operations on the direct path column array are performed by the functions in
Table 21-2.
Table 21-2

Direct Path Column Array Functions

Function

Purpose

OCIDirPathColArrayEntryGet()

Gets a specified entry in a column array

OCIDirPathColArrayEntrySet()

Sets a specified entry in a column array to a specific
value

OCIDirPathColArrayRowGet()

Gets the base row pointers for a specified row
number

OCIDirPathColArrayReset()

Resets the row array state

OCIDirPathColArrayToStream()

Converts from a column array format to a direct path
stream format

Operations on the direct path stream are performed by the function
OCIDirPathStreamReset() that resets the direct stream state.

See Also:
Direct Path Loading Functions for detailed descriptions of each function

21.1.4 Limitations and Restrictions of the Direct Path Load Interface
Lists the limitations of the direct path load interface.
The direct path load interface has the following limitations that are the same as
SQL*Loader:
•

Triggers are not supported.

•

Referential integrity constraints are not supported.

•

Clustered tables are not supported.

•

Loading of remote objects is not supported.

•

LONGs must be specified last.

•

SQL strings that return LOBs, objects, or collections are not supported.

•

Loading of VARRAY columns is not supported.

•

All partitioning columns must come before any LOBs. This is because you must
determine what partition the LOB goes into before you start writing to it.

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21.1.5 Direct Path Load Examples for Scalar Columns
This section describes the direct path load examples for scalar columns.
This is described in the following topics:
•

Data Structures Used in Direct Path Loading Example

•

Outline of an Example of a Direct Path Load for Scalar Columns

21.1.5.1 Data Structures Used in Direct Path Loading Example
Shows examples that use the data structures in direct path loading.
Example 21-6 shows the data structure used in Example 21-7 through Example 21-17.
Example 21-7 shows the header file cdemodp.h from the demo directory, which defines
several structs.
Example 21-6

Data Structures Used in Direct Path Loading Examples

/* load control structure */
struct loadctl
{
ub4
nrow_ctl;
/* number of rows in column array */
ub2
ncol_ctl;
/* number of columns in column array */
OCIEnv
*envhp_ctl;
/* environment handle */
OCIServer
*srvhp_ctl;
/* server handle */
OCIError
*errhp_ctl;
/* error handle */
OCIError
*errhp2_ctl;
/* yet another error handle */
OCISvcCtx
*svchp_ctl;
/* service context */
OCISession
*authp_ctl;
/* authentication context */
OCIParam
*colLstDesc_ctl;
/* column list parameter handle */
OCIDirPathCtx
*dpctx_ctl;
/* direct path context */
OCIDirPathColArray *dpca_ctl;
/* direct path column array handle */
OCIDirPathColArray *dpobjca_ctl;
/* dp column array handle for obj*/
OCIDirPathColArray *dpnestedobjca_ctl; /* dp col array hndl for nested obj*/
OCIDirPathStream *dpstr_ctl;
/* direct path stream handle */
ub1
*buf_ctl;
/* pre-alloc'd buffer for out-of-line data */
ub4
bufsz_ctl;
/* size of buf_ctl in bytes */
ub4
bufoff_ctl;
/* offset into buf_ctl */
ub4
*otor_ctl;
/* Offset to Recnum mapping */
ub1
*inbuf_ctl;
/* buffer for input records */
struct pctx
pctx_ctl;
/* partial field context */
boolean
loadobjcol_ctl;
/* load to obj col(s)? T/F */
};

Example 21-7

Contents of the Header File cdemodp.h

#ifndef cdemodp_ORACLE
# define cdemodp_ORACLE
# include 
# ifndef externdef
# define externdef
# endif
/* External column attributes */
struct col

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{
text *name_col;
ub2 id_col;
ub2 exttyp_col;
text *datemask_col;
ub1 prec_col;
sb1 scale_col;
ub2 csid_col;
ub1 date_col;
struct obj * obj_col;
#define COL_OID 0x1
ub4 flag_col;
};

/* column name
/* column load ID
/* external type
/* datemask, if applicable
/* precision, if applicable
/* scale, if applicable
/* character set ID
/* is column a chrdate or date? 1=TRUE. 0=FALSE
/* description of object, if applicable */
/* col is an OID

/* Input field descriptor
* For this example (and simplicity),
* fields are strictly positional.
*/
struct fld
{
ub4 begpos_fld;
ub4 endpos_fld;
ub4 maxlen_fld;
ub4
flag_fld;
#define FLD_INLINE
0x1
#define FLD_OUTOFLINE
0x2
#define FLD_STRIP_LEAD_BLANK 0x4
#define FLD_STRIP_TRAIL_BLANK 0x8
};
struct obj
{
text
ub2
struct col
struct fld
ub4
ub4
OCIDirPathFuncCtx
OCIDirPathColArray
ub4
#define OBJ_OBJ 0x1
#define OBJ_OPQ 0x2
#define OBJ_REF 0x4
};
struct tbl
{
text
text
text
ub2
text
struct col
struct fld
ub1
ub1
ub4
text
};

*/
*/
*/
*/
*/
*/
*/
*/
*/

/* 1-based beginning position */
/* 1-based ending
position */
/* max length for out-of-line field */

*name_obj;
/* type name*/
ncol_obj;
/* number of columns in col_obj*/
*col_obj;
/* column attributes*/
*fld_obj;
/* field descriptor*/
rowoff_obj; /* current row offset in the column array*/
nrows_obj;
/* number of rows in col array*/
*ctx_obj;
/* Function context for this obj column*/
*ca_obj;
/* column array for this obj column*/
flag_obj;
/* type of obj */
/* obj col */
/* opaque/sql str col */
/* ref col */

*owner_tbl;
/* table owner
*name_tbl;
/* table name
*subname_tbl;
/* subname, if applicable
ncol_tbl;
/* number of columns in col_tbl
*dfltdatemask_tbl;
/* table level default date mask
*col_tbl;
/* column attributes
*fld_tbl;
/* field descriptor
parallel_tbl;
/* parallel: 1 for true
nolog_tbl;
/* no logging: 1 for true
xfrsz_tbl;
/* transfer buffer size in bytes
*objconstr_tbl; /* obj constr/type if loading a derived obj

*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/

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struct sess
{
text
text
text
text
ub4
};
#endif

/* options for a direct path load session */
*username_sess;
*password_sess;
*inst_sess;
*outfn_sess;
maxreclen_sess;

/* user
/* password
/* remote instance name
/* output filename
/* max size of input record in bytes

*/
*/
*/
*/
*/

/* cdemodp_ORACLE */

21.1.5.2 Outline of an Example of a Direct Path Load for Scalar Columns
Shows sample code that illustrates the use of several of the OCI direct path interfaces.
Example 21-8 shows sample code that illustrates the use of several of the OCI direct
path interfaces. It is not a complete code example.
The init_load function performs a direct path load using the direct path API on the table
described by tblp. The loadctl structure given by ctlp has an appropriately initialized
environment and service context. A connection has been made to the server.
Additional attributes, such as OCI_ATTR_SUB_NAME and OCI_ATTR_SCHEMA_NAME, are also set
here. After the attributes have been set, prepare the load.
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIDirPathPrepare(dpctx, ctlp->svchp_ctl, ctlp->errhp_ctl));

Allocate the Column Array and Stream Handles
Note that the direct path context handle is the parent handle for the column array and
stream handles, as shown in Example 21-9. Also note that errors are returned with the
environment handle associated with the direct path context.
Get the Number of Rows and Columns
Get the number of rows and columns in the column array just allocated, as shown in
Example 21-10.
Set the Input Data Fields
Set the input data fields to their corresponding data columns, as shown in
Example 21-11.
Reset the Column Array State
Reset the column array state in case a previous conversion must be continued or a
row is expecting more data, as shown in Example 21-12.
Reset the Stream State
Reset the stream state to start a new stream, as shown in Example 21-13. Otherwise,
data in the stream is appended to existing data.
Convert the Data in the Column Array to Stream Format
After inputting the data, convert the data in the column array to stream format and filter
out any bad records, as shown in Example 21-14.

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Load the Stream
Note that the position in the stream is maintained internally to the stream handle, along
with offset information for the column array that produced the stream. When the
conversion to stream format is done, the data is appended to the stream, as shown in
Example 21-15. It is the responsibility of the caller to reset the stream when
appropriate. On errors, the position is moved to the next row, or to the end of the
stream if the error occurs on the last row. The next OCIDirPathLoadStream() call starts
on the next row, if any. If an OCIDirPathLoadStream() call is made and the end of a
stream has been reached, OCI_NO_DATA is returned.
Finish the Direct Path Load
Finish the direct path load as shown in Example 21-16.
Free the Direct Path Handles
Free all the direct path handles allocated, as shown in Example 21-17. Note that the
direct path column array and stream handles are freed before the parent direct path
context handle is freed.
Example 21-8

Use of OCI Direct Path Interfaces

STATICF void
init_load(ctlp, tblp)
struct loadctl *ctlp;
struct tbl
*tblp;
{
struct col *colp;
struct fld *fldp;
sword
ociret;
OCIDirPathCtx *dpctx;
OCIParam
*colDesc;
ub1
parmtyp;
ub1
*timestamp = (ub1 *)0;
ub4
size;
ub4
i;
ub4
pos;

/* return code from OCI calls */
/* direct path context */
/* column parameter descriptor */

/* allocate and initialize a direct path context */
/* See cdemodp.c for the definition of OCI_CHECK */
OCI_CHECK(ctlp->envhp_ctl, OCI_HTYPE_ENV, ociret, ctlp,
OCIHandleAlloc((void *)ctlp->envhp_ctl,
(void **)&ctlp->dpctx_ctl,
(ub4)OCI_HTYPE_DIRPATH_CTX,
(size_t)0, (void **)0));
dpctx = ctlp->dpctx_ctl;

/* shorthand */

OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)dpctx, (ub4)OCI_HTYPE_DIRPATH_CTX,
(void *)tblp->name_tbl,
(ub4)strlen((const char *)tblp->name_tbl),
(ub4)OCI_ATTR_NAME, ctlp->errhp_ctl));

Example 21-9

Allocating the Column Array and Stream Handles

OCI_CHECK(ctlp->envhp_ctl, OCI_HTYPE_ENV, ociret, ctlp,
OCIHandleAlloc((void *)ctlp->dpctx_ctl, (void **)&ctlp->dpca_ctl,

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(ub4)OCI_HTYPE_DIRPATH_COLUMN_ARRAY,
(size_t)0, (void **)0));
OCI_CHECK(ctlp->envhp_ctl, OCI_HTYPE_ENV, ociret, ctlp,
OCIHandleAlloc((void *)ctlp->dpctx_ctl,(void **)&ctlp->dpstr_ctl,
(ub4)OCI_HTYPE_DIRPATH_STREAM,
(size_t)0, (void **)0));

Example 21-10

Getting the Number of Rows and Columns

OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrGet(ctlp->dpca_ctl, (ub4)OCI_HTYPE_DIRPATH_COLUMN_ARRAY,
&ctlp->nrow_ctl, 0, OCI_ATTR_NUM_ROWS,
ctlp->errhp_ctl));
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrGet(ctlp->dpca_ctl, (ub4)OCI_HTYPE_DIRPATH_COLUMN_ARRAY,
&ctlp->ncol_ctl, 0, OCI_ATTR_NUM_COLS,
ctlp->errhp_ctl));

Example 21-11
ub4
ub4
ub1
ub1

Setting Input Data Fields

rowoff;
clen;
cflg;
*cval;

/* column array row offset
/* column length
/* column state flag
/* column character value

*/
*/
*/
*/

OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIDirPathColArrayEntrySet(ctlp->dpca_ctl, ctlp->errhp_ctl,
rowoff, colp->id_col,
cval, clen, cflg));

Example 21-12

Resetting the Column Array State

(void) OCIDirPathColArrayReset(ctlp->dpca_ctl, ctlp->errhp_ctl);

Example 21-13

Resetting the Stream State

(void) OCIDirPathStreamReset(ctlp->dpstr_ctl, ctlp->errhp_ctl);

Example 21-14
ub4
ub4

Converting Data to Stream Format

rowcnt;
startoff;

/* number of rows in column array */
/* starting row offset into column array */

/* convert array to stream, filter out bad records */
ocierr = OCIDirPathColArrayToStream(ctlp->dpca_ctl, ctlp->dpctx_ctl,
ctlp->dpstr_ctl, ctlp->errhp_ctl,
rowcnt, startoff);

Example 21-15

Loading the Stream

/* load the stream */
ociret = OCIDirPathLoadStream(ctlp->dpctx_ctl, ctlp->dpstr_ctl,
ctlp->errhp_ctl);

Example 21-16

Finishing the Direct Path Load Operation

/* finish the direct path load operation */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIDirPathFinish(ctlp->dpctx_ctl, ctlp->errhp_ctl));

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Example 21-17

Freeing the Direct Path Handles

/* free up server data structures for the load */
ociret = OCIHandleFree((void *)ctlp->dpca_ctl,
OCI_HTYPE_DIRPATH_COLUMN_ARRAY);
ociret = OCIHandleFree((void *)ctlp->dpstr_ctl,
OCI_HTYPE_DIRPATH_STREAM);
ociret = OCIHandleFree((void *)ctlp->dpctx_ctl,
OCI_HTYPE_DIRPATH_CTX);

See Also:
OCIDirPathLoadStream()

21.1.6 About Using a Date Cache in Direct Path Loading of Dates in
OCI
The date cache feature provides improved performance when loading Oracle date and
time-stamp values that require data type conversions to be stored in the table.
For more information about using this feature in direct path loading, see Oracle
Database Utilities.
This feature is specifically targeted to direct path loads where the same input date or
timestamp values are being loaded over and over again. Date conversions are very
expensive and can account for a large percentage of the total load time, especially if
multiple date columns are being loaded. The date cache feature can significantly
improve performance by reducing the actual number of date conversions done when
many duplicate date values occur in the input data. However, date cache only
improves performance when many duplicate input date values are being loaded into
date columns (the word date in this chapter applies to all the date and time-stamp data
types).
The date cache is enabled by default. When you explicitly specify the date cache size,
the date cache feature is not disabled, by default. To override this behavior, set
OCI_ATTR_DIRPATH_DCACHE_DISABLE to 1. Otherwise, the cache continues to be searched
to avoid date conversions. However, any misses (entries for which there are no
duplicate values) are converted the usual way using expensive date conversion
functions without the benefit of using the date cache feature.
Query the attributes OCI_ATTR_DIRPATH_DCACHE_NUM, OCI_ATTR_DIRPATH_DCACHE_MISSES, and
OCI_ATTR_DIRPATH_DCACHE_HITS and then tune the cache size for future loads.
You can lower the cache size when there are no misses and the number of elements
in the cache is less than the cache size. The cache size can be increased if there are
many cache misses and relatively few hits (entries for which there are duplicate
values). Excessive date cache misses, however, can cause the application to run
slower than not using the date cache at all. Note that increasing the cache size too
much can cause other problems, like paging or exhausting memory. If increasing the
cache size does not improve performance, the feature should not be used.
The date cache feature can be explicitly and totally disabled by setting the date cache
size to 0.

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The following OCI direct path context attributes support this functionality:
•

OCI_ATTR_DIRPATH_DCACHE_SIZE

•

OCI_ATTR_DIRPATH_DCACHE_NUM

•

OCI_ATTR_DIRPATH_DCACHE_MISSES

•

OCI_ATTR_DIRPATH_DCACHE_HITS

•

OCI_ATTR_DIRPATH_DCACHE_DISABLE

21.1.6.1 OCI_ATTR_DIRPATH_DCACHE_SIZE
This attribute, when not equal to 0, sets the date cache size (in elements) for a table.
For example, if the date cache size is set to 200, then at most 200 unique date or timestamp values can be stored in the cache. The date cache size cannot be changed
once OCIDirPathPrepare() has been called. The default value is 0, meaning a date
cache is not created for a table. A date cache is created for a table only if one or more
date or time-stamp values are loaded that require data type conversions and the
attribute value is nonzero.

21.1.6.2 OCI_ATTR_DIRPATH_DCACHE_NUM
This attribute is used to query the current number of entries in a date cache.

21.1.6.3 OCI_ATTR_DIRPATH_DCACHE_MISSES
This attribute is used to query the current number of date cache misses. If the number
of misses is high, consider using a larger date cache size. If increasing the date cache
size does not cause this number to decrease significantly, the date cache should
probably not be used. Date cache misses are expensive, due to hashing and lookup
times.

21.1.6.4 OCI_ATTR_DIRPATH_DCACHE_HITS
This attribute is used to query the number of date cache hits. This number should be
relatively large to see any benefit of using the date cache support.

21.1.6.5 OCI_ATTR_DIRPATH_DCACHE_DISABLE
Used to disable the data cache if the size is exceeded.
Setting this attribute to 1 indicates that the date cache should be disabled if the size is
exceeded. Note that this attribute cannot be changed or set after OCIDirPathPrepare()
has been called.
The default (= 0) is to not disable a cache on overflow. When not disabled, the cache
is searched to avoid conversions, but overflow input date value entries are not added
to the date cache, and are converted using expensive date conversion functions.
Again, excessive date cache misses can cause the application to run slower than not
using the date cache at all.
This attribute can also be queried to see if a date cache has been disabled due to
overflow.

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See Also:
•

Direct Path Context Handle (OCIDirPathCtx) Attributes

•

OCIDirPathPrepare()

21.1.7 About Validating Format for Oracle NUMBER and DATE Data
Describes validating format for Oracle NUMBER and DATE data when loading stream
data.
Use the direct path context handle attribute OCI_ATTR_DIRPATH_FLAGS with the
OCI_DIRPATH_FLAGS_VLDT 0x01 flag set to validate format for Oracle NUMBER and DATE data
when the stream is parsed on the server. The default value is to not set this flag
because it is an expensive operation. It can be used when you suspect that there is a
problem with OCIDirPath generating invalid internal representation of dates and
numbers.
See Direct Path Context Handle (OCIDirPathCtx) Attributes for more information.

21.2 Direct Path Loading of Object Types
The use of the direct path function contexts to load various nonscalar types is
discussed in this section.
The nonscalar types are:
•

Nested tables

•

Object tables (FINAL and NOT FINAL)

•

Column objects (FINAL and NOT FINAL)

•

REF columns (FINAL and NOT FINAL)

•

SQL string columns

This section includes the following topics:
•

Direct Path Loading of Nested Tables

•

Direct Path Loading of Column Objects

•

Direct Path Loading of SQL String Columns

•

Direct Path Loading of REF Columns

•

Direct Path Loading of NOT FINAL Object and REF Columns

•

Direct Path Loading of Object Tables

•

Direct Path Loading a NOT FINAL Object Table

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See Also:
Table B-1 for a listing of the programs demonstrating direct path loading that
are available with your Oracle Database installation

21.2.1 Direct Path Loading of Nested Tables
Nested tables are stored in a separate table.
Using the direct path loading API, a nested table is loaded separately from its parent
table with a foreign key, called a SETID, to link the two tables together.

Note:
•

Currently, the SETIDs must be user-supplied and are not systemgenerated.

•

When loading the parent and child tables separately, it is possible for
orphaned children to be created when the rows are inserted in to the
child table, but the corresponding parent row is not inserted in to the
parent table. It is also possible to insert a parent row in to the parent
table without inserting child rows in to the child table, so that the parent
row has missing children.

21.2.1.1 Describing a Nested Table Column and Its Nested Table
Lists and describes loading the parent table with a nested table column, whichis a
separate action from loading the child nested table.

Note:
Steps that are different from loading scalar data are in italic.

Loading the parent table with a nested table column is a separate action from loading
the child nested table.
•

•

To load the parent table with a nested table column:
1.

Describe the parent table and its columns as usual, except:

2.

When describing the nested table column, this is the column that stores the
SETIDs. Its external data type is SQLT_CHR if the SETIDs in the data file are
in characters, SQLT_BIN if binary.

To load the nested table (child):
1.

Describe the nested table and its columns as usual.

2.

The SETID column is required.

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–

Set its OCI_ATTR_NAME using a dummy name (for example "setid"),
because the API does not expect you to know its system name.

–

Set the column attribute with OCI_ATTR_DIRPATH_SID to indicate that
this is a SETID column:
ub1 flg = 1;
sword error;
error = OCIAttrSet((void *)colDesc,
OCI_DTYPE_PARAM,
(void *)&flg, (ub4)0,
OCI_ATTR_DIRPATH_SID, ctlp->errhp_ctl);

This section includes the following topic: Describing a Nested Table Column and Its
Nested Table.

21.2.2 Direct Path Loading of Column Objects
A column object is a table column that is defined as an object.
Currently only the default constructor, which consists of all of the constituent attributes,
is supported.
This section includes the following topics:
•

Describing a Column Object

•

Allocating the Array Column for the Column Object

•

Loading Column Object Data into the Column Array

•

OCI_DIRPATH_COL_ERROR

21.2.2.1 Describing a Column Object
To describe a column object and its object attributes, use a direct path function
context.
Describing a column object requires setting its object constructor. Describing object
attributes is similar to describing a list of scalar columns.
To describe a column object:

Note:
•

Nested column objects are supported.

•

The steps shown here are similar to those describing a list of scalar
columns to be loaded for a table. Steps that are different from loading
scalar data are in italic.

1.

Allocate a parameter handle on the column object with OCI_DTYPE_PARAM. This
parameter handle is used to set the column's external attributes.

2.

Set the column name and its other external column attributes (for example,
maximum data size, precision, scale).

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3.

Set the external type as SQLT_NTY (named type) with OCI_ATTR_DATA_TYPE.

4.

Allocate a direct path function context handle. This context is used to describe the
column's object type and attributes:
OCIDirPathFuncCtx *dpfnctx /* direct path function context */;
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(size_t)0, (void **)0);

5.

Set the column's object type name (for example, "Employee") with
OCI_ATTR_NAME in the function context:
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
text *obj_type; /* column object's object type */
sword error;
error = OCIAttrSet((void *)dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(void *)obj_type, (ub4)strlen((const char *)obj_type),
OCI_ATTR_NAME, ctlp->errhp_ctl);

6.

Set the expression type, OCI_ATTR_DIRPATH_EXPR_TYPE, to be
OCI_DIRPATH_EXPR_OBJ_CONSTR. This indicates that the expression set with
OCI_ATTR_NAME is used as the default object constructor:
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
ub1 expr_type = OCI_DIRPATH_EXPR_OBJ_CONSTR;
sword error;
error = OCIAttrSet((void *)dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(void *)&expr_type, (ub4)0,
OCI_ATTR_DIRPATH_EXPR_TYPE,
ctlp->errhp_ctl);

7.

Set the number of columns or object attributes that are to be loaded for this
column object using OCI_ATTR_NUM_COLS.

8.

Get the column or attribute parameter list for the function context
OCIDirPathFuncCtx.

9.

For each object attribute:
a.

Get the column descriptor for the object attribute with OCI_DTYPE_PARAM.

b.

Set the attribute's column name with OCI_ATTR_NAME.

c.

Set the external column type (the type of the data that is to be passed to the
direct path API) with OCI_ATTR_DATA_TYPE.

d.

Set any other external column attributes (maximum data size, precision, scale,
and so on.)

e.

If this attribute column is a column object, then do Steps 3 through 10 for its
object attributes.

f.

Free the handle to the column descriptor.

10. Set the function context OCIDirPathFuncCtx that was created in Step 4 into the

parent column object's parameter handle with OCI_ATTR_DIRPATH_FN_CTX.

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21.2.2.2 Allocating the Array Column for the Column Object
When you direct path load a column object, the data for its object attributes is loaded
into a separate column array created just for that object.
A child column array is allocated for each column object, whether it is nested or not.
Each row of object attributes in the child column array maps to the corresponding nonNULL row of its parent column object in the parent column array.
Use the column object's direct path function context handle and function column array
value OCI_HTYPE_DIRPATH_FN_COL_ARRAY.
Example 21-18 shows how to allocate a child column array for a column object.
Example 21-18

Allocating a Child Column Array for a Column Object

OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
OCIDirPathColArray *dpfnca; /* direct path function column array */
sword error;
error = OCIHandleAlloc((void *)dpfnctx, (void **)&dpfnca,
OCI_HTYPE_DIRPATH_FN_COL_ARRAY,
(size_t)0, (void **)0);

21.2.2.3 Loading Column Object Data into the Column Array
If a column is scalar, its value is set in the column array by passing the address of its
value to OCIDirPathColArrayEntrySet().
If a column is an object, the address of its child column array handle is passed instead.
The child column array contains the data of the object attributes.
To load data into a column object:

Note:
Steps that are different from loading scalar data are in italic.

(Start.) For each column object:
1.

If the column is non-NULL:
a.

For each of its object attribute columns:
If an object attribute is a nested column object, then go to (Start.) and do this
entire procedure recursively.
Set the data in the child column array using OCIDirPathColArrayEntrySet().

b.
2.

Set the column object's data in the column array by passing the address of its
child column array handle to OCIDirPathColArrayEntrySet().

Else if the column is NULL:
Set the column object's data in the column array by passing a NULL address for
the data, a length of 0, and an OCI_DIRPATH_COL_NULL flag to
OCIDirPathColArrayEntrySet().

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See Also:
OCIDirPathColArrayEntrySet()

21.2.2.4 OCI_DIRPATH_COL_ERROR
The OCI_DIRPATH_COL_ERROR value is passed to OCIDirPathColArrayEntry() to indicate
that the current column array row should be ignored.
A typical use of this value is to back out all previous conversions for a row when an
error occurs, providing that more data for a partial column (OCI_NEED_DATA was returned
from the previous OCIDirPathColArrayToStream() call). Any previously converted data
placed in the output stream buffer for the current row is removed. Conversion then
continues with the next row in the column array. The purged row is counted in the
converted row count.
When OCI_DIRPATH_COL_ERROR is specified, the current row is ignored, as well as any
corresponding rows in any child column arrays referenced, starting from the top-level
column array row. Any NULL child column array references are ignored when moving all
referenced child column arrays to their next row.

See Also:
OCIDirPathColArrayToStream()

21.2.3 Direct Path Loading of SQL String Columns
A column value can be computed by a SQL string. SQL strings can be used for scalar
column types.
SQL strings cannot be used for object types, but can be used for object attributes of
scalar column types. They cannot be used for nested tables, sequences, and LONGs.
A SQL expression is represented to the direct path API using the OCIDirPathFuncCtx.
Its OCI_ATTR_NAME value is the SQL string with the parameter list of the named bind
variables for the expression.
The bind variable namespace is limited to a column's SQL string. The same bind
variable name can be used for multiple columns, but any arguments with the same
name only apply to the SQL string of that column.
If a SQL string of a column contains multiple references to a bind variable and multiple
arguments are specified for that name, all of the values must be the same; otherwise,
the results are undefined. Only one argument is actually required for this case, as all
references to the same bind variable name in a particular SQL expression are bound
to that single argument.
A SQL string example is:
substr(substr(:string, :offset, :length), :offset, :length)

Things to note about this example are:

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•

SQL expressions can be nested.

•

Bind variable names can be repeated within the expression.

This section includes the following topics:
•

Describing a SQL String Column

•

Allocating the Column Array for SQL String Columns

•

Loading the SQL String Data into the Column Array

21.2.3.1 Describing a SQL String Column
Lists steps for describing a SQL string column.

Note:
Steps that are different from loading scalar data are in italic.

1.

Allocate a parameter handle on the SQL string column with OCI_DTYPE_PARAM. This
parameter handle is used to set the column's external attributes.

2.

Set the column name and its other external column attributes (for example,
maximum data size, precision, scale).

3.

Set the SQL string column's external type as SQLT_NTY with
OCI_ATTR_DATA_TYPE.

4.

Allocate a direct path function context handle. This context is used to describe the
arguments of the SQL string.
OCIDirPathFuncCtx *dpfnctx /* direct path function context */;
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(size_t)0, (void **)0);

5.

Set the column's SQL string in OCI_ATTR_NAME in the function context.
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
text *sql_str; /* column's SQL string expression */
sword error;
error = OCIAttrSet((void *)dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(void *)sql_str, (ub4)strlen((const char *)sql_str),
OCI_ATTR_NAME, ctlp->errhp_ctl);

6.

Set the expression type, OCI_ATTR_DIRPATH_EXPR_TYPE, to be
OCI_DIRPATH_EXPR_SQL. This indicates that the expression set with
OCI_ATTR_NAME is used as the SQL string to derive the value from.
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
ub1 expr_type = OCI_DIRPATH_EXPR_SQL;
sword error;
error = OCIAttrSet((void *)dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,

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(void *)&expr_type, (ub4)0,
OCI_ATTR_DIRPATH_EXPR_TYPE, ctlp->errhp_ctl);
7.

Set the number of arguments that are to be passed to the SQL string with
OCI_ATTR_NUM_COLS.

8.

Get the column or attribute parameter list for the function context.

9.

For each SQL string argument:
a.

Get the column descriptor for the object attribute with OCI_DTYPE_PARAM.

b.

The order in which the SQL string arguments are defined does not matter. The
order does not have to match the order used in the SQL string.

c.

Set the attribute's column name with OCI_ATTR_NAME.

d.

Use the naming convention for SQL string arguments.

e.

The argument names must match the bind variable names used in the SQL
string in content but not in case. For example, if the SQL string is
"substr(:INPUT_STRING, 3, 5)", then it is acceptable if you give the argument
name as "input_string".

f.

If an argument is used multiple times in a SQL string, declaring it once and
counting it as one argument only is correct.

g.

Set the external column type (the type of the data that is to be passed to the
direct path API) with OCI_ATTR_DATA_TYPE.

h.

Set any other external column attributes (maximum data size, precision, scale,
and so on).

i.

Free the handle to the column descriptor.

10. Set the function context OCIDirPathFuncCtx that was created in Step 4 into the

parent column object's parameter handle with OCI_ATTR_DIRPATH_FN_CTX.

21.2.3.2 Allocating the Column Array for SQL String Columns
When you direct path load a SQL string column, the data for its arguments is loaded
into a separate column array created just for that SQL string column.
A child column array is allocated for each SQL string column. Each row of arguments
in the child column array maps to the corresponding non-NULL row of its parent SQL
string column in the parent column array.
Example 21-19 shows how to allocate a child column array for a SQL string column.
Example 21-19

Allocating a Child Column Array for a SQL String Column

OCIDirPathFuncCtx *dpfnctx;
OCIDirPathColArray *dpfnca;
sword error;

/* direct path function context */
/* direct path function column array */

error = OCIHandleAlloc((void *)dpfnctx, (void **)&dpfnca,
OCI_HTYPE_DIRPATH_FN_COL_ARRAY,
(size_t)0, (void **)0);

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21.2.3.3 Loading the SQL String Data into the Column Array
If a column is scalar, its value would be set in the column array by passing the address
of its value to OCIDirPathColArrayEntrySet().
If a column is of a SQL string type, the address of its child column array handle would
be passed instead. The child column array would contain the SQL string's argument
data.
To load data into a SQL string column:

Note:
Steps that are different from loading scalar data are in italic.

For each SQL string column:
1.

If the column is non-NULL:
For each of its function argument columns:

a.

Set the data in the child column array using OCIDirPathColArrayEntrySet().
Set the SQL string column's data into the column array by passing the address
of its child column array handle to OCIDirPathColArrayEntrySet().

b.
2.

Else if the column is NULL:
Set the SQL string column data into the column array by passing a NULL address
for the data, a length of 0, and an OCI_DIRPATH_COL_NULL flag to
OCIDirPathColArrayEntrySet().

This process is similar to that for column objects.

See Also:
•

OCI_DIRPATH_COL_ERROR for more information about passing the
OCI_DIRPATH_COL_ERROR value to OCIDirPathColArrayEntry() to indicate that
the current column array row should be ignored when an error occurs

•

OCIDirPathColArrayEntrySet()

21.2.4 Direct Path Loading of REF Columns
The REF type is a pointer, or reference, to a row object in an object table.
This section includes the following topics:
•

Describing the REF Column

•

Allocating the Column Array for a REF Column

•

Loading the REF Data into the Column Array

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21.2.4.1 Describing the REF Column
Describing the arguments to a REF column is similar to describing the list of columns to
be loaded for a table.

Note:
A REF column can be a top-table-level column or nested as an object attribute
to a column object.
Steps that are different from loading scalar data are in italic.

1.

Get a parameter handle on the REF column with OCI_DTYPE_PARAM. This parameter
handle is used to set the column's external attributes.

2.

Set the column name and its other external column attributes (for example,
maximum data size, precision, scale).

3.

Set the REF column's external type as SQLT_REF with OCI_ATTR_DATA_TYPE.

4.

Allocate a direct path function context handle. This context is used to describe the
REF column's arguments.
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(size_t)0, (void **)0);

5.

OPTIONAL: Set the REF column's table name in OCI_ATTR_NAME in the
function context. See the next step for more details.
OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
text *ref_tbl;
/* column's reference table */
sword error;
error = OCIAttrSet((void *)dpfnctx,
OCI_HTYPE_DIRPATH_FN_CTX,
(void *)ref_tbl, (ub4)strlen((const char *)ref_tbl),
OCI_ATTR_NAME, ctlp->errhp_ctl);

6.

OPTIONAL: Set the expression type, OCI_ATTR_DIRPATH_EXPR_TYPE, to be
OCI_DIRPATH_EXPR_REF_TBLNAME. Set this only if Step 5 was done. This
indicates that the expression set with OCI_ATTR_NAME is to be used as the
object table to reference row objects from. This parameter is optional. The
behavior for this parameter varies for the REF type.
•

Unscoped REF columns (unscoped, system-OID-based):
If not set, then by the definition of an "unscoped" REF column, this REF
column is required to have a reference table name as its argument for every
data row.
If set, this REF column can only refer to row objects from this specified object
table for the duration of the load. And the REF column is not allowed to have a
reference table name as its argument. (The direct path API is providing this

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parameter as a shortcut to users who will be loading to an unscoped REF
column that refers to the same reference object table during the entire load.)
•

Scoped REF columns (scoped, system-OID-based, and primary-key-based):
If not set, the direct path API uses the reference table specified in the schema.
If set, the reference table name must match the object table specified in the
schema for this scoped REF column. An error occurs if the table names do not
match.
Whether this parameter is set or not, it does not matter to the API whether this
reference table name is in the data row or not. If the name is in the data row, it
must match the table name specified in the schema. If it is not in the data row,
the API uses the reference table specified in the schema.

7.

Set the number of REF arguments that are to be used to reference a row object
with OCI_ATTR_NUM_COLS. The number of arguments required varies for the
REF column type. This number is derived from Step 6 earlier.
•

Unscoped REF columns (unscoped, system-OID-based REF columns):
One if OCI_DIRPATH_EXPR_REF_TBLNAME is used. None for the reference
table name, and one for the OID value.
Two if OCI_DIRPATH_EXPR_REF_TBLNAME is not used. One for the
reference table name, and one for the OID value.

•

Scoped REF columns (scoped, system-OID-based, and primary-key-based):
N or N+1 are acceptable, where N is the number of columns making up the
object ID, regardless if OCI_DIRPATH_EXPR_REF_TBLNAME is used or not.
Minimum is N if the reference table name is not in the data row. It is N+1 if the
reference table name is in the data row. Note: If the REF is system-OIDbased, then N is one. If the REF is primary-key-based, then N is the number of
component columns that make up the primary key. If the reference table name
is in the data row, then add one to N.

Note:
To simplify the error message if you pass in some REF arguments
other than N or N+1, the error message says that it found so-and-so
number of arguments when it expects N. Although N+1 is not stated
in the message, N+1 is acceptable (even though the reference table
name is not needed) and does not invoke an error message.
8.

Get the column or attribute parameter list for the function context.

9.

For each REF argument or attribute:
a.

Get the column descriptor for the REF argument using OCI_DTYPE_PARAM.

b.

Set the attribute's column name using OCI_ATTR_NAME.
The order of the REF arguments given matter. The reference table name
comes first, if given. The object ID, whether it is system-generated or primarykey-based, comes next.
There is a naming convention for the REF arguments. Because the reference
table name is not a table column, you can use any dummy names for its
column name, such as "ref-tbl." For a system-generated OID column, you can

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use any dummy names for its column name, such as "sys-OID". For a primarykey-based object ID, list all the primary-key columns to load into. There is no
need to create a dummy name for OID. The component column names, if
given (see shortcut note later), can be given in any order.
Do not set the attribute column names for the object ID to use the shortcut.
Shortcut. If loading a system-OID-based REF column, do not set the column
name with a name. The API figures it out. But you must still set other column
attributes, such as external data type.
If loading a primary-key REF column and its primary key consists of multiple
columns, the shortcut is not to set their column names. But you must still set
other column attributes, such as external data type.

Note:
If the component column names are NULL, then the API code
determines the column names in the position or order in which they
were defined for the primary key. So, when you set column attributes
other than the name, ensure that the attributes are set for the
component columns in the correct order.
c.

Set the external column type (the type of the data that is to be passed to the
direct path API) using OCI_ATTR_DATA_TYPE.

d.

Set any other external column attributes (max data size, precision, scale, and
so on).

e.

Free the handle to the column descriptor.

f.

Set the function context OCIDirPathFuncCtx that was created in Step 4 in the
parent column object's parameter handle using
OCI_ATTR_DIRPATH_FN_CTX.

21.2.4.2 Allocating the Column Array for a REF Column
Shows how to allocate a child column array for a REF column.
Example 21-20 shows how to allocate a child column array for a REF column.
Example 21-20

Allocating a Child Column Array for a REF Column

OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
OCIDirPathColArray *dpfnca; /* direct path function column array */
sword error;
error = OCIHandleAlloc((void *)dpfnctx, (void **)&dpfnca,
OCI_HTYPE_DIRPATH_FN_COL_ARRAY,
(size_t)0, (void **)0);

21.2.4.3 Loading the REF Data into the Column Array
If a column is scalar, its value is set in the column array by passing the address of its
value to OCIDirPathColArrayEntrySet().
If a column is a REF, the address of its child column array handle is passed instead.
The child column array contains the REF arguments' data.

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To load data into a REF column:

Note:
Steps that are different from loading scalar data are in italic.

For each REF column:
1.

If the column is non-NULL:
a.

For each of its REF argument columns:
Set its data in the child column array using OCIDirPathColArrayEntrySet().

b.
2.

Set the REF column's data into the column array by passing the address of its
child column array handle to OCIDirPathColArrayEntrySet().

Else if the column is NULL:
Set the REF column's data into the column array by passing a NULL address for the
data, a length of 0, and an OCI_DIRPATH_COL_NULL flag to
OCIDirPathColArrayEntrySet().

See Also:
•

OCI_DIRPATH_COL_ERROR

•

OCIDirPathColArrayEntrySet()

21.2.5 Direct Path Loading of NOT FINAL Object and REF Columns
Recall that SQL object inheritance is based on a family tree of object types that forms
a type hierarchy.
The type hierarchy consists of a parent object type, called a supertype, and one or
more levels of child object types, called subtypes, which are derived from the parent.
This section includes the following topics:
•

Inheritance Hierarchy

•

About Describing a Fixed, Derived Type to Be Loaded

•

About Allocating the Column Array

•

About Loading the Data into the Column Array

21.2.5.1 Inheritance Hierarchy
Recall that for an object type to be inheritable, the object type definition must specify
that it is inheritable.
Figure 21-2 diagrams the inheritance hierarchy for a column of type Person. The Person
supertype is at the top of the hierarchy with two attributes: Name, Address. Person has
two subtypes, Employee and Student. The Employee subtype has two attributes: Manager,

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Deptid. The Student subtype has two attributes: Units, GPA. ParttimeEmployee is a
subtype of Employee and appears below it. The subtype ParttimeEmployee has one
attribute: Hours. These are the types that can be stored in a Person column.

Figure 21-2

Inheritance Hierarchy for a Column of Type Person

Once specified, subtypes can be derived from it. To specify an object to be inheritable,
the keyword NOT FINAL must be specified in its type definition. To specify an object to
not be inheritable, the keyword FINAL must be specified in its type definition.
When you direct path load a table that contains a column of type Person, the actual set
of types could include any of these four: the NOT FINAL type Person, and its three
subtypes: Student, Employee, and ParttimeEmployee. Because the direct path load API
only supports the loading of one fixed, derived type to this NOT FINAL column for the
duration of this load, the direct path load API must know which one of these types is to
be loaded, the attributes to load for this type, and the function used to create this type.
So when you describe and load a derived type, you must specify all of the attributes
for that type that are to be loaded. Think of a subtype as a flattened representation of
all the object attributes that are unique to this type, plus all the attributes of its
ancestors. Therefore, any of these attribute columns that are to be loaded into, you
must describe and count.
For example, to load all columns in ParttimeEmployee, you must describe and count five
object attributes to load into: Name, Address, Manager, Deptid, and Hours.

See Also:
Oracle Database Object-Relational Developer's Guide for more information
about defining FINAL and NOT FINAL types.

21.2.5.2 About Describing a Fixed, Derived Type to Be Loaded
Note that the steps to describe a NOT FINAL or substitutable object columns and REF
columns of a fixed, derived type are similar to the steps that describe its FINAL
counterpart.
These sections describe a FINAL column of this type. Because the derived type (could
be a supertype or a subtype) is fixed for the duration of the load, the client interface for
describing a NOT FINAL column is the same as for describing a FINAL column.

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A subtype can be thought of as a flattened representation of all the object attributes
that are unique to this type plus all the attributes of its ancestors. Therefore, any of
these attribute columns that are to be loaded into must be described and counted.

See Also:
Direct Path Loading of Column Objects or Direct Path Loading of REF
Columns for information about how to describe a NOT FINAL column of type X
(where X is an object or a REF)

21.2.5.3 About Allocating the Column Array
Indicates it is the same as for a FINAL column of the same type.
Allocating the column array is the same as for a FINAL column of the same type.

21.2.5.4 About Loading the Data into the Column Array
Indicates it is the same as for a FINAL column of the same type.
Loading the data into the column array is the same as for a FINAL column of the same
type.

21.2.6 Direct Path Loading of Object Tables
An object table is a table in which each row is an object (or row object). Each column
in the table is an object attribute.
Describing an Object Table
Describing an object table is very similar to describing a non-object table. Each object
attribute is a column in the table. The only difference is that you may need to describe
the OID, which could be system-generated, user-generated, or primary-key-based.
To describe an object table:

Note:
Steps that are different from loading a non-object table are in italic.

For each object attribute column:
Describe each object attribute column as it must be described, depending on its type
(for example, NUMBER, REF):
For the object table OID (Oracle Internet Directory):
1.

If the object ID is system-generated:
There is nothing extra to do. The system generates OIDs for each row object.

2.

If the object ID is user-generated:

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3.

a.

Use a dummy name to represent the column name for the OID (for example,
"cust_oid").

b.

Set the OID column attribute with OCI_ATTR_DIRPATH_OID.

If the object ID is primary-key-based:
a.

Load all of the primary-key columns making up the OID.

b.

Do not set OCI_ATTR_DIRPATH_OID, because no OID column with a dummy
name was created.

Allocating the Column Array for the Object Table
Example 21-21 shows that allocating the column array for the object table is the same
as allocating a column array for a non-object table.
Loading Data into the Column Array
Loading data into the column array is the same as loading data into a non-object table.
Example 21-21

Allocating the Column Array for the Object Table

OCIDirPathColArray *dpca; /* direct path column array */
sword error;
error = OCIHandleAlloc((void *)dpctx, (void **)&dpca,
OCI_HTYPE_DIRPATH_COLUMN_ARRAY,
(size_t)0, (void **)0);

21.2.7 Direct Path Loading a NOT FINAL Object Table
A NOT FINAL object table supports inheritance and a FINAL object table cannot.
Describing a NOT FINAL Object Table
Describing a NOT FINAL object table of a fixed derived type is very similar to describing
a FINAL object table.
To describe a NOT FINAL object table of a fixed derived type:

Note:
Steps that are different from describing a FINAL object table are in italic.

1.

Set the object table's object type in the direct path context with
OCI_ATTR_DIRPATH_OBJ_CONSTR. This indicates that the object type,
whether it is a supertype or a derived type, are used as the default object
constructor when loading to this table for the duration of the load.
text *obj_type;

/* the object type to load into this NOT FINAL */
/* object table */

sword error;
error = OCIAttrSet((void *)dpctx,
OCI_HTYPE_DIRPATH_CTX,
(void *) obj_type,

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(ub4)strlen((const char *) obj_type),
OCI_ATTR_DIRPATH_OBJ_CONSTR, ctlp->errhp_ctl);
2.

Describe according to its data type each of the object attribute columns to be
loaded. Describe the object ID, if needed. This is the same as describing a FINAL
object table.

Allocating the Column Array for the NOT FINAL Object Table
Allocating the column array for the NOT FINAL object table is the same as for a FINAL
object table.

21.3 Direct Path Loading in Pieces
To support loading data that does not all fit in memory at one time, use loading in
pieces.
The direct path API supports loading LONGs and LOBs incrementally. This is
accomplished through the following steps:
1.

Set the first piece into the column array using OCIDirPathColArrayEntrySet() and
passing in the OCI_DIRPATH_COL_PARTIAL flag to indicate that all the data for this
column has not been loaded yet.

2.

Convert the column array to a stream.

3.

Load the stream.

4.

Set the next piece of that data into the column array. If it is not complete, set the
partial flag and go back to Step 2. If it is complete, then set the
OCI_DIRPATH_COL_COMPLETE flag and continue to the next column.

This approach is essentially the same for dealing with large attributes for column
objects and large arguments for SQL string types.

Note:
Collections are not loaded in pieces, as such. Nested tables are loaded
separately and are loaded like a top-level table. Nested tables can be loaded
incrementally and can have columns that are loaded in pieces. Therefore, do
not set the OCI_DIRPATH_COL_PARTIAL flag for the column containing the
collection.
This section includes the following topic: Loading Object Types in Pieces.

See Also:
•

OCI_DIRPATH_COL_ERROR for more information about passing the
OCI_DIRPATH_COL_ERROR value to OCIDirPathColArrayEntry() to indicate that
the current column array row should be ignored when an error occurs

•

OCIDirPathColArrayEntrySet()

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21.3.1 Loading Object Types in Pieces
Objects are loaded into a separate column array from the parent table that contains
them.
Therefore, when they need to be loaded in pieces you must set the elements in the
child column array up to and including the pieced element.
The general steps are:
1.

For the pieced element, set the OCI_DIRPATH_COL_PARTIAL flag.

2.

Set the child column array handle into the parent column array and mark that entry
with the OCI_DIRPATH_COL_PARTIAL flag as well.

3.

Convert the parent column array to a stream. This converts the child column array
as well.

4.

Load the stream.

5.

Go back to Step 1 and continue loading the remaining data for that element until it
is complete.

Here are some rules about loading in pieces:
•

There can only be one partial element at a time at any level. Once one partial
element is marked complete, then another one at that level can be partial.

•

If an element is partial and it is not top-level, then all of its ancestors up the
containment hierarchy must be marked partial as well.

•

If there are multiple levels of nesting, it is necessary to go up to a level where the
data can be converted into a stream. This is a top-level table.

See Also:
OCI_DIRPATH_COL_ERROR for more information about passing the
OCI_DIRPATH_COL_ERROR value to OCIDirPathColArrayEntry() to indicate that the

current column array row should be ignored when an error occurs.

21.4 Direct Path Context Handles and Attributes for Object
Types
The following discussion gives the supplemental details of the handles and attributes.
This section includes the following topics:
•

Direct Path Context Attributes

•

Direct Path Function Context and Attributes

•

Direct Path Column Parameter Attributes

•

Direct Path Function Column Array Handle for Nonscalar Columns

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See Also:
Handle and Descriptor Attributes for a discussion that gives the supplemental
details of the handles and attributes

21.4.1 Direct Path Context Attributes
There is one direct path context attribute.

See Also:
OCI_ATTR_DIRPATH_OBJ_CONSTR is the only direct path context
attribute

21.4.1.1 OCI_ATTR_DIRPATH_OBJ_CONSTR
Indicates the object type to load into a NOT FINAL object table.
ttext *obj_type;

/* the object type to load into this NOT FINAL */
/* object table */

sword error;
error = OCIAttrSet((void *)dpctx,
OCI_HTYPE_DIRPATH_CTX,
(void *) obj_type,
(ub4)strlen((const char *) obj_type),
OCI_ATTR_DIRPATH_OBJ_CONSTR, ctlp->errhp_ctl);

21.4.2 Direct Path Function Context and Attributes
Here is a summary of the attributes for function context handles.
This section includes the following topics:
•

OCI_ATTR_DIRPATH_OBJ_CONSTR

•

OCI_ATTR_NAME

•

OCI_ATTR_DIRPATH_EXPR_TYPE

•

OCI_ATTR_DIRPATH_NO_INDEX_ERRORS

•

OCI_ATTR_NUM_COLS

•

OCI_ATTR_NUM_ROWS

See Also:
Direct Path Context Handle (OCIDirPathCtx) Attributes

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21.4.2.1 OCI_ATTR_DIRPATH_OBJ_CONSTR
Indicates the object type to load into a substitutable object table.
text *obj_type; /* stores an object type name */
sword error;
error = OCIAttrSet((void *)dpctx,
OCI_HTYPE_DIRPATH_CTX,
(void *) obj_type,
(ub4)strlen((const char *) obj_type),
OCI_ATTR_DIRPATH_OBJ_CONSTR, ctlp->errhp_ctl);

21.4.2.2 OCI_ATTR_NAME
When a function context is created, set OCI_ATTR_NAME equal to the expression that
describes the nonscalar column.
Then set an OCI attribute to indicate the type of the expression. The expression type
varies depending on whether it is a column object, a REF column, or a SQL string
column.
Column Objects
This required expression is the object type name. The object type is used as the
default object constructor.
Set the expression type OCI_ATTR_DIRPATH_EXPR_TYPE to OCI_DIRPATH_EXPR_OBJ_CONSTR to
indicate that this expression is an object type name.
REF Columns
This optional expression is the reference table name. This table is the object table
from which the REF column is to reference row objects.
Set the expression type OCI_ATTR_DIRPATH_EXPR_TYPE to OCI_DIRPATH_EXPR_REF_TBLNAME to
indicate that this expression is a reference object table.
The behavior for this parameter, set or not set, varies for each REF type.
•

•

Unscoped REF columns (unscoped, system-OID-based):
–

If not set, then by the definition of an "unscoped" REF column, this REF column
must have a reference table name as its argument for every data row.

–

If set, this REF column can only refer to row objects from this specified object
table for the duration of the load. The REF column is not allowed to have a
reference table name as its argument. (Direct path API provides this
parameter as a shortcut for the users who will be loading to an unscoped REF
column that refers to the same reference object table during the entire load.)

Scoped REFcolumns (scoped, system-OID-based and primary-key-based):
–

If not set, the direct path API uses the reference table specified in the schema.

–

If set, the reference table name must match the object table specified in the
schema for this scoped REF column. An error occurs if the table names do not
match.

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–

Whether this parameter is set or not, it does not matter to the API whether this
reference table name is in the data row or not. If the name is in the data row, it
must match the table name specified in the schema. If it is not in the data row,
the API uses the reference table defined in the schema.

SQL String Columns
This mandatory expression contains a SQL string to derive the value that is to be
stored in the column.
Set the expression type OCI_ATTR_DIRPATH_EXPR_TYPE to OCI_DIRPATH_EXPR_SQL to indicate
that this expression is a SQL string.

21.4.2.3 OCI_ATTR_DIRPATH_EXPR_TYPE
This attribute is used to indicate the type of the expression specified in OCI_ATTR_NAME
for the nonscalar column's function context.
If OCI_ATTR_NAME is set, then OCI_ATTR_DIRPATH_EXPR_TYPE is required.
The possible values for OCI_ATTR_DIRPATH_EXPR_TYPE are:
•

•

•

OCI_DIRPATH_EXPR_OBJ_CONSTR

–

Indicates that the expression is an object type name and is to be used as the
default object constructor for a column object.

–

Is required for column objects.

OCI_DIRPATH_EXPR_REF_TBLNAME

–

Indicates that the expression is a reference object table name. This table is the
object table from which the REF column is referencing row objects.

–

Is optional for REF columns.

OCI_DIRPATH_EXPR_SQL

–

Indicates that the expression is a SQL string that is executed to derive a value
to be stored in the column.

–

Is required for SQL string columns.

Example 21-22 shows the pseudocode that illustrates the preceding rules and values.
Example 21-22
Attribute

Specifying Values for the OCI_ATTR_DIRPATH_EXPR_TYPE

OCIDirPathFuncCtx *dpfnctx; /* function context for this nonscalar column */
ub1 expr_type; /* expression type */
sword error;
if (...) /* (column type is an object) */
expr_type = OCI_DIRPATH_EXPR_OBJ_CONSTR;
...
if (...) /* (column type is a REF && function context name exists) */
expr_type = OCI_DIRPATH_EXPR_REF_TBLNAME;
...
if (...) /* (column type is a SQL string) */
expr_type = OCI_DIRPATH_EXPR_SQL;
...
error = OCIAttrSet((void *)(dpfnctx),
OCI_HTYPE_DIRPATH_FN_CTX,

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(void *)&expr_type, (ub4)0,
OCI_ATTR_DIRPATH_EXPR_TYPE, ctlp->errhp_ctl);

21.4.2.4 OCI_ATTR_DIRPATH_NO_INDEX_ERRORS
When OCI_ATTR_DIRPATH_NO_INDEX_ERRORS is 1, indexes are not set unusable at any time
during the load.
If any index errors are detected, the load is terminated. That is, no rows are loaded,
and the indexes are left as is. The default is 0.

See Also:
OCI_ATTR_DIRPATH_NO_INDEX_ERRORS

21.4.2.5 OCI_ATTR_NUM_COLS
This attribute describes the number of attributes or arguments that are to be loaded or
processed for a nonscalar column.
This parameter must be set before the column list can be retrieved. The expression
type varies depending on whether it is a column object, a SQL string column, or a REF
column.
Column Objects
The number of object attribute columns to be loaded for this column object.
SQL String Columns
The number of arguments to be passed to the SQL string.
If an argument is used multiple times in the function, counting it as one is correct.
REF Columns
The number of REF arguments to identify the row object the REF column should point to.
The number of arguments required varies for the REF column type:
•

•

Unscoped REF columns (unscoped, system-OID-based REF columns):
–

If OCI_DIRPATH_EXPR_REF_TBLNAME is used. None for the reference table name,
and one for the OID value. (Only the OID values are in the data rows.)

–

If OCI_DIRPATH_EXPR_REF_TBLNAME is not used. One for the reference table name,
and one for the OID value. (Both the reference table names and the OID
values are in the data rows.)

Scoped REF columns (scoped, system-OID-based and primary-key-based):
–

N or N+1 are acceptable, where N is the number of columns making up the
object ID, regardless if OCI_DIRPATH_EXPR_REF_TBLNAME is used or not. The
minimum is N if the reference table name is not in the data row. Use N+1 if the
reference table name is in the data row.

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–

If the REF is system-OID-based, then N is 1. If the REF is primary-key-based,
then N is the number of component columns that make up the primary key. If
the reference table name is in the data row, then add 1 to N.

Note:
To simplify the error message if you pass in some REF arguments other
than N or N+1, the error message says that it found so-and-so number of
arguments when it expects N. Although N+1 is not stated in the
message, N+1 is acceptable (even though the reference table name is
not needed) and does not invoke an error message.

21.4.2.6 OCI_ATTR_NUM_ROWS
This attribute, when used for an OCI_HTYPE_DIRPATH_FN_CTX (function context), is
retrievable only, and cannot be set by the user.
You can only use this attribute in OCIAttrGet() and not OCIAttrSet(). When
OCIAttrGet() is called with OCI_ATTR_NUM_ROWS, the number of rows loaded so
far is returned.
However, the attribute OCI_ATTR_NUM_ROWS, when used for an OCI_HTYPE_DIRPATH_CTX
(table-level context), can be both set and retrieved by the user.
Calling OCIAttrSet() with OCI_ATTR_NUM_ROWS and OCI_HTYPE_DIRPATH_CTX sets the
number of rows to be allocated for the table-level column array. If not set, the direct
path API code derives a "reasonable" number based on the maximum record size and
the transfer buffer size. To see how many rows were allocated, call OCIAttrGet() with
OCI_ATTR_NUM_ROWS on OCI_HTYPE_DIRPATH_COLUMN_ARRAY for a table-level column array,
and with OCI_HTYPE_DIRPATH_FN_COL_ARRAY for a function column array.
Calling OCIAttrGet() with OCI_ATTR_NUM_ROWS and OCI_HTYPE_DIRPATH_CTX returns the
number of rows loaded so far.
This attribute cannot be set by the user for a function context. You are not allowed to
specify the number of rows desired in a function column array through
OCI_ATTR_NUM_ROWS with OCIAttrSet() because then all function column arrays will have
the same number of rows as the table-level column array. Thus this attribute can only
be set for a table-level context and not for a function context.

See Also:
•

OCIAttrGet()

•

OCIAttrSet()

21.4.3 Direct Path Column Parameter Attributes
When you describe an object, SQL string, or REF column, one of its column attributes is
a function context.

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If a column is an object, then its function context describes its object type and object
attributes. If the column is a SQL string, then its function context describes the
expression to be called. If the column is a REF, its function context describes the
reference table name and row object identifiers.
Example 21-23 shows that when you set a function context as a column attribute,
OCI_ATTR_DIRPATH_FN_CTX is used in the OCIAttrSet() call.
Attributes for column parameter context handles follow.
Example 21-23

Setting a Function Context as a Column Attribute

OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
sword error;
error = OCIAttrSet((void *)colDesc,
OCI_DTYPE_PARAM,
(void *)(dpfnctx), (ub4)0,
OCI_ATTR_DIRPATH_FN_CTX, ctlp->errhp_ctl);

This section includes the following topics:
•

OCI_ATTR_NAME

•

OCI_ATTR_DIRPATH_SID

•

OCI_ATTR_DIRPATH_OID

See Also:
•

Direct Path Column Parameter Attributes

•

OCIAttrSet()

21.4.3.1 OCI_ATTR_NAME
The naming conventions for loading nested tables, object tables, SQL string columns,
and REF columns are described in the following paragraphs.
In general, a dummy column name is used if you are loading data into a column that is
a system column with a system name that you are not aware of (for example, an
object table's system-generated object ID (OID) column or a nested table's SETID (SID)
column) or if a column is an argument that does not have a database table column (for
example, SQL string and REF arguments).
If the column is a database table column but a dummy name was used, then a column
attribute must be set so that the function can identify the column even though it is not
under the name known to the database.
The naming rules are as follows:
•

Child nested table's SETID (SID) column
The SETID column is required. Set its OCI_ATTR_NAME using a dummy name,
because the API does not expect the user to know its system name. Then set the
column attribute with OCI_ATTR_DIRPATH_SID to indicate that this is a SID column.

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•

Object table's object ID (OID) column
An object ID is required if:
1.

The object ID is system-generated:
Use a dummy name as its column name (for example, "cust_oid").
Set its column attribute with OCI_ATTR_DIRPATH_OID. So if you have multiple
columns with dummy names, you know which one represents the systemgenerated OID.

2.

The object id is primary-key-based:
You cannot use a dummy name as its column name. Therefore, you do not
need to set its column attribute with OCI_ATTR_DIRPATH_OID.

•

•

SQL string argument
1.

Set the attribute's column name with OCI_ATTR_NAME.

2.

The order of the SQL string arguments given does not matter. The order does
not have to match the order used in the SQL string.

3.

Use the naming convention for SQL string arguments.
–

The argument names must match the bind variable names used in the
SQL string in content but not in case. For example, if the SQL string is
substr(:INPUT_STRING, 3, 5), then you can give the argument name as
"input_string".

–

If an argument is used multiple times in an SQL string, then you can
declare it once and count it as only one argument.

REF argument
1.

Set the attribute's column name using OCI_ATTR_NAME.
The order of the REF arguments does matter.

2.

3.

–

The reference table name comes first, if given.

–

The object ID, whether it is system-generated or primary-key-based,
comes next.

Use the naming convention for the REF arguments.
–

For the reference table name argument, use any dummy name for its
column name, for example, "ref-tbl."

–

For the system-generated OID argument, use any dummy name for its
column name, such as "sys-OID." Note: Because this column is used as
an argument and not as a column to load into, do not set this column with
OCI_ATTR_DIRPATH_OID.

–

For a primary-key-based object ID, list all the primary-key columns to load
into. There is no need to create a dummy name for OID. The component
column names, if given (see step for shortcut later), can be given in any
order.

Do not set the attribute column names for the object ID to use the shortcut.
–

Shortcut. If loading a system-OID-based REF column, do not set the
column name with a name. The API figures it out. But you must still set
other column attributes, such as external data type.

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–

If loading a primary-key REF column and its primary key consists of multiple
columns, the shortcut is not to set their column names. However, you
must set other column attributes, such as the external data type.

Note:
If the component column names are NULL, then the API code
determines the column names in the position or order in which
they were defined for the primary key. So, when you set column
attributes other than the name, ensure that the attributes are set
for the component columns in the correct order.

21.4.3.2 OCI_ATTR_DIRPATH_SID
Indicates that a column is a nested table's SETID column. Required if loading to a
nested table.
ub1 flg = 1;
sword error;
error = OCIAttrSet((void *)colDesc,
OCI_DTYPE_PARAM,
(void *)&flg, (ub4)0,
OCI_ATTR_DIRPATH_SID, ctlp->errhp_ctl);

21.4.3.3 OCI_ATTR_DIRPATH_OID
Indicates that a column is an object table's object ID column.
ub1 flg = 1;
sword error;
error = OCIAttrSet((void *)colDesc,
OCI_DTYPE_PARAM,
(void *)&flg, (ub4)0,
OCI_ATTR_DIRPATH_OID, ctlp->errhp_ctl);

21.4.4 Direct Path Function Column Array Handle for Nonscalar
Columns
The handle type OCI_HTYPE_DIRPATH_FN_COL_ARRAY is used if the column is an object,
SQL string, or REF.
The structure OCIDirPathColArray is the same for both scalar and nonscalar columns.
Example 21-24 shows how to allocate a child column array for a function context.
Example 21-24

Allocating a Child Column Array for a Function Context

OCIDirPathFuncCtx *dpfnctx; /* direct path function context */
OCIDirPathColArray *dpfnca; /* direct path function column array */
sword error;
error = OCIHandleAlloc((void *)dpfnctx, (void **)&dpfnca,

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OCI_HTYPE_DIRPATH_FN_COL_ARRAY,
(size_t)0, (void **)0);

This section includes the following topic: OCI_ATTR_NUM_ROWS Attribute.

See Also:
Direct Path Function Column Array Handle (OCIDirPathColArray) Attributes

21.4.4.1 OCI_ATTR_NUM_ROWS Attribute
This attribute, when used for an OCI_HTYPE_DIRPATH_FN_COL_ARRAY (function column
array), is retrievable only, and cannot be set by the user.
When the OCI_ATTR_NUM_ROWS attribute is called with the function OCIAttrGet(), the
number of rows allocated for the function column array is returned.

See Also:
OCIAttrGet()

21-42

22
Object Advanced Topics in OCI
This chapter introduces the OCI facility for working with objects in an Oracle Database.
It also discusses the object navigational function calls, type evolution, and support for
XML produced by OCI.
This chapter contains these topics:
•

Object Cache and Memory Management

•

Object Navigation

•

OCI Navigational Functions

•

Type Evolution and the Object Cache

22.1 Object Cache and Memory Management
The object cache is a client-side memory buffer that provides lookup and memory
management support for objects.
It stores and tracks object instances that have been fetched by an OCI application.
The object cache provides memory management.
When objects are fetched by the application through a SQL SELECT statement, or
through an OCI pin operation, a copy of the object is stored in the object cache.
Objects that are fetched directly through a SELECT statement are fetched by value, and
they are nonreferenceable objects that cannot be pinned. Only referenceable objects
can be pinned.
If an object is being pinned, and an appropriate version exists in the cache, it does not
need to be fetched from the server.
Every client program that uses OCI to dereference REFs to retrieve objects utilizes the
object cache. A client-side object cache is allocated for every OCI environment handle
initialized in object mode. Multiple threads of a process can share the same client-side
cache by sharing the same OCI environment handle.
Exactly one copy of each referenceable object exists in the cache for each connection.
The object cache is logically partitioned by the connection.
Dereferencing a REF many times or dereferencing several equivalent REFs in the same
connection returns the same copy of the object.
If you modify a copy of an object in the cache, you must flush the changes to the
server before they are visible to other processes. Objects that are no longer needed
can be unpinned or freed; they can then be swapped out of the cache, freeing the
memory space they occupied.
When database objects are loaded into the cache, they are transparently mapped into
the C language structures. The object cache maintains the association between all
object copies in the cache and their corresponding objects in the database. When the

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transaction is committed, changes made to the object copy in the cache are
automatically propagated to the database.
The cache does not manage the contents of object copies; it does not automatically
refresh object copies. The application must ensure the correctness and consistency of
the contents of object copies. For example, if the application marks an object copy for
insert, update, or delete, and then terminates the transaction, the cache simply
unmarks the object copy but does not purge or invalidate the copy. The application
must pin recent or latest, or refresh the object copy in the next transaction. If it pins
any, it may get the same object copy with its uncommitted changes from the previous
terminated transaction.
The object cache is created when the OCI environment is initialized using
OCIEnvCreate() with mode set to OCI_OBJECT.
The object cache maintains a fast lookup table for mapping REFs to objects. When an
application dereferences a REF and the corresponding object is not yet cached in the
object cache, the object cache automatically sends a request to the server to fetch the
object from the database and load it into the object cache.
Subsequent dereferences of the same REF are faster because they use local cache
access and do not incur network round-trips. To notify the object cache that an
application is accessing an object in the cache, the application pins the object; when it
is done with the object, it should unpin it. The object cache maintains a pin count for
each object in the cache; the count is incremented upon a pin call, and an unpin call
decrements it. The pin count goes to zero when the object is no longer needed by the
application.
The object cache uses a least recently used (LRU) algorithm to manage the size of the
cache. The LRU algorithm frees candidate objects when the cache reaches the
maximum size. The candidate objects are objects with a pin count of zero.
Each application process running against the same server has its own object cache,
as shown in Figure 22-1.

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Object Cache and Memory Management

Figure 22-1

Object Cache
Application 1
Object Cache

Application 2
Object Cache

System Global
Area (SGA)

Oracle
Database

The object cache tracks the objects that are currently in memory, maintains references
to the objects, manages automatic object swapping, and tracks object meta-attributes.
This section includes the following topics:
•

Cache Consistency and Coherency

•

Object Cache Parameters

•

Object Cache Operations

•

About Loading and Removing Object Copies

•

About Making Changes to Object Copies

•

About Synchronizing Object Copies with the Server

•

Object Locking

•

Commit and Rollback in Object Applications

•

Object Duration

•

Memory Layout of an Instance

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See Also:
•

About Pinning an Object Copy

•

OCIEnvCreate()

22.1.1 Cache Consistency and Coherency
The object cache does not automatically maintain value coherency or consistency
between object copies and their corresponding objects in the database.
In other words, if an application makes changes to an object copy, the changes are not
automatically applied to the corresponding object in the database, and vice versa. The
cache provides operations such as flushing a modified object copy to the database
and refreshing a stale object copy with the latest value from the database to enable
the program to maintain some coherency.

Note:
Oracle Database does not support automatic cache coherency with the
server's buffer cache or database. Automatic cache coherency refers to the
mechanism by which the object cache refreshes local object copies when the
corresponding objects have been modified in the server's buffer cache. This
mechanism occurs when the object cache flushes the changes made to local
object copies to the buffer cache before any direct access of corresponding
objects in the server. Direct access includes using SQL, triggers, or stored
procedures to read or modify objects in the server.

22.1.2 Object Cache Parameters
The object cache has two important parameters associated with it, which are attributes
of the environment handle.
They include:
•

OCI_ATTR_CACHE_MAX_SIZE – The maximum cache size

•

OCI_ATTR_CACHE_OPT_SIZE – The optimal cache size

These parameters refer to levels of cache memory usage, and they help determine
when the cache automatically ages out eligible objects to free up memory.
If the memory occupied by the objects currently in the cache reaches or exceeds the
maximum cache size, the cache automatically begins to free (or ages out) unmarked
objects that have a pin count of zero. The cache continues freeing such objects until
memory usage in the cache reaches the optimal size, or until it runs out of objects
eligible for freeing. Note that the cache can grow beyond the specified maximum
cache size.
OCI_ATTR_CACHE_MAX_SIZE is specified as a percentage of OCI_ATTR_CACHE_OPT_SIZE. The
maximum object cache size (in bytes) is computed by incrementing

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OCI_ATTR_CACHE_OPT_SIZE by the OCI_ATTR_CACHE_MAX_SIZE percentage, using the

following algorithm:
maximum_cache_size = optimal_size + optimal_size * max_size_percentage / 100

Next, represent the algorithm in terms of environment handle attributes.
maximum_cache_size = OCI_ATTR_CACHE_OPT_SIZE + OCI_ATTR_CACHE_OPT_SIZE *
OCI_ATTR_CACHE_MAX_SIZE / 100

You can set the value of OCI_ATTR_CACHE_MAX_SIZE at 10% (the default) of the
OCI_ATTR_CACHE_OPT_SIZE. The default value for OCI_ATTR_CACHE_OPT_SIZE is 8 MB.
The cache size attributes of the environment handle can be set with the OCIAttrSet()
call and retrieved with the OCIAttrGet() function.

See Also:
•

Environment Handle Attributes for more information

•

OCIAttrSet()

•

OCIAttrGet()

22.1.3 Object Cache Operations
This section describes the most important functions that the object cache provides to
operate on object copies.
This section includes the following topics:
•

About Pinning and Unpinning

•

About Freeing

•

About Marking and Unmarking

•

About Flushing

•

About Refreshing

See Also:
OCI Navigational Functions for a list of all the OCI navigational, cache, and
object management functions

22.1.3.1 About Pinning and Unpinning
Pinning an object copy enables the application to access it in the cache by
dereferencing the REF to it.

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Unpinning an object indicates to the cache that the object currently is not being used.
Objects should be unpinned when they are no longer needed to make them eligible for
implicit freeing by the cache, thus freeing up memory.

22.1.3.2 About Freeing
What about freeing an object. What does it do.
Freeing an object copy removes it from the cache and frees its memory.

22.1.3.3 About Marking and Unmarking
Marking an object notifies the cache that an object copy has been updated in the
cache and the corresponding object must be updated in the server when the object
copy is flushed.
Unmarking an object removes the indication that the object has been updated.

22.1.3.4 About Flushing
Flushing an object writes local changes made to marked object copies in the cache to
the corresponding objects in the server.
When this happens, the copies in the object cache are unmarked.

22.1.3.5 About Refreshing
Refreshing an object copy in the cache replaces it with the latest value of the
corresponding object in the server.
Note that pointers to top-level object memory are valid after a refresh. However,
pointers to secondary-level memory (for example, string text pointers, collections, and
so on) may become invalid after a refresh.
For example, if the object is of type person with two attributes: salary (number), and
name (varchar2(20)). The type is:
struct Person {
OCINumber salary;
OCIString *name;
}

If the client has a pointer scott_p to Person instance, and calls OCIObjectRefresh() on
that instance, the pointer scott_p is still the same after the refresh, but the pointers to
second-level memory, such as scott_p->name, can be different.

See Also:
OCIObjectRefresh()

22.1.4 About Loading and Removing Object Copies
Pin, unpin, and free functions are discussed in this section.

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This section includes the following topics:
•

About Pinning an Object Copy

•

About Unpinning an Object Copy

•

About Freeing an Object Copy

22.1.4.1 About Pinning an Object Copy
When an application must dereference a REF in the object cache, it calls
OCIObjectPin(). This call dereferences the REF and pins the object copy in the cache.
As long as the object copy is pinned, it is guaranteed to be accessible by the
application. OCIObjectPin() takes a pin option, any, recent, or latest. The data type of
the pin option is OCIPinOpt.
•

If the any (OCI_PIN_ANY) option is specified, the object cache immediately returns
the object copy that is in the cache, if one exists. If no copy is in the cache, the
object cache loads the latest object copy from the database and then returns the
object copy. The any option is appropriate for read-only, informational, fact, or
meta objects, such as products, sales representatives, vendors, regions, parts, or
offices. These objects usually do not change often, and even if they change, the
change does not affect the application.
Note that the object cache looks for the object copy only within the logical partition
of the cache for the specified connection. If there is no copy in the partition, the
latest copy of the object is loaded from the server.

•

If the latest (OCI_PIN_LATEST) option is specified, the object cache loads into the
cache the latest object copy from the database. It returns that copy unless the
object copy is locked in the cache, in which case the marked object copy is
returned immediately. If the object is in the cache and not locked, the latest object
copy is loaded and overwrites the existing one. The latest option is appropriate for
operational objects, such as purchase orders, bugs, line items, bank accounts, or
stock quotes. These objects usually change often, and it is important that the
program access these objects at their latest possible state.

•

If the recent (OCI_PIN_RECENT) option is specified, there are two possibilities:
–

If in the same transaction the object copy has been previously pinned using
the latest or recent option, the recent option becomes equivalent to the any
option.

–

If the previous condition does not apply, the recent option becomes equivalent
to the latest option.

When the program pins an object, the program also specifies one of two possible
values for the pin duration: session or transaction. The data type of the duration is
OCIDuration.
•

If the pin duration is session (OCI_DURATION_SESSION), the object copy remains
pinned until the end of session (that is, end of connection) or until it is unpinned
explicitly by the program (by calling OCIObjectUnpin()).

•

If the pin duration is transaction (OCI_DURATION_TRANS), the object copy remains
pinned until the end of transaction or until it is unpinned explicitly.

When loading an object copy into the cache from the database, the cache effectively
executes the following statement:
SELECT VALUE(t) FROM t WHERE REF(t) = :r

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Object Cache and Memory Management

In this statement, t is the object table storing the object, r is the REF, and the fetched
value becomes the value of the object copy in the cache.
Because the object cache effectively executes a separate SELECT statement to load
each object copy into the cache, in a read-committed transaction, object copies are not
guaranteed to be read-consistent with each other.
In a serializable transaction, object copies pinned as recent or latest are readconsistent with each other because the SELECT statements to load these object copies
are executed based on the same database snapshot.
Read-committed and serialized transactions refer to different isolation levels that a
database can support. There are other isolation levels also, such as readuncommitted, repeatable read, and so on. Each isolation level permits more or less
interference among concurrent transactions. Typically, when an isolation level permits
more interference, simultaneous transactions have higher concurrency. In a readcommitted transaction, when a query is executed multiple times, this type of
transaction can produce inconsistent sets of data because it allows changes made by
other committed transactions to be seen. This does not happen in serializable
transactions.
The object cache model is orthogonal to or independent of the Oracle Database
transaction model. The behavior of the object cache does not change based on the
transaction model, even though the objects that are retrieved from the server through
the object cache can be different when running the same program under different
transaction models (for example, read-committed versus serializable).

Note:
For OCIObjectArrayPin() the pin option has no effect, because objects are
always retrieved from the database. If a REF is to an object in the cache,
OCIObjectArrayPin() fails with:
ORA-22881: dangling REF

See Also:
•

OCIObjectPin()

•

OCIObjectArrayPin()

22.1.4.2 About Unpinning an Object Copy
An object copy can be unpinned when it is no longer used by the program.
It then becomes available to be freed. An object copy must be both completely
unpinned and unmarked to become eligible to be implicitly freed by the cache when
the cache begins to run out of memory. To be completely unpinned, an object copy
that has been pinned n times must be unpinned n times.
An unpinned but marked object copy is not eligible for implicit freeing until the object
copy is flushed or explicitly unmarked by the user. However, the object cache implicitly

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frees object copies only when it begins to run out of memory, so an unpinned object
copy need not necessarily be freed. If it has not been implicitly freed and is pinned
again (with the any or recent options), the program gets the same object copy.
An application calls OCIObjectUnpin() or OCIObjectPinCountReset() to unpin an object
copy. In addition, a program can call OCICacheUnpin() to completely unpin all object
copies in the cache for a specific connection.

See Also:
•

OCIObjectUnpin()

•

OCIObjectPinCountReset()

•

OCICacheUnpin()

22.1.4.3 About Freeing an Object Copy
Freeing an object copy removes it from the object cache and frees up its memory.
The cache supports two methods for freeing up memory:
•

Explicit freeing – A program explicitly frees or removes an object copy from the
cache by calling OCIObjectFree(), which takes an option to (forcefully) free either a
marked or pinned object copy. The program can also call OCIObjectFree() to free
all object copies in the cache.

•

Implicit freeing – if the cache begins to run out of memory, it implicitly frees object
copies that are both unpinned and unmarked. Unpinned objects that are marked
are eligible for implicitly freeing only when the object copy is flushed or unmarked.

For memory management reasons, it is important that applications unpin objects when
they are no longer needed. This makes these objects available for aging out of the
cache, and makes it easier for the cache to free memory when necessary.
OCI does not provide a function to free unreferenced objects in the client-side cache.

See Also:
•

Object Cache Parameters for more information

•

OCIObjectFree()

22.1.5 About Making Changes to Object Copies
Functions for marking and unmarking object copies are discussed in this section.
This section includes the following topics:
•

About Marking an Object Copy

•

About Unmarking an Object Copy

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22.1.5.1 About Marking an Object Copy
An object copy can be created, updated, and deleted locally in the cache.
If the object copy is created in the cache (by calling OCIObjectNew()), the object copy is
marked for insert by the object cache, so that the object is inserted in the server when
the object copy is flushed.
If the object copy is updated in the cache, the user must notify the object cache by
marking the object copy for update (by calling OCIObjectMarkUpdate()). When the object
copy is flushed, the corresponding object in the server is updated with the value in the
object copy.
If the object copy is deleted, the object copy is marked for delete in the object cache
(by calling OCIObjectMarkDelete()). When the object copy is flushed, the corresponding
object in the server is deleted. The memory of the marked object copy is not freed until
it is flushed and unpinned. When pinning an object marked for delete, the program
receives an error, as if the program is dereferencing a dangling reference.
When a user makes multiple changes to an object copy, it is the final results of these
changes that are applied to the object in the server when the copy is flushed. For
example, if the user updates and deletes an object copy, the object in the server is
deleted when the object copy is flushed. Similarly, if an attribute of an object copy is
updated multiple times, it is the final value of this attribute that is updated in the server
when the object copy is flushed.
The program can mark an object copy as updated or deleted only if the object copy
has been loaded into the object cache.

See Also:
•

OCIObjectNew()

•

OCIObjectMarkUpdate()

•

OCIObjectMarkDelete()

22.1.5.2 About Unmarking an Object Copy
A marked object copy can be unmarked in the object cache.
By unmarking a marked object copy, the program ensures that the changes that are
made to the object copy are not flushed to the server. The object cache does not undo
the local changes that are made to the object copy.
A program calls OCIObjectUnmark() to unmark an object. In addition, a program can call
OCICacheUnmark() to unmark all object copies in the cache for a specific connection.

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See Also:
•

OCIObjectUnmark()

•

OCICacheUnmark()

22.1.6 About Synchronizing Object Copies with the Server
Cache and server synchronization operations (flushing, refreshing) are discussed in
this section.
This section includes the following topics:
•

About Flushing Changes to the Server

•

About Refreshing an Object Copy

22.1.6.1 About Flushing Changes to the Server
When the program flushes the object copy, it writes the local changes made to a
marked object copy in the cache to the server.
The program can call OCIObjectFlush() to flush a single object copy. The program can
call OCICacheFlush() to flush all marked object copies in the cache or a list of selected
marked object copies. OCICacheFlush() flushes objects associated with a specific
service context. See OCICacheFlush().
After the object copy is flushed, it is unmarked. (Note that the object is locked in the
server after it is flushed; the object copy is therefore marked as locked in the cache.)

Note:
The OCIObjectFlush() operation incurs only a single server round-trip even if
multiple objects are being flushed.

The callback function (an optional argument to the OCIObjectFlush() call) enables an
application to flush only dirty objects of a certain type. The application can define a
callback that returns only the desired objects. In this case, the operation still incurs
only a single server round-trip for the flush.
In the default mode during OCIObjectFlush(), the objects are flushed in the order that
they are marked dirty. The performance of this flush operation can be considerably
improved by setting the OCI_ATTR_CACHE_ARRAYFLUSH attribute in the environment handle.
However, the OCI_ATTR_CACHE_ARRAYFLUSH attribute should be used only if the order in
which the objects are flushed is not important. While this attribute is in effect, the dirty
objects are grouped together and sent to the server in a manner that enables the
server to efficiently update its tables. When this attribute is enabled, it is not
guaranteed that the order in which the objects are marked dirty is preserved.

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See Also:
•

Environment Handle Attributes

•

OCIObjectFlush()

•

OCICacheFlush()

22.1.6.2 About Refreshing an Object Copy
When refreshed, an object copy is reloaded with the latest value of the corresponding
object in the server.
The latest value may contain changes made by other committed transactions and
changes made directly (not through the object cache) in the server by the transaction.
The program can change objects directly in the server using SQL DML, triggers, or
stored procedures.
To refresh a marked object copy, the program must first unmark the object copy. An
unpinned object copy is freed when it is refreshed (that is, when the whole cache is
refreshed).
The program can call OCIObjectRefresh() to refresh a single object copy or
OCICacheRefresh() to refresh all object copies in the cache, all object copies that are
loaded in a transaction (that is, object copies that are pinned recent or pinned latest),
or a list of selected object copies.
When an object is flushed to the server, triggers can be fired to modify more objects in
the server. The same objects (modified by the triggers) in the object cache become
out-of-date, and must be refreshed before they can be locked or flushed.
The various meta-attribute flags and durations of an object are modified as described
in Table 22-1 after being refreshed.
Table 22-1

Object Attributes After a Refresh Operation

Object Attribute

Status After Refresh

Existent

Set to appropriate value

Pinned

Unchanged

Flushed

Reset

Allocation duration

Unchanged

Pin duration

Unchanged

During the refresh operation, the object cache loads the new data into the top-level
memory of an object copy, thus reusing the top-level memory. The top-level memory
of an object copy contains the inline attributes of the object. However, the memory for
the out-of-line attributes of an object copy can be freed and relocated, because the
out-of-line attributes can vary in size.

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See Also:
•

Memory Layout of an Instance for more information about object memory

•

OCIObjectRefresh()

•

OCICacheRefresh()

22.1.7 Object Locking
OCI functions related to object locking are discussed in this section.
This section includes the following topics:
•

Lock Options

•

About Locking Objects for Update

•

About Locking with the NOWAIT Option

•

About Implementing Optimistic Locking

22.1.7.1 Lock Options
When pinning an object, you can specify whether the object should be locked or not
through lock options.
When an object is locked, a server-side lock is acquired, which prevents any other
user from modifying the object. The lock is released when the transaction commits or
rolls back. The different lock options are as follows:
•

The lock option OCI_LOCK_NONE instructs the cache to pin the object without locking.

•

The lock option OCI_LOCK_X instructs the cache to pin the object only after acquiring
a lock. If the object is currently locked by another user, the pin call with this option
waits until it can acquire the lock before returning to the caller. This is equivalent to
executing a SELECT FOR UPDATE statement.

•

The lock option OCI_LOCK_X_NOWAIT instructs the cache to pin the object only after
acquiring a lock. Unlike the OCI_LOCK_X option, the pin call with the
OCI_LOCK_X_NOWAIT option does not wait if the object is currently locked by another
user. This is equivalent to executing a SELECT FOR UPDATE WITH NOWAIT statement.

22.1.7.2 About Locking Objects for Update
The program can optionally call OCIObjectLock() to lock an object for update.
This call instructs the object cache to get a row lock on the object in the database. This
is similar to executing the following statement:
SELECT NULL FROM t WHERE REF(t) = :r FOR UPDATE

In this statement, t is the object table storing the object to be locked, and r is the REF
identifying the object. The object copy is marked locked in the object cache after
OCIObjectLock() is called.

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To lock a graph or set of objects, several OCIObjectLock() calls are required (one for
each object) or the array pin OCIObjectArrayPin() call can be used for better
performance.
By locking an object, the application is guaranteed that the object in the cache is up-todate. No other transaction can modify the object while the application has it locked.
At the end of a transaction, all locks are released automatically by the server. The
locked indicator in the object copy is reset.

See Also:
•

OCIObjectLock()

•

OCIObjectArrayPin()

22.1.7.3 About Locking with the NOWAIT Option
Occasionally, an application attempts to lock an object that is currently locked by
another user. In this case, the application is blocked.
To avoid blocking when trying to lock an object, an application can use the
OCIObjectLockNoWait() call instead of OCIObjectLock(). This function returns an error if it

cannot lock an object immediately because it is locked by another user.
The NOWAIT option is also available to pin calls by passing a value of OCI_LOCK_X_NOWAIT
as the lock option parameter.

See Also:
•

OCIObjectLockNoWait()

•

OCIObjectLock()

22.1.7.4 About Implementing Optimistic Locking
There are two options available for implementing optimistic locking in an OCI
application.
Optimistic locking makes the assumption that a transaction will modify objects in the
cache, flush them, and commit the changes successfully.
Optimistic Locking Option 1
The first optimistic locking option is for OCI applications that run transactions at the
serializable level.
OCI supports calls that allow you to dereference and pin objects in the object cache
without locking them, modify them in the cache (again without locking them), and then
flush them (the dirtied objects) to the database.
During the flush operation, if a dirty object has been modified by another committed
transaction since the beginning of your transaction, a nonserializable transaction error

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is returned. If none of the dirty objects has been modified by any other transaction
since the beginning of your transaction, then your transaction writes the changes to
the database successfully.

Note:
OCITransCommit() flushes dirty objects into the database before committing a

transaction.
The preceding mechanism effectively implements an optimistic locking model.
Optimistic Locking Option 2
Alternately, an application can enable object change detection mode. To do this
operation, set the OCI_ATTR_OBJECT_DETECTCHANGE attribute of the environment handle to
a value of TRUE.
When this mode has been activated, the application receives an ORA-08179 error
("concurrency check failed") when it attempts to flush an object that has been
changed in the server by another committed transaction. The application can then
handle this error in an appropriate manner.

See Also:
OCITransCommit()

22.1.8 Commit and Rollback in Object Applications
When a transaction is committed (OCITransCommit()), all marked objects are flushed to
the server.
If an object copy is pinned with a transaction duration, the object copy is unpinned.
When a transaction is rolled back, all marked objects are unmarked. If an object copy
is pinned with a transaction duration, the object copy is unpinned.

See Also:
OCITransCommit()

22.1.9 Object Duration
To maintain free space in memory, the object cache attempts to reuse objects'
memory whenever possible. The object cache reuses an object's memory when the
object's lifetime (allocation duration) expires or when the object's pin duration expires.
The allocation duration is set when an object is created with OCIObjectNew(), and the
pin duration is set when an object is pinned with OCIObjectPin(). The data type of the
duration value is OCIDuration.

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Note:
The pin duration for an object cannot be longer than the object's allocation
duration.

When an object reaches the end of its allocation duration, it is automatically deleted
and its memory can be reused. The pin duration indicates when an object's memory
can be reused; memory is reused when the cache is full.
OCI supports two predefined durations:
•

Transaction (OCI_DURATION_TRANS)

•

Session (OCI_DURATION_SESSION)

The transaction duration expires when the containing transaction ends (commits or
terminates). The session duration expires when the containing session or connection
ends.
The application can explicitly unpin an object using OCIObjectUnpin(). To minimize
explicit unpinning of individual objects, the application can unpin all objects currently
pinned in the object cache using the function OCICacheUnpin(). By default, all objects
are unpinned at the end of the pin duration.
This section includes the following topic: Durations Example.

See Also:
•

OCIObjectNew()

•

OCIObjectPin()

•

OCIObjectUnpin()

•

OCICacheUnpin()

22.1.9.1 Durations Example
Illustrates the use of the different durations in an application.
Table 22-2 illustrates the use of the different durations in an application. Four objects
are created or pinned in this application over the course of one connection and three
transactions. The first column is the relative time indicator. The second column
indicates the action performed by the database, and the third column indicates the
function that performs the action. The remaining columns indicate the states of the
various objects at each point in the application.
For example, Object 1 comes into existence at T2 when it is created with a connection
duration, and it exists until T19 when the connection is terminated. Object 2 is pinned
at T7 with a transaction duration, after being fetched at T6, and it remains pinned until
T9 when the transaction is committed.

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Table 22-2

Example of Allocation and Pin Durations

Time

Application Action

Function

Object 1

Object 2

Object 3

Object 4

T1

Establish connection

-

-

-

-

-

T2

Create object 1 - allocation
duration = connection

OCIObjectNew()

Exists

-

-

-

T5

Start Transaction1

OCITransStart()

Exists

-

-

-

T6

SQL - fetch REF to object 2

-

Exists

-

-

-

T7

Pin object 2 - pin duration =
transaction

OCIObjectPin()

Exists

Pinned

-

-

T8

Process application data

-

Exists

Pinned

-

-

T9

Commit Transaction1

OCITransCommit()

Exists

Unpinned

-

-

T10

Start Transaction2

OCITransStart()

Exists

-

-

-

T11

Create object 3 - allocation
duration = transaction

OCIObjectNew()

Exists

-

Exists

-

T12

SQL - fetch REF to object 4

-

Exists

-

Exists

-

T13

Pin object 4 - pin duration =
connection

OCIObjectPin()

Exists

-

Exists

Pinned

T14

Commit Transaction2

OCITransCommit()

Exists

-

Deleted

Pinned

T15

Terminate session1

OCIDurationEnd()

Exists

-

-

Pinned

T16

Start Transaction3

OCITransStart()

Exists

-

-

Pinned

T17

Process application data

-

Exists

-

-

Pinned

T18

Commit Transaction3

OCITransCommit()

Exists

-

-

Pinned

T19

Terminate connection

-

Deleted

-

-

Unpinned

See Also:
•

The descriptions of OCIObjectNew() and OCIObjectPin() in OCI
Navigational and Type Functions for specific information about
parameter values that can be passed to these functions

•

About Creating Objects for information about freeing up an object's
memory before its allocation duration has expired

22.1.10 Memory Layout of an Instance
An instance in memory is composed of a top-level memory chunk of the instance, a
top-level memory of the null indicator structure and optionally, some secondary
memory chunks.
Consider the DEPARTMENT row type defined in Example 22-1.
The C representation of the DEPARTMENT is shown in Example 22-2.
Each instance of DEPARTMENT has a top-level memory chunk that contains the top-level
attributes such as dep_name, budget, manager, and employees. The attributes dep_name and

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Object Navigation

employees are pointers to the additional memory (the secondary memory chunks). The
secondary memory is used to contain the data for the embedded instances (for
example, employees varray and dep_name string).

The top-level memory of the null indicator structure contains the null statuses of the
attributes in the top-level memory chunk of the instance. In Example 22-2, the top-level
memory of the null structure contains the null statuses of the attributes dep_name,
budget, and manager, and the atomic nullity of employees.
Example 22-1

Object Type Representation of a Department Row

CREATE TYPE department AS OBJECT
( dep_name
varchar2(20),
budget
number,
manager
person,
/* person is an object type */
employees
person_array ); /* varray of person objects */

Example 22-2

C Representation of a Department Row

struct department
{
OCIString * dep_name;
OCINumber budget;
struct person manager;
OCIArray * employees;
);
typedef struct department department;

22.2 Object Navigation
This section discusses how OCI applications can navigate through graphs of objects in
the object cache.
This section includes the following topic: Simple Object Navigation.

22.2.1 Simple Object Navigation
If an application retrieves an object with an attribute that is a REF to another object, the
application can use OCI calls to traverse the object graph and access the referenced
instance.
In Example 22-1 and Example 22-2, the object retrieved by the application was a
simple object, whose attributes were all scalar values.
As an example, consider the following declaration for a new type in the database:
CREATE TYPE person_t AS OBJECT
( name
VARCHAR2(30),
mother
REF person_t,
father
REF person_t);

An object table of person_t objects is created with the following statement:
CREATE TABLE person_table OF person_t;

Instances of the person_t type can now be stored in the typed table. Each instance of
person_t includes references to two other objects, which would also be stored in the
table. A NULL reference could represent a parent about whom information is not
available.

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An object graph is a graphical representation of the REF links between object instances.
For example, Figure 22-2 depicts an object graph of person_t instances, showing the
links from one object to another. The circles represent objects, and the arrows
represent references to other objects. The M and F adjacent to the arrows indicate
mother and father, respectively.

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Object Navigation

Figure 22-2

Object Graph of person_t Instances

person1
M

F

person2

person3

M

F

M

F

NULL

person4

person6

person5

M

F

M

M

F

F

person1

M

F

person2

M

person3

F

M

F

NULL

person4

M

person6

person5

F

M

F

M

F

In this case, each object has links to two other instances (M and F) of the same object.
This need not always be the case. Objects may have links to other object types. Other

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OCI Navigational Functions

types of graphs are also possible. For example, if a set of objects is implemented as a
linked list, the object graph could be viewed as a simple chain, where each object
references either the previous or next objects or both in the linked list.
You can use the methods described earlier in this chapter to retrieve a reference to a
person_t instance and then pin that instance. OCI provides functionality that enables
you to traverse the object graph by following a reference from one object to another.
As an example, assume that an application fetches the person1 instance in the
preceding graph and pins it as pers_1. Once that has been done, the application can
access the mother instance of person1 and pin it into pers_2 through a second pin
operation:
OCIObjectPin(env, err, pers_1->mother, OCI_PIN_ANY, OCI_DURATION_TRANS,
OCI_LOCK_X, (OCIComplexObject *) 0, &pers_2);

In this case, an OCI fetch operation is not required to retrieve the second instance.
The application could then pin the father instance of person1, or it could operate on the
reference links of person2.

Note:
Attempting to pin a NULL or dangling REF results in an error on the
OCIObjectPin() call.

See Also:
OCIObjectPin()

22.3 OCI Navigational Functions
This section provides a brief summary of the available OCI navigational functions.
The functions are grouped according to their general functionality.
This section includes the following topics:
•

About Pin/Unpin/Free Functions

•

About Flush and Refresh Functions

•

About Mark and Unmark Functions

•

About Object Meta-Attribute Accessor Functions

•

About Other Functions

Earlier sections of this chapter describe the use of these functions.
The navigational functions follow a naming scheme that uses different prefixes for
different types of functionality:
OCICache*() – These functions are cache operations.

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OCI Navigational Functions

OCIObject*() – These functions are individual object operations.

See Also:
OCI Navigational and Type Functions for more detailed descriptions of each
of these functions

22.3.1 About Pin/Unpin/Free Functions
Lists and describes the pin, unpin, and free functions.
The functions in Table 22-3 are available to pin, unpin, or free objects.
Table 22-3

Pin, Free, and Unpin Functions

Function

Purpose

OCICacheFree()

Free all instances in the cache

OCICacheUnpin()

Unpin persistent objects in cache or connection

OCIObjectArrayPin()

Pin an array of references

OCIObjectFree()

Free and unpin a standalone instance

OCIObjectPin()

Pin an object

OCIObjectPinCountReset()

Unpin an object to zero pin count

OCIObjectPinTable()

Pin a table object with a given duration

OCIObjectUnpin()

Unpin an object

22.3.2 About Flush and Refresh Functions
Lists and describes the flush and refresh functions.
The functions in Table 22-4 are available to flush modified objects to the server.
Table 22-4

Flush and Refresh Functions

Function

Purpose

OCICacheFlush()

Flush modified persistent objects in cache to server

OCIObjectFlush()

Flush a modified persistent object to the server

OCICacheRefresh()

Refresh pinned persistent objects in the cache

OCIObjectRefresh()

Refresh a single persistent object

22.3.3 About Mark and Unmark Functions
Lists and describes the mark and unmark functions.
The functions in Table 22-5 allow an application to mark or unmark an object by
modifying one of its meta-attributes.

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Table 22-5

Mark and Unmark Functions

Function

Purpose

OCIObjectMarkDeleteByRef()

Mark an object deleted when given a REF

OCIObjectMarkUpdate()

Mark an object as updated (dirty)

OCIObjectMarkDelete()

Mark an object deleted or delete a value instance

OCICacheUnmark()

Unmark all objects in the cache

OCIObjectUnmark()

Mark a given object as updated

OCIObjectUnmarkByRef()

Mark an object as updated, when given a REF

22.3.4 About Object Meta-Attribute Accessor Functions
Lists and describes the meta-attribute accessor functions.
The functions in Table 22-6 allow an application to access the meta-attributes of an
object.
Table 22-6

Object Meta-Attributes Functions

Function

Purpose

OCIObjectExists()

Get existence status of an instance

OCIObjectGetInd()

Get null structure of an instance

OCIObjectIsDirty()

Has an object been marked as updated?

OCIObjectIsLocked()

Is an object locked?

22.3.5 About Other Functions
Lists and describes the miscellaneous functions.
The functions in Table 22-7 provide additional object functionality for OCI applications.
Table 22-7

Other Object Functions

Function

Purpose

OCIObjectCopy()

Copy one instance to another

OCIObjectGetObjectRef()

Return a reference to a given object

OCIObjectGetTypeRef()

Get a reference to a TDO of an instance

OCIObjectLock()

Lock a persistent object

OCIObjectLockNoWait()

Lock an object in NOWAIT mode

OCIObjectNew()

Create a new instance

22.4 Type Evolution and the Object Cache
When type information is requested based on the type name, OCI returns the type
descriptor object (TDO) corresponding to the latest version of the type.

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Because there is no synchronization between the server and the object cache, the
TDO in the object cache may not be current.
It is possible that the version of the image might differ from the TDO version during the
pinning of an object. Then, an error is issued. It is up to you to stop the application or
refresh the TDO and repin the object. Continuing with the application may cause the
application to fail because even if the image and the TDO are at the same version,
there is no guarantee that the object structure (that is, C struct) defined in the
application is compatible with the new type version, especially when an attribute has
been dropped from the type in the server.
Thus, when the structure of a type is altered, you must regenerate the header files of
the changed type, modify their application, recompile, and relink before executing the
program again.

See Also:
About Type Evolution

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23
OCI Support for XML
Oracle XML DB provides support for storing and manipulating XML instances by using
the XMLType data type. You can access these XML instances with OCI, in conjunction
with the C DOM API for XML.
An application program must initialize the usual OCI handles, such as the server
handle or the statement handle, and it must then initialize the XML context. The
program can either operate on XML instances in the back end or create new instances
on the client side. The initialized XML context can be used with all the C DOM
functions.
XML data stored in Oracle XML DB can be accessed on the client side with the C
DOM structure xmldocnode. You can use this structure for binding, defining, and
operating on XML values in OCI statements.
This section includes the following topics:
•

XML Context

•

XML Data on the Server

•

Using OCI XML DB Functions

•

OCI Client Access to Binary XML

See Also:
•

OCI XML DB Functions for information about the XML support in C

•

Oracle XML DB Developer’s Guide for more information about using the
C API for XML, including a binary XML example

•

Oracle XML Developer's Kit Programmer's Guidefor more information
about the XML parser for C

•

Oracle Database XML C API Reference for information about the DOM
C APIs for XML

23.1 XML Context
An XML context is a required parameter in all the C DOM API functions.
This opaque context encapsulates information pertaining to data encoding, error
message language, and so on. The contents of this context are different for XDK and
for Oracle XML DB applications.
For Oracle XML DB, there are two OCI functions provided to initialize and free an XML
context:

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xmlctx *OCIXmlDbInitXmlCtx (OCIEnv *envhp, OCISvcCtx *svchp, OCIError *errhp,
ocixmldbparam *params, ub4 num_params);
void OCIXmlDbFreeXmlCtx (xmlctx *xctx);

23.2 XML Data on the Server
XML data on the server can be operated on with OCI statement calls. You can bind
and define XMLType values using xmldocnode, as with other object instances.
OCI statements are used to select XML data from the server. This data can be used in
the C DOM functions directly. Similarly, the values can be bound back to SQL
statements directly.

23.3 Using OCI XML DB Functions
To initialize and terminate the XML context, use the functions OCIXmlDbInitXmlCtx()
and OCIXmlDbFreeXmlCtx() respectively.
The header file ocixmldb.h is used with the unified C API.
Example 23-1 is a code fragment of a tested example that shows how to perform
operations with the C API.
Example 23-1

Initializing and Terminating XML Context with a C API

#ifndef S_ORACLE
#include 
#endif
#ifndef ORATYPES_ORACLE
#include 
#endif
#ifndef XML_ORACLE
#include 
#endif
#ifndef OCIXML_ORACLE
#include 
#endif
#ifndef OCI_ORACLE
#include 
#endif
#include 
typedef struct test_ctx {
OCIEnv *envhp;
OCIError *errhp;
OCISvcCtx *svchp;
OCIStmt *stmthp;
OCIServer *srvhp;
OCIDuration dur;
OCISession *sesshp;
oratext *username;
oratext *password;
} test_ctx;
...
void main()
{
test_ctx temp_ctx;

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OCI Client Access to Binary XML

test_ctx *ctx = &temp_ctx;
OCIType *xmltdo = (OCIType *) 0;
xmldocnode *doc = (xmldocnode *)0;
ocixmldbparam params[1];
xmlnode *quux, *foo, *foo_data, *top;
xmlerr err;
sword status = 0;
xmlctx *xctx;
...
/* Initialize envhp, svchp, errhp, dur, stmthp */
...
/* Get an xml context */
params[0].name_ocixmldbparam = XCTXINIT_OCIDUR;
params[0].value_ocixmldbparam = &ctx->dur;
xctx = OCIXmlDbInitXmlCtx(ctx->envhp, ctx->svchp, ctx->errhp, params, 1);
/* Do unified C API operations next */
...
/* Free the statement handle using OCIHandleFree() */
...
/* Free the allocations associated with the context */
OCIXmlDbFreeXmlCtx(xctx);
/* Free envhp, svchp, errhp, stmthp */
...
}

See Also:
•

OCIXmlDbInitXmlCtx()

•

OCIXmlDbFreeXmlCtx()

23.4 OCI Client Access to Binary XML
The middle tier and client tiers can produce, consume, and process XML in binary
XML format.
The C application fetches data from the XML DB repository, performs updates on the
XML using DOM, and stores it back in the database. Or an XML document is created
or input on the client and XSLT, XQuery, and other utilities can be used on it. Then the
output XML is saved in XML DB.
A client application requires a connection (called a metadata connection) to the
metadata repository (typically a back-end database) to fetch token definitions, XML
schemas, and DTDs while encoding or decoding a binary XML document.
A repository context is initialized using either a dedicated connection or a connection
pool. The connection obtained from the repository context is used to fetch metadata
such as token definitions and XML schemas. In contrast, the application also has data
connections that are used for the regular transfer of data (including XML data) to and
from the database. A repository context is explicitly associated with (one or more) data
connections. When XML data is read or written from or to the database using the data
connection, the appropriate repository context is accessed during the underlying

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OCI Client Access to Binary XML

encode or decode operations. As required, the metadata connection is used to fetch
the metadata from the repository.
This section includes the following topics:
•

Accessing XML Data from an OCI Application

•

Repository Context

•

Create Repository Context from a Dedicated OCI Connection

•

Create Repository Context from a Connection Pool

•

About Associating Repository Context with a Data Connection

•

About Setting XMLType Encoding Format Preference

•

Example of Using a Connection Pool

23.4.1 Accessing XML Data from an OCI Application
Your C application can use OCI to access persistent XML in the database and the
Unified XML C API to operate on the fetched XML data.
The following steps are taken by a client application:
1.

Create the usual OCI handles such as OCIEnv, OCISvcCtx, and OCIError.

2.

Create one or more repository contexts to fetch the binary XML metadata.

3.

Associate the repository context with the data connection.

4.

Bind or define (xmldocnode) variables into the select, insert, and update statements.

5.

Execute the select, insert, or update statement to fetch or store the XML
document. At this point, the client OCI libraries interact with the database back end
to fetch the needed XML Schemas, DTDs, token definitions, and so on.

6.

Use the Unified C API to operate on the XML data (DOM).

23.4.2 Repository Context
OCIBinXmlReposCtx is the repository context data structure.

The client application creates this context by providing the connection information to
the metadata repository. An application can create multiple repository contexts to
connect to multiple token repositories. A repository context is explicitly associated with
a data connection (OCISvcCtx). When the system must fetch metadata to encode or
decode data to or from a data connection, it accesses the appropriate metadata.
It is recommended that applications create one repository context per OCIEnv. This
allows better concurrency for multithreaded applications.
The repository context can be created out of a dedicated OCI connection or an OCI
connection pool.

23.4.3 Create Repository Context from a Dedicated OCI Connection
OCIBinXmlCreateReposCtxFromConn() creates a repository context using the specified

dedicated OCI connection.

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The OCI connection is only to be used for metadata access and should not be used in
any other scenarios by the application. Also note that the access to this connection is
serialized; that is, if multiple threads try to use the same connection, access is limited
to one thread at a time. For scalability reasons, it is recommended that applications
create a repository context using a connection pool, as described in the next section.
Note: You can also potentially pass in the same connection as the one being used for
data. However, this might result in an error in certain cases where the client system
attempts to contact the metadata repository while part of another operation (such as
select or insert).

See Also:
OCIBinXmlCreateReposCtxFromConn()

23.4.4 Create Repository Context from a Connection Pool
OCIBinXmlCreateReposCtxFromCPool() creates a repository context from a connection

pool.
When the application accesses the back-end repository, any available connection from
the pool is used. Further, this connection is released back to the pool as soon as the
metadata operation is complete. Connection pools are highly recommended for
multithreaded application scenarios. Different threads can use different connections in
the pool and release them as soon as they are done. This approach allows for higher
scalability and concurrency with a smaller number of physical connections.

See Also:
OCIBinXmlCreateReposCtxFromCPool()

23.4.5 About Associating Repository Context with a Data Connection
OCIBinXmlSetReposCtxForConn() associates a repository context with a data connection

described by OCISvcCtx *.
Multiple data connections can share the same repository context, but access to the
repository can be serialized (if it is based on a dedicated connection). When the
system must fetch the metadata for encode or decode operations, it looks up the
appropriate repository connection from the OCIEnv, OCISvcCtx pair and uses it to fetch
the metadata required.

See Also:
OCIBinXmlSetReposCtxForConn()

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OCI Client Access to Binary XML

23.4.6 About Setting XMLType Encoding Format Preference
By default, XML data sent to the database is encoded in one of these possible formats
(text, object-relational, or binary XML) based on certain internal criteria such as the
source format (if it was read from the DB). OCIBinXmlSetFormatPref() provides an
explicit mechanism to set the preference for encoding format. In the future, the default
format can be binary XML, but this function could be used to override it if needed.

See Also:
OCIBinXmlSetFormatPref()

23.4.7 Example of Using a Connection Pool
Creating a repository context from a connection pool and associating the repository
context with a data connection is shown in this example in the XML DB
documentation.
The database is local and the test is in single-threaded mode.

See Also:
Oracle XML DB Developer’s Guide for more information about using OCI and
the C API for XML with Oracle XML DB

23-6

24
Using the Object Type Translator with OCI
This chapter discusses the Object Type Translator (OTT), which is used to map
database object types and named collection types to C structs for use in OCI
applications.
This chapter contains these topics:
•

What Is the Object Type Translator?

•

OTT Command Line

•

Intype File

•

OTT Data Type Mappings

•

Outtype File

•

About Using OTT with OCI Applications

•

OTT Reference

24.1 What Is the Object Type Translator?
The Object Type Translator (OTT) assists in the development of C language
applications that make use of user-defined types in an Oracle database.
With SQL CREATE TYPE statements, you can create object types. The definitions of
these types are stored in the database, and can be used in the creation of database
tables. Once these tables are populated, an OCI programmer can access objects
stored in the tables.
An application that accesses object data must be able to represent the data in a host
language format. This is accomplished by representing object types as C structs.
Although it is possible for a programmer to code struct declarations by hand to
represent database object types, this can be very time-consuming and error-prone if
many types are involved. OTT obviates the need for such manual coding by
automatically generating appropriate struct declarations. In OCI, the application also
must call an initialization function generated by OTT.
In addition to creating structs that represent stored data types, OTT generates parallel
indicator structs that indicate whether an object type or its fields are NULL.
The Object Type Translator (OTT) converts database definitions of object types and
named collection types into C struct declarations that can be included in an OCI
application.
You must explicitly invoke OTT to translate database types to C representations.
On most operating systems, OTT is invoked on the command line. It takes as input an
intype file, and it generates an outtype file and one or more C header files and an
optional implementation file. The following is an example of a command that invokes
OTT:

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What Is the Object Type Translator?

ott userid=scott intype=demoin.typ outtype=demoout.typ code=c hfile=demo.h\
initfile=demov.c

This command causes OTT to connect to the database with user name scott. The
user is prompted for the password.
The implementation file (demov.c) contains the function to initialize the type version
table with information about the user-defined types translated.
Later sections of this chapter describe each of these parameters in more detail.
Sample demoin.typ file:
CASE=LOWER
TYPE emptype

Sample demoout.typ file:
CASE = LOWER
TYPE SCOTT.EMPTYPE AS emptype
VERSION = "$8.0"
HFILE = demo.h

In this example, the demoin.typ file contains the type to be translated, preceded by TYPE
(for example, TYPE emptype). The structure of the outtype file is similar to the intype file,
with the addition of information obtained by OTT.
Once OTT has completed the translation, the header file contains a C struct
representation of each type specified in the intype file, and a NULL indicator struct
corresponding to each type. Suppose for example, that the employee type listed in the
intype file was defined as shown in Example 24-1.
Then the header file generated by OTT (demo.h) includes, among other items, the
declarations shown in Example 24-2.
Example 24-3 shows what a sample implementation file (demov.c) produced by this
command contains.
Parameters in the intype file control the way generated structs are named. In this
example, the struct name emptype matches the database type name emptype. The
struct name is in lowercase because of the line CASE=lower in the intype file.
The data types that appear in the struct declarations (for example, OCIString, OCIInd)
are special data types.
The remaining sections of this chapter discuss the use of OTT with OCI, followed by a
reference section that describes command-line syntax, parameters, intype file
structure, nested #include file generation, schema names usage, default name
mapping, and restrictions.
Example 24-1

Definition of the Employee Object Type Listed in the Intype File

CREATE TYPE emptype AS OBJECT
(
name
VARCHAR2(30),
empno
NUMBER,
deptno
NUMBER,
hiredate DATE,
salary
NUMBER
);

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Example 24-2

Contents of the Generated Header File demo.h

struct emptype
{
OCIString * name;
OCINumber empno;
OCINumber deptno;
OCIDate hiredate;
OCINumber salary;
};
typedef struct emptype emptype;
struct emptype_ind
{
OCIInd _atomic;
OCIInd name;
OCIInd empno;
OCIInd deptno;
OCIInd hiredate;
OCIInd salary;
};
typedef struct employee_ind employee_ind;

Example 24-3

Contents of the demov.c File

#ifndef OCI_ORACLE
#include 
#endif
sword demov(OCIEnv *env, OCIError *err)
{
sword status = OCITypeVTInit(env, err);
if (status == OCI_SUCCESS)
status = OCITypeVTInsert(env, err,
"HR", 2,
"EMPTYPE", 7,
"$8.0", 4);
return status;
}

This section includes the following topics:
•

About Creating Types in the Database

•

About Invoking OTT

See Also:
OTT Data Type Mappings for more information about these types

24.1.1 About Creating Types in the Database
The first step in using OTT is to create object types or named collection types and
store them in the database.
This is accomplished through the use of the SQL CREATE TYPE statement.

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See Also:
Oracle Database SQL Language Reference for information about the CREATE
TYPE statement

24.1.2 About Invoking OTT
The next step is to invoke OTT. OTT parameters can be specified on the command
line, or in a file called a configuration file.
Certain parameters can also be specified in the intype file.
If a parameter is specified in more than one place, its value on the command line takes
precedence over its value in the intype file, which takes precedence over its value in a
user-defined configuration file, which takes precedence over its value in the default
configuration file.
For global options — that is, options on the command line or options at the beginning
of the intype file before any TYPE statements — the value on the command line
overrides the value in the intype file. (The options that can be specified globally in the
intype file are CASE, CODE, INITFILE, and INITFUNC, but not HFILE.) However, anything in
the intype file in a TYPE specification applies to a particular type only, and overrides
anything on the command line that would otherwise apply to the type. So if you enter
TYPE person HFILE=p.h, it applies to person only and overrides the HFILE on the
command line. The statement is not considered a command-line parameter.
This section includes the following topics:
•

Command Line

•

Configuration File

•

INTYPE File

24.1.2.1 Command Line
Parameters (also called options) set on the command line override any set elsewhere.

See Also:
OTT Command Line

24.1.2.2 Configuration File
A configuration file is a text file that contains OTT parameters.
Each nonblank line in the file contains one parameter, with its associated value or
values. If more than one parameter is put on a line, only the first one is used.
Whitespace is not allowed on any nonblank line of a configuration file.
A configuration file can be named on the command line. In addition, a default
configuration file is always read. This default configuration file must always exist, but

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OTT Command Line

can be empty. The name of the default configuration file is ottcfg.cfg, and the location
of the file is system-specific. For example, on Solaris, the file specification
is $ORACLE_HOME/precomp/admin/ottcfg.cfg. See your operating system-specific
documentation for further information.

24.1.2.3 INTYPE File
The intype file gives a list of user-defined types for OTT to translate.
The parameters CASE, HFILE, INITFUNC, and INITFILE can appear in the intype file.

See Also:
Intype File

24.2 OTT Command Line
On most operating systems, OTT is invoked on the command line.
You can specify the input and output files, and the database connection information,
among other things. Consult your operating system-specific documentation to see how
to invoke OTT.
This section includes the following topic: OTT Command-Line Invocation Example.

See Also:
About Using the Object Type Translator for Windows

24.2.1 OTT Command-Line Invocation Example
Shows how to invoke OTT from the command line.
Example 24-4 shows how to invoke OTT from the command line.

Note:
No spaces are permitted around the equal sign (=).

Example 24-4

Invoking OTT from the Command Line

ott userid=bren intype=demoin.typ outtype=demoout.typ code=c \
hfile=demo.h initfile=demov.c

The following sections describe the elements of the command line used in this
example.
This section includes the following topics:

24-5

Chapter 24

OTT Command Line

•

OTT

•

USERID

•

INTYPE

•

OUTTYPE

•

CODE

•

HFILE

•

INITFILE

See Also:
OTT Reference for a detailed discussion of the various OTT command-line
options

24.2.1.1 OTT
Causes OTT to be invoked.
It must be the first item on the command line.

24.2.1.2 USERID
Specifies the database connection information that OTT uses.
In Example 24-4, OTT attempts to connect with user name bren and is then prompted
for the password.

24.2.1.3 INTYPE
Specifies the name of the intype file that is used.
In Example 24-4, the name of the intype file is specified as demoin.typ.

24.2.1.4 OUTTYPE
Specifies the name of the outtype file.
When OTT generates the C header file, it also writes information about the translated
types into the outtype file. This file contains an entry for each of the types that is
translated, including its version string, and the header file to which its C representation
was written.
In Example 24-4, the name of the outtype file is specified as demoout.typ.

Note:
If the file specified by the outtype keyword exists, it is overwritten when OTT
runs. If the name of the outtype file is the same as the name of the intype file,
the outtype information overwrites the intype file.

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24.2.1.5 CODE
Specifies the target language for the translation.
The following options are available:
•

C (equivalent to ANSI_C)

•

ANSI_C (for ANSI C)

•

KR_C (for Kernighan & Ritchie C)

There is currently no default option, so this parameter is required.
Struct declarations are identical in both C dialects. The style in the initialization
function defined in the INITFILE file depends on whether KR_C is used. If the INITFILE
option is not used, all three options are equivalent.

24.2.1.6 HFILE
Specifies the name of the C header file to which the generated structs should be
written.
In Example 24-4, the generated structs are stored in a file called demo.h.

Note:
If the file specified by the hfile keyword exists, it is overwritten when OTT
runs, with one exception: if the contents of the file as generated by OTT are
identical to the previous contents of the file, OTT does not actually write to
the file. This preserves the modification time of the file so that Linux and
UNIX make and similar facilities on other operating systems do not perform
unnecessary recompilations.

24.2.1.7 INITFILE
Specifies the name of the C source file into which the type initialization function is to
be written.

Note:
If the file specified by the initfile keyword exists, it is overwritten when OTT
runs, with one exception: if the contents of the file as generated by OTT are
identical to the previous contents of the file, OTT does not actually write to
the file. This preserves the modification time of the file so that Linux and
UNIX make and similar facilities on other operating systems do not perform
unnecessary recompilations.

24-7

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Intype File

24.3 Intype File
When OTT runs, the intype file tells OTT which database types should be translated.
It can also control the naming of the generated structs. The intype file can be a usercreated file, or it can be the outtype file of a previous invocation of OTT. If the intype
parameter is not used, all types in the schema to which OTT connects are translated.
Example 24-5 shows a simple user-created intype file.
Example 24-5 is further described as follows.
The first line, with the CASE keyword, indicates that generated C identifiers should be in
lowercase. However, this CASE option is only applied to those identifiers that are not
explicitly mentioned in the intype file. Thus, employee and ADDRESS would always result
in C structures employee and ADDRESS, respectively. The members of these structures
would be named in lowercase.
In the lines that begin with the TYPE keyword specify which types in the database
should be translated: in this case, the employee, ADDRESS, item, Person, and
PURCHASE_ORDER types.
The TRANSLATE ... AS keywords specify that the name of an object attribute should be
changed when the type is translated into a C struct. In this case, the SALARY$ attribute
of the employee type is translated to salary.
The AS keyword in the final line specifies that the name of an object type should be
changed when it is translated into a struct. In this case, the PURCHASE_ORDER database
type is translated into a struct called p_o.
If AS is not used to translate a type or attribute name, the database name of the type or
attribute is used as the C identifier name, except that the CASE option is observed, and
any character that cannot be mapped to a legal C identifier character is replaced by an
underscore. Reasons for translating a type or attribute name include the following:
•

The name contains characters other than letters, digits, and underscores

•

The name conflicts with a C keyword.

•

The type name conflicts with another identifier in the same scope. This can
happen, for example, if the program uses two types with the same name from
different schemas.

•

The programmer prefers a different name.

OTT may need to translate additional types that are not listed in the intype file. This is
because OTT analyzes the types in the intype file for type dependencies before
performing the translation, and translates other types as necessary. For example, if
the ADDRESS type were not listed in the intype file, but the "Person" type had an attribute
of type ADDRESS, OTT would still translate ADDRESS because it is required to define the
"Person" type.
If you specify FALSE as the value of the TRANSITIVE parameter, then OTT does not
generate types that are not specified in the intype file.
A normal case-insensitive SQL identifier can be spelled in any combination of
uppercase and lowercase in the intype file, and is not enclosed within quotation marks.

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OTT Data Type Mappings

Use quotation marks, such as TYPE "Person", to reference SQL identifiers that have
been created in a case-sensitive manner (for example, CREATE TYPE "Person"). A SQL
identifier is case-sensitive if it was enclosed within quotation marks when it was
declared. Quotation marks can also be used to refer to a SQL identifier that is an OTTreserved word (for example, TYPE "CASE"). Therefore, when a name is enclosed within
quotation marks, the name enclosed within quotation marks must be in uppercase if
the SQL identifier was created in a case-insensitive manner (for example, CREATE TYPE
Case). If an OTT-reserved word is used to refer to the name of a SQL identifier but is
not enclosed within quotation marks, OTT reports a syntax error in the intype file.
Example 24-5

Contents of a User-Created Intype File

CASE=LOWER
TYPE employee
TRANSLATE SALARY$ AS salary
DEPTNO AS department
TYPE ADDRESS
TYPE item
TYPE "Person"
TYPE PURCHASE_ORDER AS p_o

See Also:
•

CASE

•

Structure of the Intype File for a more detailed specification of the
structure of the intype file and the available options

24.4 OTT Data Type Mappings
When OTT generates a C struct from a database type, the struct contains one element
corresponding to each attribute of the object type.
The data types of the attributes are mapped to types that are used in Oracle's object
data types. The data types found in Oracle Database include a set of predefined,
primitive types. These data types provide for the creation of user-defined types, such
as object types and collections.
Oracle Database also includes a set of predefined types that are used to represent
object type attributes in C structs. As an example, consider the object type definition in
Example 24-6, and its corresponding OTT-generated struct declarations in
Example 24-7.
The OTT output, assuming CASE=LOWER and no explicit mappings of type or attribute
names, is shown in Example 24-7.
The data types in the struct declarations—OCIString, OCINumber, OCIDate, and OCIInd—
are used here to map the data types of the object type attributes. The NUMBER data type
of the empno attribute maps to the OCINumber data type, for example. These data types
can also be used as the types of bind and define variables.

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OTT Data Type Mappings

Example 24-6

Object Type Definition for Employee

CREATE TYPE employee AS OBJECT
( name
VARCHAR2(30),
empno
NUMBER,
deptno
NUMBER,
hiredate DATE,
salary$
NUMBER);

Example 24-7

OTT-Generated Struct Declarations

struct employee
{ OCIString * name;
OCINumber empno;
OCINumber deptno;
OCIDate hiredate;
OCINumber salary_;
};
typedef struct emp_type emp_type;
struct employee_ind
{
OCIInd _atomic;
OCIInd name;
OCIInd empno;
OCIInd deptno;
OCIInd hiredate;
OCIInd salary_;
}
typedef struct employee_ind employee_ind;

This section includes the following topics:
•

About Mapping Object Data Types to C

•

OTT Type Mapping Example

•

Null Indicator Structs

•

OTT Support for Type Inheritance

See Also:
Null Indicator Structs for an explanation of the indicator struct (struct
employee_ind)

24.4.1 About Mapping Object Data Types to C
This section describes the mappings of Oracle object attribute types to C types
generated by OTT.
The previous section OTT Type Mapping Example includes examples of many of
these different mappings. Table 24-1 lists the mappings from types that you can use
as attributes to object data types that are generated by OTT and the corresponding
OCI type code values.

24-10

Chapter 24

OTT Data Type Mappings

Table 24-1

Object Data Type Mappings for Object Type Attributes

Object Attribute Types

C Mapping

OCITypeCode Values

BFILE

OCIBFileLocator*

OCI_TYPECODE_BFILE

BLOB

OCILobLocator * or
OCIBlobLocator *

OCI_TYPECODE_BLOB

CHAR(N), CHARACTER(N),
NCHAR(N)

OCIString *

OCI_TYPECODE_CHAR (n),
OCI_TYPECODE_NCHAR

CLOB, NCLOB

OCILobLocator * or
OCIClobLocator *

OCI_TYPECODE_CLOB,
OCI_TYPECODE_NCLOB

DATE

OCIDate

OCI_TYPECODE_DATE

ANSI DATE

OCIDateTime *

OCI_TYPECODE_TIMESTAMP

TIMESTAMP, TIMESTAMP WITH TIME OCIDateTime *
ZONE, TIMESTAMP WITH LOCAL
TIME ZONE

OCI_TYPECODE_TIMESTAMP,
OCI_TYPECODE_TIMESTAMP_TZ,
OCI_TYPECODE_TIMESTAMP_LTZ

INTERVAL YEAR TO MONTH,
INTERVAL DAY TO SECOND

OCIInterval *

OCI_TYPECODE_INTERVAL_YM,
OCI_TYPECODE_INTERVAL_DS

DEC, DEC(N), DEC(N,N)

OCINumber

OCI_TYPECODE_DECIMAL (p)

DECIMAL, DECIMAL(N),
DECIMAL(N,N)

OCINumber

OCI_TYPECODE_DECIMAL (p)

FLOAT, FLOAT(N), DOUBLE
PRECISION

OCINumber

OCI_TYPECODE_FLOAT (b)

BINARY_FLOAT

float

OCI_TYPECODE_BFLOAT

BINARY_DOUBLE

double

OCI_TYPECODE_BDOUBLE

INT, INTEGER, SMALLINT

OCINumber

OCI_TYPECODE_INTEGER,
OCI_TYPECODE_SMALLINT

Nested Object Type

C name of the nested
object type

OCI_TYPECODE_OBJECT

Nested Table

OCITable *

OCI_TYPECODE_TABLE

NUMBER, NUMBER(N),
NUMBER(N,N)

OCINumber

OCI_TYPECODE_NUMBER (p, s)

NUMERIC, NUMERIC(N),
NUMERIC(N,N)

OCINumber

OCI_TYPECODE_NUMBER (p, s)

RAW(N)

OCIRaw *

OCI_TYPECODE_RAW

REAL

OCINumber

OCI_TYPECODE_REAL

REF

OCIRef *

OCI_TYPECODE_REF

VARCHAR(N)

OCIString *

OCI_TYPECODE_VARCHAR (n)

VARCHAR2(N), NVARCHAR2(N)

OCIString *

OCI_TYPECODE_VARCHAR2 (n),
OCI_TYPECODE_NVARCHAR2

VARRAY

OCIArray *

OCI_TYPECODE_VARRAY

collections

OCIColl *

OCI_TYPECODE_NAMEDCOLLECTION

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Note:
For REF, varray, and nested table types, OTT generates a typedef. The type
declared in the typedef is then used as the type of the data member in the
struct declaration. For an example, see OTT Type Mapping Example.

If an object type includes an attribute of a REF or collection type, a typedef for the REF or
collection type is first generated. Then the struct declaration corresponding to the
object type is generated. The struct includes an element whose type is a pointer to the
REF or collection type.
If an object type includes an attribute whose type is another object type, OTT first
generates the nested type (if TRANSITIVE=TRUE). It then maps the object type attribute to
a nested struct of the type of the nested object type.
The Oracle C data types to which OTT maps non-object database attribute types are
structures, which, except for OCIDate, are opaque.

24.4.2 OTT Type Mapping Example
Shows the various type mappings created by OTT when given the database types.
Example 24-9 demonstrates the various type mappings created by OTT when given
the database types shown in Example 24-8.
The intype file includes the following:
CASE = LOWER
TYPE many_types

OTT generates the C structs shown in Example 24-9.

Note:
Comments are provided in Example 24-9 to help explain the structs. These
comments are not part of actual OTT output.

Notice that although only one item was listed for translation in the intype file, two
object types and two named collection types were translated. This is because the OTT
parameter TRANSITIVE has the default value of TRUE. As described in that section, when
TRANSITIVE=TRUE, OTT automatically translates any types that are used as attributes of
a type being translated, to complete the translation of the listed type.
This is not the case for types that are only accessed by a pointer or REF in an object
type attribute. For example, although the many_types type contains the attribute
another_ref REF other_type, a declaration of struct other_type was not generated.
This example also illustrates how typedefs are used to declare varray, nested table,
and REF types.
The typedefs occur near the beginning:

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typedef
typedef
typedef
typedef
typedef

OCIRef many_types_ref;
OCIRef object_type_ref;
OCIArray my_varray;
OCITable my_table;
OCIRef other_type_ref;

In the struct many_types, the varray, nested table, and REF attributes are declared:
struct many_types
{ ...
other_type_ref *
many_types_ref *
my_varray *
my_table *
...
}

Example 24-8

another_ref;
the_ref;
the_varray;
the_table;

Object Type Definitions for the OTT Type Mapping Example

CREATE TYPE my_varray AS VARRAY(5) of integer;
CREATE TYPE object_type AS OBJECT
(object_name
VARCHAR2(20));
CREATE TYPE my_table AS TABLE OF object_type;
CREATE TYPE other_type AS OBJECT (object_number NUMBER);
CREATE TYPE many_types AS OBJECT
( the_varchar
VARCHAR2(30),
the_char
CHAR(3),
the_blob
BLOB,
the_clob
CLOB,
the_object
object_type,
another_ref
REF other_type,
the_ref
REF many_types,
the_varray
my_varray,
the_table
my_table,
the_date
DATE,
the_num
NUMBER,
the_raw
RAW(255));

Example 24-9
Definitions

Various Type Mappings Created by OTT from Object Type

#ifndef MYFILENAME_ORACLE
#define MYFILENAME_ORACLE
#ifndef OCI_ORACLE
#include 
#endif
typedef OCIRef many_types_ref;
typedef OCIRef object_type_ref;
typedef OCIArray my_varray;
typedef OCITable my_table;
typedef OCIRef other_type_ref;
struct object_type
{
OCIString * object_name;
};

/* used in many_types */
/* used in many_types*/
/* used in many_types */

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typedef struct object_type object_type;
struct object_type_ind
/*indicator struct for*/
{
/*object_types*/
OCIInd _atomic;
OCIInd object_name;
};
typedef struct object_type_ind object_type_ind;
struct many_types
{
OCIString *
the_varchar;
OCIString *
the_char;
OCIBlobLocator * the_blob;
OCIClobLocator * the_clob;
struct object_type the_object;
other_type_ref * another_ref;
many_types_ref * the_ref;
my_varray *
the_varray;
my_table *
the_table;
OCIDate
the_date;
OCINumber
the_num;
OCIRaw *
the_raw;
};
typedef struct many_types many_types;
struct many_types_ind
/*indicator struct for*/
{
/*many_types*/
OCIInd _atomic;
OCIInd the_varchar;
OCIInd the_char;
OCIInd the_blob;
OCIInd the_clob;
struct object_type_ind the_object;
/*nested*/
OCIInd another_ref;
OCIInd the_ref;
OCIInd the_varray;
OCIInd the_table;
OCIInd the_date;
OCIInd the_num;
OCIInd the_raw;
};
typedef struct many_types_ind many_types_ind;
#endif

See Also:
TRANSITIVE

24.4.3 Null Indicator Structs
Each time OTT generates a C struct to represent a database object type, it also
generates a corresponding NULL indicator struct.
When an object type is selected into a C struct, NULL indicator information may be
selected into a parallel struct.

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For example, the following NULL indicator struct was generated in Example 24-9.
struct many_types_ind
{
OCIInd _atomic;
OCIInd the_varchar;
OCIInd the_char;
OCIInd the_blob;
OCIInd the_clob;
struct object_type_ind the_object;
OCIInd another_ref;
OCIInd the_ref;
OCIInd the_varray;
OCIInd the_table;
OCIInd the_date;
OCIInd the_num;
OCIInd the_raw;
};
typedef struct many_types_ind many_types_ind;

The layout of the NULL struct is important. The first element in the struct (_atomic) is the
atomic null indicator. This value indicates the NULL status for the object type as a
whole. The atomic null indicator is followed by an indicator element corresponding to
each element in the OTT-generated struct representing the object type.
Notice that when an object type contains another object type as part of its definition (in
the preceding example it is the object_type attribute), the indicator entry for that
attribute is the NULL indicator struct (object_type_ind) corresponding to the nested
object type (if TRANSITIVE=TRUE).
The varrays and nested tables contain the NULL information for their elements.
The data type for all other elements of a NULL indicator struct is OCIInd.

See Also:
NULL Indicator Structure for more information about atomic nullity

24.4.4 OTT Support for Type Inheritance
To support type inheritance of objects, OTT generates a C struct to represent an
object subtype by declaring the inherited attributes in an encapsulated struct with the
special name "_super", before declaring the new attributes.
Thus, for an object subtype that inherits from a supertype, the first element in the
struct is named "_super", followed by elements corresponding to each attribute of the
subtype. The type of the element named "_super" is the name of the supertype.
For example, suppose that you have a type Person_t, with subtype Student_t and
subtype Employee_t, as shown in Example 24-10.
Suppose that you also have an intype file with the content shown in Example 24-11.
Then, OTT generates the C structs for Person_t, Student_t, and Employee_t, and their
NULL indicator structs, as shown in Example 24-12.

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The preceding C mapping convention allows simple upcasting from an instance of a
subtype to an instance of a supertype in C to work properly. For example:
STUDENT_T *stu_ptr = some_ptr;
PERSON_T *pers_ptr = (PERSON_T *)stu_ptr;

/* some STUDENT_T instance */
/* upcasting */

The NULL indicator structs are generated similarly. Note that for the supertype Person_t
NULL indicator struct, the first element is "_atomic", and that for the subtypes Employee_t
and Student_t NULL indicator structs, the first element is "_super" (no atomic element is
generated for subtypes).
Example 24-10

Object Type and Subtype Definitions

CREATE TYPE Person_t AS OBJECT
( ssn
NUMBER,
name
VARCHAR2(30),
address VARCHAR2(100)) NOT FINAL;
CREATE TYPE Student_t UNDER Person_t
( deptid NUMBER,
major VARCHAR2(30)) NOT FINAL;
CREATE TYPE Employee_t UNDER Person_t
( empid NUMBER,
mgr VARCHAR2(30));

Example 24-11

Contents of the Intype File

CASE=SAME
TYPE EMPLOYEE_T
TYPE STUDENT_T
TYPE PERSON_T

Example 24-12
Structs

OTT Generates C Structs for the Types and Null Indicator

#ifndef MYFILENAME_ORACLE
#define MYFILENAME_ORACLE
#ifndef OCI_ORACLE
#include 
#endif
typedef OCIRef EMPLOYEE_T_ref;
typedef OCIRef STUDENT_T_ref;
typedef OCIRef PERSON_T_ref;
struct PERSON_T
{
OCINumber SSN;
OCIString * NAME;
OCIString * ADDRESS;
};
typedef struct PERSON_T PERSON_T;
struct PERSON_T_ind
{
OCIInd _atomic;
OCIInd SSN;
OCIInd NAME;
OCIInd ADDRESS;

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Chapter 24

OTT Data Type Mappings

};
typedef struct PERSON_T_ind PERSON_T_ind;
struct EMPLOYEE_T
{
PERSON_T_ind;
OCINumber EMPID;
OCIString * MGR;
};
typedef struct EMPLOYEE_T EMPLOYEE_T;
struct EMPLOYEE_T_ind
{
PERSON_T _super;
OCIInd EMPID;
OCIInd MGR;
};
typedef struct EMPLOYEE_T_ind EMPLOYEE_T_ind;
struct STUDENT_T
{
PERSON_T _super;
OCINumber DEPTID;
OCIString * MAJOR;
};
typedef struct STUDENT_T STUDENT_T;
struct STUDENT_T_ind
{
PERSON_T _super;
OCIInd DEPTID;
OCIInd MAJOR;
};
typedef struct STUDENT_T_ind STUDENT_T_ind;
#endif

This section includes the following topic: Substitutable Object Attributes.

24.4.4.1 Substitutable Object Attributes
For attributes of NOT FINAL types (potentially substitutable), the embedded attribute is
represented as a pointer.
Consider a type Book_t created as follows:
CREATE TYPE Book_t AS OBJECT
( title VARCHAR2(30),
author Person_t
/* substitutable */);

The corresponding C struct generated by OTT contains a pointer to Person_t:
struct Book_t
{
OCIString *title;
Person_t *author;
}

/* pointer to Person_t struct */

The NULL indicator struct corresponding to the preceding type is as follows:

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Chapter 24

Outtype File

struct Book_t_ind
{
OCIInd _atomic;
OCIInd title;
OCIInd author;
}

Note that the NULL indicator struct corresponding to the author attribute can be obtained
from the author object itself. See OCIObjectGetInd().
If a type is defined to be FINAL, it cannot have any subtypes. An attribute of a FINAL
type is therefore not substitutable. In such cases, the mapping is as before: the
attribute struct is inline. Now, if the type is altered and defined to be NOT FINAL, the
mapping must change. The new mapping is generated by running OTT again.

See Also:
OCIObjectGetInd()

24.5 Outtype File
The outtype file is named on the OTT command line.
When OTT generates the C header file, it also writes the results of the translation into
the outtype file. This file contains an entry for each of the types that is translated,
including its version string, and the header file to which its C representation was
written.
The outtype file from one OTT run can be used as the intype file for a subsequent OTT
invocation.
For example, suppose that you have a simple intype file, as shown in Example 24-13,
which was used in Example 24-5.
The user has chosen to specify the case for the OTT-generated C identifiers, and has
provided a list of types to be translated. In two of these types, naming conventions are
specified.
Example 24-14 shows what the outtype file might look like after running OTT.
When examining the contents of the outtype file, you might discover types listed that
were not included in the intype specification. For example, suppose that the intype file
only specified that the person type was to be translated as follows:
CASE = LOWER
TYPE PERSON

However, because the definition of the person type includes an attribute of type
address, the outtype file includes entries for both PERSON and ADDRESS. The person type
cannot be translated completely without first translating address.
When the parameter TRANSITIVE has been set to TRUE (it is the default), OTT analyzes
the types in the intype file for type dependencies before performing the translation, and
translates other types as necessary.

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Example 24-13

Contents of an Intype File

CASE=LOWER
TYPE employee
TRANSLATE SALARY$ AS salary
DEPTNO AS department
TYPE ADDRESS
TYPE item
TYPE "Person"
TYPE PURCHASE_ORDER AS p_o

Example 24-14

Contents of the Outtype File After Running OTT

CASE = LOWER
TYPE EMPLOYEE AS employee
VERSION = "$8.0"
HFILE = demo.h
TRANSLATE SALARY$ AS salary
DEPTNO AS department
TYPE ADDRESS AS ADDRESS
VERSION = "$8.0"
HFILE = demo.h
TYPE ITEM AS item
VERSION = "$8.0"
HFILE = demo.h
TYPE "Person" AS Person
VERSION = "$8.0"
HFILE = demo.h
TYPE PURCHASE_ORDER AS p_o
VERSION = "$8.0"
HFILE = demo.h

24.6 About Using OTT with OCI Applications
An OCI application that accesses objects in an Oracle server can use C header and
implementation files that have been generated by OTT.
The header file is incorporated into the OCI code with an #include statement.
Once the header file has been included, the OCI application can access and
manipulate object data in the host language format.
Figure 24-1 shows the steps involved in using OTT with OCI for the simplest
applications:
1.

SQL is used to create type definitions in the database.

2.

OTT generates a header file containing C representations of object types and
named collection types. It also generates an implementation file, as named with
the INITFILE option.

3.

The application is written. User-written code in the OCI application declares and
calls the INITFUNC function.

4.

The header file is included in an OCI source code file.

5.

The OCI application, including the implementation file generated by OTT, is
compiled and linked with the OCI libraries.

6.

The OCI executable is run against the Oracle database.

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About Using OTT with OCI Applications

Figure 24-1

Using OTT with OCI

SQL DDL

OTT
Type
Definitions
#include
ORACLE
Database

Implementation
File

Header
File

OCI source
File

Compiler

Object File

OCI library

Object File

Linker

Executable

This section includes the following topics:
•

About Accessing and Manipulating Objects with OCI

•

Calling the Initialization Function

•

Tasks of the Initialization Function

24.6.1 About Accessing and Manipulating Objects with OCI
Within the application, the OCI program can perform bind and define operations using
program variables declared to be of types that appear in the OTT-generated header
file.
For example, an application might fetch a REF to an object using a SQL SELECT
statement and then pin that object using the appropriate OCI function. Once the object
has been pinned, its attribute data can be accessed and manipulated with other OCI
functions.
OCI includes a set of data type mapping and manipulation functions that are
specifically designed to work on attributes of object types and named collection types.
The following are examples of the available functions:
•

OCIStringSize() gets the size of an OCIString string.

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About Using OTT with OCI Applications

•

OCINumberAdd() adds two OCINumber numbers together.

•

OCILobIsEqual() compares two LOB locators for equality.

•

OCIRawPtr() gets a pointer to an OCIRaw raw data type.

•

OCICollAppend() appends an element to a collection type (OCIArray or OCITable).

•

OCITableFirst() returns the index for the first existing element of a nested table
(OCITable).

•

OCIRefIsNull() tests if a REF (OCIRef) is NULL.

These functions are described in detail in other chapters of this guide.

See Also:
•

OCIStringSize()

•

OCINumberAdd()

•

OCILobIsEqual()

•

OCIRawPtr()

•

OCICollAppend()

•

OCITableFirst()

•

OCIRefIsNull()

24.6.2 Calling the Initialization Function
OTT generates a C initialization function if requested. The initialization function tells
the environment, for each object type used in the program, which version of the type is
used.
You can specify a name for the initialization function when you invoke OTT with the
INITFUNC option, or you can allow OTT to select a default name based on the name of
the implementation file (INITFILE) containing the function.

The initialization function takes two arguments; an environment handle pointer and an
error handle pointer. There is typically a single initialization function, but this is not
required. If a program has several separately compiled pieces requiring different types,
you may want to execute OTT separately for each piece, requiring for each piece, one
initialization file containing an initialization function.
After an environment handle is created by an explicit OCI object call (for example, by
calling OCIEnvCreate()) you must also explicitly call the initialization functions. All the
initialization functions must be called for each explicitly created environment handle.
This gives each handle access to all the Oracle data types used in the entire program.
If an environment handle is implicitly created by embedded SQL statements, such as
EXEC SQL CONTEXT USE and EXEC SQL CONNECT, the handle is initialized implicitly, and the
initialization functions need not be called. This is only relevant when Pro*C/C++ is
being combined with OCI applications.
The following example shows an initialization function.

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Suppose that you have an intype file, ex2c.typ, containing the content shown in
Example 24-15.
Then you invoke OTT from the command line and specify the initialization function, as
shown in Example 24-16.
OTT generates the ex2cv.c file with the contents shown in Example 24-17.
The function ex2cv() creates the type version table and inserts the types BREN.PERSON
and BREN.ADDRESS.
If a program explicitly creates an environment handle, all the initialization functions
must be generated, compiled, and linked, because they must be called for each
explicitly created handle. If a program does not explicitly create any environment
handles, initialization functions are not required.
A program that uses an OTT-generated header file must also use the initialization
function generated at the same time. When a header file is generated by OTT and an
environment handle is explicitly created in the program, then the implementation file
must also be compiled and linked into the executable.
Example 24-15

Content of an Intype File Named ex2c.typ

TYPE BREN.PERSON
TYPE BREN.ADDRESS

Example 24-16

Invoking OTT and Specifying the Initialization Function

ott userid=bren intype=ex2c outtype=ex2co hfile=ex2ch.h initfile=ex2cv.c

Example 24-17

Content of an OTT-Generated File Named ex2cv.c

#ifndef OCI_ORACLE
#include 
#endif
sword ex2cv(OCIEnv *env, OCIError *err)
{
sword status = OCITypeVTInit(env, err);
if (status == OCI_SUCCESS)
status = OCITypeVTInsert(env, err,
"BREN", 5,
"PERSON", 6,
"$8.0", 4);
if (status == OCI_SUCCESS)
status = OCITypeVTInsert(env, err,
"BREN", 5,
"ADDRESS", 7,
"$8.0", 4);
return status;
}

See Also:
OCIEnvCreate()

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Chapter 24

OTT Reference

24.6.3 Tasks of the Initialization Function
The C initialization function supplies version information about the types processed by
OTT. It adds to the type-version table the name and version identifier of every OTTprocessed object data type.
The type-version table is used by the Oracle database type manager to determine
which version of a type a particular program uses. Different initialization functions
generated by OTT at different times can add some of the same types to the type
version table. When a type is added more than once, Oracle Database ensures that
the same version of the type is registered each time.
It is the OCI programmer's responsibility to declare a function prototype for the
initialization function, and to call the function.

Note:
In the current release of Oracle Database, each type has only one version.
Initialization of the type version table is required only for compatibility with
future releases of Oracle Database.

24.7 OTT Reference
Parameters that can appear on the OTT command line or in a CONFIG file control the
behavior of OTT. Certain parameters can also appear in the intype file.
This section provides detailed information about the following topics:
•

OTT Command-Line Syntax

•

OTT Parameters

•

Where OTT Parameters Can Appear

•

Structure of the Intype File

•

Nested Included File Generation

•

SCHEMA_NAMES Usage

•

Default Name Mapping

•

OTT Restriction on File Name Comparison

•

OTT Command on Microsoft Windows

The following conventions are used in this section to describe OTT syntax:
•

Italic strings are variables or parameters to be supplied by the user.

•

Strings in UPPERCASE are entered as shown, except that case is not significant.

•

OTT keywords are listed in a lowercase monospaced font in examples and
headings, but are printed in uppercase in text to make them more distinctive.

•

Square brackets [...] enclose optional items.

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OTT Reference

•

An ellipsis (...) immediately following an item (or items enclosed in brackets)
means that the item can be repeated any number of times.

•

Punctuation symbols other than those described earlier are entered as shown.
These include ".", "@", and so on.

24.7.1 OTT Command-Line Syntax
The OTT command-line interface is used when explicitly invoking OTT to translate
database types into C structs.
This is always required when you develop OCI applications that use objects.
An OTT command-line statement consists of the keyword OTT, followed by a list of OTT
parameters.
The parameters that can appear on an OTT command-line statement are as follows:
[userid=username/password[@db_name]]
[intype=filename]
outtype=filename
code=C|ANSI_C|KR_C
[hfile=filename]
[errtype=filename]
[config=filename]
[initfile=filename]
[initfunc=filename]
[case=SAME|LOWER|UPPER|OPPOSITE]
[schema_name=ALWAYS|IF_NEEDED|FROM_INTYPE]
[transitive=TRUE|FALSE]
[URL=url]

Note:
Generally, the order of the parameters following the ott command does not
matter. Only the OUTTYPE and CODE parameters are always required.

The HFILE parameter is almost always used. If omitted from the command line, HFILE
must be specified individually for each type in the intype file. If OTT determines that a
type not listed in the intype file must be translated, an error is reported. Therefore, it is
safe to omit the HFILE parameter only if the intype file was previously generated as an
OTT outtype file.
If the intype file is omitted, the entire schema is translated. The OTT parameter
descriptions are described in the sections that follow.

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OTT Reference

The following is an example of an OTT command-line statement (you are prompted for
the password):
ott userid=marc intype=in.typ outtype=out.typ code=c hfile=demo.h\
errtype=demo.tls case=lower

The following sections describe each of the OTT command-line parameters.

See Also:
OTT Parameters

24.7.2 OTT Parameters
Enter parameters on the OTT command line using the following format:
parameter=value

In this format, parameter is the literal parameter string and value is a valid parameter
setting. The literal parameter string is not case-sensitive.
Separate command-line parameters by using either spaces or tabs.
Parameters can also appear within a configuration file, but, in that case, no whitespace
is permitted within a line, and each parameter must appear on a separate line.
Additionally, the parameters CASE, HFILE,INITFUNC, and INITFILE can appear in the
intype file.
This section includes the following OTT parameters:
•

USERID

•

INTYPE

•

OUTTYPE

•

CODE

•

INITFILE

•

INITFUNC

•

HFILE

•

CONFIG

•

ERRTYPE

•

CASE

•

SCHEMA_NAMES

•

TRANSITIVE

•

URL

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24.7.2.1 USERID
The USERID parameter specifies the database user name, password, and optional
database name (Oracle Net Services database specification string).
If the database name is omitted, the default database is assumed. The syntax of this
parameter is:
userid=username/password[@db_name]

The USERID parameter is optional. If it is omitted, OTT automatically attempts to
connect to the default database as user OPS$username, where username is the user's
operating system user name. If this is the first parameter, "USERID=" and the password
and the database name can be omitted, as shown here:
ott username ...

For security purposes, when you enter only the user name you are prompted for the
rest of the entry.
The username and db_name (schema name) combination is appended and used as a key
in the OCIContextGetValue() call, which supports a maximum length of 64 bytes in
Oracle Database 12c Release 1 (12.1). In Oracle Database 12c Release 2 (12.2) this
max length is extended to support 243 bytes, not including 1 character for the period
(.).

24.7.2.2 INTYPE
The INTYPE parameter specifies the name of the file from which to read the list of object
type specifications. OTT translates each type in the list.
The syntax for this parameter is
intype=filename

"INTYPE=" can be omitted if USERID and INTYPE are the first two parameters, in that order,
and "USERID=" is omitted. If the INTYPE parameter is not specified, all types in the user's
schema are translated.
ott username filename...

The intype file can be thought of as a makefile for type declarations. It lists the types
for which C struct declarations are needed.
If the file name on the command line or in the intype file does not include an extension,
an operating system-specific extension such as "TYP" or ".typ" is added.

See Also:
Structure of the Intype File for a description of the format of the intype file

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OTT Reference

24.7.2.3 OUTTYPE
The OUTTYPE parameter specifies the name of a file into which OTT writes type
information for all the object data types it processes.
This includes all types explicitly named in the intype file, and can include additional
types that are translated because they are used in the declarations of other types that
must be translated (if TRANSITIVE=TRUE). This file must be used as an intype file in a
future invocation of OTT.
outtype=filename

If the INTYPE and OUTTYPE parameters refer to the same file, the new INTYPE parameter
information replaces the old information in the intype file. This provides a convenient
way for the same intype file to be used repeatedly in the cycle of altering types,
generating type declarations, editing source code, precompiling, compiling, and
debugging.
The parameter OUTTYPE must be specified.
If the file name on the command line or in the outtype file does not include an
extension, an operating system-specific extension such as "TYP" or ".typ" is added.

24.7.2.4 CODE
This is the desired host language for OTT output, which is specified as CODE=C,
CODE=KR_C, or CODE=ANSI_C.
"CODE=C" is equivalent to "CODE=ANSI_C".
CODE=C|KR_C|ANSI_C

There is no default value for this parameter; it must be supplied.

24.7.2.5 INITFILE
The INITFILE parameter specifies the name of the file where the OTT-generated
initialization file is to be written.
The initialization function is not generated if this parameter is omitted.
For Pro*C/C++ programs, the INITFILE is not necessary, because the SQLLIB runtime
library performs the necessary initializations. An OCI program user must compile and
link the INITFILE files, and must call the initialization file functions when an
environment handle is created.
If the file name of an INITFILE on the command line or in the intype file does not
include an extension, an operating system-specific extension such as "C" or ".c" is
added.
initfile=filename

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24.7.2.6 INITFUNC
The INITFUNC parameter is only used in OCI programs.
It specifies the name of the initialization function generated by OTT. If this parameter is
omitted, the name of the initialization function is derived from the name of the INITFILE.
initfunc=filename

24.7.2.7 HFILE
The HFILE parameter specifies the name of the include (.h) file to be generated by OTT
for the declarations of types that are mentioned in the intype file but whose include
files are not specified there.
This parameter is required unless the include file for each type is specified individually
in the intype file. This parameter is also required if a type not mentioned in the intype
file must be generated because other types require it, and these other types are
declared in two or more different files, and TRANSITIVE=TRUE.
If the file name of an HFILE on the command line or in the intype file does not include
an extension, an operating system-specific extension such as "H" or ".h" is added.
hfile=filename

24.7.2.8 CONFIG
The CONFIG parameter specifies the name of the OTT configuration file, which lists
commonly used parameter specifications.
Parameter specifications are also read from a system configuration file in an operating
system-dependent location. All remaining parameter specifications must appear on the
command line, or in the intype file.
config=filename

Note:
A CONFIG parameter is not allowed in the CONFIG file.

24.7.2.9 ERRTYPE
If the ERRTYPE parameter is supplied, OTT writes a listing of the intype file to the ERRTYPE
file, along with all informational and error messages.
Informational and error messages are sent to the standard output whether ERRTYPE
parameter is specified or not.
Essentially, the ERRTYPE file is a copy of the intype file with error messages added. In
most cases, an error message includes a pointer to the text that caused the error.
If the file name of an ERRTYPE on the command line or in the intype file does not include
an extension, an operating system-specific extension such as "TLS" or ".tls" is added.

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errtype=filename

24.7.2.10 CASE
This CASE parameter affects the case of certain C identifiers generated by OTT.
The possible values of CASE are SAME, LOWER, UPPER, and OPPOSITE. If CASE = SAME, the
case of letters is not changed when converting database type and attribute names to C
identifiers. If CASE=LOWER, all uppercase letters are converted to lowercase. If
CASE=UPPER, all lowercase letters are converted to uppercase. If CASE=OPPOSITE, all
uppercase letters are converted to lowercase, and vice versa.
CASE=[SAME|LOWER|UPPER|OPPOSITE]

This option affects only those identifiers (attributes or types not explicitly listed) not
mentioned in the intype file. Case conversion occurs after a legal identifier has been
generated.
Note that the case of the C struct identifier for a type specifically mentioned in the
INTYPE parameter option is the same as its case in the intype file. For example, if the
intype file includes the following line:
TYPE Worker

Then OTT generates the following line:
struct Worker {...};

However, suppose that the intype file is written as follows:
TYPE wOrKeR

Then OTT generates the following line, following the case specified in the intype file.
struct wOrKeR {...};

Case-insensitive SQL identifiers not mentioned in the intype file appear in uppercase if
CASE=SAME, and in lowercase if CASE=OPPOSITE. A SQL identifier is case-insensitive if it
was not enclosed in quotation marks when it was declared.

24.7.2.11 SCHEMA_NAMES
The SCHEMA_NAMES parameter offers control in qualifying the database name of a type
from the default schema with a schema name in the outtype file.
The outtype file generated by OTT contains information about the types processed by
OTT, including the type names.

See Also:
SCHEMA_NAMES Usage

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24.7.2.12 TRANSITIVE
The TRANSITIVE parameter takes the values TRUE (the default) or FALSE.
It indicates whether type dependencies not explicitly listed in the intype file are to be
translated or not.
If TRANSITIVE=TRUE is specified, then types needed by other types but not mentioned in
the intype file are generated.
If TRANSITIVE=FALSE is specified, then types not mentioned in the intype file are not
generated, even if they were used as attribute types of other generated types.

24.7.2.13 URL
For the URL parameter, OTT uses JDBC (Java Database Connectivity), the Java
interface for connecting to the database.
The default value of parameter URL is:
URL=jdbc:oracle:oci8:@

The OCI8 driver is for client-side use with an Oracle Database installation.
To specify the JDBC Thin driver (the Java driver for client-side use without an Oracle
Database installation), use the following URL parameter syntax:
URL=jdbc:oracle:thin:@host:port:sid

The host is the name of the host on which the database is running, port is the port
number, and sid is the Oracle SID.

24.7.3 Where OTT Parameters Can Appear
OTT parameters can appear on the command line, in a CONFIG file named on the
command line, or both.
Some parameters are also allowed in the intype file.
OTT is invoked as follows:
ott username/password parameters

If one of the parameters on the command line is the following, then additional
parameters are read from the configuration file filename:
config=filename

In addition, parameters are also read from a default configuration file in an operating
system-dependent location. This file must exist, but can be empty. Parameters in a
configuration file must appear one in each line, with no whitespace on the line.
If OTT is executed without any arguments, an online parameter reference is displayed.
The types for OTT to translate are named in the file specified by the INTYPE parameter.
The parameters CASE, INITFILE, INITFUNC, and HFILE can also appear in the intype file.
The outtype files generated by OTT include the CASE parameter, and include the

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INITFILE, and INITFUNC parameters if an initialization file was generated. The outtype
file specifies the HFILE individually for each type.

The case of the OTT command is operating system-dependent.

24.7.4 Structure of the Intype File
The intype and outtype files list the types translated by OTT, and provide all the
information needed to determine how a type or attribute name is translated to a legal C
identifier.
These files contain one or more type specifications. These files also can contain
specifications of the following options:
•

CASE

•

HFILE

•

INITFILE

•

INITFUNC

If the CASE, INITFILE, or INITFUNC options are present, they must precede any type
specifications. If these options appear both on the command line and in the intype file,
the value on the command line is used.
This section includes the following topic: Intype File Type Specifications.

See Also:
Outtype File for an example of a simple user-defined intype file, and of the
full outtype file that OTT generates from it

24.7.4.1 Intype File Type Specifications
A type specification in the intype file names an object data type that is to be translated.
A type specification in the outtype file names an object data type that has been
translated.
TYPE employee
TRANSLATE SALARY$ AS salary
DEPTNO AS department
TYPE ADDRESS
TYPE PURCHASE_ORDER AS p_o

The structure of a type specification is as follows, where [] indicates optional inputs
inside:
TYPE type_name [AS type_identifier]
[VERSION [=] version_string]
[HFILE [=] hfile_name]
[TRANSLATE{member_name [AS identifier]}...]

The syntax of type_name is:
[schema_name.]type_name

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The schema_name is the name of the schema that owns the given object data type, and
type_name is the name of the type. The default schema is that of the user running OTT.
The default database is the local database.
The components of a type specification are described as follows:
•

type_name is the name of an Oracle Database object data type.

•

type_identifier is the C identifier used to represent the type. If type_identifier is

omitted, the default name mapping algorithm is used.
•

version_string is the version string of the type that was used when the code was

generated by a previous invocation of OTT. The version string is generated by
OTT and written to the outtype file, which can be used as the intype file when OTT
is executed later. The version string does not affect the operation of OTT, but is
eventually used to select the version of the object data type that should be used in
the running program.
•

hfile_name is the name of the header file in which the declarations of the
corresponding struct or class appear. If hfile_name is omitted, the file named by
the command-line HFILE parameter is used if a declaration is generated.

•

member_name is the name of an attribute (data member) that is to be translated to
the identifier.

•

identifier is the C identifier used to represent the attribute in the user program.

Identifiers can be specified in this way for any number of attributes. The default
name mapping algorithm is used for the attributes that are not mentioned.
An object data type may need to be translated for one of two reasons:
•

It appears in the intype file.

•

It is required to declare another type that must be translated, and TRANSITIVE=TRUE.

If a type that is not mentioned explicitly is required by types declared in exactly one
file, OTT writes the translation of the required type to the same file or files as the
explicitly declared types that require it.
If a type that is not mentioned explicitly is required by types declared in two or more
different files, OTT writes the translation of the required type to the global HFILE file.

See Also:
Default Name Mapping for more information about naming the intype file
related to the version_string component.

24.7.5 Nested Included File Generation
Every HFILE generated by OTT uses #include directives to include other necessary
files and #define directives to define a symbol constructed from the name of the file,
which can be used to determine if the HFILE has been included.
Consider, for example, a database with the types shown in Example 24-18.
The intype file content is shown in Example 24-19.

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If you invoke OTT with the command shown in Example 24-20, then it generates the
header files shown in Example 24-21 and Example 24-22.
The content of the header file tott95b.h is shown in Example 24-21.
The content of the header file tott95a.h is shown in Example 24-22.
In Example 24-21, the symbol TOTT95B_ORACLE is defined first so that the programmer
can conditionally include tott95b.h without having to worry whether tott95b.h depends
on the include file using the construct, as shown in Example 24-23.
Using this technique, the programmer can include tott95b.h from some file, say foo.h,
without having to know whether some other file included by foo.h also includes
tott95b.h.
After the definition of the symbol TOTT95B_ORACLE, the file oci.h is included. Every HFILE
generated by OTT includes oci.h, which contains type and function declarations that
the Pro*C/C++ or OCI programmer can use. This is the only case in which OTT uses
angle brackets in an #include directive.
Next, the file tott95a.h is included. This file is included because it contains the
declaration of "struct px1", which tott95b.h requires. When the user's intype file
requests that type declarations be written to more than one file, OTT determines which
other files each HFILE must include, and generates the necessary #includes directives.
Note that OTT uses quotation marks in this #include directive. When a program
including tott95b.h is compiled, the search for tott95a.h begins where the source
program was found, and thereafter follows an implementation-defined search rule. If
tott95a.h cannot be found in this way, a complete file name (for example, a Linux or
UNIX absolute path name beginning with /) should be used in the intype file to specify
the location of tott95a.h.
Example 24-18
Include Files

Object Type Definition to Demonstrate How OTT Generates

create type px1 AS OBJECT (col1 number, col2 integer);
create type px2 AS OBJECT (col1 px1);
create type px3 AS OBJECT (col1 px1);

Example 24-19

Content of the Intype File

CASE=lower
type pxl
hfile tott95a.h
type px3
hfile tott95b.h

Example 24-20

Invoking OTT from the Command Line

ott scott tott95i.typ outtype=tott95o.typ code=c

Example 24-21

Content of the Header File tott95b.h

#ifndef TOTT95B_ORACLE
#define TOTT95B_ORACLE
#ifndef OCI_ORACLE
#include 
#endif
#ifndef TOTT95A_ORACLE
#include "tott95a.h"
#endif

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typedef OCIRef px3_ref;
struct px3
{
struct px1 col1;
};
typedef struct px3 px3;
struct px3_ind
{
OCIInd _atomic;
struct px1_ind col1
};
typedef struct px3_ind px3_ind;
#endif

Example 24-22

Content of the Header File tott95a.h

#ifndef TOTT95A_ORACLE
#define TOTT95A_ORACLE
#ifndef OCI_ORACLE
#include 
#endif
typedef OCIRef px1_ref;
struct px1
{
OCINumber col1;
OCINumber col2;
}
typedef struct px1 px1;
struct px1_ind
{
OCIInd _atomic;
OCIInd col1;
OCIInd col2;
}
typedef struct px1_ind px1_ind;
#endif

Example 24-23
tott95b.h

Construct to Use to Conditionally Include the Header File

#ifndef TOTT95B_ORACLE
#include "tott95b.h"
#endif

24.7.6 SCHEMA_NAMES Usage
The SCHEMA_NAMES parameter affects whether the name of a type from the default
schema to which OTT is connected is qualified with a schema name in the outtype file.
This parameter affects whether the name of a type from the default schema to which
OTT is connected is qualified with a schema name in the outtype file.
The name of a type from a schema other than the default schema is always qualified
with a schema name in the outtype file.
The schema name, or its absence, determines in which schema the type is found
during program execution.
There are three settings:
•

schema_names=ALWAYS (default)

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All type names in the outtype file are qualified with a schema name.
•

schema_names=IF_NEEDED

The type names in the outtype file that belong to the default schema are not
qualified with a schema name. As always, type names belonging to other schemas
are qualified with the schema name.
•

schema_names=FROM_INTYPE

A type mentioned in the intype file is qualified with a schema name in the outtype
file if, and only if, it was qualified with a schema name in the intype file. A type in
the default schema that is not mentioned in the intype file but that must be
generated because of type dependencies is written with a schema name only if the
first type encountered by OTT that depends on it was written with a schema name.
However, a type that is not in the default schema to which OTT is connected is
always written with an explicit schema name.
The outtype file generated by OTT is an input parameter to Pro*C/C++. From the point
of view of Pro*C/C++, it is the Pro*C/C++ intype file. This file matches database type
names to C struct names. This information is used at runtime to ensure that the correct
database type is selected into the struct. If a type appears with a schema name in the
outtype file (Pro*C/C++ intype file), the type is found in the named schema during
program execution. If the type appears without a schema name, the type is found in
the default schema to which the program connects, which can be different from the
default schema that OTT used.
This section includes the following topic: Example: Schema_Names Usage.

24.7.6.1 Example: Schema_Names Usage
Shows examples of using SCHEMA_NAMES parameter.
Suppose that SCHEMA_NAMES is set to FROM_INTYPE, and the intype file reads as follows:
TYPE Person
TYPE david.Dept
TYPE sam.Company

Then the Pro*C/C++ application that uses the OTT-generated structs uses the types
sam.Company, david.Dept, and Person. Using Person without a schema name refers to the
Person type in the schema to which the application is connected.
If OTT and the application both connect to schema david, the application uses the
same type (david.Person) that OTT used. If OTT connected to schema david but the
application connects to schema jana, the application uses the type jana.Person. This
behavior is appropriate only if the same "CREATE TYPE Person" statement has been
executed in schema david and schema jana.
In contrast, the application uses type david.Dept regardless of to which schema the
application is connected. If this is the behavior that you want, be sure to include
schema names with your type names in the intype file.
In some cases, OTT translates a type that the user did not explicitly name. For
example, consider the following SQL declarations:
CREATE TYPE
( street
city
state

Address AS OBJECT
VARCHAR2(40),
VARCHAR(30),
CHAR(2),

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zip_code CHAR(10) );
CREATE TYPE Person AS OBJECT
( name
CHAR(20),
age
NUMBER,
addr
ADDRESS );

Now suppose that OTT connects to schema david, SCHEMA_NAMES=FROM_INTYPE is
specified, and the user's intype files include either TYPE Person or TYPE david.Person.
However, the intype file does not mention the type david.Address, which is used as a
nested object type in type david.Person. If "TYPE david.Person" appeared in the intype
file, then "TYPE david.Person" and "TYPE david.Address" appear in the outtype file. If
"Type Person" appeared in the intype file, then "TYPE Person" and "TYPE Address" appear
in the outtype file.
If the david.Address type is embedded in several types translated by OTT, but is not
explicitly mentioned in the intype file, the decision of whether to use a schema name is
made the first time OTT encounters the embedded david.Address type. If, for some
reason, the user wants type david.Address to have a schema name but does not want
type Person to have one, the user should explicitly specify the following in the intype
file:
TYPE

david.Address

In the usual case in which each type is declared in a single schema, it is safest for the
user to qualify all type names with schema names in the intype file.

24.7.7 Default Name Mapping
When OTT creates a C identifier name for an object type or attribute, it translates the
name from the database character set to a legal C identifier.
First, the name is translated from the database character set to the character set used
by OTT. Next, if a translation of the resulting name is supplied in the intype file, that
translation is used. Otherwise, OTT translates the name character-by-character to the
compiler character set, applying the CASE option. The following describes this process
in more detail.
When OTT reads the name of a database entity, the name is automatically translated
from the database character set to the character set used by OTT. In order for OTT to
read the name of the database entity successfully, all the characters of the name must
be found in the OTT character set, although a character can have different encodings
in the two character sets.
The easiest way to guarantee that the character set used by OTT contains all the
necessary characters is to make it the same as the database character set. Note,
however, that the OTT character set must be a superset of the compiler character set.
That is, if the compiler character set is 7-bit ASCII, the OTT character set must include
7-bit ASCII as a subset, and if the compiler character set is 7-bit EBCDIC, the OTT
character set must include 7-bit EBCDIC as a subset. The user specifies the character
set that OTT uses by setting the NLS_LANG environment variable, or by some other
operating system-specific mechanism.
Once OTT has read the name of a database entity, it translates the name from the
character set used by OTT to the compiler's character set. If a translation of the name
appears in the intype file, OTT uses that translation.

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Otherwise, OTT attempts to translate the name by using the following steps:
1.

If the OTT character set is a multibyte character set, all multibyte characters in the
name that have single-byte equivalents are converted to those single-byte
equivalents.

2.

The name is converted from the OTT character set to the compiler character set.
The compiler character set is a single-byte character set such as US7ASCII.

3.

The case of letters is set according to the CASE option in effect, and any character
that is not legal in a C identifier, or that has no translation in the compiler character
set, is replaced by an underscore. If at least one character is replaced by an
underscore, OTT gives a warning message. If all the characters in a name are
replaced by underscores, OTT gives an error message.

Character-by-character name translation does not alter underscores, digits, or singlebyte letters that appear in the compiler character set, so legal C identifiers are not
altered.
Name translation can, for example, translate accented single-byte characters such as
"o" with an umlaut or "a" with an accent grave to "o" or "a", and can translate a
multibyte letter to its single-byte equivalent. Name translation typically fails if the name
contains multibyte characters that lack single-byte equivalents. In this case, the user
must specify name translations in the intype file.
OTT does not detect a naming clash caused by two or more database identifiers being
mapped to the same C name, nor does it detect a naming problem where a database
identifier is mapped to a C keyword.

24.7.8 OTT Restriction on File Name Comparison
Currently, OTT determines if two files are the same by comparing the file names
provided by the user on the command line or in the intype file.
But one potential problem can occur when OTT needs to know if two file names refer
to the same file. For example, if the OTT-generated file foo.h requires a type
declaration written to foo1.h, and another type declaration written to /private/elias/
foo1.h, OTT should generate one #include directive if the two files are the same, and
two #includes directives if the files are different. In practice, though, it would conclude
that the two files are different, and would generate two #includes directives, as follows:
#ifndef FOO1_ORACLE
#include "foo1.h"
#endif
#ifndef FOO1_ORACLE
#include "/private/elias/foo1.h"
#endif

If foo1.h and /private/elias/foo1.h are different files, only the first one is included. If
foo1.h and /private/elias/foo1.h are the same file, a redundant #include directive is
written.
Therefore, if a file is mentioned several times on the command line or in the intype file,
each mention of the file should use exactly the same file name.

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24.7.9 OTT Command on Microsoft Windows
OTT executable on Microsoft Windows in the current release is ott.bat, instead of
ott.exe as in the earlier releases.
This may break Windows batch scripts, as the scripts exit immediately after executing
ott. To fix this problem, OTT should be invoked as follows, in Windows batch scripts:
call ott [arguments]

Note:
ORACLE_HOME\precomp\admin\ott.exe can be used until the scripts are fixed, as

an intermediate solution. However, this intermediate solution will not be
provided in future releases.

24-38

25
Oracle Database Access C API
This chapter begins to describe the Oracle Database Access C API and in particular
the OCI relational functions for C.
This chapter includes information about calling OCI functions in your application, along
with detailed descriptions of each function call.

See Also:
For code examples, see the demonstration programs included with your
Oracle Database installation. For additional information, see OCI
Demonstration Programs.

This chapter contains these topics:
•

Introduction to the Relational Functions

•

Connect, Authorize, and Initialize Functions

•

Handle and Descriptor Functions

•

Bind, Define, and Describe Functions

25.1 Introduction to the Relational Functions
Introduces OCI relational function calls.
This chapter and More Oracle Database Access C API describe the OCI relational
function calls and cover the functions in the basic OCI.

See Also:
Error Handling in OCI for information about return codes and error handling

25.1.1 Conventions for OCI Functions
Introduces the conventions used for OCI functions.
For each function, the following information is listed:

25.1.2 Purpose
What is the functions purpose?
A brief description of the action performed by the function.

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25.1.3 Syntax
What is the function declaration?
The function declaration.

25.1.4 Parameters
A description of each of the function's parameters and their modes.
This description includes the parameter's mode. The mode of a parameter has three
possible values, as described in Table 25-1.
Table 25-1

Mode of a Parameter

Mode

Description

IN

A parameter that passes data to the OCI

OUT

A parameter that receives data from the OCI on this call

IN/OUT

A parameter that passes data on the call and receives data on the
return from this or a subsequent call

25.1.5 Comments
Describes more detailed information about the function (if available).
This information may include restrictions on the use of the function, or other
information that might be useful when using the function in an application.

25.1.6 Returns
This optional section describes the possible values that can be returned.
This section can be found either before or after the Comments section.

25.1.7 Example
Provides acomplete or partial code example demonstrating the use of the function call
being described.
Not all function descriptions include an example.

25.1.8 Related Functions
Shows a list of related function calls to the function if applicable.
A list of related function calls.

25.1.9 About Calling OCI Functions
Provides useful information about calling OCI functions.

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Unlike earlier versions of OCI, in and after release 8, you cannot pass -1 for the string
length parameter of a NULL-terminated string. When you pass string lengths as
parameters, do not include the NULL terminator byte in the length. The OCI does not
expect strings to be NULL-terminated.
Buffer lengths that are OCI parameters are in bytes, with the following exceptions:
•

The amount parameters in some LOB calls are in characters

•

When UTF-16 encoding of text is used in function parameters, the length is in
character points

25.1.10 Server Round-Trips for LOB Functions
Indicates the number of server round-trips required for individual OCI LOB functions.
For a table showing the number of server round-trips required for individual OCI LOB
functions, see OCI Function Server Round-Trips.

25.2 Connect, Authorize, and Initialize Functions
Lists and describes connect, authorize, and initialize functions.
Table 25-1 describes the OCI connect, authorize, and initialize functions that are
described in this section.
Table 25-2

Connect, Authorize, and Initialize Functions

Function

Purpose

OCIAppCtxClearAll()

Clear all attribute-value information in a
namespace of an application context

OCIAppCtxSet()

Set an attribute and its associated value
in a namespace of an application context

OCIConnectionPoolCreate()

Initialize the connection pool

OCIConnectionPoolDestroy()

Destroy the connection pool

OCIDBShutdown()

Shut down Oracle Database

OCIDBStartup()

Start an Oracle Database instance

OCIEnvCreate()

Create and initialize an OCI environment
handle

OCIEnvNlsCreate()

Create and initialize an environment
handle for OCI functions to work under.
Enable you to set character set ID and
national character set ID at environment
creation time.

OCILogoff()

Release a session that was retrieved
using OCILogon2() or OCILogon()

OCILogon()

Simplify single-session logon

OCILogon2()

Create a logon session in various modes

OCIRequestDisableReplay()

Disables application continuity replay for
a session for the duration of the current
database request.

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Table 25-2

(Cont.) Connect, Authorize, and Initialize Functions

Function

Purpose

OCIServerAttach()

Attach to a server; initialize server
context handle

OCIServerDetach()

Detach from a server; uninitialize server
context handle

OCISessionBegin()

Authenticate a user

OCISessionEnd()

Terminate a user session

OCISessionGet()

Get a session from a session pool

OCISessionPoolCreate()

Initialize a session pool

OCISessionPoolDestroy()

Destroy a session pool

OCISessionRelease()

Release a session

OCITerminate()

Detach from a shared memory
subsystem

25.2.1 OCIAppCtxClearAll()
Clears all attribute-value information in a namespace of an application context.
Purpose
Clears all attribute-value information in a namespace of an application context.
Syntax
sword OCIAppCtxClearAll ( void
*sesshndl,
void
*nsptr,
ub4
nsptrlen,
OCIError *errhp,
ub4
mode ;

Parameters
sesshndl (IN/OUT)
Pointer to a session handle.
nsptr (IN)
Pointer to the namespace string (currently only CLIENTCONTEXT).
nsptrlen (IN)
Length of the namespace string.
errhp (OUT)
An error handle that can be passed to OCIErrorGet().
mode (IN)
Mode (OCI_DEFAULT is the default).
Returns
Returns an error number.

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Comments
This cleans up the context information on the server side during the next call to the
server. This namespace information is cleared from the session handle after the
information has been sent to the server and must be set up again if needed.
Related Topics
•

OCIAppCtxSet()
Sets an attribute and its associated value in a namespace of an application
context.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.2 OCIAppCtxSet()
Sets an attribute and its associated value in a namespace of an application context.
Purpose
Sets an attribute and its associated value in a namespace of an application context.
Syntax
sword OCIAppCtxSet ( void
void
ub4
void
ub4
void
ub4
OCIError
ub4

*sesshndl,
*nsptr,
nsptrlen,
*attrptr,
attrptrlen,
*valueptr,
valueptrlen,
*errhp,
mode );

Parameters
sesshndl (IN/OUT)
Pointer to a session handle.
nsptr (IN)
Pointer to the namespace string (currently only CLIENTCONTEXT).
nsptrlen (IN)
Length of the namespace string.
attrptr (IN)
Pointer to the attribute string.
attrptrlen (IN)
The length of the string pointed to by attrptr.
valueptr (IN)
Pointer to the value string.
valueptrlen (IN)
The length of the string pointed to by valueptr.

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errhp (OUT)
An error handle that can be passed to OCIErrorGet().
mode (IN)
Mode (OCI_DEFAULT is the default).
Returns
Returns an error number.
Comments
The information set on the session handle is sent to the server during the next call to
the server.
This information is cleared from the session handle after the information has been sent
to the server and must be set up again if needed.
Related Topics
•

OCIAppCtxClearAll()
Clears all attribute-value information in a namespace of an application context.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.3 OCIConnectionPoolCreate()
Initializes the connection pool.
Purpose
Initializes the connection pool.
Syntax
sword OCIConnectionPoolCreate ( OCIEnv
OCIError
OCICPool
OraText
sb4
const OraText
sb4
ub4
ub4
ub4
const OraText
sb4
const OraText
sb4
ub4

*envhp,
*errhp,
*poolhp,
**poolName,
*poolNameLen,
*dblink,
dblinkLen,
connMin,
connMax,
connIncr,
*poolUsername,
poolUserLen,
*poolPassword,
poolPassLen,
mode );

Parameters
envhp (IN)
A pointer to the environment where the connection pool is to be created
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet().

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poolhp (IN)
An allocated pool handle.
poolName (OUT)
The name of the connection pool connected to.
poolNameLen (OUT)
The length of the string pointed to by poolName.
dblink (IN)
Specifies the database (server) to connect to.
dblinkLen (IN)
The length of the string pointed to by dblink.
connMin (IN)
Specifies the minimum number of connections in the connection pool. Valid values
are 0 and higher.
These connections are opened to the server by OCIConnectionPoolCreate(). After the
connection pool is created, connections are opened only when necessary. Generally,
this parameter should be set to the number of concurrent statements that the
application is planning or expecting to run.
connMax (IN)
Specifies the maximum number of connections that can be opened to the database.
After this value is reached, no more connections are opened. Valid values are 1 and
higher.
connIncr (IN)
Allows the application to set the next increment for connections to be opened to the
database if the current number of connections is less than connMax. Valid values are 0
and higher.
poolUsername (IN)
Connection pooling requires an implicit primary session. This attribute provides a user
name for that session.
poolUserLen (IN)
The length of poolUsername.
poolPassword (IN)
The password for the user name poolUsername.
poolPassLen (IN)
The length of poolPassword.
mode (IN)
The modes supported are:
•

OCI_DEFAULT

•

OCI_CPOOL_REINITIALIZE

Ordinarily, OCIConnectionPoolCreate() is called with mode set to OCI_DEFAULT.
To change the pool attributes dynamically (for example, to change the connMin,
connMax, and connIncr parameters), call OCIConnectionPoolCreate() with mode set to
OCI_CPOOL_REINITIALIZE. When this is done, the other parameters are ignored.

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Comments
The OUT parameters poolName and poolNameLen contain values to be used in
subsequent OCIServerAttach() and OCILogon2() calls in place of the database name
and the database name length arguments.
Related Topics
•

OCIConnectionPoolDestroy()
Destroys the connection pool.

•

OCILogon2()
Gets a session.

•

OCIServerAttach()
Creates an access path to a data source for OCI operations.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Connection Pool Handle Attributes
Lists and describes connection pool handle attributes.

25.2.4 OCIConnectionPoolDestroy()
Destroys the connection pool.
Purpose
Destroys the connection pool.
Syntax
sword OCIConnectionPoolDestroy ( OCICPool
OCIError
ub4

*poolhp,
*errhp,
mode );

Parameters
poolhp (IN)
A pool handle for which a pool has been created.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet().
mode (IN)
Currently, this function supports only the OCI_DEFAULT mode.
Related Topics
•

OCIConnectionPoolCreate()
Initializes the connection pool.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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25.2.5 OCIDBShutdown()
Shuts down an Oracle Database instance.
Purpose
Shuts down an Oracle Database instance.
Syntax
sword OCIDBShutdown ( OCISvcCtx
OCIError
OCIAdmin
ub4

*svchp,
*errhp,
*admhp,
mode);

Parameters
svchp (IN)
A handle to a service context. There must be a valid server handle and a valid user
handle set in svchp.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet() for diagnostic information when
there is an error.
admhp (IN) - Optional
An instance administration handle. Currently not used; pass (OCIAdmin *)0.
mode (IN)
OCI_DEFAULT - Further connects are prohibited. Waits for users to disconnect from the

database.
OCI_DBSHUTDOWN_TRANSACTIONAL - Further connects are prohibited and no new

transactions are allowed. Waits for active transactions to complete.
OCI_DBSHUTDOWN_TRANSACTIONAL_LOCAL - Further connects are prohibited and no new

transactions are allowed. Waits only for local transactions to complete.
OCI_DBSHUTDOWN_IMMEDIATE - Does not wait for current calls to complete or users to

disconnect from the database. All uncommitted transactions are terminated and rolled
back.
OCI_DBSHUTDOWN_FINAL - Shuts down the database. Should be used only in the second
call to OCIDBShutdown() after the database is closed and dismounted.
OCI_DBSHUTDOWN_ABORT - Does not wait for current calls to complete or users to
disconnect from the database. All uncommitted transactions are terminated and are
not rolled back. This is the fastest possible way to shut down the database, but the
next database startup may require instance recovery. Therefore, this option should be
used only in unusual circumstances; for example, if a background process terminates
abnormally.
Comments
To do a shut down, you must be connected to the database as SYSOPER or SYSDBA. You
cannot be connected to a shared server through a dispatcher. When shutting down in
any mode other than OCI_DBSHUTDOWN_ABORT, use the following procedure:
1.

Call OCIDBShutdown() in OCI_DEFAULT, OCI_DBSHUTDOWN_TRANSACTIONAL,
OCI_DBSHUTDOWN_TRANSACTIONAL_LOCAL, or OCI_DBSHUTDOWN_IMMEDIATE mode to prohibit
further connects.

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2.

Issue the necessary ALTER DATABASE commands to close and dismount the
database.

3.

Call OCIDBShutdown() in OCI_DBSHUTDOWN_FINAL mode to shut down the instance.

Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIDBStartup()
Starts an Oracle Database instance.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Database Startup and Shutdown
This chapter describes topics about OCI database startup and shutdown.

25.2.6 OCIDBStartup()
Starts an Oracle Database instance.
Purpose
Starts an Oracle Database instance.
Syntax
sword OCIDBStartup ( OCISvcCtx
OCIError
OCIAdmin
ub4
ub4

*svchp,
*errhp,
*admhp,
mode,
flags);

Parameters
svchp (IN)
A handle to a service context. There must be a valid server handle and user handle
set in svchp.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet() for diagnostic information when
there is an error.
admhp (IN) - Optional
An instance administration handle. Use to pass additional arguments to the startup
call, or pass (OCIAdmin *)0 if you do not set OCI_ATTR_ADMIN_PFILE.
mode (IN)
OCI_DEFAULT - This is the only supported mode. It starts the instance, but does not
mount or open the database. Same as STARTUP NOMOUNT.

flags (IN)
OCI_DEFAULT - Allows database access to all users.
OCI_DBSTARTUPFLAG_RESTRICT - Allows database access only to users with both the
CREATE SESSION and RESTRICTED SESSION privileges (normally, the DBA).

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OCI_DBSTARTUPFLAG_FORCE - Shuts down a running instance (if there is any) using ABORT

before starting a new one. This mode should be used only in unusual circumstances.
Comments
You must be connected to the database as SYSOPER or SYSDBA in OCI_PRELIM_AUTH mode.
You cannot be connected to a shared server through a dispatcher (that is, when you
restart a running instance with OCI_DBSTARTUPFLAG_FORCE). To use a client-side
parameter file (pfile), OCI_ATTR_ADMIN_PFILE must be set in the administration handle;
otherwise, a server-side parameter file (spfile) is used. A call to OCIDBStartup() starts
one instance on the server.
Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIDBShutdown()
Shuts down an Oracle Database instance.

•

OCIServerAttach()
Creates an access path to a data source for OCI operations.

•

OCISessionBegin()
Creates a user session and begins a user session for a given server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Database Startup and Shutdown
This chapter describes topics about OCI database startup and shutdown.

25.2.7 OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.
Purpose
Creates and initializes an environment handle for OCI functions to work under.
Syntax
sword OCIEnvCreate

( OCIEnv
ub4
const void
const void

const void

const void

size_t
void

**envhpp,
mode,
*ctxp,
*(*malocfp)
(void *ctxp,
size_t size),
*(*ralocfp)
(void *ctxp,
void *memptr,
size_t newsize),
(*mfreefp)
(void *ctxp,
void *memptr))
xtramemsz,
**usrmempp );

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Parameters
envhpp (OUT)
A pointer to an environment handle whose encoding setting is specified by mode. The
setting is inherited by statement handles derived from envhpp.
mode (IN)
Specifies initialization of the mode. Valid modes are:
•

OCI_DEFAULT - The default value, which is non-UTF-16 encoding.

•

OCI_THREADED - Uses threaded environment. Internal data structures not exposed to

the user are protected from concurrent accesses by multiple threads.
•

OCI_OBJECT - Uses object features.

•

OCI_EVENTS - Uses publish-subscribe notifications.

•

OCI_NO_UCB - Suppresses the calling of the dynamic callback routine
OCIEnvCallback(). The default behavior is to allow calling of OCIEnvCallback() when

the environment is created.

See Also:
"Dynamic Callback Registrations"
•

OCI_ENV_NO_MUTEX - No mutual exclusion (mutex) locking occurs in this mode. All

OCI calls done on the environment handle, or on handles derived from the
environment handle, must be serialized. OCI_THREADED must also be specified when
OCI_ENV_NO_MUTEX is specified.
•

OCI_SUPPRESS_NLS_VALIDATION - Suppresses NLS character validation; NLS

character validation suppression is on by default beginning with Oracle Database
11g Release 1 (11.1). Use OCI_ENABLE_NLS_VALIDATION to enable NLS character
validation. See Comments for more information.
•

OCI_NEW_LENGTH_SEMANTICS - Byte-length semantics is used consistently for all

handles, regardless of character sets.
•

OCI_NCHAR_LITERAL_REPLACE_ON - Turns on N' substitution.

•

OCI_NCHAR_LITERAL_REPLACE_OFF - Turns off N' substitution. If neither this mode nor
OCI_NCHAR_LITERAL_REPLACE_ON is used, the substitution is determined by the
environment variable ORA_NCHAR_LITERAL_REPLACE, which can be set to TRUE or FALSE.
When it is set to TRUE, the replacement is turned on; otherwise it is turned off,

which is the default setting in OCI.
•

OCI_ENABLE_NLS_VALIDATION - Enables NLS character validation. See Comments for

more information.
ctxp (IN)
Specifies the user-defined context for the memory callback routines.
malocfp (IN)
Specifies the user-defined memory allocation function. If mode is OCI_THREADED, this
memory allocation routine must be thread-safe.

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ctxp (IN)
Specifies the context pointer for the user-defined memory allocation function.
size (IN)
Specifies the size of memory to be allocated by the user-defined memory allocation
function.
ralocfp (IN)
Specifies the user-defined memory reallocation function. If the mode is OCI_THREADED,
this memory allocation routine must be thread-safe.
ctxp (IN)
Specifies the context pointer for the user-defined memory reallocation function.
memptr (IN)
Pointer to memory block.
newsize (IN)
Specifies the new size of memory to be allocated.
mfreefp (IN)
Specifies the user-defined memory free function. If the mode is OCI_THREADED, this
memory free routine must be thread-safe.
ctxp (IN)
Specifies the context pointer for the user-defined memory free function.
memptr (IN)
Pointer to memory to be freed.
xtramemsz (IN)
Specifies the amount of user memory to be allocated for the duration of the
environment.
usrmempp (OUT)
Returns a pointer to the user memory of size xtramemsz allocated by the call for the
user.
Comments
This call creates an environment for all the OCI calls using the modes specified by the
user.

Note:
This call should be invoked before any other OCI call and should be used
instead of the OCIInitialize() call.

This call returns an environment handle, which is then used by the remaining OCI
functions. There can be multiple environments in OCI, each with its own environment
modes. This function also performs any process level initialization if required by any
mode. For example, if you want to initialize an environment as OCI_THREADED, then all
libraries that are used by OCI are also initialized in the threaded mode.

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If N' substitution is turned on, the OCIStmtPrepare2() function performs the N'
substitution on the SQL text and stores the resulting SQL text in the statement handle.
Thus, if the application uses OCI_ATTR_STATEMENT to retrieve the SQL text from the OCI
statement handle, the modified SQL text, instead of the original SQL text, is returned.
To turn on N' substitution in ksh shell:
export ORA_NCHAR_LITERAL_REPLACE=TRUE

To turn on N' substitution in csh shell:
setenv ORA_NCHAR_LITERAL_REPLACE TRUE

If a remote database is of a release before 10.2, N' substitution is not performed.
If you are writing a DLL or a shared library using the OCI library, then use this call
instead of the deprecated OCIInitialize() call.

See Also:
"User Memory Allocation" for more information about the xtramemsz
parameter and user memory allocation

Regarding OCI_SUPPRESS_NLS_VALIDATION and OCI_ENABLE_NLS_VALIDATION modes, by
default, when client and server character sets are identical, and client and server
releases are both Oracle Database 11g Release 1 (11.1) or later, OCI does not
validate character data in the interest of better performance. This means that if the
application inserts a character string with partial multibyte characters (for example, at
the end of a bind variable), then such strings could get persisted in the database as is.
Note that if either the client or the server release is older than Oracle Database 11g
Release 1 (11.1), then OCI does not allow partial characters.
The OCI_ENABLE_NLS_VALIDATION mode, which was the default until Oracle Database 10g
Release 2 (10.2), ensures that partial multibyte characters are not persisted in the
database (when client and server character sets are identical). If the application can
produce partial multibyte characters, and if the application can run in an environment
where the client and server character sets are identical, then Oracle recommends
using the OCI_ENABLE_NLS_VALIDATION mode explicitly in order to ensure that such partial
characters get stripped out.
Example
Creating a Thread-Safe OCI Environment with N' Substitution Turned On
OCIEnv *envhp;
...
/* Create a thread-safe OCI environment with N' substitution turned on. */
if(OCIEnvCreate((OCIEnv **)&envhp,
(ub4)OCI_THREADED | OCI_NCHAR_LITERAL_REPLACE_ON,
(void *)0, (void * (*)(void *, size_t))0,
(void * (*)(void *, void *, size_t))0,
(void (*)(void *, void *))0,
(size_t)0, (void **)0))
{
printf("Failed: OCIEnvCreate()\n");
return 1;

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}
...

Related Topics
•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIHandleFree()
Explicitly deallocates a handle

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCITerminate()
Detaches the process from the shared memory subsystem and releases the
shared memory.

•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

25.2.8 OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.
Purpose
This function is an enhanced version of the OCIEnvCreate() function.
Syntax
sword OCIEnvNlsCreate

( OCIEnv
ub4
void
void

void

void

size_t
void
ub2
ub2

**envhpp,
mode,
*ctxp,
*(*malocfp)
(void *ctxp,
size_t size),
*(*ralocfp)
(void *ctxp,
void *memptr,
size_t newsize),
(*mfreefp)
(void *ctxp,
void *memptr))
xtramemsz,
**usrmempp
charset,
ncharset );

Parameters
envhpp (OUT)
A pointer to an environment handle whose encoding setting is specified by mode. The
setting is inherited by statement handles derived from envhpp.
mode (IN)
Specifies initialization of the mode. Valid modes are:
•

OCI_DEFAULT - The default value, which is non-UTF-16 encoding.

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•

OCI_THREADED - Uses threaded environment. Internal data structures not exposed to

the user are protected from concurrent accesses by multiple threads.
•

OCI_OBJECT - Uses object features.

•

OCI_EVENTS - Uses publish-subscribe notifications.

•

OCI_NO_UCB - Suppresses the calling of the dynamic callback routine
OCIEnvCallback(). The default behavior is to allow calling of OCIEnvCallback() when

the environment is created.

See Also:
Dynamic Callback Registrations
•

OCI_ENV_NO_MUTEX - No mutual exclusion (mutex) locking occurs in this mode. All

OCI calls done on the environment handle, or on handles derived from the
environment handle, must be serialized. OCI_THREADED must also be specified when
OCI_ENV_NO_MUTEX is specified.
•

OCI_SUPPRESS_NLS_VALIDATION - Suppresses NLS character validation; NLS

character validation suppression is on by default beginning with Oracle Database
11g Release 1 (11.1). Use OCI_ENABLE_NLS_VALIDATION to enable NLS character
validation. See Comments for more information.
•

OCI_NCHAR_LITERAL_REPLACE_ON - Turns on N' substitution.

•

OCI_NCHAR_LITERAL_REPLACE_OFF - Turns off N' substitution. If neither this mode nor
OCI_NCHAR_LITERAL_REPLACE_ON is used, the substitution is determined by the
environment variable ORA_NCHAR_LITERAL_REPLACE, which can be set to TRUE or FALSE.
When it is set to TRUE, the replacement is turned on; otherwise it is turned off, the

default setting in OCI.
•

OCI_ENABLE_NLS_VALIDATION - Enables NLS character validation. See Comments for

more information.
ctxp (IN)
Specifies the user-defined context for the memory callback routines.
malocfp (IN)
Specifies the user-defined memory allocation function. If mode is OCI_THREADED, this
memory allocation routine must be thread-safe.
ctxp (IN)
Specifies the context pointer for the user-defined memory allocation function.
size (IN)
Specifies the size of memory to be allocated by the user-defined memory allocation
function.
ralocfp (IN)
Specifies the user-defined memory reallocation function. If the mode is OCI_THREADED,
this memory allocation routine must be thread-safe.
ctxp (IN)
Specifies the context pointer for the user-defined memory reallocation function.

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memptr (IN)
Pointer to memory block.
newsize (IN)
Specifies the new size of memory to be allocated.
mfreefp (IN)
Specifies the user-defined memory free function. If the mode is OCI_THREADED, this
memory free routine must be thread-safe.
ctxp (IN)
Specifies the context pointer for the user-defined memory free function.
memptr (IN)
Pointer to memory to be freed.
xtramemsz (IN)
Specifies the amount of user memory to be allocated for the duration of the
environment.
usrmempp (OUT)
Returns a pointer to the user memory of size xtramemsz allocated by the call for the
user.
charset (IN)
The client-side character set for the current environment handle. If it is 0, the NLS_LANG
setting is used. OCI_UTF16ID is a valid setting; it is used by the metadata and the CHAR
data.
ncharset (IN)
The client-side national character set for the current environment handle. If it is 0,
NLS_NCHAR setting is used. OCI_UTF16ID is a valid setting; it is used by the NCHAR data.
Returns
OCI_SUCCESS - Environment handle has been successfully created.
OCI_ERROR - An error occurred.

Comments
This call creates an environment for all the OCI calls using the modes you specify.
After you use OCIEnvNlsCreate() to create the environment handle, the actual lengths
and returned lengths of bind and define handles are always expressed in number of
bytes. This applies to the following calls:
•

OCIBindByName() and OCIBindByName2()

•

OCIBindByPos() and OCIBindByPos2()

•

OCIBindDynamic()

•

OCIDefineByPos() and OCIDefineByPos2()

•

OCIDefineDynamic()

This function enables you to set charset and ncharset IDs at environment creation
time. It is an enhanced version of the OCIEnvCreate() function.

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OCIEnvNlsCreate() must be called with charset and ncharset either both zero or both
non-zero. Failure to do so results in an error (ORA-24820).

This function sets nonzero charset and ncharset as client-side database and national
character sets, replacing the ones specified by NLS_LANG and NLS_NCHAR. When charset
and ncharset are 0, the function behaves exactly the same as OCIEnvCreate().
Specifically, charset controls the encoding for metadata and data with implicit form
attribute, and ncharset controls the encoding for data with SQLCS_NCHAR form attribute.
Although OCI_UTF16ID can be set by OCIEnvNlsCreate(), it cannot be set in NLS_LANG or
NLS_NCHAR. To access the character set IDs in NLS_LANG and NLS_NCHAR, use
OCINlsEnvironmentVariableGet().
This call returns an environment handle, which is then used by the remaining OCI
functions. There can be multiple environments in OCI, each with its own environment
modes. This function also performs any process level initialization if required by any
mode. For example, if you want to initialize an environment as OCI_THREADED, then all
libraries that are used by OCI are also initialized in the threaded mode.
If N' substitution is turned on, the OCIStmtPrepare2() function performs the N'
substitution on the SQL text and stores the resulting SQL text in the statement handle.
Thus, if the application uses OCI_ATTR_STATEMENT to retrieve the SQL text from the OCI
statement handle, the modified SQL text, instead of the original SQL text, is returned.
To turn on N' substitution in ksh shell:
export ORA_NCHAR_LITERAL_REPLACE=TRUE

To turn on N' substitution in csh shell:
setenv ORA_NCHAR_LITERAL_REPLACE TRUE

If a remote database is of a release before 10.2, N' substitution is not performed.
If you are writing a DLL or a shared library using the OCI library, then use this call
instead of the deprecated OCIInitialize() call.

See Also:
•

User Memory Allocation for more information about the xtramemsz
parameter and user memory allocation

•

OCIEnvCreate() for a code example illustrating setting N' substitution in a

related function

Regarding OCI_SUPPRESS_NLS_VALIDATION and OCI_ENABLE_NLS_VALIDATION modes, by
default, when client and server character sets are identical, and client and server
releases are both Oracle Database 11g Release 1 (11.1) or later, OCI does not
validate character data in the interest of better performance. This means that if the
application inserts a character string with partial multibyte characters (for example, at
the end of a bind variable), then such strings could get persisted in the database as is.
Note that if either the client or the server release is older than Oracle Database 11g
Release 1 (11.1), then OCI does not allow partial characters.

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The OCI_ENABLE_NLS_VALIDATION mode, which was the default until Oracle Database 10g
Release 2 (10.2), ensures that partial multibyte characters are not persisted in the
database (when client and server character sets are identical). If the application can
produce partial multibyte characters, and if the application can run in an environment
where the client and server character sets are identical, then Oracle recommends
using the OCI_ENABLE_NLS_VALIDATION mode explicitly in order to ensure that such partial
characters get stripped out.
Related Topics
•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIHandleFree()
Explicitly deallocates a handle

•

OCITerminate()
Detaches the process from the shared memory subsystem and releases the
shared memory.

•

OCINlsEnvironmentVariableGet()
Returns the character set ID from NLS_LANG or the national character set ID from
NLS_NCHAR.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

25.2.9 OCILogoff()
Releases a session that was retrieved using OCILogon2() or OCILogon().
Purpose
Releases a session that was retrieved using OCILogon2() or OCILogon().
Syntax
sword OCILogoff ( OCISvcCtx
OCIError

*svchp
*errhp );

Parameters
svchp (IN)
The service context handle that was used in the call to OCILogon() or OCILogon2().
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
This function is used to release a session that was retrieved using OCILogon2() or
OCILogon(). If OCILogon() was used, then this function terminates the connection and
session. If OCILogon2() was used, then the exact behavior of this call is determined by
the mode in which the corresponding OCILogon2() function was called. In the default
case, this function closes the session or connection. For connection pooling, it closes

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the session and returns the connection to the pool. For session pooling, it returns the
session or connection pair to the pool.
Related Topics
•

OCILogon()
Creates a simple logon session.

•

OCILogon2()
Gets a session.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
"Application Initialization, Connection, and Session Creation" for more
information about logging on and off in an application

25.2.10 OCILogon()
Creates a simple logon session.
Purpose
Creates a simple logon session.
Syntax
sword OCILogon ( OCIEnv
*envhp,
OCIError
*errhp,
OCISvcCtx
**svchp,
const OraText *username,
ub4
uname_len,
const OraText *password,
ub4
passwd_len,
const OraText *dbname,
ub4
dbname_len );

Parameters
envhp (IN)
The OCI environment handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
svchp (IN/OUT)
The service context pointer.
username (IN)
The user name. Must be in the encoding specified by the charset parameter of a
previous call to OCIEnvNlsCreate().

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uname_len (IN)
The length of username, in number of bytes, regardless of the encoding.
password (IN)
The user's password. Must be in the encoding specified by the charset parameter of a
previous call to OCIEnvNlsCreate().
passwd_len (IN)
The length of password, in number of bytes, regardless of the encoding.
dbname (IN)
The name of the database to connect to. Must be in the encoding specified by the
charset parameter of a previous call to OCIEnvNlsCreate().
dbname_len (IN)
The length of dbname, in number of bytes, regardless of the encoding.
Comments
This function is used to create a simple logon session for an application.

Note:
Users requiring more complex sessions, such as TP monitor applications,
should see "Application Initialization, Connection, and Session Creation".

This call allocates the service context handles that are passed to it. This call also
implicitly allocates server and user session handles associated with the session.
These handles can be retrieved by calling OCIArrayDescriptorAlloc() on the service
context handle.
Related Topics
•

OCILogoff()
Releases a session that was retrieved using OCILogon2() or OCILogon().

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.11 OCILogon2()
Gets a session.
Purpose
This session may be a new one with a new underlying connection, or one that is
started over a virtual connection from an existing connection pool, or one from an
existing session pool. The mode that the function is called with determines its behavior.

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Syntax
sword OCILogon2 ( OCIEnv
*envhp,
OCIError
*errhp,
OCISvcCtx
**svchp,
const OraText *username,
ub4
uname_len,
const OraText *password,
ub4
passwd_len,
const OraText *dbname,
ub4
dbname_len );
ub4
mode );

Parameters
envhp (IN)
The OCI environment handle. For connection pooling and session pooling, this must
be the one that the respective pool was created in.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
svchp (IN/OUT)
Address of an OCI service context pointer. This is filled with a server and session
handle.
In the default case, a new session and server handle is allocated, the connection and
session are started, and the service context is populated with these handles.
For connection pooling, a new session handle is allocated, and the session is started
over a virtual connection from the connection pool.
For session pooling, the service context is populated with an existing session or
server handle pair from the session pool.
Note that you must not change any attributes of the server and user or session
handles associated with the service context pointer. Doing so results in an error being
returned by the OCIAttrSet() call.
The only attribute of the service context that can be altered is OCI_ATTR_STMTCACHESIZE.
username (IN)
The user name used to authenticate the session. Must be in the encoding specified by
the charset parameter of a previous call to OCIEnvNlsCreate().
uname_len (IN)
The length of username, in number of bytes, regardless of the encoding.
password (IN)
The user's password. For connection pooling, if this parameter is NULL then
OCILogon2() assumes that the logon is for a proxy user. It implicitly creates a proxy
connection in such a case, using the pool user to authenticate the proxy user. Must be
in the encoding specified by the charset parameter of a previous call to
OCIEnvNlsCreate().
passwd_len (IN)
The length of password, in number of bytes, regardless of the encoding.

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dbname (IN)
For the default case, this indicates the connect string to use to connect to the Oracle
Database.
For connection pooling, this indicates the connection pool from which to retrieve the
virtual connection to start the session. This value is returned by the
OCIConnectionPoolCreate() call.
For session pooling, it indicates the pool to get the session from. It is returned by the
OCISessionPoolCreate() call.
The dbname must be in the encoding specified by the charset parameter of a previous
call to OCIEnvNlsCreate().
dbname_len (IN)
The length of dbname. For session pooling and connection pooling, this value is
returned by the OCISessionPoolCreate() or OCIConnectionPoolCreate() call respectively.
mode (IN)
The values accepted are:
•

OCI_DEFAULT

•

OCI_LOGON2_CPOOL

•

OCI_LOGON2_SPOOL

•

OCI_LOGON2_STMTCACHE

•

OCI_LOGON2_PROXY

For the default (nonpooling case), the following modes are valid:
OCI_DEFAULT - Equivalent to calling OCILogon().
OCI_LOGON2_STMTCACHE - Enable statement caching.

For connection pooling, the following modes are valid:
OCI_LOGON2_CPOOL or OCI_CPOOL - This must be set to use connection pooling.
OCI_LOGON2_STMTCACHE - Enable statement caching.

To use proxy authentication for connection pooling, the password must be set to NULL.
You are then given a session that is authenticated by the user name provided in the
OCILogon2() call, through the proxy credentials supplied in the
OCIConnectionPoolCreate() call.
For session pooling, the following modes are valid:
OCI_LOGON2_SPOOL - This must be set to use session pooling.
OCI_LOGON2_STMTCACHE - Enable statement caching.
OCI_LOGON2_PROXY - Use proxy authentication. You are given a session that is
authenticated by the user name provided in the OCILogon2() call, through the proxy
credentials supplied in the OCISessionPoolCreate() call.

Comments
None.

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Related Topics
•

OCILogon()
Creates a simple logon session.

•

OCILogoff()
Releases a session that was retrieved using OCILogon2() or OCILogon().

•

OCISessionGet()
Gets a session.

•

OCISessionRelease()
Releases a session that was retrieved using OCISessionGet().

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIConnectionPoolCreate()
Initializes the connection pool.

•

OCISessionPoolCreate()
Initializes a session pool for use with OCI session pooling and database resident
connection pooling (DRCP).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.12 OCIRequestDisableReplay()
Disables application continuity replay for a session for the duration of the current
database request.
Purpose
Triggers OCI to stop recording calls until the end of an application request (the end of
a request is marked by OCISessionRelease()). Use this call when Application Continuity
for OCI is enabled but the application is entering a section of code that is not
replayable.
Syntax
OCIRequestDisableReplay(OCISvcCtx *svchp,
OCIError *errhp,
ub4
mode);

Parameters
svchp (IN/OUT)
The service context; the service context handle must be initialized and have a session
handle associated with it.
errhp (IN/OUT)
The error handle.
mode (IN)
This call supports the following modes:

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•

OCI_DEFAULT

Usage Notes
See OCI and Application Continuity for more information. See Oracle Real Application
Clusters Administration and Deployment Guide for information about enabling
Application Continuity.

25.2.13 OCIServerAttach()
Creates an access path to a data source for OCI operations.
Purpose
Creates an access path to a data source for OCI operations.
Syntax
sword OCIServerAttach ( OCIServer
OCIError
const OraText
sb4
ub4

*srvhp,
*errhp,
*dblink,
dblink_len,
mode );

Parameters
srvhp (IN/OUT)
An uninitialized server handle, which is initialized by this call. Passing in an initialized
server handle causes an error.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
dblink (IN)
Specifies the database server to use. This parameter points to a character string that
specifies a connect string or a service point. If the connect string is NULL, then this call
attaches to the default host. The string itself could be in UTF-16 encoding mode or not,
depending on the mode or the setting in application's environment handle. The length
of dblink is specified in dblink_len. The dblink pointer may be freed by the caller on
return.
The name of the connection pool to connect to when mode = OCI_CPOOL. This must be
the same as the poolName parameter of the connection pool created by
OCIConnectionPoolCreate(). Must be in the encoding specified by the charset
parameter of a previous call to OCIEnvNlsCreate().
dblink_len (IN)
The length of the string pointed to by dblink. For a valid connect string name or alias,
dblink_len must be nonzero. Its value is in number of bytes.
The length of poolName, in number of bytes, regardless of the encoding, when mode =
OCI_CPOOL.
mode (IN)
Specifies the various modes of operation. The valid modes are:
•

OCI_DEFAULT - For encoding, this value tells the server handle to use the setting in

the environment handle.

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•

OCI_CPOOL - Use connection pooling.

Because an attached server handle can be set for any connection session handle, the
mode value here does not contribute to any session handle.
Comments
This call is used to create an association between an OCI application and a particular
server.
This call assumes that OCIConnectionPoolCreate() has been called, giving poolName,
when connection pooling is in effect.
This call initializes a server context handle, which must have been previously allocated
with a call to OCIHandleAlloc(). The server context handle initialized by this call can be
associated with a service context through a call to OCIAttrSet(). After that association
has been made, OCI operations can be performed against the server.
If an application is operating against multiple servers, multiple server context handles
can be maintained. OCI operations are performed against whichever server context is
currently associated with the service context.
When OCIServerAttach() is successfully completed, an Oracle Database shadow
process is started. OCISessionEnd() and OCIServerDetach() should be called to clean up
the Oracle Database shadow process. Otherwise, the shadow processes accumulate
and cause the Linux or UNIX system to run out of processes. If the database is
restarted and there are not enough processes, the database may not start up.
See OCI and Application Continuity for more information about Application Continuity.
See Oracle Real Application Clusters Administration and Deployment Guide for
information about enabling Application Continuity.
Example
The following code example demonstrates the use of OCIServerAttach(). This code
segment allocates the server handle, makes the attach call, allocates the service
context handle, and then sets the server context into it.
Using the OCIServerAttach() Call
OCIHandleAlloc( (void *) envhp, (void **) &srvhp, (ub4)
OCI_HTYPE_SERVER, 0, (void **) 0);
OCIServerAttach( srvhp, errhp, (text *) 0, (sb4) 0, (ub4) OCI_DEFAULT);
OCIHandleAlloc( (void *) envhp, (void **) &svchp, (ub4)
OCI_HTYPE_SVCCTX, 0, (void **) 0);
/* set attribute server context in the service context */
OCIAttrSet( (void *) svchp, (ub4) OCI_HTYPE_SVCCTX, (void *) srvhp,
(ub4) 0, (ub4) OCI_ATTR_SERVER, (OCIError *) errhp);

Related Topics
•

OCIServerDetach()
Deletes an access path to a data source for OCI operations.

•

OCIConnectionPoolCreate()
Initializes the connection pool.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCISessionEnd()
Terminates a user session context created by OCISessionBegin().

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.14 OCIServerDetach()
Deletes an access path to a data source for OCI operations.
Purpose
Deletes an access path to a data source for OCI operations.
Syntax
sword OCIServerDetach ( OCIServer
OCIError
ub4

*srvhp,
*errhp,
mode );

Parameters
srvhp (IN)
A handle to an initialized server context, which is reset to an uninitialized state. The
handle is not deallocated.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
Specifies the various modes of operation. The only valid mode is OCI_DEFAULT for the
default mode.
Comments
This call deletes an access path a to data source for OCI operations. The access path
was established by a call to OCIServerAttach().
Related Topics
•

OCIServerAttach()
Creates an access path to a data source for OCI operations.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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25.2.15 OCISessionBegin()
Creates a user session and begins a user session for a given server.
Purpose
Creates a user session and begins a user session for a given server.
Syntax
sword OCISessionBegin ( OCISvcCtx
OCIError
OCISession
ub4
ub4

*svchp,
*errhp,
*usrhp,
credt,
mode );

Parameters
svchp (IN)
A handle to a service context. There must be a valid server handle set in svchp.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
usrhp (IN/OUT)
A handle to a user session context, which is initialized by this call.
credt (IN)
Specifies the type of credentials to use for establishing the user session. Valid values
for credt are:
•

OCI_CRED_RDBMS - Authenticate using a database user name and password pair as
credentials. The attributes OCI_ATTR_USERNAME and OCI_ATTR_PASSWORD should be set

on the user session context before this call.
•

OCI_CRED_EXT - Authenticate using external credentials. No user name or password

is provided.
mode (IN)
Specifies the various modes of operation. Valid modes are:
•

OCI_DEFAULT - In this mode, the user session context returned can only ever be set
with the server context specified in svchp. For encoding, the server handle uses

the setting in the environment handle.
•

OCI_MIGRATE - In this mode, the new user session context can be set in a service

handle with a different server handle. This mode establishes the user session
context. To create a migratable session, the service handle must already be set
with a nonmigratable user session, which becomes the "creator" session of the
migratable session. That is, a migratable session must have a nonmigratable
parent session.
OCI_MIGRATE should not be used when the session uses connection pool
underneath. The session migration and multiplexing happens transparently to the
user.

•

OCI_SYSDBA - In this mode, you are authenticated for SYSDBA access.

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•

OCI_SYSOPER - In this mode, you are authenticated for SYSOPER access.

•

OCI_SYSASM - In this mode, you are authenticated for SYSASM access.

•

OCI_SYSBKB - In this mode, you are authenticated for SYSBACKUP access.

•

OCI_SYSDGD - In this mode, you are authenticated for SYSDG access.

•

OCI_SYSKMT - In this mode, you are authenticated for SYSKM access.

•

OCI_SYSRAC - In this mode, you are authenticated for SYSRAC access.

•

OCI_PRELIM_AUTH - This mode can only be used with OCI_SYSDBA or OCI_SYSOPER to

authenticate for certain administration tasks.
•

OCI_STMT_CACHE - Enables statement caching with default size on the given service

handle. It is optional to pass this mode if the application is going to explicitly set
the size later using OCI_ATTR_STMTCACHESIZE on that service handle.
Comments
The OCISessionBegin() call is used to authenticate a user against the server set in the
service context handle.

Note:
Check for any errors returned when trying to start a session. For example, if
the password for the account has expired, an ORA-28001 error is returned.

For release 8.1 or later, OCISessionBegin() must be called for any given server handle
before requests can be made against it. OCISessionBegin() only supports
authenticating the user for access to the Oracle database specified by the server
handle in the service context. In other words, after OCIServerAttach() is called to
initialize a server handle, OCISessionBegin() must be called to authenticate the user for
that given server.
If Application Continuity for OCI is enabled, OCISessionBegin() implicitly marks the
beginning of an application request. When using the OCI session pool APIs, it is not
necessary to call OCIRequestBegin() and OCIRequestEnd().
When using Unicode, when the mode or the environment handle has the appropriate
setting, the user name and password that have been set in the session handle usrhp
should be in Unicode. Before calling this function to start a session with a user name
and password, you must have called OCIAttrSet() to set these two Unicode strings into
the session handle with corresponding length in bytes, because OCIAttrSet() only
takes void pointers. The string buffers then are interpreted by OCISessionBegin().
When OCISessionBegin() is called for the first time for a given server handle, the user
session may not be created in migratable (OCI_MIGRATE) mode.
After OCISessionBegin() has been called for a server handle, the application may call
OCISessionBegin() again to initialize another user session handle with different (or the
same) credentials and different (or the same) operation modes. If an application wants
to authenticate a user in OCI_MIGRATE mode, the service handle must be associated
with a nonmigratable user handle. The user ID of that user handle becomes the
ownership ID of the migratable user session. Every migratable session must have a
nonmigratable parent session.

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If the OCI_MIGRATE mode is not specified, then the user session context can only be
used with the same server handle set in svchp. If the OCI_MIGRATE mode is specified,
then the user authentication can be set with different server handles. However, the
user session context can only be used with server handles that resolve to the same
database instance. Security checking is done during session switching. A session can
migrate to another process only if there is a nonmigratable session currently
connected to that process whose userid is the same as that of the creator's userid or
its own userid.
Do not set the OCI_MIGRATE flag in the call to OCISessionBegin() when the virtual server
handle points to a connection pool (OCIServerAttach() called with mode set to
OCI_CPOOL). Oracle Database supports passing this flag only for compatibility reasons.
Do not use the OCI_MIGRATE flag, as the perception that you get when using a
connection pool is of sessions having their own dedicated (virtual) connections that are
transparently multiplexed onto real connections.
OCI_SYSDBA, OCI_SYSOPER, and OCI_PRELIM_AUTH can only be used with a primary user

session context.
To provide credentials for a call to OCISessionBegin(), two methods are supported. The
first method is to provide a valid user name and password pair for database
authentication in the user session handle passed to OCISessionBegin(). This involves
using OCIAttrSet() to set the OCI_ATTR_USERNAME and OCI_ATTR_PASSWORD attributes on the
user session handle. Then OCISessionBegin() is called with OCI_CRED_RDBMS.

Note:
When the user session handle is terminated using OCISessionEnd(), the user
name and password attributes remain unchanged and thus can be reused in
a future call to OCISessionBegin(). Otherwise, they must be reset to new
values before the next OCISessionBegin() call.

The second method is to use external credentials. No attributes need to be set on the
user session handle before calling OCISessionBegin(). The credential type is
OCI_CRED_EXT. This is equivalent to the Oracle7 'connect /' syntax. If values have been
set for OCI_ATTR_USERNAME and OCI_ATTR_PASSWORD, then these are ignored if OCI_CRED_EXT
is used.
Another way of setting credentials is to use the session ID of an authenticated user
with the OCI_MIGSESSION attribute. This ID can be extracted from the session handle of
an authenticated user using the OCIAttrGet() call.
Example
The following code example demonstrates the use of OCISessionBegin(). This code
segment allocates the user session handle, sets the user name and password
attributes, calls OCISessionBegin(), and then sets the user session into the service
context.
Using the OCISessionBegin() Call
/* allocate a user session handle */
OCIHandleAlloc((void *)envhp, (void **)&usrhp, (ub4)
OCI_HTYPE_SESSION, (size_t) 0, (void **) 0);
OCIAttrSet((void *)usrhp, (ub4)OCI_HTYPE_SESSION, (void *)"hr",

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(ub4)strlen("hr"), OCI_ATTR_USERNAME, errhp);
OCIAttrSet((void *)usrhp, (ub4)OCI_HTYPE_SESSION, (void *)"hr",
(ub4)strlen("hr"), OCI_ATTR_PASSWORD, errhp);
checkerr(errhp, OCISessionBegin (svchp, errhp, usrhp, OCI_CRED_RDBMS,
OCI_DEFAULT));
OCIAttrSet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX, (void *)usrhp,
(ub4)0, OCI_ATTR_SESSION, errhp);

Related Topics
•

OCISessionEnd()
Terminates a user session context created by OCISessionBegin().

•

OCIServerAttach()
Creates an access path to a data source for OCI operations.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIAttrGet()
Gets the value of an attribute of a handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.16 OCISessionEnd()
Terminates a user session context created by OCISessionBegin().
Purpose
Terminates a user session context created by OCISessionBegin().
Syntax
sword OCISessionEnd ( OCISvcCtx
OCIError
OCISession
ub4

*svchp,
*errhp,
*usrhp,
mode );

Parameters
svchp (IN/OUT)
The service context handle. There must be a valid server handle and user session
handle associated with svchp.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
usrhp (IN)
Deauthenticate this user. If this parameter is passed as NULL, the user in the service
context handle is deauthenticated.
mode (IN)
The only valid mode is OCI_DEFAULT.

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Comments
The user security context associated with the service context is invalidated by this call.
Storage for the user session context is not freed. The transaction specified by the
service context is implicitly committed. The transaction handle, if explicitly allocated,
may be freed if it is not being used. Resources allocated on the server for this user are
freed. The user session handle can be reused in a new call to OCISessionBegin().
If Application Continuity for OCI is enabled, OCISessionEnd() implicitly marks the end of
an application request. OCI stops recording calls and purges its call history. When
using the OCI session pool APIs, it is not necessary to call OCIRequestBegin() and
OCIRequestEnd().
Related Topics
•

OCISessionBegin()
Creates a user session and begins a user session for a given server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.17 OCISessionGet()
Gets a session.
Purpose
This session may be a new one with a new underlying connection, or one that is
started over a virtual connection from an existing connection pool, or one from an
existing session pool. The mode that the function is called with determines its behavior.
Syntax
sword OCISessionGet ( OCIenv
OCIError
OCISvcCtx
OCIAuthInfo
OraText
ub4
const OraText
ub4
OraText
ub4
boolean
ub4

*envhp,
*errhp,
**svchp,
*authInfop,
*dbName,
dbName_len,
*tagInfo,
tagInfo_len,
**retTagInfo,
*retTagInfo_len,
*found,
mode );

Parameters
envhp (IN/OUT)
OCI environment handle. For connection pooling and session pooling, the
environment handle in which the respective pool was created.
errhp (IN/OUT)
OCI error handle. Multithreaded OCI clients should pass a unique errhp to the
OCISessionGet() call.

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svchp (OUT)
Address of an OCI service context pointer. This is filled with a server and session
handle.
In the default case, a new session and server handle are allocated, the connection
and session are started, and the service context is populated with these handles.
For connection pooling, a new session handle is allocated, and the session is started
over a virtual connection from the connection pool.
For session pooling, the service context is populated with an existing session and
server handle pair from the session pool.
Do not change any attributes of the server and user and session handles associated
with the service context pointer. Doing so results in an error being returned by the
OCIAttrSet() call.
The only attribute of the service context that can be altered is OCI_ATTR_STMTCACHESIZE.
authInfop (IN)
Authentication information handle to be used while getting the session.
In the default and connection pooling cases, this handle can take all the attributes of
the session handle.
For session pooling, the authentication information handle is considered only if the
session pool mode is not set to OCI_SPC_HOMOGENEOUS. In other words, setting the mode
to OCI_SPC_HOMOGENEOUS, the authentication information is not used, while all other
possible specified attributes are used.
The attributes that can be set on the OCIAuthInfo handle can be categorized into presession-creation attributes and post-session-creation attributes. The pre-sessioncreation attributes are:
Pre-session-creation attributes
Pre-session-creation attributes are those OCI attributes that must be specified before
a session is created. These attributes are used to create a session and cannot be
changed after a session is created. The pre-session creation attributes are:
OCI_ATTR_USERNAME
OCI_ATTR_PASSWORD
OCI_ATTR_CONNECTION_CLASS
OCI_ATTR_PURITY
OCI_ATTR_DISTINGUISHED_NAME
OCI_ATTR_CERTIFICATE
OCI_ATTR_INITIAL_CLIENT_ROLES
OCI_ATTR_APPCTX_SIZE
OCI_ATTR_EDITION
OCI_ATTR_DRIVER_NAME

Post-session-creation attributes
Post-session-creation attributes are those that can be specified after a session is
created. They can be changed freely after a session is created as many times as
desired. The following attributes can be set on the OCISession handle after the session
has been created:
OCI_ATTR_CLIENT_IDENTIFIER
OCI_ATTR_CURRENT_SCHEMA
OCI_ATTR_MODULE
OCI_ATTR_ACTION
OCI_ATTR_DBOP
OCI_ATTR_CLIENT_INFO
OCI_ATTR_COLLECT_CALL_TIME
OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE
OCI_ATTR_SESSION_STATE

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See Also:
•

Session Pooling in OCI

•

cdemosp.c in the demo directory

•

User Session Handle Attributes for more information about the attributes

•

The Comments section

dbName (IN)
For the default case, this indicates the connect string to use to connect to the Oracle
database.
For connection pooling, it indicates the connection pool to retrieve the virtual
connection from, to start the session. This value is returned by the
OCIConnectionPoolCreate() call.
For session pooling, it indicates the pool to get the session from. It is returned by the
OCISessionPoolCreate() call.
dbName_len (IN)
The length of dbName. For session pooling and connection pooling, this value is
returned by the call to OCISessionPoolCreate() or OCIConnectionPoolCreate(),
respectively.
tagInfo (IN)
This parameter is used only for session pooling.
This indicates the type of session that the user wants. If you want a default session,
you must set this to NULL. See the Comments for a detailed explanation of this
parameter.
Beginning with 12c Release 2 (12.2), a tag can have multiple properties. This is
referred to as a multi-property tag. A multi-property tag is comprised of one or more
= pairs separated by a semi-colon, where
= are both strings. See About Using Tags in
Session Pools for more information.
tagInfo_len (IN)
The length, in bytes, of tagInfo. Used for session pooling only.
retTagInfo (OUT)
This parameter is used only for session pooling. This indicates the type of session
that is returned to the user. See the Comments for a detailed explanation of this
parameter.
retTagInfo_len (OUT)
The length, in bytes, of retTagInfo. Used for session pooling only.
found (OUT)
This parameter is used only for session pooling. If the type of session that the user
requested was returned (that is, the value of tagInfo and retTagInfo is the same),
then found is set to TRUE. Otherwise, found is set to FALSE.
mode (IN)
The valid modes are:
•

OCI_DEFAULT

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•

OCI_SESSGET_CPOOL

•

OCI_SESSGET_SPOOL

•

OCI_SESSGET_CREDPROXY

•

OCI_SESSGET_CREDEXT - Supported only for heterogeneous pools.

•

OCI_SESSGET_CUSTOM_POOL

•

OCI_SESSGET_MULTIPROPERTY_TAG

•

OCI_SESSGET_PURITY_NEW

•

OCI_SESSGET_PURITY_SELF

•

OCI_SESSGET_SPOOL_MATCHANY

•

OCI_SESSGET_STMTCACHE

•

OCI_SESSGET_SYSDBA

In the default (nonpooling) case, the following modes are valid:
OCI_SESSGET_STMTCACHE - Enables statement caching in the session.
OCI_SESSGET_CREDEXT - Returns a session authenticated with external credentials.
OCI_SESSGET_SYSDBA - Returns a session with SYSDBA privilege for either nonpooling or for

session pooling.
For connection pooling, the following modes are valid:
OCI_SESSGET_CPOOL - Must be set to use connection pooling.
OCI_SESSGET_STMTCACHE - Enables statement caching in the session.
OCI_SESSGET_CREDPROXY - Returns a proxy session. The user is given a session that is
authenticated by the user name provided in the OCISessionGet() call, through the proxy
credentials supplied in the OCIConnectionPoolCreate() call.
OCI_SESSGET_CREDEXT - Returns a session authenticated with external credentials.

For session pooling, the following modes are valid:
OCI_SESSGET_SPOOL - Must be set to use session pooling.
OCI_SESSGET_SYSDBA - Returns a session with SYSDBA privilege for either nonpooling or for

session pooling.
OCI_SESSGET_CREDEXT - Returns a session authenticated with external credentials.
OCI_SESSGET_CREDPROXY - In this case, the user is given a session that is authenticated
by the user name provided in the OCISessionGet() call, through the proxy credentials
supplied in the OCISessionPoolCreate() call.
OCI_SESSGET_SPOOL_MATCHANY - Refers to the tagging behavior. If this mode is set, then a

session that has a different tag than what was asked for, may be returned. See the
Comments section.
OCI_SESSGET_MULTIPROPERTY_TAG - Must be set when using multiple properties in case

applications previously used a (;) semi-colon character was in a tag name; the semicolon character is used as a separator for specifying multiple properties. See the
Comments section.
For database resident connection pooling, the following modes are valid:

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OCI_SESSGET_MULTIPROPERTY_TAG - Must be set when using multiple properties in case
applications used a (;) semi-colon character was in a tag name; the semi-colon
character is used as a separator for specifying multiple properties. See the Comments
section.
OCI_SESSGET_PURITY_SELF - The application can use a session that has been used

before. You can also specify application-specific tags.
OCI_SESSGET_PURITY_NEW - The application requires a new session that is not tainted with

any prior session state. This is the default.
For custom pools, the following modes are valid:
OCI_SESSGET_CUSTOM_POOL - Must be set by applications that are not using OCI session
pool, but instead are using custom pools. This attribute is set to support shard key
lookup in custom pools.

Comments
The tags provide a way for users to customize sessions in the pool. A client can get a
default or untagged session from a pool, set certain attributes on the session (such as
globalization settings), and return the session to the pool, labeling it with an
appropriate tag in the OCISessionRelease() call.
The user, or some other user, can request a session with the same attributes, and can
do so by providing the same tag in the OCISessionGet() call.
If a user asks for a session with tag 'A', and a matching session is not available, an
appropriately authenticated untagged session (session with a NULL tag) is returned, if
such a session is free. If even an untagged session is not free and
OCI_SESSGET_SPOOL_MATCHANY has been specified, then an appropriately authenticated
session with a different tag is returned. If OCI_SESSGET_SPOOL_MATCHANY is not set, then a
session with a different tag is never returned.
The following code example demonstrates the use of OCI_ATTR_MODULE with session
pooling.
Using the OCI_ATTR_MODULE Attribute with OCI Session Pooling
Oratext *module = (Oratext*) "mymodule";
/* Allocate the pool handle */
checkerr(errhp,OCIHandleAlloc(envhp,(void**)&poolhp,
OCI_HTYPE_SPOOL,0,0));
checkerr(errhp,OCISessionPoolCreate(envhp,
errhp,poolhp,&poolname,&pnamelen,
(oratext*)conn_str,
len,min,max,incr,0,0,0,0,OCI_DEFAULT));
/* Allocate the auth handle for session get */
checkerr(errhp, OCIHandleAlloc(envhp,
(void**)&authp, OCI_HTYPE_AUTHINFO, 0,0));
checkerr(errhp,OCIAttrSet(authp, OCI_HTYPE_AUTHINFO,
username, strlen((char*)username), OCI_ATTR_USERNAME,errhp);
checkerr(errhp,OCIAttrSet(authp, OCI_HTYPE_AUTHINFO,
password, strlen((char*)password), OCI_ATTR_PASSWORD,
errhp));
checkerr(errhp,OCISessionGet(envhp,errhp,

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&svchp,authp,poolname, pnamelen,0,0,0,0,0,
OCI_SESSGET_SPOOL));
/* Get the user handle from the service context handle */
checkerr(errhp, OCIAttrGet(svhcp, OCI_HTYPE_SVCCTX, &usrhp_svc,
0,OCI_ATTR_SESSION,errhp));
/* Set module name on the user handle that you obtained */
checkerr (errhp, OCIAttrSet(usrhp_svc, OCI_HTYPE_SESSION, module,
strlen((char*)module), OCI_ATTR_MODULE,errhp));
/* Make Database calls. */

Restrictions on Attributes Supported for OCI Session Pools
You can use the following pre-session-creation attributes with OCI session pools:
OCI_ATTR_EDITION
OCI_ATTR_DRIVER_NAME
OCI_ATTR_USERNAME,
OCI_ATTR_PASSWORD,
OCI_ATTR_CONNECTION_CLASS,
OCI_ATTR_PURITY

However, OCI_ATTR_EDITION and OCI_ATTR_DRIVERNAME can only be specified during
OCISessionPoolCreate() by setting them on the OCIAuthInfo handle that is an attribute of
OCISPool handle. They cannot be specified on the OCIAuthInfo handle passed into
individual OCISessionGet() calls. This ensures that all sessions that are part of an OCI
session pool have uniform values for these attributes.
The following code example shows how to use the OCI_ATTR_EDITION attribute with an
OCI session pool.
Using the OCI_ATTR_EDITION Attribute with OCI Session Pooling
/* allocate the auth handle to be set on the spool handle */
checkerr(errhp, OCIHandleAlloc(envhp,(void**)&authp_sp,
OCI_HTYPE_AUTHINFO, 0,0));
/* Set the edition on the auth handle */
checkerr(errhp,OCIAttrSet(authp_sp, OCI_HTYPE_AUTHINFO,
"Patch_Bug_12345", strlen("Patch_Bug_12345"),
OCI_ATTR_EDITION,errhp));
/* Allocate the pool handle */
checkerr(errhp,OCIHandleAlloc(envhp,(void**)&poolhp,
OCI_HTYPE_SPOOL,0,0));
/* Set the auth handle created above on the spool handle */
checkerr(errhp,OCIAttrSet(poolhp, OCI_HTYPE_SPOOL,authp_sp,
0,OCI_ATTR_SPOOL_AUTH,errhp));
checkerr(errhp,OCISessionPoolCreate(envhp,
errhp,poolhp,&poolname,&pnamelen,
(oratext*)conn_str,
len,min,max,incr,0,0,0,0,OCI_DEFAULT));
/* Allocate the auth handle for session get */
checkerr(errhp, OCIHandleAlloc(envhp,
(void**)&authp_sessget, OCI_HTYPE_AUTHINFO, 0,0));
checkerr(errhp,OCIAttrSet(authp_sessget, OCI_HTYPE_AUTHINFO,

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username, strlen((char*)username), OCI_ATTR_USERNAME,errhp);
checkerr(errhp,OCIAttrSet(authp_sessget, OCI_HTYPE_AUTHINFO,
password, strlen((char*)password), OCI_ATTR_PASSWORD,
errhp));
checkerr(errhp,OCISessionGet(envhp,errhp,
&svchp,authp_sessget,poolname, pnamelen,0,0,0,0,0,
OCI_SESSGET_SPOOL));

You can use all post-session-creation attributes with OCI session pool. However, as a
session pool can age out sessions, reuse preexisting sessions in the pool, or re-create
new sessions transparently, Oracle recommends that the application explicitly set any
post-session-creation attributes that it needs after getting a session from a pool. This
ensures that the application logic works irrespective of the specific session returned by
the OCI session pool.
When you specify the OCI_SESSGET_MULTIPROPERTY_TAG, the parameter retTagInfo needs
to be interpreted in conjunction with the found parameter and the mode parameter
values specified during OCISessionGet(). The following table specifies these semantics:
Specified Modes

refTagInfo Parameter

found Parameter

OCI_SESSGET_SPOOL |
OCI_SESSGET_MULTIPROPERTY_T
AG

All the properties set on the
found session are returned as
one composite string
delimited by (;) semi-colon.

TRUE, only if the found
session matches all
requested properties and the
session has no additional
properties set.
FALSE, if no matching
session was found. In this
case, a new session, with no
properties set, is returned.

OCI_SESSGET_SPOOL |
OCI_SESSGET_MULTIPROPERTY_T
AG |
OCISESSGET_SPOOL_MATCHANY

All the properties set on the
found session are returned as
one composite string
delimited by (;) semi-colon.

TRUE, if the found session
matches all requested
properties (but may have
additional properties).
FALSE, if the found session
did not match at least one
property.

There is a difference in the manner in which retTagInfo is returned in the case of multiproperty tags as compared to non multi-property tags. In a non multi-property tag
scenario,retTagInfo will be the same as the requested tag when the found parameter is
returned as TRUE. Whereas in the case of a multi-property tag, the retTagInfo contains
the complete set of properties associated with the returned session and further
information should be deduced by the application from the found flag as shown in the
previous table.
Note that OCI_SESSGET_MULTIPROPERTY_TAG (with OCISessionGet()) or
OCI_SESSRLS_MULTIPROPERTY_TAG (with OCISessionRelease()) are only supported with OCI
Session Pool (with or without DRCP). Thus, these modes cannot be used with
standalone connections or with OCI Connection Pool.
Related Topics
•

OCISessionRelease()
Releases a session that was retrieved using OCISessionGet().

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•

OCISessionPoolCreate()
Initializes a session pool for use with OCI session pooling and database resident
connection pooling (DRCP).

•

OCISessionPoolDestroy()
Destroys a session pool.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIConnectionPoolCreate()
Initializes the connection pool.

25.2.18 OCISessionPoolCreate()
Initializes a session pool for use with OCI session pooling and database resident
connection pooling (DRCP).
Purpose
It starts sessMin number of sessions and connections to the database. Before making
this call, make a call to OCIHandleAlloc() to allocate memory for the session pool
handle.
Syntax
sword OCISessionPoolCreate ( OCIEnv
OCIError
OCISPool
OraText
ub4
const OraText
ub4
ub4
ub4
ub4
OraText
ub4
OraText
ub4
ub4

*envhp,
*errhp,
*spoolhp,
**poolName,
*poolNameLen,
*connStr,
connStrLen,
sessMin,
sessMax,
sessIncr,
*userid,
useridLen,
*password,
passwordLen,
mode );

Parameters
envhp (IN)
A pointer to the environment handle in which the session pool is to be created.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet().
spoolhp (IN/OUT)
A pointer to the session pool handle that is initialized.
poolName (OUT)
The name of the session pool returned. It is unique across all session pools in an
environment. This value must be passed to the OCISessionGet() call.

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poolNameLen (OUT)
Length of poolName in bytes.
connStr (IN)
The TNS alias of the database to connect to.
connStrLen (IN)
The length of connStr in bytes.
sessMin (IN)
Specifies the minimum number of sessions in the session pool.
This number of sessions are started by OCISessionPoolCreate(). After the sessions are
started, sessions are opened only when necessary.
This value is used when mode is set to OCI_SPC_HOMOGENEOUS. Otherwise, it is ignored.
sessMax (IN)
Specifies the maximum number of sessions that can be opened in the session pool.
After this value is reached, no more sessions are opened. The valid values are 1 and
higher.
sessIncr (IN)
Allows applications to set the next increment for sessions to be started if the current
number of sessions is less than sessMax. The valid values are 0 and higher.
userid (IN)
Specifies the userid with which to start the sessions.

See Also:
Authentication Note in the Comments Section.
useridLen (IN)
Length of the userid in bytes.
password (IN)
The password for the corresponding userid.
passwordLen (IN)
The length of the password in bytes.
mode (IN)
The modes supported are:
•

OCI_DEFAULT - For a new session pool creation.

•

OCI_SPC_REINITIALIZE - After creating a session pool, if you want to change the
pool attributes dynamically (change the sessMin, sessMax, and sessIncr
parameters), call OCISessionPoolCreate() with mode set to OCI_SPC_REINITIALIZE.
When mode is set to OCI_SPC_REINITIALIZE, then connStr, userid, and password are

ignored.
•

OCI_SPC_STMTCACHE - An OCI statement cache is created for the session pool. If the

pool is not created with OCI statement caching turned on, server-side statement
caching is automatically used. Note that in general, client-side statement caching
gives better performance.

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See Also:
Statement Caching in OCI
•

OCI_SPC_HOMOGENEOUS - All sessions in the pool are authenticated with the user
name and password passed to OCISessionPoolCreate(). The authentication handle
(parameter authInfop) passed into OCISessionGet() is ignored in this case.
Moreover, the sessMin and the SessIncr values are considered only in this case. No
proxy session can be created in this mode. This mode can be used in database
resident connection pooling (DRCP).

•

OCI_SPC_NO_RLB - By default, the runtime connection load balancing is enabled in

the session pool if the client and the server are capable of supporting it. To turn it
off, use the new mode, OCI_SPC_NO_RLB mode of OCISessionPoolCreate(). You can
only use this mode at the time of pool creation. If this mode is passed for a pool
that has been created, an error, ORA-24411, is thrown.
Comments
Authentication Note
A session pool can contain two types of connections to the database: direct
connections and proxy connections. To make a proxy connection, a user must have
Connect through Proxy privilege.

See Also:
For more information about proxy connections, see
•

Client Access Through a Proxy

•

Oracle Database SQL Language Reference

When the session pool is created, the userid and password may or may not be
specified. If these values are NULL, no proxy connections can exist in this pool. If mode
is set to OCI_SPC_HOMOGENEOUS, no proxy connection can exist.
A userid and password pair may also be specified through the authentication handle in
the OCISessionGet() call. If this call is made with mode set to OCI_SESSGET_CREDPROXY,
then the user is given a session that is authenticated by the userid provided in the
OCISessionGet() call, through the proxy credentials supplied in the
OCISessionPoolCreate() call. In this case, the password in the OCISessionGet() call is
ignored.
If OCISessionGet() is called with mode not set to OCI_SESSGET_CREDPROXY, then the user
gets a direct session that is authenticated by the credentials provided in the
OCISessionGet() call. If none have been provided in this call, the user gets a session
authenticated by the credentials in the OCISessionPoolCreate() call.
Example
The following code example shows how to disable runtime load balancing.
Disabling Runtime Load Balancing
OCISessionPoolCreate(envhp, errhp, spoolhp, (OraText **)&poolName,
(ub4 *)&poolNameLen,

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database, (ub4) strlen ((const signed char *) database),
sessMin, sessMax, sessIncr, (OraText *) appusername,
(ub4) strlen ((const signed char *) appusername),
(OraText *) apppassword,
(ub4) strlen ((const signed char *) apppassword),
OCI_SPC_HOMOGENEOUS | OCI_SPC_NO_RLB);

Related Topics
•

OCISessionRelease()
Releases a session that was retrieved using OCISessionGet().

•

OCISessionGet()
Gets a session.

•

OCISessionPoolDestroy()
Destroys a session pool.

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.2.19 OCISessionPoolDestroy()
Destroys a session pool.
Purpose
Destroys a session pool.
Syntax
sword OCISessionPoolDestroy ( OCISPool
OCIError
ub4

*spoolhp,
*errhp,
mode );

spoolhp (IN/OUT)
The session pool handle for the session pool to be destroyed.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet().
mode (IN)
Currently, OCISessionPoolDestroy() supports modes OCI_DEFAULT and OCI_SPD_FORCE.
If this call is made with mode set to OCI_SPD_FORCE, and there are active sessions in the
pool, the sessions are closed and the pool is destroyed. However, if this mode is not
set, and there are busy sessions in the pool, an error is returned.
Related Topics
•

OCISessionPoolCreate()
Initializes a session pool for use with OCI session pooling and database resident
connection pooling (DRCP).

•

OCISessionRelease()
Releases a session that was retrieved using OCISessionGet().

•

OCISessionGet()
Gets a session.

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25.2.20 OCISessionRelease()
Releases a session that was retrieved using OCISessionGet().
Purpose
Releases a session that was retrieved using OCISessionGet(). The exact behavior of
this call is determined by the mode in which the corresponding OCISessionGet() function
was called. In the default case, it closes the session or connection. For connection
pooling, it closes the session and returns the connection to the pool. For session
pooling, it returns the session or connection pair to the pool, and any pending
transaction is committed.
Syntax
sword OCISessionRelease ( OCISvcCtx
OCIError
OraText
ub4
ub4

*svchp,
*errhp,
*tag,
tag_len,
mode );

Parameters
svchp (IN)
The service context that was populated during the corresponding OCISessionGet() call.
In the default case, the session and connection associated with this handle is closed.
In the connection pooling case, the session is closed and the connection released to
the pool.
For session pooling, the session or connection pair associated with this service
context is released to the pool.
errhp (IN/OUT)
The OCI error handle.
tag (IN)
This parameter is used only for session pooling.
This parameter is ignored unless mode OCI_SESSRLS_RETAG is specified. In this case,
the session is labeled with this tag and returned to the pool. If this is NULL, then the
session is not tagged.
tag_len (IN)
This parameter is used only for session pooling.
Length of the tag. This is ignored unless mode OCI_SESSRLS_RETAG is set.
mode (IN)
The supported modes are:
•

OCI_DEFAULT

•

OCI_SESSRLS_DROPSESS

•

OCI_SESSRLS_MULTIPROPERTY_TAG

•

OCI_SESSRLS_RETAG

You can only use OCI_DEFAULT for the default case and for connection pooling.
OCI_SESSRLS_DROPSESS and OCI_SESSRLS_RETAG are only used for session pooling.

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When OCI_SESSRLS_DROPSESS is specified, the session is removed from the session pool.
Set OCI_SESSRLS_MULTIPROPERTY_TAG, if the tag is a multi-property tag. For more
information, see Multi-Property Tags.
The tag on the session is altered if and only if OCI_SESSRLS_RETAG is set. If this mode is
not set, the tag and tag_len parameters are ignored.
Comments
Be careful to pass in the correct tag when using the tag parameter. If a default session
is requested and the user sets certain properties on this session (probably through an
ALTER SESSION command), then the user must label this session appropriately by
tagging it as such.
If, however, the user requested a tagged session and got one, and has changed the
properties on the session, then the user must pass in a different tag if appropriate.
For the correct working of the session pool layer, the application developer must be
very careful to pass in the correct tag to the OCISessionGet() and OCISessionRelease()
calls.
Related Topics
•

OCISessionGet()
Gets a session.

•

OCISessionPoolCreate()
Initializes a session pool for use with OCI session pooling and database resident
connection pooling (DRCP).

•

OCISessionPoolDestroy()
Destroys a session pool.

•

OCILogon2()
Gets a session.

25.2.21 OCITerminate()
Detaches the process from the shared memory subsystem and releases the shared
memory.
Purpose
Detaches the process from the shared memory subsystem and releases the shared
memory.
Syntax
sword OCITerminate ( ub4

mode);

Parameters
mode (IN)
Call-specific mode. Valid value:
•

OCI_DEFAULT - Executes the default call.

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Comments
OCITerminate() should be called only once for each process and is the counterpart of
the OCIEnvCreate(), OCIEnvNlsCreate(), deprecated OCIInitialize() calls. The call tries

to detach the process from the shared memory subsystem and shut it down. It also
performs additional process cleanup operations. When two or more processes
connecting to the same shared memory call OCITerminate() simultaneously, the fastest
one releases the shared memory subsystem completely and the slower ones must
terminate.
Related Topics
•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

25.3 Handle and Descriptor Functions
Lists and describes the OCI handle and descriptor functions.
Table 25-3 lists the OCI handle and descriptor functions that are described in this
section.
Table 25-3

Handle and Descriptor Functions

Function

Purpose

OCIArrayDescriptorAlloc()

Allocate an array of descriptors

OCIArrayDescriptorFree()

Free an array of descriptors

OCIAttrGet()

Get the value of an attribute of a handle

OCIAttrSet()

Set the value of an attribute of a handle or
descriptor

OCIDescriptorAlloc()

Allocate and initialize a descriptor or LOB locator

OCIDescriptorFree()

Free a previously allocated descriptor

OCIHandleAlloc()

Allocate and initialize a handle

OCIHandleFree()

Free a previously allocated handle

OCIParamGet()

Get a parameter descriptor

OCIParamSet()

Set parameter descriptor in COR handle

25.3.1 OCIArrayDescriptorAlloc()
Allocates an array of descriptors.
Purpose
Allocates an array of descriptors.

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Syntax
sword OCIArrayDescriptorAlloc ( const void
*parenth,
void
**descpp,
const ub4
type,
ub4
array_size,
const size_t xtramem_sz,
void
**usrmempp);

Parameters
parenth (IN)
An environment handle.
descpp (OUT)
Returns a pointer to a contiguous array of descriptors of the desired type.
type (IN)
Specifies the type of descriptor or LOB locator to be allocated. For a list of types, see
OCIDescriptorAlloc().
array_size (IN)
Specifies the number of descriptors to allocate. An error is thrown when the call
cannot allocate the number of descriptors.
xtramem_sz (IN)
Specifies an amount of user memory to be allocated for use by the application for the
lifetime of the descriptors.
usrmempp (OUT)
Returns a pointer to an array of pointers numbering in array_size, since there is one
chunk allocated for each of the descriptors allocated.
Comments
This call returns OCI_SUCCESS if successful, or a suitable error if an out-of-memory
condition occurs.

See Also:
User Memory Allocation for more information about the xtramem_sz parameter
and user memory allocation

Example
The following code example can be modified to allocate a large number of descriptors.
Allocating a Large Number of Descriptors
OCIDateTime *descpp1[500];
...
for (i = 0; i!=500; i++)
{
/* Allocate descriptors */
OCIDescriptorAlloc((void *)envhp,(void **)&descpp1[i], OCI_DTYPE_TIMESTAMP_TZ,

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0,(void **)0);
}
...

The for loop in the previous code example can now be replaced with a single call, as
shown in the following code example.
Allocating an Array of Descriptors
OCIArrayDescriptorAlloc((void *)envhp,(void **)&descpp1,
OCI_DTYPE_TIMESTAMP_TZ, 500, 0, (void **)0);

Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCIArrayDescriptorFree()
Free a previously allocated array of descriptors.

25.3.2 OCIArrayDescriptorFree()
Free a previously allocated array of descriptors.
Purpose
Free a previously allocated array of descriptors.
Syntax
sword OCIArrayDescriptorFree ( void
const ub4

**descp,
type );

Parameters
descp (IN)
Pointer to an array of allocated descriptors.
type (IN)
Specifies the type of storage to be freed. See the types listed in OCIDescriptorAlloc().
Comments
An error is returned when a descriptor is allocated using OCIDescriptorAlloc(), but
freed using OCIArrayDescriptorFree().
If you perform LOB operations, you must always call OCILobFreeTemporary() before
calling OCIArrayDescriptorFree() to free the contents of the temporary LOB. See About
Freeing Temporary LOBs for more information.
Descriptors allocated using OCIArrayDescriptorAlloc() must be freed using
OCIArrayDescriptorFree(). You must be careful to free the entire array at once: pass in
the pointer descpp returned by OCIArrayDescriptorAlloc() to OCIArrayDescriptorFree()
appropriately. Otherwise, there can be memory leaks.
Related Topics
•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

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•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

25.3.3 OCIAttrGet()
Gets the value of an attribute of a handle.
Purpose
Gets the value of an attribute of a handle.
Syntax
sword OCIAttrGet ( const void
ub4
void
ub4
ub4
OCIError

*trgthndlp,
trghndltyp,
*attributep,
*sizep,
attrtype,
*errhp );

Parameters
trgthndlp (IN)
Pointer to a handle type. The actual handle can be a statement handle, a session
handle, and so on. When this call is used to get encoding, users are allowed to check
against either an environment or statement handle.
trghndltyp (IN)
The handle type. Valid types are:
•

OCI_DTYPE_PARAM, for a parameter descriptor

•

OCI_HTYPE_STMT, for a statement handle

•

Any handle type in Table 4-1 or any descriptor in Table 4-2.

attributep (OUT)
Pointer to the storage for an attribute value. Is in the encoding specified by the
charset parameter of a previous call to OCIEnvNlsCreate().
sizep (OUT)
The size of the attribute value, always in bytes because attributep is a void pointer.
This can be passed as NULL for most attributes because the sizes of non-string
attributes are already known by the OCI library. For text* parameters, a pointer to a
ub4 must be passed in to get the length of the string.
attrtype (IN)
The type of attribute being retrieved. The handle types and their readable attributes
are listed in Handle and Descriptor Attributes.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
This call is used to get a particular attribute of a handle. OCI_DTYPE_PARAM is used to do
implicit and explicit describes. The parameter descriptor is also used in direct path

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loading. For implicit describes, the parameter descriptor has the column description for
each select list. For explicit describes, the parameter descriptor has the describe
information for each schema object that you are trying to describe. If the top-level
parameter descriptor has an attribute that is itself a descriptor, use OCI_ATTR_PARAM as
the attribute type in the subsequent call to OCIAttrGet() to get the Unicode information
in an environment or statement handle.

See Also:
Examples Using OCIDescribeAny() and About Describing Select-List Items

A function closely related to OCIAttrGet() is OCIDescribeAny(), which is a generic
describe call that describes existing schema objects: tables, views, synonyms,
procedures, functions, packages, sequences, and types. As a result of this call, the
describe handle is populated with the object-specific attributes that can be obtained
through an OCIAttrGet() call.
Then an OCIParamGet() call on the describe handle returns a parameter descriptor for a
specified position. Parameter positions begin with 1. Calling OCIAttrGet() on the
parameter descriptor returns the specific attributes of a stored procedure or function
parameter or a table column descriptor. These subsequent calls do not need an extra
round-trip to the server because the entire schema object description is cached on the
client side by OCIDescribeAny(). Calling OCIAttrGet() on the describe handle can also
return the total number of positions.
In UTF-16 mode, particularly when executing a loop, try to reuse the same pointer
variable corresponding to an attribute and copy the contents to local variables after
OCIAttrGet() is called. If multiple pointers are used for the same attribute, a memory
leak can occur.
Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIDescribeAny()
Describes existing schema and subschema objects.

•

OCIParamGet()
Returns a descriptor of a parameter specified by position in the describe handle or
statement handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.3.4 OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.
Purpose
Sets the value of an attribute of a handle or a descriptor.

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Syntax
sword OCIAttrSet ( void
ub4
void
ub4
ub4
OCIError

*trgthndlp,
trghndltyp,
*attributep,
size,
attrtype,
*errhp );

Parameters
trgthndlp (IN/OUT)
Pointer to a handle whose attribute gets modified.
trghndltyp (IN/OUT)
The handle type.
attributep (IN)
Pointer to an attribute value. The attribute value is copied into the target handle. If the
attribute value is a pointer, then only the pointer is copied, not the contents of the
pointer. String attributes must be in the encoding specified by the charset parameter
of a previous call to OCIEnvNlsCreate().
size (IN)
The size of an attribute value. This can be passed in as 0 for most attributes, as the
size is already known by the OCI library. For text* attributes, a ub4 must be passed in
set to the length of the string in bytes, regardless of encoding.
attrtype (IN)
The type of attribute being set.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
See Handle and Descriptor Attributes for a list of handle types and their writable
attributes.
Related Topics
•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.3.5 OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.
Purpose
Allocates storage to hold descriptors or LOB locators.

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Syntax
sword OCIDescriptorAlloc ( const void
void
ub4
size_t
void

*parenth,
**descpp,
type,
xtramem_sz,
**usrmempp);

Parameters
parenth (IN)
An environment handle.
descpp (OUT)
Returns a descriptor or LOB locator of the desired type.
type (IN)
Specifies the type of descriptor or LOB locator to be allocated:
•

OCI_DTYPE_SNAP - Specifies generation of snapshot descriptor of C type OCISnapshot.

•

OCI_DTYPE_LOB - Specifies generation of a LOB value type locator (for a BLOB or
CLOB) of C type OCILobLocator.

•

OCI_DTYPE_FILE - Specifies generation of a FILE value type locator of C type
OCILobLocator.

•

OCI_DTYPE_ROWID - Specifies generation of a ROWID descriptor of C type OCIRowid.

•

OCI_DTYPE_DATE - Specifies generation of an ANSI DATE descriptor of C type
OCIDateTime.

•

OCI_DTYPE_PARAM - Specifies generation of a read-only parameter descriptor of C
type OCIParam.

•

OCI_DTYPE_TIMESTAMP - Specifies generation of a TIMESTAMP descriptor of C type
OCIDateTime.

•

OCI_DTYPE_TIMESTAMP_TZ - Specifies generation of a TIMESTAMP WITH TIME ZONE
descriptor of C type OCIDateTime.

•

OCI_DTYPE_TIMESTAMP_LTZ - Specifies generation of a TIMESTAMP WITH LOCAL TIME ZONE
descriptor of C type OCIDateTime.

•

OCI_DTYPE_INTERVAL_YM - Specifies generation of an INTERVAL YEAR TO MONTH
descriptor of C type OCIInterval.

•

OCI_DTYPE_INTERVAL_DS - Specifies generation of an INTERVAL DAY TO SECOND
descriptor of C type OCIInterval.

•

OCI_DTYPE_COMPLEXOBJECTCOMP - Specifies generation of a complex object retrieval
descriptor of C type OCIComplexObjectComp.

•

OCI_DTYPE_AQENQ_OPTIONS - Specifies generation of an Advanced Queuing enqueue
options descriptor of C type OCIAQEnqOptions.

•

OCI_DTYPE_AQDEQ_OPTIONS - Specifies generation of an Advanced Queuing dequeue
options descriptor of C type OCIAQDeqOptions.

•

OCI_DTYPE_AQMSG_PROPERTIES - Specifies generation of an Advanced Queuing
message properties descriptor of C type OCIAQMsgProperties.

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•

OCI_DTYPE_AQAGENT - Specifies generation of an Advanced Queuing agent descriptor
of C type OCIAQAgent.

•

OCI_DTYPE_AQNFY - Specifies generation of an Advanced Queuing notification
descriptor of C type OCIAQNotify.

•

OCI_DTYPE_AQLIS_OPTIONS - Specifies generation of an Advanced Queuing listen
descriptor of C type OCIAQListenOpts.

•

OCI_DTYPE_AQLIS_MSG_PROPERTIES - Specifies generation of an Advanced Queuing
message properties descriptor of C type OCIAQLisMsgProps.

•

OCI_DTYPE_SHARDING_KEY - Specifies generation of the shard key or the shard group
key of C type OCIShardingKey.

•

OCI_DTYPE_SRVDN - Specifies generation of a Distinguished Names descriptor of C
type OCIServerDNs.

•

OCI_DTYPE_UCB - Specifies generation of a user callback descriptor of C type OCIUcb.

xtramem_sz (IN)
Specifies an amount of user memory to be allocated for use by the application for the
lifetime of the descriptor.
usrmempp (OUT)
Returns a pointer to the user memory of size xtramem_sz allocated by the call for the
user for the lifetime of the descriptor.
Comments
Returns a pointer to an allocated and initialized descriptor, corresponding to the type
specified in type. A non-NULL descriptor or LOB locator is returned on success. No
diagnostics are available on error.
This call returns OCI_SUCCESS if successful, or OCI_INVALID_HANDLE if an out-of-memory
error occurs.
Related Topics
•

OCIDescriptorFree()
Deallocates a previously allocated descriptor.

•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIArrayDescriptorFree()
Free a previously allocated array of descriptors.

See Also:
User Memory Allocation for more information about the xtramem_sz parameter
and user memory allocation

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25.3.6 OCIDescriptorFree()
Deallocates a previously allocated descriptor.
Purpose
Deallocates a previously allocated descriptor.
Syntax
sword OCIDescriptorFree ( void
ub4

*descp,
type );

Parameters
descp (IN)
An allocated descriptor.
type (IN)
Specifies the type of storage to be freed. See the types listed in OCIDescriptorAlloc().
Comments
This call frees storage associated with a descriptor. Returns OCI_SUCCESS or
OCI_INVALID_HANDLE. All descriptors can be explicitly deallocated; however, OCI
deallocates a descriptor if the environment handle is deallocated.
If you perform LOB operations, you must always call OCILobFreeTemporary() before
calling OCIDescriptorFree() to free the contents of the temporary LOB. See About
Freeing Temporary LOBs for more information.
Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

25.3.7 OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.
Purpose
Returns a pointer to an allocated and initialized handle.
Syntax
sword OCIHandleAlloc ( const void
void
ub4
size_t
void

*parenth,
**hndlpp,
type,
xtramem_sz,
**usrmempp );

Parameters
parenth (IN)
An environment handle.

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hndlpp (OUT)
Returns a handle.
type (IN)
Specifies the type of handle to be allocated. The allowed handles are described in
Table 4-1.
xtramem_sz (IN)
Specifies an amount of user memory to be allocated.
usrmempp (OUT)
Returns a pointer to the user memory of size xtramem_sz allocated by the call for the
user.
Comments
Returns a pointer to an allocated and initialized handle, corresponding to the type
specified in type. A non-NULL handle is returned on success. All handles are allocated
with respect to an environment handle that is passed in as a parent handle.
No diagnostics are available on error. This call returns OCI_SUCCESS if successful, or
OCI_INVALID_HANDLE if an error occurs.
Handles must be allocated using OCIHandleAlloc() before they can be passed into an
OCI call.
Related Topics
•

OCIHandleFree()
Explicitly deallocates a handle

See Also:
User Memory Allocation for more information about using the xtramem_sz
parameter for user memory allocation

25.3.8 OCIHandleFree()
Explicitly deallocates a handle
Purpose
This call explicitly deallocates a handle.
Syntax
sword OCIHandleFree ( void
ub4

*hndlp,
type );

Parameters
hndlp (IN)
A handle allocated by OCIHandleAlloc().

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type (IN)
Specifies the type of storage to be freed. The handles are described in Table 4-1.
Comments
This call frees up storage associated with a handle, corresponding to the type
specified in the type parameter.
This call returns either OCI_SUCCESS, OCI_INVALID_HANDLE, or OCI_ERROR.
All handles may be explicitly deallocated. The OCI deallocates a child handle if the
parent is deallocated.
When a statement handle is freed, the cursor associated with the statement handle is
closed, but the actual cursor closing may be deferred to the next round-trip to the
server. If the application must close the cursor immediately, you can make a server
round-trip call, such as OCIServerVersion() or OCIPing(), after the OCIHandleFree() call.
Related Topics
•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIServerVersion()
Returns the Oracle Database version string.

•

OCIPing()
Confirms that the connection and the server are active.

25.3.9 OCIParamGet()
Returns a descriptor of a parameter specified by position in the describe handle or
statement handle.
Purpose
Returns a descriptor of a parameter specified by position in the describe handle or
statement handle.
Syntax
sword OCIParamGet ( const void
ub4
OCIError
void
ub4

*hndlp,
htype,
*errhp,
**parmdpp,
pos );

Parameters
hndlp (IN)
A statement handle or describe handle. The OCIParamGet() function returns a
parameter descriptor for this handle.
htype (IN)
The type of the handle passed in the hndlp parameter. Valid types are:
•

OCI_DTYPE_PARAM, for a parameter descriptor

•

OCI_HTYPE_COMPLEXOBJECT, for a complex object retrieval handle

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•

OCI_HTYPE_STMT, for a statement handle

errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
parmdpp (OUT)
A descriptor of the parameter at the position given in the pos parameter, of handle
type OCI_DTYPE_PARAM.
pos (IN)
Position number in the statement handle or describe handle. A parameter descriptor
is returned for this position.

Note:
OCI_ERROR is returned if there are no parameter descriptors for this position.

Comments
This call returns a descriptor of a parameter specified by position in the describe
handle or statement handle. Parameter descriptors are always allocated internally by
the OCI library. They can be freed using OCIDescriptorFree(). For example, if you fetch
the same column metadata for every execution of a statement, then the program leaks
memory unless you explicitly free the parameter descriptor between each call to
OCIParamGet().
Related Topics
•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIParamSet()
Sets a complex object retrieval (COR) descriptor into a COR handle.

•

OCIDescriptorFree()
Deallocates a previously allocated descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Handle and Descriptor Attributes for more detailed information about
parameter descriptor attributes

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25.3.10 OCIParamSet()
Sets a complex object retrieval (COR) descriptor into a COR handle.
Purpose
Sets a complex object retrieval (COR) descriptor into a COR handle.
Syntax
sword OCIParamSet ( void
ub4
OCIError
const void
ub4
ub4

*hndlp,
htype,
*errhp,
*dscp,
dtyp,
pos );

Parameters
hndlp (IN/OUT)
Handle pointer.
htype (IN)
Handle type.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
dscp (IN)
Complex object retrieval descriptor pointer.
dtyp (IN)
Descriptor type. The descriptor type for a COR descriptor is
OCI_DTYPE_COMPLEXOBJECTCOMP.
pos (IN)
Position number.
Comments
The COR handle must have been previously allocated using OCIHandleAlloc(), and the
descriptor must have been previously allocated using OCIDescriptorAlloc(). Attributes
of the descriptor are set using OCIAttrSet().
Related Topics
•

OCIParamGet()
Returns a descriptor of a parameter specified by position in the describe handle or
statement handle.

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

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•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Complex Object Retrieval for more information about complex object retrieval

25.4 Bind, Define, and Describe Functions
Lists and describes the bind, define, and describe functions.
Table 25-4 lists the bind, define, and describe functions that are described in this
section.
Table 25-4

Bind, Define, and Describe Functions

Function

Purpose

OCIBindArrayOfStruct()

Set skip parameters for static array bind

OCIBindByName()

Bind by name

OCIBindByName2()

Bind by name. Use when return lengths
exceed UB2MAXVAL on the client.

OCIBindByPos()

Bind by position

OCIBindByPos2()

Bind by position. Use when return lengths
exceed UB2MAXVAL on the client.

OCIBindDynamic()

Set additional attributes after bind with
OCI_DATA_AT_EXEC mode

OCIBindObject()

Set additional attributes for bind of named
data type

OCIDefineArrayOfStruct()

Set additional attributes for static array define

OCIDefineByPos()

Define an output variable association

OCIDefineByPos2()

Define an output variable association. Use
when return lengths exceed UB2MAXVAL on
the client.

OCIDefineDynamic()

Set additional attributes for define in
OCI_DYNAMIC_FETCH mode

OCIDefineObject()

Set additional attributes for define of named
data type

OCIDescribeAny()

Describe existing schema objects

OCIStmtGetBindInfo()

Get bind and indicator variable names and
handle

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25.4.1 OCIBindArrayOfStruct()
Sets up the skip parameters for a static array bind.
Purpose
Sets up the skip parameters for a static array bind.
Syntax
sword OCIBindArrayOfStruct ( OCIBind
OCIError
ub4
ub4
ub4
ub4

*bindp,
*errhp,
pvskip,
indskip,
alskip,
rcskip );

Parameters
bindp (IN/OUT)
The handle to a bind structure.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
pvskip (IN)
Skip parameter for the next data value.
indskip (IN)
Skip parameter for the next indicator value or structure.
alskip (IN)
Skip parameter for the next actual length value.
rcskip (IN)
Skip parameter for the next column-level return code value.
Comments
This call sets up the skip parameters necessary for a static array bind. It follows a call
to OCIBindByName() or OCIBindByPos(). The bind handle returned by that initial bind call
is used as a parameter for the OCIBindArrayOfStruct() call.
Related Topics
•

OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.

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•

OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

See Also:
About Binding and Defining Arrays of Structures in OCI for information about
skip parameters

25.4.2 OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.
Purpose
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.
Syntax
sword OCIBindByName ( OCIStmt
*stmtp,
OCIBind
**bindpp,
OCIError
*errhp,
const OraText *placeholder,
sb4
placeh_len,
void
*valuep,
sb4
value_sz,
ub2
dty,
void
*indp,
ub2
*alenp,
ub2
*rcodep,
ub4
maxarr_len,
ub4
*curelep,
ub4
mode );

Parameters
stmtp (IN/OUT)
The statement handle to the SQL or PL/SQL statement being processed.
bindpp (IN/OUT)
A pointer to save the pointer of a bind handle that is implicitly allocated by this call.
The bind handle maintains all the bind information for this particular input value. The
default encoding for the call depends on the UTF-16 setting in stmtp unless the mode
parameter has a different value. The handle is freed implicitly when the statement
handle is deallocated. On input, the value of the pointer must be NULL or a valid bind
handle.

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errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
placeholder (IN)
The placeholder, specified by its name, that maps to a variable in the statement
associated with the statement handle. The encoding of placeholder should always be
consistent with that of the environment. That is, if the statement is prepared in UTF-16,
so is the placeholder. As a string type parameter, the placeholder should be cast as
(text *) and terminated with NULL.
placeh_len (IN)
The length of the name specified in placeholder, in number of bytes regardless of the
encoding.
valuep (IN/OUT)
The pointer to a data value or an array of data values of type specified in the dty
parameter. This data could be a UTF-16 (formerly known as UCS-2) string, if an
OCIAttrSet() function has been called to set OCI_ATTR_CHARSET_ID as OCI_UTF16ID or the
deprecated OCI_UCS2ID. OCI_UTF16ID is the new designation for OCI_UCS2ID.
Furthermore, as pointed out for OCIStmtPrepare2() , the default encoding for the string
type valuep is in the encoding specified by the charset parameter of a previous call to
OCIEnvNlsCreate(), unless you call OCIAttrSet() to manually reset the character set for
the bind handle.

See Also:
Bind Handle Attributes
An array of data values can be specified for mapping into a PL/SQL table or for
providing data for SQL multiple-row operations. When an array of bind values is
provided, this is called an array bind in OCI terms.
For SQLT_NTY or SQLT_REF binds, the valuep parameter is ignored. The pointers to OUT
buffers are set in the pgvpp parameter initialized by OCIBindObject().
When mode is set to OCI_IOV, pass the base address of the OCIIOV struct.
value_sz (IN)
The maximum size possible in bytes of any data value (passed using valuep) for this
bind variable. This size is always expected to be the size in bytes. In the case of an
array bind, this is the maximum size of any element possible with the actual sizes
being specified in the alenp parameter.
For descriptors, locators, or REFs, whose size is unknown to client applications, use
the size of the pointer to the specific type; for example, sizeof (OCILobLocator *).
The same applies even when mode is OCI_IOV.
dty (IN)
The data type of the values being bound. Named data types (SQLT_NTY) and REFs
(SQLT_REF) are valid only if the application has been initialized in object mode. For
named data types or REFs, additional calls must be made with the bind handle to set
up the data type-specific attributes. See Comments for information about records,
collections, and Booleans. For named data type SQLT_CHR, OCIBindByName() trims

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trailing blanks when the actual length is 0. Specify the actual length to prevent trailing
blanks from being trimmed.
indp (IN/OUT)
Pointer to an indicator variable or array. For all data types except SQLT_NTY, this is a
pointer to sb2 or an array of sb2.
For SQLT_NTY, this pointer is ignored, and the actual pointer to the indicator structure or
an array of indicator structures is initialized in a subsequent call to OCIBindObject().
This parameter is ignored for dynamic binds.

See Also:
Indicator Variables
alenp (IN/OUT)
Pointer to the array of actual lengths of array elements.
When OCIEnvNlsCreate() (which is the recommended OCI environment handle
creation interface) is used, then alenp lengths are consistently expected in bytes (for
IN binds) and reported in bytes for OUT binds. The same treatment consistently also
holds for the length prefix in SQLT_VCS (2-byte length prefix) and SQLT_LVC (4-byte length
prefix) types. There are no special exceptions for UCS2 or for NCHAR cases.
When the older OCI environment handle creation interfaces are used (either
OCIEnvCreate()) or deprecated OCIEnvInit()), alenp lengths are in bytes in general.
However, alenp lengths are expected in characters for IN binds and also reported in
characters for OUT binds only when either the character set is OCI_UC2ID (=
OCI_UTF16ID) or when OCI_ATTR_CHAR_COUNT attribute is set on the corresponding
OCIBind handle. The same treatment holds for the length prefix in SQLT_VCS (2-byte
length prefix) and SQLT_LVC (4-byte length prefix) types.
This parameter is ignored for dynamic binds.
rcodep (OUT)
Pointer to the array of column-level return codes. This parameter is ignored for
dynamic binds.
maxarr_len (IN)
A maximum array length parameter (the maximum possible number of elements the
user's array can accommodate). Used only for PL/SQL indexed table bindings.
curelep (IN/OUT)
Current array length parameter (a pointer to the actual number of elements in the
array before or after the execute operation). Used only for PL/SQL indexed table
bindings.
mode (IN)
To maintain coding consistency, theoretically this parameter can take all three
possible values used by OCIStmtPrepare2(). Because the encoding of bind variables
should always be same as that of the statement containing this variable, an error is
raised if you specify an encoding other than that of the statement. So the
recommended setting for mode is OCI_DEFAULT, which makes the bind variable have the
same encoding as its statement.
The valid modes are:
•

OCI_DEFAULT - The default mode. The statement handle that stmtp uses whatever is

specified by its parent environment handle.

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•

OCI_BIND_SOFT - Soft bind mode. This mode increases the performance of the call.
If this is the first bind or some input value like dty or value_sz is changed from the

previous bind, this mode is ignored. An error is returned if the statement is not
executed. Unexpected behavior results if the bind handle passed is not valid.
•

OCI_DATA_AT_EXEC - When this mode is selected, the value_sz parameter defines the

maximum size of the data that can be provided at run time. The application must
be ready to provide the OCI library runtime IN data buffers at any time and any
number of times. Runtime data is provided in one of these two ways:
–

Callbacks using a user-defined function that must be registered with a
subsequent call to OCIBindDynamic().

–

A polling mechanism using calls supplied by the OCI. This mode is assumed if
no callbacks are defined.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about using the OCI_DATA_AT_EXEC mode
When mode is set to OCI_DATA_AT_EXEC, do not provide values for valuep, indp, alenp,
and rcodep in the main call. Pass zeros (0) for indp and alenp. Provide the values
through the callback function registered using OCIBindDynamic().
•

OCI_IOV - Bind noncontiguous addresses of data. The valuep parameter must be of
the type OCIIOV *. This mode is intended to be used for scatter or gather binding,

which allows multiple buffers to be bound or defined to a position, for example
column A for the first 10 rows in one buffer, next 5 rows in one buffer, and the
remaining 25 rows in another buffer. That eliminates the need to allocate and copy
all of them into one big buffer while doing the array execute operation.

See Also:
About Binding and Defining Multiple Buffers
When the allocated buffers are not required anymore, they should be freed by the
client.
Comments
This call is used to perform a basic bind operation. The bind creates an association
between the address of a program variable and a placeholder in a SQL statement or
PL/SQL block. The bind call also specifies the type of data that is being bound, and
may also indicate the method by which data is provided at run time.
Encoding is determined by either the bind handle using the setting in the statement
handle as default, or you can override the setting by specifying the mode parameter
explicitly.
The OCIBindByName() and OCIBimdByName2() also implicitly allocates the bind handle
indicated by the bindpp parameter. If a non-NULL pointer is passed in **bindpp, the OCI
assumes that this points to a valid handle that has been previously allocated with a call
to OCIHandleAlloc() or OCIBindByName().

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Data in an OCI application can be bound to placeholders statically or dynamically.
Binding is static when all the IN bind data and the OUT bind buffers are well defined
just before the execute operation. Binding is dynamic when the IN bind data and the
OUT bind buffers are provided by the application on demand at execution time to the
client library. Dynamic binding is indicated by setting the mode parameter of this call to
OCI_DATA_AT_EXEC.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about dynamic binding

Both OCIBindByName() and OCIBindByName2() and OCIBindByPos() and OCIBindByPos2()
take as a parameter a bind handle, which is implicitly allocated by the bind call. A
separate bind handle is allocated for each placeholder the application is binding.
Additional bind calls may be required to specify particular attributes necessary when
binding certain data types or handling input data in certain ways:
•

If arrays of structures are being used, OCIBindArrayOfStruct() must be called to set
up the necessary skip parameters.

•

If data is being provided dynamically at run time, and the application uses userdefined callback functions, OCIBindDynamic() must be called to register the
callbacks.

•

If lengths in alenp greater than 64 Kilobytes (KB) are required, use
OCIBindDynamic().

•

If a named data type is being bound, OCIBindObject() must be called to specify
additional necessary information.

•

If a statement with the RETURNING clause is used, a call to OCIBindDynamic() must
follow this call.

With IN binds, the values for each element of the array, the actual lengths of each
element, and the actual array length must be set up before the call to
OCIStmtExecute().
With OUT binds, the values for each element of the array, the actual lengths of each
element, and the actual array length are returned from the server after the
OCIStmtExecute() call.
For Records
Clients must bind package record types using SQLT_NTY as the DTY of the bind. In the
OCI client, objects and records are represented as Named Types (NTY) and must use
the same SQLT code.
For Collections
Clients must bind all package collection types using SQLT_NTY. This is the DTY used to
bind all schema level collection types.
For Booleans
Clients must bind Boolean types (OCI_TYPECODE_BOOLEAN) using SQLT_BOL.

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Related Topics
•

OCIBindDynamic()
Registers user callbacks for dynamic data allocation.

•

OCIBindObject()
Sets up additional attributes that are required for a named data type (object) bind.

•

OCIBindArrayOfStruct()
Sets up the skip parameters for a static array bind.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.3 OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.
Purpose
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call instead of OCIBindByName() when working with
data types when actual lengths exceed UB2MAXVAL on the client.
Syntax
sword OCIBindByName2 ( OCIStmt
OCIBind

*stmtp,
**bindpp,

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OCIError
const OraText
sb4
void
sb8
ub2
void
ub4
ub2
ub4
ub4
ub4

*errhp,
*placeholder,
placeh_len,
*valuep,
value_sz,
dty,
*indp,
*alenp,
*rcodep,
maxarr_len,
*curelep,
mode );

Parameters
stmtp (IN/OUT)
The statement handle to the SQL or PL/SQL statement being processed.
bindpp (IN/OUT)
A pointer to save the pointer of a bind handle that is implicitly allocated by this call.
The bind handle maintains all the bind information for this particular input value. The
default encoding for the call depends on the UTF-16 setting in stmtp unless the mode
parameter has a different value. The handle is freed implicitly when the statement
handle is deallocated. On input, the value of the pointer must be NULL or a valid bind
handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
placeholder (IN)
The placeholder, specified by its name, that maps to a variable in the statement
associated with the statement handle. The encoding of placeholder should always be
consistent with that of the environment. That is, if the statement is prepared in UTF-16,
so is the placeholder. As a string type parameter, the placeholder should be cast as
(text *) and terminated with NULL.
placeh_len (IN)
The length of the name specified in placeholder, in number of bytes regardless of the
encoding.
valuep (IN/OUT)
The pointer to a data value or an array of data values of type specified in the dty
parameter. This data could be a UTF-16 (formerly known as UCS-2) string, if an
OCIAttrSet() function has been called to set OCI_ATTR_CHARSET_ID as OCI_UTF16ID or the
deprecated OCI_UCS2ID. OCI_UTF16ID is the new designation for OCI_UCS2ID.
Furthermore, as pointed out for OCIStmtPrepare2(), the default encoding for the string
type valuep is in the encoding specified by the charset parameter of a previous call to
OCIEnvNlsCreate(), unless you call OCIAttrSet() to manually reset the character set for
the bind handle.

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See Also:
Bind Handle Attributes
An array of data values can be specified for mapping into a PL/SQL table or for
providing data for SQL multiple-row operations. When an array of bind values is
provided, this is called an array bind in OCI terms.
For SQLT_NTY or SQLT_REF binds, the valuep parameter is ignored. The pointers to OUT
buffers are set in the pgvpp parameter initialized by OCIBindObject().
When mode is set to OCI_IOV, pass the base address of the OCIIOV struct.
value_sz (IN)
The maximum size possible in bytes of any data value (passed using valuep) for this
bind variable. This size is always expected to be the size in bytes. In the case of an
array bind, this is the maximum size of any element possible with the actual sizes
being specified in the alenp parameter.
If the value of value_sz > SB4MAXVAL, an ORA-24452 error will be issued, meaning that
values > SB4MAXVAL are not supported in Release 12.1 or later.
For descriptors, locators, or REFs, whose size is unknown to client applications, use
the size of the pointer to the specific type; for example, sizeof (OCILobLocator *).
The same applies even when mode is OCI_IOV.
dty (IN)
The data type of the values being bound. Named data types (SQLT_NTY) and REFs
(SQLT_REF) are valid only if the application has been initialized in object mode. For
named data types or REFs, additional calls must be made with the bind handle to set
up the data type-specific attributes. See Comments for information about records,
collections, and Booleans. For named data type SQLT_CHR, OCIBindByName2() trims
trailing blanks when the actual length is 0. Specify the actual length to prevent trailing
blanks from being trimmed.
indp (IN/OUT)
Pointer to an indicator variable or array. For all data types except SQLT_NTY, this is a
pointer to sb2 or an array of sb2.
For SQLT_NTY, this pointer is ignored, and the actual pointer to the indicator structure or
an array of indicator structures is initialized in a subsequent call to OCIBindObject().
This parameter is ignored for dynamic binds.

See Also:
Indicator Variables
alenp (IN/OUT)
Pointer to the array of actual lengths of array elements.
When OCIEnvNlsCreate() (which is the recommended OCI environment handle
creation interface) is used, then alenp lengths are consistently expected in bytes (for
IN binds) and reported in bytes for OUT binds. The same treatment consistently also
holds for the length prefix in SQLT_VCS (2-byte length prefix) and SQLT_LVC (4-byte length
prefix) types. There are no special exceptions for UCS2 or for NCHAR cases.

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When the older OCI environment handle creation interfaces are used (either
OCIEnvCreate()) or deprecated OCIEnvInit()), alenp lengths are in bytes in general.
However, alenp lengths are expected in characters for IN binds and also reported in

characters for OUT binds only when either the character set is OCI_UC2ID (=
OCI_UTF16ID) or when OCI_ATTR_CHAR_COUNT attribute is set on the corresponding
OCIBind handle. The same treatment holds for the length prefix in SQLT_VCS (2-byte
length prefix) and SQLT_LVC (4-byte length prefix) types.
This parameter is ignored for dynamic binds.
rcodep (OUT)
Pointer to the array of column-level return codes. This parameter is ignored for
dynamic binds.
maxarr_len (IN)
A maximum array length parameter (the maximum possible number of elements the
user's array can accommodate). Used only for PL/SQL indexed table bindings.
curelep (IN/OUT)
Current array length parameter (a pointer to the actual number of elements in the
array before or after the execute operation). Used only for PL/SQL indexed table
bindings.
mode (IN)
To maintain coding consistency, theoretically this parameter can take all three
possible values used by OCIStmtPrepare2(). Because the encoding of bind variables
should always be same as that of the statement containing this variable, an error is
raised if you specify an encoding other than that of the statement. So the
recommended setting for mode is OCI_DEFAULT, which makes the bind variable have the
same encoding as its statement.
The valid modes are:
•

OCI_DEFAULT - The default mode. The statement handle that stmtp uses whatever is

specified by its parent environment handle.
•

OCI_BIND_SOFT - Soft bind mode. This mode increases the performance of the call.
If this is the first bind or some input value like dty or value_sz is changed from the

previous bind, this mode is ignored. An error is returned if the statement is not
executed. Unexpected behavior results if the bind handle passed is not valid.
•

OCI_DATA_AT_EXEC - When this mode is selected, the value_sz parameter defines the

maximum size of the data that can be provided at run time. The application must
be ready to provide the OCI library runtime IN data buffers at any time and any
number of times. Runtime data is provided in one of these two ways:
–

Callbacks using a user-defined function that must be registered with a
subsequent call to OCIBindDynamic().

–

A polling mechanism using calls supplied by the OCI. This mode is assumed if
no callbacks are defined.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about using the OCI_DATA_AT_EXEC mode

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When mode is set to OCI_DATA_AT_EXEC, do not provide values for valuep, indp, alenp,
and rcodep in the main call. Pass zeros (0) for indp and alenp. Provide the values
through the callback function registered using OCIBindDynamic().
•

OCI_IOV - Bind noncontiguous addresses of data. The valuep parameter must be of
the type OCIIOV *. This mode is intended to be used for scatter or gather binding,

which allows multiple buffers to be bound or defined to a position, for example
column A for the first 10 rows in one buffer, next 5 rows in one buffer, and the
remaining 25 rows in another buffer. That eliminates the need to allocate and copy
all of them into one big buffer while doing the array execute operation.

See Also:
About Binding and Defining Multiple Buffers
When the allocated buffers are not required anymore, they should be freed by the
client.
Comments
This call is used to perform a basic bind operation. The bind creates an association
between the address of a program variable and a placeholder in a SQL statement or
PL/SQL block. The bind call also specifies the type of data that is being bound, and
may also indicate the method by which data is provided at run time.
Encoding is determined by either the bind handle using the setting in the statement
handle as default, or you can override the setting by specifying the mode parameter
explicitly.
The OCIBindByName2() also implicitly allocates the bind handle indicated by the bindpp
parameter. If a non-NULL pointer is passed in **bindpp, the OCI assumes that this
points to a valid handle that has been previously allocated with a call to
OCIHandleAlloc() or OCIBindByName2().
Data in an OCI application can be bound to placeholders statically or dynamically.
Binding is static when all the IN bind data and the OUT bind buffers are well defined
just before the execute operation. Binding is dynamic when the IN bind data and the
OUT bind buffers are provided by the application on demand at execution time to the
client library. Dynamic binding is indicated by setting the mode parameter of this call to
OCI_DATA_AT_EXEC.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about dynamic binding

Both OCIBindByName2() and OCIBindByPos2() take as a parameter a bind handle, which
is implicitly allocated by the bind call. A separate bind handle is allocated for each
placeholder the application is binding.
Additional bind calls may be required to specify particular attributes necessary when
binding certain data types or handling input data in certain ways:

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•

If arrays of structures are being used, OCIBindArrayOfStruct() must be called to set
up the necessary skip parameters.

•

If data is being provided dynamically at run time, and the application uses userdefined callback functions, OCIBindDynamic() must be called to register the
callbacks.

•

If lengths in alenp greater than 64 Kilobytes (KB) are required, use
OCIBindDynamic().

•

If a named data type is being bound, OCIBindObject() must be called to specify
additional necessary information.

•

If a statement with the RETURNING clause is used, a call to OCIBindDynamic() must
follow this call.

With IN binds, the values for each element of the array, the actual lengths of each
element, and the actual array length must be set up before the call to
OCIStmtExecute().
With OUT binds, the values for each element of the array, the actual lengths of each
element, and the actual array length are returned from the server after the
OCIStmtExecute() call.
For Records
Clients must bind package record types using SQLT_NTY as the DTY of the bind. In the
OCI client, objects and records are represented as Named Types (NTY) and must use
the same SQLT code.
For Collections
Clients must bind all package collection types using SQLT_NTY. This is the DTY used to
bind all schema level collection types.
For Booleans
Clients must bind Boolean types (OCI_TYPECODE_BOOLEAN) using SQLT_BOL.
Related Topics
•

OCIBindDynamic()
Registers user callbacks for dynamic data allocation.

•

OCIBindObject()
Sets up additional attributes that are required for a named data type (object) bind.

•

OCIBindArrayOfStruct()
Sets up the skip parameters for a static array bind.

•

OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.4 OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.
Purpose
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.
Syntax
sword OCIBindByPos ( OCIStmt
OCIBind
OCIError
ub4
void
sb4
ub2
void
ub2
ub2
ub4
ub4
ub4

*stmtp,
**bindpp,
*errhp,
position,
*valuep,
value_sz,
dty,
*indp,
*alenp,
*rcodep,
maxarr_len,
*curelep,
mode );

Parameters
stmtp (IN/OUT)
The statement handle to the SQL or PL/SQL statement being processed.
bindpp (IN/OUT)
An address of a bind handle that is implicitly allocated by this call. The bind handle
maintains all the bind information for this particular input value. The handle is freed
implicitly when the statement handle is deallocated. On input, the value of the pointer
must be NULL or a valid bind handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.

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position (IN)
The placeholder attributes are specified by position if OCIBindByPos() is being called.
Positions are 1-based.
valuep (IN/OUT)
An address of a data value or an array of data values of the type specified in the dty
parameter. An array of data values can be specified for mapping into a PL/SQL table
or for providing data for SQL multiple-row operations. When an array of bind values is
provided, this is called an array bind in OCI terms.
For a LOB, the buffer pointer must be a pointer to a LOB locator of type
OCILobLocator. Give the address of the pointer.
For SQLT_NTY or SQLT_REF binds, the valuep parameter is ignored. The pointers to
OUT buffers are set in the pgvpp parameter initialized by OCIBindObject().
If the OCI_ATTR_CHARSET_ID attribute is set to OCI_UTF16ID (replaces the deprecated
OCI_UCS2ID, which is retained for backward compatibility), all data passed to and
received with the corresponding bind call is assumed to be in UTF-16 encoding.
When mode is set to OCI_IOV, pass the base address of the OCIIOV struct.

See Also:
Bind Handle Attributes
value_sz (IN)
The maximum size possible in bytes of any data value (passed using valuep) for this
bind variable. This size is always expected to be the size in bytes. In the case of an
array bind, this is the maximum size of any element possible with the actual sizes
being specified in the alenp parameter.
For descriptors, locators, or REFs, whose size is unknown to client applications, use
the size of the pointer to the specific type; for example, sizeof (OCILobLocator *).
The same applies even when mode is OCI_IOV.
dty (IN)
The data type of the values being bound. Named data types (SQLT_NTY) and REFs
(SQLT_REF) are valid only if the application has been initialized in object mode. For
named data types or REFs, additional calls must be made with the bind handle to set
up the attributes specific to the data type. See Comments for information about
records, collections, and Booleans. For named data type SQLT_CHR, OCIBindByPos()
trims trailing blanks when the actual length is 0. Specify the actual length to prevent
trailing blanks from being trimmed.
indp (IN/OUT)
Pointer to an indicator variable or array. For all data types, this is a pointer to sb2 or an
array of sb2 values. The only exception is SQLT_NTY, where this pointer is ignored
and the actual pointer to the indicator structure or an array of indicator structures is
initialized by OCIBindObject(). The indp parameter is ignored for dynamic binds. If
valuep is an OUT parameter, then you must set indp to point to OCI_IND_NULL.

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See Also:
Indicator Variables
alenp (IN/OUT)
Pointer to an array of actual lengths of array elements.
When OCIEnvNlsCreate() (which is the recommended OCI environment handle
creation interface) is used, then alenp lengths are consistently expected in bytes (for
IN binds) and reported in bytes for OUT binds. The same treatment consistently also
holds for the length prefix in SQLT_VCS (2-byte length prefix) and SQLT_LVC (4-byte length
prefix) types. There are no special exceptions for UCS2 or for NCHAR cases.
When the older OCI environment handle creation interfaces are used (either
OCIEnvCreate() or deprecated OCIEnvInit()), alenp lengths are in bytes in general.
However, alenp lengths are expected in characters for IN binds and also reported in
characters for OUT binds only when either the character set is OCI_UC2ID (=
OCI_UTF16ID) or when OCI_ATTR_CHAR_COUNT attribute is set on the corresponding
OCIBind handle. The same treatment holds for the length prefix in SQLT_VCS (2-byte
length prefix) and SQLT_LVC (4-byte length prefix) types.
This parameter is ignored for dynamic binds.
rcodep (OUT)
Pointer to an array of column-level return codes. This parameter is ignored for
dynamic binds.
maxarr_len (IN)
A maximum array length parameter (the maximum possible number of elements that
the user's array can accommodate). Used only for PL/SQL indexed table bindings.
curelep (IN/OUT)
Current array length parameter (a pointer to the actual number of elements in the
array before or after the execute operation). Used only for PL/SQL indexed table
bindings.
mode (IN)
The valid modes for this parameter are:
•

OCI_DEFAULT - This is default mode.

•

OCI_BIND_SOFT - Soft bind mode. This mode increases the performance of the call.
If this is the first bind or some input value like dty or value_sz is changed from the

previous bind, this mode is ignored. An error is returned if the statement is not
executed. Unexpected behavior results if the bind handle passed is not valid.
•

OCI_DATA_AT_EXEC - When this mode is selected, the value_sz parameter defines

the maximum size of the data that can be provided at run time. The application
must be ready to provide the OCI library runtime IN data buffers at any time and
any number of times. Runtime data is provided in one of the following ways:
–

Callbacks using a user-defined function that must be registered with a
subsequent call to OCIBindDynamic().

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–

A polling mechanism using calls supplied by OCI. This mode is assumed if no
callbacks are defined.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about using the OCI_DATA_AT_EXEC mode

When mode is set to OCI_DATA_AT_EXEC, do not provide values for valuep, indp,
alenp, and rcodep in the main call. Pass zeros (0) for indp and alenp. Provide
the values through the callback function registered using OCIBindDynamic().
•

OCI_IOV - Bind noncontiguous addresses of data. The valuep parameter must be of
the type OCIIOV *. This mode is intended to be used for scatter or gather binding,

which allows multiple buffers to be bound or defined to a position, for example
column A for the first 10 rows in one buffer, next 5 rows in one buffer, and the
remaining 25 rows in another buffer. That eliminates the need to allocate and
copy all of them into one big buffer while doing the array execute operation.

See Also:
About Binding and Defining Multiple Buffers
When the allocated buffers are not required anymore, they should be freed by the
client.
Comments
This call is used to perform a basic bind operation. The bind creates an association
between the address of a program variable and a placeholder in a SQL statement or
PL/SQL block. The bind call also specifies the type of data that is being bound, and
may also indicate the method by which data is to be provided at run time.
This function also implicitly allocates the bind handle indicated by the bindpp
parameter. If a non-NULL pointer is passed in **bindpp, OCI assumes that this points to
a valid handle that has been previously allocated with a call to OCIHandleAlloc() or
OCIBindByPos().
Data in an OCI application can be bound to placeholders statically or dynamically.
Binding is static when all the IN bind data and the OUT bind buffers are well defined
just before the execute operation. Binding is dynamic when the IN bind data and the
OUT bind buffers are provided by the application on demand at execution time to the
client library. Dynamic binding is indicated by setting the mode parameter of this call to
OCI_DATA_AT_EXEC.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about dynamic binding

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Both OCIBindByName() and OCIBindByPos() take as a parameter a bind handle, which is
implicitly allocated by the bind call. A separate bind handle is allocated for each
placeholder the application is binding.
Additional bind calls may be required to specify particular attributes necessary when
binding certain data types or handling input data in certain ways:
•

If arrays of structures are being used, OCIBindArrayOfStruct() must be called to set
up the necessary skip parameters.

•

If data is being provided dynamically at run time, and the application uses userdefined callback functions, OCIBindDynamic() must be called to register the
callbacks.

•

If lengths in alenp greater than 64 KB are required, use OCIBindDynamic().

•

If a named data type is being bound, OCIBindObject() must be called to specify
additional necessary information.

•

If a statement with the RETURNING clause is used, a call to OCIBindDynamic() must
follow this call.

With IN binds, the values for each element of the array, the actual lengths of each
element, and the actual array length must be set up before the call to
OCIStmtExecute().
With OUT binds, the values for each element of the array, the actual lengths of each
element, and the actual array length are returned from the server after
theOCIStmtExecute() call.
For Records
Clients must bind package record types using SQLT_NTY as the DTY of the bind. In the
OCI client, objects and records are represented as Named Types (NTY) and must use
the same SQLT code.
For Collections
Clients must bind all package collection types using SQLT_NTY. This is the DTY used to
bind all schema level collection types.
For Booleans
Clients must bind Boolean types (OCI_TYPECODE_BOOLEAN) using SQLT_BOL.
Related Topics
•

OCIBindDynamic()
Registers user callbacks for dynamic data allocation.

•

OCIBindObject()
Sets up additional attributes that are required for a named data type (object) bind.

•

OCIBindArrayOfStruct()
Sets up the skip parameters for a static array bind.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.5 OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when actual
lengths exceed UB2MAXVAL on the client.
Purpose
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call instead of OCIBindByPos() when working with
data types when actual lengths exceed UB2MAXVAL on the client.
Syntax
sword OCIBindByPos2 ( OCIStmt
OCIBind
OCIError
ub4
void
sb8
ub2
void
ub4
ub2
ub4
ub4
ub4

*stmtp,
**bindpp,
*errhp,
position,
*valuep,
value_sz,
dty,
*indp,
*alenp,
*rcodep,
maxarr_len,
*curelep,
mode );

Parameters
stmtp (IN/OUT)
The statement handle to the SQL or PL/SQL statement being processed.
bindpp (IN/OUT)
An address of a bind handle that is implicitly allocated by this call. The bind handle
maintains all the bind information for this particular input value. The handle is freed
implicitly when the statement handle is deallocated. On input, the value of the pointer
must be NULL or a valid bind handle.

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errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
position (IN)
The placeholder attributes are specified by position if OCIBindByPos() is being called.
Positions are 1-based.
valuep (IN/OUT)
An address of a data value or an array of data values of the type specified in the dty
parameter. An array of data values can be specified for mapping into a PL/SQL table
or for providing data for SQL multiple-row operations. When an array of bind values is
provided, this is called an array bind in OCI terms.
For a LOB, the buffer pointer must be a pointer to a LOB locator of type
OCILobLocator. Give the address of the pointer.
For SQLT_NTY or SQLT_REF binds, the valuep parameter is ignored. The pointers to
OUT buffers are set in the pgvpp parameter initialized by OCIBindObject().
If the OCI_ATTR_CHARSET_ID attribute is set to OCI_UTF16ID (replaces the deprecated
OCI_UCS2ID, which is retained for backward compatibility), all data passed to and
received with the corresponding bind call is assumed to be in UTF-16 encoding.
When mode is set to OCI_IOV, pass the base address of the OCIIOV struct.

See Also:
Bind Handle Attributes
value_sz (IN)
The maximum size possible in bytes of any data value (passed using valuep) for this
bind variable. This size is always expected to be the size in bytes. In the case of an
array bind, this is the maximum size of any element possible with the actual sizes
being specified in the alenp parameter.
If the value of value_sz > SB4MAXVAL, an ORA-24452 error will be issued, meaning that
values > SB4MAXVAL are not supported in Release 12.1 or later.
For descriptors, locators, or REFs, whose size is unknown to client applications, use
the size of the pointer to the specific type; for example, sizeof (OCILobLocator *).
The same applies even when mode is OCI_IOV.
dty (IN)
The data type of the values being bound. Named data types (SQLT_NTY) and REFs
(SQLT_REF) are valid only if the application has been initialized in object mode. For
named data types or REFs, additional calls must be made with the bind handle to set
up the attributes specific to the data type. See Comments for information about
records, collections, and Booleans. For named data type SQLT_CHR, OCIBindByPos2()
trims trailing blanks when the actual length is 0. Specify the actual length to prevent
trailing blanks from being trimmed.
indp (IN/OUT)
Pointer to an indicator variable or array. For all data types, this is a pointer to sb2 or an
array of sb2 values. The only exception is SQLT_NTY, where this pointer is ignored
and the actual pointer to the indicator structure or an array of indicator structures is
initialized by OCIBindObject(). The indp parameter is ignored for dynamic binds. If
valuep is an OUT parameter, then you must set indp to point to OCI_IND_NULL.

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See Also:
Indicator Variables
alenp (IN/OUT)
Pointer to an array of actual lengths of array elements.
When OCIEnvNlsCreate() (which is the recommended OCI environment handle
creation interface) is used, then alenp lengths are consistently expected in bytes (for
IN binds) and reported in bytes for OUT binds. The same treatment consistently also
holds for the length prefix in SQLT_VCS (2-byte length prefix) and SQLT_LVC (4-byte length
prefix) types. There are no special exceptions for UCS2 or for NCHAR cases.
When the older OCI environment handle creation interfaces are used (either
OCIEnvCreate() or deprecated OCIEnvInit()), alenp lengths are in bytes in general.
However, alenp lengths are expected in characters for IN binds and also reported in
characters for OUT binds only when either the character set is OCI_UC2ID (=
OCI_UTF16ID) or when OCI_ATTR_CHAR_COUNT attribute is set on the corresponding
OCIBind handle. The same treatment holds for the length prefix in SQLT_VCS (2-byte
length prefix) and SQLT_LVC (4-byte length prefix) types.
This parameter is ignored for dynamic binds.
rcodep (OUT)
Pointer to an array of column-level return codes. This parameter is ignored for
dynamic binds.
maxarr_len (IN)
A maximum array length parameter (the maximum possible number of elements that
the user's array can accommodate). Used only for PL/SQL indexed table bindings.
curelep (IN/OUT)
Current array length parameter (a pointer to the actual number of elements in the
array before or after the execute operation). Used only for PL/SQL indexed table
bindings.
mode (IN)
The valid modes for this parameter are:
•

OCI_DEFAULT - This is default mode.

•

OCI_BIND_SOFT - Soft bind mode. This mode increases the performance of the call.
If this is the first bind or some input value like dty or value_sz is changed from the

previous bind, this mode is ignored. An error is returned if the statement is not
executed. Unexpected behavior results if the bind handle passed is not valid.
•

OCI_DATA_AT_EXEC - When this mode is selected, the value_sz parameter defines

the maximum size of the data that can be provided at run time. The application
must be ready to provide the OCI library runtime IN data buffers at any time and
any number of times. Runtime data is provided in one of the following ways:
–

Callbacks using a user-defined function that must be registered with a
subsequent call to OCIBindDynamic().

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–

A polling mechanism using calls supplied by OCI. This mode is assumed if no
callbacks are defined.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about using the OCI_DATA_AT_EXEC mode

When mode is set to OCI_DATA_AT_EXEC, do not provide values for valuep, indp,
alenp, and rcodep in the main call. Pass zeros (0) for indp and alenp. Provide
the values through the callback function registered using OCIBindDynamic().
•

OCI_IOV - Bind noncontiguous addresses of data. The valuep parameter must be of
the type OCIIOV * . This mode is intended to be used for scatter or gather binding,

which allows multiple buffers to be bound or defined to a position, for example
column A for the first 10 rows in one buffer, next 5 rows in one buffer, and the
remaining 25 rows in another buffer. That eliminates the need to allocate and
copy all of them into one big buffer while doing the array execute operation.

See Also:
About Binding and Defining Multiple Buffers
When the allocated buffers are not required anymore, they should be freed by the
client.
Comments
This call is used to perform a basic bind operation. The bind creates an association
between the address of a program variable and a placeholder in a SQL statement or
PL/SQL block. The bind call also specifies the type of data that is being bound, and
may also indicate the method by which data is to be provided at run time.
This function also implicitly allocates the bind handle indicated by the bindpp
parameter. If a non-NULL pointer is passed in **bindpp, OCI assumes that this points to
a valid handle that has been previously allocated with a call to OCIHandleAlloc() or
OCIBindByPos2().
Data in an OCI application can be bound to placeholders statically or dynamically.
Binding is static when all the IN bind data and the OUT bind buffers are well defined
just before the execute operation. Binding is dynamic when the IN bind data and the
OUT bind buffers are provided by the application on demand at execution time to the
client library. Dynamic binding is indicated by setting the mode parameter of this call to
OCI_DATA_AT_EXEC.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about dynamic binding

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Both OCIBindByName2() and OCIBindByPos2() take as a parameter a bind handle, which
is implicitly allocated by the bind call. A separate bind handle is allocated for each
placeholder the application is binding.
Additional bind calls may be required to specify particular attributes necessary when
binding certain data types or handling input data in certain ways:
•

If arrays of structures are being used, OCIBindArrayOfStruct() must be called to set
up the necessary skip parameters.

•

If data is being provided dynamically at run time, and the application uses userdefined callback functions, OCIBindDynamic() must be called to register the
callbacks.

•

If lengths in alenp greater than 64 KB are required, use OCIBindDynamic().

•

If a named data type is being bound, OCIBindObject() must be called to specify
additional necessary information.

•

If a statement with the RETURNING clause is used, a call to OCIBindDynamic() must
follow this call.

With IN binds, the values for each element of the array, the actual lengths of each
element, and the actual array length must be set up before the call to
OCIStmtExecute() .
With OUT binds, the values for each element of the array, the actual lengths of each
element, and the actual array length are returned from the server after the
OCIStmtExecute() call.
For Records
Clients must bind package record types using SQLT_NTY as the DTY of the bind. In the
OCI client, objects and records are represented as Named Types (NTY) and must use
the same SQLT code.
For Collections
Clients must bind all package collection types using SQLT_NTY. This is the DTY used to
bind all schema level collection types.
For Booleans
Clients must bind Boolean types (OCI_TYPECODE_BOOLEAN) using SQLT_BOL.
Related Topics
•

OCIBindDynamic()
Registers user callbacks for dynamic data allocation.

•

OCIBindObject()
Sets up additional attributes that are required for a named data type (object) bind.

•

OCIBindArrayOfStruct()
Sets up the skip parameters for a static array bind.

•

OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.6 OCIBindDynamic()
Registers user callbacks for dynamic data allocation.
Purpose
Registers user callbacks for dynamic data allocation.
Syntax
sword OCIBindDynamic ( OCIBind
*bindp,
OCIError
*errhp,
void
*ictxp,
OCICallbackInBind
void
OCIBind
ub4
ub4
void
ub4
ub1
void
void
OCICallbackOutBind
void
OCIBind
ub4
ub4
void
ub4
ub1
void
ub2

(icbfp)(
*ictxp,
*bindp,
iter,
index,
**bufpp,
*alenp,
*piecep,
**indpp ),
*octxp,
(ocbfp)(
*octxp,
*bindp,
iter,
index,
**bufpp,
**alenpp,
*piecep,
**indpp,
**rcodepp ) );

Parameters
bindp (IN/OUT)
A bind handle returned by a call to OCIBindByName() or OCIBindByPos().

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errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
ictxp (IN)
The context pointer required by the callback function icbfp.
icbfp (IN)
The callback function that returns a pointer to the IN bind value or piece at run time.
The callback takes in the following parameters:
ictxp (IN/OUT)
The context pointer for this callback function.
bindp (IN)
The bind handle passed in to uniquely identify this bind variable.
iter (IN)
A 0-based execute iteration value.
index (IN)
Index of the current array, for an array bind in PL/SQL. For SQL it is the row index.
The value is 0-based and not greater than the curelep parameter of the bind call.
bufpp (OUT)
The pointer to the buffer or storage. For descriptors, *bufpp contains a pointer to the
descriptor. For example, if you define the following parameter, then you set *bufpp to
lobp, not *lobp.
OCILobLocator

*lobp;

For REFs, pass the address of the ref; that is, pass &my_ref for *bufpp.
If the OCI_ATTR_CHARSET_ID attribute is set to OCI_UTF16ID (replaces the deprecated
OCI_UCS2ID, which is retained for backward compatibility), all data passed to and
received with the corresponding bind call is assumed to be in UTF-16 encoding.

See Also:
Bind Handle Attributes
alenp (OUT)
A pointer to storage for OCI to fill in the size of the bind value or piece after it has
been read. For descriptors, pass the size of the pointer to the descriptor; for example,
sizeof(OCILobLocator *).
piecep (OUT)
A piece of the bind value. This can be one of the following values: OCI_ONE_PIECE,
OCI_FIRST_PIECE, OCI_NEXT_PIECE, and OCI_LAST_PIECE. For data types that do not
support piecewise operations, you must pass OCI_ONE_PIECE or an error is generated.
indpp (OUT)
Contains the indicator value. This is either a pointer to an sb2 value or a pointer to an
indicator structure for binding named data types.

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octxp (IN)
The context pointer required by the callback function ocbfp().
ocbfp (IN)
The callback function that returns a pointer to the OUT bind value or piece at run time.
The callback takes in the following parameters:
octxp (IN/OUT)
The context pointer for this callback function.
bindp (IN)
The bind handle passed in to uniquely identify this bind variable.
iter (IN)
A 0-based execute iteration value.
index (IN)
For PL/SQL, the index of the current array for an array bind. For SQL, the index is the
row number in the current iteration. It is 0-based, and must not be greater than the
curelep parameter of the bind call.
bufpp (OUT)
A pointer to a buffer to write the bind value or piece in.
If the OCI_ATTR_CHARSET_ID attribute is set to OCI_UTF16ID (replaces the deprecated
OCI_UCS2ID, which is retained for backward compatibility), all data passed to and
received with the corresponding bind call is assumed to be in UTF-16 encoding. For
more information, see "Bind Handle Attributes".
alenpp (IN/OUT)
A pointer to storage for OCI to fill in the size of the bind value or piece after it has
been read. It is in bytes except for Unicode encoding (if the OCI_ATTR_CHARSET_ID
attribute is set to OCI_UTF16ID), when it is in code points.
piecep (IN/OUT)
Returns a piece value from the callback (application) to the Oracle Database, as
follows:
•

IN - The value can be OCI_ONE_PIECE or OCI_NEXT_PIECE.

•

OUT - Depends on the IN value:

–

If IN value is OCI_ONE_PIECE, then OUT value can be OCI_ONE_PIECE or
OCI_FIRST_PIECE.

–

If IN value is OCI_NEXT_PIECE, then OUT value can be OCI_NEXT_PIECE or
OCI_LAST_PIECE.

indpp (OUT)
Contains the indicator value. This is either a pointer to an sb2 value, or a pointer to an
indicator structure for binding named data types.
rcodepp (OUT)
Returns a pointer to the return code.
Comments
This call is used to register user-defined callback functions for providing or receiving
data if OCI_DATA_AT_EXEC mode was specified in a previous call to OCIBindByName() or
OCIBindByPos().

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The callback function pointers must return OCI_CONTINUE if the call is successful. Any
return code other than OCI_CONTINUE signals that the client wants to terminate
processing immediately.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about the OCI_DATA_AT_EXEC mode

When passing the address of a storage area, ensure that the storage area exists even
after the application returns from the callback. This means that you should not allocate
such storage on the stack.

Note:
After you use OCIEnvNlsCreate() to create the environment handle, the actual
lengths and returned lengths of bind and define handles are always in
number of bytes.

Related Topics
•

OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.7 OCIBindObject()
Sets up additional attributes that are required for a named data type (object) bind.
Purpose
Sets up additional attributes that are required for a named data type (object) bind.

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Syntax
sword OCIBindObject ( OCIBind
OCIError
const OCIType
void
ub4
void
ub4

*bindp,
*errhp,
*type,
**pgvpp,
*pvszsp,
**indpp,
*indszp, );

Parameters
bindp (IN/OUT)
The bind handle returned by the call to OCIBindByName() or OCIBindByName2() or
OCIBindByPos() or OCIBindByPos2().
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
type (IN)
Points to the TDO that describes the type of program variable being bound. Retrieved
by calling OCITypeByName(). Optional for REFs in SQL, but required for REFs in PL/SQL.
pgvpp (IN/OUT)
Address of the program variable buffer. For an array, pgvpp points to an array of
addresses. When the bind variable is also an OUT variable, the OUT named data
type value or REF is allocated in the Object Cache, and a REF is returned.
pgvpp is ignored if the OCI_DATA_AT_EXEC mode is set. Then the named data type buffers
are requested at run time. For static array binds, skip factors may be specified using
the OCIBindArrayOfStruct() call. The skip factors are used to compute the address of
the next pointer to the value, the indicator structure, and their sizes.
pvszsp (OUT) [optional]
Points to the size of the program variable. The size of the named data type is not
required on input. For an array, pvszsp is an array of ub4s. On return, for OUT bind
variables, this points to sizes of the named data types and REFs received. pvszsp is
ignored if the OCI_DATA_AT_EXEC mode is set. Then the size of the buffer is taken at run
time.
indpp (IN/OUT) [optional]
Address of the program variable buffer containing the parallel indicator structure. For
an array, indpp points to an array of pointers. When the bind variable is also an OUT
bind variable, memory is allocated in the object cache, to store the OUT indicator
values. At the end of the execute operation when all OUT values have been received,
indpp points to the pointers of these newly allocated indicator structures. Required
only for SQLT_NTY binds. The indpp parameter is ignored if the OCI_DATA_AT_EXEC
mode is set. Then the indicator is requested at run time.
indszp (IN/OUT)
Points to the size of the IN indicator structure program variable. For an array, it is an
array of sb2s. On return for OUT bind variables, this points to sizes of the received
OUT indicator structures. indszp is ignored if the OCI_DATA_AT_EXEC mode is set. Then
the indicator size is requested at run time.

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Comments
This function sets up additional attributes for binding a named data type or a REF. An
error is returned if this function is called when the OCI environment has been initialized
in non-object mode.
This call takes as a parameter a type descriptor object (TDO) of data type OCIType for
the named data type being defined. The TDO can be retrieved with a call to
OCITypeByName().
If the OCI_DATA_AT_EXEC mode was specified in OCIBindByName() or OCIBindByName2() or
OCIBindByPos() or OCIBindByPos2(), the pointers to the IN buffers are obtained either
using the callback icbfp registered in the OCIBindDynamic() call or by the
OCIStmtSetPieceInfo() call.
The buffers are dynamically allocated for the OUT data. The pointers to these buffers
are returned either by:
•

Calling ocbfp() registered by the OCIBindDynamic()

•

Setting the pointer to the buffer in the buffer passed in by OCIStmtSetPieceInfo()
called when OCIStmtExecute() returned OCI_NEED_DATA

The memory of these client library-allocated buffers must be freed when not in use
anymore by using the OCIObjectFree() call.
Related Topics
•

OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIBindArrayOfStruct()
Sets up the skip parameters for a static array bind.

•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCIStmtSetPieceInfo()
Sets piece information for a piecewise operation.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIObjectFree()
Frees and unpins an object instance.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.8 OCIDefineArrayOfStruct()
Specifies additional attributes necessary for a static array define, used in an array of
structures (multirow, multicolumn) fetch.
Purpose
Specifies additional attributes necessary for a static array define, used in an array of
structures (multirow, multicolumn) fetch.
Syntax
sword OCIDefineArrayOfStruct ( OCIDefine
OCIError
ub4
ub4
ub4
ub4

*defnp,
*errhp,
pvskip,
indskip,
rlskip,
rcskip );

Parameters
defnp (IN/OUT)
The handle to the define structure that was returned by a call to OCIDefineByPos() or
OCIDefineByPos2().
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
pvskip (IN)
Skip parameter for the next data value.
indskip (IN)
Skip parameter for the next indicator location.
rlskip (IN)
Skip parameter for the next return length value.
rcskip (IN)
Skip parameter for the next return code.
Comments
This call follows a call to OCIDefineByPos() or OCIDefineByPos2(). If the application is
binding an array of structures involving objects, it must call OCIDefineObject() first, and
then call OCIDefineArrayOfStruct().
Related Topics
•

OCIDefineByPos()
Associates an item in a select list with the type and output data buffer.

•

OCIDefineByPos2()
Associates an item in a select list with the type and output data buffer. Use this call
when working with data types when actual lengths exceed UB2MAXVAL on the client.

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•

OCIDefineObject()
Sets up additional attributes necessary for a named data type or REF define.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Skip Parameters

25.4.9 OCIDefineByPos()
Associates an item in a select list with the type and output data buffer.
Purpose
Associates an item in a select list with the type and output data buffer.
Syntax
sword OCIDefineByPos ( OCIStmt
*stmtp,
OCIDefine **defnpp,
OCIError
*errhp,
ub4
position,
void
*valuep,
sb4
value_sz,
ub2
dty,
void
*indp,
ub2
*rlenp,
ub2
*rcodep,
ub4
mode );

Parameters
stmtp (IN/OUT)
A handle to the requested SQL query operation.
defnpp (IN/OUT)
A pointer to a pointer to a define handle. If this parameter is passed as NULL, this call
implicitly allocates the define handle. For a redefine, a non-NULL handle can be passed
in this parameter. This handle is used to store the define information for this column.

Note:
You must keep track of this pointer. If a second call to OCIDefineByPos() is
made for the same column position, there is no guarantee that the same
pointer will be returned.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.

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position (IN)
The position of this value in the select list. Positions are 1-based and are numbered
from left to right. The value 0 selects ROWIDs (the globally unique identifier for a row in
a table).
valuep (IN/OUT)
A pointer to a buffer or an array of buffers of the type specified in the dty parameter. A
number of buffers can be specified when results for more than one row are desired in
a single fetch call.
For a LOB, the buffer pointer must be a pointer to a LOB locator of type
OCILobLocator. Give the address of the pointer.
When mode is set to OCI_IOV, pass the base address of the OCIIOV struct.
value_sz (IN)
The size of each valuep buffer in bytes. If the data is stored internally in VARCHAR2
format, the number of characters desired, if different from the buffer size in bytes, can
be specified by using OCIAttrSet().
In a multibyte conversion environment, a truncation error is generated if the number of
bytes specified is insufficient to handle the number of characters needed.
If the OCI_ATTR_CHARSET_ID attribute is set to OCI_UTF16ID (replaces the deprecated
OCI_UCS2ID, which is retained for backward compatibility), all data passed to and
received with the corresponding define call is assumed to be in UTF-16 encoding.
When mode is set to OCI_IOV, pass the size of the data value.

See Also:
Bind Handle Attributes
dty (IN)
The data type. Named data type (SQLT_NTY) and REF (SQLT_REF) are valid only if
the environment has been initialized in object mode.
SQLT_CHR and SQLT_LNG can be specified for CLOB columns, and SQLT_BIN and
SQLT_LBI can be specified for BLOB columns.

See Also:
Data Types for a listing of data type codes and values
indp (IN)
Pointer to an indicator variable or array. For scalar data types, pointer to sb2 or an
array of sb2s. Ignored for SQLT_NTY defines. For SQLT_NTY defines, a pointer to a
named data type indicator structure or an array of named data type indicator
structures is associated by a subsequent OCIDefineObject() call.

See Also:
Indicator Variables

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rlenp (IN/OUT)
Pointer to array of length of data fetched.
When OCIEnvNlsCreate() (which is the recommended OCI environment handle
creation interface) is used, then rlenp lengths are consistently reported in bytes. The
same treatment consistently also holds for the length prefix in SQLT_VCS (2-byte length
prefix) and SQLT_LVC (4-byte length prefix) types. There are no special exceptions for
UCS2 or for NCHAR cases.
When the older OCI environment handle creation interfaces are used (either
OCIEnvCreate() or deprecated OCIEnvInit()), rlenp lengths are in bytes in general.
However, rlenp lengths are reported in characters when either the character set is
OCI_UC2ID (= OCI_UTF16ID) or when OCI_ATTR_CHAR_COUNT attribute is set on the
corresponding OCIBind handle. The same treatment holds for the length prefix in
SQLT_VCS (2-byte length prefix) and SQLT_LVC (4-byte length prefix) types.
rcodep (OUT)
Pointer to array of column-level return codes.
mode (IN)
The valid modes are:
•

OCI_DEFAULT - This is the default mode.

•

OCI_DEFINE_SOFT - Soft define mode. This mode increases the performance of the
call. If this is the first define, or some input parameter such as dty or value_sz is

changed from the previous define, this mode is ignored. Unexpected behavior
results if an invalid define handle is passed. An error is returned if the statement is
not executed.
•

OCI_DYNAMIC_FETCH - For applications requiring dynamically allocated data at the

time of fetch, this mode must be used. You can define a callback using the
OCIDefineDynamic() call. The value_sz parameter defines the maximum size of the

data that is to be provided at run time. When the client library needs a buffer to
return the fetched data, the callback is invoked to provide a runtime buffer into
which a piece or all the data is returned.

See Also:
Implicit Fetching of ROWIDs
•

OCI_IOV - Define noncontiguous addresses of data. The valuep parameter must be
of the type OCIIOV *. This mode is intended to be used for scatter or gather

binding, which allows multiple buffers to be bound or defined to a position, for
example column A for the first 10 rows in one buffer, next 5 rows in one buffer, and
the remaining 25 rows in another buffer. That eliminates the need to allocate and
copy all of them into one big buffer while doing the array execute operation.

See Also:
About Binding and Defining Multiple Buffers

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Comments
This call defines an output buffer that receives data retrieved from Oracle Database.
The define is a local step that is necessary when a SELECT statement returns data to
your OCI application.
This call also implicitly allocates the define handle for the select-list item. If a non-NULL
pointer is passed in *defnpp, OCI assumes that this points to a valid handle that has
been previously allocated with a call to OCIHandleAlloc() or OCIDefineByPos() or
OCIDefineByPos2(). This would be true for an application that is redefining a handle to a
different address so that it can reuse the same define handle for multiple fetches.
Defining attributes of a column for a fetch is done in one or more calls. The first call is
to OCIDefineByPos() or OCIDefineByPos2(), which defines the minimal attributes required
to specify the fetch.
Following the call to OCIDefineByPos() or OCIDefineByPos2() additional define calls may
be necessary for certain data types or fetch modes:
•

A call to OCIDefineArrayOfStruct() is necessary to set up skip parameters for an
array fetch of multiple columns.

•

A call to OCIDefineObject() is necessary to set up the appropriate attributes of a
named data type (that is, object or collection) or REF fetch. In this case, the data
buffer pointer in OCIDefineByPos() or OCIDefineByPos2() is ignored.

•

Both OCIDefineArrayOfStruct() and OCIDefineObject() must be called after
OCIDefineByPos() or OCIDefineByPos2() to fetch multiple rows with a column of
named data types.

For a LOB define, the buffer pointer must be a pointer to a LOB locator of type
OCILobLocator, allocated by the OCIDescriptorAlloc() call. LOB locators, and not LOB
values, are always returned for a LOB column. LOB values can then be fetched using
OCI LOB calls on the fetched locator. This same mechanism applies for all descriptor
data types.
For NCHAR (fixed and varying length), the buffer pointer must point to an array of
bytes sufficient for holding the required NCHAR characters.
Nested table columns are defined and fetched like any other named data type.
When defining an array of descriptors or locators, you should pass in an array of
pointers to descriptors or locators.
When doing an array define for character columns, you should pass in an array of
character buffers.
If the mode parameter in this call is set to OCI_DYNAMIC_FETCH, the client application can
fetch data dynamically at run time. Runtime data can be provided in one of two ways:
•

Callbacks using a user-defined function that must be registered with a subsequent
call to OCIDefineDynamic(). When the client library needs a buffer to return the
fetched data, the callback is invoked and the runtime buffers provided return a
piece or all of the data.

•

A polling mechanism using calls supplied by OCI. This mode is assumed if no
callbacks are defined. In this case, the fetch call returns the OCI_NEED_DATA error
code, and a piecewise polling method is used to provide the data.

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See Also:
–

Runtime Data Allocation and Piecewise Operations in OCI for more
information about using the OCI_DYNAMIC_FETCH mode

–

Overview of Defining in OCI for more information about defines

–

Implicit Fetching of ROWIDs

Related Topics
•

OCIDefineArrayOfStruct()
Specifies additional attributes necessary for a static array define, used in an array
of structures (multirow, multicolumn) fetch.

•

OCIDefineDynamic()
Sets the additional attributes required if the OCI_DYNAMIC_FETCH mode was selected
in OCIDefineByPos() or OCIDefineByPos2().

•

OCIDefineObject()
Sets up additional attributes necessary for a named data type or REF define.

•

OCIDefineByPos2()
Associates an item in a select list with the type and output data buffer. Use this call
when working with data types when actual lengths exceed UB2MAXVAL on the client.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.10 OCIDefineByPos2()
Associates an item in a select list with the type and output data buffer. Use this call
when working with data types when actual lengths exceed UB2MAXVAL on the client.
Purpose
Associates an item in a select list with the type and output data buffer. Use this call
instead of OCIDefineByPos() when working with data types when actual lengths exceed
UB2MAXVAL on the client.

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Syntax
sword OCIDefineByPos2 ( OCIStmt
*stmtp,
OCIDefine **defnpp,
OCIError
*errhp,
ub4
position,
void
*valuep,
sb8
value_sz,
ub2
dty,
void
*indp,
ub4
*rlenp,
ub2
*rcodep,
ub4
mode );

Parameters
stmtp (IN/OUT)
A handle to the requested SQL query operation.
defnpp (IN/OUT)
A pointer to a pointer to a define handle. If this parameter is passed as NULL, this call
implicitly allocates the define handle. For a redefine, a non-NULL handle can be passed
in this parameter. This handle is used to store the define information for this column.

Note:
You must keep track of this pointer. If a second call to OCIDefineByPos() is
made for the same column position, there is no guarantee that the same
pointer will be returned.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
position (IN)
The position of this value in the select list. Positions are 1-based and are numbered
from left to right. The value 0 selects ROWIDs (the globally unique identifier for a row in
a table).
valuep (IN/OUT)
A pointer to a buffer or an array of buffers of the type specified in the dty parameter. A
number of buffers can be specified when results for more than one row are desired in
a single fetch call.
For a LOB, the buffer pointer must be a pointer to a LOB locator of type
OCILobLocator. Give the address of the pointer.
When mode is set to OCI_IOV, pass the base address of the OCIIOV struct.
value_sz (IN)
The size of each valuep buffer in bytes. If the data is stored internally in VARCHAR2
format, the number of characters desired, if different from the buffer size in bytes, can
be specified as additional bytes by using OCIAttrSet().
If the value of value_sz > SB4MAXVAL, an ORA-24452 error will be issued, meaning that
values > SB4MAXVAL are not supported in Release 12.1 or later.

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In a multibyte conversion environment, a truncation error is generated if the number of
bytes specified is insufficient to handle the number of characters needed.
If the OCI_ATTR_CHARSET_ID attribute is set to OCI_UTF16ID (replaces the deprecated
OCI_UCS2ID, which is retained for backward compatibility), all data passed to and
received with the corresponding define call is assumed to be in UTF-16 encoding.
When mode is set to OCI_IOV, pass the size of the data value.

See Also:
Bind Handle Attributes
dty (IN)
The data type. Named data type (SQLT_NTY) and REF (SQLT_REF) are valid only if
the environment has been initialized in object mode.
SQLT_CHR and SQLT_LNG can be specified for CLOB columns, and SQLT_BIN and
SQLT_LBI can be specified for BLOB columns.

See Also:
Data Types for a listing of data type codes and values
indp (IN)
Pointer to an indicator variable or array. For scalar data types, pointer to sb2 or an
array of sb2s. Ignored for SQLT_NTY defines. For SQLT_NTY defines, a pointer to a
named data type indicator structure or an array of named data type indicator
structures is associated by a subsequent OCIDefineObject() call.

See Also:
Indicator Variables
rlenp (IN/OUT)
Pointer to array of length of data fetched.
When OCIEnvNlsCreate() (which is the recommended OCI environment handle
creation interface) is used, then rlenp lengths are consistently reported in bytes. The
same treatment consistently also holds for the length prefix in SQLT_VCS (2-byte length
prefix) and SQLT_LVC (4-byte length prefix) types. There are no special exceptions for
UCS2 or for NCHAR cases.
When the older OCI environment handle creation interfaces are used (either
OCIEnvCreate() or deprecated OCIEnvInit()), rlenp lengths are in bytes in general.
However, rlenp lengths are reported in characters when either the character set is
OCI_UC2ID (= OCI_UTF16ID) or when OCI_ATTR_CHAR_COUNT attribute is set on the
corresponding OCIBind handle. The same treatment holds for the length prefix in
SQLT_VCS (2-byte length prefix) and SQLT_LVC (4-byte length prefix) types.
rcodep (OUT)
Pointer to array of column-level return codes.

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mode (IN)
The valid modes are:
•

OCI_DEFAULT - This is the default mode.

•

OCI_DEFINE_SOFT - Soft define mode. This mode increases the performance of the
call. If this is the first define, or some input parameter such as dty or value_sz is

changed from the previous define, this mode is ignored. Unexpected behavior
results if an invalid define handle is passed. An error is returned if the statement is
not executed.
•

OCI_DYNAMIC_FETCH - For applications requiring dynamically allocated data at the

time of fetch, this mode must be used. You can define a callback using the
OCIDefineDynamic() call. The value_sz parameter defines the maximum size of the

data that is to be provided at run time. When the client library needs a buffer to
return the fetched data, the callback is invoked to provide a runtime buffer into
which a piece or all the data is returned.

See Also:
Implicit Fetching of ROWIDs
•

OCI_IOV - Define noncontiguous addresses of data. The valuep parameter must be
of the type OCIIOV *. This mode is intended to be used for scatter or gather

binding, which allows multiple buffers to be bound or defined to a position, for
example column A for the first 10 rows in one buffer, next 5 rows in one buffer, and
the remaining 25 rows in another buffer. That eliminates the need to allocate and
copy all of them into one big buffer while doing the array execute operation.

See Also:
About Binding and Defining Multiple Buffers

Comments
This call defines an output buffer that receives data retrieved from Oracle Database.
The define is a local step that is necessary when a SELECT statement returns data to
your OCI application.
This call also implicitly allocates the define handle for the select-list item. If a non-NULL
pointer is passed in *defnpp, OCI assumes that this points to a valid handle that has
been previously allocated with a call to OCIHandleAlloc() or OCIDefineByPos2(). This
would be true for an application that is redefining a handle to a different address so
that it can reuse the same define handle for multiple fetches.
Defining attributes of a column for a fetch is done in one or more calls. The first call is
to OCIDefineByPos2(), which defines the minimal attributes required to specify the fetch.
Following the call to OCIDefineByPos2() additional define calls may be necessary for
certain data types or fetch modes:
•

A call to OCIDefineArrayOfStruct() is necessary to set up skip parameters for an
array fetch of multiple columns.

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•

A call to OCIDefineObject() is necessary to set up the appropriate attributes of a
named data type (that is, object or collection) or REF fetch. In this case, the data
buffer pointer in OCIDefineByPos2() is ignored.

•

Both OCIDefineArrayOfStruct() and OCIDefineObject() must be called after
OCIDefineByPos2() to fetch multiple rows with a column of named data types.

For a LOB define, the buffer pointer must be a pointer to a LOB locator of type
OCILobLocator, allocated by the OCIDescriptorAlloc() call. LOB locators, and not LOB
values, are always returned for a LOB column. LOB values can then be fetched using
OCI LOB calls on the fetched locator. This same mechanism applies for all descriptor
data types.
For NCHAR (fixed and varying length), the buffer pointer must point to an array of
bytes sufficient for holding the required NCHAR characters.
Nested table columns are defined and fetched like any other named data type.
When defining an array of descriptors or locators, you should pass in an array of
pointers to descriptors or locators.
When doing an array define for character columns, you should pass in an array of
character buffers.
If the mode parameter in this call is set to OCI_DYNAMIC_FETCH, the client application can
fetch data dynamically at run time. Runtime data can be provided in one of two ways:
•

Callbacks using a user-defined function that must be registered with a subsequent
call to OCIDefineDynamic(). When the client library needs a buffer to return the
fetched data, the callback is invoked and the runtime buffers provided return a
piece or all of the data.

•

A polling mechanism using calls supplied by OCI. This mode is assumed if no
callbacks are defined. In this case, the fetch call returns the OCI_NEED_DATA error
code, and a piecewise polling method is used to provide the data.

See Also:
–

Runtime Data Allocation and Piecewise Operations in OCI for more
information about using the OCI_DYNAMIC_FETCH mode

–

Overview of Defining in OCI for more information about defines

–

Implicit Fetching of ROWIDs

Related Topics
•

OCIDefineArrayOfStruct()
Specifies additional attributes necessary for a static array define, used in an array
of structures (multirow, multicolumn) fetch.

•

OCIDefineDynamic()
Sets the additional attributes required if the OCI_DYNAMIC_FETCH mode was selected
in OCIDefineByPos() or OCIDefineByPos2().

•

OCIDefineObject()
Sets up additional attributes necessary for a named data type or REF define.

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•

OCIDefineByPos()
Associates an item in a select list with the type and output data buffer.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

25.4.11 OCIDefineDynamic()
Sets the additional attributes required if the OCI_DYNAMIC_FETCH mode was selected in
OCIDefineByPos() or OCIDefineByPos2().
Purpose
Sets the additional attributes required if the OCI_DYNAMIC_FETCH mode was selected in
OCIDefineByPos() or OCIDefineByPos2().
Syntax
sword OCIDefineDynamic ( OCIDefine *defnp,
OCIError
*errhp,
void
*octxp,
OCICallbackDefine
void
OCIDefine
ub4
void
ub4
ub1
void
ub2

(ocbfp)(
*octxp,
*defnp,
iter,
**bufpp,
**alenpp,
*piecep,
**indpp,
**rcodep );

Parameters
defnp (IN/OUT)
The handle to a define structure returned by a call to OCIDefineByPos().
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.

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octxp (IN)
Points to a context for the callback function.
ocbfp (IN)
Points to a callback function. This is invoked at run time to get a pointer to the buffer
into which the fetched data or a piece of it is to be retrieved. The callback also
specifies the indicator, the return code, and the lengths of the data piece and
indicator.

Note:
Normally, in an OCI function, an IN parameter refers to data being passed to
OCI, and an OUT parameter refers to data coming back from OCI. For
callbacks, this is reversed. IN means that data is coming from OCI into the
callback, and OUT means that data is coming out of the callback and going to
OCI.
The callback parameters are:
octxp (IN/OUT)
A context pointer passed as an argument to all the callback functions. When the client
library needs a buffer to return the fetched data, the callback is invoked and the
runtime buffers provided return a piece or all of the data.
defnp (IN)
The define handle.
iter (IN)
Specifies which row of this current fetch; 0-based.
bufpp (OUT)
Returns a pointer to a buffer to store the column value; that is, *bufpp points to some
appropriate storage for the column value.
alenpp (IN/OUT)
Used by the application to set the size of the storage it is providing in *bufpp. After
data is fetched into the buffer, alenpp indicates the actual size of the data in bytes. If
the buffer length provided in the first call is insufficient to store all the data returned by
the server, then the callback is called again, and so on.
piecep (IN/OUT)
Returns a piece value from the callback (application) to OCI, as follows:
The piecep parameter indicates whether the piece to be fetched is the first piece,
OCI_FIRST_PIECE, a subsequent piece, OCI_NEXT_PIECE, or the last piece,
OCI_LAST_PIECE. The program can process the piece the next time the callback is
called, or after the series of callbacks is over.
•

IN - The value can be OCI_ONE_PIECE, OCI_FIRST_PIECE, or OCI_NEXT_PIECE.

•

OUT - Depends on the IN value:

–

The OUT value can be OCI_ONE_PIECE if the IN value was OCI_ONE_PIECE.

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–

The OUT value can be OCI_ONE_PIECE or OCI_FIRST_PIECE if the IN value was
OCI_FIRST_PIECE.

–

The OUT value can be OCI_NEXT_PIECE or OCI_LAST_PIECE if the IN value was
OCI_NEXT_PIECE.

indpp (IN)
Indicator variable pointer.
rcodep (IN)
Return code variable pointer.
Comments
This call is used to set the additional attributes required if the OCI_DYNAMIC_FETCH mode
has been selected in a call to OCIDefineByPos() or OCIDefineByPos2(). If
OCI_DYNAMIC_FETCH mode was selected, and the call to OCIDefineDynamic() is skipped,
then the application can fetch data piecewise using OCI calls (OCIStmtGetPieceInfo()
and OCIStmtSetPieceInfo()).

Note:
After you use OCIEnvNlsCreate() to create the environment handle, the actual
lengths and returned lengths of bind and define handles are always in
number of bytes.

Related Topics
•

OCIDefineObject()
Sets up additional attributes necessary for a named data type or REF define.

•

OCIBindDynamic()
Registers user callbacks for dynamic data allocation.

•

OCIDefineByPos()
Associates an item in a select list with the type and output data buffer.

•

OCIDefineByPos2()
Associates an item in a select list with the type and output data buffer. Use this call
when working with data types when actual lengths exceed UB2MAXVAL on the client.

•

OCIStmtGetPieceInfo()
Returns piece information for a piecewise operation.

•

OCIStmtSetPieceInfo()
Sets piece information for a piecewise operation.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

See Also:
Runtime Data Allocation and Piecewise Operations in OCI for more
information about OCI_DYNAMIC_FETCH mode

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25.4.12 OCIDefineObject()
Sets up additional attributes necessary for a named data type or REF define.
Purpose
Sets up additional attributes necessary for a named data type or REF define.
Syntax
sword OCIDefineObject ( OCIDefine
*defnp,
OCIError
*errhp,
const OCIType *type,
void
**pgvpp,
ub4
*pvszsp,
void
**indpp,
ub4
*indszp );

Parameters
defnp (IN/OUT)
A define handle previously allocated in a call to OCIDefineByPos() or
OCIDefineByPos2().
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
type (IN) [optional]
Points to the type descriptor object (TDO) that describes the type of the program
variable. This parameter is optional for variables of type SQLT_REF, and may be passed
as NULL if it is not being used.
pgvpp (IN/OUT)
Points to a pointer to a program variable buffer. For an array, pgvpp points to an array
of pointers. Memory for the fetched named data type instances is dynamically
allocated in the object cache. At the end of the fetch when all the values have been
received, pgvpp points to the pointers to these newly allocated named data type
instances. The application must call OCIObjectFree() to deallocate the named data
type instances when they are no longer needed.

Note:
If the application wants the buffer to be implicitly allocated in the cache,
*pgvpp should be passed in as NULL.

pvszsp (IN/OUT)
Points to the size of the program variable. For an array, it is an array of ub4.
indpp (IN/OUT)
Points to a pointer to the program variable buffer containing the parallel indicator
structure. For an array, points to an array of pointers. Memory is allocated to store the
indicator structures in the object cache. At the end of the fetch when all values have

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been received, indpp points to the pointers to these newly allocated indicator
structures.
indszp (IN/OUT)
Points to the sizes of the indicator structure program variable. For an array, it is an
array of ub4s.
Comments
This function follows a call to OCIDefineByPos() or OCIDefineByPos2() to set initial define
information. This call sets up additional attributes necessary for a named data type
define. An error is returned if this function is called when the OCI environment has
been initialized in non-object mode.
This call takes as a parameter a type descriptor object (TDO) of data type OCIType for
the named data type being defined. The TDO can be retrieved with a call to
OCIDescribeAny().
Related Topics
•

OCIDefineByPos()
Associates an item in a select list with the type and output data buffer.

•

OCIDefineByPos2()
Associates an item in a select list with the type and output data buffer. Use this call
when working with data types when actual lengths exceed UB2MAXVAL on the client.

•

OCIObjectFree()
Frees and unpins an object instance.

•

OCIDescribeAny()
Describes existing schema and subschema objects.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

OCIEnvCreate(), and OCIEnvNlsCreate() for more information about

initializing the OCI process environment
•

About Binding and Defining Multiple Buffers for an example of using
multiple buffers

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25.4.13 OCIDescribeAny()
Describes existing schema and subschema objects.
Purpose
Describes existing schema and subschema objects.
Syntax
sword OCIDescribeAny ( OCISvcCtx
OCIError
void
ub4
ub1
ub1
ub1
OCIDescribe

*svchp,
*errhp,
*objptr,
objptr_len,
objptr_typ,
info_level,
objtyp,
*dschp );

Parameters
svchp (IN)
A service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
objptr (IN)
This parameter can be:
1.

A string containing the name of the object to be described. Must be in the
encoding specified by the charset parameter of a previous call to
OCIEnvNlsCreate().

2.

A pointer to a REF to the TDO (for a type).

3.

A pointer to a TDO (for a type).

These cases are distinguished by passing the appropriate value for objptr_typ. This
parameter must be non-NULL.
In case 1, the string containing the object name should be in the format
name1[.name2 ...][@linkname], such as hr.employees.employee_id@mydb. Database links
are only allowed to Oracle8i or later databases. The object name is interpreted by the
following SQL rules:
•

If only name1 is entered and objtyp is equal to OCI_PTYPE_SCHEMA, then the name
refers to the named schema. The Oracle Database must be release 8.1 or later.

•

If only name1 is entered and objtyp is equal to OCI_PTYPE_DATABASE, then the name
refers to the named database. When describing a remote database with
database_name@db_link_name, the remote Oracle Database must be release 8.1 or
later.

•

If only name1 is entered and objtyp is not equal to OCI_PTYPE_SCHEMA or
OCI_PTYPE_DATABASE, then the name refers to the named object (of type table, view,
procedure, function, package, type, synonym, sequence) in the current schema of

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the current user. When connected to an Oracle7 Server, the only valid types are
procedure and function.
•

If name1.name2.name3 ... is entered, the object name refers to a schema or
subschema object in the schema named name1. For example, in the string
hr.employees.department_id, hr is the name of the schema, employees is the name
of a table in the schema, and department_id is the name of a column in the table.

objnm_len (IN)
The length of the name string pointed to by objptr. Must be nonzero if a name is
passed. Can be zero if objptr is a pointer to a TDO or its REF.
objptr_typ (IN)
The type of object passed in objptr. Valid values are:
•

OCI_OTYPE_NAME, if objptr points to the name of a schema object

•

OCI_OTYPE_REF, if objptr is a pointer to a REF to a TDO

•

OCI_OTYPE_PTR, if objptr is a pointer to a TDO

info_level (IN)
Reserved for future extensions. Pass OCI_DEFAULT.
objtyp (IN)
The type of schema object being described. Valid values are:
•

OCI_PTYPE_TABLE, for tables

•

OCI_PTYPE_VIEW, for views

•

OCI_PTYPE_PROC, for procedures

•

OCI_PTYPE_FUNC, for functions

•

OCI_PTYPE_PKG, for packages

•

OCI_PTYPE_TYPE, for types

•

OCI_PTYPE_SYN, for synonyms

•

OCI_PTYPE_SEQ, for sequences

•

OCI_PTYPE_SCHEMA, for schemas

•

OCI_PTYPE_DATABASE, for databases

•

OCI_PTYPE_UNK, for unknown schema objects

dschp (IN/OUT)
A describe handle that is populated with describe information about the object after
the call. Must be non-NULL.
Comments
This is a generic describe call that describes existing schema objects: tables, views,
synonyms, procedures, functions, packages, sequences, types, schemas, and
databases. In addition, the OCIDescribeAny() call describes all package types and
package type attributes contained in the package. This call also describes subschema
objects, such as a column in a table. This call populates the describe handle with the
object-specific attributes that can be obtained through an OCIAttrGet() call.

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An OCIParamGet() on the describe handle returns a parameter descriptor for a specified
position. Parameter positions begin with 1. Calling OCIAttrGet() on the parameter
descriptor returns the specific attributes of a stored procedure or function parameter,
or a table column descriptor. These subsequent calls do not need an extra round-trip
to the server because the entire schema object description is cached on the client side
by OCIDescribeAny(). Calling OCIAttrGet() on the describe handle also returns the total
number of positions.
If the OCI_ATTR_DESC_PUBLIC attribute is set on the describe handle, then the object
named is looked up as a public synonym when the object does not exist in the current
schema and only name1 is specified.
By default, explicit describe (OCIDescribeAny()) does not list the invisible columns. To
get the user defined invisible column's metadata, you must set the describe handle
attribute OCI_ATTR_SHOW_INVISIBLE_COLUMNS before calling OCIDescribeAny(). To know
whether the column is of an invisible type, you can get the column attribute
OCI_ATTR_INVISIBLE_COL using OCIAttrGet().
The property whether a column is visible or not can be controlled by the user. Invisible
columns are not seen unless specified explicitly in the SELECT list. Any generic access
of a table, such as a SELECT * FROM table-name statement or a DESCRIBE statement, will
not show invisible columns.
Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCIParamGet()
Returns a descriptor of a parameter specified by position in the describe handle or
statement handle.

•

OCIAttrGet()
Gets the value of an attribute of a handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Describing Schema Metadata for more information about describe operations

25.4.14 OCIStmtGetBindInfo()
Gets the bind and indicator variable names.
Purpose
Gets the bind and indicator variable names.
Syntax
sword OCIStmtGetBindInfo ( OCIStmt
OCIError
ub4
ub4

*stmtp,
*errhp,
size,
startloc,

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sb4
OraText
ub1
OraText
ub1
ub1
OCIBind

*found,
*bvnp[],
bvnl[],
*invp[],
inpl[],
dupl[],
*hndl[] );

Parameters
stmtp (IN)
The statement handle prepared by OCIStmtPrepare2().
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
size (IN)
The number of elements in each array.
startloc (IN)
Position of the bind variable at which to start getting bind information.
found (IN)
The expression abs(found) gives the total number of bind variables in the statement
irrespective of the start position. Positive value if the number of bind variables
returned is less than the size provided, otherwise negative.
bvnp (OUT)
Array of pointers to hold bind variable names. Is in the encoding specified by the
charset parameter of a previous call to OCIEnvNlsCreate().
bvnl (OUT)
Array to hold the length of the each bvnp element. The length is in bytes.
invp (OUT)
Array of pointers to hold indicator variable names. Must be in the encoding specified
by the charset parameter of a previous call to OCIEnvNlsCreate().
inpl (OUT)
Array of pointers to hold the length of the each invp element. In number of bytes.
dupl (OUT)
An array whose element value is 0 or 1 depending on whether the bind position is a
duplicate of another.
hndl (OUT)
An array that returns the bind handle if binds have been done for the bind position. No
handle is returned for duplicates.
Comments
This call returns information about bind variables after a statement has been prepared.
This includes bind names, indicator names, and whether binds are duplicate binds.
This call also returns an associated bind handle if there is one. The call sets the found
parameter to the total number of bind variables and not just the number of distinct bind
variables.

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OCI_NO_DATA is returned if the statement has no bind variables or if the starting bind

position specified in the invocation does not exist in the statement.
This function does not include SELECT INTO list variables, because they are not
considered to be binds.
The statement must have been prepared with a call to OCIStmtPrepare2() prior to this
call. The encoding setting in the statement handle determines whether Unicode strings
are retrieved.
This call is processed locally.
Related Topics
•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26
More Oracle Database Access C API
This chapter describes more Oracle Database Access C API OCI relational functions.
This chapter describes more Oracle Database Access C API and completes the
description of the OCI relational functions started in the previous chapter. It includes
information about calling OCI functions in your application, along with detailed
descriptions of each function call.

See Also:
For code examples, see the demonstration programs included with your
Oracle Database installation. For additional information, see OCI
Demonstration Programs.

This chapter contains these topics:
•

Introduction to the Relational Functions

•

Statement Functions

•

LOB Functions

•

Streams Advanced Queuing and Publish-Subscribe Functions

•

Direct Path Loading Functions

•

Thread Management Functions

•

Transaction Functions

•

Sharding Functions

•

Miscellaneous Functions

26.1 Introduction to the Relational Functions
Introduces relational function calls.
This chapter describes the OCI relational function calls. This chapter and the previous
one, cover the functions in the basic OCI.

See Also:
Error Handling in OCI for information about return codes and error handling

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26.1.1 Conventions for OCI Functions
Describes conventions used for OCI functions.
See the Conventions for OCI Functions for the conventions used in describing each
function.

26.2 Statement Functions
Lists and describes the statement functions.
Table 26-1 lists the statement functions that are described in this section. Use
functions that end in "2" for all new applications.
Table 26-1

Statement Functions

Function

Purpose

OCIStmtExecute()

Send statements to server for execution

OCIStmtFetch2()

Fetch rows from a query and fetches a row
from the (scrollable) result set

OCIStmtGetNextResult()

Returns the implicit results from an executed
PL/SQL statement handle

OCIStmtGetPieceInfo()

Get piece information for piecewise operations

OCIStmtPrepare2()

Prepare a SQL or PL/SQL statement for
execution. The user also has the option of
using the statement cache, if it has been
enabled.

OCIStmtRelease()

Release the statement handle

OCIStmtSetPieceInfo()

Set piece information for piecewise operations

26.2.1 OCIStmtExecute()
Associates an application request with a server.
Purpose
Associates an application request with a server.
Syntax
sword OCIStmtExecute ( OCISvcCtx
OCIStmt
OCIError
ub4
ub4
const OCISnapshot
OCISnapshot
ub4

*svchp,
*stmtp,
*errhp,
iters,
rowoff,
*snap_in,
*snap_out,
mode );

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Parameters
svchp (IN/OUT)
Service context handle.
stmtp (IN/OUT)
A statement handle. It defines the statement and the associated data to be executed
at the server. It is invalid to pass in a statement handle that has bind of data types
only supported in release 8.x or later, when svchp points to an Oracle7 server.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information, when
there is an error.
iters (IN)
For non-SELECT statements, the number of times this statement is executed equals
iters - rowoff.
For SELECT statements, if iters is nonzero, then defines must have been done for the
statement handle. The execution fetches iters rows into these predefined buffers and
prefetches more rows depending upon the prefetch row count. If you do not know how
many rows the SELECT statement retrieves, then set iters to zero.
This function returns an error if iters=0 for non-SELECT statements.
This function returns an error if iters is not 1 for DDL statements.

Note:
For array DML operations, set iters <= 32767 to get better performance.
rowoff (IN)
The starting index from which the data in an array bind is relevant for this multiple row
execution.
snap_in (IN)
This parameter is optional. If it is supplied, then it must point to a snapshot descriptor
of type OCI_DTYPE_SNAP. The contents of this descriptor must be obtained from the
snap_out parameter of a previous call. The descriptor is ignored if the SQL is not a
SELECT statement. This facility allows multiple service contexts to Oracle Database to
see the same consistent snapshot of the database's committed data. However,
uncommitted data in one context is not visible to another context even using the same
snapshot.
snap_out (OUT)
This parameter is optional. If it is supplied, then it must point to a descriptor of type
OCI_DTYPE_SNAP. This descriptor is filled in with an opaque representation that is the
current Oracle Database system change number (SCN) suitable as a snap_in input to
a subsequent call to OCIStmtExecute(). To avoid "snapshot too old" errors, do not use
this descriptor any longer than necessary.
mode (IN)
The modes are:
•

OCI_BATCH_ERRORS - See Using Batch Error Mode for information about this mode.

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•

OCI_COMMIT_ON_SUCCESS - When a statement is executed in this mode, the current

transaction is committed after execution, if execution completes successfully.
•

OCI_DEFAULT - Calling OCIStmtExecute() in this mode executes the statement. It also

implicitly returns describe information about the select list.
•

OCI_DESCRIBE_ONLY - This mode is for users who want to describe a query before
execution. Calling OCIStmtExecute() in this mode does not execute the statement,

but it does return the select-list description. To maximize performance, Oracle
recommends that applications execute the statement in default mode and use the
implicit describe that accompanies the execution.
•

OCI_EXACT_FETCH - Used when the application knows in advance exactly how many

rows it is fetching. This mode turns prefetching off for Oracle Database release 8
or later mode, and requires that defines be done before the execute call. Using
this mode cancels the cursor after the desired rows are fetched and may result in
reduced server-side resource usage.
•

OCI_PARSE_ONLY - This mode allows the user to parse the query before execution.

Executing in this mode parses the query and returns parse errors in the SQL, if
any. Users must note that this involves an additional round-trip to the server. To
maximize performance, Oracle recommends that the user execute the statement
in the default mode, which, parses the statement as part of the bundled operation.
•

OCI_STMT_SCROLLABLE_READONLY - Required for the result set to be scrollable. The

result set cannot be updated. See About Fetching Results for more information
about this mode. This mode cannot be used with any other mode.
OCI_RETURN_ROW_COUNT_ARRAY - This mode allows the user to get DML rowcounts per

iteration. It is an error to pass this mode for statements that are not DMLs. See
Statement Handle Attributes for more information. This mode can be used along
with OCI_BATCH_ERRORS.
The modes are not mutually exclusive; you can use them together, except for
OCI_STMT_SCROLLABLE_READONLY.

Comments
This function is used to execute a prepared SQL statement. Using an execute call, the
application associates a request with a server.
If a SELECT statement is executed, then the description of the select list is available
implicitly as a response. This description is buffered on the client side for describes,
fetches, and define type conversions. Hence it is optimal to describe a select list only
after an execute.

See Also:
About Describing Select-List Items

Also for SELECT statements, some results are available implicitly. Rows are received
and buffered at the end of the execute. For queries with small row count, a prefetch
causes memory to be released in the server if the end of fetch is reached, an
optimization that may result in memory usage reduction. The set attribute call has
been defined to set the number of rows to be prefetched for each result set.

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For SELECT statements, at the end of the execute, the statement handle implicitly
maintains a reference to the service context on which it is executed. It is the
developer's responsibility to maintain the integrity of the service context. The implicit
reference is maintained until the statement handle is freed or the fetch is canceled or
an end of fetch condition is reached.
To reexecute a DDL statement, you must prepare the statement again using
OCIStmtPrepare2().

Note:
If output variables are defined for a SELECT statement before a call to
OCIStmtExecute(), the number of rows specified by iters are fetched directly
into the defined output buffers and additional rows equivalent to the prefetch
count are prefetched. If there are no additional rows, then the fetch is
complete without calling OCIStmtFetch2() or deprecated OCIStmtFetch().

Related Topics
•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Polling Mode Operations in OCI

26.2.2 OCIStmtFetch2()
Fetches a row from the (scrollable) result set.
Purpose
Fetches a row from the (scrollable) result set. You are encouraged to use this fetch
call instead of the deprecated call OCIStmtFetch().
Syntax
sword OCIStmtFetch2 ( OCIStmt
OCIError
ub4
ub2
sb4
ub4

*stmthp,
*errhp,
nrows,
orientation,
fetchOffset,
mode );

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Parameters
stmthp (IN/OUT)
This is the statement handle of the (scrollable) result set.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information if an
error occurs.
nrows (IN)
Number of rows to be fetched from the current position.
orientation (IN)
The acceptable values are:
•

OCI_DEFAULT - Has the same effect as OCI_FETCH_NEXT

•

OCI_FETCH_CURRENT - Gets the current row.

•

OCI_FETCH_NEXT - Gets the next row from the current position. It is the default (has
the same effect as OCI_DEFAULT). Use for a nonscrollable statement handle.

•

OCI_FETCH_FIRST - Gets the first row in the result set.

•

OCI_FETCH_LAST - Gets the last row in the result set.

•

OCI_FETCH_PRIOR - Positions the result set on the previous row from the current row

in the result set. You can fetch multiple rows using this mode, from the "previous
row" also.
•

OCI_FETCH_ABSOLUTE - Fetches the row number (specified by fetchOffset parameter)

in the result set using absolute positioning.
•

OCI_FETCH_RELATIVE - Fetches the row number (specified by fetchOffset parameter)

in the result set using relative positioning.
fetchOffset (IN)
The offset to be used with the orientation parameter for changing the current row
position.
mode (IN)
Pass in OCI_DEFAULT.
Comments
The fetch call works similarly to the deprecated OCIStmtFetch() call, but with the
addition of the fetchOffset parameter. It can be used on any statement handle,
whether it is scrollable or not. For a nonscrollable statement handle, the only
acceptable value of orientation is OCI_FETCH_NEXT, and the fetchOffset parameter is
ignored.
For new applications you are encouraged to use this call, OCIStmtFetch2().
A fetchOffset with orientation set to OCI_FETCH_RELATIVE is equivalent to all of the
following:
•

OCI_FETCH_CURRENT with a value of fetchOffset equal to 0

•

OCI_FETCH_NEXT with a value of fetchOffset equal to 1

•

OCI_FETCH_PRIOR with a value of fetchOffset equal to -1

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OCI_ATTR_UB8_ROW_COUNT contains the highest absolute row value that was fetched.

All other orientation modes besides OCI_FETCH_ABSOLUTE and OCI_FETCH_RELATIVE ignore
the fetchOffset value.
This call can also be used to determine the number of rows in the result set by using
OCI_FETCH_LAST and then calling OCIAttrGet() on OCI_ATTR_CURRENT_POSITION. But the
response time of this call can be high. If nrows is set to be greater than 1 with
OCI_FETCH_LAST orientation, nrows is considered to be 1.
The return codes are the same as for deprecated OCIStmtFetch(), except that
OER(1403) with return code OCI_NO_DATA is returned every time a fetch on a scrollable
statement handle (or execute) is made and not all rows requested by the application
could be fetched.
If you call OCIStmtFetch2() with the nrows parameter set to 0, this cancels the cursor.
The scrollable statement handle must be explicitly canceled (that is, fetch with 0 rows)
or freed to release server-side resources for the scrollable cursor. A nonscrollable
statement handle is implicitly canceled on receiving the OER(1403).
Use OCI_ATTR_ROWS_FETCHED to find the number of rows that were successfully fetched
into the user's buffers in the last fetch call.
Related Topics
•

OCIStmtFetch()
This function was deprecated in a release previous to Oracle 11g R2 (11.2).

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

About Using Scrollable Cursors in OCI
A cursor is a current position in a result set.

•

Polling Mode Operations in OCI
OCI has calls that poll for completion.

26.2.3 OCIStmtGetNextResult()
Returns the implicit results from an executed PL/SQL statement handle.
Purpose
Returns the implicit results from an executed PL/SQL statement handle.

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Syntax
sword OCIStmtGetNextResult (OCIStmt
OCIError
void
ub4
ub4

*stmthp,
*errhp,
**result,
*rtype,
mode)

Parameters
stmthp (IN)
The executed statement handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
result (OUT)
The next implicit result from the executed PL/SQL statement.
rtype (OUT)
The type of the implicit result. The only possible value is OCI_RESULT_TYPE_SELECT.
mode (IN)
The only possible value is OCI_DEFAULT (default mode).
Comments
Each call to OCIStmtGetNextResult() retrieves a single implicit result in the order in
which they were returned from the PL/SQL procedure or block. If no more results are
available, then OCI_NO_DATA is returned. If rtype is OCI_RESULT_TYPE_SELECT, then the
returned result can be cast as an OCI statement handle, and is allocated by OCI.
Applications can do normal OCI define and fetch calls to fetch rows from the implicit
result sets. The returned OCI statement handle cannot be freed explicitly. All implicit
result sets are automatically closed and freed when the top-level statement handle is
freed or released.
See OCI_ATTR_IMPLICIT_RESULT_COUNT for information about this statement
handle attribute, which returns the total number of implicit results available on the toplevel OCI statement handle.
Returns
Returns one of the following:
•

OCI_ERROR

•

OCI_SUCCESS

•

OCI_NO_DATA - When all implicit result sets have been retrieved from the top-level

statement handle
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.2.4 OCIStmtGetPieceInfo()
Returns piece information for a piecewise operation.
Purpose
Returns piece information for a piecewise operation.
Syntax
sword OCIStmtGetPieceInfo( const OCIStmt
OCIError
void
ub4
ub1
ub4
ub4
ub1

*stmtp,
*errhp,
**hndlpp,
*typep,
*in_outp,
*iterp,
*idxp,
*piecep );

Parameters
stmtp (IN)
The statement that when executed returned OCI_NEED_DATA.
errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
hndlpp (OUT)
Returns a pointer to the bind or define handle of the bind or define whose run-time
data is required or is being provided.
typep (OUT)
The type of the handle pointed to by hndlpp: OCI_HTYPE_BIND (for a bind handle) or
OCI_HTYPE_DEFINE (for a define handle).
in_outp (OUT)
Returns OCI_PARAM_IN if the data is required for an IN bind value. Returns
OCI_PARAM_OUT if the data is available as an OUT bind variable or a define position
value.
iterp (OUT)
Returns the row number of a multiple row operation.
idxp (OUT)
The index of an array element of a PL/SQL array bind operation.
piecep (OUT)
Returns one of these defined values: OCI_ONE_PIECE, OCI_FIRST_PIECE, OCI_NEXT_PIECE,
or OCI_LAST_PIECE.
Comments
When an execute or fetch call returns OCI_NEED_DATA to get or return a dynamic bind,
define value, or piece, OCIStmtGetPieceInfo() returns the relevant information: bind or
define handle, iteration, index number, and which piece.

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Related Topics
•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIStmtFetch2()
Fetches a row from the (scrollable) result set.

•

OCIStmtSetPieceInfo()
Sets piece information for a piecewise operation.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Polling Mode Operations in OCI
OCI has calls that poll for completion.

See Also:
•

Runtime Data Allocation and Piecewise Operations in OCI for more
information about using OCIStmtGetPieceInfo()

26.2.5 OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.
Purpose
Prepares a SQL or PL/SQL statement for execution. The user has the option of using
the statement cache, if it has been enabled.
Oracle strongly encourages use of OCIStmtPrepare2() in all OCI applications instead of
the deprecated call OCIStmtPrepare().
Syntax
sword OCIStmtPrepare2 ( OCISvcCtx
OCIStmt
OCIError
const OraText
ub4
const OraText
ub4
ub4
ub4

*svchp,
**stmthp,
*errhp,
*stmttext,
stmt_len,
*key,
keylen,
language,
mode );

Parameters
svchp (IN)
The service context to be associated with the statement.

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stmthp (OUT)
Pointer to the statement handle returned.
errhp (IN)
A pointer to the error handle for diagnostics.
stmttext (IN)
The statement text. The semantics of the stmttext are same as those of
OCIStmtPrepare(); that is, the string must be NULL-terminated.
stmt_len (IN)
The statement text length.
key (IN)
For statement caching only. The key to be used for searching the statement in the
statement cache. If the key is passed in, then the statement text and other parameters
are ignored and the search is solely based on the key.
keylen (IN)
For statement caching only. The length of the key.
language (IN)
Specifies V7, or native syntax. Possible values are as follows:
•

OCI_V7_SYNTAX - V7 ORACLE parsing syntax.

•

OCI_NTV_SYNTAX - Syntax depends upon the version of the server.
OCI_FOREIGN_SYNTAX - Specifies the statement to be translated according to the
SQL translation profile set in the session.

mode (IN)
This function can be used with and without statement caching. This is determined at
the time of connection or session pool creation. If caching is enabled for a session,
then all statements in the session have caching enabled, and if caching is not
enabled, then all statements are not cached.
The valid modes are as follows:
•

OCI_DEFAULT - Caching is not enabled. If the statement is not found in the cache,

this mode allocates a new statement handle and prepares the statement handle
for execution. If the statement is not found in the cache and one of the following
circumstances applies, then the subsequent actions follow:

•

–

Only the text has been supplied: a new statement is allocated and prepared
and returned. The tag NULL. OCI_SUCCESS is returned.

–

Only the tag has been supplied: stmthp is NULL. OCI_ERROR is returned.

–

Both text and key were supplied: a new statement is allocated and prepared
and returned. The tag NULL. OCI_SUCCESS_WITH_INFO is returned, as the returned
statement differs from the requested statement in that the tag is NULL.

OCI_PREP2_CACHE_SEARCHONLY - In this case, if the statement is not found (a NULL

statement handle is returned), you must take further action. If the statement is
found, OCI_SUCCESS is returned. Otherwise, OCI_ERROR is returned.
•

OCI_PREP2_GET_PLSQL_WARNINGS - If warnings are enabled in the session and the
PL/SQL program is compiled with warnings, then OCI_SUCCESS_WITH_INFO is the

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return status from the execution. Use OCIErrorGet() to find the new error number
corresponding to the warnings.
•

OCI_PREP2_IMPL_RESULTS_CLIENT - The mode should be passed as
OCI_PREP2_IMPL_RESULTS_CLIENT when this call is made in an external procedure

and implicit results need to be processed. See OCI Support for Implicit Results for
more details.
Related Topics
•

OCIStmtPrepare()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCIStmtRelease()
Releases the statement handle obtained by a call to OCIStmtPrepare2().

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.2.6 OCIStmtRelease()
Releases the statement handle obtained by a call to OCIStmtPrepare2().
Purpose
Releases the statement handle obtained by a call to OCIStmtPrepare2().
Syntax
sword OCIStmtRelease ( OCIStmt
*stmthp,
OCIError
*errhp,
const OraText *key,
ub4
keylen,
ub4
mode );

Parameters
stmthp (IN/OUT)
The statement handle returned by OCIStmtPrepare2().
errhp (IN)
The error handle used for diagnostics.
key (IN)
Only valid for statement caching. The key to be associated with the statement in the
cache. This is a SQL string passed in by the caller. If a NULL key is passed in, the
statement is not tagged.
keylen (IN)
Only valid for statement caching. The length of the key.
mode (IN)
The valid modes are:
•

OCI_DEFAULT

•

OCI_STRLS_CACHE_DELETE - Only valid for statement caching. The statement is not

kept in the cache anymore.

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Related Topics
•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

26.2.7 OCIStmtSetPieceInfo()
Sets piece information for a piecewise operation.
Purpose
Sets piece information for a piecewise operation.
Syntax
sword OCIStmtSetPieceInfo ( void
ub4
OCIError
const void
ub4
ub1
const void
ub2

*hndlp,
type,
*errhp,
*bufp,
*alenp,
piece,
*indp,
*rcodep );

Parameters
hndlp (IN/OUT)
The bind or define handle.
type (IN)
Type of the handle.
errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
bufp (IN/OUT)
A pointer to storage containing the data value or the piece when it is an IN bind
variable; otherwise, bufp is a pointer to storage for getting a piece or a value for OUT
binds and define variables. For named data types or REFs, a pointer to the object or
REF is returned.
alenp (IN/OUT)
The length of the piece or the value. Do not change this parameter between
executions of the same SQL statement.
piece (IN)
The piece parameter. Valid values are:
•

OCI_ONE_PIECE

•

OCI_FIRST_PIECE

•

OCI_NEXT_PIECE

•

OCI_LAST_PIECE

This parameter is used for IN bind variables only.

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indp (IN/OUT)
Indicator. A pointer to an sb2 value or pointer to an indicator structure for named data
types (SQLT_NTY) and REFs (SQLT_REF), that is, depending upon the data type,
*indp is either an sb2 or a void *.
rcodep (IN/OUT)
Return code.
Comments
When an execute call returns OCI_NEED_DATA to get a dynamic IN/OUT bind value or
piece, OCIStmtSetPieceInfo() sets the piece information: the buffer, the length, which
piece is currently being processed, the indicator, and the return code for this column.
Related Topics
•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIStmtExecute()
Associates an application request with a server.

•

OCIStmtFetch2()
Fetches a row from the (scrollable) result set.

•

OCIStmtGetPieceInfo()
Returns piece information for a piecewise operation.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Polling Mode Operations in OCI
OCI has calls that poll for completion.

See Also:
•

Runtime Data Allocation and Piecewise Operations in OCI for more
information about using OCIStmtSetPieceInfo()

26.3 LOB Functions
Table 26-2 lists the LOB functions that use the LOB locator that are described in this
section. Use functions that end in "2" for all new applications.
Beginning with Oracle Database 12c Release 2 (12.2), most LOB functions support
Application Continuity (see When Application Continuity in OCI Can Fail Over for a
complete list). This support also includes some deprecated LOB functions for
compatibility listed in Deprecated Lob Functions.
Beginning with Oracle Database 12c Release 2 (12.2), OCI LOB functions support
distributed operations on remote LOBs (CLOB, BLOB) except for OCI LOB functions
for BFILES. This includes support for certain queries that select a remote LOB locator

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that in previous releases returned an error. The only restriction is that all LOB
functions that take in two locators should have both LOBs collocated at one database.
The following LOB functions throw an error when a remote locator is passed to it:
OCILobAssign(), OCILobLocatorAssign(), OCILobEnableBuffering(),
OCILobDisableBuffering(), OCILobFlushBuffer(), OCILobArrayRead(), OCILobArrayWrite(),
and OCILobLoadFromFile2().

Note:
There is another way of accessing LOBs -- using the data interface for LOBs.
You can bind or define character data for a CLOB column or RAW data for a BLOB
column, as described in these locations:
•

About Binding LOB Data for usage and examples for both INSERT and
UPDATE statements

Table 26-2

•

About Defining LOB Data for usage and examples of SELECT statements

•

LOB and BFILE Operations

LOB Functions

Function

Purpose

OCIDurationBegin()

Start user duration for temporary LOB

OCIDurationEnd()

End user duration for temporary LOB

OCILobAppend()

Append one LOB to another

OCILobArrayRead()

Read LOB data for multiple locators

OCILobArrayWrite()

Write LOB data for multiple locators

OCILobAssign()

Assign one LOB locator to another

OCILobCharSetForm()

Get character set form from LOB locator

OCILobCharSetId()

Get character set ID from LOB locator

OCILobClose()

Close a previously opened LOB

OCILobCopy2()

Copy all or part of one LOB to another. This
function must be used for LOBs of size greater
than 4 GB.

OCILobCreateTemporary()

Create a temporary LOB

OCILobDisableBuffering()

Turn LOB buffering off

OCILobEnableBuffering()

Turn LOB buffering on

OCILobErase2()

Erase a portion of a LOB. This function must be
used for LOBs of size greater than 4 GB.

OCILobFileClose()

Close a previously opened BFILE

OCILobFileCloseAll()

Close all previously opened files

OCILobFileExists()

Check if a file exists on the server

OCILobFileGetName()

Get directory object and file name from the
LOB locator

OCILobFileIsOpen()

Check if file on server is open using this locator

OCILobFileOpen()

Open a BFILE

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Table 26-2

(Cont.) LOB Functions

Function

Purpose

OCILobFileSetName()

Set directory object and file name in the LOB
locator

OCILobFlushBuffer()

Flush the LOB buffer

OCILobFreeTemporary()

Free a temporary LOB

OCILobGetChunkSize()

Get the chunk size of a LOB

OCILobGetContentType()

Retrieve the user-specified content type string
(a file format identifier) for a SecureFile

OCILobGetLength2()

Get length of a LOB. This function must be
used for LOBs of size greater than 4 GB.

OCILobGetOptions()

Get option settings of a SecureFile

OCILobGetStorageLimit()

Get the maximum length of an internal LOB
(BLOB, CLOB, or NCLOB) in bytes

OCILobIsEqual()

Compare two LOB locators for Equality

OCILobIsOpen()

Check to see if a LOB is open

OCILobIsTemporary()

Determine if a given LOB is temporary

OCILobLoadFromFile2()

Load a LOB from a BFILE. This function must
be used for LOBs of size greater than 4 GB.

OCILobLocatorAssign()

Assign one LOB locator to another

OCILobLocatorIsInit()

Check to see if a LOB locator is initialized

OCILobOpen()

Open a LOB

OCILobRead2()

Read a portion of a LOB. This function must be
used for LOBs of size greater than 4 GB.

OCILobSetContentType()

Store the user-specified content type string of
the SecureFile

OCILobSetOptions()

Enable option settings for existing and newly
created SecureFiles

OCILobTrim2()

Truncate a LOB. This function must be used for
LOBs of size greater than 4 GB.

OCILobWrite2()

Write into a LOB. This function must be used
for LOBs of size greater than 4 GB.

OCILobWriteAppend2()

Write data beginning at the end of a LOB. This
function must be used for LOBs of size greater
than 4 GB.

Note the following for parameters in the OCI LOB calls:
•

For fixed-width client-side character sets, the offset and amount parameters are
always in characters for CLOBs and NCLOBs, and in bytes for BLOBs and BFILEs.

•

For varying-width client-side character sets, these rules generally apply:
–

Amount (amtp) parameter - When the amount parameter refers to the serverside LOB, the amount is in characters. When the amount parameter refers to
the client-side buffer, the amount is in bytes.

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For more information, see individual LOB calls, such as OCILobGetLength()
(deprecated), OCILobGetLength2(), OCILobRead() (deprecated), OCILobRead2(),
OCILobWrite() (deprecated), and OCILobWrite2().
–

•

Offset (offset) parameter - Regardless of whether the client-side character set
is varying-width, the offset parameter is always in characters for CLOBs and
NCLOBs and in bytes for BLOBs and BFILEs.

For many of the LOB operations, regardless of the client-side character set, the
amount parameter is in characters for CLOBs and NCLOBs. These LOB operations
include OCILobCopy2(), OCILobErase2(), OCILobGetLength2(), OCILobLoadFromFile2(),
and OCILobTrim2(). All these operations refer to the amount of LOB data on the
server.

A streaming operation means that the LOB is read or written in pieces. Streaming can
be implemented using a polling mechanism or by registering a user-defined callback.

26.3.1 OCIDurationBegin()
Starts a user duration for a temporary LOB.
Purpose
Starts a user duration for a temporary LOB.
Syntax
sword OCIDurationBegin ( OCIEnv
OCIError
const OCISvcCtx
OCIDuration
OCIDuration

*env,
*err,
*svc,
parent,
*duration );

Parameters
env (IN/OUT)
Pass as a NULL pointer.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
svc (IN)
An OCI service context handle. Must be non-NULL.
parent (IN)
The duration number of the parent duration. It is one of these:
•

OCI_DURATION_STATEMENT

•

OCI_DURATION_SESSION

duration (OUT)
An identifier unique to the newly created user duration.
Comments
This function starts a user duration. In release 8.1 or later, user durations can be used
when creating temporary LOBs. A user can have multiple active user durations

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simultaneously. The user durations do not have to be nested. The duration parameter
is used to return a number that uniquely identifies the duration created by this call.
Related Topics
•

Temporary LOB Durations
OCI supports several predefined durations for temporary LOBs, and a set of
functions that the application can use to define application-specific durations.

26.3.2 OCIDurationEnd()
Terminates a user duration for a temporary LOB.
Purpose
Terminates a user duration for a temporary LOB.
Syntax
sword OCIDurationEnd ( OCIEnv
OCIError
const OCISvcCtx
OCIDuration

*env,
*err,
*svc,
duration );

Parameters
env (IN/OUT)
Pass as a NULL pointer.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
svc (IN)
OCI service context. This should be passed as NULL for cartridge services.
duration (IN)
A number to identify the user duration.
Comments
This function terminates a user duration. Temporary LOBs that are allocated for the
user duration are freed.
Related Topics
•

OCIDurationBegin()
Starts a user duration for a temporary LOB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Temporary LOB Durations
OCI supports several predefined durations for temporary LOBs, and a set of
functions that the application can use to define application-specific durations.

Related Topics
•

OCIDurationBegin()
Starts a user duration.

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LOB Functions

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.3 OCILobAppend()
Appends a LOB value at the end of another LOB as specified.
Purpose
Appends a LOB value at the end of another LOB as specified.
Syntax
sword OCILobAppend ( OCISvcCtx
OCIError
OCILobLocator
OCILobLocator

*svchp,
*errhp,
*dst_locp,
*src_locp );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
dst_locp (IN/OUT)
An internal LOB locator uniquely referencing the destination LOB. This locator must
have been a locator that was obtained from the server specified by svchp.
src_locp (IN)
An internal LOB locator uniquely referencing the source LOB. This locator must have
been a locator that was obtained from the server specified by svchp.
Comments
Appends a LOB value at the end of another LOB as specified. The data is copied from
the source to the end of the destination. The source and destination LOBs must exist.
The destination LOB is extended to accommodate the newly written data. It is an error
to extend the destination LOB beyond the maximum length allowed (4 Gigabytes (GB))
or to try to copy from a NULL LOB.
The source and the destination LOB locators must be of the same type (that is, they
must both be BLOBs or both be CLOBs). LOB buffering must not be enabled for either
type of locator. This function does not accept a BFILE locator as the source or the
destination.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle

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LOB Functions

recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobTrim2()
Truncates the LOB value to a shorter length. This function must be used for LOBs
of size greater than 4 GB.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.4 OCILobArrayRead()
Reads LOB data for multiple locators in one round-trip.
Purpose
This function can be used for LOBs of size greater than or less than 4 GB.
Syntax
sword OCILobArrayRead ( OCISvcCtx
*svchp,
OCIError
*errhp,
ub4
*array_iter,
OCILobLocator
**locp_arr,
oraub8
*byte_amt_arr,
oraub8
*char_amt_arr,
oraub8
*offset_arr,
void
**bufp_arr,
oraub8
bufl_arr,
ub1
piece,
void
*ctxp,
OCICallbackLobArrayRead (cbfp)
(
void
*ctxp,
ub4
array_iter,
const void
*bufp,
oraub8
lenp,
ub1
piecep
void
**changed_bufpp,
oraub8
*changed_lenp
)
ub2
csid,
ub1
csfrm );

26-20

Chapter 26

LOB Functions

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
array_iter (IN/OUT)
IN - This parameter indicates the size of the LOB locator array. For polling this is
relevant only for the first call and is ignored in subsequent calls.
OUT - In polling mode, this parameter indicates the array index of the element read
from.
locp_arr (IN)
An array of LOB or BFILE locators.
byte_amt_arr (IN/OUT)
An array of oraub8 variables. The array size must be the same as the locator array
size. The entries correspond to the amount in bytes for the locators.
IN - The number of bytes to read from the database. Used for BLOB and BFILE always.
For CLOB and NCLOB, it is used only when the corresponding value in char_amt_arr is
zero.
OUT - The number of bytes read into the user buffer.
char_amt_arr (IN/OUT)
An array of oraub8 variables. The array size must be the same as the locator array
size. The entries correspond to the amount in characters for the locators.
IN - The maximum number of characters to read into the user buffer. Ignored for BLOB
and BFILE.
OUT - The number of characters read into the user buffer. Undefined for BLOB and
BFILE.
offset_arr (IN)
An array of oraub8 variables. The array size must be the same as the locator array
size. For character LOBs (CLOBs, NCLOBs) it is the number of characters from the
beginning of the LOB; for binary LOBs or BFILEs, it is the number of bytes. The first
position is 1.
bufp _arr (IN/OUT)
An array of pointers to buffers into which the piece is read. The array size must be the
same as the locator array size.
bufl_arr (IN)
An array of oraub8 variables indicating the buffer lengths for the buffer array. The array
size must be the same as the locator array size.
piece (IN)
OCI_ONE_PIECE - The call never assumes polling. If the amount indicated is more than

the buffer length, then the buffer is filled as much as possible.
For polling, pass OCI_FIRST_PIECE the first time and OCI_NEXT_PIECE in subsequent calls.
OCI_FIRST_PIECE should be passed while using the callback.

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ctxp (IN)
The context pointer for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece. If this is NULL, then
OCI_NEED_DATA is returned for each piece.
The callback function must return OCI_CONTINUE for the read to continue. If any other
error code is returned, the LOB read is terminated.
ctxp (IN)
The context for the callback function. Can be NULL.
array_iter (IN)
The index of the element read from.
bufp (IN/OUT)
A buffer pointer for the piece.
lenp (IN)
The length in bytes of the current piece in bufp.
piecep (IN)
Which piece: OCI_FIRST_PIECE, OCI_NEXT_PIECE, or OCI_LAST_PIECE.
changed_bufpp (OUT)
The callback function can put the address of a new buffer if it prefers to use a new
buffer for the next piece to read. The default old buffer bufp is used if this parameter is
set to NULL.
changed_lenp (OUT)
Length of the new buffer, if provided.
csid (IN)
The character set ID of the buffer data. If this value is 0, then csid is set to the client's
NLS_LANG or NLS_CHAR value, depending on the value of csfrm. It is never assumed to be
the server character set, unless the server and client have the same settings.
csfrm (IN)
The character set form of the buffer data. The csfrm parameter must be consistent
with the type of the LOB.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT. If csfrm is not specified, the default is assumed.
Comments
It is an error to try to read from a NULL LOB or BFILE.

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Chapter 26

LOB Functions

Note:
When reading or writing LOBs, the character set form (csfrm) specified
should match the form of the locator itself.
OCILobArrayRead() throws an error when a remote locator is passed to it.

For BFILEs, the operating system file must exist on the server, and it must have been
opened by OCILobFileOpen() or OCILobOpen() using the input locator. The Oracle
Database must have permission to read the operating system file, and the user must
have read permission on the directory object.
When you use the polling mode for OCILobArrayRead(), the first call must specify values
for offset_arr and amt_arr, but on subsequent polling calls to OCILobArrayRead(), you
need not specify these values.
If the LOB is a BLOB, the csid and csfrm parameters are ignored.

Note:
To terminate an OCILobArrayRead() operation and free the statement handle,
use the OCIBreak() call.

The following points apply to reading LOB data in streaming mode:
•

When you use polling mode, be sure to specify the char_amt_arr and byte_amt_arr
and offset_arr parameters only in the first call to OCILobArrayRead(). On
subsequent polling calls, these parameters are ignored. If both byte_amt_arr and
char_amt_arr are set to point to zero and OCI_FIRST_PIECE is passed, then polling
mode is assumed and data is read to the end of the LOB. On output, byte_amt_arr
gives the number of bytes read in the current piece. For CLOBs and NCLOBs,
char_amt_arr gives the number of characters read in the current piece.

•

When you use callbacks, the lenp parameter, which is input to the callback,
indicates how many bytes are filled in the buffer. Check the lenp parameter during
your callback processing, because the entire buffer may not be filled with data.

•

When you use polling, examine the byte_amt_arr parameter to see how much the
buffer is filled for the current piece. For CLOBs and NCLOBs, char_amt_arr returns the
number of characters read in the buffer as well.

To read data in UTF-16 format, set the csid parameter to OCI_UTF16ID. If the csid
parameter is set, it overrides the NLS_LANG environment variable.
Related Topics
•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

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Chapter 26

LOB Functions

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobFileSetName()
Sets the directory object and file name in the BFILE locator.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCILobArrayWrite()

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

PL/SQL REF CURSORs and Nested Tables in OCI for additional
information on Unicode format

•

Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

•

The demonstration programs included with your Oracle Database
installation for a code sample showing the use of LOB reads and writes.

•

OCI Demonstration Programs

•

Runtime Data Allocation and Piecewise Operations in OCI for general
information about piecewise OCI operations

26.3.5 OCILobArrayWrite()
Purpose
Writes LOB data for multiple locators in one round-trip. This function can be used for
LOBs of size greater than or less than 4 GB.
Syntax
sword OCILobArrayWrite ( OCISvcCtx
*svchp,
OCIError
*errhp,
ub4
*array_iter,
OCILobLocator
**locp_arr,
oraub8
*byte_amt_arr,
oraub8
*char_amt_arr,
oraub8
*offset_arr,
void
**bufp_arr,
oraub8
*bufl_arr,
ub1
piece,
void
*ctxp,
OCICallbackLobArrayWrite (cbfp)
(
void
*ctxp,
ub4
array_iter,
void
*bufp,
oraub8 *lenp,

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Chapter 26

LOB Functions

ub1
*piecep
void
**changed_bufpp,
oraub8 *changed_lenp
)
ub2
ub1

csid,
csfrm );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
array_iter (IN/OUT)
IN - This parameter indicates the size of the LOB locator array. For polling this is
relevant only for the first call and is ignored in subsequent calls.
OUT - In polling mode this parameter indicates the array index of the element just
written to.
locp_arr (IN/OUT)
An array of LOB locators.
byte_amt_arr (IN/OUT)
An array of pointers to oraub8 variables. The array size must be the same as the
locator array size. The entries correspond to the amount in bytes for the locators.
IN - The number of bytes to write to the database. Always used for BLOB. For CLOB and
NCLOB it is used only when char_amt_arr is zero.
OUT - The number of bytes written to the database.
char_amt (IN/OUT)
An array of pointers to oraub8 variables. The array size must be the same as the
locator array size. The entries correspond to the amount in characters for the locators.
IN - The maximum number of characters to write to the database. Ignored for BLOB.
OUT - The number of characters written to the database. Undefined for BLOB.
offset_arr (IN)
An array of pointers to oraub8 variables. The array size must be the same as the
locator array size. Each entry in the array is the absolute offset from the beginning of
the LOB value. For character LOBs (CLOBs, NCLOBs), it is the number of characters from
the beginning of the LOB; for BLOBs, it is the number of bytes. The first position is 1.
bufp_arr (IN/OUT)
An array of pointers to buffers into which the pieces for the locators are written. The
array size must be the same as the locator array size.
bufl_arr (IN)
An array of oraub8 variables indicating the buffer lengths for the buffer array. The array
size must be the same as the locator array size.

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Note:
This parameter assumes an 8-bit byte. If your operating system uses a
longer byte, you must adjust the value of bufl_arr accordingly.
piece (IN)
Which piece of the buffer is being written. The default value for this parameter is
OCI_ONE_PIECE, indicating that the buffer is written in a single piece.
The following other values are also possible for piecewise or callback mode:
OCI_FIRST_PIECE, OCI_NEXT_PIECE, and OCI_LAST_PIECE.
ctxp (IN)
The context for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece. If this is NULL, then
OCI_NEED_DATA is returned for each piece. The callback function must return
OCI_CONTINUE for the write to continue. If any other error code is returned, the LOB
write is terminated.
The callback takes the following parameters:
ctxp (IN)
The context for the callback function. Can be NULL.
array_iter (IN)
The index of the element written to.
bufp (IN/OUT)
A buffer pointer for the piece. This is the same as the bufp passed as an input to the
OCILobArrayWrite() routine.
lenp (IN/OUT)
The length (in bytes) of the data in the buffer (IN), and the length (in bytes) of the
current piece in bufp (OUT).
piecep (OUT)
Which piece: OCI_NEXT_PIECE or OCI_LAST_PIECE.
changed_bufpp (OUT)
The callback function can put the address of a new buffer if it prefers to use a new
buffer for the next piece to read. The default old buffer bufp is used if this parameter is
set to NULL.
changed_lenp (OUT)
Length of the new buffer, if provided.
csid (IN)
The character set ID of the data in the buffer. If this value is 0, then csid is set to the
client's NLS_LANG or NLS_CHAR value, depending on the value of csfrm.
csfrm (IN)
The character set form of the buffer data. The csfrm parameter must be consistent
with the type of the LOB.
The csfrm parameter has two possible nonzero values:

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•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT.
Comments
If LOB data exists, it is overwritten with the data stored in the buffer. The buffers can
be written to the LOBs in a single piece with this call, or the buffers can be provided
piecewise using callbacks or a standard polling method.
OCILobArrayWrite() throws an error when a remote locator is passed to it.

Note:
When you read or write LOBs, specify a character set form (csfrm) that
matches the form of the locator itself.
The parameters piece, csid, and csfrm are the same for all locators of the
array.

When you use the polling mode for OCILobArrayWrite(), the first call must specify
values for offset_arr, byte_amt_arr, and char_amt_arr, but on subsequent polling calls
to OCILobArrayWrite(), you need not specify these values.
If the value of the piece parameter is OCI_FIRST_PIECE, data may need to be provided
through callbacks or polling.
If a callback function is defined in the cbfp parameter, then this callback function is
invoked to get the next piece after a piece is written to the pipe. Each piece is written
from bufp_arr. If no callback function is defined, then OCILobArrayWrite() returns the
OCI_NEED_DATA error code. The application must call OCILobArrayWrite() again to write
more pieces of the LOBs. In this mode, the buffer pointer and the length can be
different in each call if the pieces are of different sizes and from different locations.
A piece value of OCI_LAST_PIECE terminates the piecewise write, regardless of whether
the polling or callback method is used.
If the amount of data passed to the database (through either input mechanism) is less
than the amount specified by the byte_amt_arr or the char_amt_arr parameter, an
ORA-22993 error is returned.
This function is valid for internal LOBs only. BFILEs are not valid, because they are
read-only. If the LOB is a BLOB, the csid and csfrm parameters are ignored.
If both byte_amt_arr and char_amt_arr are set to point to zero amount and
OCI_FIRST_PIECE is given as input, then polling mode is assumed and data is written
until you specify OCI_LAST_PIECE. For CLOBs and NCLOBs, byte_amt_arr and char_amt_arr
return the data written by each piece in terms of number of bytes and number of
characters respectively. For BLOBs, byte_amt_arr returns the number of bytes written by
each piece, whereas char_amt_arr is undefined on output.
To write data in UTF-16 format, set the csid parameter to OCI_UTF16ID. If the csid
parameter is set, it overrides the NLS_LANG environment variable.

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It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCILobArrayRead()
Reads LOB data for multiple locators in one round-trip.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

PL/SQL REF CURSORs and Nested Tables in OCI for additional
information on Unicode format

•

The demonstration programs included with your Oracle Database
installation for a code sample showing the use of LOB reads and writes.

•

OCI Demonstration Programs

•

Runtime Data Allocation and Piecewise Operations in OCI for general
information about piecewise OCI operations

26.3.6 OCILobAssign()
Assigns one LOB or BFILE locator to another
Purpose
Assigns one LOB or BFILE locator to another.

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Syntax
sword OCILobAssign ( OCIEnv
*envhp,
OCIError
*errhp,
const OCILobLocator *src_locp,
OCILobLocator
**dst_locpp );

Parameters
envhp (IN/OUT)
OCI environment handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
src_locp (IN)
LOB or BFILE locator to copy from.
dst_locpp (IN/OUT)
LOB or BFILE locator to copy to. The caller must have allocated space for the
destination locator by calling OCIDescriptorAlloc().
Comments
Assign source locator to destination locator. After the assignment, both locators refer
to the same LOB value. For internal LOBs, the source locator's LOB value gets copied
to the destination locator's LOB value only when the destination locator gets stored in
the table. Therefore, issuing a flush of the object containing the destination locator
copies the LOB value.
OCILobAssign() throws an error when a remote locator is passed to it.
OCILobAssign() cannot be used for temporary LOBs; it generates an
OCI_INVALID_HANDLE error. For temporary LOBs, use OCILobLocatorAssign().

For BFILEs, only the locator that refers to the file is copied to the table. The operating
system file itself is not copied.
It is an error to assign a BFILE locator to an internal LOB locator, and vice versa.
If the source locator is for an internal LOB that was enabled for buffering, and the
source locator has been used to modify the LOB data through the LOB buffering
subsystem, and the buffers have not been flushed since the write, then the source
locator may not be assigned to the destination locator. This is because only one
locator for each LOB can modify the LOB data through the LOB buffering subsystem.
The value of the input destination locator must have been allocated with a call to
OCIDescriptorAlloc(). For example, assume the following declarations:
OCILobLocator
OCILobLocator

*source_loc = (OCILobLocator *) 0;
*dest_loc = (OCILobLocator *) 0;

The following code example shows how an application could allocate the source_loc
locator.
Allocating a source_loc Source Locator

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if (OCIDescriptorAlloc((void *) envhp, (void **) &source_loc,
(ub4) OCI_DTYPE_LOB, (size_t) 0, (void **) 0))
handle_error;

Assume that it then selects a LOB from a table into the source_loc to initialize it. The
application must allocate the destination locator, dest_loc, before issuing the
OCILobAssign() call to assign the value of source_loc to dest_loc, as shown in the
following code example.
Allocating a dest_loc Destination Locator
if (OCIDescriptorAlloc((void *) envhp, (void **) &dest_loc,
(ub4)OCI_DTYPE_LOB, (size_t) 0, (void **) 0))
handle_error;
if (OCILobAssign(envhp, errhp, source_loc, &dest_loc))
handle_error

Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCILobIsEqual()
Compares two LOB or BFILE locators for equality.

•

OCILobLocatorAssign()
Assigns one LOB or BFILE locator to another.

•

OCILobLocatorIsInit()
Tests to see if a given LOB or BFILE locator is initialized.

•

OCILobEnableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.7 OCILobCharSetForm()
Gets the character set form of the LOB locator, if any.
Purpose
Gets the character set form of the LOB locator, if any.
Syntax
sword OCILobCharSetForm ( OCIEnv
OCIError
const OCILobLocator
ub1

*envhp,
*errhp,
*locp,
*csfrm );

Parameters
envhp (IN/OUT)
OCI environment handle.

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errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
LOB locator for which to get the character set form.
csfrm (OUT)
Character set form of the input LOB locator. If the input locator, locp, is for a BLOB or a
BFILE, csfrm is set to 0 because there is no concept of a character set for binary
LOBs and BFILEs. The caller must allocate space for csfrm (a ub1).
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID, the default

•

SQLCS_NCHAR - NCHAR character set ID

Comments
Returns the character set form of the input CLOB or NCLOB locator in the csfrm output
parameter.
Related Topics
•

OCILobCharSetId()
Gets the LOB locator's database character set ID of the LOB locator, if any.

•

OCILobLocatorIsInit()
Tests to see if a given LOB or BFILE locator is initialized.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.8 OCILobCharSetId()
Gets the LOB locator's database character set ID of the LOB locator, if any.
Purpose
Gets the LOB locator's database character set ID of the LOB locator, if any.
Syntax
sword OCILobCharSetId ( OCIEnv
OCIError
const OCILobLocator
ub2

*envhp,
*errhp,
*locp,
*csid );

Parameters
envhp (IN/OUT)
OCI environment handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.

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locp (IN)
LOB locator for which to get the character set ID.
csid (OUT)
Database character set ID of the input LOB locator. If the input locator is for a BLOB or
a BFILE, csid is set to 0 because there is no concept of a character set for binary
LOBs or binary files. The caller must allocate space for the csid ub2.
Comments
Returns the character set ID of the input CLOB or NCLOB locator in the csid output
parameter.
Related Topics
•

OCILobCharSetForm()
Gets the character set form of the LOB locator, if any.

•

OCILobLocatorIsInit()
Tests to see if a given LOB or BFILE locator is initialized.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.9 OCILobClose()
Closes a previously opened LOB or BFILE.
Purpose
Closes a previously opened LOB or BFILE.
Syntax
sword OCILobClose ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
The LOB to close. The locator can refer to an internal or external LOB.
Comments
Closes a previously opened internal or external LOB. No error is returned if the BFILE
exists but is not opened. An error is returned if the internal LOB is not open.
Closing a LOB requires a round-trip to the server for both internal and external LOBs.
For internal LOBs, close triggers other code that relies on the close call and for
external LOBs (BFILEs), close actually closes the server-side operating system file.

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It is not mandatory that you wrap all LOB operations inside the open or close calls.
However, if you open a LOB, then you must close it before you commit your
transaction. When an internal LOB is closed, it updates the functional and domain
indexes on the LOB column. It is an error to commit the transaction before closing all
opened LOBs that were opened by the transaction.
When the error is returned, the LOB is no longer marked as open, but the transaction
is successfully committed. Hence, all the changes made to the LOB and non-LOB data
in the transaction are committed, but the domain and function-based indexing are not
updated. If this happens, rebuild your functional and domain indexes on the LOB
column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance, so if you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCILobIsOpen()
Tests whether a LOB or BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Functions for Opening and Closing LOBs
OCI provides functions to explicitly open a LOB, OCILobOpen(), to close a LOB,
OCILobClose(), and to test whether a LOB is open, OCILobIsOpen().

26.3.10 OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.
Purpose
Copies all or a portion of a LOB value into another LOB value. This function must be
used for LOBs of size greater than 4 GB. You can also use this function for LOBs
smaller than 4 GB.
Syntax
sword OCILobCopy2 ( OCISvcCtx
OCIError
OCILobLocator
OCILobLocator
oraub8
oraub8
oraub8

*svchp,
*errhp,
*dst_locp,
*src_locp,
amount,
dst_offset,
src_offset );

Parameters
svchp (IN)
The service context handle.

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errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
dst_locp (IN/OUT)
An internal LOB locator uniquely referencing the destination LOB. This locator must
have been a locator that was obtained from the server specified by svchp.
src_locp (IN)
An internal LOB locator uniquely referencing the source LOB. This locator must have
been a locator that was obtained from the server specified by svchp.
amount (IN)
The number of characters for CLOBs or NCLOBs or the number of bytes for BLOBs to be
copied from the source LOB to the destination LOB. The maximum value accepted by
this parameter is UB8MAXVAL (18446744073709551615). Specifying UB8MAXVAL also
indicates that the entire source LOB will be copied to the destination LOB using the
specified source and destination offsets.
dst_offset (IN)
This is the absolute offset for the destination LOB. For character LOBs, it is the
number of characters from the beginning of the LOB at which to begin writing. For
binary LOBs, it is the number of bytes from the beginning of the LOB from which to
begin writing. The offset starts at 1.
src_offset (IN)
This is the absolute offset for the source LOB. For character LOBs, it is the number of
characters from the beginning of the LOB. For binary LOBs, it is the number of bytes.
Starts at 1.
Comments
Copies all or a portion of an internal LOB value into another internal LOB as specified.
The data is copied from the source to the destination. The source (src_locp) and the
destination (dst_locp) LOBs must exist.
Copying a complete SecureFile in a column or partition with deduplicate enabled, to a
LOB in the same column or partition, causes the copy to be deduplicated.
If the data exists at the destination's start position, it is overwritten with the source
data. If the destination's start position is beyond the end of the current data, zero-byte
fillers (for BLOBs) or spaces (for CLOBs) are written into the destination LOB from the end
of the current data to the beginning of the newly written data from the source. The
destination LOB is extended to accommodate the newly written data if it extends
beyond the current length of the destination LOB. It is an error to extend the
destination LOB beyond the maximum length allowed (that is, 4 gigabytes) or to try to
copy from a NULL LOB. Use OCILobCopy2() for LOBs of size greater than 4 GB.
Both the source and the destination LOB locators must be of the same type (that is,
they must both be BLOBs or both be CLOBs). LOB buffering must not be enabled for
either locator.
This function does not accept a BFILE locator as the source or the destination.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you

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commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.

Note:
You can call OCILobGetLength2() to determine the length of the source
LOB.

Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.11 OCILobCreateTemporary()
Creates a temporary LOB.
Purpose
Creates a temporary LOB.
Syntax
sword OCILobCreateTemporary(OCISvcCtx
OCIError
OCILobLocator
ub2
ub1
ub1
boolean
OCIDuration

*svchp,
*errhp,
*locp,
csid,
csfrm,
lobtype,
cache,
duration);

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Parameters
svchp (IN)
The OCI service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
A locator that points to the temporary LOB. You must allocate the locator using
OCIDescriptorAlloc() before passing it to this function. It does not matter whether this
locator points to a LOB; the temporary LOB gets overwritten either way.
csid (IN)
The LOB character set ID. For Oracle8i or later, pass as OCI_DEFAULT.
csfrm (IN)
The LOB character set form of the buffer data. The csfrm parameter has two possible
nonzero values:
•

SQLCS_IMPLICIT - Database character set ID, to create a CLOB. OCI_DEFAULT can also
be used to implicitly create a CLOB.

•

SQLCS_NCHAR - NCHAR character set ID, to create an NCLOB.

The default value is SQLCS_IMPLICIT.
lobtype (IN)
The type of LOB to create. Valid values include:
•

OCI_TEMP_BLOB - For a temporary BLOB

•

OCI_TEMP_CLOB - For a temporary CLOB or NCLOB

cache (IN)
Pass TRUE if the temporary LOB should be read into the cache; pass FALSE if it should
not. The default is FALSE for NOCACHE functionality.
duration (IN)
The duration of the temporary LOB. The following are valid values:
•

OCI_DURATION_SESSION

•

OCI_DURATION_CALL

Comments
This function creates a temporary LOB and its corresponding index in the user's
temporary tablespace.
When this function is complete, the locp parameter points to an empty temporary LOB
whose length is zero.
The lifetime of the temporary LOB is determined by the duration parameter. At the end
of its duration the temporary LOB is freed. An application can free a temporary LOB
sooner with the OCILobFreeTemporary() call.
If the LOB is a BLOB, the csid and csfrm parameters are ignored.

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Related Topics
•

OCILobFreeTemporary()
Frees a temporary LOB.

•

OCILobIsTemporary()
Tests if a locator points to a temporary LOB.

•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Temporary LOB Support for more information about temporary LOBs and
their durations

26.3.12 OCILobErase2()
Erases a specified portion of the internal LOB data starting at a specified offset.
Purpose
Erases a specified portion of the internal LOB data starting at a specified offset. This
function must be used for LOBs of size greater than 4 GB. You can also use this
function for LOBs smaller than 4 GB.
Syntax
sword OCILobErase2 ( OCISvcCtx
OCIError
OCILobLocator
oraub8
oraub8

*svchp,
*errhp,
*locp,
*amount,
offset );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator that uniquely references the LOB. This locator must have
been a locator that was obtained from the server specified by svchp.
amount (IN/OUT)
The number of characters for CLOBs or NCLOBs, or bytes for BLOBs, to erase. On IN, the
value signifies the number of characters or bytes to erase. On OUT, the value
identifies the actual number of characters or bytes erased.

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offset (IN)
Absolute offset in characters for CLOBs or NCLOBs, or bytes for BLOBs, from the beginning
of the LOB value from which to start erasing data. Starts at 1.
Comments
The actual number of characters or bytes erased is returned. For BLOBs, erasing means
that zero-byte fillers overwrite the existing LOB value. For CLOBs, erasing means that
spaces overwrite the existing LOB value.
This function is valid only for internal LOBs; BFILEs are not allowed.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.13 OCILobFileClose()
Closes a previously opened BFILE.
Purpose
Closes a previously opened BFILE.

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Syntax
sword OCILobFileClose ( OCISvcCtx
OCIError
OCILobLocator

*svchp,
*errhp,
*filep );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
filep (IN/OUT)
A pointer to a BFILE locator that refers to the BFILE to be closed.
Comments
Closes a previously opened BFILE. It is an error if this function is called for an internal
LOB. No error is returned if the BFILE exists but is not opened.
This function is only meaningful the first time it is called for a particular BFILE locator.
Subsequent calls to this function using the same BFILE locator have no effect.
Related Topics
•

OCILobClose()
Closes a previously opened LOB or BFILE.

•

OCILobFileCloseAll()
Closes all open BFILEs on a given service context.

•

OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCILobIsOpen()
Tests whether a LOB or BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

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26.3.14 OCILobFileCloseAll()
Closes all open BFILEs on a given service context.
Purpose
Closes all open BFILEs on a given service context.
Syntax
sword OCILobFileCLoseAll ( OCISvcCtx
OCIError

*svchp,
*errhp );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
Closes all open BFILEs on a given service context.
Related Topics
•

OCILobFileClose()
Closes a previously opened BFILE.

•

OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

26.3.15 OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.
Purpose
Tests to see if the BFILE exists on the server's operating system.

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Syntax
sword OCILobFileExists ( OCISvcCtx
OCIError
OCILobLocator
boolean

*svchp,
*errhp,
*filep,
*flag );

Parameters
svchp (IN)
The OCI service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
filep (IN)
Pointer to the BFILE locator that refers to the file.
flag (OUT)
Returns TRUE if the BFILE exists on the server; FALSE if it does not.
Comments
Checks to see if the BFILE exists on the server's file system. It is an error to call this
function for an internal LOB.
Related Topics
•

OCILobFileClose()
Closes a previously opened BFILE.

•

OCILobFileCloseAll()
Closes all open BFILEs on a given service context.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCILobIsOpen()
Tests whether a LOB or BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

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26.3.16 OCILobFileGetName()
Gets the BFILE locator's directory object and file name.
Purpose
Gets the BFILE locator's directory object and file name.
Syntax
sword OCILobFileGetName ( OCIEnv
OCIError
const OCILobLocator
OraText
ub2
OraText
ub2

*envhp,
*errhp,
*filep,
*dir_alias,
*d_length,
*filename,
*f_length );

Parameters
envhp (IN/OUT)
OCI environment handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
filep (IN)
BFILE locator for which to get the directory object and file name.
dir_alias (OUT)
Buffer into which the directory object name is placed. This can be in UTF-16. You
must allocate enough space for the directory object name. The maximum length for
the directory object is 30 bytes.
d_length (IN/OUT)
Serves the following purposes (can be in code point for Unicode, or bytes):
•

IN: length of the input dir_alias string

•

OUT: length of the returned dir_alias string

filename (OUT)
Buffer into which the file name is placed. You must allocate enough space for the file
name. The maximum length for the file name is 255 bytes.
f_length (IN/OUT)
Serves the following purposes (in number of bytes):
•

IN: length of the input filename buffer

•

OUT: length of the returned filename string

Comments
Returns the directory object and file name associated with this BFILE locator. The
environment handle determines whether it is in Unicode. It is an error to call this
function for an internal LOB.

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Related Topics
•

OCILobFileSetName()
Sets the directory object and file name in the BFILE locator.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

26.3.17 OCILobFileIsOpen()
Tests to see if the BFILE is open.
Purpose
Tests to see if the BFILE is open.
Syntax
sword OCILobFileIsOpen ( OCISvcCtx
OCIError
OCILobLocator
boolean

*svchp,
*errhp,
*filep,
*flag );

Parameters
svchp (IN)
The OCI service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
filep (IN)
Pointer to the BFILE locator being examined.
flag (OUT)
Returns TRUE if the BFILE was opened using this particular locator; returns FALSE if it
was not.
Comments
Checks to see if a file on the server was opened with the filep BFILE locator. It is an
error to call this function for an internal LOB.
If the input BFILE locator was never passed to the OCILobFileOpen() or OCILobOpen()
command, the file is considered not to be opened by this locator. However, a different
locator may have the file open. Openness is associated with a particular locator.

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Related Topics
•

OCILobClose()
Closes a previously opened LOB or BFILE.

•

OCILobFileCloseAll()
Closes all open BFILEs on a given service context.

•

OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.

•

OCILobFileClose()
Closes a previously opened BFILE.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCILobIsOpen()
Tests whether a LOB or BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

26.3.18 OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.
Purpose
Opens a BFILE on the file system of the server for read-only access.
Syntax
sword OCILobFileOpen ( OCISvcCtx
OCIError
OCILobLocator
ub1

*svchp,
*errhp,
*filep,
mode );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.

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filep (IN/OUT)
The BFILE to open. It is an error if the locator does not refer to a BFILE.
mode (IN)
Mode in which to open the file. The only valid mode is OCI_FILE_READONLY.
Comments
Opens a BFILE on the file system of the server. The BFILE can be opened for read-only
access. BFILEs can not be written through Oracle Database. It is an error to call this
function for an internal LOB.
This function is only meaningful the first time it is called for a particular BFILE locator.
Subsequent calls to this function using the same BFILE locator have no effect.
Related Topics
•

OCILobClose()
Closes a previously opened LOB or BFILE.

•

OCILobFileCloseAll()
Closes all open BFILEs on a given service context.

•

OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.

•

OCILobFileClose()
Closes a previously opened BFILE.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCILobIsOpen()
Tests whether a LOB or BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

26.3.19 OCILobFileSetName()
Sets the directory object and file name in the BFILE locator.
Purpose
Sets the directory object and file name in the BFILE locator.

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Syntax
sword OCILobFileSetName ( OCIEnv
OCIError
OCILobLocator
const OraText
ub2
const OraText
ub2

*envhp,
*errhp,
**filepp,
*dir_alias,
d_length,
*filename,
f_length );

Parameters
envhp (IN/OUT)
OCI environment handle. Contains the UTF-16 setting.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
filepp (IN/OUT)
Pointer to the BFILE locator for which to set the directory object and file name.
dir_alias (IN)
Buffer that contains the directory object name (must be in the encoding specified by
the charset parameter of a previous call to OCIEnvNlsCreate() to set in the BFILE
locator.
d_length (IN)
Length (in bytes) of the input dir_alias parameter.
filename (IN)
Buffer that contains the file name (must be in the encoding specified by the charset
parameter of a previous call to OCIEnvNlsCreate() to set in the BFILE locator.
f_length (IN)
Length (in bytes) of the input filename parameter.
Comments
It is an error to call this function for an internal LOB.
Related Topics
•

OCILobFileGetName()
Gets the BFILE locator's directory object and file name.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

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26.3.20 OCILobFreeTemporary()
Frees a temporary LOB.
Purpose
Frees a temporary LOB.
Syntax
sword OCILobFreeTemporary( OCISvcCtx
OCIError
OCILobLocator

*svchp,
*errhp,
*locp);

Parameters
svchp (IN/OUT)
The OCI service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
A locator uniquely referencing the LOB to be freed.
Comments
This function frees the contents of the temporary LOB to which this locator points.
Note that the locator itself is not freed until OCIDescriptorFree() is called. You must
always call OCILobFreeTemporary() before calling OCIDescriptorFree() or
OCIArrayDescriptorFree() to free the contents of the temporary LOB. See About
Freeing Temporary LOBs for more information.
This function returns an error if the LOB locator passed in the locp parameter does not
point to a temporary LOB, possibly because the LOB locator:
•

Points to a permanent LOB

•

Pointed to a temporary LOB that has been freed

•

Has never pointed to anything

Related Topics
•

OCILobCreateTemporary()
Creates a temporary LOB.

•

OCILobIsTemporary()
Tests if a locator points to a temporary LOB.

•

OCIDescriptorFree()
Deallocates a previously allocated descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.3.21 OCILobGetChunkSize()
Gets the chunk size of a LOB.
Purpose
Gets the chunk size of a LOB.
Syntax
sword OCILobGetChunkSize ( OCISvcCtx
OCIError
OCILobLocator
ub4

*svchp,
*errhp,
*locp,
*chunk_size );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
The internal LOB for which to get the usable chunk size.
chunk_size (OUT)
For LOBs with storage parameter BASICFILE, the amount of a chunk's space that is
used to store the internal LOB value. This is the amount that users should use when
reading or writing the LOB value. If possible, users should start their writes at chunk
boundaries, such as the beginning of a chunk, and write a chunk at a time.
The chunk_size parameter is returned in terms of bytes for BLOBs, CLOBs, and NCLOBs.
For LOBs with storage parameter SECUREFILE, chunk_size is an advisory size and is
provided for backward compatibility.
Comments
When creating a table that contains an internal LOB, the user can specify the chunking
factor, which can be a multiple of Oracle Database blocks. This corresponds to the
chunk size used by the LOB data layer when accessing and modifying the LOB value.
Part of the chunk is used to store system-related information, and the rest stores the
LOB value. This function returns the amount of space used in the LOB chunk to store
the LOB value. Performance is improved if the application issues read or write
requests using a multiple of this chunk size. For writes, there is an added benefit
because LOB chunks are versioned and, if all writes are done on a chunk basis, no
extra versioning is done or duplicated. Users could batch up the write until they have
enough for a chunk instead of issuing several write calls for the same chunk.
Related Topics
•

OCILobGetStorageLimit()
Gets the maximum length of an internal LOB (BLOB, CLOB, or NCLOB) in bytes.

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•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
About Improving LOB Read/Write Performance

26.3.22 OCILobGetContentType()
Gets the user-specified content type string for the data in a SecureFile, if set.
Purpose
Gets the user-specified content type string for the data in a SecureFile, if set.
Syntax
sword OCILobGetContentType ( OCIEnv
OCISvcCtx
OCIError
OCILobLocator
oratext
ub4
ub4

*envhp,
*svchp,
*errhp,
*lobp,
*contenttypep,
*contenttypelenp,
mode );

Parameters
envhp (IN)
The environment handle.
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet() for diagnostic information when
there is an error.

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lobp (IN)
A LOB locator that uniquely references a LOB.
contenttypep (IN/OUT)
Pointer to the buffer where the content type is stored after successful execution. You
must allocate the buffer before calling this function. The size of the allocated buffer
must be >= OCI_LOB_CONTENTTYPE_MAXSIZE.
contenttypelenp (IN/OUT)
Set this field to the size of contenttypep buffer. After the call successfully executes,
this field holds the size of the contenttypep returned.
mode (IN)
For future use. Pass zero now.
Comments
This function only works on SecureFiles. If lobp is not a SecureFile, then the error
SECUREFILE_WRONGTYPE is returned. If lobp is buffered, a temporary LOB, or an abstract
LOB, then the error SECUREFILE_BADLOB is returned.
If the SecureFile does not have a contenttype associated with it, the contenttype length
(contenttypelenp) is returned as 0 without modifying the buffer contenttypep.
The maximum possible size of the ContentType string is defined as:
#define OCI_LOB_CONTENTTYPE_MAXSIZE 128

The ContentType is ASCII (that is, 1-byte/7-bit UTF8).
Related Topics
•

OCILobSetContentType()
Sets a content type string for the data in the SecureFile to something that can be
used by an application.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.23 OCILobGetLength2()
Gets the length of a LOB. This function must be used for LOBs of size greater than 4
GB.
Purpose
You can also use this function for LOBs smaller than 4 GB.
Syntax
sword OCILobGetLength2 ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp,
oraub8
*lenp );

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Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
A LOB locator that uniquely references the LOB. For internal LOBs, this locator must
have been a locator that was obtained from the server specified by svchp. For BFILEs,
the locator can be set by OCILobFileSetName(), by a SELECT statement, or by
OCIObjectPin().
lenp (OUT)
On output, it is the length of the LOB if the LOB is not NULL. For character LOBs, it is
the number of characters; for binary LOBs and BFILEs, it is the number of bytes in the
LOB.
Comments
Gets the length of a LOB. If the LOB is NULL, the length is undefined. The length of a
BFILE includes the EOF, if it exists. The length of an empty internal LOB is zero.
Regardless of whether the client-side character set is varying-width, the output length
is in characters for CLOBs and NCLOBs, and in bytes for BLOBs and BFILEs.

Note:
Any zero-byte or space fillers in the LOB written by previous calls to
OCILobErase2() or OCILobWrite2() are also included in the length count.

Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCILobFileSetName()
Sets the directory object and file name in the BFILE locator.

•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

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•

OCILobLoadFromFile2()
Loads and copies all or a portion of the file into an internal LOB. This function must
be used for LOBs of size greater than 4 GB.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.24 OCILobGetOptions()
Obtains the enabled settings corresponding to the given input option types for a given
SecureFile LOB.
Purpose
Obtains the enabled settings corresponding to the given input option types for a given
SecureFile LOB.
Syntax
sword OCILobGetOptions ( OCISvcCtx
OCIError
OCILobLocator
ub4
void
ub4
ub4

*svchp,
*errhp,
*locp,
option_types,
*optionsp,
optionslenp,
mode );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
The LOB locator or BFILE locator that uniquely references the LOB or BFILE. This
locator must have been obtained from the server specified by svchp.
option_types (IN)
The given option types that can be combined by a bit-wise inclusive OR (symbol "|"):
•

Compression - OCI_LOB_OPT_COMPRESS

•

Encryption - OCI_LOB_OPT_ENCRYPT

•

Deduplication - OCI_LOB_OPT_DEDUPLICATE

optionsp (OUT)
The current settings for each of the option types given. Possible values are:
•

OCI_LOB_OPT_COMPRESS_ON

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•

OCI_LOB_OPT_ENCRYPT_ON

•

OCI_LOB_OPT_DEDUPLICATE_ON

optionslenp (OUT)
The length of the value in optionsp.
mode (IN)
Reserved for future use. Pass in 0.
Comments
You can only specify option types that have been enabled on the column. An error is
returned when an attempt is made to get the value of an option type that is not
enabled on the column. For example, if you have a LOB column with compression
enabled, and you call OCILobGetOptions() with OCI_LOB_OPT_ENCRYPT set in the
option_types parameter, an error occurs.
Note that the returned value is a ub4 pointer cast as a void pointer to allow for future
expansion of option types and values. The optionslenp returned should be equal to
sizeof(ub4).
Related Topics
•

OCILobSetOptions()
Enables option settings for a SecureFile LOB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.25 OCILobGetStorageLimit()
Gets the maximum length of an internal LOB (BLOB, CLOB, or NCLOB) in bytes.
Purpose
Gets the maximum length of an internal LOB (BLOB, CLOB, or NCLOB) in bytes.
Syntax
sword OCILobGetStorageLimit ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp,
oraub8
*limitp );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
A LOB locator that uniquely references the LOB. The locator must have been one that
was obtained from the server specified by svchp.

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limitp (OUT)
The maximum length of the LOB (in bytes) that can be stored in the database.
Comments
Because block size ranges from 2 KB to 32 KB, the maximum LOB size ranges from 8
terabytes to 128 terabytes (TB) for LOBs.
Related Topics
•

OCILobGetChunkSize()
Gets the chunk size of a LOB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

About Using LOBs of Size Greater than 4 GB
Starting with Oracle Database 10g Release 1 of OCI, functions were introduced to
support LOBs of size greater than 4 GB. These new functions can also be used in
new applications for LOBs of less than 4 GB.

26.3.26 OCILobIsEqual()
Compares two LOB or BFILE locators for equality.
Purpose
Compares two LOB or BFILE locators for equality.
Syntax
sword OCILobIsEqual ( OCIEnv
const OCILobLocator
const OCILobLocator
boolean

*envhp,
*x,
*y,
*is_equal );

Parameters
envhp (IN)
The OCI environment handle.
x (IN)
LOB locator to compare.
y (IN)
LOB locator to compare.
is_equal (OUT)
TRUE, if the LOB locators are equal; FALSE if they are not.

Comments
Compares the given LOB or BFILE locators for equality. Two LOB or BFILE locators are
equal if and only if they both refer to the same LOB or BFILE value.
Two NULL locators are considered not equal by this function.

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Related Topics
•

OCILobAssign()
Assigns one LOB or BFILE locator to another

•

OCILobLocatorIsInit()
Tests to see if a given LOB or BFILE locator is initialized.

26.3.27 OCILobIsOpen()
Tests whether a LOB or BFILE is open.
Purpose
Tests whether a LOB or BFILE is open.
Syntax
sword OCILobIsOpen ( OCISvcCtx
OCIError
OCILobLocator
boolean

*svchp,
*errhp,
*locp,
*flag );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
Pointer to the LOB locator being examined. The locator can refer to an internal or
external LOB.
flag (OUT)
Returns TRUE if the internal LOB is open or if the BFILE was opened using the input
locator. Returns FALSE if it was not.
Comments
Checks to see if the internal LOB is open or if the BFILE was opened using the input
locator.
For BFILEs
If the input BFILE locator was never passed to OCILobOpen() or OCILobFileOpen(), the
BFILE is considered not to be opened by this BFILE locator. However, a different BFILE
locator may have opened the BFILE. Multiple opens can be performed on the same
BFILE using different locators. In other words, openness is associated with a specific
locator for BFILEs.
For internal LOBs
Openness is associated with the LOB, not with the locator. If locator1 opened the
LOB, then locator2 also sees the LOB as open.
For internal LOBs, this call requires a server round-trip because it checks the state on
the server to see if the LOB is open. For external LOBs (BFILEs), this call also requires

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a round-trip because the operating system file on the server side must be checked to
see if it is open.
Related Topics
•

OCILobClose()
Closes a previously opened LOB or BFILE.

•

OCILobFileCloseAll()
Closes all open BFILEs on a given service context.

•

OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.

•

OCILobFileClose()
Closes a previously opened BFILE.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Functions for Opening and Closing LOBs
OCI provides functions to explicitly open a LOB, OCILobOpen(), to close a LOB,
OCILobClose(), and to test whether a LOB is open, OCILobIsOpen().

26.3.28 OCILobIsTemporary()
Tests if a locator points to a temporary LOB.
Purpose
Tests if a locator points to a temporary LOB.
Syntax
sword OCILobIsTemporary(OCIEnv
OCIError
OCILobLocator
boolean

*envhp,
*errhp,
*locp,
*is_temporary);

Parameters
envhp (IN)
The OCI environment handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
The locator to test.

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is_temporary (OUT)
Returns TRUE if the LOB locator points to a temporary LOB; FALSE if it does not.
Comments
This function tests a locator to determine if it points to a temporary LOB. If so,
is_temporary is set to TRUE. If not, is_temporary is set to FALSE.

Related Topics
•

OCILobCreateTemporary()
Creates a temporary LOB.

•

OCILobFreeTemporary()
Frees a temporary LOB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.29 OCILobLoadFromFile2()
Loads and copies all or a portion of the file into an internal LOB. This function must be
used for LOBs of size greater than 4 GB.
Purpose
You can also use this function for LOBs smaller than 4 GB.
Syntax
sword OCILobLoadFromFile2 ( OCISvcCtx
OCIError
OCILobLocator
OCILobLocator
oraub8
oraub8
oraub8

*svchp,
*errhp,
*dst_locp,
*src_locp,
amount,
dst_offset,
src_offset );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
dst_locp (IN/OUT)
A locator uniquely referencing the destination internal LOB, that may be of type BLOB,
CLOB, or NCLOB.
src_locp (IN/OUT)
A locator uniquely referencing the source BFILE.
amount (IN)
The number of bytes to be loaded.

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dst_offset (IN)
This is the absolute offset for the destination LOB. For character LOBs, it is the
number of characters from the beginning of the LOB at which to begin writing. For
binary LOBs, it is the number of bytes from the beginning of the LOB from which to
begin reading. The offset starts at 1.
src_offset (IN)
This is the absolute offset for the source BFILE. It is the number of bytes from the
beginning of the BFILE. The offset starts at 1.
Comments
Loads and copies a portion or all of a BFILE value into an internal LOB as specified.
The data is copied from the source BFILE to the destination internal LOB (BLOB or CLOB).
No character set conversions are performed when copying the BFILE data to a CLOB or
NCLOB. Also, when binary data is loaded into a BLOB, no character set conversions are
performed. Therefore, the BFILE data must be in the same character set as the LOB in
the database. No error checking is performed to verify this.
OCILobLoadFromFile2() throws an error when a remote locator is passed to it.

The source (src_locp) and the destination (dst_locp) LOBs must exist. If the data
exists at the destination's start position, it is overwritten with the source data. If the
destination's start position is beyond the end of the current data, zero-byte fillers (for
BLOBs) or spaces (for CLOBs) are written into the destination LOB from the end of the
data to the beginning of the newly written data from the source. The destination LOB is
extended to accommodate the newly written data if it extends beyond the current
length of the destination LOB.
It is an error to extend the destination LOB beyond the maximum length allowed (4
gigabytes) (see OCILobLoadFromFile2() to use for LOBs of size greater than 4 GB) or to
try to copy from a NULL BFILE.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobTrim2()
Truncates the LOB value to a shorter length. This function must be used for LOBs
of size greater than 4 GB.

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•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobGetLength2()
Gets the length of a LOB. This function must be used for LOBs of size greater than
4 GB.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.30 OCILobLocatorAssign()
Assigns one LOB or BFILE locator to another.
Purpose
Assigns one LOB or BFILE locator to another.
Syntax
sword OCILobLocatorAssign ( OCISvcCtx
OCIError
const OCILobLocator
OCILobLocator

*svchp,
*errhp,
*src_locp,
**dst_locpp );

Parameters
svchp (IN/OUT)
The OCI service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
src_locp (IN)
The LOB or BFILE locator to copy from.
dst_locpp (IN/OUT)
The LOB or BFILE locator to copy to. The caller must allocate space for the
OCILobLocator by calling OCIDescriptorAlloc().
Comments
This call assigns the source locator to the destination locator. After the assignment,
both locators refer to the same LOB data. For internal LOBs, the source locator's LOB
data gets copied to the destination locator's LOB data only when the destination
locator gets stored in the table. Therefore, issuing a flush of the object containing the
destination locator copies the LOB data. For BFILEs, only the locator that refers to the
operating system file is copied to the table; the operating system file is not copied.
OCILobLocatorAssign() throws an error when a remote locator is passed to it.

Note that this call is similar to OCILobAssign(), but OCILobLocatorAssign() takes an OCI
service handle pointer instead of an OCI environment handle pointer. Also,

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OCILobLocatorAssign() can be used for temporary LOBs, but OCILobAssign() cannot be

used for temporary LOBs.

Note:
If the OCILobLocatorAssign() function fails, the target locator is not restored to
its previous state. The target locator should not be used in subsequent
operations unless it is reinitialized.

If the destination locator is for a temporary LOB, the destination temporary LOB is
freed before the source LOB locator is assigned to it.
If the source LOB locator refers to a temporary LOB, the destination is made into a
temporary LOB too. The source and the destination are conceptually different
temporary LOBs. In the OCI_DEFAULT mode, the source temporary LOB is deep copied,
and a destination locator is created to refer to the new deep copy of the temporary
LOB. Hence OCILobIsEqual() returns FALSE after the OCILobLocatorAssign() call.
However, in the OCI_OBJECT mode, an optimization is made to minimize the number of
deep copies, so the source and destination locators point to the same LOB until any
modification is made through either LOB locator. Hence OCILobIsEqual() returns TRUE
right after OCILobLocatorAssign() until the first modification. In both these cases, after
the OCILobLocatorAssign(), any changes to the source or the destination do not reflect
in the other (that is, destination or source) LOB. If you want the source and the
destination to point to the same LOB and want your changes to reflect in the other,
then you must use the equal sign to ensure that the two LOB locator pointers refer to
the same LOB locator.
Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCILobAssign()
Assigns one LOB or BFILE locator to another

•

OCILobIsEqual()
Compares two LOB or BFILE locators for equality.

•

OCILobLocatorIsInit()
Tests to see if a given LOB or BFILE locator is initialized.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.31 OCILobLocatorIsInit()
Tests to see if a given LOB or BFILE locator is initialized.
Purpose
Tests to see if a given LOB or BFILE locator is initialized.
Syntax
sword OCILobLocatorIsInit ( OCIEnv
OCIError

*envhp,
*errhp,

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const OCILobLocator *locp,
boolean
*is_initialized );

Parameters
envhp (IN/OUT)
OCI environment handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
The LOB or BFILE locator being tested.
is_initialized (OUT)
Returns TRUE if the given LOB or BFILE locator is initialized; returns FALSE if it is not.
Comments
Tests to see if a given LOB or BFILE locator is initialized.
Internal LOB locators can be initialized by one of these methods:
•

Selecting a non-NULL LOB into the locator

•

Pinning an object that contains a non-NULL LOB attribute by OCIObjectPin()

•

Setting the locator to empty by OCIAttrSet()

See Also:
LOB Descriptor and LOB Locator Attributes
BFILE locators can be initialized by one of these methods:

•

Selecting a non-NULL BFILE into the locator

•

Pinning an object that contains a non-NULL BFILE attribute by OCIObjectPin()

•

Calling OCILobFileSetName()

Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCILobIsEqual()
Compares two LOB or BFILE locators for equality.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.3.32 OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.
Purpose
Opens a LOB, internal or external, in the indicated mode.
Syntax
sword OCILobOpen ( OCISvcCtx
OCIError
OCILobLocator
ub1

*svchp,
*errhp,
*locp,
mode );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
The LOB to open. The locator can refer to an internal or external LOB.
mode (IN)
The mode in which to open the LOB or BFILE. In Oracle8i or later, valid modes for
LOBs are OCI_LOB_READONLY and OCI_LOB_READWRITE. Note that OCI_FILE_READONLY exists
as input to OCILobFileOpen(). OCI_FILE_READONLY can be used with OCILobOpen() if the
input locator is for a BFILE.
Comments
It is an error to open the same LOB twice. BFILEs cannot be opened in read/write
mode. If a user tries to write to a LOB or BFILE that was opened in read-only mode, an
error is returned.
Opening a LOB requires a round-trip to the server for both internal and external LOBs.
For internal LOBs, the open triggers other code that relies on the open call. For
external LOBs (BFILEs), open requires a round-trip because the actual operating
system file on the server side is being opened.
It is not necessary to open a LOB to perform operations on it. When using functionbased indexes, extensible indexes or context, and making multiple calls to update or
write to the LOB, you should first call OCILobOpen(), then update the LOB as many
times as you want, and finally call OCILobClose(). This sequence of operations ensures
that the indexes are only updated once at the end of all the write operations instead of
once for each write operation.
It is not mandatory that you wrap all LOB operations inside the open and close calls.
However, if you open a LOB, then you must close it before you commit your
transaction. When an internal LOB is closed, it updates the functional and domain
indexes on the LOB column. It is an error to commit the transaction before closing all
opened LOBs that were opened by the transaction.

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When the error is returned, the LOB is no longer marked as open, but the transaction
is successfully committed. Hence, all the changes made to the LOB and non-LOB data
in the transaction are committed, but the domain and function-based indexing are not
updated. If this happens, rebuild your functional and domain indexes on the LOB
column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance, so if you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobClose()
Closes a previously opened LOB or BFILE.

•

OCILobFileCloseAll()
Closes all open BFILEs on a given service context.

•

OCILobFileExists()
Tests to see if the BFILE exists on the server's operating system.

•

OCILobFileClose()
Closes a previously opened BFILE.

•

OCILobFileIsOpen()
Tests to see if the BFILE is open.

•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobIsOpen()
Tests whether a LOB or BFILE is open.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Functions for Opening and Closing LOBs
OCI provides functions to explicitly open a LOB, OCILobOpen(), to close a LOB,
OCILobClose(), and to test whether a LOB is open, OCILobIsOpen().

26.3.33 OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This function
must be used for LOBs of size greater than 4 GB.
Purpose
You can also use this function for LOBs smaller than 4 GB.
Syntax
sword OCILobRead2 ( OCISvcCtx
OCIError
OCILobLocator
oraub8
oraub8
oraub8
void
oraub8

*svchp,
*errhp,
*locp,
*byte_amtp,
*char_amtp,
offset,
*bufp,
bufl,

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ub1
piece,
void
*ctxp,
OCICallbackLobRead2 (cbfp)
( void
const void
oraub8
ub1
void
oraub8
)
ub2
csid,
ub1
csfrm );

*ctxp,
*bufp,
lenp,
piecep
**changed_bufpp,
*changed_lenp

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
A LOB or BFILE locator that uniquely references the LOB or BFILE. This locator must
have been a locator that was obtained from the server specified by svchp.
byte_amtp (IN/OUT)
IN - The number of bytes to read from the database. Used for BLOB and BFILE always.
For CLOB and NCLOB, it is used only when char_amtp is zero.
OUT - The number of bytes read into the user buffer.
char_amtp (IN/OUT)
IN - The maximum number of characters to read into the user buffer. Ignored for BLOB
and BFILE.
OUT - The number of characters read into the user buffer. Undefined for BLOB and
BFILE.
offset (IN)
On input, this is the absolute offset from the beginning of the LOB value. For
character LOBs (CLOBs, NCLOBs), it is the number of characters from the beginning of
the LOB; for binary LOBs or BFILEs, it is the number of bytes. The first position is 1.
If you use streaming (by polling or a callback), specify the offset in the first call; in
subsequent polling calls, the offset parameter is ignored. When you use a callback,
there is no offset parameter.
bufp (IN/OUT)
The pointer to a buffer into which the piece is read. The length of the allocated
memory is assumed to be bufl.
bufl (IN)
The length of the buffer in octets. This value differs from the amtp value for CLOBs and
for NCLOBs (csfrm=SQLCS_NCHAR) when the amtp parameter is specified in terms of
characters, and the bufl parameter is specified in terms of bytes.
piece (IN)
OCI_ONE_PIECE - The call never assumes polling. If the amount indicated is more than

the buffer length, then the buffer is filled as much as possible.

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For polling, pass OCI_FIRST_PIECE the first time and OCI_NEXT_PIECE in subsequent calls.
OCI_FIRST_PIECE should be passed while using the callback.
ctxp (IN)
The context pointer for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece. If this is NULL, then
OCI_NEED_DATA is returned for each piece.
The callback function must return OCI_CONTINUE for the read to continue. If any other
error code is returned, the LOB read is terminated.
ctxp (IN)
The context for the callback function. Can be NULL.
bufp (IN/OUT)
A buffer pointer for the piece.
lenp (IN)
The length in bytes of the current piece in bufp.
piecep (IN)
Which piece: OCI_FIRST_PIECE, OCI_NEXT_PIECE, or OCI_LAST_PIECE.
changed_bufpp (OUT)
The callback function can put the address of a new buffer if it prefers to use a new
buffer for the next piece to read. The default old buffer bufp is used if this parameter is
set to NULL.
changed_lenp (OUT)
Length of the new buffer, if provided.
csid (IN)
The character set ID of the buffer data. If this value is 0, then csid is set to the client's
NLS_LANG or NLS_CHAR value, depending on the value of csfrm. It is never assumed to be
the server character set, unless the server and client have the same settings.
csfrm (IN)
The character set form of the buffer data. The csfrm parameter must be consistent
with the type of the LOB.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT. If csfrm is not specified, the default is assumed.
Comments
Reads a portion of a LOB or BFILE as specified by the call into a buffer. It is an error to
try to read from a NULL LOB or BFILE.

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Note:
When you read or write LOBs, specify a character set form (csfrm) that
matches the form of the locator itself.

For BFILEs, the operating system file must exist on the server, and it must have been
opened by OCILobFileOpen() or OCILobOpen() using the input locator. Oracle Database
must have permission to read the operating system file, and the user must have read
permission on the directory object.
When you use the polling mode for OCILobRead2(), the first call must specify values for
offset and amtp, but on subsequent polling calls to OCILobRead2(), you need not specify
these values.
If the LOB is a BLOB, the csid and csfrm parameters are ignored.

Note:
To terminate an OCILobRead2() operation and free the statement handle, use
the OCIBreak() call.

The following points apply to reading LOB data in streaming mode:
•

When you use polling mode, be sure to specify the char_amtp and byte_amtp and
offset parameters only in the first call to OCILobRead2(). On subsequent polling calls
these parameters are ignored. If both byte_amtp and char_amtp are set to point to
zero and OCI_FIRST_PIECE is passed, then polling mode is assumed and data is
read till the end of the LOB. On output, byte_amtp gives the number of bytes read
in the current piece.
For CLOBs and NCLOBs, char_amtp gives the number of characters read in the current
piece.
For CLOBs and NCLOBs, if you do not pass char_amtp, then char_amtp is calculated
internally as byte_amtp/max char width, so if max char width is 4, char_amtp is
calculated as byte_amtp/4. Thus, OCILobRead2() does not calculate how many bytes
are required for each character. Instead, OCILobRead2() fetches in the worst case
the number of characters that can fit in byte_amtp. To fill the buffer, check the
byte_amtp parameter to see how much of the buffer is filled, then call OCILobRead2()
again to fetch the remaining bytes.

•

When you use callbacks, the len parameter, which is input to the callback,
indicates how many bytes are filled in the buffer. Check the len parameter during
your callback processing, because the entire buffer cannot be filled with data.

•

When you use polling, look at the byte_amtp parameter to see how much the buffer
is filled for the current piece. For CLOBs and NCLOBs, char_amtp returns the number of
characters read in the buffer as well.

To read data in UTF-16 format, set the csid parameter to OCI_UTF16ID. If the csid
parameter is set, it overrides the NLS_LANG environment variable.

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Related Topics
•

OCILobFileOpen()
Opens a BFILE on the file system of the server for read-only access.

•

OCILobOpen()
Opens a LOB, internal or external, in the indicated mode.

•

OCIBreak()
Performs an immediate asynchronous break.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobFileSetName()
Sets the directory object and file name in the BFILE locator.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

PL/SQL REF CURSORs and Nested Tables in OCI for additional
information about Unicode format

•

Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

•

The demonstration programs included with your Oracle Database
installation for a code sample showing the use of LOB reads and writes.

•

OCI Demonstration Programs

•

Runtime Data Allocation and Piecewise Operations in OCI for general
information about piecewise OCI operations

•

Polling Mode Operations in OCI

26.3.34 OCILobSetContentType()
Sets a content type string for the data in the SecureFile to something that can be used
by an application.
Purpose
Sets a content type string for the data in the SecureFile to something that can be used
by an application.
Syntax
sword OCILobSetContentType ( OCIEnv
OCISvcCtx
OCIError
OCILobLocator

*envhp,
*svchp,
*errhp,
*lobp,

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const oratext *contenttypep,
ub4
contenttypelen,
ub4
mode);

Parameters
envhp (IN)
The environment handle.
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that can be passed to OCIErrorGet() for diagnostic information when
there is an error.
lobp (IN)
A LOB locator that uniquely references a LOB.
contenttypep (IN)
The contenttype to be set for the given LOB.
contenttypelen (IN)
The size of contenttype in bytes. The size must be less than or equal to
OCI_LOB_CONTENTTYPE_MAXSIZE bytes.
mode (IN)
For future use. Pass zero now.
Comments
This function only works on SecureFiles. If lobp is not a SecureFile, then the error
SECUREFILE_WRONGTYPE is returned. If lobp is buffered, a temporary LOB, or an abstract
LOB, then the error SECUREFILE_BADLOB is returned.
The maximum possible size of the ContentType string is defined as:
#define OCI_LOB_CONTENTTYPE_MAXSIZE 128

The ContentType is ASCII (that is, 1-byte/7-bit UTF8).
To clear an existing contenttype set on a SecureFile, invoke OCILobSetContentType()
with contenttypep set to (oratext *)0 and contenttypelen set to 0.
Related Topics
•

OCILobGetContentType()
Gets the user-specified content type string for the data in a SecureFile, if set.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.35 OCILobSetOptions()
Enables option settings for a SecureFile LOB.
Purpose
Enables option settings for a SecureFile LOB.

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Syntax
sword OCILobSetOptions ( OCISvcCtx
OCIError
OCILobLocator
ub4
void
ub4
ub4

*svchp,
*errhp,
*locp,
option_types,
*optionsp,
optionslen,
mode );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
The LOB locator that uniquely references the LOB. This locator must have been a
locator that was obtained from the server specified by svchp.
option_types (IN)
You can specify multiple option types and values by using the bit-wise inclusive OR
("|"). An error results if you specify an option_types value that is not enabled on the
LOB column.
•

Compression —OCI_LOB_OPT_COMPRESS

•

Encryption — OCI_LOB_OPT_ENCRYPT

•

Deduplication —OCI_LOB_OPT_DEDUPLICATE

•

Allocation size — OCI_LOB_OPT_ALLOCSIZE

•

Content type — OCI_LOB_OPT_CONTENTTYPE

•

Modification time — OCI_LOB_OPT_MODTIME

optionsp (IN)
The possible settings are:
•

OCI_LOB_OPT_COMPRESS_OFF

•

OCI_LOB_OPT_COMPRESS_ON

•

OCI_LOB_ENCRYPT_OFF

•

OCI_LOB_ENCRYPT_ON

•

OCI_LOB_OPT_DEDUPLICATE_OFF

•

OCI_LOB_OPT_DEDUPLICATE_ON

optionslen (IN)
The length of the value in optionsp. Note that the only valid length at this time is
sizeof(ub4).
mode (IN)
Reserved for future use. Pass in 0.

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Related Topics
•

OCILobGetOptions()
Obtains the enabled settings corresponding to the given input option types for a
given SecureFile LOB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.36 OCILobTrim2()
Truncates the LOB value to a shorter length. This function must be used for LOBs of
size greater than 4 GB.
Purpose
You can also use this function for LOBs smaller than 4 GB.
Syntax
sword OCILobTrim2 ( OCISvcCtx
OCIError
OCILobLocator
oraub8

*svchp,
*errhp,
*locp,
newlen );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator that uniquely references the LOB. This locator must have
been a locator that was obtained from the server specified by svchp.
newlen (IN)
The new length of the LOB value, which must be less than or equal to the current
length. For character LOBs, it is the number of characters; for binary LOBs and
BFILEs, it is the number of bytes in the LOB.
Comments
This function trims the LOB data to a specified shorter length. The function returns an
error if newlen is greater than the current LOB length. This function is valid only for
internal LOBs. BFILEs are not allowed.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can

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adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobErase2()
Erases a specified portion of the internal LOB data starting at a specified offset.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.3.37 OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater than 4
GB.
Purpose
You can also use this function for LOBs smaller than 4 GB.
Syntax
sword OCILobWrite2 ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp,
oraub8
*byte_amtp,
oraub8
*char_amtp,
oraub8
offset,
void
*bufp,
oraub8
buflen,
ub1
piece,
void
*ctxp,
OCICallbackLobWrite2 (cbfp)
(
void
*ctxp,
void
*bufp,
oraub8 *lenp,
ub1
*piecep
void
**changed_bufpp,
oraub8 *changed_lenp
)

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ub2
ub1

csid,
csfrm );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator that uniquely references the LOB. This locator must have
been a locator that was obtained from the server specified by svchp.
byte_amtp (IN/OUT)
IN - The number of bytes to write to the database. Always used for BLOB. For CLOB and
NCLOB it is used only when char_amtp is zero.
OUT - The number of bytes written to the database. In polling mode, it is the length of
the piece, in bytes, just written.
char_amtp (IN/OUT)
IN - The maximum number of characters to write to the database. Ignored for BLOB.
OUT - The number of characters written to the database. Undefined for BLOB. In polling
mode, it is the length of the piece, in characters, just written.
offset (IN)
On input, it is the absolute offset from the beginning of the LOB value. For character
LOBs, it is the number of characters from the beginning of the LOB; for binary LOBs,
it is the number of bytes. The first position is 1.
If you use streaming (by polling or a callback), specify the offset in the first call; in
subsequent polling calls, the offset parameter is ignored. When you use a callback,
there is no offset parameter.
bufp (IN)
The pointer to a buffer from which the piece is written. The length of the data in the
buffer is assumed to be the value passed in buflen. Even if the data is being written in
pieces using the polling method, bufp must contain the first piece of the LOB when
this call is invoked. If a callback is provided, bufp must not be used to provide data or
an error results.
buflen (IN)
The length, in bytes, of the data in the buffer. This value differs from the char_amtp
value for CLOBs and NCLOBs when the amount is specified in terms of characters using
the char_amtp parameter, and the buflen parameter is specified in terms of bytes.

Note:
This parameter assumes an 8-bit byte. If your operating system uses a
longer byte, you must adjust the value of buflen accordingly.

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piece (IN)
Which piece of the buffer is being written. The default value for this parameter is
OCI_ONE_PIECE, indicating that the buffer is written in a single piece.
The following other values are also possible for piecewise or callback mode:
OCI_FIRST_PIECE, OCI_NEXT_PIECE, and OCI_LAST_PIECE.
ctxp (IN)
The context for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece in a piecewise write. If
this is NULL, the standard polling method is used.
The callback function must return OCI_CONTINUE for the write to continue. If any other
error code is returned, the LOB write is terminated. The callback takes the following
parameters:
ctxp (IN)
The context for the callback function. Can be NULL.
bufp (IN/OUT)
A buffer pointer for the piece. This is the same as the bufp passed as an input to the
OCILobWrite() routine.
lenp (IN/OUT)
The length (in bytes) of the data in the buffer (IN), and the length (in bytes) of the
current piece in bufp (OUT).
piecep (OUT)
Which piece: OCI_NEXT_PIECE or OCI_LAST_PIECE.
changed_bufpp (OUT)
The callback function can put the address of a new buffer if it prefers to use a new
buffer for next piece to read. The default old buffer bufp is used if this parameter is set
to NULL.
changed_lenp (OUT)
Length of the new buffer, if provided.
csid (IN)
The character set ID of the data in the buffer. If this value is 0, then csid is set to the
client's NLS_LANG or NLS_CHAR value, depending on the value of csfrm.
csfrm (IN)
The character set form of the buffer data. The csfrm parameter must be consistent
with the type of the LOB.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT.
Comments
Writes a buffer into an internal LOB as specified. If LOB data exists, it is overwritten
with the data stored in the buffer. The buffer can be written to the LOB in a single

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piece with this call, or it can be provided piecewise using callbacks or a standard
polling method.

Note:
When you read or write LOBs, specify a character set form (csfrm) that
matches the form of the locator itself.

When you use the polling mode for OCILobWrite2(), the first call must specify values for
offset, byte_amtp, and char_amtp, but on subsequent polling calls to OCILobWrite2(),
you need not specify these values.
If the value of the piece parameter is OCI_FIRST_PIECE, data may need to be provided
through callbacks or polling.
If a callback function is defined in the cbfp parameter, then this callback function is
invoked to get the next piece after a piece is written to the pipe. Each piece is written
from bufp. If no callback function is defined, then OCILobWrite2() returns the
OCI_NEED_DATA error code. The application must call OCILobWrite2() again to write more
pieces of the LOB. In this mode, the buffer pointer and the length can be different in
each call if the pieces are of different sizes and from different locations.
A piece value of OCI_LAST_PIECE terminates the piecewise write, regardless of whether
the polling or callback method is used.
If the amount of data passed to the database (through either input mechanism) is less
than the amount specified by the byte_amtp or the char_amtp parameter, an ORA-22993
error is returned.
This function is valid for internal LOBs only. BFILEs are not allowed, because they are
read-only. If the LOB is a BLOB, the csid and csfrm parameters are ignored.
If both byte_amtp and char_amtp are set to point to zero amount, and OCI_FIRST_PIECE is
given as input, then polling mode is assumed and data is written until you specify
OCI_LAST_PIECE. For CLOBs and NCLOBs, byte_amtp and char_amtp return the data written
by each piece in terms of number of bytes and number of characters respectively. For
BLOBs, byte_amtp returns the number of bytes written by each piece, whereas char_amtp
is undefined on output.
To write data in UTF-16 format, set the csid parameter to OCI_UTF16ID. If the csid
parameter is set, it overrides the NLS_LANG environment variable.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.

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Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

PL/SQL REF CURSORs and Nested Tables in OCI for additional
information about Unicode format

•

The demonstration programs included with your Oracle Database
installation for a code sample showing the use of LOB reads and writes.

•

OCI Demonstration Programs

•

Runtime Data Allocation and Piecewise Operations in OCI for general
information about piecewise OCI operations

•

Polling Mode Operations in OCI

26.3.38 OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of size
greater than 4 GB.
Purpose
You can also use this function for LOBs smaller than 4 GB.
Syntax
sword OCILobWriteAppend2 ( OCISvcCtx
OCIError
OCILobLocator
oraub8
oraub8
void
oraub8
ub1
void
OCICallbackLobWrite2
(
void
void

*svchp,
*errhp,
*locp,
*byte_amtp,
*char_amtp,
*bufp,
buflen,
piece,
*ctxp,
(cbfp)
*ctxp,
*bufp,

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ub2
ub1

oraub8 *lenp,
ub1
*piecep
void
**changed_bufpp,
oraub8 *changed_lenp
)
csid,
csfrm);

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator that uniquely references a LOB.
byte_amtp (IN/OUT)
IN - The number of bytes to write to the database. Used for BLOB. For CLOB and NCLOB it
is used only when char_amtp is zero.
OUT - The number of bytes written to the database.
char_amtp (IN/OUT)
IN - The maximum number of characters to write to the database. Ignored for BLOB.
OUT - The number of characters written to the database. Undefined for BLOB.
bufp (IN)
The pointer to a buffer from which the piece is written. The length of the data in the
buffer is assumed to be the value passed in buflen. Even if the data is being written in
pieces, bufp must contain the first piece of the LOB when this call is invoked. If a
callback is provided, bufp must not be used to provide data or an error results.
buflen (IN)
The length, in bytes, of the data in the buffer. Note that this parameter assumes an 8bit byte. If your operating system uses a longer byte, the value of buflen must be
adjusted accordingly.
piece (IN)
Which piece of the buffer is being written. The default value for this parameter is
OCI_ONE_PIECE, indicating that the buffer is written in a single piece. The following other
values are also possible for piecewise or callback mode: OCI_FIRST_PIECE,
OCI_NEXT_PIECE, and OCI_LAST_PIECE.
ctxp (IN)
The context for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece in a piecewise write. If
this is NULL, the standard polling method is used. The callback function must return
OCI_CONTINUE for the write to continue. If any other error code is returned, the LOB
write is terminated. The callback takes the following parameters:

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ctxp (IN)
The context for the callback function. Can be NULL.
bufp (IN/OUT)
A buffer pointer for the piece.
lenp (IN/OUT)
The length (in bytes) of the data in the buffer (IN), and the length (in bytes) of the
current piece in bufp (OUT).
piecep (OUT)
Which piece: OCI_NEXT_PIECE or OCI_LAST_PIECE.
changed_bufpp (OUT)
The callback function can put the address of a new buffer if it prefers to use a new
buffer for next piece to be written. The default old buffer bufp is used if this parameter
is set to NULL.
changed_lenp (OUT)
Length of the new buffer, if provided.
csid (IN)
The character set ID of the buffer data.
csfrm (IN)
The character set form of the buffer data.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT.
Comments
The buffer can be written to the LOB in a single piece with this call, or it can be
provided piecewise using callbacks or a standard polling method. If the value of the
piece parameter is OCI_FIRST_PIECE, data must be provided through callbacks or
polling. If a callback function is defined in the cbfp parameter, then this callback
function is invoked to get the next piece after a piece is written to the pipe. Each piece
is written from bufp. If no callback function is defined, then OCILobWriteAppend2()
returns the OCI_NEED_DATA error code.
The application must call OCILobWriteAppend2() again to write more pieces of the LOB.
In this mode, the buffer pointer and the length can be different in each call if the pieces
are of different sizes and from different locations. A piece value of OCI_LAST_PIECE
terminates the piecewise write.
The OCILobWriteAppend2() function is not supported if LOB buffering is enabled.
If the LOB is a BLOB, the csid and csfrm parameters are ignored.
If both byte_amtp and char_amtp are set to point to zero amount and OCI_FIRST_PIECE is
given as input, then polling mode is assumed and data is written until you specify
OCI_LAST_PIECE. For CLOBs and NCLOBs, byte_amtp and char_amtp return the data written
by each piece in terms of number of bytes and number of characters respectively. For
BLOBs, byte_amtp returns the number of bytes written by each piece whereas char_amtp
is undefined on output.

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It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit your transaction. When an internal LOB is closed, it updates the functional and
domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobAppend()
Appends a LOB value at the end of another LOB as specified.

•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
About Improving LOB Read/Write Performance

26.4 Streams Advanced Queuing and Publish-Subscribe
Functions
Lists and describes the Streams Advanced Queuing and publish-subscribe functions.
Table 26-3 lists the Streams Advanced Queuing and publish-subscribe functions that
are described in this section. Use functions that end in "2" for all new applications.

See Also:
Table B-1 for Streams Advanced Queuing programs

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Table 26-3

Advanced Queuing and Publish-Subscribe Functions

Function

Purpose

OCIAQDeq()

Performs an Advanced Queuing
dequeue operation

OCIAQDeqArray()

Dequeue an array of messages

OCIAQEnq()

Performs an Advanced Queuing
enqueue operation

OCIAQEnqArray()

Enqueue an array of messages

OCIAQListen2()

Listen on one or more queues on behalf
of a list of agents. Supports buffered
messaging and persistent queues.

OCISubscriptionDisable()

Disable a subscription registration to
turn off notifications

OCISubscriptionEnable()

Enable notifications on a subscription

OCISubscriptionPost()

Post to a subscription to receive
notifications

OCISubscriptionRegister()

Register a subscription

OCISubscriptionUnRegister()

Unregister a subscription

26.4.1 OCIAQDeq()
Purpose
Performs a dequeue operation using Streams Advanced Queuing with OCI.
Syntax
sword OCIAQDeq ( OCISvcCtx
*svch,
OCIError
*errh,
OraText
*queue_name,
OCIAQDeqOptions
*dequeue_options,
OCIAQMsgProperties *message_properties,
OCIType
*payload_tdo,
void
**payload,
void
**payload_ind,
OCIRaw
**msgid,
ub4
flags );

Parameters
svch (IN)
OCI service context.
errh (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
queue_name (IN)
The target queue for the dequeue operation.

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dequeue_options (IN)
The options for the dequeue operation; stored in an OCIAQDeqOptions descriptor, with
OCI type constant OCI_DTYPE_AQDEQ_OPTIONS.
OCI_DTYPE_AQDEQ_OPTIONS has the additional attribute OCI_ATTR_MSG_DELIVERY_MODE
(introduced in Oracle Database 10g Release 2) with the following values:
•

OCI_MSG_PERSISTENT (default)

•

OCI_MSG_BUFFERED

•

OCI_MSG_PERSISTENT_OR_BUFFERED

message_properties (OUT)
The message properties for the message; the properties are stored in an
OCIAQMsgProperties descriptor, with OCI type constant OCI_DTYPE_AQMSG_PROPERTIES,
which can have the following values:
•

OCI_AQ_PERSISTENT (default)

•

OCI_AQ_BUFFERED

payload_tdo (IN)
The TDO (type descriptor object) of an object type. For a raw queue, this parameter
should point to the TDO of SYS.RAW.
payload (IN/OUT)
A pointer to a pointer to a program variable buffer that is an instance of an object type.
For a raw queue, this parameter should point to an instance of OCIRaw.
Memory for the payload is dynamically allocated in the object cache. The application
can optionally call OCIObjectFree() to deallocate the payload instance when it is no
longer needed. If the pointer to the program variable buffer (*payload) is passed as
NULL, the buffer is implicitly allocated in the cache.
The application may choose to pass NULL for payload the first time OCIAQDeq() is called,
and let the OCI allocate the memory for the payload. It can then use a pointer to that
previously allocated memory in subsequent calls to OCIAQDeq().
To obtain a TDO for the payload, use OCITypeByName(), or OCITypeByRef().
The OCI provides functions that allow the user to set attributes of the payload, such
as its text. For information about setting these attributes, see "Manipulating Object
Attributes".
payload_ind (IN/OUT)
A pointer to a pointer to the program variable buffer containing the parallel indicator
structure for the object type.
The memory allocation rules for payload_ind are the same as those for payload.
msgid (OUT)
The message ID.
flags (IN)
Not currently used; pass as OCI_DEFAULT.
Comments
Users must have the AQ_USER_ROLE or privileges to execute the DBMS_AQ package to use
this call. The OCI environment must be initialized in object mode (using
OCIEnvCreate(), OCIEnvNlsCreate()), or OCIInitialize() (deprecated) to use this call.

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Related Topics
•

OCIObjectFree()
Frees and unpins an object instance.

•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCIAQEnq()
Performs an enqueue operation using Streams Advanced Queuing.

•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

OCI and Streams Advanced Queuing

•

Oracle Database Advanced Queuing User's Guide

26.4.2 OCIAQDeqArray()
Dequeues an array of messages from a queue.
Purpose
All messages in the array are dequeued with the same option and have the same
queue table payload column TDO.
Syntax
sword OCIAQDeqArray ( OCISvcCtx
OCIError
OraText
OCIAQDeqOptions
ub4
OCIAQMsgProperties
OCIType
void
void
OCIRaw
void
OCICallbackAQDeq

*svchp,
*errhp,
*queue_name,
*deqopt,
*iters,
**msgprop,
*payload_tdo,
**payload,
**payload_ind,
**msgid,
*ctxp,
(cbfp)
(
void
*ctxp,
void
**payload,

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ub4

void
),
flags );

**payload_ind

Parameters
svchp (IN)
OCI service context (unchanged from OCIAQDeq()).
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error (unchanged from OCIAQDeq()).
queue_name (IN)
The name of the queue from which messages are dequeued (unchanged from
OCIAQDeq()

deqopt (IN)
A pointer to an OCIAQDeqOptions descriptor (unchanged from OCIAQDeq()).
OCI_DTYPE_AQDEQ_OPTIONS OCI type constant has the additional attribute
OCI_ATTR_MSG_DELIVERY_MODE (introduced in Oracle Database 10g Release 2) with the
following values:
•

OCI_MSG_PERSISTENT (default)

•

OCI_MSG_BUFFERED

•

OCI_MSG_PERSISTENT_OR_BUFFERED

iters (IN/OUT)
On input, the number of messages to dequeue. On output, the number of messages
successfully dequeued.
msgprop (OUT)
An array of pointers to OCIAQMsgProperties descriptors, of OCI type constant
OCI_DTYPE_AQMSG_PROPERTIES, which can have the following values:
•

OCI_AQ_PERSISTENT (default)

•

OCI_AQ_BUFFERED

payload_tdo (OUT)
A pointer to the TDO of the queue table's payload column.
payload (OUT)
An array of pointers to dequeued messages.
payload_ind (OUT)
An array of pointers to indicators.
msgid (OUT)
An array of pointers to the message ID of the dequeued messages.
ctxp (IN)
The context that is passed to the callback function.

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cbfp (IN)
The callback that can be registered to provide a buffer pointer into which the
dequeued message is placed. If NULL, then messages are dequeued into buffers
pointed to by payload.
flags (IN)
Not currently used; pass as OCI_DEFAULT.
Comments
Users must have the AQ_USER_ROLE or privileges to execute the DBMS_AQ package to use
this call. The OCI environment must be initialized in object mode (using
OCIEnvCreate(), OCIEnvNlsCreate()), or OCIInitialize() (deprecated) to use this call.
A nonzero wait time, as specified in the OCIAQDeqOptions, is recognized only when there
are no messages in the queue. If the queue contains messages that are eligible for
dequeuing, then the OCIAQDeqArray() function dequeues up to iters messages and
returns immediately.
This function is not supported in nonblocking mode.
Related Topics
•

OCIAQDeq()

•

OCIAQEnqArray()
Enqueues an array of messages to a queue.

•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
•

OCI and Streams Advanced Queuing

•

Oracle Database Advanced Queuing User's Guide

26.4.3 OCIAQEnq()
Performs an enqueue operation using Streams Advanced Queuing.
Purpose
Performs an enqueue operation using Streams Advanced Queuing.

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Syntax
sword OCIAQEnq ( OCISvcCtx
*svch,
OCIError
*errh,
OraText
*queue_name,
OCIAQEnqOptions
*enqueue_options,
OCIAQMsgProperties *message_properties,
OCIType
*payload_tdo,
void
**payload,
void
**payload_ind,
OCIRaw
**msgid,
ub4
flags );

Parameters
svch (IN)
OCI service context.
errh (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
queue_name (IN)
The target queue for the enqueue operation.
enqueue_options (IN)
The options for the enqueue operation; stored in an OCIAQEnqOptions descriptor.
message_properties (IN)
The message properties for the message. The properties are stored in an
OCIAQMsgProperties descriptor, of OCI type constant OCI_DTYPE_AQMSG_PROPERTIES,
introduced in Oracle Database 10g Release 2.
Descriptor OCI_DTYPE_AQMSG_PROPERTIES has the attribute OCI_ATTR_MSG_DELIVERY_MODE,
which has the following values:
•

OCI_MSG_PERSISTENT (default)

•

OCI_MSG_BUFFERED

payload_tdo (IN)
The TDO (type descriptor object) of an object type. For a raw queue, this parameter
should point to the TDO of SYS.RAW.
payload (IN)
A pointer to a pointer to an instance of an object type. For a raw queue, this
parameter should point to an instance of OCIRaw.
OCI provides functions that allow the user to set attributes of the payload, such as its
text.

See Also:
Manipulating Object Attributes for information about setting these attributes

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payload_ind (IN)
A pointer to a pointer to the program variable buffer containing the parallel indicator
structure for the object type.
msgid (OUT)
The message ID.
flags (IN)
Not currently used; pass as OCI_DEFAULT.
Comments
Users must have the AQ_USER_ROLE or privileges to execute the DBMS_AQ package to use
this call.
The OCI environment must be initialized in object mode (using OCIEnvCreate(),
OCIEnvNlsCreate()), or OCIInitialize() (deprecated) to use this call.

See Also:
•

OCI and Streams Advanced Queuing for more information about OCI
and Advanced Queuing

•

Oracle Database Advanced Queuing User's Guide

To obtain a TDO for the payload, use OCITypeByName(), or OCITypeByRef().
Related Topics
•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCIAQDeq()

•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.4.4 OCIAQEnqArray()
Enqueues an array of messages to a queue.
Purpose
The array of messages is enqueued with the same options and has the same payload
column TDO.

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Syntax
sword OCIAQEnqArray ( OCISvcCtx
OCIError
OraText
OCIAQEnqOptions
ub4
OCIAQMsgProperties
OCIType
void
void
OCIRaw
void
OCICallbackAQEnq

ub4

*svchp,
*errhp,
*queue_name,
*enqopt,
*iters,
**msgprop,
*payload_tdo,
**payload,
**payload_ind,
**msgid,
*ctxp,
(cbfp)
(
void
*ctxp,
void
**payload,
void
**payload_ind
),
flags );

Parameters
svchp (IN)
The service context (unchanged from OCIAQEnq()).
errhp (IN/OUT)
The error handle (unchanged from OCIAQEnq()).
queue_name (IN)
The name of the queue in which messages are enqueued (unchanged from
OCIAQEnq()).
enqopt (IN)
A pointer to an OCIAQEnqOptions descriptor (unchanged from OCIAQEnq()).
iters (IN/OUT)
On input, the number of messages to enqueue. On output, the number of messages
successfully enqueued.
msgprop (IN)
An array of pointers to OCIAQMsgProperties descriptors, of OCI type constant
OCI_DTYPE_AQMSG_PROPERTIES, introduced in Oracle Database 10g Release 2.
OCI_DTYPE_AQMSG_PROPERTIES has the attribute OCI_ATTR_MSG_DELIVERY_MODE, which has
the following values:
•

OCI_MSG_PERSISTENT (default)

•

OCI_MSG_BUFFERED

payload_tdo (IN)
A pointer to the TDO of the queue table's payload column.
payload (IN)
An array of pointers to messages to be enqueued.
payload_ind (IN)
An array of pointers to indicators, or a NULL pointer if indicator variables are not used.

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msgid (OUT)
An array of pointers to the message ID of the enqueued messages, or a NULL pointer if
no message IDs are returned.
ctxp (IN)
The context that is passed to the registered callback function.
cbfp (IN)
A callback that can be registered to provide messages dynamically. If NULL, then all
messages must be materialized before calling OCIAQEnqArray().
flags (IN)
Not currently used; pass as OCI_DEFAULT.
Comments
This function is not supported in nonblocking mode.
Related Topics
•

OCIAQEnq()
Performs an enqueue operation using Streams Advanced Queuing.

•

OCIAQDeqArray()
Dequeues an array of messages from a queue.

•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.4.5 OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.
Purpose
Supports buffered messaging and persistent queues. Introduced in Oracle Database
10g Release 2.
Syntax
sword OCIAQListen2 (OCISvcCtx
*svchp,
OCIError
*errhp,
OCIAQAgent
**agent_list,
ub4
num_agents,
OCIAQListenOpts
*lopts,
OCIAQAgent
**agent,
OCIAQLisMsgProps *lmops,
ub4
flags);

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Parameters
svchpp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
agent_list (IN)
List of agents for which to monitor messages.
num_agents (IN)
Number of agents in the agent list.
lopts (IN)
Type constant OCI_DTYPE_AQLIS_OPTIONS has the following attributes:
•

OCI_ATTR_WAIT - Maximum wait time, in seconds, for the listen call

•

OCI_ATTR_MSG_DELIVERY_MODE - Has one of these values:

–

OCI_MSG_PERSISTENT

–

OCI_MSG_BUFFERED

–

OCI_MSG_PERSISTENT_OR_BUFFERED

agent (OUT)
Agent for which there is a message. OCIAgent is an OCI descriptor.
lmops (OUT)
OCI_DTYPE_AQLIS_MSG_PROPERTIES (listen message properties) has one attribute,
OCI_ATTR_MSG_DELIVERY_MODE, which has the following values:

•

OCI_MSG_PERSISTENT

•

OCI_MSG_BUFFERED

flags (IN)
Not currently used; pass as OCI_DEFAULT.
Comments
This is a blocking call that returns when there is a message ready for consumption for
an agent in the list. If there are no messages found when the wait time expires, an
error is returned.
Related Topics
•

OCIAQEnq()
Performs an enqueue operation using Streams Advanced Queuing.

•

OCIAQDeq()

•

OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.

•

OCISubscriptionEnable()
Enables a subscription registration that has been disabled.

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•

OCISubscriptionPost()
Posts to a subscription that allows all clients who are registered for the
subscription to get notifications.

•

OCISubscriptionRegister()
Registers a callback for message notification.

•

OCISubscriptionUnRegister()
Unregisters a subscription that turns off notifications.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.4.6 OCISubscriptionDisable()
Disables a subscription registration that turns off all notifications.
Purpose
Disables a subscription registration that turns off all notifications.
Syntax
ub4 OCISubscriptionDisable ( OCISubscription
OCIError
ub4

*subscrhp,
*errhp
mode );

Parameters
subscrhp (IN)
A subscription handle with the OCI_ATTR_SUBSCR_NAME and OCI_ATTR_SUBSCR_NAMESPACE
attributes set.

See Also:
Subscription Handle Attributes
errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
Call-specific mode. The only valid value is OCI_DEFAULT. OCI_DEFAULT executes the
default call that discards all notifications on this subscription until the subscription is
enabled.
Comments
This call is used to temporarily turn off notifications. This is useful when the application
is running a critical section of the code and should not be interrupted.
The user need not be connected or authenticated to perform this operation. A
registration must have been performed to the subscription specified by the
subscription handle before this call is made.
All notifications after an OCISubscriptionDisable() are discarded by the system until an
OCISubscriptionEnable() is performed.

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Related Topics
•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCISubscriptionEnable()
Enables a subscription registration that has been disabled.

•

OCISubscriptionPost()
Posts to a subscription that allows all clients who are registered for the
subscription to get notifications.

•

OCISubscriptionRegister()
Registers a callback for message notification.

•

OCISubscriptionUnRegister()
Unregisters a subscription that turns off notifications.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.4.7 OCISubscriptionEnable()
Enables a subscription registration that has been disabled.
Purpose
This turns on all notifications.
Syntax
ub4 OCISubscriptionEnable ( OCISubscription
OCIError
ub4

*subscrhp,
*errhp
mode );

Parameters
subscrhp (IN)
A subscription handle with the OCI_ATTR_SUBSCR_NAME and OCI_ATTR_SUBSCR_NAMESPACE
attributes set.

See Also:
Subscription Handle Attributes
errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
Call-specific mode. The only valid value is OCI_DEFAULT. This value executes the
default call that buffers all notifications on this subscription until a subsequent enable
is performed.

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Comments
This call is used to turn on notifications after a subscription registration has been
disabled.
The user need not be connected or authenticated to perform this operation. A
registration must have been done for the specified subscription before this call is
made.
Related Topics
•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.

•

OCISubscriptionRegister()
Registers a callback for message notification.

•

OCISubscriptionUnRegister()
Unregisters a subscription that turns off notifications.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.4.8 OCISubscriptionPost()
Posts to a subscription that allows all clients who are registered for the subscription to
get notifications.
Purpose
Posts to a subscription that allows all clients who are registered for the subscription to
get notifications.
Syntax
ub4 OCISubscriptionPost ( OCISvcCtx
OCISubscription
ub2
OCIError
ub4

*svchp,
**subscrhpp,
count,
*errhp
mode );

Parameters
svchp (IN)
An OCI service context (after release 7). This service context should have a valid
authenticated user handle.
subscrhpp (IN)
An array of subscription handles. Each element of this array should be a subscription
handle with the OCI_ATTR_SUBSCR_NAME and OCI_ATTR_SUBSCR_NAMESPACE attributes set.

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See Also:
Subscription Handle Attributes
The OCI_ATTR_SUBSCR_PAYLOAD attribute must be set for each subscription handle before
this call. If it is not set, the payload is assumed to be NULL and no payload is delivered
when the notification is received by the clients that have registered interest. Note that
the caller must preserve the payload until the post is done, as the OCIAttrSet() call
keeps track of the reference to the payload but does not copy the contents.
count (IN)
The number of elements in the subscription handle array.
errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
Call-specific mode. The only valid value is OCI_DEFAULT. This value executes the
default call.
Comments
Posting to a subscription involves identifying the subscription name and the payload if
desired. If no payload is associated, the payload length can be set to 0.
This call provides a best-effort guarantee. A notification goes to registered clients at
most once.
This call is primarily used for nonpersistent notification and is useful for several system
events. If the application needs more rigid guarantees, it can use the Advanced
Queuing functionality by enqueuing to the queue.
Related Topics
•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.

•

OCISubscriptionEnable()
Enables a subscription registration that has been disabled.

•

OCISubscriptionRegister()
Registers a callback for message notification.

•

OCISubscriptionUnRegister()
Unregisters a subscription that turns off notifications.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.4.9 OCISubscriptionRegister()
Registers a callback for message notification.
Purpose
Registers a callback for message notification.
Syntax
ub4 OCISubscriptionRegister ( OCISvcCtx
OCISubscription
ub2
OCIError
ub4

*svchp,
**subscrhpp,
count,
*errhp
mode );

Parameters
svchp (IN)
An OCI service context (after release 7). This service context should have a valid
authenticated user handle.
subscrhpp (IN)
An array of subscription handles. Each element of this array should be a subscription
handle with all of the following attributes set:
•

OCI_ATTR_SUBSCR_NAME

•

OCI_ATTR_SUBSCR_NAMESPACE

•

OCI_ATTR_SUBSCR_RECPTPROTO

Otherwise, an error is returned.
One of the following attributes must also be set:
•

OCI_ATTR_SUBSCR_CALLBACK

•

OCI_ATTR_SUBSCR_CTX

•

OCI_ATTR_SUBSCR_RECPT

See Also:
Subscription Handle Attributes for information about the handle attributes

When a notification is received for the registration denoted by subscrhpp[i], either the
user-defined callback function (OCI_ATTR_SUBSCR_CALLBACK) set for subscrhpp[i] is
invoked with the context (OCI_ATTR_SUBSCR_CTX) set for subscrhpp[i], or an email is sent
to (OCI_ATTR_SUBSCR_RECPT) set for subscrhpp[i], or the PL/SQL procedure
(OCI_ATTR_SUBSCR_RECPT) set for subscrhpp[i] is invoked in the database, provided the
subscriber of subscrhpp[i] has the appropriate permissions on the procedure.
count (IN)
The number of elements in the subscription handle array.

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errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
Call-specific mode. Valid values are:
•

OCI_DEFAULT - Use when there is only one server DN in the server DN descriptor.

The registration request is sent to the database. If a database connection is not
available, the registration request is detoured to the LDAP server.
•

OCI_REG_LDAPONLY - The registration request is sent directly to the LDAP server. Use

this mode when there are multiple server DNs in the server DN descriptor, or you
are certain that a database connection is not available.
Whenever a new client process comes up, or an old one goes down and comes back
up, it must register for all subscriptions of interest. If the client stays up and the server
first goes down and then comes back up, the client continues to receive notifications
for registrations that are DISCONNECTED. However, the client does not receive
notifications for CONNECTED registrations, as they are lost after the server goes
down and comes back up.
Comments
This call is invoked for registration to a subscription that identifies the subscription
name of interest and the associated callback to be invoked. Interest in several
subscriptions can be registered simultaneously.
This interface is only valid for the asynchronous mode of message delivery. In this
mode, a subscriber issues a registration call that specifies a callback. When messages
are received that match the subscription criteria, the callback is invoked. The callback
may then issue an explicit message_receive (dequeue) to retrieve the message.
The user must specify a subscription handle at registration time with the namespace
attribute set to OCI_SUBSCR_NAMESPACE_AQ.
The subscription name is the string SCHEMA.QUEUE if the registration is for a single
consumer queue and SCHEMA.QUEUE:CONSUMER_NAME if the registration is for a
multiconsumer queue. The string should be in uppercase.
Each namespace has its own privilege model. If the user performing the registration is
not entitled to register in the namespace for the specified subscription, an error is
returned.
Related Topics
•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.

•

OCISubscriptionEnable()
Enables a subscription registration that has been disabled.

•

OCISubscriptionPost()
Posts to a subscription that allows all clients who are registered for the
subscription to get notifications.

•

OCISubscriptionUnRegister()
Unregisters a subscription that turns off notifications.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.4.10 OCISubscriptionUnRegister()
Unregisters a subscription that turns off notifications.
Purpose
Unregisters a subscription that turns off notifications.
Syntax
ub4 OCISubscriptionUnRegister ( OCISvcCtx
OCISubscription
OCIError
ub4

*svchp,
*subscrhp,
*errhp
mode );

Parameters
svchp (IN)
An OCI service context (after release 7). This service context should have a valid
authenticated user handle.
subscrhp (IN)
A subscription handle with the OCI_ATTR_SUBSCR_NAME and OCI_ATTR_SUBSCR_NAMESPACE
attributes set.

See Also:
Subscription Handle Attributes
errhp (OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
Call-specific mode. Valid values are:
•

OCI_DEFAULT - Use when there is only one server DN in the server DN descriptor.

The registration request is sent to the database. If a database connection is not
available, the registration request is detoured to the LDAP server.
•

OCI_REG_LDAPONLY - The registration request is sent directly to the LDAP server. Use

this mode when there are multiple server DNs in the server DN descriptor, or you
are certain that a database connection is not available.
Comments
Unregistering a subscription ensures that the user does not receive notifications
regarding the specified subscription in the future. If the user wants to resume
notification, then the only option is to reregister for the subscription.
All notifications that would otherwise have been delivered are not delivered after a
subsequent registration is performed because the user is no longer in the list of
interested clients.

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Related Topics
•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

•

OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.

•

OCISubscriptionEnable()
Enables a subscription registration that has been disabled.

•

OCISubscriptionPost()
Posts to a subscription that allows all clients who are registered for the
subscription to get notifications.

•

OCISubscriptionRegister()
Registers a callback for message notification.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5 Direct Path Loading Functions
Lists and describes the direct path loading functions.
Table 26-4 lists the direct path loading functions that are described in this section.
Table 26-4

Direct Path Loading Functions

Function

Purpose

OCIDirPathAbort()

Terminate a direct path operation

OCIDirPathColArrayEntryGet()

Get a specified entry in a column array

OCIDirPathColArrayEntrySet()

Set a specified entry in a column array
to a specific value

OCIDirPathColArrayReset()

Reset the row array state

OCIDirPathColArrayRowGet()

Get the base row pointers for a specified
row number

OCIDirPathColArrayToStream()

Convert from a column array to a direct
path stream format

OCIDirPathDataSave()

Do a data savepoint, or commit the
loaded data and finish the load
operation

OCIDirPathFinish()

Finish and commit the loaded data

OCIDirPathFlushRow()

Deprecated.

OCIDirPathLoadStream()

Load the data converted to direct path
stream format

OCIDirPathPrepare()

Prepare direct path interface to convert
or load rows

OCIDirPathStreamReset()

Reset the direct path stream state

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26.5.1 OCIDirPathAbort()
Terminates a direct path operation.
Purpose
Terminates a direct path operation.
Syntax
sword OCIDirPathAbort

( OCIDirPathCtx
OCIError

*dpctx,
*errhp );

Parameters
dpctx (IN)
Direct path context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
All state that was maintained by the server on behalf of the direct path operation is
destroyed by a termination. For a direct path load, the data loaded before the
terminate operation is not visible to any queries. However, the data may still consume
space in the segments that are being loaded. Any load completion operations, such as
index maintenance operations, are not performed.
Related Topics
•

OCIDirPathFinish()
Finishes the direct path load operation.

•

OCIDirPathPrepare()

•

OCIDirPathLoadStream()
Loads the data converted to direct path stream format.

•

OCIDirPathStreamReset()
Resets the direct path stream state.

•

OCIDirPathDataSave()
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.2 OCIDirPathColArrayEntryGet()
Purpose
Gets a specified entry in a column array.

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Syntax
sword OCIDirPathColArrayEntryGet ( OCIDirPathColArray *dpca,
OCIError
*errhp,
ub4
rownum,
ub2
colIdx,
ub1
**cvalpp,
ub4
*clenp,
ub1
*cflgp );

Parameters
dpca (IN/OUT)
Direct path column array handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
rownum (IN)
Zero-based row offset.
colIdx (IN)
The column's index used when building the column parameter list.
cvalpp (IN/OUT)
Pointer to pointer to column data.
clenp (IN/OUT)
Pointer to length of column data.
cflgp (IN/OUT)
Pointer to column flag.
One of these values is returned:
•

OCI_DIRPATH_COL_COMPLETE - All data for the column is present.

•

OCI_DIRPATH_COL_NULL - Column is NULL.

•

OCI_DIRPATH_COL_PARTIAL - Partial column data is being supplied.

Comments
If cflgp is set to OCI_DIRPATH_COL_NULL, the cvalpp and clenp parameters are not set by
this operation.
Related Topics
•

OCIDirPathColArrayEntrySet()
Sets a specified entry in a column array to the supplied values.

•

OCIDirPathColArrayRowGet()
Gets the column array row pointers for a given row number.

•

OCIDirPathColArrayReset()
Resets the column array state.

•

OCIDirPathColArrayToStream()
Converts from column array format to a direct path stream format.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.3 OCIDirPathColArrayEntrySet()
Sets a specified entry in a column array to the supplied values.
Purpose
Sets a specified entry in a column array to the supplied values.
Syntax
sword OCIDirPathColArrayEntrySet ( OCIDirPathColArray
OCIError
ub4
ub2
ub1
ub4
ub1

*dpca,
*errhp,
rownum,
colIdx,
*cvalp,
clen,
cflg );

Parameters
dpca (IN/OUT)
Direct path column array handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
rownum (IN)
Zero-based row offset.
colIdx (IN)
The column's index used when building the column parameter list.
cvalp (IN)
Pointer to column data.
clen (IN)
Length of column data.
cflg (IN)
Column flag. One of these values is returned:
•

OCI_DIRPATH_COL_COMPLETE - All data for the column is present.

•

OCI_DIRPATH_COL_NULL - Column is NULL.

•

OCI_DIRPATH_COL_PARTIAL - Partial column data is being supplied.

Comments
If cflg is set to OCI_DIRPATH_COL_NULL, the cvalp and clen parameters are not used.
Example
This example sets the source of data for the first row in a column array to addr, with a
length of len. In this example, the column is identified by colId.

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err = OCIDirPathColArrayEntrySet(dpca, errhp, (ub2)0, colId, addr, len,
OCI_DIRPATH_COL_COMPLETE);

Related Topics
•

OCIDirPathColArrayEntryGet()

•

OCIDirPathColArrayRowGet()
Gets the column array row pointers for a given row number.

•

OCIDirPathColArrayReset()
Resets the column array state.

•

OCIDirPathColArrayToStream()
Converts from column array format to a direct path stream format.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.4 OCIDirPathColArrayReset()
Resets the column array state.
Purpose
Resets the column array state.
Syntax
sword OCIDirPathColArrayReset ( OCIDirPathColArray
OCIError

*dpca,
*errhp );

Parameters
dpca (IN)
Direct path column array handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
Resetting the column array state is necessary when piecing in a large column and an
error occurs in the middle of loading the column. Do not reset the column array if the
last OCIDirPathColArrayReset() call returned OCI_NEED_DATA or OCI_CONTINUE. That is, you
are in the middle of a row conversion. Use OCI_DIRPATH_COL_ERROR to purge the
current row for OCI_NEED_DATA.
Related Topics
•

OCIDirPathColArrayEntryGet()

•

OCIDirPathColArrayEntrySet()
Sets a specified entry in a column array to the supplied values.

•

OCIDirPathColArrayRowGet()
Gets the column array row pointers for a given row number.

•

OCIDirPathColArrayToStream()
Converts from column array format to a direct path stream format.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.5 OCIDirPathColArrayRowGet()
Gets the column array row pointers for a given row number.
Purpose
Gets the column array row pointers for a given row number.
Syntax
sword OCIDirPathColArrayRowGet ( OCIDirPathColArray
OCIError
ub4
ub1
ub4
ub1

*dpca,
*errhp,
rownum,
***cvalppp,
**clenpp,
**cflgpp );

Parameters
dpca (IN/OUT)
Direct path column array handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
rownum (IN)
Zero-based row offset
cvalppp (IN/OUT)
Pointer to vector of pointers to column data
clenpp (IN/OUT)
Pointer to vector of column data lengths
cflgpp (IN/OUT)
Pointer to vector of column flags
Comments
Returns pointers to column array entries for the given row. This allows the application
to do simple pointer arithmetic to iterate across the columns of the specific row. You
can use this interface to efficiently get or set the column array entries of a row, as
opposed to calling OCIDirPathColArrayEntrySet() for every column. The application is
also responsible for not dereferencing memory beyond the column array boundaries.
The dimensions of the column array are available as attributes of the column array.
Related Topics
•

OCIDirPathColArrayEntryGet()

•

OCIDirPathColArrayEntrySet()
Sets a specified entry in a column array to the supplied values.

•

OCIDirPathColArrayReset()
Resets the column array state.

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•

OCIDirPathColArrayToStream()
Converts from column array format to a direct path stream format.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.6 OCIDirPathColArrayToStream()
Converts from column array format to a direct path stream format.
Purpose
Converts from column array format to a direct path stream format.
Syntax
sword OCIDirPathColArrayToStream ( OCIDirPathColArray
OCIDirPathCtx const
OCIDirPathStream
OCIError
ub4
ub4

*dpca,
*dpctx,
*dpstr,
*errhp,
rowcnt,
rowoff );

Parameters
dpca (IN)
Direct path column array handle.
dpctx (IN)
Direct path context handle for the object being loaded.
dpstr (IN/OUT)
Direct path stream handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
rowcnt (IN)
Number of rows in the column array.
rowoff (IN)
Starting index in the column array.
Comments
This interface is used to convert a column array representation of data in its external
format to a direct path stream format. The converted format is suitable for loading with
OCIDirPathLoadStream().
The column data in direct path stream format is converted to its Oracle Database
internal representation. All conversions are done on the client side of the two-task
interface; all conversion errors occur synchronously with the call to this interface.
Information concerning which row and column an error occurred on is available as an
attribute of the column array handle.

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Note that in a threaded environment, concurrent OCIDirPathColArrayToStream()
operations can be referencing the same direct path context handle. However, the
direct path context handle is not modified by this interface.
The return codes for this call are:
•

OCI_SUCCESS - All data in the column array was successfully converted to stream
format. The column array attribute OCI_ATTR_ROW_COUNT is the number of rows

processed.
•

OCI_ERROR - An error occurred during conversion; the error handle contains the
error information. The column array attribute OCI_ATTR_ROW_COUNT is the number of
rows successfully converted in the last call. The attribute OCI_ATTR_COL_COUNT

contains the column index into the column array for the column that caused the
error. A stream must always be loaded after column array to stream conversion
returns OCI_ERROR. It cannot be reset or converted to until it is loaded.
•

OCI_CONTINUE - Not all of the data in the column array could be converted to stream

format. The stream buffer is not large enough to contain all of the column array
data. The caller should either load the data, save the data to a file, or use another
stream and call OCIDirPathColArrayToStream() again to convert the remainder of
the column array data. The column array attribute OCI_ATTR_ROW_COUNT is the
number of rows successfully converted in the last call. The row offset must be
updated for the next conversion; internal state does keep track of the column to
continue conversion from. The OCI_ATTR_ROW_COUNT value must be added to the
previous row offset by the caller.
•

OCI_NEED_DATA - All of the data in the column array was successfully converted, but

a partial column was encountered. The caller should load the resulting stream, and
supply the remainder of the row, iteratively if necessary. The column array
attribute OCI_ATTR_ROW_COUNT is the number of rows successfully converted in the
last call. The attribute OCI_ATTR_COL_COUNT contains the column index into the
column array for the column that is marked partial.
Related Topics
•

OCIDirPathLoadStream()
Loads the data converted to direct path stream format.

•

OCIDirPathColArrayEntryGet()

•

OCIDirPathColArrayEntrySet()
Sets a specified entry in a column array to the supplied values.

•

OCIDirPathColArrayReset()
Resets the column array state.

•

OCIDirPathColArrayRowGet()
Gets the column array row pointers for a given row number.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.5.7 OCIDirPathDataSave()
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.
Purpose
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.
Syntax
sword OCIDirPathDataSave ( OCIDirPathCtx
OCIError
ub4

*dpctx,
*errhp,
action );

Parameters
dpctx (IN)
Direct path context handle for the object loaded.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
action (IN)
Values for action parameter to OCIDirPathDataSave() are as follows:
•

OCI_DIRPATH_DATASAVE_SAVEONLY - To execute a data savepoint only

•

OCI_DIRPATH_DATASAVE_FINISH - To commit the loaded data and call the direct

finishing function
Comments
A return value of OCI_SUCCESS indicates that the backend has properly executed a data
savepoint or executed the finishing logic.
Executing a data savepoint is not allowed for LOBs.
Executing the finishing logic is different from properly terminating the load, because
resources allocated are not freed.
Related Topics
•

OCIDirPathAbort()
Terminates a direct path operation.

•

OCIDirPathFinish()
Finishes the direct path load operation.

•

OCIDirPathPrepare()

•

OCIDirPathStreamReset()
Resets the direct path stream state.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.5.8 OCIDirPathFinish()
Finishes the direct path load operation.
Purpose
Finishes the direct path load operation.
Syntax
sword OCIDirPathFinish (

OCIDirPathCtx
OCIError

*dpctx,
*errhp );

Parameters
dpctx (IN)
Direct path context handle for the object loaded.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
After the load has completed, and the loaded data is to be committed, the direct path
finishing function is called. Finish is not allowed until all streams have been loaded,
and there is not a partially loaded row.
A return value of OCI_SUCCESS indicates that the backend has properly terminated the
load.
Related Topics
•

OCIDirPathAbort()
Terminates a direct path operation.

•

OCIDirPathDataSave()
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.

•

OCIDirPathPrepare()

•

OCIDirPathStreamReset()
Resets the direct path stream state.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.9 OCIDirPathFlushRow()
Flushes a partially loaded row from the server. This function is deprecated.
Purpose
Flushes a partially loaded row from the server. This function is deprecated.

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Syntax
sword OCIDirPathFlushRow (

OCIDirPathCtx
OCIError

*dpctx,
*errhp );

Parameters
dpctx (IN)
Direct path context handle for the object loaded.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
This function is necessary when part of a row is loaded, but a conversion error occurs
on the next piece being processed by the application. Only the row currently in partial
state is discarded. If the server is not currently processing a partial row for the object
associated with the direct path context, this function does nothing.
Related Topics
•

OCIDirPathAbort()
Terminates a direct path operation.

•

OCIDirPathFinish()
Finishes the direct path load operation.

•

OCIDirPathPrepare()

•

OCIDirPathLoadStream()
Loads the data converted to direct path stream format.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.10 OCIDirPathLoadStream()
Loads the data converted to direct path stream format.
Purpose
Loads the data converted to direct path stream format.
Syntax
sword OCIDirPathLoadStream (

OCIDirPathCtx
OCIDirPathStream
OCIError

*dpctx,
*dpstr,
*errhp );

Parameters
dpctx (IN)
Direct path context handle for the object loaded.
dpstr (IN)
Direct path stream handle for the stream to load.

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errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
When the interface returns an error, information concerning the row in the column
array that sourced the stream can be obtained as an attribute of the direct path
stream. Also, the offset into the stream where the error occurred can be obtained as
an attribute of the stream.
Return codes for this function are:
•

OCI_SUCCESS - All data in the stream was successfully loaded.

•

OCI_ERROR - An error occurred while loading the data. The problem could be a
partition mapping error, a NULL constraint violation, a function-based index

evaluation error, or an out of space condition, such as cannot allocate extent.
OCI_ATTR_ROW_COUNT is the number of rows successfully loaded in the last call.

•

OCI_NEED_DATA - Last row was not complete. The caller must supply another row

piece. If the stream was sourced from a column array, the attribute
OCI_ATTR_ROW_COUNT is the number of complete rows successfully loaded in the last
call.
•

OCI_NO_DATA - Attempt to load an empty stream or a stream that has been

completely processed.
A stream must be repeatedly loaded until OCI_SUCCESS, OCI_NEED_DATA, or OCI_NO_DATA is
returned. For example, a stream cannot be reset if OCI_ERROR is returned from
OCIDirPathLoadStream().
Related Topics
•

OCIDirPathAbort()
Terminates a direct path operation.

•

OCIDirPathDataSave()
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.

•

OCIDirPathFinish()
Finishes the direct path load operation.

•

OCIDirPathPrepare()

•

OCIDirPathStreamReset()
Resets the direct path stream state.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.5.11 OCIDirPathPrepare()
Purpose
Prepares the direct path load interface before any rows can be converted or loaded.

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Syntax
sword OCIDirPathPrepare (

OCIDirPathCtx
OCISvcCtx
OCIError

*dpctx,
*svchp,
*errhp );

Parameters
dpctx (IN)
Direct path context handle for the object loaded.
svchp (IN)
Service context.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
After the name of the object to be operated on is set, the external attributes of the
column data are set, and all load options are set, the direct path interface must be
prepared with OCIDirPathPrepare() before any rows can be converted or loaded.
A return value of OCI_SUCCESS indicates that the backend has been properly initialized
for a direct path load operation. A nonzero return indicates an error. Possible errors
are:
•

Invalid context

•

Not connected to a server

•

Object name not set

•

Already prepared (cannot prepare twice)

•

Object not suitable for a direct path operation

Related Topics
•

OCIDirPathAbort()
Terminates a direct path operation.

•

OCIDirPathDataSave()
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.

•

OCIDirPathFinish()
Finishes the direct path load operation.

•

OCIDirPathStreamReset()
Resets the direct path stream state.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.5.12 OCIDirPathStreamReset()
Resets the direct path stream state.
Purpose
Resets the direct path stream state.
Syntax
sword OCIDirPathStreamReset ( OCIDirPathStream
OCIError

*dpstr,
*errhp );

Parameters
dpstr (IN)
Direct path stream handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
A direct path stream maintains the state that indicates where the next
OCIDirPathColArrayToStream() call should start writing into the stream. Normally, data is

appended to the end of the stream. A stream cannot be reset until it is successfully
loaded (the loading returned OCI_SUCCESS, OCI_NEED_DATA, or OCI_NO_DATA).
Related Topics
•

OCIDirPathAbort()
Terminates a direct path operation.

•

OCIDirPathDataSave()
Depending on the action requested, does a data savepoint, or commits the loaded
data and finishes the direct path load operation.

•

OCIDirPathFinish()
Finishes the direct path load operation.

•

OCIDirPathPrepare()

•

OCIDirPathColArrayToStream()
Converts from column array format to a direct path stream format.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6 Thread Management Functions
Lists and describes the thread management functions.
Table 26-5 lists the thread management functions that are described in this section.

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Table 26-5

Thread Management Functions

Function

Purpose

OCIThreadClose()

Close a thread handle

OCIThreadCreate()

Create a new thread

OCIThreadHandleGet()

Retrieve the OCIThreadHandle of the
thread in which it is called

OCIThreadHndDestroy()

Destroy and deallocate the thread handle

OCIThreadHndInit()

Allocate and initialize the thread handle

OCIThreadIdDestroy()

Destroy and deallocate a thread ID

OCIThreadIdGet()

Retrieve the OCIThreadId of the thread in
which it is called

OCIThreadIdInit()

Allocate and initialize the thread ID

OCIThreadIdNull()

Determine whether a given OCIThreadId
is the NULL thread ID

OCIThreadIdSame()

Determine whether two OCIThreadIds
represent the same thread

OCIThreadIdSet()

Set one OCIThreadId to another

OCIThreadIdSetNull()

Set the NULL thread ID to a given
OCIThreadId

OCIThreadInit()

Initialize OCIThread context

OCIThreadIsMulti()

Tell the caller whether the application is
running in a multithreaded environment
or a single-threaded environment

OCIThreadJoin()

Allow the calling thread to join with
another thread

OCIThreadKeyDestroy()

Destroy and deallocate the key pointed to
by key

OCIThreadKeyGet()

Get the calling thread's current value for
a key

OCIThreadKeyInit()

Create a key

OCIThreadKeySet()

Set the calling thread's value for a key

OCIThreadMutexAcquire()

Acquire a mutex for the thread in which it
is called

OCIThreadMutexDestroy()

Destroy and deallocate a mutex

OCIThreadMutexInit()

Allocate and initialize a mutex

OCIThreadMutexRelease()

Release a mutex

OCIThreadProcessInit()

Perform OCIThread process initialization

OCIThreadTerm()

Release the OCIThread context

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26.6.1 OCIThreadClose()
Closes a thread handle.
Purpose
Closes a thread handle.
Syntax
sword OCIThreadClose ( void
*hndl,
OCIError
*err,
OCIThreadHandle *tHnd );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tHnd (IN/OUT)
The OCIThread thread handle to close.
Comments
The tHnd parameter should be initialized by OCIThreadHndInit(). Both the thread handle
and the thread ID that was returned by the same call to OCIThreadCreate() are invalid
after the call to OCIThreadClose().
Related Topics
•

OCIThreadCreate()
Creates a new thread.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.2 OCIThreadCreate()
Creates a new thread.
Purpose
Creates a new thread.
Syntax
sword OCIThreadCreate ( void
OCIError
void (*start)
void

*hndl,
*err,
(void *),
*arg,

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OCIThreadId
*tid,
OCIThreadHandle *tHnd );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
start (IN)
The function in which the new thread should begin execution.
arg (IN)
The argument to give the function pointed to by start.
tid (IN/OUT)
If not NULL, gets the ID for the new thread.
tHnd (IN/OUT)
If not NULL, gets the handle for the new thread.
Comments
The new thread starts by executing a call to the function pointed to by start with the
argument given by arg. When that function returns, the new thread terminates. The
function should not return a value and should accept one parameter, a void. The call to
OCIThreadCreate() must be matched by a call to OCIThreadClose() if and only if tHnd is
non-NULL.
If tHnd is NULL, a thread ID placed in *tid is not valid in the calling thread because the
timing of the spawned threads termination is unknown.
The tid parameter should be initialized by OCIThreadIdInit() and tHnd should be
initialized by OCIThreadHndInit().
Related Topics
•

OCIThreadClose()
Closes a thread handle.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.3 OCIThreadHandleGet()
Retrieves the OCIThreadHandle of the thread in which it is called.
Purpose
Retrieves the OCIThreadHandle of the thread in which it is called.

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Syntax
sword OCIThreadHandleGet ( void
*hndl,
OCIError
*err,
OCIThreadHandle *tHnd );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tHnd (IN/OUT)
If not NULL, the location to place the thread handle for the thread.
Comments
The tHnd parameter should be initialized by OCIThreadHndInit().
The thread handle tHnd retrieved by this function must be closed with OCIThreadClose()
and destroyed by OCIThreadHndDestroy() after it is used.
Related Topics
•

OCIThreadHndDestroy()
Destroys and deallocates the thread handle.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIThreadClose()
Closes a thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.4 OCIThreadHndDestroy()
Destroys and deallocates the thread handle.
Purpose
Destroys and deallocates the thread handle.
Syntax
sword OCIThreadHndDestroy ( void
*hndl,
OCIError
*err,
OCIThreadHandle **thnd );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
thnd (IN/OUT)
The address of pointer to the thread handle to destroy.
Comments
The thnd parameter should be initialized by OCIThreadHndInit().
Related Topics
•

OCIThreadHandleGet()
Retrieves the OCIThreadHandle of the thread in which it is called.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.5 OCIThreadHndInit()
Allocates and initializes the thread handle.
Purpose
Allocates and initializes the thread handle.
Syntax
sword OCIThreadHndInit ( void
OCIError
OCIThreadHandle

*hndl,
*err,
**thnd );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
thnd (OUT)
The address of the pointer to the thread handle to initialize.
Related Topics
•

OCIThreadHandleGet()
Retrieves the OCIThreadHandle of the thread in which it is called.

•

OCIThreadHndDestroy()
Destroys and deallocates the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.6 OCIThreadIdDestroy()
Destroys and deallocates a thread ID.
Purpose
Destroys and deallocates a thread ID.
Syntax
sword OCIThreadIdDestroy (void
*hndl,
OCIError
*err,
OCIThreadId **tid );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
tid (IN/OUT)
Pointer to the thread ID to destroy.
Comments
The tid parameter should be initialized by OCIThreadHndInit().
Related Topics
•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.7 OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.
Purpose
Retrieves the OCIThreadId of the thread in which it is called.
Syntax
sword OCIThreadIdGet ( void
*hndl,
OCIError
*err,
OCIThreadId *tid );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tid (OUT)
This should point to the location in which to place the ID of the calling thread.
Comments
The tid parameter should be initialized by OCIThreadHndInit(). When OCIThread is
used in a single-threaded environment, OCIThreadIdGet() always places the same
value in the location pointed to by tid. The exact value itself is not important. The
important thing is that it is different from the NULL thread ID and that it is always the
same value.
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.8 OCIThreadIdInit()
Allocate and initialize the thread ID tid.
Purpose
Allocate and initialize the thread ID tid.
Syntax
sword OCIThreadIdInit ( void
*hndl,
OCIError
*err,
OCIThreadId **tid );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
tid (OUT)
Pointer to the thread ID to initialize.
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

Related Topics
•

OCIThreadTerm()
Releases the OCIThread context.

•

OCIThreadProcessInit()
Performs OCIThread process initialization.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.9 OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.
Purpose
Determines whether a given OCIThreadId is the NULL thread ID.
Syntax
sword OCIThreadIdNull ( void
OCIError
OCIThreadId
boolean

*hndl,
*err,
*tid,
*result );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tid (IN)
Pointer to the OCIThreadId to check.
result (IN/OUT)
Pointer to the result.
Comments
If tid is the NULL thread ID, result is set to TRUE. Otherwise, result is set to FALSE. The
tid parameter should be initialized by OCIThreadIdInit().
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.10 OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.
Purpose
Determines whether two OCIThreadIds represent the same thread.
Syntax
sword OCIThreadIdSame ( void
OCIError
OCIThreadId
OCIThreadId
boolean

*hndl,
*err,
*tid1,
*tid2,
*result );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tid1 (IN)
Pointer to the first OCIThreadId.
tid2 (IN)
Pointer to the second OCIThreadId.
result (IN/OUT)
Pointer to the result.
Comments
If tid1 and tid2 represent the same thread, result is set to TRUE. Otherwise, result is
set to FALSE. The result parameter is set to TRUE if both tid1 and tid2 are the NULL
thread ID. The parameters tid1 and tid2 should be initialized by OCIThreadIdInit().
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.11 OCIThreadIdSet()
Sets one OCIThreadId to another.
Purpose
Sets one OCIThreadId to another.
Syntax
sword OCIThreadIdSet ( void
OCIError
OCIThreadId
OCIThreadId

*hndl,
*err,
*tidDest,
*tidSrc );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
tidDest (OUT)
This should point to the location of the OCIThreadId to set to.
tidSrc (IN)
This should point to the OCIThreadId to set from.
Comments
The tid parameter should be initialized by OCIThreadIdInit().
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.12 OCIThreadIdSetNull()
Sets the NULL thread ID to a given OCIThreadId.
Purpose
Sets the NULL thread ID to a given OCIThreadId.
Syntax
sword OCIThreadIdSetNull ( void
*hndl,
OCIError
*err,
OCIThreadId *tid );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tid (OUT)
This should point to the OCIThreadId in which to put the NULL thread ID.
Comments
The tid parameter should be initialized by OCIThreadIdInit().
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.13 OCIThreadInit()
Initializes the OCIThread context.
Purpose
Initializes the OCIThread context.
Syntax
sword OCIThreadInit ( void
*hndl,
OCIError *err );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
Comments
It is illegal for OCIThread clients to try to examine the memory pointed to by the
returned pointer. It is safe to make concurrent calls to OCIThreadInit(). Unlike
OCIThreadProcessInit(), there is no need to have a first call that occurs before all the
others.
The first time OCIThreadInit() is called, it initializes the OCIThread context. It also
saves a pointer to the context in some system-dependent manner. Subsequent calls to
OCIThreadInit() return the same context.
Each call to OCIThreadInit() must eventually be matched by a call to OCIThreadTerm().

26.6.14 OCIThreadIsMulti()
Tells the caller whether the application is running in a multithreaded environment or a
single-threaded environment.
Purpose
Tells the caller whether the application is running in a multithreaded environment or a
single-threaded environment.
Syntax
boolean OCIThreadIsMulti ( );

Returns
TRUE if the environment is multithreaded.
FALSE if the environment is single-threaded.

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Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

26.6.15 OCIThreadJoin()
Allows the calling thread to join with another thread.
Purpose
Allows the calling thread to join with another thread.
Syntax
sword OCIThreadJoin ( void
*hndl,
OCIError
*err,
OCIThreadHandle *tHnd );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tHnd (IN)
The OCIThreadHandle of the thread to join with.
Comments
This function blocks the caller until the specified thread terminates.
The tHnd parameter should be initialized by OCIThreadHndInit(). The result of multiple
threads all trying to join with the same thread is undefined.
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

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•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

•

OCIThreadHndInit()
Allocates and initializes the thread handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.16 OCIThreadKeyDestroy()
Destroys and deallocates the key pointed to by key.
Purpose
Destroys and deallocates the key pointed to by key.
Syntax
sword OCIThreadKeyDestroy ( void
*hndl,
OCIError
*err,
OCIThreadKey **key );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
key (IN/OUT)
The OCIThreadKey in which to destroy the key.
Comments
This is different from the destructor function callback passed to the key create routine.
The function OCIThreadKeyDestroy() is used to terminate any resources that the
OCIThread acquired when it created key. The OCIThreadKeyDestFunc callback of
OCIThreadKeyInit() is a key value destructor; it does not operate on the key itself.
This must be called after the user has finished using the key. Not calling the
OCIThreadKeyDestroy() function may result in memory leaks.
Related Topics
•

OCIThreadKeyGet()
Gets the calling thread's current value for a key.

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•

OCIThreadKeyInit()
Creates a key.

•

OCIThreadKeySet()
Sets the calling thread's value for a key.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.17 OCIThreadKeyGet()
Gets the calling thread's current value for a key.
Purpose
Gets the calling thread's current value for a key.
Syntax
sword OCIThreadKeyGet ( void
*hndl,
OCIError
*err,
OCIThreadKey *key,
void
**pValue );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
key (IN)
The key.
pValue (IN/OUT)
The location in which to place the thread-specific key value.
Comments
It is illegal to use this function on a key that has not been created using
OCIThreadKeyInit().
If the calling thread has not yet assigned a value to the key, NULL is placed in the
location pointed to by pValue.
Related Topics
•

OCIThreadKeyDestroy()
Destroys and deallocates the key pointed to by key.

•

OCIThreadKeyInit()
Creates a key.

•

OCIThreadKeySet()
Sets the calling thread's value for a key.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.18 OCIThreadKeyInit()
Creates a key.
Purpose
Creates a key.
Syntax
sword OCIThreadKeyInit (void
*hndl,
OCIError
*err,
OCIThreadKey
**key,
OCIThreadKeyDestFunc
destFn );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
key (OUT)
The OCIThreadKey in which to create the new key.
destFn (IN)
The destructor for the key. NULL is permitted.
Comments
Each call to this routine allocates and generates a new key that is distinct from all
other keys. After this function executes successfully, a pointer to an allocated and
initialized key is returned. That key can be used with OCIThreadKeyGet() and
OCIThreadKeySet(). The initial value of the key is NULL for all threads.
It is illegal for this function to be called more than once with the same value for the key
parameter.
If the destFn parameter is not NULL, the routine pointed to by destFn is called whenever
a thread that has a non-NULL value for the key terminates. The routine is called with
one parameter. The parameter is the key's value for the thread at the time at which the
thread terminated. If the key does not need a destructor function, pass NULL for destFn.
Related Topics
•

OCIThreadKeyDestroy()
Destroys and deallocates the key pointed to by key.

•

OCIThreadKeyGet()
Gets the calling thread's current value for a key.

•

OCIThreadKeySet()
Sets the calling thread's value for a key.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.6.19 OCIThreadKeySet()
Sets the calling thread's value for a key.
Purpose
Sets the calling thread's value for a key.
Syntax
sword OCIThreadKeySet ( void
OCIError
OCIThreadKey
void

*hndl,
*err,
*key,
*value );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
key (IN/OUT)
The key.
value (IN)
The thread-specific value to set in the key.
Comments
It is illegal to use this function on a key that has not been created using
OCIThreadKeyInit().
Related Topics
•

OCIThreadKeyDestroy()
Destroys and deallocates the key pointed to by key.

•

OCIThreadKeyGet()
Gets the calling thread's current value for a key.

•

OCIThreadKeyInit()
Creates a key.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.20 OCIThreadMutexAcquire()
Acquires a mutex for the thread in which it is called.
Purpose
Acquires a mutex for the thread in which it is called.

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Syntax
sword OCIThreadMutexAcquire ( void
*hndl,
OCIError
*err,
OCIThreadMutex *mutex );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
mutex (IN/OUT)
The mutex to acquire.
Comments
If the mutex is held by another thread, the calling thread is blocked until it can acquire
the mutex.
It is illegal to attempt to acquire an uninitialized mutex.
This function's behavior is undefined if it is used by a thread to acquire a mutex that is
already held by that thread.
Related Topics
•

OCIThreadMutexDestroy()
Destroys and deallocates a mutex.

•

OCIThreadMutexInit()
Allocates and initializes a mutex.

•

OCIThreadMutexRelease()
Releases a mutex.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.21 OCIThreadMutexDestroy()
Destroys and deallocates a mutex.
Purpose
Destroys and deallocates a mutex.
Syntax
sword OCIThreadMutexDestroy ( void
*hndl,
OCIError
*err,
OCIThreadMutex **mutex );

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Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
mutex (IN/OUT)
The mutex to destroy.
Comments
Each mutex must be destroyed after it is no longer needed.
It is not legal to destroy a mutex that is uninitialized or is currently held by a thread.
The destruction of a mutex must not occur concurrently with any other operations on
the mutex. A mutex must not be used after it has been destroyed.
Related Topics
•

OCIThreadMutexAcquire()
Acquires a mutex for the thread in which it is called.

•

OCIThreadMutexInit()
Allocates and initializes a mutex.

•

OCIThreadMutexRelease()
Releases a mutex.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.22 OCIThreadMutexInit()
Allocates and initializes a mutex.
Purpose
Allocates and initializes a mutex.
Syntax
sword OCIThreadMutexInit ( void
*hndl,
OCIError
*err,
OCIThreadMutex **mutex );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().

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mutex (OUT)
The mutex to initialize.
Comments
All mutexes must be initialized before use.
Multiple threads must not initialize the same mutex simultaneously. Also, a mutex must
not be reinitialized until it has been destroyed (see OCIThreadMutexDestroy()).
Related Topics
•

OCIThreadMutexDestroy()
Destroys and deallocates a mutex.

•

OCIThreadMutexAcquire()
Acquires a mutex for the thread in which it is called.

•

OCIThreadMutexRelease()
Releases a mutex.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.23 OCIThreadMutexRelease()
Releases a mutex.
Purpose
Releases a mutex.
Syntax
sword OCIThreadMutexRelease ( void
*hndl,
OCIError
*err,
OCIThreadMutex *mutex );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
mutex (IN/OUT)
The mutex to release.
Comments
If there are any threads blocked on the mutex, one of them acquires it and becomes
unblocked.
It is illegal to attempt to release an uninitialized mutex. It is also illegal for a thread to
release a mutex that it does not hold.

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Related Topics
•

OCIThreadMutexDestroy()
Destroys and deallocates a mutex.

•

OCIThreadMutexInit()
Allocates and initializes a mutex.

•

OCIThreadMutexAcquire()
Acquires a mutex for the thread in which it is called.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.6.24 OCIThreadProcessInit()
Performs OCIThread process initialization.
Purpose
Performs OCIThread process initialization.
Syntax
void OCIThreadProcessInit ( );

Comments
Whether this function must be called depends on how OCIThread is going to be used.
In a single-threaded application, calling this function is optional. If it is called at all, the
first call to it must occur before calls to any other OCIThread functions. Subsequent
calls can be made without restriction; they do not have any effect.
In a multithreaded application, this function must be called. The first call to it must
occur strictly before any other OCIThread calls; that is, no other calls to OCIThread
functions (including other calls to this one) can be concurrent with the first call.
Subsequent calls to this function can be made without restriction; they do not have any
effect.
Related Topics
•

OCIThreadIdDestroy()
Destroys and deallocates a thread ID.

•

OCIThreadIdGet()
Retrieves the OCIThreadId of the thread in which it is called.

•

OCIThreadIdInit()
Allocate and initialize the thread ID tid.

•

OCIThreadIdNull()
Determines whether a given OCIThreadId is the NULL thread ID.

•

OCIThreadIdSame()
Determines whether two OCIThreadIds represent the same thread.

•

OCIThreadIdSet()
Sets one OCIThreadId to another.

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26.6.25 OCIThreadTerm()
Releases the OCIThread context.
Purpose
Releases the OCIThread context.
Syntax
sword OCIThreadTerm ( void
*hndl,
OCIError *err );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error and OCI_ERROR is returned, the error is
recorded in err and diagnostic information can be obtained by calling OCIErrorGet().
Comments
This function should be called exactly once for each call made to OCIThreadInit().
It is safe to make concurrent calls to OCIThreadTerm(). OCIThreadTerm() does not do
anything until it has been called as many times as OCIThreadInit() has been called.
When that happens, OCIThreadTerm() terminates the OCIThread layer and frees the
memory allocated for the context. Once this happens, the context should not be
reused. It is necessary to obtain a new one by calling OCIThreadInit().
Related Topics
•

OCIThreadInit()
Initializes the OCIThread context.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.7 Transaction Functions
Lists and describes the transaction functions.
Table 26-6 lists the transaction functions that are described in this section.
Table 26-6

Transaction Functions

Function

Purpose

OCITransCommit()

Commit a transaction on a service context

OCITransDetach()

Detach a transaction from a service context

OCITransForget()

Forget a prepared global transaction

OCITransMultiPrepare()

Prepare a transaction with multiple
branches in a single cell

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Table 26-6

(Cont.) Transaction Functions

Function

Purpose

OCITransPrepare()

Prepare a global transaction for commit

OCITransRollback()

Roll back a transaction

OCITransStart()

Start a transaction on a service context

26.7.1 OCITransCommit()
Commits the transaction associated with a specified service context.
Purpose
Commits the transaction associated with a specified service context.
Syntax
sword OCITransCommit ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
flags );

Parameters
svchp (IN)
The service context handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
flags (IN)
A flag used for one-phase commit optimization in global transactions.
OCI_DEFAULT - If the transaction is nondistributed, the flags parameter is ignored, and
OCI_DEFAULT can be passed as its value.
OCI_TRANS_TWOPHASE - OCI applications managing global transactions should pass this
value to the flags parameter for a two-phase commit. The default is one-phase
commit.
OCI_TRANS_WRITEIMMED - I/O is initiated by LGWR (Log Writer Process in the
background) to write the (in-memory) redo buffers to the online redo logs. IMMEDIATE
means that the redo buffers of the transaction are written out immediately by sending
a message to LGWR, which processes the message immediately.
OCI_TRANS_WRITEBATCH - No I/O is issued by LGWR to write the in-memory redo buffers
of the transaction to the online redo logs. BATCH means that the LGWR batches the
redo buffers before initiating I/O for the entire batch. An error occurs when you specify
both BATCH and IMMEDIATE. IMMEDIATE is the default.
OCI_TRANS_WRITEWAIT - LGWR is requested to write the redo for the commit to the
online redo logs, and the commit waits for the redo buffers to be written to the online
redo logs. WAIT means that the commit does not return until the in-memory redo
buffers corresponding to the transaction are written in the (persistent) online redo
logs.
OCI_TRANS_WRITENOWAIT - LGWR is requested to write the redo for the commit to the
online redo logs, but the commit returns without waiting for the buffers to be written to

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the online redo logs. NOWAIT means that the commit returns to the user before the inmemory redo buffers are flushed to the online redo logs. An error occurs when you
specify both WAIT and NOWAIT. WAIT is the default.

Note:
There is a potential for silent transaction loss when you use
OCI_TRANS_WRITENOWAIT. Transaction loss occurs silently with shutdown abort,
startup force, and any instance or node failure. On an Oracle RAC system,
asynchronously committed changes may not be immediately available to
read on other instances.
These last four options only affect the commit of top-level nondistributed transactions
and are ignored for externally coordinated distributed transactions. They can be
combined using the OR operator, subject to the stated restrictions.
Comments
The transaction currently associated with the service context is committed. If it is a
global transaction that the server cannot commit, this call additionally retrieves the
state of the transaction from the database to be returned to the user in the error
handle.
If the application has defined multiple transactions, this function operates on the
transaction currently associated with the service context. If the application is working
with only the implicit local transaction created when database changes are made, that
implicit transaction is committed.
If the application is running in the object mode, then the modified or updated objects in
the object cache for this transaction are also flushed and committed.
Under normal circumstances, OCITransCommit() returns with a status indicating that the
transaction has either been committed or rolled back. With global transactions, it is
possible that the transaction is now in doubt, meaning that it is neither committed nor
terminated. In this case, OCITransCommit() attempts to retrieve the status of the
transaction from the server. The status is returned.
Example
The following code example demonstrates the use of a simple local transaction, as
described in "Simple Local Transactions".
Using OCITransCommit() in a Simple Local Transaction
int main()
{
OCIEnv *envhp;
OCIServer *srvhp;
OCIError *errhp;
OCISvcCtx *svchp;
OCIStmt *stmthp;
void
*tmp;
text sqlstmt[128];
OCIEnvCreate(&envhp, OCI_DEFAULT, (void *)0, 0, 0, 0,
(size_t)0, (void *)0);

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OCIHandleAlloc( (void *) envhp, (void **) &errhp, (ub4) OCI_HTYPE_ERROR,
(size_t)0, (void **) 0);
OCIHandleAlloc( (void *) envhp, (void **) &srvhp, (ub4) OCI_HTYPE_SERVER,
(size_t)0, (void **) 0);
OCIServerAttach( srvhp, errhp, (text *) 0, (sb4) 0, (ub4) OCI_DEFAULT);
OCIHandleAlloc( (void *) envhp, (void **) &svchp, (ub4) OCI_HTYPE_SVCCTX,
(size_t)0, (void **) 0);
OCIHandleAlloc((void *)envhp, (void **)&stmthp, OCI_HTYPE_STMT, 0, 0);
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)srvhp, 0,
OCI_ATTR_SERVER, errhp);
OCILogon(envhp, errhp, &svchp, (text *)"HR", strlen("HR"),
(text *)"HR", strlen("HR"), 0, 0);
/* update hr.employees employee_id=7902, increment salary */
sprintf((char *)sqlstmt, "UPDATE EMPLOYEES SET SALARY = SALARY + 1 \
WHERE EMPLOYEE_ID = 7902");
OCIStmtPrepare(stmthp, errhp, sqlstmt, strlen((char *)sqlstmt),
OCI_NTV_SYNTAX, 0);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, 0, 0, 0);
OCITransCommit(svchp, errhp, (ub4) 0);
/* update hr.employees employee_id=7902, increment salary again, but rollback */
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, 0, 0, 0);
OCITransRollback(svchp, errhp, (ub4) 0);
}

Related Topics
•

OCITransRollback()
Rolls back the current transaction.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.7.2 OCITransDetach()
Detaches a global transaction.
Purpose
Detaches a global transaction.
Syntax
sword OCITransDetach ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
flags );

Parameters
svchp (IN)
The service context handle.

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errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
flags (IN)
You must pass a value of OCI_DEFAULT for this parameter.
Comments
Detaches a global transaction from the service context handle. The transaction
currently attached to the service context handle becomes inactive at the end of this
call. The transaction may be resumed later by calling OCITransStart(), specifying a
flags value of OCI_TRANS_RESUME.
When a transaction is detached, the value that was specified in the timeout parameter
of OCITransStart() when the transaction was started is used to determine the amount
of time the branch can remain inactive before being deleted by the server's PMON
process.

Note:
The transaction can be resumed by a different process than the one that
detached it, if the transaction has the same authorization. If this function is
called before a transaction is actually started, this function has no effect.

For example code demonstrating the use of OCITransDetach(), see the Examples
section of OCITransStart().
Related Topics
•

OCITransStart()
Sets the beginning of a transaction.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.7.3 OCITransForget()
Causes the server to forget a heuristically completed global transaction.
Purpose
Causes the server to forget a heuristically completed global transaction.
Syntax
sword OCITransForget ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
flags );

Parameters
svchp (IN)
The service context handle in which the transaction resides.

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errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
flags (IN)
You must pass OCI_DEFAULT for this parameter.
Comments
Forgets a heuristically completed global transaction. The server deletes the status of
the transaction from the system's pending transaction table.
You set the XID of the transaction to be forgotten as an attribute of the transaction
handle (OCI_ATTR_XID).
Related Topics
•

OCITransCommit()
Commits the transaction associated with a specified service context.

•

OCITransRollback()
Rolls back the current transaction.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.7.4 OCITransMultiPrepare()
Prepares a transaction with multiple branches in a single call.
Purpose
Prepares a transaction with multiple branches in a single call.
Syntax
sword OCITransMultiPrepare ( OCISvcCtx
ub4
OCITrans
OCIError

*svchp,
numBranches,
**txns,
**errhp);

Parameters
srvchp (IN)
The service context handle.
numBranches (IN)
The number of branches expected. It is also the array size for the next two
parameters.
txns (IN)
The array of transaction handles for the branches to prepare. They should all have the
OCI_ATTR_XID set. The global transaction ID should be the same.
errhp (IN)
The array of error handles. If OCI_SUCCESS is not returned, then these indicate which
branches received which errors.

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Comments
Prepares the specified global transaction for commit. This call is valid only for
distributed transactions. This call is an advanced performance feature intended for use
only in situations where the caller is responsible for preparing all the branches in a
transaction.
Related Topics
•

OCITransPrepare()
Prepares a global transaction for commit.

26.7.5 OCITransPrepare()
Prepares a global transaction for commit.
Purpose
Prepares a global transaction for commit.
Syntax
sword OCITransPrepare ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
flags );

Parameters
svchp (IN)
The service context handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
flags (IN)
You must pass OCI_DEFAULT for this parameter.
Comments
Prepares the specified global transaction for commit.
This call is valid only for global transactions.
The call returns OCI_SUCCESS_WITH_INFO if the transaction has not made any changes.
The error handle indicates that the transaction is read-only. The flags parameter is not
currently used.
Related Topics
•

OCITransCommit()
Commits the transaction associated with a specified service context.

•

OCITransForget()
Causes the server to forget a heuristically completed global transaction.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.7.6 OCITransRollback()
Rolls back the current transaction.
Purpose
Rolls back the current transaction.
Syntax
sword OCITransRollback ( void
OCIError
ub4

*svchp,
*errhp,
flags );

Parameters
svchp (IN)
A service context handle. The transaction currently set in the service context handle is
rolled back.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
flags (IN)
You must pass a value of OCI_DEFAULT for this parameter.
Comments
The current transaction— defined as the set of statements executed since the last
OCITransCommit() or since OCISessionBegin() —is rolled back.
If the application is running under object mode, then the modified or updated objects in
the object cache for this transaction are also rolled back.
Attempting to roll back a global transaction that is not currently active causes an error.
Examples
For example code demonstrating the use of OCITransRollback() see the Examples
section of OCITransCommit().
Related Topics
•

OCITransCommit()
Commits the transaction associated with a specified service context.

•

OCISessionBegin()
Creates a user session and begins a user session for a given server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.7.7 OCITransStart()
Sets the beginning of a transaction.
Purpose
Sets the beginning of a transaction.
Syntax
sword OCITransStart ( OCISvcCtx
OCIError
uword
ub4

*svchp,
*errhp,
timeout,
flags );

Parameters
svchp (IN/OUT)
The service context handle. The transaction context in the service context handle is
initialized at the end of the call if the flag specified a new transaction to be started.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
timeout (IN)
The time, in seconds, to wait for a transaction to become available for resumption
when OCI_TRANS_RESUME is specified. When OCI_TRANS_NEW is specified, the timeout
parameter indicates the number of seconds the transaction can be inactive before it is
automatically terminated by the system. A transaction is inactive between the time it is
detached (with OCITransDetach()) and the time it is resumed with OCITransStart().
flags (IN)
Specifies whether a new transaction is being started or an existing transaction is
being resumed. Also specifies serializability or read-only status. More than a single
value can be specified. By default, a read/write transaction is started. The flag values
are:
•

OCI_TRANS_NEW - Starts a new transaction branch. By default starts a tightly coupled

and migratable branch.
•

OCI_TRANS_TIGHT - Explicitly specifies a tightly coupled branch.

•

OCI_TRANS_LOOSE - Specifies a loosely coupled branch.

•

OCI_TRANS_RESUME - Resumes an existing transaction branch.

•

OCI_TRANS_READONLY - Starts a read-only transaction.

•

OCI_TRANS_SERIALIZABLE - Starts a serializable transaction.

•

OCI_TRANS_SEPARABLE - Separates the transaction after each call.

This flag results in a warning that the transaction was started using regular
transactions. Separated transactions are not supported through release 9.0.1 of
the server.

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An error message results if there is an error in your code or the transaction service.
The error indicates that you attempted an action on a transaction that has already
been prepared.
Comments
This function sets the beginning of a global or serializable transaction. The transaction
context currently associated with the service context handle is initialized at the end of
the call if the flags parameter specifies that a new transaction should be started.
The XID of the transaction is set as an attribute of the transaction handle
(OCI_ATTR_XID)
Examples
The following code example and the one following that one demonstrate the use of
OCI transactional calls for manipulating global transactions. The concept for a single
session operating on different branches, as shown in the following code example, is
illustrated by Figure 10-2.
Using OCITransStart() in a Single Session Operating on Different Branches
int main()
{
OCIEnv *envhp;
OCIServer *srvhp;
OCIError *errhp;
OCISvcCtx *svchp;
OCISession *usrhp;
OCIStmt *stmthp1, *stmthp2;
OCITrans *txnhp1, *txnhp2;
void
*tmp;
XID gxid;
text sqlstmt[128];
OCIEnvCreate(&envhp, OCI_DEFAULT, (void *)0, 0, 0, 0,
(size_t)0, (void *)0);
OCIHandleAlloc( (void *) envhp, (void **) &errhp, (ub4)
OCI_HTYPE_ERROR, 52, (void **) &tmp);
OCIHandleAlloc( (void *) envhp, (void **) &srvhp, (ub4)
OCI_HTYPE_SERVER, 52, (void **) &tmp);
OCIServerAttach( srvhp, errhp, (text *) 0, (sb4) 0, (ub4) OCI_DEFAULT);
OCIHandleAlloc( (void *) envhp, (void **) &svchp, (ub4) OCI_HTYPE_SVCCTX,
52, (void **) &tmp);
OCIHandleAlloc((void *)envhp, (void **)&stmthp1, OCI_HTYPE_STMT, 0, 0);
OCIHandleAlloc((void *)envhp, (void **)&stmthp2, OCI_HTYPE_STMT, 0, 0);
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)srvhp, 0,
OCI_ATTR_SERVER, errhp);
/* set the external name and internal name in server handle */
OCIAttrSet((void *)srvhp, OCI_HTYPE_SERVER, (void *) "demo", 0,
OCI_ATTR_EXTERNAL_NAME, errhp);
OCIAttrSet((void *)srvhp, OCI_HTYPE_SERVER, (void *) "txn demo", 0,
OCI_ATTR_INTERNAL_NAME, errhp);

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/* allocate a user context handle */
OCIHandleAlloc((void *)envhp, (void **)&usrhp, (ub4) OCI_HTYPE_SESSION,
(size_t) 0, (void **) 0);
OCIAttrSet((void *)usrhp, (ub4)OCI_HTYPE_SESSION, (void *)"HR",
(ub4)strlen("HR"), OCI_ATTR_USERNAME, errhp);
OCIAttrSet((void *)usrhp, (ub4)OCI_HTYPE_SESSION, (void *)"HR",
(ub4)strlen("HR"),OCI_ATTR_PASSWORD, errhp);
OCISessionBegin (svchp, errhp, usrhp, OCI_CRED_RDBMS, 0);
OCIAttrSet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX,
(void *)usrhp, (ub4)0, OCI_ATTR_SESSION, errhp);
/* allocate transaction handle 1 and set it in the service handle */
OCIHandleAlloc((void *)envhp, (void **)&txnhp1, OCI_HTYPE_TRANS, 0, 0);
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp1, 0,
OCI_ATTR_TRANS, errhp);
/* start a transaction with global transaction id = [1000, 123, 1] */
gxid.formatID = 1000; /* format id = 1000 */
gxid.gtrid_length = 3; /* gtrid = 123 */
gxid.data[0] = 1; gxid.data[1] = 2; gxid.data[2] = 3;
gxid.bqual_length = 1; /* bqual = 1 */
gxid.data[3] = 1;
OCIAttrSet((void *)txnhp1, OCI_HTYPE_TRANS, (void *)&gxid, sizeof(XID),
OCI_ATTR_XID, errhp);
/* start global transaction 1 with 60-second time to live when detached */
OCITransStart(svchp, errhp, 60, OCI_TRANS_NEW);
/* update hr.employees employee_id=7902, increment salary */
sprintf((char *)sqlstmt, "UPDATE EMPLOYEES SET SALARY = SALARY + 1 \
WHERE EMPLOYEE_ID = 7902");
OCIStmtPrepare(stmthp1, errhp, sqlstmt, strlen((char *)sqlstmt),
OCI_NTV_SYNTAX, 0);
OCIStmtExecute(svchp, stmthp1, errhp, 1, 0, 0, 0, 0);
/* detach the transaction */
OCITransDetach(svchp, errhp, 0);
/* allocate transaction handle 2 and set it in the service handle */
OCIHandleAlloc((void *)envhp, (void **)&txnhp2, OCI_HTYPE_TRANS, 0, 0);
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp2, 0,
OCI_ATTR_TRANS, errhp);
/* start a transaction with global transaction id = [1000, 124, 1] */
gxid.formatID = 1000; /* format id = 1000 */
gxid.gtrid_length = 3; /* gtrid = 124 */
gxid.data[0] = 1; gxid.data[1] = 2; gxid.data[2] = 4;
gxid.bqual_length = 1; /* bqual = 1 */
gxid.data[3] = 1;
OCIAttrSet((void *)txnhp2, OCI_HTYPE_TRANS, (void *)&gxid, sizeof(XID),
OCI_ATTR_XID, errhp);
/* start global transaction 2 with 90 second time to live when detached */
OCITransStart(svchp, errhp, 90, OCI_TRANS_NEW);

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/* update hr.employees employee_id=7934, increment salary */
sprintf((char *)sqlstmt, "UPDATE EMPLOYEES SET SALARY = SALARY + 1 \
WHERE EMPLOYEE_ID = 7934");
OCIStmtPrepare(stmthp2, errhp, sqlstmt, strlen((char *)sqlstmt),
OCI_NTV_SYNTAX, 0);
OCIStmtExecute(svchp, stmthp2, errhp, 1, 0, 0, 0, 0);
/* detach the transaction */
OCITransDetach(svchp, errhp, 0);
/* Resume transaction 1, increment salary and commit it */
/* Set transaction handle 1 into the service handle */
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp1, 0,
OCI_ATTR_TRANS, errhp);
/* attach to transaction 1, wait for 10 seconds if the transaction is busy */
/* The wait is clearly not required in this example because no other */
/* process/thread is using the transaction. It is only for illustration */
OCITransStart(svchp, errhp, 10, OCI_TRANS_RESUME);
OCIStmtExecute(svchp, stmthp1, errhp, 1, 0, 0, 0, 0);
OCITransCommit(svchp, errhp, (ub4) 0);
/* attach to transaction 2 and commit it */
/* set transaction handle2 into the service handle */
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp2, 0,
OCI_ATTR_TRANS, errhp);
OCITransCommit(svchp, errhp, (ub4) 0);
}

Using OCITransStart() in a Single Session Operating on Multiple Branches Sharing
the Same Transaction
int main()
{
OCIEnv *envhp;
OCIServer *srvhp;
OCIError *errhp;
OCISvcCtx *svchp;
OCISession *usrhp;
OCIStmt *stmthp;
OCITrans *txnhp1, *txnhp2;
void
*tmp;
XID gxid;
text sqlstmt[128];
OCIEnvCreate(&envhp, OCI_DEFAULT, (void *)0, 0, 0, 0,
(size_t)0, (void *)0);
OCIHandleAlloc( (void *) envhp, (void **) &errhp, (ub4) OCI_HTYPE_ERROR,
52, (void **) &tmp);
OCIHandleAlloc( (void *) envhp, (void **) &srvhp, (ub4) OCI_HTYPE_SERVER,
52, (void **) &tmp);
OCIServerAttach( srvhp, errhp, (text *) 0, (sb4) 0, (ub4) OCI_DEFAULT);
OCIHandleAlloc( (void *) envhp, (void **) &svchp, (ub4) OCI_HTYPE_SVCCTX,
52, (void **) &tmp);
OCIHandleAlloc((void *)envhp, (void **)&stmthp, OCI_HTYPE_STMT, 0, 0);

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OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)srvhp, 0,
OCI_ATTR_SERVER, errhp);
/* set the external name and internal name in server handle */
OCIAttrSet((void *)srvhp, OCI_HTYPE_SERVER, (void *) "demo", 0,
OCI_ATTR_EXTERNAL_NAME, errhp);
OCIAttrSet((void *)srvhp, OCI_HTYPE_SERVER, (void *) "txn demo2", 0,
OCI_ATTR_INTERNAL_NAME, errhp);
/* allocate a user context handle */
OCIHandleAlloc((void *)envhp, (void **)&usrhp, (ub4) OCI_HTYPE_SESSION,
(size_t) 0, (void **) 0);
OCIAttrSet((void *)usrhp, (ub4)OCI_HTYPE_SESSION, (void *)"HR",
(ub4)strlen("HR"), OCI_ATTR_USERNAME, errhp);
OCIAttrSet((void *)usrhp, (ub4)OCI_HTYPE_SESSION, (void *)"HR",
(ub4)strlen("HR"),OCI_ATTR_PASSWORD, errhp);
OCISessionBegin (svchp, errhp, usrhp, OCI_CRED_RDBMS, 0);
OCIAttrSet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX,
(void *)usrhp, (ub4)0, OCI_ATTR_SESSION, errhp);
/* allocate transaction handle 1 and set it in the service handle */
OCIHandleAlloc((void *)envhp, (void **)&txnhp1, OCI_HTYPE_TRANS, 0, 0);
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp1, 0,
OCI_ATTR_TRANS, errhp);
/* start a transaction with global transaction id = [1000, 123, 1] */
gxid.formatID = 1000; /* format id = 1000 */
gxid.gtrid_length = 3; /* gtrid = 123 */
gxid.data[0] = 1; gxid.data[1] = 2; gxid.data[2] = 3;
gxid.bqual_length = 1; /* bqual = 1 */
gxid.data[3] = 1;
OCIAttrSet((void *)txnhp1, OCI_HTYPE_TRANS, (void *)&gxid, sizeof(XID),
OCI_ATTR_XID, errhp);
/* start global transaction 1 with 60-second time to live when detached */
OCITransStart(svchp, errhp, 60, OCI_TRANS_NEW);
/* update hr.employees employee_id=7902, increment salary */
sprintf((char *)sqlstmt, "UPDATE EMPLOYEES SET SALARY = SALARY + 1 \
WHERE EMPLOYEE_ID = 7902");
OCIStmtPrepare(stmthp, errhp, sqlstmt, strlen((char *)sqlstmt),
OCI_NTV_SYNTAX, 0);
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, 0, 0, 0);
/* detach the transaction */
OCITransDetach(svchp, errhp, 0);
/* allocate transaction handle 2 and set it in the service handle */
OCIHandleAlloc((void *)envhp, (void **)&txnhp2, OCI_HTYPE_TRANS, 0, 0);
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp2, 0,
OCI_ATTR_TRANS, errhp);
/*
/*
/*
/*
/*

start a transaction with global transaction id = [1000, 123, 2] */
The global transaction is tightly coupled with earlier transactions */
There is not much practical value in doing this but the example */
illustrates the use of tightly coupled transaction branches. */
In a practical case, the second transaction that tightly couples with */

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/* the first can be executed from a different process/thread. */
gxid.formatID = 1000; /* format id = 1000 */
gxid.gtrid_length = 3; /* gtrid = 123 */
gxid.data[0] = 1; gxid.data[1] = 2; gxid.data[2] = 3;
gxid.bqual_length = 1; /* bqual = 2 */
gxid.data[3] = 2;
OCIAttrSet((void *)txnhp2, OCI_HTYPE_TRANS, (void *)&gxid,
sizeof(XID), OCI_ATTR_XID, errhp);
/* start global transaction 2 with 90-second time to live when detached */
OCITransStart(svchp, errhp, 90, OCI_TRANS_NEW);
/* update hr.employees employee_id=7902, increment salary */
/* This is possible even if the earlier transaction has locked this row */
/* because the two global transactions are tightly coupled */
OCIStmtExecute(svchp, stmthp, errhp, 1, 0, 0, 0, 0);
/* detach the transaction */
OCITransDetach(svchp, errhp, 0);
/* Resume transaction 1 and prepare it. This returns */
/* OCI_SUCCESS_WITH_INFO because all branches except the last branch */
/* are treated as read-only transactions for tightly coupled transactions */
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp1, 0,
OCI_ATTR_TRANS, errhp);
if (OCITransPrepare(svchp, errhp, (ub4) 0) == OCI_SUCCESS_WITH_INFO)
{
text errbuf[512];
ub4 buflen;
sb4 errcode;
OCIErrorGet ((void *) errhp, (ub4) 1, (text *) NULL, &errcode,
errbuf, (ub4) sizeof(errbuf), (ub4) OCI_HTYPE_ERROR);
printf("OCITransPrepare - %s\n", errbuf);
}
/* attach to transaction 2 and commit it */
/* set transaction handle2 into the service handle */
OCIAttrSet((void *)svchp, OCI_HTYPE_SVCCTX, (void *)txnhp2, 0,
OCI_ATTR_TRANS, errhp);
OCITransCommit(svchp, errhp, (ub4) 0);
}

Related Topics
•

OCITransDetach()
Detaches a global transaction.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.8 Sharding Functions
Lists the sharding functions.
The following table lists the sharding OCI functions that are described in this section.

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Table 26-7

Sharding Functions

Function

Purpose

OCIShardingKeyColumnAdd()

Adds sharding key columns to form a
compound sharding key or a compound super
sharding key.

OCIShardingKeyReset()

Resets an already created sharding key or
super sharding key for reuse with new key
column values.

OCIShardInstancesGet()

Returns instance names for a given sharding
key descriptor, super sharding key descriptor,
and connection string.

26.8.1 OCIShardingKeyColumnAdd()
Adds sharding key columns to form a compound sharding key or a compound super
sharding key.
Purpose
Adds sharding key columns to form a compound sharding key or a compound super
sharding key. A sharding key column is a column in a table that is used as the key. If
there are multiple columns to be used as the key then it is a compound key.
Syntax
sword OCIShardingKeyColumnAdd(OCIShardingKey
OCIError
void
ub4
ub2
ub4

*shardingKey,
*errhp,
*col,
colLen,
colType,
mode);

Parameters
shardingKey (IN)
The sharding key or super sharding key.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information in the
event of an error.
col (IN)
The sharding key column, a component of the compound key. For character strings,
the values are assumed to be in the client character set (specified by NLS_LANG or the
OCIEnvNLSCreate() call).
colLen (IN)
Length of the sharding key column.
colType (IN)
The data type of the column.

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mode (IN)
OCI_DEFAULT is the only value supported.

Returns
OCI_SUCCESS or OCI_ERROR

Usage Notes
Users must allocate an OCIShardingKey descriptor.
Call OCIShardingKeyColumnAdd() as many times as there are columns in the compound
key (one time for a simple sharding key), in the order in which the key is defined in the
database. The colType variable indicates the data type of the column.
The following table shows the supported OCI data type values for the colType
parameter and its corresponding C data type.
OCI Data Type

C Data Type

SQLT_NUM

ub1*

SQLT_CHR

OraText*

SQLT_DATE

ub1*

SQLT_TIMESTAMP

OCIDateTime*

SQLT_RAW

ub1*

SQLT_VNU

ub1*

SQLT_INT

int*

Examples
Example 26-1

Creating a Compound Sharding Key

Use the OCIShardingKey descriptor for the sharding key, then allocate a descriptor and
call OCIShardingKeyColumnAdd() as many times as needed to create the compound
sharding key.
OCIShardingKey *shardKey;
text *name = “KK”;
int empid = 150;
checker(&status, errhp, OCIDescriptorAlloc(envhp,(dvoid **)&shardKey,
OCI_DTYPE_SHARDING_KEY, 0,(dvoid **)0)));
/* construct a compound key */
OCIShardingKeyColumnAdd(shardKey, OCIError *errhp,(ub4*)&empid, sizeof(empid),
SQLT_INT, OCI_DEFAULT);
OCIShardingKeyColumnAdd(shardKey, OCIError *errhp, name, strlen(name),
SQLT_CHR, OCI_DEFAULT));

Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCISessionPoolCreate()
Initializes a session pool for use with OCI session pooling and database resident
connection pooling (DRCP).

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26.8.2 OCIShardingKeyReset()
Resets an already created sharding key or super sharding key for reuse with new key
column values.
Purpose
A sharding key or super sharding key descriptor can be reset using this routine, which
removes all the key column values added prior to this call. After this call, the descriptor
can be used to set new key column values.
Syntax
sword OCIShardingKeyReset(OCIShardKey *shardKey,
OCIError
*errhp,
ub4
mode);

Parameters
shardKey(IN)
The sharding key or super sharding key descriptor.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in the event
of an error.
mode (IN)
OCI_DEFAULT is the only value currently supported.

Returns
OCI_SUCCESS or OCI_ERROR

Usage Notes
None.
Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIAttrGet()
Gets the value of an attribute of a handle.

26.8.3 OCIShardInstancesGet()
For use with custom pools only, gets the instance names given a sharding key
descriptor, super sharding key descriptor, and a connection string.
Purpose
For use with custom pools only, returns instance names for a given sharding key
descriptor for a chunk and super sharding key descriptor for a group of chunks and a
connection string. Shards are locations in a set of databases where each database
stores some part of the data. The part of the data stored at each database is

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represented by a set of chunks, where each chunk is associated with a certain range
of the data.
Syntax
sword OCIShardInstancesGet(
void
**shTopoCtx,
OCIError
*errhp,
const OraText
*connstr,
ub4
constrl,
OCIShardingKey *shardingKey,
OCIShardingKey *superShardingKey,
OCIShardinst ***shardinsts,
ub4
numShardInsts,
ub4
mode);

Parameters
shTopoCtx(IN/OUT)
An opaque context that is created by OCI and returned in the first call to this method
for a given connect string. This is an optional parameter and can be passed as NULL.
For better performance, pass the void * shardTopoCtx returned from a prior call (if
any) to OCIShardInstancesGet() for the same connection string.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in the event
of an error.
connstr (IN)
The original connect string passed by the application to the OCISessionGet() call.
connstrl(IN)
Length of the connstr parameter.
shardingKey (IN)
The sharding key for the desired chunk.
superShardingKey (IN)
The super sharding key for the desired chunk; this value can be NULL.
shardInsts(OUT)
An array of OCIShardInst descriptors corresponding to instances that serve the chunk
associated with the sharding key and super sharding key.
numShardInsts(OUT)
The number of elements in shardInsts.
mode(IN)
OCI_DEFAULT is the only value supported.

Returns
OCI_SUCCESS or OCI_ERROR

Usage Notes
None.

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Examples
Example 26-2

Custom Pool Example

This example uses a custom pool and illustrates how to get the instance name of a
given connection and how to look up for instances hosting a given sharding key, shard
name, and super sharding name for a given connection. If there is no matching
connection in the custom pool, it creates a new connection.
OCIShardInstancesGet(
&shTopoCtx,
errhp,
connstr,
strlen(connstrl),
shardingKey,
superShardingKey,
&shardInsts,
&numShardInsts,
OCI_DEFAULT);
/* Iterate through all the shard instances that have the data satisfying the
sharding key. */
for (k=0; k < numShardInsts; k++ )
{
OCIAttrGet(shardInstances[k],
(ub4) OCI_DTYPE_SHARD_INST,
(dvoid *)&iName,
(ub4 *)&inameLen,
OCI_ATTR_INSTNAME,
(OCIError *)errhp);
/* Look up in the custom pool for a connection to the same shard instance. */
/* The following attribute can be used to find the instance name. */
OCIAttrGet(svchp[i],
OCI_HTYPE_SVCCTX,
&cshardName[i],
(ub4 *) &cshardNameLen[i],
OCI_ATTR_INSTNAME, errhp);
/* If a matching connection is found (iName and cshardName[i]). */
{
OCIAttrSet(svchp[i],
OCI_HTYPE_SVCCTX,
shardingKey,
sizeof(shardingKey),
OCI_ATTR_SHARDING_KEY,
errhp);
/* Return that connection to the requester. */
return svchp[i];
}
}
/* If no free existing connection is found, create a new connection in the pool and
return it. */
{
OCIAttrSet(authp,

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OCI_HTYPE_AUTHINFO,
shardingKey,
sizeof(shardingKey),
OCI_ATTR_SHARDING_KEY,
errhp);
OCISessionGet ((OCIEnv *)envhp,
(OCIError *)errhp,
(OCISvcCtx **)&mysvc,
(OCIAuthInfo *)authp,
(OraText *)connstr,
(ub4)strlen((char*)connstrl),
(OraText *)NULL, (ub4)0,
(OraText **)0, (ub4 *)0,
(boolean *)0,OCI_SESSGET_CUSTOM_POOL);
return mysvc; /* Track in the pool too. */
}

Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIAttrGet()
Gets the value of an attribute of a handle.

•

OCISessionGet()
Gets a session.

26.9 Miscellaneous Functions
Lists and describes the miscellaneous OCI functions.
Table 26-8 lists the miscellaneous OCI functions that are described in this section.
Table 26-8

Miscellaneous Functions

Function

Purpose

OCIBreak()

Perform an immediate asynchronous break

OCIClientVersion()

Return the client library version

OCIErrorGet()

Return error message and Oracle error

OCILdaToSvcCtx()

Toggle Lda_Def to service context handle

OCIPasswordChange()

Change password

OCIPing()

Confirm that the connection and the server are
active

OCIReset()

Call after OCIBreak() to reset asynchronous
operation and protocol

OCIRowidToChar()

Convert a Universal ROWID to character extended
(base 64) representation

OCIServerRelease()

Get the Oracle release string

OCIServerVersion()

Get the Oracle version string

OCISvcCtxToLda()

Toggle service context handle to Lda_Def

OCIUserCallbackGet()

Identify the callback that is registered for handle

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Table 26-8

(Cont.) Miscellaneous Functions

Function

Purpose

OCIUserCallbackRegister()

Register a user-created callback function

26.9.1 OCIBreak()
Performs an immediate asynchronous break.
Purpose
Performs an immediate (asynchronous) termination of any currently executing OCI
function that is associated with a server.
Syntax
sword OCIBreak ( void
OCIError

*hndlp,
*errhp );

Parameters
hndlp (IN/OUT)
The service context handle or the server context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
This call performs an immediate (asynchronous) termination of any currently executing
OCI function that is associated with a server. It is normally used to stop a long-running
OCI call being processed on the server. It can be called by a user thread in
multithreaded applications, or by a user signal handler on Linux or UNIX systems.
OCIBreak() is the only OCI call allowed in a user signal handler.

Note:
OCIBreak() works on Windows systems, including Windows 2000 and

Windows XP.

This call can take either the service context handle or the server context handle as a
parameter to identify the function to be terminated.
Related Topics
•

OCIReset()
Resets the interrupted asynchronous operation and protocol.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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•

Server Handle Attributes
Lists and describes server handle attributes.

•

Nonblocking Mode in OCI
OCI provides the ability to establish a server connection in blocking mode or
nonblocking mode.

•

About Canceling Calls
How do you cancel long-running or repeated OCI calls.

26.9.2 OCIClientVersion()
Returns the client library version.
Purpose
Returns the 5 digit Oracle Database version number of the client library at run time.
Syntax
void OCIClientVersion ( sword
sword
sword
sword
sword

*featureRelease,
*releaseUpdate,
*releaseUpdateRevision,
*increment,
*ext );

Parameters
featureRelease (OUT)
The feature release year.
releaseUpdate (OUT)
The release update number.
releaseUpdateRevision (OUT)
The release update revision number.
increment (OUT)
The release update increment number.
ext (OUT)
The extension number.
Comments
Beginning with release 18c, version 18.1, there are five new client macros for
extracting each of the components of the database version. These macros are
intended to be used in conjunction with the encoded database version number
returned by OCIServerRelease2() to extract each of the 5 components of the database
version. These macros are named according to the new release naming scheme
started with version 18.1. The 5 digits extracted from the version number are: ..... For example, 18.1.1.1.1 would represent feature release 18,

release update 1, release update revision 1, release update increment 1, extension
1.featureRelease() returns the feture release year of OCI client that the application is
running with. This is useful for the application to know at run time. An application or a
test program can determine the version and the patch set of a particular OCI client

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installation by calling this function. This is also useful if the application wants to have
different codepaths depending upon the level of the client patchset.
These macros are useful for writing a generic application that can be built and run with
different versions of OCI client. For example:
....
#if (featureRelease > 12)
...
#endif
....

Even though the naming is based on the new convention, for convenience, the same
macros can be used to extract the corresponding 5 components of the database
version from an encoded version number returned by OCIServerRelease() from a pre
version 18.1 database, which used a different encoding scheme. In that case though,
the components correspond to the following:
•

Version number

•

Release number

•

Update number

•

Porting release number

•

Porting update number

Related Topics
•

OCIServerRelease()
Returns the Oracle Database release string.

26.9.3 OCIErrorGet()
Returns an error message and an Oracle Database error code.
Purpose
Returns an error message in the buffer provided and an Oracle Database error code.
Syntax
sword OCIErrorGet ( void
ub4
OraText
sb4
OraText
ub4
ub4

*hndlp,
recordno,
*sqlstate,
*errcodep,
*bufp,
bufsiz,
type );

Parameters
hndlp (IN)
The error handle, usually, or the environment handle (for errors on OCIEnvCreate(),
OCIHandleAlloc()).
recordno (IN)
Indicates the status record from which the application seeks information. Starts from
1.

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sqlstate (OUT)
Not supported in release 8.x or later.
errcodep (OUT)
The error code returned.
bufp (OUT)
The error message text returned.
bufsiz (IN)
The size of the buffer provided for the error message, in number of bytes. If the error
message length is more than bufsiz, a truncated error message text is returned in
bufp.
If type is set to OCI_HTYPE_ERROR, then the return code during truncation for
OCIErrorGet() is OCI_ERROR. The client can then specify a bigger buffer and call
OCIErrorGet() again.
If bufsiz is sufficient to hold the entire message text and the message could be
successfully copied into bufp, the return code for OCIErrorGet() is OCI_SUCCESS.
Use one of the following constants to define the error message buffers into which you
get the returned message back from OCIErrorGet():
# define OCI_ERROR_MAXMSG_SIZE 1024 /* max size of an error message */
# define OCI_ERROR_MAXMSG_SIZE2 3072 /* new length max size of an error message */

You should use OCI_ERROR_MAXMSG_SIZE2 to ensure you get more information in the
returned error text.
For example, you can do the following:
char errorMesg[OCI_ERROR_MAXMSG_SIZE2];

Then pass this buffer into OCIErrorGet(). You also need to pass the same
OCI_ERROR_MAXMSG_SIZE2 value into the OCIErrorGet() call to indicate the size of the
buffer that you have allocated.
type (IN)
The type of the handle (OCI_HTYPE_ERROR or OCI_HTYPE_ENV).
Comments
This function does not support SQL statements. Usually, hndlp is actually the error
handle, or the environment handle. You should always get the message in the
encoding that was set in the environment handle.
Note that if OCIErrorGet() is called following an OCI call that does not return an
OCI_ERROR or OCI_SUCCESS_WITH_INFO, then an error message from some earlier OCI call
that resulted in an error may be found by OCIErrorGet(). To avoid this issue,
OCIErrorGet() should only be called following OCI calls that return either OCI_ERROR or
OCI_SUCCESS_WITH_INFO.
The error handle is originally allocated with a call to OCIHandleAlloc().

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Note:
The OCIErrorGet() function returns at least one single diagnostic record.
Multiple diagnostic records can be retrieved by calling the OCIErrorGet()
method repeatedly, until there are no more records and the method returns
OCI_NO_DATA.

See Also:
Error Handling in OCI

Example
The following code example shows a simplified example of a function for error
checking using OCIErrorGet().
Using OCIErrorGet() for Error Checking
static void checkerr(OCIError *errhp, sword status)
{
text errbuf[512];
ub4 buflen;
sb4 errcode;
if (status == OCI_SUCCESS) return;
switch (status)
{
case OCI_SUCCESS_WITH_INFO:
printf("Error - OCI_SUCCESS_WITH_INFO\n");
OCIErrorGet ((void *) errhp, (ub4) 1, (text *) NULL, &errcode,
errbuf, (ub4) sizeof(errbuf), (ub4) OCI_HTYPE_ERROR);
printf("Error - %s\n", errbuf);
break;
case OCI_NEED_DATA:
printf("Error - OCI_NEED_DATA\n");
break;
case OCI_NO_DATA:
printf("Error - OCI_NO_DATA\n");
break;
case OCI_ERROR:
OCIErrorGet ((void *) errhp, (ub4) 1, (text *) NULL, &errcode,
errbuf, (ub4) sizeof(errbuf), (ub4) OCI_HTYPE_ERROR);
printf("Error - %s\n", errbuf);
break;
case OCI_INVALID_HANDLE:
printf("Error - OCI_INVALID_HANDLE\n");
break;
case OCI_STILL_EXECUTING:
printf("Error - OCI_STILL_EXECUTING\n");
break;
case OCI_CONTINUE:
printf("Error - OCI_CONTINUE\n");
break;
default:

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printf("Error - %d\n", status);
break;
}
}

Related Topics
•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

26.9.4 OCILdaToSvcCtx()
Converts a V7 Lda_Def to a V8 or later service context handle.
Purpose
Converts a V7 Lda_Def to a V8 or later service context handle.
Syntax
sword OCILdaToSvcCtx ( OCISvcCtx **svchpp,
OCIError
*errhp,
Lda_Def
*ldap );

Parameters
svchpp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
ldap (IN/OUT)
The Oracle7 logon data area returned by OCISvcCtxToLda() from this service context.
Comments
Converts an Oracle7 Lda_Def to a release 8 or later service context handle. The action
of this call can be reversed by passing the resulting service context handle to the
OCISvcCtxToLda() function.
You should use the OCILdaToSvcCtx() call only for resetting an Lda_Def obtained from
OCISvcCtxToLda() back to a service context handle. It cannot be used to transform an
Lda_def that started as an Lda_def back to a service context handle.
If the service context has been converted to an Lda_Def, only Oracle7 calls can be
used. It is illegal to make OCI release 8 or later calls without first resetting the Lda_Def
to a service context.
The OCI_ATTR_IN_V8_MODE attribute of the server handle or service context handle
enables an application to determine whether the application is currently in Oracle
release 7 mode or Oracle release 8 or later mode.

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Related Topics
•

OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Handler and Descriptor Attributes
Describes the attributes for OCI handles and descriptors.

26.9.5 OCIPasswordChange()
Changes the password of an account.
Purpose
Allows the password of an account to be changed.
Syntax
sword OCIPasswordChange ( OCISvcCtx
OCIError
const OraText
ub4
const OraText
ub4
const OraText
sb4
ub4

*svchp,
*errhp,
*user_name,
usernm_len,
*opasswd,
opasswd_len,
*npasswd,
npasswd_len,
mode );

Parameters
svchp (IN/OUT)
A handle to a service context. The service context handle must be initialized and have
a server context handle associated with it.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
user_name (IN)
Specifies the user name, which can be in UTF-16 encoding. It must be terminated
with a NULL character if the service context has been initialized with an authentication
handle.
usernm_len (IN)
The length of the user name string specified in user_name, in number of bytes
regardless of the encoding. The usernm_len value must be nonzero.
opasswd (IN)
Specifies the user's old password, which can be in UTF-16 encoding.
opasswd_len (IN)
The length of the old password string specified in opasswd, in bytes. The opasswd_len
value must be nonzero.

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npasswd (IN)
Specifies the user's new password, which can be in UTF-16 encoding. If the password
complexity verification routine is specified in the user's profile to verify the new
password's complexity, the new password must meet the complexity requirements of
the verification function.
npasswd_len (IN)
The length in bytes of the new password string specified in npasswd. For a valid
password string, npasswd_len must be nonzero.
mode (IN)
OCI_DEFAULT - Use the setting in the environment handle.

•

OCI_UTF16 - Use UTF-16 encoding, regardless of the setting of the environment

handle.
There is only one encoding allowed, either UTF-16 or not, for user_name, opasswd,
and npasswd.
•

OCI_AUTH - If a user session context is not created, a call with this flag creates the

user session context and changes the password. At the end of the call, the user
session context is not cleared. Hence the user remains logged in.
If the user session context is created, a call with this flag only changes the
password and has no effect on the session. Hence the user still remains logged
in.
The OCI_AUTH mode can be used with any of the OCI_CPW_* modes listed in this
section to establish the respective administrative session for the expired user
account at logon before changing the password.
•

OCI_CPW_SYSDBA — In this mode, you are authenticated for SYSDBA access.

•

OCI_CPW_SYSOPER — In this mode, you are authenticated for SYSOPER access.

•

OCI_CPW_SYSASM — In this mode, you are authenticated for SYSASM access.

•

OCI_CPW_SYSBKP — In this mode, you are authenticated for SYSBKP access.

•

OCI_CPW_SYSDGD — In this mode, you are authenticated for SYSDGD access.

•

OCI_CPW_SYSKMT — In this mode, you are authenticated for SYSKMT access.

Comments
This call allows the password of an account to be changed. This call is similar to
OCISessionBegin() with the following differences:
•

If the user session is established, this call authenticates the account using the old
password and then changes the password to the new password.

•

If the user session is not established, this call establishes a user session and
authenticates the account using the old password, and then changes the
password to the new password.

This call is useful when the password of an account has expired and OCISessionBegin()
returns an error (ORA-28001) or warning that indicates that the password has expired.
The mode or the environment handle determines if UTF-16 is being used.
For a Release 12.1 or later client password change with a Release 11.2 server, you
must first call OCISessionBegin() before calling OCIPasswordChange(); otherwise the
password change operation fails with an ORA-1017 error.

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Related Topics
•

OCISessionBegin()
Creates a user session and begins a user session for a given server.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.9.6 OCIPing()
Confirms that the connection and the server are active.
Purpose
Makes a round-trip call to the server to confirm that the connection and the server are
active.
Syntax
sword OCIPing ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
mode );

Parameters
svchp (IN)
A handle to a service context. The service context handle must be initialized and have
a server context handle associated with it.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
mode (IN)
The mode for the call. Use OCI_DEFAULT.
Comments
OCIPing() makes a dummy round-trip call to the server; that is, a dummy packet is sent
to the server for response. OCIPing() returns after the round-trip is completed. No

server operation is performed for this call itself.
You can use OCIPing() to make a lightweight call to the server. A successful return of
the call indicates that the connection and server are active. If the call blocks, the
connection may be in use by other threads. If it fails, there may be some problem with
the connection or the server, and the error can be retrieved from the error handle.
Because OCIPing() is a round-trip call, you can also use it to flush all the pending OCI
client-side calls to the server, if any exist. For example, calling OCIPing() after
OCIHandleFree() can force the execution of the pending call to close back-end cursors.
The call is useful when the application requires the back-end cursors to be closed
immediately, which otherwise would be closed in the next round-trip on that
connection. Also, with the enhanced functionality of OCI_ATTR_SERVER_STATUS, OCIPing
may not be needed if the requirement is just to check the health of the connection. See
the OCI_ATTR_SERVER_STATUS attribute in Server Handle Attributes for more information.
Related Topics
•

OCIHandleFree()
Explicitly deallocates a handle

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.9.7 OCIReset()
Resets the interrupted asynchronous operation and protocol.
Purpose
Must be called if an OCIBreak() call was issued while a nonblocking operation was in
progress.
Syntax
sword OCIReset ( void
OCIError

*hndlp,
*errhp );

Parameters
hndlp (IN)
The service context handle or the server context handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
This call is called in nonblocking mode only. It resets the interrupted asynchronous
operation and protocol. OCIReset() must be called if an OCIBreak() call was issued
while a nonblocking operation was in progress.
Related Topics
•

OCIBreak()
Performs an immediate asynchronous break.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.9.8 OCIRowidToChar()
Converts a Universal ROWID to character extended (base 64) representation.
Purpose
Converts a Universal ROWID to character extended (base 64) representation.
Syntax
sword OCIRowidToChar ( OCIRowid
OraText
ub2
OCIError

*rowidDesc,
*outbfp,
*outbflp
*errhp );

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Parameters
rowidDesc (IN)
The ROWID descriptor that is allocated by OCIDescriptorAlloc() and populated by a
prior execution of a SQL statement.
outbfp (OUT)
Pointer to the buffer where the character representation is stored after successful
execution of this call.
outbflp (IN/OUT)
Pointer to the output buffer length. Before execution, the buffer length contains the
size of outbfp. After execution it contains the number of bytes converted.
If there is truncation during conversion, outbfp contains the length required to make
conversion successful. An error is also returned.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
Comments
After this conversion, the ROWID in character format can be bound with the
OCIBindByPos() or OCIBindByName() calls, and used to query a row at the given ROWID.
If the environment was created using OCIEnvNlsCreate() with parameters charset and
ncharset set to OCI_UTF16ID, the function OCIRowidToChar() returns the rowid
representation in ASCII, not in UTF-16 as expected.
Related Topics
•

OCIDescriptorAlloc()
Allocates storage to hold descriptors or LOB locators.

•

OCIBindByPos()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByPos2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this call when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIBindByName()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block.

•

OCIBindByName2()
Creates an association between a program variable and a placeholder in a SQL
statement or PL/SQL block. Use this function when working with data types when
actual lengths exceed UB2MAXVAL on the client.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.9.9 OCIServerRelease()
Returns the Oracle Database release string.
Purpose
Returns the Oracle Database release string.
Syntax
sword OCIServerRelease ( void
OCIError
OraText
ub4
ub1
ub4

*hndlp,
*errhp,
*bufp,
bufsz
hndltype
*version );

Parameters
hndlp (IN)
The service context handle or the server context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
bufp (IN/OUT)
The buffer in which the release string is returned.
bufsz (IN)
The length of the buffer in number of bytes.
hndltype (IN)
The type of handle passed to the function.
version (IN/OUT)
The release string in integer format.
Comments
The buffer pointer bufp points to the release information in a string representation up to
the bufsz including the NULL terminator. If the buffer size is too small, the result is
truncated to the size bufsz. The version argument contains the 5-digit Oracle Database
release string in integer format, which can be retrieved using the following macros:
#define
#define
#define
#define
#define

MAJOR_NUMVSN(v) ((sword)(((v) >> 24) & 0x000000FF))
MINOR_NUMRLS(v) ((sword)(((v) >> 20) & 0x0000000F))
UPDATE_NUMUPD(v) ((sword)(((v) >> 12) & 0x000000FF))
PORT_REL_NUMPRL(v) ((sword)(((v) >> 8) & 0x0000000F))
PORT_UPDATE_NUMPUP(v) ((sword)(((v) >> 0) & 0x000000FF))

/*
/*
/*
/*
/*

version number */
release number */
update number */
port release number */
port update number */

Related Topics
•

OCIServerVersion()
Returns the Oracle Database version string.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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26.9.10 OCIServerRelease2()
Returns the Oracle Database release string.
Purpose
Returns the Oracle Database release string.
Syntax
sword OCIServerRelease2( void
OCIError
OraText
ub4
ub1
ub4
ub4

*hndlp,
*errhp,
*bufp,
bufsz,
hndltype,
*versionp,
mode );

Parameters
hndlp (IN)
The service context handle or the server context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
bufp (IN/OUT)
The buffer in which the release string is returned.
bufsz (IN)
The length of the buffer in number of bytes.
hndltype (IN)
The type of handle passed to the function.
versionp (IN/OUT)
The release string in integer format.
mode (IN)
The only valid value is OCI_DEFAULT.
Comments
The buffer pointer bufp points to the release information in a string representation up to
the bufsz including the NULL terminator. If the buffer size is too small, the result is
truncated to the size bufsz. The version argument contains the 5-digit Oracle Database
release string in integer format, which can be retrieved using the following macros:
OCI_SERVER_RELEASE_REL(v)
/* old: version number */
/* new: feature release */
OCI_SERVER_RELEASE_REL_UPD(v)
/* old: release number */
/* new: release update */
OCI_SERVER_RELEASE_REL_UPD_REV(v)
/* old: update number */
/* new: release update revision */

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OCI_SERVER_RELEASE_REL_UPD_INC(v)
/* old: porting release number */
/* new: release update increment */
OCI_SERVER_RELEASE_EXT(v)
/* old: porting update number */
/* new: extension */

Old means applicable when connected to a pre-version 18.1 database. New means
applicable when connected to version 18.1 or later database.

26.9.11 OCIServerVersion()
Returns the Oracle Database version string.
Purpose
Returns the Oracle Database version string.
Syntax
sword OCIServerVersion ( void
OCIError
OraText
ub4
ub1

*hndlp,
*errhp,
*bufp,
bufsz
hndltype );

Parameters
hndlp (IN)
The service context handle or the server context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
bufp (IN/OUT)
The buffer in which the version information is returned.
bufsz (IN)
The length of the buffer in number of bytes.
hndltype (IN)
The type of handle passed to the function.
Comments
This call returns the version string of Oracle Database. It can be in Unicode if the
environment handle so determines.
For example, the following is returned in bufp as the version string if an application is
running on an 8.1.5 SunOS server:
Oracle8i Enterprise Edition Release 8.1.5.0.0 - Production
With the Partitioning and Java options
PL/SQL Release 8.1.5.0.0 - Production

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Related Topics
•

OCIClientVersion()
Returns the client library version.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

26.9.12 OCISvcCtxToLda()
Toggles between a V8 or later service context handle and a V7 Lda_Def.
Purpose
Toggles between a V8 or later service context handle and a V7 Lda_Def.
Syntax
sword OCISvcCtxToLda ( OCISvcCtx
OCIError
Lda_Def

*srvhp,
*errhp,
*ldap );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
ldap (IN/OUT)
A Logon Data Area for Oracle7-style OCI calls that is initialized by this call.
Comments
Toggles between an OCI release 8 or later service context handle and an Oracle7
Lda_Def.
This function can only be called after a service context has been properly initialized.
Once the service context has been translated to an Lda_Def, it can be used in release
7.x OCI calls (for example, obindps(), ofen()).
If there are multiple service contexts that share the same server handle, only one can
be in Oracle7 mode at any time.
The action of this call can be reversed by passing the resulting Lda_Def to the
OCILdaToSvcCtx() function.
The OCI_ATTR_IN_V8_MODE attribute of the server handle or service context handle
enables an application to determine whether the application is currently in Oracle
release 7 mode or Oracle release 8 or later mode.
Related Topics
•

OCILdaToSvcCtx()
Converts a V7 Lda_Def to a V8 or later service context handle.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Handler and Descriptor Attributes
Describes the attributes for OCI handles and descriptors.

26.9.13 OCIUserCallbackGet()
Determines the callback that is registered for a handle.
Purpose
Determines the callback that is registered for a handle.
Syntax
sword OCIUserCallbackGet ( void
*hndlp,
ub4
type,
void
*ehndlp,
ub4
fcode,
ub4
when,
OCIUserCallback (*callbackp)
(
void *ctxp,
void *hndlp,
ub4
type,
ub4
fcode,
ub1
when,
sword returnCode,
ub4
*errnop,
va_list arglist
),
void
**ctxpp,
OCIUcb *ucbDesc );

Parameters
hndlp (IN)
This is the handle whose type is specified by the type parameter.
type (IN)
The handle type. The valid handle type is OCI_HTYPE_ENV. The callback is registered for
all calls of the function specified by fcode made on the environment handle.
ehndlp (IN)
The OCI error or environment handle. If there is an error, it is recorded in ehndlp, and
this function returns OCI_ERROR. Diagnostic information can be obtained by calling
OCIErrorGet().
fcode (IN)
A unique function code of an OCI function. These are listed in Table 26-9.
when (IN)
Defines when the callback is invoked. Valid modes are:
•

OCI_UCBTYPE_ENTRY - The callback is invoked on entry into the OCI function.

•

OCI_UCBTYPE_EXIT - The callback is invoked before exit from the OCI function.

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•

OCI_UCBTYPE_REPLACE - If it returns anything other than an OCI_CONTINUE, then the

next replacement callback and the OCI code for the OCI function are not called.
Instead, processing jumps to the exit callbacks. For information about this
parameter, see OCIUserCallbackRegister().
callbackp (OUT)
A pointer to a callback function pointer. This returns the function that is currently
registered for these values of fcode, when, and hndlp. The value returned would be NULL
if no callback is registered for this case.

See Also:
OCIUserCallbackRegister() for information about the parameters of callbackp

ctxpp (OUT)
A pointer to return context for the currently registered callback.
ucbDesc (IN)
A descriptor provided by OCI. This descriptor is passed by OCI in the environment
callback. It contains the priority at which the callback would be registered. If the
ucbDesc parameter is specified as NULL, then this callback has the highest priority.
User callbacks registered statically (as opposed to those registered dynamically in a
package) use a NULL descriptor because they do not have a ucb descriptor to use.
Comments
This function discovers or detects what callback is registered for a particular handle.
Related Topics
•

OCIUserCallbackRegister()
Registers a user-created callback function.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Restrictions on Callback Functions
Details the restrictions on callback functions.

26.9.14 OCIUserCallbackRegister()
Registers a user-created callback function.
Purpose
Registers a user-created callback function.
Syntax
sword OCIUserCallbackRegister ( void
*hndlp,
ub4
type,
void
*ehndlp,
OCIUserCallback (callback)
(
void
*ctxp,
void
*hndlp,
ub4
type,

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ub4
ub1
sword
ub4
va_list
void
ub4
ub4
OCIUcb

fcode,
when,
returnCode,
*errnop,
arglist

),
*ctxp,
fcode,
when,
*ucbDesc );

Parameters
hndlp (IN)
This is the handle whose type is specified by the type parameter.
type (IN)
The handle type. The valid handle type is OCI_HTYPE_ENV. The callback is registered for
all calls of the function specified by fcode made on the environment handle.
ehndlp (IN)
The OCI error or environment handle. If there is an error, it is recorded in ehndlp and
this function returns OCI_ERROR. Diagnostic information can be obtained by calling
OCIErrorGet(). Because an error handle is not available within OCIEnvCallback, the
environment handle is passed in as a ehndlp.
callback (IN)
A callback function pointer. The variable argument list in the OCIUserCallback function
prototype are the parameters passed to the OCI function. The typedef for
OCIUserCallback is described later.
If an entry callback returns anything other than OCI_CONTINUE, then the return code is
passed to the subsequent entry or replacement callback, if there is one. If this is the
last entry callback and there is no replacement callback, then the OCI code is
executed and the return code is ignored.
If a replacement callback returns anything other than OCI_CONTINUE, then subsequent
replacement callbacks and the OCI code are bypassed, and processing jumps to the
exit callbacks.
If the exit callback returns anything other than OCI_CONTINUE, then that returned value
is returned by the OCI function; otherwise, the return value from the OCI code or the
replacement callback (if the replacement callback did not return OCI_CONTINUE and
essentially bypassed the OCI code) is returned by the call.
If a NULL value is passed in for callback, then the callback is removed for the when
value and the specified handle. This is the way to deregister a callback for a given
ucbDesc value, including the NULL ucbDesc.
ctxp (IN)
A context pointer for the callback.
fcode (IN)
A unique function code of an OCI function. These are listed in Table 26-9.
when (IN)
Defines when the callback is invoked. Valid modes are:
•

OCI_UCBTYPE_ENTRY - The callback is invoked on entry into the OCI function.

•

OCI_UCBTYPE_EXIT - The callback is invoked before exit from the OCI function.

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•

OCI_UCBTYPE_REPLACE - If the callback returns anything other than OCI_CONTINUE, then

the next replacement callback and the OCI code for the OCI function is not called.
Instead, processing jumps to the exit callbacks.
ucbDesc (IN)
A descriptor provided by OCI. This descriptor is passed by OCI in the environment
callback. It contains the priority at which the callback would be registered. If the
ucbDesc parameter is specified as NULL, then this callback has the highest priority.
User callbacks registered statically (as opposed to those registered dynamically in a
package) use a NULL descriptor as they do not have a ucb descriptor to use.
Comments
This function is used to register a user-created callback with the OCI environment.
Such callbacks allow an application to:
•

Trace OCI calls for debugging and performance measurements

•

Perform additional pre-processing or post-processing after selected OCI calls

•

Substitute the body of a given function with proprietary code to execute on a
foreign data source

The OCI supports: entry callbacks, replacement callbacks, and exit callbacks.
The three types of callbacks are identified by the modes OCI_UCBTYPE_ENTRY,
OCI_UCBTYPE_REPLACE, and OCI_UCBTYPE_EXIT.

The control flow now is:
1.

Execute entry callbacks.

2.

Execute replacement callbacks.

3.

Execute OCI code.

4.

Execute exit callbacks.

Entry callbacks are executed when a program enters an OCI function.
Replacement callbacks are executed after entry callbacks. If the replacement callback
returns a value of OCI_CONTINUE, then subsequent replacement callbacks or the normal
OCI-specific code is executed. If the callback returns anything other than OCI_CONTINUE,
then subsequent replacement callbacks and the OCI code do not execute.
After an OCI function successfully executes, or after a replacement callback returns
something other than OCI_CONTINUE, program control transfers to the exit callback (if
one is registered).
If a replacement or exit callback returns anything other than OCI_CONTINUE, then the
return code from the callback is returned from the associated OCI call.
To determine the callback that is registered for the handle, you can use
OCIUserCallbackGet().
The prototype of the OCIUserCallback typedef is:
typedef sword (*OCIUserCallback)
(void
*ctxp,
void
*hndlp,
ub4
type,
ub4
fcode,

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ub4
sword
sb4
va_list

when,
returnCode,
*errnop,
arglist );

The parameters to the OCIUserCallback function prototype are:
ctxp (IN)
The context passed in as ctxp in the register callback function.
hndlp (IN)
This is the handle whose type is specified in the type parameter. It is the handle on
which the callback is invoked. Because only a type of OCI_HTYPE_ENV is allowed, the
environment handle, env, would be passed in here.
type (IN)
The type registered for the hndlp. The valid handle type is OCI_HTYPE_ENV. The callback
is registered for all calls of the function specified by fcode made on the environment
handle.
fcode (IN)
The function code of the OCI call. These are listed in Table 26-9. Note that callbacks
can be registered for only the OCI calls listed in Table 26-3.
when (IN)
The when value of the callback.
returnCode (IN)
This is the return code from the previous callback or the OCI code. For the first entry
callback, OCI_SUCCESS is always passed in. For the subsequent callbacks, the return
code from the OCI code or the previous callback is passed in.
errnop (IN/OUT)
When the first entry callback is called, the input value of *errnop is 0. If the callback is
returning any value other than OCI_CONTINUE, then it must also set an error number in
*errnop. This value is the set in the error handle passed in the OCI call.
For all subsequent callbacks, the input value of *errnop is the value of error number in
the error handle. Therefore, if the previous callback did not return OCI_CONTINUE, then
the out value of *errnop from the previous callback would be the one in the error
handle, and that value would be passed in here to the subsequent callback. If,
however, the previous callback returned OCI_CONTINUE, then whatever value is in the
error handle would be passed in here.
Note that if a non-Oracle error number is returned in *errnop, then a callback must
also be registered for the OCIErrorGet() function to return appropriate text for the error
number.
arglist (IN)
These are the parameters to the OCI call passed in here as variable number of
arguments. They should be dereferenced using va_arg, as illustrated in the user
callback demonstration programs.

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See Also:
OCI Demonstration Programs
Table 26-9 and Table 26-10 list the OCI Function codes and provides the OCI routine
name and its function number.
Table 26-9

OCI Function Codes

#

OCI Routine

#

OCI Routine

#

OCI Routine

1

OCIInitialize

33

OCITransStart

65

OCIDefineByPos

2

OCIHandleAlloc

34

OCITransDetach

66

OCIBindByPos

3

OCIHandleFree

35

OCITransCommit

67

OCIBindByName

4

OCIDescriptorAlloc

36

(not used)

68

OCILobAssign

5

OCIDescriptorFree

37

OCIErrorGet

69

OCILobIsEqual

6

OCIEnvInit

38

OCILobFileOpen

70

OCILobLocatorIsInit

7

OCIServerAttach

39

OCILobFileClose

71

OCILobEnableBuffering

8

OCIServerDetach

40

(not used)

72

OCILobCharSetId

9

(not used)

41

(not used)

73

OCILobCharSetForm

10

OCISessionBegin

42

OCILobCopy

74

OCILobFileSetName

11

OCISessionEnd

43

OCILobAppend

75

OCILobFileGetName

12

OCIPasswordChange

44

OCILobErase

76

OCILogon

13

OCIStmtPrepare

45

OCILobGetLength

77

OCILogoff

14

(not used)

46

OCILobTrim

78

OCILobDisableBuffering

15

(not used)

47

OCILobRead

79

OCILobFlushBuffer

16

(not used)

48

OCILobWrite

80

OCILobLoadFromFile

17

OCIBindDynamic

49

(not used)

81

OCILobOpen

18

OCIBindObject

50

OCIBreak

82

OCILobClose

19

(not used)

51

OCIServerVersion

83

OCILobIsOpen

20

OCIBindArrayOfStruct

52

(not used)

84

OCILobFileIsOpen

21

OCIStmtExecute

53

(not used)

85

OCILobFileExists

22

(not used)

54

OCIAttrGet

86

OCILobFileCloseAll

23

(not used)

55

OCIAttrSet

87

OCILobCreateTemporary

24

(not used)

56

OCIParamSet

88

OCILobFreeTemporary

25

OCIDefineObject

57

OCIParamGet

89

OCILobIsTemporary

26

OCIDefineDynamic

58

OCIStmtGetPieceInfo

90

OCIAQEnq

27

OCIDefineArrayOfStruct

59

OCILdaToSvcCtx

91

OCIAQDeq

28

OCIStmtFetch

60

(not used)

92

OCIReset

29

OCIStmtGetBindInfo

61

OCIStmtSetPieceInfo

93

OCISvcCtxToLda

30

(not used)

62

OCITransForget

94

OCILobLocatorAssign

31

(not used)

63

OCITransPrepare

95

(not used)

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Table 26-9

(Cont.) OCI Function Codes

#

OCI Routine

#

OCI Routine

#

OCI Routine

32

OCIDescribeAny

64

OCITransRollback

96

OCIAQListen

Table 26-10

Continuation of OCI Function Codes from 97 and Higher

#

OCI Routine

#

OCI Routine

#

OCI Routine

97

Reserved

113

OCILobErase2

129

OCILobGetOptions

98

Reserved

114

OCILobGetLength2

130

OCILobSetOptions

99

OCITransMultiPrepare

115

OCILobLoadFromFile2

131

OCILobFragementInsert

100

OCIConnectionPoolCreate

116

OCILobRead2

132

OCILobFragementDelete

101

OCIConnectionPoolDestroy

117

OCILobTrim2

133

OCILobFragementMove

102

OCILogon2

118

OCILobWrite2

134

OCILobFragementReplace

103

OCIRowidToChar

119

OCILobGetStorageLimit

135

OCILobGetDeduplicateRegio
ns

104

OCISessionPoolCreate

120

OCIDBStartup

136

OCIAppCtxSet

105

OCISessionPoolDestroy

121

OCIDBShutdown

137

OCIAppCtxClearAll

106

OCISessionGet

122

OCILobArrayRead

138

OCILobGetContentType

107

OCISessionRelease

123

OCILobArrayWrite

139

OCILobSetContentType

108

OCIStmtPrepare2

124

OCIAQEnqStreaming

109

OCIStmtRelease

125

OCIAQGetReplayInfo

110

OCIAQEnqArray

126

OCIAQResetReplayInfo

111

OCIAQDeqArray

127

OCIArrayDescriptorAlloc

112

OCILobCopy2

128

OCIArrayDescriptorFree

Related Topics
•

OCIUserCallbackGet()
Determines the callback that is registered for a handle.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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27
OCI Navigational and Type Functions
This chapter describes the OCI navigational functions that are used to navigate
through objects retrieved from an Oracle database.
It also contains the descriptions of the functions that are used to obtain type descriptor
objects (TDOs).

See Also:
For code examples, see the demonstration programs included with your
Oracle Database installation. For additional information, see OCI
Demonstration Programs.

This chapter contains these topics:
•

Introduction to the Navigational and Type Functions

•

OCI Flush or Refresh Functions

•

OCI Mark or Unmark Object and Cache Functions

•

OCI Get Object Status Functions

•

OCI Miscellaneous Object Functions

•

OCI Pin, Unpin, and Free Functions

•

OCI Type Information Accessor Functions

27.1 Introduction to the Navigational and Type Functions
In an object navigational paradigm, data is represented as a graph of objects
connected by references.
Objects in the graph are reached by following the references. OCI provides a
navigational interface to objects in an Oracle database. Those calls are described in
this chapter.
The OCI object environment is initialized when the application calls OCIEnvCreate(),
OCIEnvNlsCreate(), or OCIInitialize() (deprecated) in OCI_OBJECT mode.

See Also:
OCI Object-Relational Programming and Object Advanced Topics in OCI for
more information about using the calls in this chapter

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27.1.1 Object Types and Lifetimes
An object instance is an occurrence of a type defined in an Oracle database.
This section describes how an object instance can be represented in OCI. In OCI, an
object instance can be classified based on the type, the lifetime, and referenceability:
•

A persistent object is an instance of an object type. A persistent object resides in a
row of a table in the server and can exist longer than the duration of a session
(connection). Persistent objects can be identified by object references that contain
the object identifiers. A persistent object is obtained by pinning its object
reference.

•

A transient object is an instance of an object type. A transient object cannot exist
longer than the duration of a session, and it is used to contain temporary
computing results. Transient objects can also be identified by references that
contain transient object identifiers.

•

A value is an instance of a user-defined type (object type or collection type) or any
built-in Oracle type. Unlike objects, values of object types are identified by memory
pointers, rather than by references.

A value can be standalone or embedded. A standalone value is usually obtained by
issuing a select statement. OCI also allows the client program to select a row of object
table into a value by issuing a SQL statement. A referenceable object in the database
can be represented as a value that cannot be identified by a reference. A standalone
value can also be an out-of-line attribute in an object, such as VARCHAR or RAW, or an outof-line element in a collection, such as VARCHAR, RAW, or object.
An embedded value is physically included in a containing instance. An embedded
value can be an inline attribute in an object (such as number or nested object), or an
inline element in a collection.
All values are considered to be transient by OCI, which means that OCI does not
support automatic flushing of a value to the database, and the client must explicitly
execute a SQL statement to store a value into the database. Embedded values are
flushed when their containing instances are flushed.
Figure 27-1 shows how instances can be classified according to their type and lifetime.
The type can be an object or the value of an object. The lifetime can be persistent (can
exist longer than the duration of a session) or transient (can exist no long than the
duration of the session).

Figure 27-1

Classification of Instances by Type and Lifetime

Instance

OBJECT

VALUE

Type

Lifetime
PERSISTENT

TRANSIENT

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Introduction to the Navigational and Type Functions

The distinction between various instances is further described in Table 27-1.
Table 27-1

Type and Lifetime of Instances

Characteristic

Persistent Object

Transient Object

Value

Type

object type

object type

object type, built-in,
collection

Maximum Lifetime

until object is deleted

session

session

Referenceable

yes

yes

no

Embeddable

no

no

yes

27.1.2 Terminology
Describes the terminology used.
The remainder of this chapter uses the following terms:
•

An object is generally used to refer to a persistent object, a transient object, a
standalone value of object type, or an embedded value of object type.

•

A referenceable object refers to a persistent object or a transient object.

•

A standalone object refers to a persistent object, a transient object, or a
standalone value of object type.

•

An embedded object refers to a embedded value of object type.

•

An object is dirty if it has been created (newed), marked as updated, or marked as
deleted.

See Also:
Persistent Objects, Transient Objects, and Values for further discussion
of the terms used to refer to different types of objects

27.1.3 Conventions for OCI Functions
Describes the conventions for OCI functions.
See the Conventions for OCI Functions for the conventions used in describing each
function. The entries for each function may also contain the following information:

27.1.4 Return Values
Describes the return values by the function if the function returns something other then
the standard codes.
A description of what value is returned by the function if the function returns something
other then the standard codes listed in Table 27-3.

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27.1.5 Navigational Function Return Values
Describes the navigational function return values.
Table 27-2 lists the values that OCI navigational functions typically return.
Table 27-2

Return Values of Navigational Functions

Return Value

Meaning

OCI_SUCCESS

The operation succeeded.

OCI_ERROR

The operation failed. The specific error can be retrieved by
calling OCIErrorGet() on the error handle passed to the
function.

OCI_INVALID_HANDLE

The OCI handle passed to the function is invalid.

Function-specific return information follows the description of each function in this
chapter. Information about specific error codes returned by each function is presented
in the following section.

See Also:
Error Handling in OCI for more information about return codes and error
handling

27.1.6 Server Round-Trips for Cache and Object Functions
Describes the number of server round-trips required for individual OCI cache and
object functions.
For a table showing the number of server round-trips required for individual OCI cache
and object functions, see Table C-3.

27.1.7 Navigational Function Error Codes
Describes the external Oracle error codes that can be returned by each of the OCI
navigational functions.
Table 27-3 lists the external Oracle error codes that can be returned by each of the
OCI navigational functions. The list following the table identifies what each error
represents.
Table 27-3

OCI Navigational Functions Error Codes

Function

Possible ORA Errors

OCICacheFlush()

24350, 21560, 21705

OCICacheFree()

24350, 21560, 21705

OCICacheRefresh()

24350, 21560, 21705

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Table 27-3

(Cont.) OCI Navigational Functions Error Codes

Function

Possible ORA Errors

OCICacheUnmark()

24350, 21560, 21705

OCICacheUnpin()

24350, 21560, 21705

OCIObjectArrayPin()

24350, 21560

OCIObjectCopy()

24350, 21560, 21705, 21710

OCIObjectExists()

24350, 21560, 21710

OCIObjectFlush()

24350, 21560, 21701, 21703, 21708, 21710

OCIObjectFree()

24350, 21560, 21603, 21710

OCIObjectGetAttr()

21560, 21600, 22305

OCIObjectGetInd()

24350, 21560, 21710

OCIObjectGetObjectRef()

24350, 21560, 21710

OCIObjectGetTypeRef()

24350, 21560, 21710

OCIObjectIsDirty()

24350, 21560, 21710

OCIObjectIsLocked()

24350, 21560, 21710

OCIObjectLock()

24350, 21560, 21701, 21708, 21710

OCIObjectLockNoWait()

24350, 21560, 21701, 21708, 21710

OCIObjectMarkDelete()

24350, 21560, 21700, 21701, 21702, 21710

OCIObjectMarkDeleteByRef()

24350, 21560

OCIObjectMarkUpdate()

24350, 21560, 21700, 21701, 21710

OCIObjectNew()

24350, 21560, 21705, 21710

OCIObjectPin()

24350, 21560, 21700, 21702

OCIObjectPinCountReset()

24350, 21560, 21710

OCIObjectPinTable()

24350, 21560, 21705

OCIObjectRefresh()

24350, 21560, 21709, 21710

OCIObjectSetAttr()

21560, 21600, 22305, 22279, 21601

OCIObjectUnmark()

24350, 21560, 21710

OCIObjectUnmarkByRef()

24350, 21560

OCIObjectUnpin()

24350, 21560, 21710

The ORA errors in Table 27-3 have the following meanings.
•

ORA-21560 - name argument should not be NULL

•

ORA-21600 - path expression too long

•

ORA-21601 - attribute is not an instance of user-defined type

•

ORA-21603 - cannot free a dirtied persistent object

•

ORA-21700 - object does not exist or has been deleted

•

ORA-21701 - invalid object

•

ORA-21702 - object is not instantiated in the cache

•

ORA-21703 - cannot flush an object that is not modified

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•

ORA-21704 - cannot terminate cache or connection without flushing

•

ORA-21705 - service context is invalid

•

ORA-21708 - operations cannot be performed on a transient object

•

ORA-21709 - operations can only be performed on a current object

•

ORA-21710 - invalid pointer or value passed to the function

•

ORA-22279 - cannot perform operation with LOB buffering enabled

•

ORA-22305 - name argument is invalid

•

ORA-24350 - this OCI call is not allowed from external subroutines

27.2 OCI Flush or Refresh Functions
Lists and describes OCI flush or refresh functions.
Table 27-4 describes the OCI flush or refresh functions that are described in this
section.
Table 27-4

Flush or Refresh Functions

Function

Purpose

OCICacheFlush()

Flush modified persistent objects in cache to
server

OCICacheRefresh()

Refresh pinned persistent objects

OCIObjectFlush()

Flush a modified persistent object to the server

OCIObjectRefresh()

Refresh a persistent object

27.2.1 OCICacheFlush()
Flushes modified persistent objects to the server.
Purpose
Flushes modified persistent objects to the server.
Syntax
sword OCICacheFlush ( OCIEnv
OCIError
const OCISvcCtx
void
OCIRef

OCIRef

*env,
*err,
*svc,
*context,
*(*get)
( void
*context,
ub1
*last ),
**ref );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service context.
context (IN) [optional]
Specifies a user context that is an argument to the client callback function get. This
parameter is set to NULL if there is no user context.
get (IN) [optional]
A client-defined function that acts as an iterator to retrieve a batch of dirty objects that
need to be flushed. If the function is not NULL, this function is called to get a reference
of a dirty object. This is repeated until a NULL reference is returned by the client
function or the parameter last is set to TRUE. The parameter context is passed to get()
for each invocation of the client function. This parameter should be NULL if user
callback is not given. If the object that is returned by the client function is not a dirtied
persistent object, the object is ignored.
All the objects that are returned from the client function must be newed or pinned
using the same service context; otherwise, an error is signaled. Note that the cache
flushes the returned objects in the order in which they were marked dirty.
If this parameter is passed as NULL (for example, no client-defined function is
provided), then all dirty persistent objects for the given service context are flushed in
the order in which they were dirtied.
ref (OUT) [optional]
If there is an error in flushing the objects, (*ref) points to the object that is causing the
error. If ref is NULL, then the object is not returned. If *ref is NULL, then a reference is
allocated and set to point to the object. If *ref is not NULL, then the reference of the
object is copied into the given space. If the error is not caused by any of the dirtied
objects, the given REF is initialized to be a NULL reference (OCIRefIsNull(*ref) is TRUE).
The REF is allocated for session duration (OCI_DURATION_SESSION). The application can
free the allocated REF using the OCIObjectFree() function.
Comments
This function flushes the modified persistent objects from the object cache to the
server. The objects are flushed in the order that they are new or marked as updated or
marked as deleted.

See Also:
OCIObjectFlush()

This function incurs, at most, one network round-trip.

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Related Topics
•

OCIObjectFlush()
Flushes a modified persistent object to the server.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.2.2 OCICacheRefresh()
Refreshes all pinned persistent objects in the cache.
Purpose
Refreshes all pinned persistent objects in the cache.
Syntax
sword OCICacheRefresh ( OCIEnv
OCIError
const OCISvcCtx
OCIRefreshOpt
void
OCIRef
OCIRef

*env,
*err,
*svc,
option,
*context,
*(*get)(void *context),
**ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the description of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service context.
option (IN) [optional]
If OCI_REFRESH_LOADED is specified, all objects that are loaded within the transaction are
refreshed. If the option is OCI_REFRESH_LOADED and the parameter get is not NULL, this
function ignores the parameter.
context (IN) [optional]
Specifies a user context that is an argument to the client callback function get. This
parameter is set to NULL if there is no user context.

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get (IN) [optional]
A client-defined function that acts as an iterator to retrieve a batch of objects that
need to be refreshed. If the function is not NULL, this function is called to get a
reference of an object. If the reference is not NULL, then the object is refreshed. These
steps are repeated until a NULL reference is returned by this function. The parameter
context is passed to get() for each invocation of the client function. This parameter
should be NULL if user callback is not given.
ref (OUT) [optional]
If there is an error in refreshing the objects, (*ref) points to the object that is causing
the error. If ref is NULL, then the object is not returned. If *ref is NULL, then a reference
is allocated and set to point to the object. If *ref is not NULL, then the reference of the
object is copied into the given space. If the error is not caused by any of the objects,
the given ref is initialized to be a NULL reference (OCIRefIsNull(*ref) is TRUE).
Comments
This function refreshes all pinned persistent objects and frees all unpinned persistent
objects from the object cache.

Note:
When objects are refreshed, the secondary-level memory of those objects
could potentially move to a different place in memory. As a result, any
pointers to attributes that were saved prior to this call may be invalidated.
Examples of attributes using secondary-level memory include OCIString *,
OCIColl *, and OCIRaw *.

Related Topics
•

OCIObjectRefresh()
Refreshes a persistent object from the most current database snapshot.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

About Refreshing an Object Copy
When refreshed, an object copy is reloaded with the latest value of the
corresponding object in the server.

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27.2.3 OCIObjectFlush()
Flushes a modified persistent object to the server.
Purpose
Flushes a modified persistent object to the server.
Syntax
sword OCIObjectFlush ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to the persistent object. The object must be pinned before this call.
Comments
This function flushes a modified persistent object to the server. An exclusive lock is
obtained implicitly for the object when it is flushed. When this function writes the object
to the server, triggers may be fired. This function returns an error for transient objects
and values, and for unmodified persistent objects.
Objects can be modified by triggers at the server. To keep objects in the cache
consistent with the database, an application can free or refresh objects in the cache.
If the object to flush contains an internal LOB attribute and the LOB attribute was
modified due to an OCIObjectCopy(), OCILobAssign(), or OCILobLocatorAssign()
operation or by assigning another LOB locator to it, then the flush makes a copy of the
LOB value that existed in the source LOB at the time of the assignment or copy of the
internal LOB locator or object.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCICacheFlush()
Flushes modified persistent objects to the server.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectCopy()
Copies a source instance to a destination.

•

OCILobAssign()
Assigns one LOB or BFILE locator to another

•

OCILobLocatorAssign()
Assigns one LOB or BFILE locator to another.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

LOB Functions

27.2.4 OCIObjectRefresh()
Refreshes a persistent object from the most current database snapshot.
Purpose
Refreshes a persistent object from the most current database snapshot.
Syntax
sword OCIObjectRefresh ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to the persistent object, which must already be pinned.
Comments
This function refreshes an object with data retrieved from the latest snapshot in the
server. An object should be refreshed when the objects in the object cache are
inconsistent with the objects in the server.

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Note:
When an object is flushed to the server, triggers can be fired to modify more
objects in the server. The same objects (modified by the triggers) in the
object cache become out-of-date, and must be refreshed before they can be
locked or flushed.
This occurs when the user issues a SQL statement or PL/SQL procedure to
modify any object in the server.

Note:
Modifications made to objects (dirty objects) since the last flush are lost if
unmarked objects are refreshed by this function.

Table 27-5 shows how the various meta-attribute flags and durations of an object are
modified after being refreshed.
Table 27-5

Object Status After Refresh

Object Attribute

Status After Refresh

existent

Set to appropriate value

pinned

Unchanged

allocation duration

Unchanged

pin duration

Unchanged

The object that is refreshed is replaced-in-place. When an object is replaced-in-place,
the top-level memory of the object is reused so that new data can be loaded into the
same memory address. The top-level memory of the NULL indicator structure is also
reused. Unlike the top-level memory chunk, the secondary memory chunks are freed
and reallocated.
You should be careful when writing functionality that retains a pointer to the secondary
memory chunk, such as assigning the address of a secondary memory chunk to a
local variable, because this pointer can become invalid after the object is refreshed.
This function does no affect transient objects or values.
Related Topics
•

OCICacheRefresh()
Refreshes all pinned persistent objects in the cache.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.3 OCI Mark or Unmark Object and Cache Functions
Lists and describes the OCI mark or unmark object and cache functions.
Table 27-6 describes the OCI mark or unmark object and cache functions that are
described in this section.
Table 27-6

Mark or Unmark Object and Cache Functions

Function

Purpose

OCICacheUnmark()

Unmark objects in the cache

OCIObjectMarkDelete()

Mark an object deleted or delete a
value instance

OCIObjectMarkDeleteByRef()

Mark an object deleted when given a
reference to it

OCIObjectMarkUpdate()

Mark an object as updated or dirty

OCIObjectUnmark()

Unmark an object

OCIObjectUnmarkByRef()

Unmark an object, when given a
reference to it

27.3.1 OCICacheUnmark()
Unmarks all dirty objects in the object cache.
Purpose
Unmarks all dirty objects in the object cache.
Syntax
sword OCICacheUnmark ( OCIEnv
OCIError
const OCISvcCtx

*env,
*err,
*svc );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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svc (IN)
OCI service context.
Comments
If a connection is specified, this function unmarks all dirty objects in that connection.
Otherwise, all dirty objects in the cache are unmarked.
Related Topics
•

OCIObjectUnmark()
Unmarks an object as dirty.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
OCIObjectUnmark() for more information about unmarking an object

27.3.2 OCIObjectMarkDelete()
Marks a standalone instance as deleted, when given a pointer to the instance.
Purpose
Marks a standalone instance as deleted, when given a pointer to the instance.
Syntax
sword OCIObjectMarkDelete ( OCIEnv
OCIError
void

*env,
*err,
*instance );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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instance (IN)
Pointer to the instance. It must be standalone, and if it is an object, it must be pinned.
Comments
This function accepts a pointer to a standalone instance and marks the object as
deleted. The object is freed according to the following rules:
For Persistent Objects
The object is marked deleted. The memory of the object is not freed. The object is
deleted in the server when the object is flushed.
For Transient Objects
The object is marked deleted. The memory of the object is not freed.
For Values
This function frees a value immediately.
Related Topics
•

OCIObjectMarkDeleteByRef()
Marks an object as deleted, when given a reference to the object.

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.3.3 OCIObjectMarkDeleteByRef()
Marks an object as deleted, when given a reference to the object.
Purpose
Marks an object as deleted, when given a reference to the object.
Syntax
sword OCIObjectMarkDeleteByRef ( OCIEnv
OCIError
OCIRef

*env,
*err,
*object_ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object_ref (IN)
Reference to the object to be deleted.
Comments
This function accepts a reference to an object, and marks the object designated by
object_ref as deleted. The object is marked and freed as follows:
For Persistent Objects
If the object is not loaded, then a temporary object is created and is marked deleted.
Otherwise, the object is marked deleted.
The object is deleted in the server when the object is flushed.
For Transient Objects
The object is marked deleted. The object is not freed until it is unpinned.
Related Topics
•

OCIObjectMarkDelete()
Marks a standalone instance as deleted, when given a pointer to the instance.

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.3.4 OCIObjectMarkUpdate()
Marks a persistent object as updated (dirty).
Purpose
Marks a persistent object as updated (dirty).
Syntax
sword OCIObjectMarkUpdate ( OCIEnv
OCIError
void

*env,
*err,
*object );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to the persistent object, which must already be pinned.
Comments
This function marks a persistent object as updated (dirty). The following special rules
apply to different types of objects. The dirty status of an object can be checked by
calling OCIObjectIsLocked().
For Persistent Objects
This function marks the specified persistent object as updated.
When the object cache is flushed, it writes the persistent objects to the server. The
object is not locked or flushed by this function. It is an error to update a deleted object.
After an object is marked updated and flushed, this function must be called again to
mark the object as updated if it has been dirtied after being flushed.
For Transient Objects
This function marks the specified transient object as updated. The transient objects
are not written to the server. It is an error to update a deleted object.
For Values
This function has no effect on values.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIObjectIsDirty()
Checks to see if an object is marked as dirty.

•

OCIObjectUnmark()
Unmarks an object as dirty.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

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•

OCIObjectIsLocked()
Gets lock status of an object.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

About Marking Objects and Flushing Changes
The application must take specific steps to ensure that changes to objects by
marking them and then flushing them are written in the database.

27.3.5 OCIObjectUnmark()
Unmarks an object as dirty.
Purpose
Unmarks an object as dirty.
Syntax
sword OCIObjectUnmark ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
Pointer to the persistent object. It must be pinned.
Comments
For Persistent Objects and Transient Objects
This function unmarks the specified persistent object as dirty. Changes that are made
to the object are not written to the server. If the object is marked as locked, it remains
marked as locked. The changes that have already been made to the object are not
undone implicitly.
For Values
This function has no effect if called on a value.
Related Topics
•

OCIObjectUnmarkByRef()
Unmarks an object as dirty, when given a ref to the object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.3.6 OCIObjectUnmarkByRef()
Unmarks an object as dirty, when given a ref to the object.
Purpose
Unmarks an object as dirty, when given a ref to the object.
Syntax
sword OCIObjectUnmarkByRef ( OCIEnv
OCIError
OCIRef

*env,
*err,
*ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
ref (IN)
Reference of the object. It must be pinned.
Comments
This function unmarks an object as dirty. This function is identical to OCIObjectUnmark(),
except that it takes a ref to the object as an argument.
For Persistent Objects and Transient Objects
This function unmarks the specified persistent object as dirty. Changes that are made
to the object are not written to the server. If the object is marked as locked, it remains
marked as locked. The changes that have already been made to the object are not
undone implicitly.
For Values
This function has no effect on values.
Related Topics
•

OCIObjectUnmark()
Unmarks an object as dirty.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.4 OCI Get Object Status Functions
Lists and describes the OCI get object status functions.
Table 27-7 describes the OCI get object status functions that are described in this
section.
Table 27-7

Get Object Status Functions

Function

Purpose

OCIObjectExists()

Get the existent status of an instance

OCIObjectGetProperty()

Get the status of a particular object
property

OCIObjectIsDirty()

Get the dirtied status of an instance

OCIObjectIsLocked()

Get the locked status of an instance

27.4.1 OCIObjectExists()
Returns the existence meta-attribute of a standalone instance.
Purpose
Returns the existence meta-attribute of a standalone instance.
Syntax
sword OCIObjectExists ( OCIEnv
OCIError
void
boolean

*env,
*err,
*ins,
*exist );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
ins (IN)
Pointer to an instance. If it is an object, it must be pinned.

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exist (OUT)
Return value for the existence status.
Comments
This function returns the existence meta-attribute of an instance. If the instance is a
value, this function always returns TRUE. The instance must be a standalone persistent
or transient object.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Object Meta-Attributes
An object's meta-attributes serve as flags that can provide information to an
application, or to the object cache, about the status of an object.

27.4.2 OCIObjectGetProperty()
Retrieves a given property of an object.
Purpose
Retrieves a given property of an object.
Syntax
sword OCIObjectGetProperty ( OCIEnv
OCIError
const void
OCIObjectPropId
void
ub4

*envh,
*errh,
*obj,
propertyId,
*property,
*size );

Parameters
envh (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
errh (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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obj (IN)
The object whose property is returned.
propertyId (IN)
The identifier that specifies the property.
property (OUT)
The buffer into which the specified property is copied.
size (IN/OUT)
On input, this parameter specifies the size of the property buffer passed by the caller.
On output, it contains the size in bytes of the property returned. This parameter is
required for string-type properties only, such as OCI_OBJECTPROP_SCHEMA and
OCI_OBJECTPROP_TABLE. For non-string properties this parameter is ignored because the
size is fixed.
Comments
This function returns the specified property of the object. This property is identified by
propertyId. The property value is copied into property and for string typed properties,
the string size is returned by size.

Objects are classified as persistent, transient, and value depending upon the lifetime
and referenceability of the object. Some of the properties are applicable only to
persistent objects and some others apply only to persistent and transient objects. An
error is returned if the user tries to get a property that is not applicable to the given
object. To avoid such an error, first check whether the object is persistent or transient
or value (OCI_OBJECTPROP_LIFETIME property) and then appropriately query for other
properties.
The different property IDs and the corresponding type of property argument are given
next.
OCI_OBJECTPROP_LIFETIME
This identifies whether the given object is a persistent object or a transient object or a
value instance. The property argument must be a pointer to a variable of type
OCIObjectLifetime. Possible values include:
•

OCI_OBJECT_PERSISTENT

•

OCI_OBJECT_TRANSIENT

•

OCI_OBJECT_VALUE

OCI_OBJECTPROP_SCHEMA
This returns the schema name of the table in which the object exists. An error is
returned if the given object points to a transient instance or a value. If the input buffer
is not big enough to hold the schema name, an error is returned; the error message
communicates the required size. Upon success, the size of the returned schema
name in bytes is returned by size. The property argument must be an array of type
text, and size should be set to size of array in bytes by the caller.
OCI_OBJECTPROP_TABLE
This returns the table name in which the object exists. An error is returned if the given
object points to a transient instance or a value. If the input buffer is not big enough to
hold the table name, an error is returned; the error message communicates the
required size. Upon success, the size of the returned table name in bytes is returned

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by size. The property argument must be an array of type text, and size should be set
to size of array in bytes by the caller.
OCI_OBJECTPROP_PIN_DURATION
This returns the pin duration of the object. An error is returned if the given object
points to a value instance. The property argument must be a pointer to a variable of
type OCIDuration. Valid values include:
•

OCI_DURATION_SESSION

•

OCI_DURATION_TRANS

For more information about durations, see Object Duration.
OCI_OBJECTPROP_ALLOC_DURATION
This returns the allocation duration of the object. The property argument must be a
pointer to a variable of type OCIDuration. Valid values include:
•

OCI_DURATION_SESSION

•

OCI_DURATION_TRANS

For more information about durations, see Object Duration.
OCI_OBJECTPROP_LOCK
This returns the lock status of the object. The possible lock statuses are enumerated
by OCILockOpt. An error is returned if the given object points to a transient or value
instance. The property argument must be a pointer to a variable of type OCILockOpt.
The lock status of an object can also be retrieved by calling OCIObjectIsLocked(). Valid
values include:
•

OCI_LOCK_NONE (no lock)

•

OCI_LOCK_X (exclusive lock)

•

OCI_LOCK_X_NOWAIT (exclusive lock with the NOWAIT option)

See Also:
About Locking with the NOWAIT Option
OCI_OBJECTPROP_MARKSTATUS
This returns the dirty status and indicates whether the object is a new object, updated
object, or deleted object. An error is returned if the given object points to a transient or
value instance. The property argument must be of type OCIObjectMarkStatus. Valid
values include:
•

OCI_OBJECT_NEW

•

OCI_OBJECT_DELETED

•

OCI_OBJECT_UPDATED

The following macros are available to test the object mark status:
•

OCI_OBJECT_IS_UPDATED (flag)

•

OCI_OBJECT_IS_DELETED (flag)

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•

OCI_OBJECT_IS_NEW (flag)

•

OCI_OBJECT_IS_DIRTY (flag)

OCI_OBJECTPROP_VIEW
This identifies whether the specified object is a view object or not. If the property value
returned is TRUE, the object is a view; otherwise, it is not. An error is returned if the
given object points to a transient or value instance. The property argument must be of
type boolean.
Related Topics
•

OCIObjectLock()
Locks a persistent object at the server.

•

OCIObjectMarkDelete()
Marks a standalone instance as deleted, when given a pointer to the instance.

•

OCIObjectMarkUpdate()
Marks a persistent object as updated (dirty).

•

OCIObjectPin()
Pins a referenceable object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectIsLocked()
Gets lock status of an object.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.4.3 OCIObjectIsDirty()
Checks to see if an object is marked as dirty.
Purpose
Checks to see if an object is marked as dirty.
Syntax
sword OCIObjectIsDirty ( OCIEnv
OCIError
void
boolean

*env,
*err,
*ins,
*dirty );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
ins (IN)
Pointer to an instance.
dirty (OUT)
Return value for the dirty status.
Comments
The instance passed to this function must be standalone. If the instance is an object,
the instance must be pinned.
This function returns the dirty status of an instance. If the instance is a value, this
function always returns FALSE for the dirty status.
Related Topics
•

OCIObjectMarkUpdate()
Marks a persistent object as updated (dirty).

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.4.4 OCIObjectIsLocked()
Gets lock status of an object.
Purpose
Gets lock status of an object.
Syntax
sword OCIObjectIsLocked ( OCIEnv
OCIError

*env,
*err,

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void
boolean

*ins,
*lock );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
ins (IN)
Pointer to an instance. The instance must be standalone, and if it is an object, it must
be pinned.
lock (OUT)
Return value for the lock status.
Comments
This function returns the lock status of an instance. If the instance is a value, this
function always returns FALSE.
Related Topics
•

OCIObjectLock()
Locks a persistent object at the server.

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.5 OCI Miscellaneous Object Functions
Lists and describes the miscellaneous object functions.
Table 27-8 describes the miscellaneous object functions that are described in this
section.
Table 27-8

Miscellaneous Object Functions

Function

Purpose

OCIObjectCopy()

Copy one instance to another

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Table 27-8

(Cont.) Miscellaneous Object Functions

Function

Purpose

OCIObjectGetAttr()

Get an object attribute

OCIObjectGetInd()

Get NULL structure of an instance

OCIObjectGetObjectRef()

Return reference to a given object

OCIObjectGetTypeRef()

Get a reference to a TDO of an
instance

OCIObjectLock()

Lock a persistent object

OCIObjectLockNoWait()

Lock a persistent object but do not wait
for the lock

OCIObjectNew()

Create a new instance

OCIObjectSetAttr()

Set an object attribute

27.5.1 OCIObjectCopy()
Copies a source instance to a destination.
Purpose
Copies a source instance to a destination.
Syntax
sword OCIObjectCopy ( OCIEnv
OCIError
const OCISvcCtx
void
void
void
void
OCIType
OCIDuration
ub1

*env,
*err,
*svc,
*source,
*null_source,
*target,
*null_target,
*tdo,
duration,
option );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
An OCI service context handle, specifying the service context on which the copy
operation is occurring.
source (IN)
A pointer to the source instance; if it is an object, it must be pinned.

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See Also:
OCIObjectPin()

null_source (IN)
Pointer to the NULL structure of the source object.
target (IN)
A pointer to the target instance; if it is an object, it must be pinned.
null_target (IN)
A pointer to the NULL structure of the target object.
tdo (IN)
The TDO for both the source and the target. Can be retrieved with OCIDescribeAny().
duration (IN)
Allocation duration of the target memory.
option (IN)
This parameter is currently unused. Pass as zero or OCI_DEFAULT.
Comments
This function copies the contents of the source instance to the target instance. This
function performs a deep copy such that all of the following information is copied:
•

All the top-level attributes (see the exceptions later)

•

All secondary memory (of the source) reachable from the top-level attributes

•

The NULL structure of the instance

Memory is allocated with the duration specified in the duration parameter.
Certain data items are not copied, such as, if the attribute is an internal LOB, then only
the LOB locator from the source object is copied. A copy of the LOB data is not made
until OCIObjectFlush() is called. Before the target object is flushed, both the source and
the target locators refer to the same LOB value.
The target or the containing instance of the target must have been created. This can
be done with OCIObjectNew() or OCIObjectPin() depending on whether the target object
exists.
The source and target instances must be of the same type. If the source and target are
located in different databases, then the same type must exist in both databases.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectFlush()
Flushes a modified persistent object to the server.

•

OCIObjectNew()
Creates a standalone instance.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.5.2 OCIObjectGetAttr()
Retrieves an object attribute.
Purpose
Retrieves an object attribute.
Syntax
sword OCIObjectGetAttr ( OCIEnv
OCIError
void
void
struct OCIType
const OraText
const ub4
const ub4
const ub4
const ub4
OCIInd
void
void
struct OCIType

*env,
*err,
*instance,
*null_struct,
*tdo,
**names,
*lengths,
name_count,
*indexes,
index_count,
*attr_null_status,
**attr_null_struct,
**attr_value,
**attr_tdo );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
instance (IN)
Pointer to an object.
null_struct (IN)
The NULL structure of the object or array.
tdo (IN)
Pointer to the type descriptor object (TDO).

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names (IN)
Array of attribute names. This is used to specify the names of the attributes in the
path expression.
lengths (IN)
Array of lengths of attribute names, in bytes.
name_count (IN)
Number of elements in the array names.
indexes (IN) [optional]
Not currently supported. Pass as (ub4 *)0.
index_count (IN) [optional]
Not currently supported. Pass as (ub4)0.
attr_null_status (OUT)
The NULL status of the attribute if the type of attribute is primitive.
attr_null_struct (OUT)
This parameter is filled only for object and opaque attributes, not for collections. For
collections (pass OCICollGetElem), attr_null_struct is NULL. For collections, this
parameter indicates if the entire collection is NULL or not.
attr_value (OUT)
Pointer to the attribute value. See
Table 24-1 that lists the type of data and what C data type can be found in parameter
attr_value after this call completes successfully.
attr_tdo (OUT)
Pointer to the TDO of the attribute.
Comments
This function gets a value from an object. The position of the attribute returned is
specified as a path expression, which is an array of names and an array of indexes. If
the parameter instance points to an object, then the path expression specifies the
location of the attribute in the object. It is assumed that the object is pinned and that
the value returned is valid until the object is unpinned. The values returned are
considered read-only and should not be modified in any way.
If both attr_null_status and attr_null_struct are NULL, no NULL information is returned.
Example
For the path expression stanford.cs.stu[5].addr, the arrays appear as:
names = {"stanford", "cs", "stu", "addr"}
lengths = {8, 2, 3, 4}
indexes = {5}
Related Topics
•

OCIObjectSetAttr()
Sets an object attribute.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.5.3 OCIObjectGetInd()
Retrieves the NULL indicator structure of a standalone instance.
Purpose
Retrieves the NULL indicator structure of a standalone instance.
Syntax
sword OCIObjectGetInd ( OCIEnv
OCIError
void
void

*env,
*err,
*instance,
**null_struct );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
instance (IN)
A pointer to the instance whose NULL structure is being retrieved. The instance must
be standalone. If instance is an object, it must already be pinned.
null_struct (OUT)
The NULL indicator structure for the instance.

See Also:
NULL Indicator Structure for a discussion of the NULL indicator structure and
examples of its use

Comments
None.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

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•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.5.4 OCIObjectGetObjectRef()
Returns a reference to a given persistent object.
Purpose
Returns a reference to a given persistent object.
Syntax
sword OCIObjectGetObjectRef ( OCIEnv
OCIError
void
OCIRef

*env,
*err,
*object,
*object_ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
Pointer to a persistent object. It must already be pinned.
object_ref (OUT)
A reference to the object specified in object. The reference must already be allocated.
This can be accomplished with OCIObjectNew().
Comments
This function returns a reference to the given persistent object, when given a pointer to
the object. Passing a value (rather than an object) to this function causes an error.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Object Meta-Attributes
An object's meta-attributes serve as flags that can provide information to an
application, or to the object cache, about the status of an object.

27.5.5 OCIObjectGetTypeRef()
Returns a reference to the type descriptor object (TDO) of a standalone instance.
Purpose
Returns a reference to the type descriptor object (TDO) of a standalone instance.
Syntax
sword OCIObjectGetTypeRef ( OCIEnv
OCIError
void
OCIRef

*env,
*err,
*instance,
*type_ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
instance (IN)
A pointer to the standalone instance. It must be standalone, and if it is an object, it
must already be pinned.
type_ref (OUT)
A reference to the type of the object. The reference must already be allocated. This
can be accomplished with OCIObjectNew().
Comments
None.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectNew()
Creates a standalone instance.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.5.6 OCIObjectLock()
Locks a persistent object at the server.
Purpose
Locks a persistent object at the server.
Syntax
sword OCIObjectLock ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to the persistent object being locked. It must already be pinned.
Comments
This function returns an error for transient objects and values. It also returns an error if
the object does not exist.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIObjectIsLocked()
Gets lock status of an object.

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIObjectLockNoWait()
Locks a persistent object at the server but does not wait for the lock.

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•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

About Locking Objects for Update
The program can optionally call OCIObjectLock() to lock an object for update.

27.5.7 OCIObjectLockNoWait()
Locks a persistent object at the server but does not wait for the lock.
Purpose
Locks a persistent object at the server but does not wait for the lock. Returns an error
if the lock is unavailable.
Syntax
sword OCIObjectLockNoWait ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to the persistent object being locked. It must already be pinned.
Comments
This function locks a persistent object at the server. However, unlike OCIObjectLock(),
this function does not wait if another user holds the lock on the object and an error is
returned if the object is currently locked by another user. This function also returns an
error for transient objects and values, or objects that do not exist.
The lock of an object is released at the end of a transaction.
OCIObjectLockNoWait() returns the following values:

•

OCI_INVALID_HANDLE, if the environment handle or error handle is NULL

•

OCI_SUCCESS, if the operation succeeds

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•

OCI_ERROR, if the operation fails

Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIObjectIsLocked()
Gets lock status of an object.

•

OCIObjectGetProperty()
Retrieves a given property of an object.

•

OCIObjectLock()
Locks a persistent object at the server.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

About Locking Objects for Update
The program can optionally call OCIObjectLock() to lock an object for update.

27.5.8 OCIObjectNew()
Creates a standalone instance.
Purpose
Creates a standalone instance.
Syntax
sword OCIObjectNew ( OCIEnv
*env,
OCIError
*err,
const OCISvcCtx *svc,
OCITypeCode
typecode,
OCIType
*tdo,
void
*table,
OCIDuration
duration,
boolean
value,
void
**instance );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. The handle can be initialized
in UTF-16 (Unicode) mode. See the description of OCIEnvNlsCreate().

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service handle.
typecode (IN)
The typecode of the type of the instance.

See Also:
Typecodes
tdo (IN) [optional]
Pointer to the type descriptor object. The TDO describes the type of the instance that
is to be created. See OCITypeByName() for obtaining a TDO. The TDO is required for
creating a named type, such as an object or a collection.
table (IN) [optional]
Pointer to a table object that specifies a table in the server. This parameter can be set
to NULL if no table is given. See the following description to learn how the table object
and the TDO are used together to determine the kind of instances (persistent,
transient, value) to be created. Also see OCIObjectPinTable() for retrieving a table
object.
duration (IN)
This is an overloaded parameter. The use of this parameter is based on the kind of
the instance that is to be created. See Table 27-9 for more information.
•

For a persistent object type of instance, this parameter specifies the pin duration.

•

For a transient object type of instance, this parameter specifies the allocation
duration and pin duration.

•

For a value type of instance, this parameter specifies the allocation duration.

value (IN)
Specifies whether the created object is a value. If TRUE, then a value is created.
Otherwise, a referenceable object is created. If the instance is not an object, then this
parameter is ignored.
instance (OUT)
Address of the newly created instance. The instance can be a character string in
UTF-16 (Unicode) if the environment handle has the appropriate setting and the
object is OCIString.
Comments
This function creates a new instance of the type specified by the typecode or the TDO.
The type can be complex or primitive.
For Records
When creating a package record type using OCIObjectNew(), clients must use
typecode OCI_TYPECODE_RECORD when instantiating a record type.

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Records are allocated in the allocation duration specified in OCIObjectNew(). They are
subsequently freed at the end of that duration.
Record field initializers are not supported for records instantiated on the client. For
instance, given the following mypack package definition, the following error is returned
when you resolve it using OCITypeByFullName(): OCI-22352: Type is unsupported or
contains an unsupported attribute or element. (Thus, you will never even get to call
OCIObjectNew()).
create or replace package mypack is
type r is record (rec_field number := 10);
end;

All records are null activated; that is, all fields of an instantiated record are set to NULL.
In keeping with PL/SQL null semantics, all instantiated records are also atomically
not-NULL.
For Collections
When creating a new instance of a package collection type, the value parameter must
be TRUE. This is because package collection types cannot be persistent or
referenceable, and so they must always be instantiated as values. Calling
OCIObjectNew() for a package collection type with a FALSE value parameter results in
an error.
Package collections are allocated in the allocation duration specified in
OCIObjectNew(). They are subsequently freed at the end of that duration.
When creating a package, clients can use the typecodes as follows:
•

OCI_TYPECODE_NAMEDCOLLECTION for schema level collections and package collection

types
•

OCI_TYPECODE_ITABLE for index tables

•

OCI_TYPECODE_TABLE for nested tables

•

OCI_TYPECODE_VARRAY for varrays

For Booleans
When creating new Boolean types, clients should use OCI_TYPECODE_BOOLEAN.
OCI String Objects
It can create an OCIString object with a Unicode buffer if the typecode indicates the
object to be created is OCIString.

See Also:
Typecodes
Table 27-9 shows that based on the parameters typecode (or tdo), value, and table,
different instances are created.
Type of the Instance

Table != NULL

Table == NULL

object type (value=TRUE)

value

value

object type (value=FALSE)

persistent object

transient object

built-in type

value

value

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Type of the Instance

Table != NULL

Table == NULL

collection type

value

value

This function allocates the top-level memory chunk of an instance. The attributes in
the top-level memory are initialized, which means that an attribute of VARCHAR2 is
initialized to an OCIString of 0 length. If the instance is an object, the object is marked
existent but is atomically NULL.

See Also:
Create Objects Based on Object Views and Object Tables with PrimaryKey-Based OIDs for information about creating new objects based on object
views or user-created OIDs
For Persistent Objects
The object is marked dirty and existent. The allocation duration for the object is
session. The object is pinned, and the pin duration is specified by the given parameter
duration. Creating a persistent object does not cause any entries to be made into a
database table until the object is flushed to the server.
For Transient Objects
The object is pinned. The allocation duration and the pin duration are specified by the
given parameter duration.
For Values
The allocation duration is specified by the given parameter duration.
Attribute Values of New Objects
By default, all attributes of a newly created object have NULL values. After initializing
attribute data, the user must change the corresponding NULL status of each attribute to
non-NULL.
It is possible to have attributes set to non-NULL values when an object is created. This
is accomplished by setting the OCI_ATTR_OBJECT_NEWNOTNULL attribute of the environment
handle to TRUE using OCIAttrSet(). This mode can later be turned off by setting the
attribute to FALSE. If OCI_ATTR_OBJECT_NEWNOTNULL is set to TRUE, then OCIObjectNew()
creates a non-NULL object.

See Also:
Attribute Values of New Objects

Objects with LOB Attributes
If the object contains an internal LOB attribute, the LOB is set to empty. The object
must be marked as dirty and flushed (to insert the object into the table) and repinned
before the user can start writing data into the LOB. When pinning the object after
creating it, you must use the OCI_PIN_LATEST pin option to retrieve the newly updated
LOB locator from the server.

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If the object contains an external LOB attribute (FILE), the FILE locator is allocated but
not initialized. The user must call OCILobFileSetName() to initialize the FILE attribute
before flushing the object to the database. It is an error to perform an INSERT or UPDATE
operation on a FILE without first indicating a directory object and file name. Once the
file name is set, the user can start reading from the FILE.

Note:
Oracle Database supports only binary FILEs (BFILEs).

Related Topics
•

OCIObjectPinTable()
Pins a table object for a specified duration.

•

OCIObjectFree()
Frees and unpins an object instance.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCILobFileSetName()
Sets the directory object and file name in the BFILE locator.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.5.9 OCIObjectSetAttr()
Sets an object attribute.
Purpose
Sets an object attribute.
Syntax
sword OCIObjectSetAttr ( OCIEnv
OCIError
void
void
struct OCIType
const OraText
const ub4
const ub4
const ub4
const ub4
const OCIInd
const void
const void

*env,
*err,
*instance,
*null_struct,
*tdo,
**names,
*lengths,
name_count,
*indexes,
index_count,
attr_null_status,
*attr_null_struct,
*attr_value );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
instance (IN)
Pointer to an object instance.
null_struct (IN)
The NULL structure of the object instance or array.
tdo (IN)
Pointer to the TDO.
names (IN)
Array of attribute names. This is used to specify the names of the attributes in the
path expression.
lengths (IN)
Array of lengths of attribute names, in bytes.
name_count (IN)
Number of elements in the array names.
indexes (IN) [optional]
Not currently supported. Pass as (ub4 *)0.
index_count (IN) [optional]
Not currently supported. Pass as (ub4)0.
attr_null_status (IN)
The NULL status of the attribute if the type of attribute is primitive.
attr_null_struct (IN)
The NULL structure of an object or collection attribute.
attr_value (IN)
Pointer to the attribute value. See Table 24-1 that lists the type of data and what C
data type can be found in parameter attr_value after this call completes successfully.
Note that the given element is deep copied, and attr_value is strictly an input
parameter.
Comments
This function sets the attribute of the given object with the given value. The position of
the attribute is specified as a path expression, which is an array of names and an array
of indexes.
Example
For the path expression stanford.cs.stu[5].addr, the arrays appear as:

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names = {"stanford", "cs", "stu", "addr"}
lengths = {8, 2, 3, 4}
indexes = {5}
Related Topics
•

OCIObjectGetAttr()
Retrieves an object attribute.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.6 OCI Pin, Unpin, and Free Functions
Lists and describes the OCI pin, unpin, and free functions.
Table 27-10 describes the OCI pin, unpin, and free functions that are described in this
section.
Table 27-10

Pin, Unpin, and Free Functions

Function

Purpose

OCICacheFree()

Free objects in the cache

OCICacheUnpin()

Unpin persistent objects in cache or connection

OCIObjectArrayPin()

Pin an array of references

OCIObjectFree()

Free a previously allocated object

OCIObjectPin()

Pin an object

OCIObjectPinCountReset()

Unpin an object to zero pin count

OCIObjectPinTable()

Pin a table object with a given duration

OCIObjectUnpin()

Unpin an object

27.6.1 OCICacheFree()
Frees all objects and values in the cache for the specified connection.
Purpose
Frees all objects and values in the cache for the specified connection.

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Syntax
sword OCICacheFree ( OCIEnv
OCIError
const OCISvcCtx

*env,
*err,
*svc );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
An OCI service context.
Comments
If a connection is specified, this function frees the persistent objects, transient objects
and values allocated for that connection. Otherwise, all persistent objects, transient
objects and values in the object cache are freed. Objects are freed regardless of their
pin count.
Related Topics
•

OCIObjectFree()
Frees and unpins an object instance.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
OCIObjectFree() for more information about freeing an instance

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27.6.2 OCICacheUnpin()
Unpins persistent objects.
Purpose
Unpins persistent objects.
Syntax
sword OCICacheUnpin ( OCIEnv
OCIError
const OCISvcCtx

*env,
*err,
*svc );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
An OCI service context handle. The objects on the specified connection are unpinned.
Comments
This function completely unpins all of the persistent objects for the given connection.
The pin count for the objects is reset to zero.
Related Topics
•

OCIObjectUnpin()
Unpins an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Pinning an Object
Pinning an object loads the object instance into the object cache, and enables you
to access and modify the instance's attributes and follow references from that
object to other objects, if necessary.

•

Pin Count and Unpinning
Each object in the object cache has a pin count associated with it.

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27.6.3 OCIObjectArrayPin()
Pins an array of references.
Purpose
Pins an array of references.
Syntax
sword OCIObjectArrayPin ( OCIEnv
OCIError
OCIRef
ub4
OCIComplexObject
ub4
OCIPinOpt
OCIDuration
OCILockOpt
void
ub4

*env,
*err,
**ref_array,
array_size,
**cor_array,
cor_array_size,
pin_option,
pin_duration,
lock,
**obj_array,
*pos );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
ref_array (IN)
Array of references to be pinned.
array_size (IN)
Number of elements in the array of references.
cor_array
An array of COR handles corresponding to the objects being pinned.
cor_array_size
The number of elements in cor_array.
pin_option (IN)
Pin option.

See Also:
OCIObjectPin()

pin_duration (IN)
Pin duration. See OCIObjectPin().

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lock (IN)
Lock option. See OCIObjectPin().
obj_array (OUT)
If this argument is not NULL, the pinned objects are returned in the array. The user
must allocate this array with the element type being void *. The size of this array is
identical to array_size.
pos (OUT)
If there is an error, this argument indicates the element that is causing the error. Note
that this argument is set to 1 for the first element in the ref_array.
Comments
All the pinned objects are retrieved from the database in one network round-trip. If the
user specifies an output array (obj_array), then the address of the pinned objects are
assigned to the elements in the array.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.6.4 OCIObjectFree()
Frees and unpins an object instance.
Purpose
Frees and unpins an object instance.
Syntax
sword OCIObjectFree ( OCIEnv
OCIError
void
ub2

*env,
*err,
*instance,
flags );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
instance (IN)
Pointer to a standalone instance. If it is an object, it must be pinned.
flags (IN)
If OCI_OBJECTFREE_FORCE is passed, free the object even if it is pinned or dirty. If
OCI_OBJECTFREE_NONULL is passed, the NULL structure is not freed.
Comments
This function deallocates all the memory allocated for an object instance, including the
NULL structure. The following rules apply to different instance types:
For Persistent Objects
This function returns an error if the client is attempting to free a dirty persistent object
that has not been flushed. The client should either flush the persistent object, unmark
it, or set the parameter flags to OCI_OBJECTFREE_FORCE.
This function calls OCIObjectUnpin() once to check if the object can be completely
unpinned. If it succeeds, the rest of the function proceeds to free the object. If it fails,
then an error is returned unless the parameter flags is set to OCI_OBJECTFREE_FORCE.
Freeing a persistent object in memory does not change the persistent state of that
object at the server. For example, the object remains locked after the object is freed.
For Transient Objects
This function calls OCIObjectUnpin() once to check if the object can be completely
unpinned. If it succeeds, the rest of the function proceeds to free the object. If it fails,
then an error is returned unless the parameter flags is set to OCI_OBJECTFREE_FORCE.
For Values
The memory of the object is freed immediately.
Related Topics
•

OCICacheFree()
Frees all objects and values in the cache for the specified connection.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.6.5 OCIObjectPin()
Pins a referenceable object.
Purpose
Pins a referenceable object.

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Syntax
sword OCIObjectPin ( OCIEnv
OCIError
OCIRef
OCIComplexObject
OCIPinOpt
OCIDuration
OCILockOpt
void

*env,
*err,
*object_ref,
*corhdl,
pin_option,
pin_duration,
lock_option,
**object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object_ref (IN)
The reference to the object.
corhdl (IN)
Handle for complex object retrieval.
pin_option (IN)
Used to specify the copy of the object that is to be retrieved.
pin_duration (IN)
The duration during which the object is being accessed by a client. The object is
implicitly unpinned at the end of the pin duration. If OCI_DURATION_NULL is passed, there
is no pin promotion if the object is already loaded into the cache. If the object is not
yet loaded, then the pin duration is set to OCI_DURATION_DEFAULT for OCI_DURATION_NULL.
lock_option (IN)
Lock option (for example, exclusive). If a lock option is specified, the object is locked
in the server. The lock status of an object can also be retrieved by calling
OCIObjectIsLocked(). Valid values include:
•

OCI_LOCK_NONE (no lock)

•

OCI_LOCK_X (exclusive lock)

•

OCI_LOCK_X_NOWAIT (exclusive lock with the NOWAIT option)

See Also:
About Locking with the NOWAIT Option
object (OUT)
The pointer to the pinned object.

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Comments
This function pins a referenceable object instance when given the object reference.
The process of pinning serves two purposes:
•

It locates an object given its reference. This is done by the object cache that keeps
track of the objects in the object cache.

•

It notifies the object cache that a persistent object is being used such that the
persistent object cannot be aged out. Because a persistent object can be loaded
from the server whenever is needed, the memory utilization can be increased if a
completely unpinned persistent object can be freed (aged out) even before the
allocation duration is expired. An object can be pinned many times. A pinned
object remains in memory until it is completely unpinned.

See Also:
OCIObjectUnpin()

For Persistent Objects
When pinning a persistent object, if it is not in the cache, the object is fetched from the
persistent store. The allocation duration of the object is session. If the object is
already in the cache, it is returned to the client. The object is locked in the server if a
lock option is specified.
This function returns an error for a nonexistent object.
A pin option is used to specify the copy of the object that is to be retrieved:
•

If pin_option is OCI_PIN_ANY (pin any), then if the object is already in the object
cache, return this object. Otherwise, the object is retrieved from the database. In
this case, it is the same as OCI_PIN_LATEST. This option is useful when the client
knows that he has the exclusive access to the data in a session.

•

If pin_option is OCI_PIN_LATEST (pin latest), if the object is not locked, it is retrieved
from the database. If the object is cached, it is refreshed with the latest version.
See OCIObjectRefresh() for more information about refreshing. If the object is
already pinned in the cache and marked dirty, then a pointer to that object is
returned. The object is not refreshed from the database.

•

If pin_option is OCI_PIN_RECENT (pin recent), if the object is loaded into the cache in
the current transaction, the object is returned. If the object is not loaded in the
current transaction, the object is refreshed from the server.

For Transient Objects
This function returns an error if the transient object has already been freed. This
function does not return an error if an exclusive lock is specified in the lock option.
Related Topics
•

OCIObjectUnpin()
Unpins an object.

•

OCIObjectPinCountReset()
Completely unpins an object, setting its pin count to zero.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.6.6 OCIObjectPinCountReset()
Completely unpins an object, setting its pin count to zero.
Purpose
Completely unpins an object, setting its pin count to zero.
Syntax
sword OCIObjectPinCountReset ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to an object, which must already be pinned.
Comments
This function completely unpins an object, setting its pin count to zero. When an object
is completely unpinned, it can be freed implicitly by the OCI at any time without error.
The following rules apply to specific object types:
For Persistent Objects
When a persistent object is completely unpinned, it becomes a candidate for aging.
The memory of an object is freed when it is aged out. Aging is used to maximize the
utilization of memory. A dirty object cannot be aged out unless it is flushed.
For Transient Objects
The pin count of the object is decremented. A transient object can be freed only at the
end of its allocation duration or when it is explicitly freed by calling OCIObjectFree().
For Values
This function returns an error for value.

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Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIObjectUnpin()
Unpins an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectFree()
Frees and unpins an object instance.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

Pin Count and Unpinning
Each object in the object cache has a pin count associated with it.

27.6.7 OCIObjectPinTable()
Pins a table object for a specified duration.
Purpose
Pins a table object for a specified duration.
Syntax
sword OCIObjectPinTable ( OCIEnv
OCIError
const OCISvcCtx
const OraText
ub4
const OraText
ub4
const OCIRef
OCIDuration
void

*env,
*err,
*svc,
*schema_name,
s_n_length,
*object_name,
o_n_length,
*scope_obj_ref,
pin_duration,
**object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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svc (IN)
The OCI service context handle.
schema_name (IN) [optional]
The schema name of the table.
s_n_length (IN) [optional]
The length of the schema name indicated in schema_name, in bytes.
object_name (IN)
The name of the table.
o_n_length (IN)
The length of the table name specified in object_name, in bytes.
scope_obj_ref (IN) [optional]
The reference of the scoping object.
pin_duration (IN)
The pin duration.

See Also:
OCIObjectPin()

object (OUT)
The pinned table object.
Comments
This function pins a table object with the specified pin duration. The client can unpin
the object by calling OCIObjectUnpin().
The table object pinned by this call can be passed as a parameter to OCIObjectNew() to
create a standalone persistent object.

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIObjectUnpin()
Unpins an object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectNew()
Creates a standalone instance.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.6.8 OCIObjectUnpin()
Unpins an object.
Purpose
Unpins an object.
Syntax
sword OCIObjectUnpin ( OCIEnv
OCIError
void

*env,
*err,
*object );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
object (IN)
A pointer to an object, which must already be pinned.
Comments
There is a pin count associated with each object, which is incremented whenever an
object is pinned. When the pin count of the object is zero, the object is said to be
completely unpinned. An unpinned object can be freed implicitly by OCI at any time
without error.
This function unpins an object. An object is completely unpinned when any of the
following is true:
•

The object's pin count reaches zero (that is, it is unpinned a total of n times after
being pinned a total of n times).

•

It is the end of the object's pin duration.

•

The function OCIObjectPinCountReset() is called on the object.

When an object is completely unpinned, it can be freed implicitly by OCI at any time
without error.

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The following rules apply to unpinning different types of objects:
For Persistent Objects
When a persistent object is completely unpinned, it becomes a candidate for aging.
The memory of an object is freed when it is aged out. Aging is used to maximize the
utilization of memory. A dirty object cannot be aged out unless it is flushed.
For Transient Objects
The pin count of the object is decremented. A transient object can be freed only at the
end of its allocation duration or when it is explicitly deleted by calling OCIObjectFree().
For Values
This function returns an error for values.
Related Topics
•

OCIObjectPin()
Pins a referenceable object.

•

OCIObjectPinCountReset()
Completely unpins an object, setting its pin count to zero.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.7 OCI Type Information Accessor Functions
Lists and describes the OCI type information accessor functions.
Table 27-11 describes the OCI type information accessor functions that are described
in this section.
Table 27-11

Type Information Accessor Functions

Function

Purpose

OCITypeArrayByName()

Get an array of TDOs when given an array of
object names

OCITypeArrayByFullName()

Get an array of TDOs when given an array of
names for schema level or package level
types

OCITypeArrayByRef()

Get an array of TDOs when given an array of
object references

OCITypeByFullName()

Get a TDO when given a name for a schema
level or package level type

OCITypeByName()

Get a TDO when given an object name

OCITypeByRef()

Get a TDO when given an object reference

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Table 27-11

(Cont.) Type Information Accessor Functions

Function

Purpose

OCITypePackage()

Get the package name of a type if it is a
package type

27.7.1 OCITypeArrayByName()
Gets an array of TDOs when given an array of names.
Purpose
Gets an array of TDOs when given an array of names.

Note:
OCITypeArrayByName() does not support package level types.

Syntax
sword OCITypeArrayByName ( OCIEnv
OCIError
const OCISvcCtx
ub4
const OraText
ub4
const OraText
ub4
const OraText
ub4
OCIDuration
OCITypeGetOpt
OCIType

*envhp,
*errhp,
*svc,
array_len,
*schema_name[],
s_length[],
*type_name[],
t_length[],
*version_name[],
v_length[],
pin_duration,
get_option,
*tdo[] );

Parameters
envhp (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service handle.
array_len (IN)
Number of schema_name or type_name or version_name entries to be retrieved.

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schema_name (IN, optional)
Array of schema names associated with the types to be retrieved. The array must
have array_len elements if specified. If 0 is supplied, the default schema is assumed;
otherwise, schema_name must have array_len number of elements. Zero (0) can be
supplied for one or more of the entries to indicate that the default schema is desired
for those entries.
s_length (IN)
Array of schema_name lengths with each entry corresponding to the length of the
corresponding schema_name entry in the schema_name array in bytes. The array must
either have array_len number of elements or it must be 0 if schema_name is not
specified.
type_name (IN)
Array of the names of the types to retrieve. This must have array_len number of
elements.
t_length (IN)
Array of the lengths of type names in the type_name array in bytes.
version_name (IN)
The version name is ignored and the latest version of the requested type is returned.
Because type evolution was available starting in release 9.0, pre-9.0 applications
attempting to access an altered type generate an error. These applications must be
modified, recompiled, and relinked using the latest type definition.
Array of the version names of the types to retrieve corresponding. This can be 0 to
indicate retrieval of the most current versions, or it must have array_len number of
elements.
If 0 is supplied, the most current version is assumed, otherwise it must have array_len
number of elements. Zero (0) can be supplied for one or more of the entries to
indicate that the current version is desired for those entries.
v_length (IN)
Array of the lengths of version names in the version_name array in bytes.
pin_duration (IN)
Pin duration (for example, until the end of the current transaction) for the types
retrieved. See oro.h for a description of each option.
get_option (IN)
Option for loading the types. It can be one of two values:
•

OCI_TYPEGET_HEADER (only the header is loaded)

•

OCI_TYPEGET_ALL (TDO and all ADO and MDOs are loaded)

tdo (OUT)
Output array for the pointers to each pinned type in the object cache. It must have
space for array_len pointers. Use OCIObjectGetObjectRef() to obtain the CREF to each
pinned type descriptor.
Comments
Gets pointers to the existing types associated with the schema or type name array.
You can use the get_option parameter to control the portion of the TDO that gets
loaded for each round-trip.

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This function returns an error if any of the required parameters is NULL or any object
types associated with a schema or type name entry do not exist.
To retrieve a single type, rather than an array, use OCITypeByName().

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCITypeArrayByRef()
Gets an array of TDOs when given an array of references.

•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectGetObjectRef()
Returns a reference to a given persistent object.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.7.2 OCITypeArrayByFullName()
Gets the most current version of an existing array of TDOs when given an array of
names for schema level or package level types.
Purpose
Gets the most current version of an existing array of TDOs when given an array of
names for schema level or package level types.

Note:
OCITypeArrayByFullName() is the array version of OCITypeByFullName(). This
means that these two functions are functionally identical and one implements
OCITypeArrayByFullName() using OCITypeByName() and vice versa.

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Syntax
sword OCITypeArrayByFullName( OCIEnv
OCIError
const OCISvcCtx
ub4
const oratext
ub4
const oratext
ub4
OCIDuration
OCITypeGetOpt
OCIType

*env,
*err,
*svc,
array_len,
*full_type_name[],
f_t_length[],
*version_name[],
v_length[],
pin_duration,
get_option,
*tdo[])

Parameters
envhp (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service handle.
array_len (IN)
Number of schema_name or type_name or version_name entries to be retrieved.
full_type_name (IN)
The name of the type. If the full_type_name is not fully qualified, name resolution will
determine the type inferred. For example, SCOTT.MYPACK.MYTYPE would refer to type
MYTYPE in package MYPACK. If the current schema is SCOTT, this could also be
MYPACK.MYTYPE. See Oracle Database PL/SQL Language Reference for more
information about PL/SQL name resolution.
This also applies for schema level types. The string could be SCOTT.MYTYPE or simply
MYTYPE to specify a schema level type.
f_t_length (IN)
Length of full_type_name in bytes.
version_name (IN)
The version name is ignored and the latest version of the requested type is returned.
Because type evolution was available starting in release 9.0, pre-9.0 applications
attempting to access an altered type generate an error. These applications must be
modified, recompiled, and relinked using the latest type definition.
Array of the version names of the types to retrieve corresponding. This can be 0 to
indicate retrieval of the most current versions, or it must have array_len number of
elements.
If 0 is supplied, the most current version is assumed, otherwise it must have array_len
number of elements. Zero (0) can be supplied for one or more of the entries to
indicate that the current version is desired for those entries.

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v_length (IN)
Array of the lengths of version names in the version_name array in bytes.
pin_duration (IN)
Pin duration (for example, until the end of the current transaction) for the types
retrieved. See oro.h for a description of each option.
get_option (IN)
Option for loading the types. It can be one of two values:
•

OCI_TYPEGET_HEADER (only the header is loaded)

•

OCI_TYPEGET_ALL (TDO and all ADO and MDOs are loaded)

tdo (OUT)
Output array for the pointers to each pinned type in the object cache. It must have
space for array_len pointers. Use OCIObjectGetObjectRef() to obtain the CREF to each
pinned type descriptor.
Comments
Gets pointers to the existing types associated with the schema or package type name
array.
You can use the get_option parameter to control the portion of the TDO that gets
loaded for each round-trip.
This function returns an error if any of the required parameters is NULL or any object
types associated with a schema or package type name entry do not exist.
To retrieve a single type, rather than an array, use OCITypeByFullName().

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCITypeArrayByRef()
Gets an array of TDOs when given an array of references.

•

OCITypeByFullName()
Gets the most current version of an existing TDO when given a name for a
schema level or package level type.

•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCITypePackage()
Returns the package name of a type if it is a package type.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectGetObjectRef()
Returns a reference to a given persistent object.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.7.3 OCITypeArrayByRef()
Gets an array of TDOs when given an array of references.
Purpose
Gets an array of TDOs when given an array of references.
Syntax
sword OCITypeArrayByRef ( OCIEnv
OCIError
ub4
const OCIRef
OCIDuration
OCITypeGetOpt
OCIType

*envhp,
*errhp,
array_len,
*type_ref[],
pin_duration,
get_option,
*tdo[] );

Parameters
envhp (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
array_len (IN)
Number of schema_name or type_name or version_name entries to be retrieved.
type_ref (IN)
Array of OCIRef * pointing to the particular version of the type descriptor object to
obtain. The array must have array_len elements if specified.
pin_duration (IN)
Pin duration (for example, until the end of the current transaction) for the types
retrieved. See oro.h for a description of each option.
get_option (IN)
Option for loading the types. It can be one of two values:
•

OCI_TYPEGET_HEADER (only the header is loaded)

•

OCI_TYPEGET_ALL (TDO and all ADO and MDOs are loaded)

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tdo (OUT)
Output array for the pointers to each pinned type in the object cache. It must have
space for array_len pointers. Use OCIObjectGetObjectRef() to obtain the CREF to each
pinned type descriptor.
Comments
Gets pointers to the existing types with the schema or type name array.
This function returns an error if:
•

Any of the required parameters is NULL

•

One or more object types associated with a schema or type name entry does not
exist

To retrieve a single type, rather than an array of types, use OCITypeByRef().

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCITypeArrayByName()
Gets an array of TDOs when given an array of names.

•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectGetObjectRef()
Returns a reference to a given persistent object.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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27.7.4 OCITypeByFullName()
Gets the most current version of an existing TDO when given a name for a schema
level or package level type.
Purpose
Gets the most current version of an existing TDO when given a name for a schema
level or package level type.
Syntax
sword OCITypeByFullName(OCIEnv
*env,
OCIError
*err,
const OCISvcCtx *svc,
const oratext *full_type_name,
ub4
f_t_length,
const oratext *version_name,
ub4
v_length,
OCIDuration
pin_duration,
OCITypeGetOpt
get_option,
OCIType
**tdo);

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service handle.
full_type_name (IN)
The name of the type. If the full_type_name is not fully qualified, name resolution will
determine the type inferred. Thus, the full path name to the object can include the
schema, package name, and type name. For example, SCOTT.MYPACK.MYTYPE would
refer to type MYTYPE in package MYPACK. If the current schema is SCOTT, this could also
be MYPACK.MYTYPE. See Oracle Database PL/SQL Language Reference for more
information about PL/SQL name resolution.
This also applies for schema level types. The string could be SCOTT.MYTYPE or simply
MYTYPE to specify a schema level type.
f_t_length (IN)
Length of full_type_name in bytes.
version_name (IN)
The version name is ignored and the latest version of the requested type is returned.
Because type evolution was available starting in release 9.0, pre-9.0 applications
attempting to access an altered type generate an error. These applications must be
modified, recompiled, and relinked using the latest type definition.

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User-readable version of the type. Pass as (text *)0 to retrieve the most current
version.
v_length (IN)
Length of version_name in bytes.
pin_duration (IN)
Pin duration.

See Also:
Object Duration
get_option ((IN)
Option for loading the types. It can be one of two values:
•

OCI_TYPEGET_HEADER (only the header is loaded)

•

OCI_TYPEGET_ALL (TDO and all ADO and MDOs are loaded)

tdo (OUT)
Pointer to the pinned type in the object cache.
Comments
The fact that the type name is passed as a single string also enables other clients and
drivers, such as thick-client JDBC, to easily resolve type names contained in a single
name string.
Package types which contain remote package type fields will not be supported by
OCITypeByFullName(). Any attempt to get a package type, which contains a remote
package type field, results in an error.
This function gets a pointer to the existing type associated with the schema or
package type name. It returns an error if any of the required parameters is NULL, or if
the object type associated with the schema or package type name does not exist, or if
version_name does not exist.

Note:
Schema and package type names are case-sensitive. If they have been
created with SQL, you must use strings in all uppercase, or the program
stops.

This function always makes a round-trip to the server. Therefore calling this function
repeatedly to get the type can significantly reduce performance. To minimize the
round-trips, the application can call the function for each type and cache the type
objects.
To free the type obtained by this function, call OCIObjectUnpin() or
OCIObjectPinCountReset().

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An application can retrieve an array of TDOs by calling OCITypeArrayByName() or
OCITypeArrayByRef().

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCITypeArrayByFullName()
Gets the most current version of an existing array of TDOs when given an array of
names for schema level or package level types.

•

OCITypeArrayByRef()
Gets an array of TDOs when given an array of references.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectUnpin()
Unpins an object.

•

OCIObjectPinCountReset()
Completely unpins an object, setting its pin count to zero.

•

OCITypeArrayByName()
Gets an array of TDOs when given an array of names.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.7.5 OCITypeByName()
Gets the most current version of an existing TDO.
Purpose
Gets the most current version of an existing TDO. This call does not support package
level types. The name of the schema and the name of the type are each entered in
separate strings.
Syntax
sword OCITypeByName ( OCIEnv
OCIError

*env,
*err,

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const OCISvcCtx
const OraText
ub4
const OraText
ub4
const OraText
ub4
OCIDuration
OCITypeGetOpt
OCIType

*svc,
*schema_name,
s_length,
*type_name,
t_length,
*version_name,
v_length,
pin_duration,
get_option
**tdo );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
svc (IN)
OCI service handle.
schema_name (IN, optional)
Name of schema associated with the type. By default, the user's schema name is
used. This string must be all uppercase, or OCI throws an internal error and the
program stops.
s_length (IN)
Length of the schema_name parameter, in bytes.
type_name (IN)
Name of the type to get. This string must be all uppercase, or OCI throws an internal
error and the program stops.
t_length (IN)
Length of the type_name parameter, in bytes.
version_name (IN)
The version name is ignored and the latest version of the requested type is returned.
Because type evolution was available starting in release 9.0, pre-9.0 applications
attempting to access an altered type generate an error. These applications must be
modified, recompiled, and relinked using the latest type definition.
User-readable version of the type. Pass as (text *)0 to retrieve the most current
version.
v_length (IN)
Length of version_name in bytes.
pin_duration (IN)
Pin duration.

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See Also:
Object Duration
get_option ((IN)
Option for loading the types. It can be one of two values:
•

OCI_TYPEGET_HEADER (only the header is loaded)

•

OCI_TYPEGET_ALL (TDO and all ADO and MDOs are loaded)

tdo (OUT)
Pointer to the pinned type in the object cache.
Comments
This function gets a pointer to the existing type associated with the schema or type
name. It returns an error if any of the required parameters is NULL, or if the object type
associated with the schema or type name does not exist, or if version_name does not
exist.

Note:
Schema and type names are case-sensitive. If they have been created with
SQL, you must use strings in all uppercase, or the program stops.

This function always makes a round-trip to the server. Therefore calling this function
repeatedly to get the type can significantly reduce performance. To minimize the
round-trips, the application can call the function for each type and cache the type
objects.
To free the type obtained by this function, call OCIObjectUnpin() or
OCIObjectPinCountReset().

An application can retrieve an array of TDOs by calling OCITypeArrayByName() or
OCITypeArrayByRef().

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCITypeByRef()
Gets a TDO when given a reference.

•

OCITypeArrayByName()
Gets an array of TDOs when given an array of names.

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•

OCITypeArrayByRef()
Gets an array of TDOs when given an array of references.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIObjectUnpin()
Unpins an object.

•

OCIObjectPinCountReset()
Completely unpins an object, setting its pin count to zero.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.7.6 OCITypeByRef()
Gets a TDO when given a reference.
Purpose
Gets a TDO when given a reference.
Syntax
sword OCITypeByRef ( OCIEnv
*env,
OCIError
*err,
const OCIRef
*type_ref,
OCIDuration
pin_duration,
OCITypeGetOpt
get_option,
OCIType
**tdo );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
type_ref (IN)
An OCIRef * pointing to the version of the type descriptor object to obtain.
pin_duration (IN)
Pin duration until the end of the current transaction for the type to retrieve. See oro.h
for a description of each option.
get_option (IN)
Option for loading the type. It can be one of two values:

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•

OCI_TYPEGET_HEADER (only the header is loaded)

•

OCI_TYPEGET_ALL (TDO and all ADO and MDOs are loaded)

tdo (OUT)
Pointer to the pinned type in the object cache.
Comments
OCITypeByRef() returns an error if any of the required parameters is NULL.

Note:
The TDO (array of TDOs or table definition) obtained by this function belongs
to the logical partition of the cache corresponding to the service handle
(connection) passed in. If TDOs or tables are used across logical partitions,
then the behavior is not known and may change between releases.

Related Topics
•

OCITypeByName()
Gets the most current version of an existing TDO.

•

OCITypeArrayByName()
Gets an array of TDOs when given an array of names.

•

OCITypeArrayByRef()
Gets an array of TDOs when given an array of references.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

27.7.7 OCITypePackage()
Returns the package name of a type if it is a package type.
Purpose
Returns the package name of a type if it is a package type.
Syntax
oratext* OCITypePackage( OCIEnv
OCIError
const OCIType
ub4

*env,
*err,
*tdo,
*n_length);

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tdo (OUT)
Pointer to the pinned type in the object cache.
n_length
Length of the package name, in bytes.
Comments
If the type is not a package type, the return value will be null and n_length will be zero.
Related Topics
•

OCITypeArrayByFullName()
Gets the most current version of an existing array of TDOs when given an array of
names for schema level or package level types.

•

OCITypeByFullName()
Gets the most current version of an existing TDO when given a name for a
schema level or package level type.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28
OCI Data Type Mapping and Manipulation
Functions
This chapter describes the OCI data type mapping and manipulation functions.
These functions are Oracle's external C language interface to Oracle Database
predefined types.

See Also:
For code examples, see the demonstration programs included with your
Oracle Database installation. For additional information, see OCI
Demonstration Programs.

This chapter contains these topics:
•

Introduction to Data Type Mapping and Manipulation Functions

•

OCI Collection and Iterator Functions

•

OCI Date, Datetime, and Interval Functions

•

OCI NUMBER Functions

•

OCI Raw Functions

•

OCI REF Functions

•

OCI String Functions

•

OCI Table Functions

28.1 Introduction to Data Type Mapping and Manipulation
Functions
Introduces detailed information about OCI data type mapping and manipulation
functions.
This section describes the OCI data type mapping and manipulation functions in detail.

See Also:
Object-Relational Data Types in OCI for more information about the functions
listed in this chapter

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28.1.1 Conventions for OCI Functions
Reports the conventions used for describing OCI functions.
See the Conventions for OCI Functions for the conventions used in describing each
function. The entries for each function may also contain the following information:

28.1.2 Returns
Describes the value returned by the function.
A description of what value is returned by the function if the function returns something
other than the standard return codes listed in "Table 28-1".

28.1.3 Data Type Mapping and Manipulation Function Return Values
Describes the function return values.
The OCI data type mapping and manipulation functions typically return one of the
values shown in Table 28-1.
Table 28-1

Function Return Values

Return Value

Meaning

OCI_SUCCESS

The operation succeeded.

OCI_ERROR

The operation failed. The specific error can be
retrieved by calling OCIErrorGet() on the error handle
passed to the function.

OCI_INVALID_HANDLE

The OCI handle passed to the function is invalid.

See Also:
Error Handling in OCI for more information about return codes and error
handling

28.1.4 Functions Returning Other Values
Lists functions returning values directly from the function call.
Some functions return values other than those listed in Table 28-1. When you use the
following functions, consider that they return a value directly from the function call,
rather than through an OUT parameter.
•

OCICollMax()

•

OCIRawPtr()

•

OCIRawSize()

•

OCIRefHexSize()

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•

OCIRefIsEqual()

•

OCIRefIsNull()

•

OCIStringPtr()

•

OCIStringSize()

28.1.5 Server Round-Trips for Data Type Mapping and Manipulation
Functions
Indicates the number of server round-trips required for individual OCI data type
mapping and manipulation functions.
For a table showing the number of server round-trips required for individual OCI data
type mapping and manipulation functions, see Table C-5.

28.1.6 Examples
Describes information about the examples.
For more information about these functions, including some code examples, see
Object-Relational Data Types in OCI.

28.2 OCI Collection and Iterator Functions
Lists and describes the OCI collection and iterator functions.
Table 28-2 describes the OCI collection and iterator functions that are described in this
section.
Table 28-2

Collection and Iterator Functions

Function

Purpose

OCICollAppend()

Append an element to the end of a collection

OCICollAssign()

Assign (deep copy) one collection to another

OCICollAssignElem()

Assign the given element value elem to the
element at coll[index]

OCICollGetElem()

Get pointer to an element

OCICollGetElemArray()

Get an array of elements from a collection

OCICollIsLocator()

Indicate whether a collection is locator-based
or not

OCICollMax()

Return maximum number of elements in
collection

OCICollSize()

Get current size of collection (in number of
elements)

OCICollTrim()

Trim elements from the collection

OCIIterCreate()

Create iterator to scan the varray elements

OCIIterDelete()

Delete iterator

OCIIterGetCurrent()

Get current collection element

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Table 28-2

(Cont.) Collection and Iterator Functions

Function

Purpose

OCIIterInit()

Initialize iterator to scan the given collection

OCIIterNext()

Get next collection element

OCIIterPrev()

Get previous collection element

28.2.1 OCICollAppend()
Appends an element to the end of a collection.
Purpose
Appends an element to the end of a collection.
Syntax
sword OCICollAppend ( OCIEnv
OCIError
const void
const void
OCIColl

*env,
*err,
*elem,
*elemind,
*coll );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
elem (IN)
Pointer to the element to be appended to the end of the given collection.
elemind (IN) [optional]
Pointer to the element's NULL indicator information. If (elemind == NULL) then the NULL
indicator information of the appended element is set to non-NULL.
coll (IN/OUT)
Updated collection.
Comments
Appending an element is equivalent to increasing the size of the collection by one
element and updating (deep copying) the last element's data with the given element's
data. Note that the pointer to the given element elem is not saved by this function,
which means that elem is strictly an input parameter.
OCICollAppend() creates an element at index 0 if no elements exist. The method (array

bind) for binding PL/SQL index-by tables assumes a start index of 1.

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Returns
This function returns an error if the current size of the collection equals the maximum
size (upper bound) of the collection before appending the element. This function also
returns an error if any of the input parameters is NULL.
Related Topics
•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.2 OCICollAssign()
Assigns (deep copies) one collection to another.
Purpose
Assigns (deep copies) one collection to another.
Syntax
sword OCICollAssign ( OCIEnv
OCIError
const OCIColl
OCIColl

*env,
*err,
*rhs,
*lhs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
rhs (IN)
Right-hand side (source) collection to be assigned from.
lhs (OUT)
Left-hand side (target) collection to be assigned to.
Comments
Assigns rhs (source) to lhs (target). The lhs collection may be decreased or increased
depending upon the size of rhs. If the lhs collection contains any elements, then the

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elements are deleted before the assignment. This function performs a deep copy. The
memory for the elements comes from the object cache.
Returns
An error is returned if the element types of the lhs and rhs collections do not match.
Also, an error is returned if the upper bound of the lhs collection is less than the
current number of elements in the rhs collection. An error is also returned if:
•

Any of the input parameters is NULL

•

There is a type mismatch between the lhs and rhs collections

•

The upper bound of the lhs collection is less than the current number of elements
in the rhs collection

Related Topics
•

OCICollAssignElem()
Assigns the given element value elem to the element at coll[index].

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.3 OCICollAssignElem()
Assigns the given element value elem to the element at coll[index].
Purpose
Assigns the given element value elem to the element at coll[index].
Syntax
sword OCICollAssignElem ( OCIEnv
OCIError
sb4
const void
const void
OCIColl

*env,
*err,
index,
*elem,
*elemind,
*coll );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
index (IN)
Index of the element to which the element is assigned.
elem (IN)
Source element from which the element is assigned. See Table 24-1 that lists the type
of data and what C data type can be found in parameter elem.
elemind (IN) [optional]
Pointer to the element's NULL indicator information; if (elemind == NULL), then the NULL
indicator information of the assigned element is set to non-NULL.
coll (IN/OUT)
Collection to be updated.
Comments
If the collection is of type nested table, the element at the given index might not exist,
as when an element has been deleted. In this case, the given element is inserted at
index. Otherwise, the element at index is updated with the value of elem.
Note that the given element is deep copied, and elem is strictly an input parameter.
Returns
This function returns an error if any input parameter is NULL or if the given index is
beyond the bounds of the given collection.
Related Topics
•

OCICollAssign()
Assigns (deep copies) one collection to another.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.4 OCICollGetElem()
Gets a pointer to the element at the given index.
Purpose
Gets a pointer to the element at the given index.

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Syntax
sword OCICollGetElem ( OCIEnv
OCIError
const OCIColl
sb4
boolean
void
void

*env,
*err,
*coll,
index,
*exists,
**elem,
**elemind );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
coll (IN)
Pointer to the element in this collection to be returned.
index (IN)
Index of the element whose pointer is returned.
exists (OUT)
Set to FALSE if the element at the specified index does not exist; otherwise, set to TRUE.
elem (OUT)
Address of the element to be returned.
elemind (OUT) [optional]
Address of the NULL indicator information is returned. If (elemind == NULL), then the NULL
indicator information is not returned.
Comments
Gets the address of the element at the given position. Optionally, this function also
returns the address of the element's NULL indicator information.
Table 28-3 describes for each OCI type code value, the element pointer type, and
what the corresponding collection element type is. The element pointer is returned with
the elem parameter of OCICollGetElem(). See the table for object data type mappings
for object type attributes in About Mapping Object Data Types to Cfor a more complete
list of the OCITypeCode values.
Table 28-3

Element Pointers

OCITypeCode Values

*elem Is Set to

Element Type

OCI_TYPECODE_NUMBER

OCINumber*

Oracle NUMBER (OCINumber)

OCI_TYPECODE_DATE

OCIDate*

Date (OCIDate)

OCI_TYPECODE_TIMESTAMP

OCIDateTime*

Datetime (OCIDateTime)

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Table 28-3

(Cont.) Element Pointers

OCITypeCode Values

*elem Is Set to

Element Type

OCI_TYPECODE_INTERVAL_YM,
OCI_TYPECODE_INTERVAL_DS

OCIInterval*

Interval (OCIInterval)

OCI_TYPECODE_CHAR (n),
OCI_TYPECODE_NCHAR

OCIString**

Variable-length string (OCIString*)

OCI_TYPECODE_RAW

OCIRaw**

Variable-length raw (OCIRaw*)

OCI_TYPECODE_REF

OCIRef**

Object reference (OCIRef*)

OCI_TYPECODE_BLOB,
OCI_TYPECODE_CLOB,
OCI_TYPECODE_NCLOB

OCILobLocator**

Lob locator (OCILobLocator*)

OCI_TYPECODE_OBJECT

person*

Object type (such as person)

OCI_TYPECODE_NAMEDCOLLECTION

OCIColl *

Collections

The element pointer returned by OCICollGetElem() is in a form that can be used not
only to access the element data but also to serve as the target (left-hand side) of an
assignment statement.
For example, assume the user is iterating over the elements of a collection whose
element type is object reference (OCIRef*). A call to OCICollGetElem() returns the
pointer to a reference handle (OCIRef**). After getting the pointer to the collection
element, you may want to modify it by assigning a new reference.
The following code example shows how this can be accomplished with the
OCIRefAssign() function.
Assigning a New Reference to the Pointer to the Collection Element
sword OCIRefAssign( OCIEnv
OCIError
const OCIRef
OCIRef

*env,
*err,
*source,
**target );

Note that the target parameter of OCIRefAssign() is of type OCIRef**. Hence
OCICollGetElem() returns OCIRef**. If *target equals NULL, a new REF is allocated by
OCIRefAssign() and returned in the target parameter.
Similarly, if the collection element was of type string (OCIString*), OCICollGetElem()
returns the pointer to the string handle (that is, OCIString**). If a new string is
assigned, through OCIStringAssign() or OCIStringAssignText(), the type of the target
must be OCIString **.
If the collection element is of type Oracle NUMBER, OCICollGetElem() returns OCINumber*.
The following code example shows the prototype of the OCINumberAssign() call.
Prototype of OCINumberAssign() Call
sword OCINumberAssign(OCIError
*err,
const OCINumber *from,
OCINumber
*to);

Returns
The OCICollGetElem() function returns an error if any of the input parameters is NULL.

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Related Topics
•

OCICollAssignElem()
Assigns the given element value elem to the element at coll[index].

•

OCIRefAssign()
Assigns one REF to another, such that both reference the same object.

•

OCIStringAssign()
Assigns one string to another string.

•

OCIStringAssignText()
Assigns the source text string to the target string.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.5 OCICollGetElemArray()
Gets an array of elements from a collection when given a starting index.
Purpose
Gets an array of elements from a collection when given a starting index.
Syntax
sword OCICollGetElemArray ( OCIEnv
OCIError
const OCIColl
sb4
boolean
void
void
uword

*env,
*err,
*coll,
index,
*exists,
**elem,
**elemind,
*nelems );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
coll (IN)
Pointers to the elements in this collection to be returned.

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index (IN)
Starting index of the elements.
exists (OUT)
Is set to FALSE if the element at the specified index does not exist; otherwise, it is set
to TRUE.
elem (OUT)
Address of the desired elements to be returned.
elemind (OUT) [optional]
Address of the NULL indicator information to be returned. If (elemind == NULL), then the
NULL indicator information is not returned.
nelems (IN)
Maximum number of pointers to both elem and elemind.
Comments
Gets the address of the elements from the given position.
For index by integer collections, OCICollGetElemArray() gets the elements beginning at
the given index, but loses the index information for each element in the process. Users
are able to get the element data beginning at that index as an array, but cannot get the
index for each element in the array. This behavior is similar to what happens for the
OCIIterCreate(), OCIIterDelete(), OCIIterGetCurrent(), OCIIterInit(), OCIIterNext(),
and OCIIterPrev() functions.
Returns
Optionally, this function also returns the address of the element's NULL indicator
information.
Related Topics
•

OCICollGetElem()
Gets a pointer to the element at the given index.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterCreate()
Creates an iterator to scan the elements or the collection.

•

OCIIterDelete()
Deletes a collection iterator.

•

OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.

•

OCIIterInit()
Initializes an iterator to scan a collection.

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•

OCIIterNext()
Gets a pointer to the next iterator collection element.

•

OCIIterPrev()
Gets a pointer to the previous iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.6 OCICollIsLocator()
Indicates whether a collection is locator-based or not.
Purpose
Indicates whether a collection is locator-based or not.
Syntax
sword OCICollIsLocator ( OCIEnv
OCIError
const OCIColl
boolean

*env,
*err,
*coll,
*result );

Parameters
env (IN)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
coll (IN)
A collection item.
result (OUT)
Returns TRUE if the collection item is locator-based, FALSE otherwise.
Comments
This function tests to see whether a collection is locator-based.
Returns
Returns TRUE in the result parameter if the collection item is locator-based; otherwise,
it returns FALSE.
Related Topics
•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.7 OCICollMax()
Gets the maximum size in number of elements of the given collection.
Purpose
Gets the maximum size in number of elements of the given collection.
Syntax
sb4 OCICollMax ( OCIEnv
const OCIColl

*env,
*coll );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
coll (IN)
Collection whose number of elements is returned. The coll parameter must point to a
valid collection descriptor.
Comments
Returns the maximum number of elements that the given collection can hold. A value
of zero indicates that the collection has no upper bound.
For collections that do not support negative indexes, the largest index number is also
the maximum size of the collection. However, this is not true for index-by integer
collections because some of the elements can have negative indexes, so the largest
index numbered element is not the same as the maximum collection size.
Returns
The upper bound of the given collection.
The return value is always 0 (no upper bound) for index-by integer collections.
Related Topics
•

OCICollSize()
Gets the current size in number of elements of the given collection.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.8 OCICollSize()
Gets the current size in number of elements of the given collection.
Purpose
Gets the current size in number of elements of the given collection.
Syntax
sword OCICollSize ( OCIEnv
OCIError
const OCIColl
sb4

*env,
*err,
*coll
*size );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
coll (IN)
Collection whose number of elements is returned. Must point to a valid collection
descriptor.
size (OUT)
Current number of elements in the collection.
Comments
Returns the current number of elements in the given collection. For a nested table, this
count is not decremented when elements are deleted. So, this count includes any
holes created by deleting elements. A trim operation (OCICollTrim()) decrements the
count by the number of trimmed elements. To get the count minus the deleted
elements use OCITableSize().
The following pseudocode shows some examples:
OCICollSize(...);
// assume 'size' returned is equal to 5
OCITableDelete(...); // delete one element
OCICollSize(...);
// 'size' returned is still 5

To get the count minus the deleted elements use OCITableSize(). Continuing the
earlier example:

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OCITableSize(...)
// 'size' returned is equal to 4

A trim operation OCICollTrim()) decrements the count by the number of trimmed
elements. Continuing the earlier example:
OCICollTrim(..,1..); // trim one element
OCICollSize(...);
// 'size' returned is equal to 4

Returns
The OCICollSize() function returns an error if an error occurs during the loading of the
collection into the object cache or if any of the input parameters is NULL.
Related Topics
•

OCICollMax()
Gets the maximum size in number of elements of the given collection.

•

OCICollTrim()
Trims the given number of elements from the end of the collection.

•

OCITableSize()
Returns the size of the given table, not including any holes created by deleted
elements.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.9 OCICollTrim()
Trims the given number of elements from the end of the collection.
Purpose
Trims the given number of elements from the end of the collection.
Syntax
sword OCICollTrim ( OCIEnv
OCIError
sb4
OCIColl

*env,
*err,
trim_num,
*coll );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
trim_num (IN)
Number of elements to trim.
coll (IN/OUT)
Removes (frees) trim_num of elements from the end of the collection coll.
Comments
The elements are removed from the end of the collection.
Returns
An error is returned if trim_num is greater than the current size of the collection.
Related Topics
•

OCICollSize()
Gets the current size in number of elements of the given collection.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.10 OCIIterCreate()
Creates an iterator to scan the elements or the collection.
Purpose
Creates an iterator to scan the elements or the collection.
Syntax
sword OCIIterCreate ( OCIEnv
OCIError
const OCIColl
OCIIter

*env,
*err,
*coll,
**itr );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
coll (IN)
Collection that is scanned. For Oracle8i or later, valid collection types include varrays
and nested tables.
itr (OUT)
Address to the allocated collection iterator to be returned by this function.
Comments
The iterator is created in the object cache. The iterator is initialized to point to the
beginning of the collection.
If OCIIterNext() is called immediately after creating the iterator, then the first element
of the collection is returned. If OCIIterPrev() is called immediately after creating the
iterator, then an "at beginning of collection" error is returned.
For index-by integer collections, the OCIIterCreate(), OCIIterDelete(),
OCIIterGetCurrent(), OCIIterInit(), OCIIterNext(), and OCIIterPrev() functions all
ignore the index for each element in the collection. That is, OCIIterGetCurrent() returns
only the element value and not the index of the element.
Returns
This function returns an error if any of the input parameters is NULL.
Related Topics
•

OCIIterDelete()
Deletes a collection iterator.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.

•

OCIIterInit()
Initializes an iterator to scan a collection.

•

OCIIterNext()
Gets a pointer to the next iterator collection element.

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•

OCIIterPrev()
Gets a pointer to the previous iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.11 OCIIterDelete()
Deletes a collection iterator.
Purpose
Deletes a collection iterator.
Syntax
sword OCIIterDelete ( OCIEnv
OCIError
OCIIter

*env,
*err,
**itr );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
itr (IN/OUT)
The allocated collection iterator that is destroyed and set to NULL before returning.
Comments
Deletes an iterator that was previously created by a call to OCIIterCreate().
For index-by integer collections, the OCIIterCreate(), OCIIterDelete(),
OCIIterGetCurrent(), OCIIterInit(), OCIIterNext(), and OCIIterPrev() functions all
ignore the index for each element in the collection. That is, OCIIterGetCurrent() returns
only the element value and not the index of the element.
Returns
This function returns an error if any of the input parameters is NULL.
Related Topics
•

OCIIterCreate()
Creates an iterator to scan the elements or the collection.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.

•

OCIIterInit()
Initializes an iterator to scan a collection.

•

OCIIterNext()
Gets a pointer to the next iterator collection element.

•

OCIIterPrev()
Gets a pointer to the previous iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.12 OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.
Purpose
Gets a pointer to the current iterator collection element.
Syntax
sword OCIIterGetCurrent ( OCIEnv
OCIError
const OCIIter
void
void

*env,
*err,
*itr,
**elem,
**elemind );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
itr (IN)
Iterator that points to the current element.
elem (OUT)
Address of the element pointed to by the iterator to be returned. See Table 24-1 that
lists the type of data and what C data type can be found in parameter elem.
elemind (OUT) [optional]
Address of the element's NULL indicator information to be returned; if (elem_ind ==
NULL) then the NULL indicator information is not returned.

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Comments
Returns the pointer to the current iterator collection element and its corresponding NULL
information.
For index-by integer collections, the OCIIterCreate(), OCIIterGetCurrent(),
OCIIterInit(), OCIIterNext(), and OCIIterPrev() functions all ignore the index for each
element in the collection. That is, OCIIterGetCurrent() returns only the element value
and not the index of the element.
Returns
This function returns an error if any input parameter is NULL.
Related Topics
•

OCIIterCreate()
Creates an iterator to scan the elements or the collection.

•

OCIIterDelete()
Deletes a collection iterator.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterInit()
Initializes an iterator to scan a collection.

•

OCIIterNext()
Gets a pointer to the next iterator collection element.

•

OCIIterPrev()
Gets a pointer to the previous iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.13 OCIIterInit()
Initializes an iterator to scan a collection.
Purpose
Initializes an iterator to scan a collection.
Syntax
sword OCIIterInit ( OCIEnv
OCIError
const OCIColl
OCIIter

*env,
*err,
*coll,
*itr );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
coll (IN)
Collection that is scanned. For Oracle8i or later, valid collection types include varrays
and nested tables.
itr (IN/OUT)
Pointer to an allocated collection iterator.
Comments
Initializes at the given iterator to point to the beginning of the given collection. You can
use this function to perform either of the following tasks:
•

Reset an iterator to point back to the beginning of the collection.

•

Reuse an allocated iterator to scan a different collection.

For index-by integer collections, the OCIIterCreate(), OCIIterDelete(),
OCIIterGetCurrent(), OCIIterInit(), OCIIterNext(), and OCIIterPrev() functions all
ignore the index for each element in the collection. That is, OCIIterGetCurrent() returns
only the element value and not the index of the element.
Returns
Returns an error if any input parameter is NULL.
Related Topics
•

OCIIterCreate()
Creates an iterator to scan the elements or the collection.

•

OCIIterDelete()
Deletes a collection iterator.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.

•

OCIIterNext()
Gets a pointer to the next iterator collection element.

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•

OCIIterPrev()
Gets a pointer to the previous iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.14 OCIIterNext()
Gets a pointer to the next iterator collection element.
Purpose
Gets a pointer to the next iterator collection element.
Syntax
sword OCIIterNext ( OCIEnv
OCIError
OCIIter
void
void
boolean

*env,
*err,
*itr,
**elem,
**elemind,
*eoc);

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet()..
itr (IN/OUT)
Iterator that is updated to point to the next element.
elem (OUT)
Address of the next element; returned after the iterator is updated to point to it. See
Table 24-1 that lists the type of data and what C data type can be found in parameter
elem.
elemind (OUT) [optional]
Address of the element's NULL indicator information; if (elem_ind == NULL), then the NULL
indicator information is not returned.
eoc (OUT)
TRUE if the iterator is at the end of the collection (that is, the next element does not
exist); otherwise, FALSE.

Comments
This function returns a pointer to the next iterator collection element and its
corresponding NULL information. It also updates the iterator to point to the next
element.

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If the iterator is pointing to the last element of the collection before you execute this
function, then calling this function sets the eoc flag to TRUE. The iterator is left
unchanged in that case.
For index-by integer collections, the OCIIterCreate(), OCIIterDelete(),
OCIIterGetCurrent(), OCIIterInit(), OCIIterNext(), and OCIIterPrev() functions all
ignore the index for each element in the collection. That is, OCIIterGetCurrent() returns
only the element value and not the index of the element.
Returns
This function returns an error if any input parameter is NULL.
Related Topics
•

OCIIterCreate()
Creates an iterator to scan the elements or the collection.

•

OCIIterDelete()
Deletes a collection iterator.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.

•

OCIIterInit()
Initializes an iterator to scan a collection.

•

OCIIterPrev()
Gets a pointer to the previous iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.2.15 OCIIterPrev()
Gets a pointer to the previous iterator collection element.
Purpose
Gets a pointer to the previous iterator collection element.
Syntax
sword OCIIterPrev ( OCIEnv
OCIError
OCIIter
void
void
boolean

*env,
*err,
*itr,
**elem,
**elemind,
*boc );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
itr (IN/OUT)
Iterator that is updated to point to the previous element.
elem (OUT)
Address of the previous element; returned after the iterator is updated to point to it.
See Table 24-1 that lists the type of data and what C data type can be found in
parameter elem.
elemind (OUT) [optional]
Address of the element's NULL indicator information; if (elemind == NULL), then the NULL
indicator information is not returned.
boc (OUT)
TRUE if iterator is at the beginning of the collection (that is, the previous element does
not exist); otherwise, FALSE.

Comments
This function returns a pointer to the previous iterator collection element and its
corresponding NULL information. The iterator is updated to point to the previous
element.
If the iterator is pointing to the first element of the collection before you execute this
function, then calling this function sets boc to TRUE. The iterator is left unchanged in that
case.
For index-by integer collections, the OCIIterCreate(), OCIIterDelete(),
OCIIterGetCurrent(), OCIIterInit(), OCIIterNext(), and OCIIterPrev() functions all
ignore the index for each element in the collection. That is, OCIIterGetCurrent() returns
only the element value and not the index of the element.
Returns
This function returns an error if any input parameter is NULL.
Related Topics
•

OCIIterCreate()
Creates an iterator to scan the elements or the collection.

•

OCIIterDelete()
Deletes a collection iterator.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIIterGetCurrent()
Gets a pointer to the current iterator collection element.

•

OCIIterInit()
Initializes an iterator to scan a collection.

•

OCIIterNext()
Gets a pointer to the next iterator collection element.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3 OCI Date, Datetime, and Interval Functions
Lists and describes the OCI date and interval functions.
Table 28-4 describes the OCI date and interval functions that are described in this
section.
Table 28-4

Date Functions

Function

Purpose

OCIDateAddDays()

Add or subtract days

OCIDateAddMonths()

Add or subtract months

OCIDateAssign()

Assign date

OCIDateCheck()

Check if the given date is valid

OCIDateCompare()

Compare dates

OCIDateDaysBetween()

Get number of days between two
dates

OCIDateFromText()

Convert string to date

OCIDateGetDate()

Get the date portion of a date

OCIDateGetTime()

Get the time portion of a date

OCIDateLastDay()

Get date of last day of month

OCIDateNextDay()

Get date of next day

OCIDateSetDate()

Set the date portion of a date

OCIDateSetTime()

Set the time portion of a date

OCIDateSysDate()

Get the current system date and
time

OCIDateTimeAssign()

Perform a datetime assignment

OCIDateTimeCheck()

Check if the given date is valid

OCIDateTimeCompare()

Compare two datetime values

OCIDateTimeConstruct()

Construct a datetime descriptor

OCIDateTimeConvert()

Convert one datetime type to
another

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Table 28-4

(Cont.) Date Functions

Function

Purpose

OCIDateTimeFromArray()

Convert an array of size
OCI_DT_ARRAYLEN to an
OCIDateTime descriptor

OCIDateTimeFromText()

Convert the given string to Oracle
datetime type in the OCIDateTime
descriptor, according to the
specified format

OCIDateTimeGetDate()

Get the date (year, month, day)
portion of a datetime value

OCIDateTimeGetTime()

Get the time (hour, min, second,
fractional second) of a datetime
value

OCIDateTimeGetTimeZoneName()

Get the time zone name portion of a
datetime value

OCIDateTimeGetTimeZoneOffset()

Get the time zone (hour, minute)
portion of a datetime value

OCIDateTimeIntervalAdd()

Add an interval to a datetime to
produce a resulting datetime

OCIDateTimeIntervalSub()

Subtract an interval from a datetime
and store the result in a datetime

OCIDateTimeSubtract()

Take two datetimes as input and
store their difference in an interval

OCIDateTimeSysTimeStamp()

Get the system current date and
time as a time stamp with time zone

OCIDateTimeToArray()

Convert an OCIDateTime descriptor
to an array

OCIDateTimeToText()

Convert the given date to a string
according to the specified format

OCIDateToText()

Convert date to string

OCIDateZoneToZone()

Convert date from one time zone to
another zone

OCIIntervalAdd()

Add two intervals to produce a
resulting interval

OCIIntervalAssign()

Copy one interval to another

OCIIntervalCheck()

Check the validity of an interval

OCIIntervalCompare()

Compare two intervals

OCIIntervalDivide()

Divide an interval by an Oracle
NUMBER to produce an interval

OCIIntervalFromNumber()

Convert an Oracle NUMBER to an
interval

OCIIntervalFromText()

When given an interval string,
return the interval represented by
the string

OCIIntervalFromTZ()

Return an OCI_DTYPE_INTERVAL_DS

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Table 28-4

(Cont.) Date Functions

Function

Purpose

OCIIntervalGetDaySecond()

Get values of day, hour, minute,
and second from an interval

OCIIntervalGetYearMonth()

Get year and month from an interval

OCIIntervalMultiply()

Multiply an interval by an Oracle
NUMBER to produce an interval

OCIIntervalSetDaySecond()

Set day, hour, minute, and second
in an interval

OCIIntervalSetYearMonth()

Set year and month in an interval

OCIIntervalSubtract()

Subtract two intervals and stores
the result in an interval

OCIIntervalToNumber()

Convert an interval to an Oracle
NUMBER

OCIIntervalToText()

When given an interval, produce a
string representing the interval

28.3.1 OCIDateAddDays()
Adds or subtracts days from a given date.
Purpose
Adds or subtracts days from a given date.
Syntax
sword OCIDateAddDays ( OCIError
const OCIDate
sb4
OCIDate

*err,
*date,
num_days,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
he given date from which to add or subtract.
num_days (IN)
Number of days to be added or subtracted. A negative value is subtracted.
result (IN/OUT)
Result of adding days to, or subtracting days from, date.
Returns
This function returns an error if an invalid date is passed to it.

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Related Topics
•

OCIDateAddMonths()
Adds or subtracts months from a given date.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.2 OCIDateAddMonths()
Adds or subtracts months from a given date.
Purpose
Adds or subtracts months from a given date.
Syntax
sword OCIDateAddMonths ( OCIError
const OCIDate
sb4
OCIDate

*err,
*date,
num_months,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
The given date from which to add or subtract.
num_months (IN)
Number of months to be added or subtracted. A negative value is subtracted.
result (IN/OUT)
Result of adding days to, or subtracting days from, date.
Comments
If the input date is the last day of a month, then the appropriate adjustments are made
to ensure that the output date is also the last day of the month. For example, Feb. 28 +
1 month = March 31, and November 30 – 3 months = August 31. Otherwise the result
date has the same day component as date.
Returns
This function returns an error if an invalid date is passed to it.
Related Topics
•

OCIDateAddDays()
Adds or subtracts days from a given date.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.3 OCIDateAssign()
Performs a date assignment.
Purpose
Performs a date assignment.
Syntax
sword OCIDateAssign ( OCIError
const OCIDate
OCIDate

*err,
*from,
*to );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
from (IN)
Date to be assigned.
to (OUT)
Target of assignment.
Comments
This function assigns a value from one OCIDate variable to another.
Related Topics
•

OCIDateCheck()
Checks if the given date is valid.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.4 OCIDateCheck()
Checks if the given date is valid.
Purpose
Checks if the given date is valid.
Syntax
sword OCIDateCheck ( OCIError
const OCIDate
uword

*err,
*date,
*valid );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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date (IN)
Date to be checked.
valid (OUT)
Returns zero for a valid date; otherwise, it returns the logical operator OR combination
of all error bits specified in Table 28-5.
Table 28-5

Error Bits Returned by the valid Parameter for OCIDateCheck()

Macro Name

Bit Number

Error

OCI_DATE_INVALID_DAY

0x1

Bad day

OCI_DATE_DAY_BELOW_VALID

0x2

Bad day low/high bit (1=low)

OCI_DATE_INVALID_MONTH

0x4

Bad month

OCI_DATE_MONTH_BELOW_VALID

0x8

Bad month low/high bit (1=low)

OCI_DATE_INVALID_YEAR

0x10

Bad year

OCI_DATE_YEAR_BELOW_VALID

0x20

Bad year low/high bit (1=low)

OCI_DATE_INVALID_HOUR

0x40

Bad hour

OCI_DATE_HOUR_BELOW_VALID

0x80

Bad hour low/high bit (1=low)

OCI_DATE_INVALID_MINUTE

0x100

Bad minute

OCI_DATE_MINUTE_BELOW_VALID

0x200

Bad minute low/high bit (1=low)

OCI_DATE_INVALID_SECOND

0x400

Bad second

OCI_DATE_SECOND_BELOW_VALID

0x800

Bad second low/high bit (1=low)

OCI_DATE_DAY_MISSING_FROM_1582

0x1000

Day is one of those missing from
1582

OCI_DATE_YEAR_ZERO

0x2000

Year may not equal zero

OCI_DATE_INVALID_FORMAT

0x8000

Bad date format input

For example, if the date passed in was 2/0/1990 25:61:10 in (month/day/year
hours:minutes:seconds format), the error returned is:
OCI_DATE_INVALID_DAY | OCI_DATE_DAY_BELOW_VALID | OCI_DATE_INVALID_HOUR |
OCI_DATE_INVALID_MINUTE.

Returns
This function returns an error if date or valid pointer is NULL.
Related Topics
•

OCIDateCompare()
Compares two dates.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.5 OCIDateCompare()
Compares two dates.
Purpose
Compares two dates.
Syntax
sword OCIDateCompare ( OCIError
const OCIDate
const OCIDate
sword

*err,
*date1,
*date2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date1, date2 (IN)
Dates to be compared.
result (OUT)
Comparison result as listed in Table 28-6.
Table 28-6

Comparison Results

Comparison Result

Output in result Parameter

date1 < date2

-1

date1 = date2

0

date1 > date2

1

Returns
This function returns an error if an invalid date is passed to it.
Related Topics
•

OCIDateCheck()
Checks if the given date is valid.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.6 OCIDateDaysBetween()
Gets the number of days between two dates.
Purpose
Gets the number of days between two dates.

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Syntax
sword OCIDateDaysBetween ( OCIError
const OCIDate
const OCIDate
sb4

*err,
*date1,
*date2,
*num_days );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date1 (IN)
Input date.
date2 (IN)
Input date.
num_days (OUT)
Number of days between date1 and date2.
Comments
When the number of days between date1 and date2 is computed, the time is ignored.
Returns
This function returns an error if an invalid date is passed to it.
Related Topics
•

OCIDateCheck()
Checks if the given date is valid.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.7 OCIDateFromText()
Converts a character string to a date type according to the specified format.
Purpose
Converts a character string to a date type according to the specified format.
Syntax
sword OCIDateFromText ( OCIError
const OraText
ub4
const OraText
ub1
const OraText
ub4
OCIDate

*err,
*date_str,
d_str_length,
*fmt,
fmt_length,
*lang_name,
lang_length,
*date );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date_str (IN)
Input string to be converted to Oracle date.
d_str_length (IN)
Size of the input string. If the length is –1, then date_str is treated as a NULLterminated string.
fmt (IN)
Conversion format. If fmt is a NULL pointer, then the string is expected to be in "DDMON-YY" format.
fmt_length (IN)
Length of the fmt parameter.
lang_name (IN)
Language in which the names and abbreviations of days and months are specified. If
lang_name is a NULL string, (text *)0, then the default language of the session is used.
lang_length (IN)
Length of the lang_name parameter.
date (OUT)
Given string converted to date.
Comments
See the TO_DATE conversion function described in the Oracle Database SQL Language
Referencefor a description of format and multilingual arguments.
Returns
This function returns an error if it receives an invalid format, language, or input string.
Related Topics
•

OCIDateToText()
Converts a date type to a character string.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.8 OCIDateGetDate()
Gets the year, month, and day stored in an Oracle date.
Purpose
Gets the year, month, and day stored in an Oracle date.

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Syntax
void OCIDateGetDate ( const OCIDate
sb2
ub1
ub1

*date,
*year,
*month,
*day );

Parameters
date (IN)
Oracle date whose year, month, day data is retrieved.
year (OUT)
Year value returned.
month (OUT)
Month value returned.
day (OUT)
Day value returned.
Comments
None.
Related Topics
•

OCIDateSetDate()
Set the values in an Oracle date.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.9 OCIDateGetTime()
Gets the time stored in an Oracle date.
Purpose
Gets the time stored in an Oracle date.
Syntax
void OCIDateGetTime ( const OCIDate
ub1
ub1
ub1

*date,
*hour,
*min,
*sec );

Parameters
date (IN)
Oracle date whose time data is retrieved.
hour (OUT)
Hour value returned.

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min (OUT)
Minute value returned.
sec (OUT)
Second value returned.
Returns
Returns the time information in the form: hour, minute and seconds.
Related Topics
•

OCIDateSetTime()
Sets the time information in an Oracle date.

•

OCIDateGetDate()
Gets the year, month, and day stored in an Oracle date.

28.3.10 OCIDateLastDay()
Gets the date of the last day of the month in a specified date.
Purpose
Gets the date of the last day of the month in a specified date.
Syntax
sword OCIDateLastDay ( OCIError
const OCIDate
OCIDate

*err,
*date,
*last_day );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
Input date.
last_day (OUT)
Last day of the month in date.
Returns
This function returns an error if an invalid date is passed to it.
Related Topics
•

OCIDateGetDate()
Gets the year, month, and day stored in an Oracle date.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.11 OCIDateNextDay()
Gets the date of the next day of the week after a given date.
Purpose
Gets the date of the next day of the week after a given date.
Syntax
sword OCIDateNextDay ( OCIError
const OCIDate
const OraText
ub4
OCIDate

*err,
*date,
*day,
day_length,
*next_day );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
Returned date should be later than this date.
day (IN)
First day of the week named by this is returned.
day_length (IN)
Length in bytes of string day.
next_day (OUT)
First day of the week named by day that is later than date.
Returns
Returns the date of the first day of the week named by day that is later than date.
Example
The following code example shows how to get the date of the next Monday after April
18, 1996 (a Thursday).
Getting the Date for a Specific Day After a Specified Date
OCIDate one_day, next_day;
/* Add code here to set one_day to be '18-APR-96' */
OCIDateNextDay(err, &one_day, "MONDAY", strlen("MONDAY"), &next_day);
OCIDateNextDay() returns "22-APR-96".

This function returns an error if an invalid date or day is passed to it.
Related Topics
•

OCIDateGetDate()
Gets the year, month, and day stored in an Oracle date.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.12 OCIDateSetDate()
Set the values in an Oracle date.
Purpose
Set the values in an Oracle date.
Syntax
void OCIDateSetDate ( OCIDate
sb2
ub1
ub1

*date,
year,
month,
day );

Parameters
date (OUT)
Oracle date whose time data is set.
year (IN)
Year value to be set.
month (IN)
Month value to be set.
day (IN)
Day value to be set.
Comments
None.
Related Topics
•

OCIDateGetDate()
Gets the year, month, and day stored in an Oracle date.

28.3.13 OCIDateSetTime()
Sets the time information in an Oracle date.
Purpose
Sets the time information in an Oracle date.
Syntax
void OCIDateSetTime ( OCIDate
ub1
ub1
ub1

*date,
hour,
min,
sec );

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Parameters
date (OUT)
Oracle date whose time data is set.
hour (IN)
Hour value to be set.
min (IN)
Minute value to be set.
sec (IN)
Second value to be set.
Comments
None.
Related Topics
•

OCIDateGetTime()
Gets the time stored in an Oracle date.

28.3.14 OCIDateSysDate()
Gets the current system date and time of the client.
Purpose
Gets the current system date and time of the client.
Syntax
sword OCIDateSysDate ( OCIError
OCIDate

*err,
*sys_date );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sys_date (OUT)
Current system date and time of the client.
Comments
None.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.15 OCIDateTimeAssign()
Performs a datetime assignment.
Purpose
Performs a datetime assignment.
Syntax
sword OCIDateTimeAssign ( void
OCIError
const OCIDateTime
OCIDateTime

*hndl,
*err,
*from,
*to );

Parameters
hndl (IN)
The OCI user session handle or environment handle. If a user session handle is
passed, the conversion occurs in the session's NLS_LANGUAGE and the session's
NLS_CALENDAR; otherwise, the default is used.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
from (IN)
Source, right-hand side (rhs) datetime to be assigned.
to (OUT)
Target, left-hand side (lhs) of assignment.
Comments
This function performs an assignment from the from datetime to the to datetime for any
of the datetime types listed in the description of the type parameter.
The type of the output is the same as that of the input.
Returns
OCI_SUCCESS; or OCI_ERROR.

Related Topics
•

OCIDateTimeCheck()
Checks if the given date is valid.

•

OCIDateTimeConstruct()
Constructs a datetime descriptor.

28.3.16 OCIDateTimeCheck()
Checks if the given date is valid.
Purpose
Checks if the given date is valid.

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Syntax
sword OCIDateTimeCheck ( void
OCIError
const OCIDateTime
ub4

*hndl,
*err,
*date,
*valid );

Parameters
hndl (IN)
The OCI user session handle or environment handle. If a user session handle is
passed, the conversion occurs in the session's NLS_LANGUAGE and the session's
NLS_CALENDAR, otherwise, the default is used.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
The date to be checked.
valid (OUT)
Returns zero for a valid date; otherwise, it returns the logical operator OR combination
of all the error bits specified in Table 28-7.
Table 28-7

Error Bits Returned by the valid Parameter for OCIDateTimeCheck()

Macro Name

Bit
Number

Error

OCI_DT_INVALID_DAY

0x1

Bad day

OCI_DT_DAY_BELOW_VALID

0x2

Bad day low/high bit (1=low)

OCI_DT_INVALID_MONTH

0x4

Bad month

OCI_DT_MONTH_BELOW_VALID

0x8

Bad month low/high bit (1=low)

OCI_DT_INVALID_YEAR

0x10

Bad year

OCI_DT_YEAR_BELOW_VALID

0x20

Bad year low/high bit (1=low)

OCI_DT_INVALID_HOUR

0x40

Bad hour

OCI_DT_HOUR_BELOW_VALID

0x80

Bad hour low/high bit (1=low)

OCI_DT_INVALID_MINUTE

0x100

Bad minute

OCI_DT_MINUTE_BELOW_VALID

0x200

Bad minute low/high bit (1=low)

OCI_DT_INVALID_SECOND

0x400

Bad second

OCI_DT_SECOND_BELOW_VALID

0x800

Bad second low/high bit (1=low)

OCI_DT_DAY_MISSING_FROM_1582

0x1000

Day is one of those missing from 1582

OCI_DT_YEAR_ZERO

0x2000

Year may not equal zero

OCI_DT_INVALID_TIMEZONE

0x4000

Bad time zone

OCI_DT_INVALID_FORMAT

0x8000

Bad date format input

So, for example, if the date passed in was 2/0/1990 25:61:10 in (month/day/year
hours:minutes:seconds format), the error returned is:

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OCI_DT_INVALID_DAY | OCI_DT_DAY_BELOW_VALID |
OCI_DT_INVALID_HOUR | OCI_DT_INVALID_MINUTE.

Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; OCI_ERROR, if date or valid is a
NULL pointer.

Related Topics
•

OCIDateTimeAssign()
Performs a datetime assignment.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.17 OCIDateTimeCompare()
Compares two datetime values.
Purpose
Compares two datetime values.
Syntax
sword OCIDateTimeCompare ( void
OCIError
const OCIDateTime
const OCIDateTime
sword

*hndl,
*err,
*date1,
*date2,
*result );

Parameters
hndl (IN/OUT)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date1, date2 (IN)
Dates to be compared.
result (OUT)
Comparison result as listed in Table 28-8.
Table 28-8 Comparison Results Returned by the result Parameter for
OCIDateTimeCompare()
Comparison Result

Output in result Parameter

date1 < date2

-1

date1 = date2

0

date1 > date2

1

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Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; OCI_ERROR, if an invalid date is
used or if the input date arguments are not of mutually comparable types.

Related Topics
•

OCIDateTimeConstruct()
Constructs a datetime descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.18 OCIDateTimeConstruct()
Constructs a datetime descriptor.
Purpose
Constructs a datetime descriptor.
Syntax
sword OCIDateTimeConstruct ( void
OCIError
OCIDateTime
sb2
ub1
ub1
ub1
ub1
ub1
ub4
OraText
size_t

*hndl,
*err,
*datetime,
year,
month,
day,
hour,
min,
sec,
fsec,
*timezone,
timezone_length );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to an OCIDateTime descriptor.
year (IN)
Year value.
month (IN)
Month value.
day (IN)
Day value.

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hour (IN)
Hour value.
min (IN)
Minute value.
sec (IN)
Second value.
fsec (IN)
Fractional second value.
timezone (IN)
Time zone string. A string representation of time zone displacement is the difference
(in hours and minutes) between local time and UTC (Coordinated Universal Time—
formerly Greenwich Mean Time) in the format "[+|-][HH:MM]". For example, "-08:00".
timezone_length (IN)
Length of the time zone string.
Comments
The type of the datetime is the type of the OCIDateTime descriptor. Only the relevant
fields based on the type are used. For types with a time zone, the date and time fields
are assumed to be in the local time of the specified time zone.
If the time zone is not specified, then the session default time zone is assumed.
Returns
OCI_SUCCESS; or OCI_ERROR, if datetime is not valid.

Related Topics
•

OCIDateTimeAssign()
Performs a datetime assignment.

•

OCIDateTimeConvert()
Converts one datetime type to another.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.19 OCIDateTimeConvert()
Converts one datetime type to another.
Purpose
Converts one datetime type to another.
Syntax
sword OCIDateTimeConvert ( void
*hndl,
OCIError
*err,
OCIDateTime *indate,
OCIDateTime *outdate );

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Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
indate (IN)
A pointer to the input date.
outdate (OUT)
A pointer to the output datetime.
Comments
This function converts one datetime type to another. The result type is the type of the
outdate descriptor. The session default time zone (ORA_SDTZ) is used when converting a

datetime without a time zone to one with a time zone.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE if err is NULL; or OCI_ERROR, if the conversion is not
possible with the given input values.

Related Topics
•

OCIDateTimeCheck()
Checks if the given date is valid.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.20 OCIDateTimeFromArray()
Converts an array containing a date to an OCIDateTime descriptor.
Purpose
Converts an array containing a date to an OCIDateTime descriptor.
Syntax
sword OCIDateTimeFromArray ( void
OCIError
const ub1
ub4
ub1
OCIDateTime
const OCIInterval
ub1

*hndl,
*err,
*inarray,
*len
type,
*datetime,
*reftz,
fsprec );

Parameters
hndl (IN)
The OCI user session handle or environment handle.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inarray(IN)
Array of ub1, containing the date.
len (IN)
Length of inarray.
type (IN)
Type of the resulting datetime. The array is converted to the specific SQLT type.
datetime (OUT)
Pointer to an OCIDateTime descriptor.
reftz (IN)
Descriptor for OCIInterval used as a reference when converting a SQLT_TIMESTAMP_LTZ
type.
fsprec (IN)
Fractional second precision of the resulting datetime.
Returns
OCI_SUCCESS; or OCI_ERROR if type is invalid.

Related Topics
•

OCIDateTimeFromText()
Converts the given string to an Oracle datetime type in the OCIDateTime descriptor,
according to the specified format.

•

OCIDateTimeToArray()
Converts an OCIDateTime descriptor to an array.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.21 OCIDateTimeFromText()
Converts the given string to an Oracle datetime type in the OCIDateTime descriptor,
according to the specified format.
Purpose
Converts the given string to an Oracle datetime type in the OCIDateTime descriptor,
according to the specified format.
Syntax
sword OCIDateTimeFromText ( void
OCIError
const OraText
size_t
const OraText
ub1
const OraText

*hndl,
*err,
*date_str,
dstr_length,
*fmt,
fmt_length,
*lang_name,

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size_t
OCIDateTime

lang_length,
*datetime );

Parameters
hndl (IN)
The OCI user session handle or environment handle. If a user session handle is
passed, the conversion occurs in the session's NLS_LANGUAGE and the session's
NLS_CALENDAR; otherwise, the default is used.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date_str (IN)
The input string to be converted to an Oracle datetime.
dstr_length (IN)
The size of the input string. If the length is –1, then date_str is treated as a NULLterminated string.
fmt (IN)
The conversion format. If fmt is a NULL pointer, then the string is expected to be in the
default format for the datetime type.
fmt_length (IN)
The length of the fmt parameter.
lang_name (IN)
Specifies the language in which the names and abbreviations of months and days are
specified. The default language of the session is used if lang_name is NULL (lang_name =
(text *)0).
lang_length (IN)
The length of the lang_name parameter.
datetime (OUT)
The given string converted to a date.
Comments
See the description of the TO_DATE conversion function in the Oracle Database SQL
Language Reference for a description of the format argument.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE if err is NULL; or OCI_ERROR, if any of the following is

true:
•

An invalid format is used.

•

An unknown language is used.

•

An invalid input string is used.

Related Topics
•

OCIDateTimeToText()
Converts the given date to a string according to the specified format.

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•

OCIDateTimeFromArray()
Converts an array containing a date to an OCIDateTime descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.22 OCIDateTimeGetDate()
Gets the date (year, month, day) portion of a datetime value.
Purpose
Gets the date (year, month, day) portion of a datetime value.
Syntax
sword OCIDateTimeGetDate ( void
OCIError
const OCIDateTime
sb2
ub1
ub1

*hndl,
*err,
*datetime,
*year,
*month,
*day );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to an OCIDateTime descriptor from which date information is retrieved.
year (OUT)
month (OUT)
day (OUT)
The retrieved year, month, and day values.
Comments
This function gets the date (year, month, day) portion of a datetime value.
Returns
OCI_SUCCESS or OCI_ERROR.

Related Topics
•

OCIDateTimeGetTime()
Gets the time (hour, min, second, fractional second) of a datetime value.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.23 OCIDateTimeGetTime()
Gets the time (hour, min, second, fractional second) of a datetime value.
Purpose
Gets the time (hour, min, second, fractional second) of a datetime value.
Syntax
sword OCIDateTimeGetTime ( void
OCIError
OCIDateTime
ub1
ub1
ub1
ub4

*hndl,
*err,
*datetime,
*hour,
*min,
*sec,
*fsec );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to an OCIDateTime descriptor from which time information is retrieved.
hour (OUT)
The retrieved hour value.
min (OUT)
The retrieved minute value.
sec (OUT)
The retrieved second value.
fsec (OUT)
The retrieved fractional second value.
Comments
This function gets the time portion (hour, min, second, fractional second) from a given
datetime value.
This function returns an error if the given datetime does not contain time information.
Returns
OCI_SUCCESS; or OCI_ERROR, if datetime does not contain time (SQLT_DATE).

Related Topics
•

OCIDateTimeGetDate()
Gets the date (year, month, day) portion of a datetime value.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.24 OCIDateTimeGetTimeZoneName()
Gets the time zone name portion of a datetime value.
Purpose
Gets the time zone name portion of a datetime value.
Syntax
sword OCIDateTimeGetTimeZoneName ( void
OCIError
const OCIDateTime
ub1
ub4

*hndl,
*err,
*datetime,
*buf,
*buflen, );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to an OCIDateTime descriptor.
buf (OUT)
Buffer to store the retrieved time zone name.
buflen (IN/OUT)
The size of the buffer (IN). The size of the name field (OUT)
Comments
This function gets the time portion (hour, min, second, fractional second) from a given
datetime value.
This function returns an error if the given datetime does not contain time information.
Returns
OCI_SUCCESS; or OCI_ERROR, if datetime does not contain a time zone (SQLT_DATE,
SQLT_TIMESTAMP).

Related Topics
•

OCIDateTimeGetDate()
Gets the date (year, month, day) portion of a datetime value.

•

OCIDateTimeGetTimeZoneOffset()
Gets the time zone (hour, minute) portion of a datetime value.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.25 OCIDateTimeGetTimeZoneOffset()
Gets the time zone (hour, minute) portion of a datetime value.
Purpose
Gets the time zone (hour, minute) portion of a datetime value.
Syntax
sword OCIDateTimeGetTimeZoneOffset ( void
OCIError
const OCIDateTime
sb1
sb1

*hndl,
*err,
*datetime,
*hour,
*min, );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to an OCIDateTime descriptor.
hour (OUT)
The retrieved time zone hour value.
min (OUT)
The retrieved time zone minute value.
Comments
This function gets the time zone hour and the time zone minute portion from a given
datetime value.
This function returns an error if the given datetime does not contain time information.
Returns
OCI_SUCCESS; or OCI_ERROR, if datetime does not contain a time zone (SQLT_DATE,
SQLT_TIMESTAMP).

Related Topics
•

OCIDateTimeGetDate()
Gets the date (year, month, day) portion of a datetime value.

•

OCIDateTimeGetTimeZoneName()
Gets the time zone name portion of a datetime value.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.26 OCIDateTimeIntervalAdd()
Adds an interval to a datetime to produce a resulting datetime.
Purpose
Adds an interval to a datetime to produce a resulting datetime.
Syntax
sword OCIDateTimeIntervalAdd ( void
OCIError
OCIDateTime
OCIInterval
OCIDateTime

*hndl,
*err,
*datetime,
*inter,
*outdatetime );

Parameters
hndl (IN)
The user session or environment handle. If a session handle is passed, the addition
occurs in the session default calendar.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to the input datetime.
inter (IN)
Pointer to the input interval.
outdatetime (OUT)
Pointer to the output datetime. The output datetime is of same type as the input
datetime.
Returns
OCI_SUCCESS, if the function completes successfully; OCI_INVALID_HANDLE, if err is a NULL
pointer; or OCI_ERROR, if the resulting date is before Jan 1, -4713 or is after Dec 31,
9999.

Related Topics
•

OCIDateTimeIntervalSub()
Subtracts an interval from a datetime and stores the result in a datetime.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.27 OCIDateTimeIntervalSub()
Subtracts an interval from a datetime and stores the result in a datetime.
Purpose
Subtracts an interval from a datetime and stores the result in a datetime.

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Syntax
sword OCIDateTimeIntervalSub ( void
OCIError
OCIDateTime
OCIInterval
OCIDateTime

*hndl,
*err,
*datetime,
*inter,
*outdatetime );

Parameters
hndl (IN)
The user session or environment handle. If a session handle is passed, the
subtraction occurs in the session default calendar. The interval is assumed to be in
the session calendar.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to the input datetime value.
inter (IN)
Pointer to the input interval.
outdatetime (OUT)
Pointer to the output datetime. The output datetime is of same type as the input
datetime.
Returns
OCI_SUCCESS, if the function completes successfully; OCI_INVALID_HANDLE, if err is a NULL
pointer; or OCI_ERROR, if the resulting date is before Jan 1, -4713 or is after Dec 31,
9999.

Related Topics
•

OCIDateTimeIntervalAdd()
Adds an interval to a datetime to produce a resulting datetime.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.28 OCIDateTimeSubtract()
Takes two datetimes as input and stores their difference in an interval.
Purpose
Takes two datetimes as input and stores their difference in an interval.
Syntax
sword OCIDateTimeSubtract ( void
OCIError
OCIDateTime
OCIDateTime
OCIInterval

*hndl,
*err,
*indate1,
*indate2,
*inter );

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Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
indate1 (IN)
Pointer to the subtrahend (number to be subtracted).
indate2 (IN)
Pointer to the minuend (number to be subtracted from).
inter (OUT)
Pointer to the output interval.
Returns
OCI_SUCCESS, if the function completes successfully; OCI_INVALID_HANDLE if err is NULL
pointer; or OCI_ERROR, if the input datetimes are not of comparable types.

Related Topics
•

OCIDateTimeCompare()
Compares two datetime values.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.29 OCIDateTimeSysTimeStamp()
Gets the system current date and time as a time stamp with time zone.
Purpose
Gets the system current date and time as a time stamp with time zone.
Syntax
sword OCIDateTimeSysTimeStamp ( void
OCIError
OCIDateTime

*hndl,
*err,
*sys_date );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sys_date (OUT)
Pointer to the output time stamp.

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Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIDateSysDate()
Gets the current system date and time of the client.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.30 OCIDateTimeToArray()
Converts an OCIDateTime descriptor to an array.
Purpose
Converts an OCIDateTime descriptor to an array.
Syntax
sword OCIDateTimeToArray ( void
OCIError
const OCIDateTime
const OCIInterval
ub1
ub4
ub1

*hndl,
*err,
*datetime,
*reftz,
*outarray,
*len
fsprec );

Parameters
hndl (IN)
The OCI user session handle or environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
datetime (IN)
Pointer to an OCIDateTime descriptor.
reftz (IN)
Descriptor for the OCIInterval used as a reference when converting the
SQL_TIMESTAMP_LTZ type.
outarray(OUT)
Array of bytes containing the date.
len (OUT)
Length of outarray.
fsprec (IN)
Fractional second precision in the array.
Comments
The array is allocated by OCI and its length is returned.

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Returns
OCI_SUCCESS; or OCI_ERROR, if datetime is invalid.

Related Topics
•

OCIDateTimeToText()
Converts the given date to a string according to the specified format.

•

OCIDateTimeFromArray()
Converts an array containing a date to an OCIDateTime descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.31 OCIDateTimeToText()
Converts the given date to a string according to the specified format.
Purpose
Converts the given date to a string according to the specified format.
Syntax
sword OCIDateTimeToText ( void
OCIError
const OCIDateTime
const OraText
ub1
ub1
const OraText
size_t
ub4
OraText

*hndl,
*err,
*date,
*fmt,
fmt_length,
fsprec,
*lang_name,
lang_length,
*buf_size,
*buf );

Parameters
hndl (IN)
The OCI user session handle or environment handle. If a user session handle is
passed, the conversion occurs in the session's NLS_LANGUAGE and the session's
NLS_CALENDAR; otherwise, the default is used.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
Oracle datetime value to be converted.
fmt (IN)
The conversion format. If it is a NULL string pointer, (text*)0, then the date is
converted to a character string in the default format for that type.
fmt_length (IN)
The length of the fmt parameter.

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fsprec (IN)
Specifies the precision in which the fractional seconds value is returned.
lang_name (IN)
Specifies the language in which the names and abbreviations of months and days are
returned. The default language of the session is used if lang_name is NULL (lang_name =
(OraText *)0).
lang_length (IN)
The length of the lang_name parameter.
buf_size (IN/OUT)
The size of the buf buffer (IN).
The size of the resulting string after the conversion (OUT).
buf (OUT)
The buffer into which the converted string is placed.
Comments
See the description of the TO_DATE conversion function in the Oracle Database SQL
Language Reference for a description of format and multilingual arguments. The
converted NULL-terminated date string is stored in the buffer buf.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is NULL; or OCI_ERROR, if any of the following
statements is true:

•

The buffer is too small.

•

An invalid format is used.

•

An unknown language is used.

•

There is an overflow error.

Related Topics
•

OCIDateTimeFromText()
Converts the given string to an Oracle datetime type in the OCIDateTime descriptor,
according to the specified format.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.32 OCIDateToText()
Converts a date type to a character string.
Purpose
Converts a date type to a character string.
Syntax
sword OCIDateToText ( OCIError
const OCIDate
const OraText
ub1

*err,
*date,
*fmt,
fmt_length,

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const OraText
ub4
ub4
OraText

*lang_name,
lang_length,
*buf_size,
*buf );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date (IN)
Oracle date to be converted.
fmt (IN)
Conversion format. If NULL, (text *)0, then the date is converted to a character string
in the default date format, DD-MON-YY.
fmt_length (IN)
Length of the fmt parameter.
lang_name (IN)
Specifies the language in which names and abbreviations of months and days are
returned; the default language of the session is used if lang_name is NULL ((text *)0).
lang_length (IN)
Length of the lang_name parameter.
buf_size (IN/OUT)
Size of the buffer (IN). Size of the resulting string is returned with this parameter
(OUT).
buf (OUT)
Buffer into which the converted string is placed.
Comments
Converts the given date to a string according to the specified format. The converted
NULL-terminated date string is stored in buf.
See the TO_DATE conversion function described in the Oracle Database SQL Language
Reference for a description of format and multilingual arguments.
Returns
This function returns an error if the buffer is too small, or if the function is passed an
invalid format or unknown language. Overflow also causes an error. For example,
converting a value of 10 into format '9' causes an error.
Related Topics
•

OCIDateFromText()
Converts a character string to a date type according to the specified format.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.3.33 OCIDateZoneToZone()
Converts a date from one time zone to another.
Purpose
Converts a date from one time zone to another.
Syntax
sword OCIDateZoneToZone ( OCIError
const OCIDate
const OraText
ub4
const OraText
ub4
OCIDate

*err,
*date1,
*zon1,
zon1_length,
*zon2,
zon2_length,
*date2 );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
date1 (IN)
Date to convert.
zon1 (IN)
Zone of the input date.
zon1_length (IN)
Length in bytes of zon1.
zon2 (IN)
Zone to be converted to.
zon2_length (IN)
Length in bytes of zon2.
date2 (OUT)
Converted date (in zon2).
Comments
Converts a given date date1 in time zone zon1 to a date date2 in time zone zon2. Works
only with North American time zones.
For a list of valid zone strings, see the description of the NEW_TIME function in the Oracle
Database SQL Language Reference. Examples of valid zone strings include:
•

AST, Atlantic Standard Time

•

ADT, Atlantic Daylight Time

•

BST, Bering Standard Time

•

BDT, Bering Daylight Time

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Returns
This function returns an error if an invalid date or time zone is passed to it.
Related Topics
•

OCIDateCheck()
Checks if the given date is valid.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.34 OCIIntervalAdd()
Adds two intervals to produce a resulting interval.
Purpose
Adds two intervals to produce a resulting interval.
Syntax
sword OCIIntervalAdd ( void
OCIError
OCIInterval
OCIInterval
OCIInterval

*hndl,
*err,
*addend1,
*addend2,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
addend1 (IN)
Interval to be added.
addend2 (IN)
Interval to be added.
result (OUT)
The resulting interval (addend1 + addend2).
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if any of the
following statements is true:

•

The two input intervals are not mutually comparable.

•

The resulting year is greater than SB4MAXVAL.

•

The resulting year is less than SB4MINVAL.

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Related Topics
•

OCIIntervalSubtract()
Subtracts two intervals and stores the result in an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.35 OCIIntervalAssign()
Copies one interval to another.
Purpose
Copies one interval to another.
Syntax
void OCIIntervalAssign ( void
OCIError
const OCIInterval
OCIInterval

*hndl,
*err,
*inpinter,
*outinter );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inpinter (IN)
Input interval.
outinter (OUT)
Output interval.
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalCompare()
Compares two intervals.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.36 OCIIntervalCheck()
Checks the validity of an interval.
Purpose
Checks the validity of an interval.

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Syntax
sword OCIIntervalCheck ( void
OCIError
const OCIInterval
ub4

*hndl,
*err,
*interval,
*valid );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
interval (IN)
Interval to be checked.
valid (OUT)
Returns zero if the interval is valid; otherwise, it returns the logical operator OR
combination of the codes specified in Table 28-9.
Table 28-9

Error Bits Returned by the valid Parameter for OCIIntervalCheck()

Macro Name

Bit
Number

Error

OCI_INTER_INVALID_DAY

0x1

Bad day

OCI_INTER_DAY_BELOW_VALID

0x2

Bad day low/high bit (1=low)

OCI_INTER_INVALID_MONTH

0x4

Bad month

OCI_INTER_MONTH_BELOW_VALID

0x8

Bad month low/high bit (1=low)

OCI_INTER_INVALID_YEAR

0x10

Bad year

OCI_INTER_YEAR_BELOW_VALID

0x20

Bad year low/high bit (1=low)

OCI_INTER_INVALID_HOUR

0x40

Bad hour

OCI_INTER_HOUR_BELOW_VALID

0x80

Bad hour low/high bit (1=low)

OCI_INTER_INVALID_MINUTE

0x100

Bad minute

OCI_INTER_MINUTE_BELOW_VALID

0x200

Bad minute low/high bit (1=low)

OCI_INTER_INVALID_SECOND

0x400

Bad second

OCI_INTER_SECOND_BELOW_VALID

0x800

Bad second low/high bit (1=low)

OCI_INTER_INVALID_FRACSEC

0x1000

Bad fractional second

OCI_INTER_FRACSEC_BELOW_VALID

0x2000

Bad fractional second low/high bit
(1=low)

Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, on error.

Related Topics
•

OCIIntervalCompare()
Compares two intervals.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.37 OCIIntervalCompare()
Compares two intervals.
Purpose
Compares two intervals.
Syntax
sword OCIIntervalCompare (void
OCIError
OCIInterval
OCIInterval
sword

*hndl,
*err,
*inter1,
*inter2,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inter1 (IN)
Interval to be compared.
inter2 (IN)
Interval to be compared.
result (OUT)
Comparison result as specified in Table 28-10.
Table 28-10 Comparison Results Returned by the result Parameter for
OCIIntervalCompare()
Comparison Result

Output in result Parameter

inter1 < inter2

-1

inter1 = inter2

0

inter1 > inter2

1

Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if the input values
are not mutually comparable.

Related Topics
•

OCIIntervalAssign()
Copies one interval to another.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.38 OCIIntervalDivide()
Divides an interval by an Oracle NUMBER to produce an interval.
Purpose
Divides an interval by an Oracle NUMBER to produce an interval.
Syntax
sword OCIIntervalDivide ( void
OCIError
OCIInterval
OCINumber
OCIInterval

*hndl,
*err,
*dividend,
*divisor,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
dividend (IN)
Interval to be divided.
divisor (IN)
Oracle NUMBER dividing dividend.
result (OUT)
The resulting interval ( dividend / divisor).
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalMultiply()
Multiplies an interval by an Oracle NUMBER to produce an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.39 OCIIntervalFromNumber()
Converts an Oracle NUMBER to an interval.
Purpose
Converts an Oracle NUMBER to an interval.

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Syntax
sword OCIIntervalFromNumber ( void
OCIError
OCIInterval
OCINumber

*hndl,
*err,
*interval,
*number );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
interval (OUT)
Interval result.
number (IN)
Oracle NUMBER to be converted (in years for YEAR TO MONTH intervals and in days
for DAY TO SECOND intervals).
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalToNumber()
Converts an interval to an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.40 OCIIntervalFromText()
When given an interval string, returns the interval represented by the string. The type
of the interval is the type of the result descriptor.
Purpose
When given an interval string, returns the interval represented by the string. The type
of the interval is the type of the result descriptor.
Syntax
sword OCIIntervalFromText ( void
OCIError
const OraText
size_t
OCIInterval

*hndl,
*err,
*inpstring,
str_len,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inpstring (IN)
Input string.
str_len (IN)
Length of the input string.
result (OUT)
Resultant interval.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if any of the
following statements is true:

•

There are too many fields in the literal string.

•

The year is out of range (–4713 to 9999).

•

The month is out of range (1 to 12).

•

The day of month is out of range (1 to 28...31).

•

The hour is out of range (0 to 23).

•

The hour is out of range (0 to 11).

•

The minutes are out of range (0 to 59).

•

The seconds in the minute are out of range (0 to 59).

•

The seconds in the day are out of range (0 to 86399).

•

The interval is invalid.

Related Topics
•

OCIIntervalToText()
When given an interval, produces a string representing the interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.41 OCIIntervalFromTZ()
Returns an OCI_DTYPE_INTERVAL_DS of data type OCIInterval with the region ID set (if the
region is specified in the input string) and the current absolute offset, or an absolute
offset with the region ID set to 0.
Purpose
Returns an OCI_DTYPE_INTERVAL_DS of data type OCIInterval with the region ID set (if the
region is specified in the input string) and the current absolute offset, or an absolute
offset with the region ID set to 0.
Syntax
sword OCIIntervalFromTZ ( void
*hndl,
OCIError
*err,
const oratext *inpstring,

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size_t
OCIInterval

str_len,
*result ) ;

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inpstring (IN)
Pointer to the input string.
str_len (IN)
Length of inpstring.
result (OUT)
Output interval.
Returns
OCI_SUCCESS, on success; OCI_INVALID_HANDLE, if err is NULL; or OCI_ERROR, if there is a
bad interval type or there are time zone errors.

Comments
The input string must be of the form [+/-]TZH:TZM or 'TZR [TZD]'
Related Topics
•

OCIIntervalFromText()
When given an interval string, returns the interval represented by the string. The
type of the interval is the type of the result descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.42 OCIIntervalGetDaySecond()
Gets values of day, hour, minute, and second from an interval.
Purpose
Gets values of day, hour, minute, and second from an interval.
Syntax
sword OCIIntervalGetDaySecond (void
OCIError
sb4
sb4
sb4
sb4
sb4
const OCIInterval

*hndl,
*err,
*dy,
*hr,
*mm,
*ss,
*fsec,
*interval );

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Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
dy (OUT)
Number of days.
hr (OUT)
Number of hours.
mm (OUT)
Number of minutes.
ss (OUT)
Number of seconds.
fsec (OUT)
Number of nano seconds.
interval (IN)
The input interval.
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalSetDaySecond()
Sets day, hour, minute, and second in an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.43 OCIIntervalGetYearMonth()
Gets year and month from an interval.
Purpose
Gets year and month from an interval.
Syntax
sword OCIIntervalGetYearMonth ( void
OCIError
sb4
sb4
const OCIInterval

*hndl,
*err,
*yr,
*mnth,
*interval );

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Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
yr (OUT)
Year value.
mnth (OUT)
Month value.
interval (IN)
The input interval.
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalSetYearMonth()
Sets year and month in an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.44 OCIIntervalMultiply()
Multiplies an interval by an Oracle NUMBER to produce an interval.
Purpose
Multiplies an interval by an Oracle NUMBER to produce an interval.
Syntax
sword OCIIntervalMultiply ( void
OCIError
const OCIInterval
OCINumber
OCIInterval

*hndl,
*err,
*inter,
*nfactor,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inter (IN)
Interval to be multiplied.

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nfactor (IN)
Oracle NUMBER to be multiplied.
result (OUT)
The resulting interval (inter * nfactor).
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if any of the
following statements is true:

•

The resulting year is greater than SB4MAXVAL.

•

The resulting year is less than SB4MINVAL.

Related Topics
•

OCIIntervalDivide()
Divides an interval by an Oracle NUMBER to produce an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.45 OCIIntervalSetDaySecond()
Sets day, hour, minute, and second in an interval.
Purpose
Sets day, hour, minute, and second in an interval.
Syntax
sword OCIIntervalSetDaySecond ( void
OCIError
sb4
sb4
sb4
sb4
sb4
OCIInterval

*hndl,
*err,
dy,
hr,
mm,
ss,
fsec,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
dy (IN)
Number of days.
hr (IN)
Number of hours.
mm (IN)
Number of minutes.

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ss (IN)
Number of seconds.
fsec (IN)
Number of nano seconds.
result (OUT)
The resulting interval.
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalGetDaySecond()
Gets values of day, hour, minute, and second from an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.46 OCIIntervalSetYearMonth()
Sets year and month in an interval.
Purpose
Sets year and month in an interval.
Syntax
sword OCIIntervalSetYearMonth ( void
OCIError
sb4
sb4
OCIInterval

*hndl,
*err,
yr,
mnth,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
yr (IN)
Year value.
mnth (IN)
Month value.
result (OUT)
The resulting interval.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if any of the
following statements is true:

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•

The resulting year is greater than SB4MAXVAL.

•

The resulting year is less than SB4MINVAL.

Related Topics
•

OCIIntervalGetYearMonth()
Gets year and month from an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.47 OCIIntervalSubtract()
Subtracts two intervals and stores the result in an interval.
Purpose
Subtracts two intervals and stores the result in an interval.
Syntax
sword OCIIntervalSubtract ( void
OCIError
OCIInterval
OCIInterval
OCIInterval

*hndl,
*err,
*minuend,
*subtrahend,
*result );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
minuend (IN)
The interval to be subtracted from.
subtrahend (IN)
The interval subtracted from minuend.
result (OUT)
The resulting interval (minuend - subtrahend).
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if any of the
following statements is true:

•

The resulting year is greater than SB4MAXVAL.

•

The resulting year is less than SB4MINVAL.

•

The two input intervals are not mutually comparable.

Related Topics
•

OCIIntervalAdd()
Adds two intervals to produce a resulting interval.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.48 OCIIntervalToNumber()
Converts an interval to an Oracle NUMBER.
Purpose
Converts an interval to an Oracle NUMBER.
Syntax
sword OCIIntervalToNumber ( void
OCIError
OCIInterval
OCINumber

*hndl,
*err,
*interval,
*number );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
interval (IN)
Interval to be converted.
number (OUT)
Oracle NUMBER result (in years for YEARMONTH interval and in days for DAYSECOND).
Comments
Fractional portions of the date (for instance, minutes and seconds if the unit chosen is
hours) are included in the Oracle NUMBER produced. Excess precision is truncated.
Returns
OCI_SUCCESS; or OCI_INVALID_HANDLE, if err is a NULL pointer.

Related Topics
•

OCIIntervalFromNumber()
Converts an Oracle NUMBER to an interval.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.3.49 OCIIntervalToText()
When given an interval, produces a string representing the interval.
Purpose
When given an interval, produces a string representing the interval.

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Syntax
sword OCIIntervalToText ( void
OCIError
const OCIInterval
ub1
ub1
OraText
size_t
size_t

*hndl,
*err,
*interval,
lfprec,
fsprec,
*buffer,
buflen,
*resultlen );

Parameters
hndl (IN)
The OCI user session handle or the environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
interval (IN)
Interval to be converted.
lfprec (IN)
Leading field precision. (The number of digits used to represent the leading field.)
fsprec (IN)
Fractional second precision of the interval (the number of digits used to represent the
fractional seconds).
buffer (OUT)
Buffer to hold the result.
buflen (IN)
The length of buffer.
resultlen (OUT)
The length of the result placed into buffer.
Comments
The interval literal is output as 'year' or '[year-]month' for INTERVAL YEAR TO MONTH
intervals and as 'seconds' or 'minutes[:seconds]' or 'hours[:minutes[:seconds]]' or
'days[ hours[:minutes[:seconds]]]' for INTERVAL DAY TO SECOND intervals (where optional
fields are surrounded by brackets).
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE, if err is a NULL pointer; or OCI_ERROR, if the buffer is not
large enough to hold the result.

Related Topics
•

OCIIntervalFromText()
When given an interval string, returns the interval represented by the string. The
type of the interval is the type of the result descriptor.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4 OCI NUMBER Functions
Lists and describes the OCI NUMBER functions.
Table 28-11 describes the OCI NUMBER functions that are described in this section.

See Also:
OCINumber Examples

Table 28-11

NUMBER Functions

Function

Purpose

OCINumberAbs()

Compute the absolute value

OCINumberAdd()

Add a NUMBER to a NUMBER

OCINumberArcCos()

Compute the arc cosine

OCINumberArcSin()

Compute the arc sine

OCINumberArcTan()

Compute the arc tangent

OCINumberArcTan2()

Compute the arc tangent given two
arguments for NUMBER

OCINumberAssign()

Assign one NUMBER to another

OCINumberCeil()

Compute the ceiling of NUMBER

OCINumberCmp()

Compare one NUMBER with another NUMBER

OCINumberCos()

Compute the cosine

OCINumberDec()

Decrement a NUMBER

OCINumberDiv()

Divide a NUMBER by a NUMBER

OCINumberExp()

Raise e to the specified Oracle NUMBER
power

OCINumberFloor()

Compute the floor value of a NUMBER

OCINumberFromInt()

Convert an integer to an Oracle NUMBER

OCINumberFromReal()

Convert a real type to an Oracle NUMBER

OCINumberFromText()

Convert a string to an Oracle NUMBER

OCINumberHypCos()

Compute the hyperbolic cosine

OCINumberHypSin()

Compute the hyperbolic sine

OCINumberHypTan()

Compute the hyperbolic tangent

OCINumberInc()

Increment an Oracle NUMBER

OCINumberIntPower()

Raise a given base to an integer power

OCINumberIsInt()

Test if a NUMBER is an integer

OCINumberIsZero()

Test if a NUMBER is zero

OCINumberLn()

Compute the natural logarithm

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Table 28-11

(Cont.) NUMBER Functions

Function

Purpose

OCINumberLog()

Compute the logarithm to an arbitrary base

OCINumberMod()

Gets the modulus (remainder) of the division
of two Oracle NUMBERs

OCINumberMul()

Multiply one Oracle NUMBER by another
Oracle NUMBER

OCINumberNeg()

Negates an Oracle NUMBER

OCINumberPower()

Raises a given base to a given exponent

OCINumberPrec()

Round a NUMBER to a specified number of
decimal places

OCINumberRound()

Round an Oracle NUMBER to a specified
decimal place

OCINumberSetPi()

Initialize a NUMBER to pi

OCINumberSetZero()

Initialize a NUMBER to zero

OCINumberShift()

Multiply by 10, shifting a specified number of
decimal places

OCINumberSign()

Obtain the sign of an Oracle NUMBER

OCINumberSin()

Compute the sine

OCINumberSqrt()

Compute the square root of a NUMBER

OCINumberSub()

Subtract a NUMBER from a NUMBER

OCINumberTan()

Compute the tangent

OCINumberToInt()

Convert an Oracle NUMBER to an integer

OCINumberToReal()

Convert an Oracle NUMBER to a real type

OCINumberToRealArray()

Convert an array of NUMBER to a real array.

OCINumberToText()

Convert an Oracle NUMBER to a string

OCINumberTrunc()

Truncate an Oracle NUMBER at a specified
decimal place

28.4.1 OCINumberAbs()
Computes the absolute value of an Oracle NUMBER.
Purpose
Computes the absolute value of an Oracle NUMBER.
Syntax
sword OCINumberAbs ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Input NUMBER.
result (OUT)
The absolute value of the input NUMBER.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.2 OCINumberAdd()
Adds a NUMBER to another NUMBER.
Purpose
Adds a NUMBER to another NUMBER.
Syntax
sword OCINumberAdd ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1, number2 (IN)
The first NUMBER to be added to the second NUMBER.
result (OUT)
Result of adding number1 to number2.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberSub()
Subtracts one Oracle NUMBER from another Oracle NUMBER.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.3 OCINumberArcCos()
Takes the arc cosine in radians of an Oracle NUMBER.
Purpose
Takes the arc cosine in radians of an Oracle NUMBER.
Syntax
sword OCINumberArcCos ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the arc cosine.
result (OUT)
Result of the arc cosine in radians.
Returns
This function returns an error if any of the NUMBER arguments is NULL, if number is less
than –1, or if number is greater than 1.
Related Topics
•

OCINumberCos()
Computes the cosine in radians of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.4 OCINumberArcSin()
Takes the arc sine in radians of an Oracle NUMBER.
Purpose
Takes the arc sine in radians of an Oracle NUMBER.
Syntax
sword OCINumberArcSin ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the arc sine.
result (OUT)
Result of the arc sine in radians.
Returns
This function returns an error if any of the NUMBER arguments is NULL, if number is less
than –1, or if number is greater than 1.
Related Topics
•

OCINumberSin()
Computes the sine in radians of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.5 OCINumberArcTan()
Takes the arc tangent in radians of an Oracle NUMBER.
Purpose
Takes the arc tangent in radians of an Oracle NUMBER.
Syntax
sword OCINumberArcTan ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the arc tangent.
result (OUT)
Result of the arc tangent in radians.
Returns
This function returns an error if any of the NUMBER arguments is NULL.

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Related Topics
•

OCINumberTan()
Computes the tangent in radians of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.6 OCINumberArcTan2()
Takes the arc tangent given two arguments for Oracle NUMBER.
Purpose
Takes the arc tangent given two arguments for Oracle NUMBER.
Syntax
sword OCINumberArcTan2 ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1 (IN)
Argument 1 of the arc tangent.
number2 (IN)
Argument 2 of the arc tangent.
result (OUT)
Result of the arc tangent in radians.
Returns
This function returns an error if any of the NUMBER arguments is NULL or if number2 equals
0.
Related Topics
•

OCINumberTan()
Computes the tangent in radians of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.7 OCINumberAssign()
Assigns one Oracle NUMBER to another Oracle NUMBER.
Purpose
Assigns one Oracle NUMBER to another Oracle NUMBER.

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Syntax
sword OCINumberAssign ( OCIError
const OCINumber
OCINumber

*err,
*from,
*to );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
from (IN)
NUMBER to be assigned.

to (OUT)
NUMBER copied into.
Comments
Assigns the NUMBER identified by from to the NUMBER identified by to.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberCmp()
Compares one Oracle NUMBER with another Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.8 OCINumberCeil()
Computes the ceiling value of an Oracle NUMBER.
Purpose
Computes the ceiling value of an Oracle NUMBER.
Syntax
sword OCINumberCeil ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Input NUMBER.

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result (OUT)
Output that contains the ceiling value of the input NUMBER.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberFloor()
Computes the floor (round down) value of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.9 OCINumberCmp()
Compares one Oracle NUMBER with another Oracle NUMBER.
Purpose
Compares one Oracle NUMBER with another Oracle NUMBER.
Syntax
sword OCINumberCmp ( OCIError
const OCINumber
const OCINumber
sword

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1, number2 (IN)
The first NUMBER to compare with the second NUMBER.
result (OUT)
Comparison result as specified in Table 28-12.
Table 28-12 Comparison Results Returned by the result Parameter for
OCINumberCmp()
Comparison Result

Output in result Parameter

number1 < number2

negative

number1 = number2

0

number1 > number2

positive

Returns
This function returns an error if any of the NUMBER arguments is NULL.

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Related Topics
•

OCINumberAssign()
Assigns one Oracle NUMBER to another Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.10 OCINumberCos()
Computes the cosine in radians of an Oracle NUMBER.
Purpose
Computes the cosine in radians of an Oracle NUMBER.
Syntax
sword OCINumberCos ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the cosine in radians.
result (OUT)
Result of the cosine.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberArcCos()
Takes the arc cosine in radians of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.11 OCINumberDec()
12.1.0.2, added a short description.
Purpose
Decrements an Oracle NUMBER in place.
Syntax
sword OCINumberDec ( OCIError *err,
OCINumber *number );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN/OUT)
A positive Oracle NUMBER to be decremented.
Comments
Decrements an Oracle NUMBER in place. It is assumed that the input is an integer
between 0 and 100^21-2. If the input is too large, it is treated as 0; the result is an
Oracle NUMBER 1. If the input is not a positive integer, the result is unpredictable.
Returns
This function returns an error if the input NUMBER is NULL.
Related Topics
•

OCINumberInc()
Increments an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.12 OCINumberDiv()
Divides one Oracle NUMBER by another Oracle NUMBER.
Purpose
Divides one Oracle NUMBER by another Oracle NUMBER.
Syntax
sword OCINumberDiv ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1 (IN)
Pointer to the numerator.
number2 (IN)
Pointer to the denominator.
result (OUT)
Division result.

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Comments
Divides number1 by number2 and returns the result in result.
Returns
This function returns an error if any of the following statements is true:
•

Any of the NUMBER arguments is NULL.

•

There is an underflow error.

•

There is a divide-by-zero error.

Related Topics
•

OCINumberMul()
Multiplies one Oracle NUMBER by another Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.13 OCINumberExp()
Raises e to the specified Oracle NUMBER power.
Purpose
Raises e to the specified Oracle NUMBER power.
Syntax
sword OCINumberExp ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
This function raises e to this Oracle NUMBER power.
result (OUT)
Output of exponentiation.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberLn()
Takes the natural logarithm (base e) of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.4.14 OCINumberFloor()
Computes the floor (round down) value of an Oracle NUMBER.
Purpose
Computes the floor (round down) value of an Oracle NUMBER.
Syntax
sword OCINumberFloor ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Input NUMBER.
result (OUT)
The floor (round down) value of the input NUMBER.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberCeil()
Computes the ceiling value of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.15 OCINumberFromInt()
Converts an integer to an Oracle NUMBER.
Purpose
Converts an integer to an Oracle NUMBER.
Syntax
sword OCINumberFromInt ( OCIError
const void
uword
uword
OCINumber

*err,
*inum,
inum_length,
inum_s_flag,
*number );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
inum (IN)
Pointer to the integer to convert.
inum_length (IN)
Size of the integer.
inum_s_flag (IN)
Flag that designates the sign of the integer, as follows:
•

OCI_NUMBER_UNSIGNED - Unsigned values

•

OCI_NUMBER_SIGNED - Signed values

number (OUT)
Given integer converted to Oracle NUMBER.
Comments
This is a native type conversion function. It converts any Oracle standard systemnative integer type, such as ub4 or sb2, to an Oracle NUMBER.
Returns
This function returns an error if the number is too big to fit into an Oracle NUMBER, if
number or inum is NULL, or if an invalid sign flag value is passed in inum_s_flag.
Related Topics
•

OCINumberToInt()
Converts an Oracle NUMBER type to integer.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.16 OCINumberFromReal()
Converts a real (floating-point) type to an Oracle NUMBER.
Purpose
Converts a real (floating-point) type to an Oracle NUMBER.
Syntax
sword OCINumberFromReal ( OCIError
const void
uword
OCINumber

*err,
*rnum,
rnum_length,
*number );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
rnum (IN)
Pointer to the floating-point number to convert.
rnum_length (IN)
The size of the desired result, which equals sizeof({float | double | long double}).
number (OUT)
Given float converted to Oracle NUMBER.
Comments
This is a native type conversion function. It converts a system-native floating-point type
to an Oracle NUMBER.
Returns
This function returns an error if number or rnum is NULL, or if rnum_length equals zero.
Related Topics
•

OCINumberFromText()
Converts a character string to an Oracle NUMBER.

28.4.17 OCINumberFromText()
Converts a character string to an Oracle NUMBER.
Purpose
Converts a character string to an Oracle NUMBER.
Syntax
sword OCINumberFromText ( OCIError
const OraText
ub4
const OraText
ub4
const OraText
ub4
OCINumber

*err,
*str,
str_length,
*fmt,
fmt_length,
*nls_params,
nls_p_length,
*number );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
str (IN)
Input string to convert to Oracle NUMBER.

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str_length (IN)
Size of the input string.
fmt (IN)
Conversion format.
fmt_length (IN)
Length of the fmt parameter.
nls_params (IN)
Globalization support format specification. If it is the NULL string (""), then the default
parameters for the session are used.
nls_p_length (IN)
Length of the nls_params parameter.
number (OUT)
Given string converted to NUMBER.
Comments
Converts the given string to a NUMBER according to the specified format. See the
TO_NUMBER conversion function described in the Oracle Database SQL Language
Reference for a description of format and multilingual parameters.
Returns
This function returns an error if there is an invalid format, an invalid multibyte format,
or an invalid input string, if number or str is NULL, or if str_length is zero.

28.4.18 OCINumberHypCos()
Computes the hyperbolic cosine of an Oracle NUMBER.
Purpose
Computes the hyperbolic cosine of an Oracle NUMBER.
Syntax
sword OCINumberHypCos ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the cosine hyperbolic.
result (OUT)
Result of the cosine hyperbolic.

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Returns
This function returns an error if either of the number arguments is NULL.

Note:
An Oracle NUMBER overflow causes an unpredictable result value.

Related Topics
•

OCINumberHypSin()
Computes the hyperbolic sine of an Oracle NUMBER.

•

OCINumberHypTan()
Computes the hyperbolic tangent of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.19 OCINumberHypSin()
Computes the hyperbolic sine of an Oracle NUMBER.
Purpose
Computes the hyperbolic sine of an Oracle NUMBER.
Syntax
sword OCINumberHypSin ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the sine hyperbolic.
result (OUT)
Result of the sine hyperbolic.
Returns
This function returns an error if either of the NUMBER arguments is NULL.

Note:
An Oracle NUMBER overflow causes an unpredictable result value.

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Related Topics
•

OCINumberHypCos()
Computes the hyperbolic cosine of an Oracle NUMBER.

•

OCINumberHypTan()
Computes the hyperbolic tangent of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.20 OCINumberHypTan()
Computes the hyperbolic tangent of an Oracle NUMBER.
Purpose
Computes the hyperbolic tangent of an Oracle NUMBER.
Syntax
sword OCINumberHypTan ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the tangent hyperbolic.
result (OUT)
Result of the tangent hyperbolic.
Returns
This function returns an error if either of the NUMBER arguments is NULL.

Note:
An Oracle NUMBER overflow causes an unpredictable result value.

Related Topics
•

OCINumberHypCos()
Computes the hyperbolic cosine of an Oracle NUMBER.

•

OCINumberHypSin()
Computes the hyperbolic sine of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.4.21 OCINumberInc()
Increments an Oracle NUMBER.
Purpose
Increments an Oracle NUMBER.
Syntax
sword OCINumberInc ( OCIError *err,
OCINumber *number );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN/OUT)
A positive Oracle NUMBER to be incremented.
Comments
Increments an Oracle NUMBER in place. It is assumed that the input is an integer
between 0 and 100^21-2. If the input is too large, it is treated as 0 - the result is an
Oracle NUMBER 1. If the input is not a positive integer, the result is unpredictable.
Returns
This function returns an error if the input NUMBER is NULL.
Related Topics
•

OCINumberDec()
12.1.0.2, added a short description.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.22 OCINumberIntPower()
Raises a given base to a given integer power.
Purpose
Raises a given base to a given integer power.
Syntax
sword OCINumberIntPower ( OCIError
const OCINumber
const sword
OCINumber

*err,
*base,
exp,
*result );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
base (IN)
Base of the exponentiation.
exp (IN)
Exponent to which the base is raised.
result (OUT)
Output of exponentiation.
Returns
This function returns an error if either of the NUMBER arguments is NULL.
Related Topics
•

OCINumberPower()
Raises a given base to a given exponent.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.23 OCINumberIsInt()
Tests if an OCINumber is an integer.
Purpose
Tests if an OCINumber is an integer.
Syntax
sword OCINumberIsInt ( OCIError
*err,
const OCINumber *number,
boolean
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
NUMBER to be tested.
result (OUT)
Set to TRUE if integer value; otherwise, FALSE
Returns
This function returns an error if number or result is NULL.

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Related Topics
•

OCINumberRound()
Rounds an Oracle NUMBER to a specified decimal place.

•

OCINumberTrunc()
Truncates an Oracle NUMBER at a specified decimal place.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.24 OCINumberIsZero()
Tests if the given NUMBER equals zero.
Purpose
Tests if the given NUMBER equals zero.
Syntax
sword OCINumberIsZero ( OCIError
const OCINumber
boolean

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
NUMBER to compare.
result (OUT)
Set to TRUE if equal to zero; otherwise, set to FALSE.
Returns
This function returns an error if the NUMBER argument is NULL.
Related Topics
•

OCINumberSetZero()
Initializes an Oracle NUMBER to zero.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.25 OCINumberLn()
Takes the natural logarithm (base e) of an Oracle NUMBER.
Purpose
Takes the natural logarithm (base e) of an Oracle NUMBER.

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Syntax
sword OCINumberLn ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Logarithm of this NUMBER is computed.
result (OUT)
Logarithm result.
Returns
This function returns an error if either of the NUMBER arguments is NULL, or if number is
less than or equal to zero.
Related Topics
•

OCINumberExp()
Raises e to the specified Oracle NUMBER power.

•

OCINumberLog()
Takes the logarithm, to any base, of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.26 OCINumberLog()
Takes the logarithm, to any base, of an Oracle NUMBER.
Purpose
Takes the logarithm, to any base, of an Oracle NUMBER.
Syntax
sword OCINumberLog ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*base,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
base (IN)
Base of the logarithm.

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number (IN)
Operand.
result (OUT)
Logarithm result.
Returns
This function returns an error if:
•

Any of the NUMBER arguments is NULL

•

The value of number <= 0

•

The value of base <= 0

Related Topics
•

OCINumberLn()
Takes the natural logarithm (base e) of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.27 OCINumberMod()
Gets the modulus (remainder) of the division of two Oracle NUMBERs.
Purpose
Gets the modulus (remainder) of the division of two Oracle NUMBERs.
Syntax
sword OCINumberMod ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1 (IN)
Pointer to the numerator.
number2 (IN)
Pointer to the denominator.
result (OUT)
Remainder of the result.
Returns
This function returns an error if number1 or number2 is NULL, or if there is a divide-by-zero
error.

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Related Topics
•

OCINumberDiv()
Divides one Oracle NUMBER by another Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.28 OCINumberMul()
Multiplies one Oracle NUMBER by another Oracle NUMBER.
Purpose
Multiplies one Oracle NUMBER by another Oracle NUMBER.
Syntax
sword OCINumberMul ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1 (IN)
NUMBER to multiply.

number2 (IN)
NUMBER to multiply.

result (OUT)
Multiplication result.
Comments
Multiplies number1 with number2 and returns the result in result.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberDiv()
Divides one Oracle NUMBER by another Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.4.29 OCINumberNeg()
Negates an Oracle NUMBER.
Purpose
Negates an Oracle NUMBER.
Syntax
sword OCINumberNeg ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
NUMBER to negate.
result (OUT)
Contains negated value of number.
Returns
This function returns an error if either of the NUMBER arguments is NULL.
Related Topics
•

OCINumberAbs()
Computes the absolute value of an Oracle NUMBER.

•

OCINumberSign()
Gets sign of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.30 OCINumberPower()
Raises a given base to a given exponent.
Purpose
Raises a given base to a given exponent.
Syntax
sword OCINumberPower ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*base,
*number,
*result );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
base (IN)
Base of the exponentiation.
number (IN)
Exponent to which the base is to be raised.
result (OUT)
Output of exponentiation.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberExp()
Raises e to the specified Oracle NUMBER power.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.31 OCINumberPrec()
Rounds an OCINumber to a specified number of decimal digits.
Purpose
Rounds an OCINumber to a specified number of decimal digits.
Syntax
sword OCINumberPrec ( OCIError
const OCINumber
eword
OCINumber

*err,
*number,
nDigs,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
The number for which to set precision.
nDigs (IN)
The number of decimal digits desired in the result.
result (OUT)
The result.

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Comments
Performs a floating-point round with respect to the number of digits.
Returns
This function returns an error any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberRound()
Rounds an Oracle NUMBER to a specified decimal place.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.32 OCINumberRound()
Rounds an Oracle NUMBER to a specified decimal place.
Purpose
Rounds an Oracle NUMBER to a specified decimal place.
Syntax
sword OCINumberRound ( OCIError
const OCINumber
sword
OCINumber

*err,
*number,
decplace,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
NUMBER to round.
decplace (IN)
Number of decimal digits to the right of the decimal point to round to. Negative values
are allowed.
result (OUT)
Output of rounding.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberTrunc()
Truncates an Oracle NUMBER at a specified decimal place.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.4.33 OCINumberSetPi()
Sets an OCINumber to pi.
Purpose
Sets an OCINumber to pi.
Syntax
void OCINumberSetPi ( OCIError *err,
OCINumber *num );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
num (OUT)
NUMBER set to the value of pi.

Comments
Initializes the given NUMBER to the value of pi.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.34 OCINumberSetZero()
Initializes an Oracle NUMBER to zero.
Purpose
Initializes an Oracle NUMBER to zero.
Syntax
void OCINumberSetZero ( OCIError
OCINumber

*err
*num );

Parameters
err (IN)
A valid OCI error handle. This function does not check for errors because the function
never produces an error.
num (IN/OUT)
Oracle NUMBER to initialize to zero value.
Comments
None.

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Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.35 OCINumberShift()
Multiplies a NUMBER by a power of 10 by shifting it a specified number of decimal places.
Purpose
Multiplies a NUMBER by a power of 10 by shifting it a specified number of decimal places.
Syntax
sword OCINumberShift ( OCIError
const OCINumber
const sword
OCINumber

*err,
*number,
nDig,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Oracle NUMBER to be shifted.
nDig (IN)
Number of decimal places to shift.
result (OUT)
Shift result.
Comments
Multiplies number by 10^nDig and sets product to the result.
Returns
This function returns an error if the input number is NULL.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.36 OCINumberSign()
Gets sign of an Oracle NUMBER.
Purpose
Gets sign of an Oracle NUMBER.

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Syntax
sword OCINumberSign ( OCIError
const OCINumber
sword

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Oracle NUMBER whose sign is returned.
result (OUT)
Table 28-13 lists the possible return values.
Table 28-13

Values of result

Value of number

Output in result Parameter

number < 0

-1

number == 0

0

number > 0

1

Returns
This function returns an error if number or result is NULL.
Related Topics
•

OCINumberAbs()
Computes the absolute value of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.37 OCINumberSin()
Computes the sine in radians of an Oracle NUMBER.
Purpose
Computes the sine in radians of an Oracle NUMBER.
Syntax
sword OCINumberSin ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the sine in radians.
result (OUT)
Result of the sine.
Returns
This function returns an error if either of the number arguments is NULL.
Related Topics
•

OCINumberArcSin()
Takes the arc sine in radians of an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.38 OCINumberSqrt()
Computes the square root of an Oracle NUMBER.
Purpose
Computes the square root of an Oracle NUMBER.
Syntax
sword OCINumberSqrt ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Input NUMBER.
result (OUT)
Output that contains the square root of the input NUMBER.
Returns
This function returns an error if number is NULL or number is negative.
Related Topics
•

OCINumberPower()
Raises a given base to a given exponent.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.39 OCINumberSub()
Subtracts one Oracle NUMBER from another Oracle NUMBER.
Purpose
Subtracts one Oracle NUMBER from another Oracle NUMBER.
Syntax
sword OCINumberSub ( OCIError
const OCINumber
const OCINumber
OCINumber

*err,
*number1,
*number2,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number1, number2 (IN)
This function subtracts number2 from number1.
result (OUT)
Subtraction result.
Comments
Subtracts number2 from number1 and returns the result in result.
Returns
This function returns an error if any of the number arguments is NULL.
Related Topics
•

OCINumberAdd()
Adds a NUMBER to another NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.40 OCINumberTan()
Computes the tangent in radians of an Oracle NUMBER.
Purpose
Computes the tangent in radians of an Oracle NUMBER.
Syntax
sword OCINumberTan ( OCIError
const OCINumber
OCINumber

*err,
*number,
*result );

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Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Argument of the tangent in radians.
result (OUT)
Result of the tangent.
Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberArcTan()
Takes the arc tangent in radians of an Oracle NUMBER.

•

OCINumberArcTan2()
Takes the arc tangent given two arguments for Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.41 OCINumberToInt()
Converts an Oracle NUMBER type to integer.
Purpose
Converts an Oracle NUMBER type to integer.
Syntax
sword OCINumberToInt ( OCIError
const OCINumber
uword
uword
void

*err,
*number,
rsl_length,
rsl_flag,
*rsl );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Oracle NUMBER to convert.
rsl_length (IN)
Size of the desired result.
rsl_flag (IN)
Flag that designates the sign of the output, as follows:

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•

OCI_NUMBER_UNSIGNED - Unsigned values

•

OCI_NUMBER_SIGNED - Signed values

rsl (OUT)
Pointer to space for the result.
Comments
This is a native type conversion function. It converts the given Oracle NUMBER into an
integer of the form xbn, such as ub2, ub4, or sb2.
Returns
This function returns an error if number or rsl is NULL, if number is too big (overflow) or
too small (underflow), or if an invalid sign flag value is passed in rsl_flag.
Related Topics
•

OCINumberFromInt()
Converts an integer to an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.42 OCINumberToReal()
Converts an Oracle NUMBER type to a real type.
Purpose
Converts an Oracle NUMBER type to a real type.
Syntax
sword OCINumberToReal ( OCIError
const OCINumber
uword
void

*err,
*number,
rsl_length,
*rsl );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Oracle NUMBER to convert.
rsl_length (IN)
The size of the desired result, which equals sizeof({ float | double | long double}).
rsl (OUT)
Pointer to space for storing the result.
Comments
This is a native type conversion function. It converts an Oracle NUMBER into a systemnative real type. This function only converts NUMBERs up to LDBL_DIG, DBL_DIG, or

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FLT_DIG digits of precision and removes trailing zeros. These constants are defined in
float.h.

You must pass a valid OCINumber to this function. Otherwise, the result is undefined.
Related Topics
•

OCINumberFromReal()
Converts a real (floating-point) type to an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.43 OCINumberToRealArray()
Converts an array of NUMBER to an array of real type.
Purpose
Converts an array of NUMBER to an array of real type.
Syntax
sword OCINumberToRealArray ( OCIError
const OCINumber
uword
uword
void

*err,
**number,
elems,
rsl_length,
*rsl );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Pointer to array of NUMBER to be converted.
elems (IN)
Maximum number of NUMBER pointers.
rsl_length (IN)
The size of the desired result, that is, sizeof({ float | double | long double }).
rsl (OUT)
Pointer to array of space for storing the result.
Comments
Native type conversion function that converts an Oracle NUMBER into a system-native
real type. This function only converts numbers up to LDBL_DIG, DBL_DIG, or FLT_DIG
digits of precision and removes trailing zeroes. The constants are defined in the
float.h header file.
You must pass a valid OCINumber to this function. Otherwise, the result is undefined.

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Returns
OCI_SUCCESS, if the function completes successfully; OCI_INVALID_HANDLE, if err is NULL; or
OCI_ERROR, if number or rsl is NULL or rsl_length is 0.

Related Topics
•

OCINumberToReal()
Converts an Oracle NUMBER type to a real type.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.44 OCINumberToText()
Converts an Oracle NUMBER to a character string according to a specified format.
Purpose
Converts an Oracle NUMBER to a character string according to a specified format.
Syntax
sword OCINumberToText ( OCIError
const OCINumber
const OraText
ub4
const OraText
ub4
ub4
OraText

*err,
*number,
*fmt,
fmt_length,
*nls_params,
nls_p_length,
*buf_size,
*buf );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Oracle NUMBER to convert.
fmt (IN)
Conversion format.
fmt_length (IN)
Length of the fmt parameter.
nls_params (IN)
Globalization support format specification. If it is a NULL string ((text *)0 ), then the
default parameters for the session is used.
nls_p_length (IN)
Length of the nls_params parameter.
buf_size (IN)
Size of the buffer.

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buf (OUT)
Buffer into which the converted string is placed.
Comments
See the TO_NUMBER conversion function described in the Oracle Database SQL
Language Referencefor a description of format and globalization support parameters.
The converted number string is stored in buf, up to a maximum of buf_size bytes.
Returns
This function returns an error if:
•

The value of number or buf is NULL

•

The buffer is too small

•

An invalid format or invalid multibyte format is passed

•

A number to text translation for given format causes an overflow

Related Topics
•

OCINumberFromText()
Converts a character string to an Oracle NUMBER.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.4.45 OCINumberTrunc()
Truncates an Oracle NUMBER at a specified decimal place.
Purpose
Truncates an Oracle NUMBER at a specified decimal place.
Syntax
sword OCINumberTrunc ( OCIError
const OCINumber
sword
OCINumber

*err,
*number,
decplace,
*result );

Parameters
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
number (IN)
Input NUMBER.
decplace (IN)
Number of decimal digits to the right of the decimal point at which to truncate.
Negative values are allowed.
result (OUT)
Output of truncation.

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Returns
This function returns an error if any of the NUMBER arguments is NULL.
Related Topics
•

OCINumberRound()
Rounds an Oracle NUMBER to a specified decimal place.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.5 OCI Raw Functions
Lists and describes the OCI raw functions.
Table 28-14 describes the OCI raw functions that are described in this section.
Table 28-14

Raw Functions

Function

Purpose

OCIRawAllocSize()

Get allocated size of raw memory in bytes

OCIRawAssignBytes()

Assign raw bytes to raw

OCIRawAssignRaw()

Assign raw to raw

OCIRawPtr()

Get raw data pointer

OCIRawResize()

Resize memory of variable-length raw

OCIRawSize()

Get raw size

28.5.1 OCIRawAllocSize()
Gets the allocated size of raw memory in bytes.
Purpose
Gets the allocated size of raw memory in bytes.
Syntax
sword OCIRawAllocSize ( OCIEnv
OCIError
const OCIRaw
ub4

*env,
*err,
*raw,
*allocsize );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
raw (IN)
Raw data whose allocated size in bytes is returned. This must be a non-NULL pointer.
allocsize (OUT)
The allocated size of raw memory in bytes that is returned.
Comments
The allocated size is greater than or equal to the actual raw size.
Related Topics
•

OCIRawResize()
Resizes the memory of a given variable-length raw.

•

OCIRawSize()
Returns the size of a given raw in bytes.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.5.2 OCIRawAssignBytes()
Assigns raw bytes of type ub1* to Oracle OCIRaw* data type.
Purpose
Assigns raw bytes of type ub1* to Oracle OCIRaw* data type.
Syntax
sword OCIRawAssignBytes ( OCIEnv
OCIError
const ub1
ub4
OCIRaw

*env,
*err,
*rhs,
rhs_len,
**lhs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
rhs (IN)
Right-hand side (source) of the assignment, of data type ub1.
rhs_len (IN)
Length of the rhs raw bytes.
lhs (IN/OUT)
Left-hand side (target) of the assignment OCIRaw data.
Comments
Assigns rhs raw bytes to lhs raw data type. The lhs raw may be resized depending
upon the size of the rhs. The raw bytes assigned are of type ub1.
Related Topics
•

OCIRawAssignRaw()
Assigns one Oracle RAW data type to another Oracle RAW data type.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.5.3 OCIRawAssignRaw()
Assigns one Oracle RAW data type to another Oracle RAW data type.
Purpose
Assigns one Oracle RAW data type to another Oracle RAW data type.
Syntax
sword OCIRawAssignRaw ( OCIEnv
OCIError
const OCIRaw
OCIRaw

*env,
*err,
*rhs,
**lhs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
rhs (IN)
Right-hand side (rhs) (source) of the assignment; OCIRaw data.
lhs (IN/OUT)
Left-hand side (lhs) (target) of the assignment; OCIRaw data.
Comments
Assigns rhs OCIRaw to lhs OCIRaw. The lhs OCIRaw may be resized depending upon the
size of the rhs.
Related Topics
•

OCIRawAssignBytes()
Assigns raw bytes of type ub1* to Oracle OCIRaw* data type.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.5.4 OCIRawPtr()
Gets the pointer to raw data.
Purpose
Gets the pointer to raw data.
Syntax
ub1 *OCIRawPtr ( OCIEnv
const OCIRaw

*env,
*raw );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
raw (IN)
Pointer to the data of a given raw.
Comments
None.

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Related Topics
•

OCIRawAssignBytes()
Assigns raw bytes of type ub1* to Oracle OCIRaw* data type.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.5.5 OCIRawResize()
Resizes the memory of a given variable-length raw.
Purpose
Resizes the memory of a given variable-length raw.
Syntax
sword OCIRawResize ( OCIEnv
OCIError
ub2
OCIRaw

*env,
*err,
new_size,
**raw );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
new_size (IN)
New size of the raw data in bytes.
raw (IN)
Variable-length raw pointer; the raw is resized to new_size.
Comments
This function resizes the memory of the given variable-length raw in the object cache.
The previous contents of the raw are not preserved. This function may allocate the raw
in a new memory region in which case the original memory occupied by the given raw
is freed. If the input raw is NULL (raw == NULL), then this function allocates memory for
the raw data.

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If the new_size is 0, then this function frees the memory occupied by raw, and a NULL
pointer value is returned.
Related Topics
•

OCIRawAllocSize()
Gets the allocated size of raw memory in bytes.

•

OCIRawSize()
Returns the size of a given raw in bytes.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.5.6 OCIRawSize()
Returns the size of a given raw in bytes.
Purpose
Returns the size of a given raw in bytes.
Syntax
ub4 OCIRawSize ( OCIEnv
const OCIRaw

*env,
*raw );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
raw (IN/OUT)
Raw whose size is returned.
Comments
None.
Related Topics
•

OCIRawAllocSize()
Gets the allocated size of raw memory in bytes.

•

OCIRawResize()
Resizes the memory of a given variable-length raw.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6 OCI REF Functions
Lists and describes the OCI Reference (REF) functions.
Table 28-15 describes the OCI Reference (REF) functions that are described in this
section.
Table 28-15

Ref Functions

Function

Purpose

OCIRefAssign()

Assign one REF to another

OCIRefClear()

Clear or nullify a REF

OCIRefFromHex()

Convert hexadecimal string to REF

OCIRefHexSize()

Return size of hexadecimal representation of REF

OCIRefIsEqual()

Compare two REFs for equality

OCIRefIsNull()

Test if a REF is NULL

OCIRefToHex()

Convert REF to hexadecimal string

28.6.1 OCIRefAssign()
Assigns one REF to another, such that both reference the same object.
Purpose
Assigns one REF to another, such that both reference the same object.
Syntax
sword OCIRefAssign ( OCIEnv
OCIError
const OCIRef
OCIRef

*env,
*err,
*source,
**target );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
source (IN)
REF to copy from.
target (IN/OUT)
REF to copy to.

Comments
Copies source REF to target REF; both then reference the same object. If the target REF
pointer is NULL (*target == NULL), then OCIRefAssign() allocates memory for the target
REF in the OCI object cache before the copy operation.
Related Topics
•

OCIRefIsEqual()
Compares two REFs to determine if they are equal.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6.2 OCIRefClear()
Clears or NULLifies a given REF.
Purpose
Clears or NULLifies a given REF.
Syntax
void OCIRefClear ( OCIEnv
OCIRef

*env,
*ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
ref (IN/OUT)
REF to clear.

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Comments
A REF is considered to be a NULL REF if it no longer points to an object. Logically, a NULL
REF is a dangling REF.
Note that a NULL REF is still a valid SQL value and is not SQL NULL. It can be used as a
valid non-NULL constant REF value for a NOT NULL column or attribute of a row in a table.
If a NULL pointer value is passed as a REF, then this function is nonoperational.
Related Topics
•

OCIRefIsNull()
Tests if a REF is NULL.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6.3 OCIRefFromHex()
Converts the given hexadecimal string into a REF.
Purpose
Converts the given hexadecimal string into a REF.
Syntax
sword OCIRefFromHex ( OCIEnv
OCIError
const OCISvcCtx
const OraText
ub4
OCIRef

*env,
*err,
*svc,
*hex,
length,
**ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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svc (IN)
The OCI service context handle, if the resulting ref is initialized with this service
context.
hex (IN)
Hexadecimal text string, previously output by OCIRefToHex(), to convert into a REF.
length (IN)
Length of the hexadecimal text string.
ref (IN/OUT)
The REF into which the hexadecimal string is converted. If *ref is NULL on input, then
space for the REF is allocated in the object cache; otherwise, the memory occupied by
the given REF is reused.
Comments
This function ensures that the resulting REF is well formed. It does not ensure that the
object pointed to by the resulting REF exists.
Related Topics
•

OCIRefToHex()
Converts a REF to a hexadecimal string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6.4 OCIRefHexSize()
Returns the size of the hexadecimal representation of a REF.
Purpose
Returns the size of the hexadecimal representation of a REF.
Syntax
ub4 OCIRefHexSize ( OCIEnv
const OCIRef

*env,
*ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.

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ref (IN)
REF whose size in hexadecimal representation in bytes is returned.

Comments
Returns the size of the buffer in bytes required for the hexadecimal representation of
the ref. A buffer of at least this size must be passed to the ref-to-hex (OCIRefToHex())
conversion function.
Returns
The size of the hexadecimal representation of the REF.
Related Topics
•

OCIRefFromHex()
Converts the given hexadecimal string into a REF.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6.5 OCIRefIsEqual()
Compares two REFs to determine if they are equal.
Purpose
Compares two REFs to determine if they are equal.
Syntax
boolean OCIRefIsEqual ( OCIEnv
const OCIRef
const OCIRef

*env,
*x,
*y );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
x (IN)
REF to compare.
y (IN)
REF to compare.

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Comments
Two REFs are equal if and only if they are both referencing the same object, whether
persistent or transient.

Note:
Two NULL REFs are considered not equal by this function.

Returns
TRUE, if the two REFs are equal.
FALSE, if the two REFs are not equal, or x is NULL, or y is NULL.

Related Topics
•

OCIRefAssign()
Assigns one REF to another, such that both reference the same object.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6.6 OCIRefIsNull()
Tests if a REF is NULL.
Purpose
Tests if a REF is NULL.
Syntax
boolean OCIRefIsNull ( OCIEnv
const OCIRef

*env,
*ref );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
ref (IN)
REF to test for NULL.

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Comments
A REF is NULL if and only if:
•

It is supposed to be referencing a persistent object, but the object's identifier is
NULL

•

It is supposed to be referencing a transient object, but it is currently not pointing to
an object

Note:
A REF is a dangling REF if the object that it points to does not exist.

Returns
Returns TRUE if the given REF is NULL; otherwise, it returns FALSE.
Related Topics
•

OCIRefClear()
Clears or NULLifies a given REF.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.6.7 OCIRefToHex()
Converts a REF to a hexadecimal string.
Purpose
Converts a REF to a hexadecimal string.
Syntax
sword OCIRefToHex ( OCIEnv
OCIError
const OCIRef
OraText
ub4

*env,
*err,
*ref,
*hex,
*hex_length );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
ref (IN)
REF to be converted into a hexadecimal string; if ref is a NULL REF (that is,
OCIRefIsNull(ref) == TRUE), then a zero hex_length value is returned.

hex (OUT)
Buffer that is large enough to contain the resulting hexadecimal string; the content of
the string is opaque to the caller.
hex_length (IN/OUT)
On input, specifies the size of the hex buffer; on output, specifies the actual size of the
hexadecimal string being returned in hex.
Comments
Converts the given REF into a hexadecimal string, and returns the length of the string.
The resulting string is opaque to the caller.
Returns
This function returns an error if the given buffer is not big enough to hold the resulting
string.
Related Topics
•

OCIRefFromHex()
Converts the given hexadecimal string into a REF.

•

OCIRefHexSize()
Returns the size of the hexadecimal representation of a REF.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.7 OCI String Functions
Lists and describes the OCI string functions.
Table 28-16 describes the OCI string functions that are described in this section.
Table 28-16

String Functions

Function

Purpose

OCIStringAllocSize()

Get the allocated size of string memory in
bytes

OCIStringAssign()

Assign a string to a string

OCIStringAssignText()

Assign a text string to a string

OCIStringPtr()

Get a string pointer

OCIStringResize()

Resize the string memory

OCIStringSize()

Get the string size

28.7.1 OCIStringAllocSize()
Gets the allocated size of string memory in code points (Unicode) or in bytes.
Purpose
Gets the allocated size of string memory in code points (Unicode) or in bytes.
Syntax
sword OCIStringAllocSize ( OCIEnv
OCIError
const OCIString
ub4

*env,
*err,
*vs,
*allocsize );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
vs (IN)
String whose allocated size in bytes is returned. The vs parameter must be a non-NULL
pointer.
allocsize (OUT)
The allocated size of string memory in bytes is returned.

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Comments
The allocated size is greater than or equal to the actual string size.
Related Topics
•

OCIStringResize()
Resizes the memory of a given string.

•

OCIStringSize()
Gets the size of the given string vs.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.7.2 OCIStringAssign()
Assigns one string to another string.
Purpose
Assigns one string to another string.
Syntax
sword OCIStringAssign ( OCIEnv
OCIError
const OCIString
OCIString

*env,
*err,
*rhs,
**lhs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
rhs (IN)
Right-hand side (source) of the assignment. Can be in UTF-16 format.
lhs (IN/OUT)
Left-hand side (target) of the assignment. Its buffer is in UTF-16 format if rhs is
UTF-16.

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Comments
Assigns rhs string to lhs string. The lhs string can be resized depending upon the size
of the rhs. The assigned string is NULL-terminated. The length field does not include the
extra code point or byte needed for NULL-termination.
Returns
This function returns an error if the assignment operation runs out of space.
Related Topics
•

OCIStringAssignText()
Assigns the source text string to the target string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.7.3 OCIStringAssignText()
Assigns the source text string to the target string.
Purpose
Assigns the source text string to the target string.
Syntax
sword OCIStringAssignText ( OCIEnv
OCIError
const OraText
ub4
OCIString

*env,
*err,
*rhs,
rhs_len,
**lhs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
rhs (IN)
Right-hand side (source) of the assignment, a text or UTF-16 Unicode string.

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rhs_len (IN)
Length of the rhs string in bytes.
lhs (IN/OUT)
Left-hand side (target) of the assignment. Its buffer is in Unicode if rhs is in Unicode.
Comments
Assigns rhs string to lhs string. The lhs string may be resized depending upon the size
of the rhs. The assigned string is NULL-terminated. The length field does not include the
extra byte or code point needed for NULL-termination.
Related Topics
•

OCIStringAssign()
Assigns one string to another string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.7.4 OCIStringPtr()
Gets a pointer to the text of a given string.
Purpose
Gets a pointer to the text of a given string.
Syntax
text *OCIStringPtr ( OCIEnv
const OCIString

*env,
*vs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
vs (IN)
Pointer to the OCIString object whose character string is returned. If vs is in UTF-16
format, the returned buffer is also in UTF-16 format. To determine the encoding of the
returned buffer, check the UTF-16 information in the OCIString vs itself, because it is
not guaranteed that a particular OCIString will have the same setting as env does.
Check an object OCI function that is designed to check member fields in objects.

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Comments
None.
Related Topics
•

OCIStringAssign()
Assigns one string to another string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.7.5 OCIStringResize()
Resizes the memory of a given string.
Purpose
Resizes the memory of a given string.
Syntax
sword OCIStringResize ( OCIEnv
OCIError
ub4
OCIString

*env,
*err,
new_size,
**str );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
new_size (IN)
New memory size of the string in bytes. The new_size parameter must include space
for the NULL character as the string terminator.
str (IN/OUT)
Allocated memory for the string that is freed from the OCI object cache.
Comments
This function resizes the memory of the given variable-length string in the object
cache. Contents of the string are not preserved. This function may allocate the string

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in a new memory region, in which case the original memory occupied by the given
string is freed. If str is NULL, this function allocates memory for the string. If new_size is
0, this function frees the memory occupied by str and a NULL pointer value is returned.
Related Topics
•

OCIStringAllocSize()
Gets the allocated size of string memory in code points (Unicode) or in bytes.

•

OCIStringSize()
Gets the size of the given string vs.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.7.6 OCIStringSize()
Gets the size of the given string vs.
Purpose
Gets the size of the given string vs.
Syntax
ub4 OCIStringSize ( OCIEnv
const OCIString

*env,
*vs );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
vs (IN)
String whose size is returned, in number of bytes.
Comments
The returned size does not include an extra byte for NULL termination.
Related Topics
•

OCIStringResize()
Resizes the memory of a given string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.8 OCI Table Functions
Lists and describes the OCI table functions.
Table 28-17 describes the OCI table functions that are described in this section.
Table 28-17

Table Functions

Function

Purpose

OCITableDelete()

Delete element

OCITableExists()

Test whether element exists

OCITableFirst()

Return first index of table

OCITableLast()

Return last index of table

OCITableNext()

Return next available index of table

OCITablePrev()

Return previous available index of table

OCITableSize()

Return current size of table

28.8.1 OCITableDelete()
Deletes the element at the specified index.
Purpose
Deletes the element at the specified index.
Syntax
sword OCITableDelete ( OCIEnv
OCIError
sb4
OCITable

*env,
*err,
index,
*tbl );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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index (IN)
Index of the element that must be deleted.
tbl (IN)
Table whose element is deleted.
Comments
This function returns an error if the element at the given index has already been
deleted or if the given index is not valid for the given table.

Note:
The position ordinals of the remaining elements of the table are not changed
by OCITableDelete(). The delete operation creates holes in the table.

Returns
An error is also returned if any input parameter is NULL.
Related Topics
•

OCITableExists()
Tests whether an element exists at the given index.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.8.2 OCITableExists()
Tests whether an element exists at the given index.
Purpose
Tests whether an element exists at the given index.
Syntax
sword OCITableExists ( OCIEnv
OCIError
const OCITable
sb4
boolean

*env,
*err,
*tbl,
index,
*exists );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tbl (IN)
Table in which the given index is checked.
index (IN)
Index of the element that is checked for existence.
exists (OUT)
Set to TRUE if the element at the given index exists; otherwise, it is set to FALSE.
Returns
This function returns an error if any input parameter is NULL.
Related Topics
•

OCITableDelete()
Deletes the element at the specified index.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.8.3 OCITableFirst()
Returns the index of the first existing element in a given table.
Purpose
Returns the index of the first existing element in a given table.
Syntax
sword OCITableFirst ( OCIEnv
OCIError
const OCITable
sb4

*env,
*err,
*tbl,
*index );

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Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tbl (IN)
Table to scan.
index (OUT)
First index of the element that exists in the given table that is returned.
Comments
If OCITableDelete() deletes the first five elements of a table, OCITableFirst() returns
the value 6.

See Also:
OCITableDelete() for information regarding non-data holes (deleted
elements) in tables

Returns
This function returns an error if the table is empty.
Related Topics
•

OCITableDelete()
Deletes the element at the specified index.

•

OCITableLast()
Returns the index of the last existing element of a table.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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28.8.4 OCITableLast()
Returns the index of the last existing element of a table.
Purpose
Returns the index of the last existing element of a table.
Syntax
sword OCITableLast ( OCIEnv
OCIError
const OCITable
sb4

*env,
*err,
*tbl,
*index );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tbl (IN)
Table to scan.
index (OUT)
Index of the last existing element in the table.
Comments
OCITableLast() returns the largest index numbered element in the index by integer

collection.
Returns
This function returns an error if the table is empty.
Related Topics
•

OCITableFirst()
Returns the index of the first existing element in a given table.

•

OCITableNext()
Returns the index of the next existing element of a table.

•

OCITablePrev()
Returns the index of the previous existing element of a table.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

28.8.5 OCITableNext()
Returns the index of the next existing element of a table.
Purpose
Returns the index of the next existing element of a table.
Syntax
sword OCITableNext ( OCIEnv
OCIError
sb4
const OCITable
sb4
boolean

*env,
*err,
index,
*tbl,
*next_index
*exists );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
index (IN)
Index for the starting point of the scan.
tbl (IN)
Table to scan.
next_index (OUT)
Index of the next existing element after tbl(index).
exists (OUT)
FALSE if no next index is available; otherwise, TRUE.
Returns
Returns the smallest position j, greater than index, such that exists(j) is TRUE.
Related Topics
•

OCITablePrev()
Returns the index of the previous existing element of a table.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
The description of OCITableSize() for information about the existence of nondata holes (deleted elements) in tables

28.8.6 OCITablePrev()
Returns the index of the previous existing element of a table.
Purpose
Returns the index of the previous existing element of a table.
Syntax
sword OCITablePrev ( OCIEnv
OCIError
sb4
const OCITable
sb4
boolean

*env,
*err,
index,
*tbl,
*prev_index
*exists );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
index (IN)
Index for the starting point of the scan.
tbl (IN)
Table to scan.
prev_index (OUT)
Index of the previous existing element before tbl(index).
exists (OUT)
FALSE if no previous index is available; otherwise, TRUE.

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Returns
Returns the largest position j, less than index, such that exists (j) is TRUE.
Related Topics
•

OCITableNext()
Returns the index of the next existing element of a table.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

See Also:
The description of OCITableSize() for information about the existence of nondata holes (deleted elements) in tables

28.8.7 OCITableSize()
Returns the size of the given table, not including any holes created by deleted
elements.
Purpose
Returns the size of the given table, not including any holes created by deleted
elements.
Syntax
sword OCITableSize ( OCIEnv
OCIError
const OCITable
sb4

*env,
*err,
*tbl
*size );

Parameters
env (IN/OUT)
The OCI environment handle initialized in object mode. See the descriptions of
OCIEnvCreate(), OCIEnvNlsCreate(), and OCIInitialize() (deprecated) for more
information.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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tbl (IN)
Nested table whose number of elements is returned.
size (OUT)
Current number of elements in the nested table. The count does not include deleted
elements.
Comments
The count is decremented when elements are deleted from the nested table. So this
count does not include any holes created by deleting elements. To get the count
including the holes created by the deleted elements, use OCICollSize().
The following code example shows a code fragment where an element is deleted from
a nested table.
Deleting an Element from a Nested table
OCITableSize(...);
// assume 'size' returned is equal to 5
OCITableDelete(...); // delete one element
OCITableSize(...);
// 'size' returned is equal to 4

To get the count plus the count of deleted elements, use OCICollSize(), as shown in
the following code example. Continuing the previous code example.
Getting a Count of All Elements Including Deleted Elements from a Nested Table
OCICollSize(...)
// 'size' returned is still equal to 5

Returns
This function returns an error if an error occurs during the loading of the nested table
into the object cache, or if any of the input parameters is NULL.
Related Topics
•

OCICollSize()
Gets the current size in number of elements of the given collection.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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29
OCI Cartridge Functions
This chapter presents the cartridge functions.
For code examples, see the demonstration programs included with your Oracle
Database installation. For additional information, see OCI Demonstration Programs.
This chapter contains these topics:
•

Introduction to External Procedure and Cartridge Services Functions

•

Cartridge Services — OCI External Procedures

•

Cartridge Services — Memory Services

•

Cartridge Services — Maintaining Context

•

Cartridge Services — Parameter Manager Interface

•

Cartridge Services — File I/O Interface

•

Cartridge Services — String Formatting Interface

29.1 Introduction to External Procedure and Cartridge
Services Functions
This section introduces the OCI external procedure functions.
These functions enable users of external procedures to raise errors, allocate some
memory, and get OCI context information.
Then the cartridge services functions are described.

See Also:
•

Oracle Database Development Guide for more information about using
these functions in external procedures

•

Oracle Database Data Cartridge Developer's Guide for more information
about using these functions

29.1.1 Conventions for OCI Functions
Describes conventions used in describing each function.
See the Conventions for OCI Functions for the conventions used in describing each
function. The entries for each function may also contain the following information:
•

Return Codes

•

With_Context Type

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Return Codes
Success and error return codes are defined for certain external procedure interface
functions. If a particular interface function returns OCIEXTPROC_SUCCESS or
OCIEXTPROC_ERROR, then applications must use these macros to check for return values.
•

OCIEXTPROC_SUCCESS - External Procedure Success Return Code

•

OCIEXTPROC_ERROR - External Procedure Failure Return Code

With_Context Type
The C callable interface to PL/SQL external procedures requires the with_context
parameter to be passed. The type of this structure is OCIExtProcContext, which is
opaque to the user.
The user can declare the with_context parameter in the application as follows:
OCIExtProcContext *with_context;

29.2 Cartridge Services — OCI External Procedures
Lists and describes cartridge services OCI external procedure functions.
Table 29-1 lists the OCI external procedure functions for C that are described in this
section.
Table 29-1

External Procedures Functions

Function

Purpose

OCIExtProcAllocCallMemory()

Allocate memory for the duration of the
External Procedure

OCIExtProcGetEnv()

Get the OCI environment, service context,
and error handles

OCIExtProcRaiseExcp()

Raise an Exception to PL/SQL

OCIExtProcRaiseExcpWithMsg()

Raise an exception with a message

29.2.1 OCIExtProcAllocCallMemory()
Allocates N bytes of memory for the duration of the external procedure.
Purpose
Allocates N bytes of memory for the duration of the external procedure.
Syntax
void * OCIExtProcAllocCallMemory ( OCIExtProcContext
size_t

*with_context,
amount );

Parameters
with_context (IN)
The with_context pointer that is passed to the C external procedure.

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With_Context Type — The C callable interface to PL/SQL external procedures requires
the with_context parameter to be passed. The type of this structure is
OCIExtProcContext, which is opaque to the user.
The user can declare the with_context parameter in the application as follows:
OCIExtProcContext *with_context;

amount (IN)
The number of bytes to allocate.
Comments
This call allocates amount bytes of memory for the duration of the call of the external
procedure.
Any memory allocated by this call is freed by PL/SQL upon return from the external
procedure. The application must not use any kind of free() function on memory
allocated by OCIExtProcAllocCallMemory(). Use this function to allocate memory for
function returns.
A zero return value should be treated as an error.
Returns
An untyped (opaque) pointer to the allocated memory.
Example
Using OCIExtProcAllocCallMemory() to Allocate 1024 Bytes of Memory
text *ptr = (text *)OCIExtProcAllocCallMemory(wctx, 1024)

Related Topics
•

OCIMemoryAlloc()
Allocates memory of a given size from a given duration.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.2.2 OCIExtProcGetEnv()
Gets the OCI environment, service context, and error handles.
Purpose
Gets the OCI environment, service context, and error handles.
Syntax
sword OCIExtProcGetEnv ( OCIExtProcContext
OCIEnv
OCISvcCtx
OCIError

*with_context,
**envh,
**svch,
**errh );

Parameters
with_context (IN)
The with_context pointer that is passed to the C external procedure.

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With_Context Type — The C callable interface to PL/SQL external procedures requires
the with_context parameter to be passed. The type of this structure is
OCIExtProcContext, which is opaque to the user.
The user can declare the with_context parameter in the application as follows:
OCIExtProcContext *with_context;

envh (OUT)
Pointer to a variable to store the OCI environment handle.
svch (OUT)
Pointer to a variable to store the OCI service handle.
errh (OUT)
Pointer to a variable to store the OCI error handle.
Comments
The primary purpose of this function is to allow OCI callbacks to use the database in
the same transaction. The OCI handles obtained by this function should be used in
OCI callbacks to the database. If these handles are obtained through standard OCI
calls, then these handles use a new connection to the database and cannot be used
for callbacks in the same transaction. In one external procedure you can use either
callbacks or a new connection, but not both.
Example of a call:
OCIEnv
*envh;
OCISvcCtx *svch;
OCIError *errh;
...
OCIExtProcGetEnv(ctx,&envh,&svch,&errh);

Returns
This function returns OCI_SUCCESS if the call succeeds; otherwise, it returns OCI_ERROR.
Related Topics
•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCIArrayDescriptorAlloc()
Allocates an array of descriptors.

•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

29.2.3 OCIExtProcRaiseExcp()
Raises an Exception to PL/SQL.
Purpose
Raises an Exception to PL/SQL.
Syntax
size_t OCIExtProcRaiseExcp ( OCIExtProcContext
int

*with_context,
errnum );

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Parameters
with_context (IN)
The with_context pointer that is passed to the C external procedure.
With_Context Type — The C callable interface to PL/SQL external procedures requires
the with_context parameter to be passed. The type of this structure is
OCIExtProcContext, which is opaque to the user.
The user can declare the with_context parameter in the application as follows:
OCIExtProcContext *with_context;

errnum (IN)
Oracle Database error number to signal to PL/SQL. The errnum value must be a
positive number and in the range 1 to 32767.
Comments
Calling this function signals an exception to PL/SQL. After a successful return from this
function, the external procedure must start its exit handling and return to PL/SQL.
Once an exception is signaled to PL/SQL, IN/OUT and OUT arguments, if any, are not
processed at all.
Returns
This function returns OCIEXTPROC_SUCCESS if the call succeeds. It returns
OCIEXTPROC_ERROR if the call fails.
Related Topics
•

OCIExtProcRaiseExcpWithMsg()
Raises an exception with a message.

29.2.4 OCIExtProcRaiseExcpWithMsg()
Raises an exception with a message.
Purpose
Raises an exception with a message.
Syntax
size_t OCIExtProcRaiseExcpWithMsg ( OCIExtProcContext
int
char
size_t

*with_context,
errnum,
*errmsg,
msglen );

Parameters
with_context (IN)
The with_context pointer that is passed to the C external procedure.
With_Context Type — The C callable interface to PL/SQL external procedures requires
the with_context parameter to be passed. The type of this structure is
OCIExtProcContext, which is opaque to the user.
The user can declare the with_context parameter in the application as follows:
OCIExtProcContext *with_context;

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errnum (IN)
Oracle Database error number to signal to PL/SQL. The value of errnum must be a
positive number and in the range 1 to 32767
errmsg (IN)
The error message associated with errnum.
msglen (IN)
The length of the error message. Pass zero if errmsg is a NULL-terminated string.
Comments
This call raises an exception to PL/SQL. In addition, it substitutes the following error
message string within the standard Oracle Database error message string.
Returns
This function returns OCIEXTPROC_SUCCESS if the call succeeds. It returns
OCIEXTPROC_ERROR if the call fails.
Related Topics
•

OCIExtProcRaiseExcp()
Raises an Exception to PL/SQL.

29.3 Cartridge Services — Memory Services
Lists and describes cartridge services memory services functions.
Table 29-2 lists the memory services functions that are described in this section.
Table 29-2

Memory Services Functions

Function

Purpose

OCIDurationBegin()

Start a user duration

OCIDurationEnd()

Terminate a user duration

OCIMemoryAlloc()

Allocate memory of a given size from a
given duration

OCIMemoryFree()

Free a memory chunk

OCIMemoryResize()

Resize a memory chunk

See Also:
Oracle Database Data Cartridge Developer's Guide for more information
about using these functions

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29.3.1 OCIDurationBegin()
Starts a user duration.
Purpose
Starts a user duration.
Syntax
sword OCIDurationBegin ( OCIEnv
OCIError
const OCISvcCtx
OCIDuration
OCIDuration

*env,
*err,
*svc,
parent,
*duration );

Parameters
env (IN/OUT)
The OCI environment handle. This should be passed as NULL for cartridge services.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
svc (IN)
The OCI service context handle.
parent (IN)
The duration number of the parent duration. It is one of the following:
•

A user duration that was previously created

•

OCI_DURATION_STATEMENT

•

OCI_DURATION_SESSION

duration (OUT)
An identifier unique to the newly created user duration.
Comments
This function starts a user duration. A user can have multiple active user durations
simultaneously. The user durations do not have to be nested. The duration parameter
is used to return a number that uniquely identifies the duration created by this call.
Note that the environment and service context parameters cannot both be NULL.
Related Topics
•

OCIDurationEnd()
Terminates a user duration for a temporary LOB.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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29.3.2 OCIDurationEnd()
Terminates a user duration.
Purpose
Terminates a user duration.
Syntax
sword OCIDurationEnd ( OCIEnv
OCIError
const OCISvcCtx
OCIDuration

*env,
*err,
*svc,
duration );

Parameters
env (IN/OUT)
The OCI environment handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
svc (IN)
OCI service context (this should be passed as NULL for cartridge services; otherwise, it
should be non-NULL).
duration (IN)
A user duration previously created by OCIDurationBegin().
Comments
This function terminates a user duration.
Note that the environment and service context parameters cannot both be NULL.

29.3.3 OCIMemoryAlloc()
Allocates memory of a given size from a given duration.
Purpose
Allocates memory of a given size from a given duration.
Syntax
sword OCIMemoryAlloc( void
*hndl,
OCIError
*err,
void
**mem,
OCIDuration dur,
ub4
size,
ub4
flags );

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Parameters
hndl (IN)
The OCI environment handle (OCIEnv *) if dur is OCI_DURATION_PROCESS; otherwise, the
user session handle (OCISession *).
err (IN)
The error handle.
mem (OUT)
Memory allocated.
dur (IN)
A previously created user duration or one of these values:
OCI_DURATION_CALLOUT
OCI_DURATION_STATEMENT
OCI_DURATION_SESSION
OCI_DURATION_PROCESS

size (IN)
Size of memory to be allocated.
flags (IN)
Set the OCI_MEMORY_CLEARED bit to get memory that has been cleared.
Comments
To allocate memory for the duration of the callout of the agent, that is, external
procedure duration, use OCIExtProcAllocCallMemory() or OCIMemoryAlloc() with dur as
OCI_DURATION_CALLOUT.
Returns
Error code.
Related Topics
•

OCIExtProcAllocCallMemory()
Allocates N bytes of memory for the duration of the external procedure.

29.3.4 OCIMemoryFree()
Frees a memory chunk.
Purpose
Frees a memory chunk.
Syntax
sword OCIMemoryFree ( void
*hndl,
OCIError *err,
void
*mem );

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Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN)
The error handle.
mem (IN/OUT)
Pointer to memory allocated previously using OCIMemoryAlloc().
Returns
Error code.
Related Topics
•

OCIMemoryAlloc()
Allocates memory of a given size from a given duration.

29.3.5 OCIMemoryResize()
Resizes a memory chunk to a new size.
Purpose
Resizes a memory chunk to a new size.
Syntax
sword OCIMemoryResize( void
OCIError
void
ub4
ub4

*hndl,
*err,
**mem,
newsize,
flags );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN)
The error handle.
mem (IN/OUT)
Pointer to memory allocated previously using OCIMemoryAlloc().
newsize (IN)
Size of memory requested.
flags (IN)
Set the OCI_MEMORY_CLEARED bit to get memory that has been cleared.
Comments
Memory must have been allocated before this function can be called to resize.

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Returns
Error code.
Related Topics
•

OCIMemoryAlloc()
Allocates memory of a given size from a given duration.

29.4 Cartridge Services — Maintaining Context
Lists and describes cartridge services maintaining context functions.
Table 29-3 lists the maintaining context functions that are described in this section.
Table 29-3

Maintaining Context Functions

Function

Purpose

OCIContextClearValue()

Remove the value stored in the context

OCIContextGenerateKey()

Return a unique 4-byte value each time it is
called

OCIContextGetValue()

Return the value stored in the context

OCIContextSetValue()

Save a value (or address) for a particular
duration

See Also:
Oracle Database Data Cartridge Developer's Guide for more information
about using these functions

29.4.1 OCIContextClearValue()
Removes the value that is stored in the context associated with the given key (by
calling OCIContextSetValue()).
Purpose
Removes the value that is stored in the context associated with the given key (by
calling OCIContextSetValue()).
Syntax
sword OCIContextClearValue( void
OCIError
ub1
ub1

*hndl,
*err,
*key,
keylen );

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Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN)
The error handle.
key (IN)
Unique key value.
keylen (IN)
Length of the key. Maximum value is 255 bytes or UB1MAXVAL - 1.
Comments
An error is returned when a nonexistent key is passed.
Returns
•

If the operation succeeds, the function returns OCI_SUCCESS.

•

If the operation fails, the function returns OCI_ERROR.

29.4.2 OCIContextGenerateKey()
Returns a unique, 4-byte value each time it is called.
Purpose
Returns a unique, 4-byte value each time it is called.
Syntax
sword OCIContextGenerateKey( void
*hndl,
OCIError *err,
ub4
*key );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN)
The error handle.
key (IN)
Unique key value.
Comments
This value is unique for each session.
Returns
•

If the operation succeeds, the function returns OCI_SUCCESS.

•

If the operation fails, the function returns OCI_ERROR.

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29.4.3 OCIContextGetValue()
Returns the value that is stored in the context associated with the given key (by calling
OCIContextSetValue()).
Purpose
Returns the value that is stored in the context associated with the given key (by calling
OCIContextSetValue()).
Syntax
sword OCIContextGetValue( void
*hndl,
OCIError *err,
ub1
*key,
ub1
keylen,
void
**ctx_value );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN)
The error handle.
key (IN)
Unique key value.
keylen (IN)
Length of the key. Maximum value is 255 bytes or UB1MAXVAL - 1.
ctx_value (IN)
Pointer to the value stored in the context (NULL if no value was stored).
Comments
For ctx_value, a pointer to a preallocated pointer for the stored context to be returned
is required.
Returns
•

If the operation succeeds, the function returns OCI_SUCCESS.

•

If the operation fails, the function returns OCI_ERROR.

29.4.4 OCIContextSetValue()
Saves a value (or address) for a particular duration.
Purpose
Saves a value (or address) for a particular duration.

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Syntax
sword OCIContextSetValue( void
OCIError
OCIDuration
ub1
ub1
void

*hndl,
*err,
duration,
*key,
keylen,
*ctx_value );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN)
The error handle.
duration (IN)
One of these values (a previously created user duration):
OCI_DURATION_STATEMENT
OCI_DURATION_SESSION

key (IN)
Unique key value.
keylen (IN)
Length of the key. Maximum value is 255 bytes or UB1MAXVAL - 1.
ctx_value (IN)
Pointer that is saved in the context.
Comments
The context value being stored must be allocated out of memory of duration greater
than or equal to the duration being passed in. The key being passed in should be
unique in this session. Trying to save a context value under the same key and duration
again results in overwriting the old context value with the new one. Typically, a client
allocates a structure, stores its address in the context using this call, and gets this
address in a separate call using OCIContextGetValue(). The (key, value) association
can be explicitly removed by calling OCIContextClearValue(), or else it goes away at the
end of the duration.
Returns
•

If the operation succeeds, the function returns OCI_SUCCESS.

•

If the operation fails, the function returns OCI_ERROR.

Related Topics
•

OCIContextClearValue()
Removes the value that is stored in the context associated with the given key (by
calling OCIContextSetValue()).

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29.5 Cartridge Services — Parameter Manager Interface
Lists and describes cartridge services parameter manager interface functions.
Table 29-4 lists the parameter manager interface functions that are described in this
section.
Table 29-4

Parameter Manager Interface Functions

Function

Purpose

OCIExtractFromFile()

Process the keys and their values in the
given file

OCIExtractFromList()

Generate a list of values for the parameter
denoted by index in the parameter list

OCIExtractFromStr()

Process the keys and the their values in
the given string

OCIExtractInit()

Initialize the parameter manager

OCIExtractReset()

Reinitialize memory

OCIExtractSetKey()

Register information about a key with the
parameter manager

OCIExtractSetNumKeys()

Inform the parameter manager of the
number of keys that are to be registered

OCIExtractTerm()

Release all dynamically allocated storage

OCIExtractToBool()

Get the Boolean value for the specified key

OCIExtractToInt()

Get the integer value for the specified key

OCIExtractToList()

Generate a list of parameters from the
parameter structures that are stored in
memory

OCIExtractToOCINum()

Get the number value for the specified key

OCIExtractToStr()

Get the string value for the specified key

See Also:
Oracle Database Data Cartridge Developer's Guide for more information
about using these functions

29.5.1 OCIExtractFromFile()
Processes the keys and their values in the given file.
Purpose
Processes the keys and their values in the given file.

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Syntax
sword OCIExtractFromFile( void
OCIError
ub4
OraText

*hndl,
*err,
flag,
*filename );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
flag (IN)
Zero or has one or more of the following bits set:
OCI_EXTRACT_CASE_SENSITIVE
OCI_EXTRACT_UNIQUE_ABBREVS
OCI_EXTRACT_APPEND_VALUES

filename (IN)
A NULL-terminated file name string.
Comments
OCIExtractSetNumKeys() and OCIExtractSetKey() functions must be called to define all of

the keys before this routine is called.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIExtractSetNumKeys()
Informs the parameter manager of the number of keys that are to be registered.

•

OCIExtractSetKey()
Registers information about a key with the parameter manager.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.2 OCIExtractFromList()
Generates a list of values for the parameter denoted by index in the parameter list.
Purpose
Generates a list of values for the parameter denoted by index in the parameter list.
Syntax
sword OCIExtractFromList( void
OCIError
uword
OraText

*hndl,
*err,
index,
**name,

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ub1
uword
void

*type,
*numvals,
***values );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
index (IN)
Which parameter to retrieve from the parameter list.
name (OUT)
The name of the key for the current parameter.
type (OUT)
Type of the current parameter:
OCI_EXTRACT_TYPE_STRING
OCI_EXTRACT_TYPE_INTEGER
OCI_EXTRACT_TYPE_OCINUM
OCI_EXTRACT_TYPE_BOOLEAN

numvals (OUT)
Number of values for this parameter.
values (OUT)
The values for this parameter.
Comments
OCIExtractToList() must be called prior to calling this routine to generate the

parameter list from the parameter structures that are stored in memory.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIExtractToList()
Generates a list of parameters from the parameter structures that are stored in
memory.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.3 OCIExtractFromStr()
Processes the keys and their values in the given string.
Purpose
Processes the keys and their values in the given string.

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Syntax
sword OCIExtractFromStr( void
OCIError
ub4
OraText

*hndl,
*err,
flag,
*input );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. For diagnostic information call OCIErrorGet().
flag (IN)
Zero or has one or more of the following bits set:
OCI_EXTRACT_CASE_SENSITIVE
OCI_EXTRACT_UNIQUE_ABBREVS
OCI_EXTRACT_APPEND_VALUES

input (IN)
A NULL-terminated input string.
Comments
OCIExtractSetNumKeys() and OCIExtractSetKey() functions must be called to define all of

the keys before this routine is called.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIExtractSetNumKeys()
Informs the parameter manager of the number of keys that are to be registered.

•

OCIExtractSetKey()
Registers information about a key with the parameter manager.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.4 OCIExtractInit()
Initializes the parameter manager.
Purpose
Initializes the parameter manager.
Syntax
sword OCIExtractInit( void
OCIError

*hndl,
*err);

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Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Comments
This function must be called before calling any other parameter manager routine, and
it must be called only once. The globalization support information is stored inside the
parameter manager context and used in subsequent calls to OCIExtract functions.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.5 OCIExtractReset()
Frees the memory currently used for parameter storage, key definition storage, and
parameter value lists and reinitializes the structure.
Purpose
Frees the memory currently used for parameter storage, key definition storage, and
parameter value lists and reinitializes the structure.
Syntax
sword OCIExtractReset( void
*hndl,
OCIError *err );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR,

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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29.5.6 OCIExtractSetKey()
Registers information about a key with the parameter manager.
Purpose
Registers information about a key with the parameter manager.
Syntax
sword OCIExtractSetKey( void
OCIError
const text
ub1
ub4
const void
const sb4
const text

*hndl,
*err,
*name,
type,
flag,
*defval,
*intrange,
*strlist );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
name (IN)
The name of the key.
type (IN)
The type of the key:
OCI_EXTRACT_TYPE_INTEGER
OCI_EXTRACT_TYPE_OCINUM
OCI_EXTRACT_TYPE_STRING
OCI_EXTRACT_TYPE_BOOLEAN

flag (IN)
Set to OCI_EXTRACT_MULTIPLE if the key can take multiple values or 0 otherwise.
defval (IN)
Set to the default value for the key. It can be NULL if there is no default. A string default
must be a (text*) type, an integer default must be an (sb4*) type, and a Boolean
default must be a (ub1*) type.
intrange (IN)
Starting and ending values for the allowable range of integer values; can be NULL if the
key is not an integer type or if all integer values are acceptable.
strlist (IN)
List of all acceptable text strings for the key ended with 0 (or NULL). Can be NULL if the
key is not a string type or if all text values are acceptable.

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Comments
This routine must be called after calling OCIExtractSetNumKeys() and before calling
OCIExtractFromFile() or OCIExtractFromStr().
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIExtractSetNumKeys()
Informs the parameter manager of the number of keys that are to be registered.

•

OCIExtractFromFile()
Processes the keys and their values in the given file.

•

OCIExtractFromStr()
Processes the keys and their values in the given string.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.7 OCIExtractSetNumKeys()
Informs the parameter manager of the number of keys that are to be registered.
Purpose
Informs the parameter manager of the number of keys that are to be registered.
Syntax
sword OCIExtractSetNumKeys( void
*hndl,
CIError *err,
uword
numkeys );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
numkeys (IN)
The number of keys that are to be registered with OCIExtractSetKey().
Comments
This routine must be called prior to the first call of OCIExtractSetKey().
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

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Related Topics
•

OCIExtractSetKey()
Registers information about a key with the parameter manager.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.8 OCIExtractTerm()
Releases all dynamically allocated storage.
Purpose
Releases all dynamically allocated storage.
Syntax
sword OCIExtractTerm( void
*hndl,
OCIError *err );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Comments
This function may perform other internal bookkeeping functions. It must be called
when the parameter manager is no longer being used, and it must be called only once.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.9 OCIExtractToBool()
Gets the Boolean value for the specified key.
Purpose
The valno'th value (starting with 0) is returned.
Syntax
sword OCIExtractToBool( void
*hndl,
OCIError *err,
OraText *keyname,
uword
valno,
ub1
*retval );

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Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
keyname (IN)
Key name.
valno (IN)
Which value to get for this key.
retval (OUT)
The actual Boolean value.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; OCI_NO_DATA; or OCI_ERROR.
OCI_NO_DATA means that there is no valno'th value for this key.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.10 OCIExtractToInt()
Gets the integer value for the specified key.
Purpose
The valno'th value (starting with 0) is returned.
Syntax
sword OCIExtractToInt( void
*hndl,
OCIError *err,
OraText *keyname,
uword
valno,
sb4
*retval );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
keyname (IN)
Keyname (IN).

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valno (IN)
Which value to get for this key.
retval (OUT)
The actual integer value.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; OCI_NO_DATA; or OCI_ERROR.
OCI_NO_DATA means that there is no valno'th value for this key.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.11 OCIExtractToList()
Generates a list of parameters from the parameter structures that are stored in
memory.
Purpose
Must be called before OCIExtractValues() is called.
Syntax
sword OCIExtractToList( void
*hndl,
OCIError *err,
uword
*numkeys );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
numkeys (OUT)
The number of distinct keys stored in memory.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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29.5.12 OCIExtractToOCINum()
Gets the OCINumber value for the specified key.
Purpose
The valno'th value (starting with 0) is returned.
Syntax
sword OCIExtractToOCINum( void
OCIError
OraText
uword
OCINumber

*hndl,
*err,
*keyname,
valno,
*retval );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
keyname (IN)
Key name.
valno (IN)
Which value to get for this key.
retval (OUT)
The actual OCINumber value.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; OCI_NO_DATA; or OCI_ERROR.
OCI_NO_DATA means that there is no valno'th value for this key.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.5.13 OCIExtractToStr()
Gets the string value for the specified key.
Purpose
The valno'th value (starting with 0) is returned.
Syntax
sword OCIExtractToStr( void
OCIError
OraText

*hndl,
*err,
*keyname,

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uword
OraText
uword

valno,
*retval,
buflen );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
keyname (IN)
Key name.
valno (IN)
Which value to get for this key.
retval (OUT)
The actual NULL-terminated string value.
buflen
The length of the buffer for retval.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; OCI_NO_DATA; or OCI_ERROR.
OCI_NO_DATA means that there is no valno'th value for this key.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6 Cartridge Services — File I/O Interface
Lists and describes cartridge services file I/O interface functions.
Table 29-5 lists the file I/O interface functions that are described in this section.
Table 29-5

File I/O Interface Functions

Function

Purpose

OCIFileClose()

Close a previously opened file

OCIFileExists()

Test to see if the file exists

OCIFileFlush()

Write buffered data to a file

OCIFileGetLength()

Get the length of a file

OCIFileInit()

Initialize the OCIFile package

OCIFileOpen()

Open a file

OCIFileRead()

Read from a file into a buffer

OCIFileSeek()

Change the current position in a file

OCIFileTerm()

Terminate the OCIFile package

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Table 29-5

(Cont.) File I/O Interface Functions

Function

Purpose

OCIFileWrite()

Write buflen bytes into the file

See Also:
Oracle Database Data Cartridge Developer's Guide for more information
about using these functions

OCIFileObject
The OCIFileObject data structure holds information about the way in which a file should
be opened and the way in which it is accessed after it has been opened. When this
structure is initialized by OCIFileOpen(), it becomes an identifier through which
operations can be performed on that file. It is a necessary parameter to every function
that operates on open files. This data structure is opaque to OCIFile clients. It is
initialized by OCIFileOpen() and terminated by OCIFileClose().

29.6.1 OCIFileClose()
Closes a previously opened file.
Purpose
Closes a previously opened file.
Syntax
sword OCIFileClose( void
*hndl,
OCIError
*err,
OCIFileObject *filep );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filep (IN/OUT)
A pointer to a file identifier to be closed.
Comments
Once this function returns OCI_SUCCESS, the OCIFileObject structure pointed to by
filep is destroyed. Therefore, you should not attempt to access this structure after this
function returns OCI_SUCCESS.

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Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.2 OCIFileExists()
Tests to see if the file exists.
Purpose
Tests to see if the file exists.
Syntax
sword OCIFileExists( void
OCIError
OraText
OraText
ub1

*hndl,
*err,
*filename,
*path,
*flag );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filename (IN)
The file name as a NULL-terminated string.
path (IN)
The path of the file as a NULL-terminated string.
flag (OUT)
Set to TRUE if the file exists or FALSE if it does not.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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29.6.3 OCIFileFlush()
Writes buffered data to a file.
Purpose
Writes buffered data to a file.
Syntax
sword OCIFileFlush( void
*hndl
OCIError
*err,
OCIFileObject *filep );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filep (IN/OUT)
A file identifier that uniquely references the file.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.4 OCIFileGetLength()
Gets the length of a file.
Purpose
Gets the length of a file.
Syntax
sword OCIFileGetLength( void
OCIError
OraText
OraText
ubig_ora

*hndl,
*err,
*filename,
*path,
*lenp );

Parameters
hndl (IN)
The OCI environment or user session handle.

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err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filename (IN)
The file name as a NULL-terminated string.
path (IN)
The path of the file as a NULL-terminated string.
lenp (OUT)
Set to the length of the file in bytes.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.5 OCIFileInit()
Initializes the OCIFile package.
Purpose
This function must be called before any other OCIFile routine is called.
Syntax
sword OCIFileInit( void
*hndl,
OCIError *err );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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29.6.6 OCIFileOpen()
Opens a file.
Purpose
Opens a file.
Syntax
sword OCIFileOpen( void
*hndl,
OCIError
*err,
OCIFileObject **filep,
OraText
*filename,
OraText
*path,
ub4
mode,
ub4
create,
ub4
type );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filep (IN/OUT)
The file identifier.
filename (IN)
The file name as a NULL-terminated string.
path (IN)
The path of the file as a NULL-terminated string.
mode (IN)
The mode in which to open the file. Valid modes are
OCI_FILE_READ_ONLY
OCI_FILE_WRITE_ONLY
OCI_FILE_READ_WRITE

create (IN)
Indicates if the file is to be created if it does not exist. Valid values are:
OCI_FILE_TRUNCATE — Create a file regardless of whether it exists. If the file exists,
overwrite the existing file.
OCI_FILE_EXCL — Fail if the file exists; otherwise, create a file.
OCI_FILE_CREATE — Open the file if it exists, and create it if it does not.
OCI_FILE_APPEND — Set the file pointer to the end of the file prior to writing. This flag
can be used with the logical operator OR with OCI_FILE_CREATE.
type (IN)
File type. Valid values are:
OCI_FILE_TEXT

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OCI_FILE_BIN
OCI_FILE_STDIN
OCI_FILE_STDOUT
OCI_FILE_STDERR

Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.7 OCIFileRead()
Reads from a file into a buffer.
Purpose
Reads from a file into a buffer.
Syntax
sword OCIFileRead( void
OCIError
OCIFileObject
void
ub4
ub4

*hndl,
*err,
*filep,
*bufp,
bufl,
*bytesread );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filep (IN/OUT)
A file identifier that uniquely references the file.
bufp (IN)
The pointer to a buffer into which the data is read. The length of the allocated memory
is assumed to be bufl.
bufl (IN)
The length of the buffer in bytes.
bytesread (OUT)
The number of bytes read.
Comments
As many bytes as possible are read into the user buffer. The read ends either when
the user buffer is full, or when it reaches end-of-file.

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Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.8 OCIFileSeek()
Changes the current position in a file.
Purpose
Changes the current position in a file.
Syntax
sword OCIFileSeek( void
OCIError
OCIFileObject
uword
ubig_ora
sb1

*hndl,
*err,
*filep,
origin,
offset,
dir );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filep (IN/OUT)
A file identifier that uniquely references the file.
origin(IN)
The starting point from which to seek. Use one of the following values:
OCI_FILE_SEEK_BEGINNING (beginning)
OCI_FILE_SEEK_CURRENT (current position)
OCI_FILE_SEEK_END (end of file)
offset (IN)
The number of bytes from the origin where reading begins.
dir (IN)
The direction to go from the origin.

Note:
The direction can be either OCIFILE_FORWARD or OCIFILE_BACKWARD.

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Comments
This function allows a seek past the end of the file. Reading from such a position
causes an end-of-file condition to be reported. Writing to such a position does not work
on all file systems. This is because some systems do not allow files to grow
dynamically. They require that files be preallocated with a fixed size. Note that this
function performs a seek to a byte location.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.9 OCIFileTerm()
Terminates the OCIFile package.
Purpose
This function must be called after the OCIFile package is no longer being used.
Syntax
sword OCIFileTerm( void
*hndl,
OCIError *err );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.6.10 OCIFileWrite()
Writes buflen bytes into the file.
Purpose
Writes buflen bytes into the file.

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Syntax
sword OCIFileWrite( void
OCIError
OCIFileObject
void
ub4
ub4

*hndl,
*err,
*filep,
*bufp,
buflen,
*byteswritten );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
filep (IN/OUT)
A file identifier that uniquely references the file.
bufp(IN)
The pointer to a buffer from which the data is written. The length of the allocated
memory is assumed to be buflen.
buflen (IN)
The length of the buffer in bytes.
byteswritten (OUT)
The number of bytes written.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.7 Cartridge Services — String Formatting Interface
Lists and describes cartridge services string formatting functions.
Table 29-6 lists the string formatting functions that are described in this section.
Table 29-6

String Formatting Functions

Function

Purpose

OCIFormatInit()

Initialize the OCIFormat package

OCIFormatString()

Write a text string into the supplied text buffer

OCIFormatTerm()

Terminate the OCIFormat package

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See Also:
Oracle Database Data Cartridge Developer's Guide for more information
about using these functions

29.7.1 OCIFormatInit()
Initializes the OCIFormat package.
Purpose
Initializes the OCIFormat package.
Syntax
sword OCIFormatInit( void
*hndl,
OCIError *err);

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Comments
This routine must be called before calling any other OCIFormat routine, and it must be
called only once.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.7.2 OCIFormatString()
Writes a text string into the supplied text buffer using the argument list submitted to it
and in accordance with the format string given.
Purpose
Writes a text string into the supplied text buffer using the argument list submitted to it
and in accordance with the format string given.
Syntax
sword OCIFormatString( void
OCIError

*hndl,
*err,

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OraText
sbig_ora
sbig_ora
const OraText

*buffer,
bufferLength,
*returnLength,
*formatString,... );

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
buffer (OUT)
The buffer that contains the string.
bufferLength (IN)
The length of the buffer in bytes.
returnLength (OUT)
The number of bytes written to the buffer (excluding the terminating NULL).
formatString (IN)
The format string, which can be any combination of literal text and format
specifications. A format specification is delimited by the percent character (%) and is
followed by any number (including none) of optional format modifiers, and terminated
by a mandatory format code. If the format string ends with %, that is, with no format
modifiers, or format specifier following it, then no action is taken. The format modifiers
and format codes available are described in Table 29-7 and Table 29-8.
... (IN)
Variable number of arguments of the form OCIFormat type wrapper(variable) where
variable must be a variable containing the value to be used. No constant values or
expressions are allowed as arguments to the OCIFormat type wrappers; The OCIFormat
type wrappers that are available are listed next. The argument list must be terminated
with OCIFormatEnd.
OCIFormatUb1(ub1 variable);
OCIFormatUb2(ub2 variable);
OCIFormatUb4(ub4 variable);
OCIFormatUword(uword variable);
OCIFormatUbig_ora(ubig_ora variable);
OCIFormatSb1(sb1 variable);
OCIFormatSb2(sb2 variable);
OCIFormatSb4(sb4 variable);
OCIFormatSword(sword variable);
OCIFormatSbig_ora(sbig_ora variable);
OCIFormatEb1(eb1 variable);
OCIFormatEb2(eb2 variable);
OCIFormatEb4(eb4 variable);
OCIFormatEword(eword variable);
OCIFormatChar (text variable);
OCIFormatText(const text *variable);
OCIFormatDouble(double variable);
OCIFormatDvoid(const dvoid *variable);

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OCIFormatEnd

Comments
The first call to this routine must be preceded by a call to the OCIFormatInit() routine
that initializes the OCIFormat package for use. When this routine is no longer needed
terminate the OCIFormat package by a call to the OCIFormatTerm() routine.
Format Modifiers
A format modifier alters or extends the format specification, allowing more specialized
output. The format modifiers, as described in Table 29-7, can be in any order and are
all optional.
Table 29-7

Format Modifier Flags

Flag

Operation

'-'

Left-justify the output in the field.

'+'

Always print a sign ('+' or '–') for numeric types.

' '

If a number's sign is not printed, then print a space in the sign position.

'0'

Pad numeric output with zeros, not spaces.

•

If both the '+' and ' ' flags are used in the same format specification, then the ' '
flag is ignored.

•

If both the '-' and '0' flags are used in the same format specification, then the '-'
flag is ignored.

Alternate output:
•

For the octal format code, add a leading zero.

•

For the hexadecimal format code, add a leading '0x'.

•

For floating-point format codes, the output always has a radix character.

Field Width
 where  is a number specifying a minimum field width. The converted argument
is printed in a field at least this wide, and wider if necessary. If the converted argument
takes up fewer display positions than the field width, it is padded on the left (or right for
left justification) to make up the field width. The padding character is normally a space,
but it is a zero if the zero padding flag was specified. The special character '*' may be
used for  and indicates the current argument is to be used for the field width value;
the actual field or precision follows as the next sequential argument.

Precision
. (a period followed by the number 
), specifies the maximum number of display

positions to print from a string, or digits after the radix point for a decimal number, or
the minimum number of digits to print for an integer type (leading zeros are added to
make up the difference). The special character '*' may be used for 
, indicating that
the current argument contains the precision value.
Argument Index
() where  is an integer index into the argument list with the first argument being
1. If no argument index is specified in a format specification, the first argument is

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selected. The next time no argument index is specified in a format specification, the
second argument is selected, and so on. Format specifications with and without
argument indexes can be in any order and are independent of each other in operation.
For example, the format string "%u %(4)u %u %(2)u %u" selects the first, fourth, second,
second, and third arguments given to OCIFormatString().
Format Codes
A format code specifies how to format an argument that is being written to a string.
Note that these format codes, as described in Table 29-8, can appear in uppercase,
which causes all alphabetic characters in the output to appear in uppercase except for
text strings, which are not converted.
Table 29-8
String

Format Codes to Specify How to Format an Argument Written to a

Codes

Operation

'c'

Single-byte character in the compiler character set

'd'

Signed decimal integer

'e'

Exponential (scientific) notation of the form [-][...]e+[]
where  is the radix character for the current language and  is any single
digit; the default precision is given by the constant OCIFormatDP. The precision
may be optionally specified as a format modifier. Using a precision of 0
suppresses the radix character; the exponent is always printed in at least 2
digits, and can take up to 3 (for example, 1e+01, 1e+10, and 1e+100).

'f'

Fixed decimal notation of the form [-][...][...] where  is the
appropriate radix character for the current language and  is any single digit;
the precision may be optionally specified as a format modifier. Using a precision
of 0 suppresses the radix character. The default precision is given by the
constant OCIFormatDP.

'g'

Variable floating-point notation; chooses 'e' or 'f', selecting 'f'' if the number
fits in the specified precision (default precision if unspecified), and choosing 'e'
only if exponential format allows more significant digits to be printed; does not
print a radix character if number has no fractional part

'i'

Identical to 'd'

'o'

Unsigned octal integer

'p'

Operating system-specific pointer printout

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Table 29-8 (Cont.) Format Codes to Specify How to Format an Argument
Written to a String
Codes

Operation

's'

Prints an argument using the default format code for its type:
ociformatub, ociformatuword, ociformatubig_ora, ociformateb, and
ociformateword.
The format code used is 'u'.
ociformatsb, ociformatsword, and ociformatsbig_ora.
The format code used is 'd'.
ociformatchar
The format code used is 'c'.
ociformattext
Prints text until trailing NULL is found.
ociformatdouble
The format code used is 'g'.
ociformatdvoid
The format code used is 'p'.
' %' - print a '%'.

'u'

Unsigned decimal integer

'x'

Unsigned hexadecimal integer

Example
Using OCIFormatString() to Format a Date Two Different Ways for Two Countries
/*
/*
/*
/*
/*
/*

This example shows the power of arbitrary argument
*/
selection in the context of internationalization. A */
date is formatted in two different ways for two different */
countries according to the format string, yet the
*/
argument list submitted to OCIFormatString remains
*/
invariant.
*/

text
ub1
OCIError
void
sbig_ora

buffer[255];
day, month, year;
*err;
*hndl;
returnLen;

/* Set the date. */
day = 10;
month = 3;
year = 97;
/* Work out the date in United States style: mm/dd/yy */
OCIFormatString(hndl, err,
buffer, (sbig_ora)sizeof(buffer), &returnLen
(const text *)"%(2)02u/%(1)02u/%(3)02u",
OCIFormatUb1(day),
OCIFormatUb1(month),
OCIFormatUb1(year),
OCIFormatEnd);
/* Buffer is "03/10/97". */

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/* Work out the date in New Zealand style: dd/mm/yy */
OCIFormatString(hndl, err,
buffer, (sbig_ora)sizeof(buffer), &returnLen
(const text *)"%(1)02u/%(2)02u/%(3)02u",
OCIFormatUb1(day),
OCIFormatUb1(month),
OCIFormatUb1(year),
OCIFormatEnd);
/* Buffer is "10/03/97". */

Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIFormatInit()
Initializes the OCIFormat package.

•

OCIFormatTerm()
Terminates the OCIFormat package.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

29.7.3 OCIFormatTerm()
Terminates the OCIFormat package.
Purpose
Terminates the OCIFormat package.
Syntax
sword OCIFormatTerm( void
*hndl,
OCIError *err);

Parameters
hndl (IN)
The OCI environment or user session handle.
err (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
Comments
This function must be called after the OCIFormat package is no longer being used,
and it must be called only once.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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30
OCI Any Type and Data Functions
This chapter describes the OCI Any Type and Data functions.

See Also:
For code examples, see the demonstration programs included with your
Oracle Database installation. For additional information, see OCI
Demonstration Programs.

This chapter contains these topics:
•

Introduction to Any Type and Data Interfaces

•

OCI Type Interface Functions

•

OCI Any Data Interface Functions

•

OCI Any Data Set Interface Functions

30.1 Introduction to Any Type and Data Interfaces
This section describes the OCI Any Type and Data functions in detail.

See Also:
"AnyType, AnyData, and AnyDataSet Interfaces"

30.1.1 Conventions for OCI Functions
Describes the conventions for OCI functions. The entries for each function may also
contain function return values.
See the Conventions for OCI Functions for the conventions used in describing each
function.
The OCI Any Type and Data functions typically return one of the values described in
the following table.
Table 30-1

Function Return Values

Return Value

Meaning

OCI_SUCCESS

The operation succeeded.

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Table 30-1

(Cont.) Function Return Values

Return Value

Meaning

OCI_ERROR

The operation failed. The specific error can be
retrieved by calling OCIErrorGet() on the error handle
passed to the function.

OCI_INVALID_HANDLE

The OCI handle passed to the function is invalid.

See Also:
Error Handling in OCI for more information about return codes and error
handling

30.2 OCI Type Interface Functions
Table 30-2 lists the Type Interface functions that are described in this section.
Table 30-2

Type Interface Functions

Function

Purpose

OCITypeAddAttr()

Add an attribute to an object type that was
constructed earlier with typecode
OCI_TYPECODE_OBJECT

OCITypeBeginCreate()

Begin the construction process for a transient
type. The type is anonymous (no name).

OCITypeEndCreate()

Finish construction of a type description.
Subsequently, only access is allowed.

OCITypeSetBuiltin()

Set built-in type information. This call can be
made only if the type has been constructed
with a built-in typecode
(OCI_TYPECODE_NUMBER, and so on).

OCITypeSetCollection()

Set collection type information. This call can
be made only if the type has been constructed
with a collection typecode.

30.2.1 OCITypeAddAttr()
Adds an attribute to an object type that was constructed earlier with typecode
OCI_TYPECODE_OBJECT.

Purpose
Adds an attribute to an object type that was constructed earlier with typecode
OCI_TYPECODE_OBJECT.

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Syntax
sword OCITypeAddAttr ( OCISvcCtx
OCIError
OCIType
const text
ub4
OCIParam

*svchp,
*errhp,
*type,
*a_name,
a_length,
*attr_info );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
type (IN/OUT)
The type description that is being constructed.
a_name (IN) [optional]
The name of the attribute.
a_length (IN) [optional]
The length of the attribute name, in bytes.
attr_info (IN)
Information about the attribute. It is obtained by allocating an OCIParam parameter
handle and setting type information in the OCIParam using OCIAttrSet() calls.
Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.2.2 OCITypeBeginCreate()
Begins the construction process for a transient type. The type is anonymous (no
name).
Purpose
Begins the construction process for a transient type. The type is anonymous (no
name).
Syntax
sword OCITypeBeginCreate ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCITypeCode
tc,
OCIDuration
dur,
OCIType
**type );

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Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tc (IN)
The typecode for the type. The typecode could correspond to an object type or a builtin type.
Currently, the permissible values for user defined types are:
•

OCI_TYPECODE_OBJECT for an object type (structured)

•

OCI_TYPECODE_VARRAY for a VARRAY collection type

•

OCI_TYPECODE_TABLE for a nested table collection type

For object types, call OCITypeAddAttr() to add each of the attribute types. For collection
types, call OCITypeSetCollection(). Subsequently, call OCITypeEndCreate() to finish the
creation process.
The permissible values for built-in typecodes are specified in "Typecodes". Additional
information about built-in types (precision, scale for numbers, character set information
for VARCHAR2s, and so on) if any, must be set with a subsequent call to
OCITypeSetBuiltin(). Finally, you must use OCITypeEndCreate() to finish the creation
process.
dur (IN)
The allocation duration for the type. It is one of these:
•

A user duration that was previously created. It can be created by using
OCIDurationBegin().

•

A predefined duration, such as OCI_DURATION_SESSION.

type (OUT)
The OCIType (Type Descriptor) that is being constructed.
Comments
To create a persistent named type, use the SQL statement CREATE TYPE. Transient
types have no identity. They are pure values.
Related Topics
•

OCITypeAddAttr()
Adds an attribute to an object type that was constructed earlier with typecode
OCI_TYPECODE_OBJECT.

•

OCITypeSetCollection()
Sets collection type information.

•

OCITypeEndCreate()
Finishes construction of a type description. Subsequently, only access is allowed.

•

OCITypeSetBuiltin()
Sets built-in type information.

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•

OCIDurationBegin()
Starts a user duration.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.2.3 OCITypeEndCreate()
Finishes construction of a type description. Subsequently, only access is allowed.
Purpose
Finishes construction of a type description. Subsequently, only access is allowed.
Syntax
sword OCITypeEndCreate ( OCISvcCtx *svchp,
OCIError *errhp,
OCIType
*type );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
type (IN/OUT)
The type description that is being constructed.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.2.4 OCITypeSetBuiltin()
Sets built-in type information.
Purpose
This call can be made only if the type has been constructed with a built-in typecode
(OCI_TYPECODE_NUMBER, and so on).
Syntax
sword OCITypeSetBuiltin ( OCISvcCtx
OCIError
OCIType
OCIParam

*svchp,
*errhp,
*type,
*builtin_info );

Parameters
svchp (IN)
The OCI service context.

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errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
type (IN/OUT)
The type description that is being constructed.
builtin_info (IN)
Provides information about the built-in type (precision, scale, character set, and so
on). It is obtained by allocating an OCIParam parameter handle and setting type
information in the OCIParam using OCIAttrSet() calls.
Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.2.5 OCITypeSetCollection()
Sets collection type information.
Purpose
This call can be made only if the type has been constructed with a collection typecode.
Syntax
sword OCITypeSetCollection ( OCISvcCtx
OCIError
OCIType
OCIParam
ub4

*svchp,
*errhp,
*type,
*collelem_info,
coll_count );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
type (IN/OUT)
The type descriptor that is being constructed.
collelem_info (IN)
collelem_info provides information about the collection element. It is obtained by
allocating an OCIParam parameter handle and setting type information in the OCIParam
using OCIAttrSet() calls.

coll_count (IN)
The count of elements in the collection. Pass 0 for a nested table (which is
unbounded).

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Related Topics
•

OCIAttrSet()
Sets the value of an attribute of a handle or a descriptor.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3 OCI Any Data Interface Functions
Lists and describes OCI Any Data interface functions.
Table 30-3 lists the Any Data Interface functions that are described in this section.
Table 30-3

Any Data Functions

Function

Purpose

OCIAnyDataAccess()

Retrieve the data value of an OCIAnyData

OCIAnyDataAttrGet()

Get the value of the attribute at the current
position in the OCIAnyData

OCIAnyDataAttrSet()

Set the attribute at the current position with
a given value

OCIAnyDataBeginCreate()

Allocate an OCIAnyData for the given
duration and initialize it with the type
information

OCIAnyDataCollAddElem()

Add the next collection element to the
collection attribute of the OCIAnyData at the
current attribute position

OCIAnyDataCollGetElem()

Access sequentially the elements in the
collection attribute at the current position in
the OCIAnyData

OCIAnyDataConvert()

Construct an OCIAnyData with the given
data value of the given type

OCIAnyDataDestroy()

Free an AnyData

OCIAnyDataEndCreate()

Mark the end of OCIAnyData creation

OCIAnyDataGetCurrAttrNum()

Return the current attribute number of the
OCIAnyData

OCIAnyDataGetType()

Get the type corresponding to an AnyData
value

OCIAnyDataIsNull()

Check if OCIAnyData is NULL

OCIAnyDataTypeCodeToSqlt()

Convert the OCITypeCode for an AnyData
value to the SQLT code that corresponds
to the representation of the value as
returned by the OCIAnyData API

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30.3.1 OCIAnyDataAccess()
Retrieve the data value of an OCIAnyData.
Purpose
The data value should be of the type with which the OCIAnyData was initialized. You can
use this call to access an entire OCIAnyData, which can be of type OCI_TYPECODE_OBJECT,
any of the collection types, or any of the built-in types.
Syntax
sword OCIAnyDataAccess ( OCISvcCtx
OCIError
OCIAnyData
OCITypeCode
OCIType
void
void
ub4

*svchp,
*errhp,
*sdata,
tc,
*inst_type,
*null_ind,
*data_value,
*length );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN)
Initialized pointer to an OCIAnyData.
tc (IN)
Typecode of the data value. This is used for type checking (with the initialization type
of the OCIAnyData).
inst_type (IN)
The OCIType of the data value (if it is not a primitive one). If the tc parameter is any of
the following types, then this parameter should be not NULL.
•

OCI_TYPECODE_OBJECT

•

OCI_TYPECODE_REF

•

OCI_TYPECODE_VARRAY

•

OCI_TYPECODE_TABLE

Otherwise, it could be NULL.
null_ind (OUT)
Indicates if the data_value is NULL. Pass an (OCIInd *) for all typecodes except
OCI_TYPECODE_OBJECT. The value returned is OCI_IND_NOTNULL if the value is not NULL,
and it is OCI_IND_NULL for a NULL value. If the typecode is OCI_TYPECODE_OBJECT, pass a
pointer to the indicator struct of the data_value as the argument here. See
OCIAnyDataAttrGet() for details.

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data_value (OUT)
The data value (is of the type with which the OCIAnyData was initialized). See
OCIAnyDataAttrGet() for the appropriate C type corresponding to each allowed
typecode and for a description of how memory allocation behavior depends on the
value passed for this parameter.
length (OUT)
Currently, this parameter is ignored. In the future, this may be used for certain
typecodes where the data representation itself does not give the length, in bytes,
implicitly.
Related Topics
•

OCIAnyDataAttrGet()
Gets the value of the attribute at the current position in the OCIAnyData.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.2 OCIAnyDataAttrGet()
Gets the value of the attribute at the current position in the OCIAnyData.
Purpose
Attribute values can be accessed sequentially.
Syntax
sword OCIAnyDataAttrGet ( OCISvcCtx
OCIError
OCIAnyData
OCITypeCode
OCIType
void
void
ub4
boolean

*svchp,
*errhp,
*sdata,
tc,
*attr_type,
*null_ind,
*attr_value,
*length,
is_any );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN/OUT)
Pointer to initialized type OCIAnyData.
tc (IN)
Typecode of the attribute. Type checking happens based on tc, attr_type, and the
type information in the OCIAnyData.

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attr_type (IN) [optional]
The attr_type parameter should give the type description of the referenced type (for
OCI_TYPECODE_REF) or the type description of the collection type (for
OCI_TYPECODE_VARRAY, OCI_TYPECODE_TABLE), or the type description of the object (for
OCI_TYPECODE_OBJECT). This parameter is not required for built-in typecodes.
null_ind (OUT)
Indicates if the attr_value is NULL. Pass (OCIInd *) in null_ind for all typecodes except
OCI_TYPECODE_OBJECT.
If the typecode is OCI_TYPECODE_OBJECT, pass a pointer (void **) in null_ind.
The indicator returned is OCI_IND_NOTNULL if the value is not NULL, and it is OCI_IND_NULL
for a NULL value.
attr_value (IN/OUT)
Value for the attribute.
length (IN/OUT)
Currently, this parameter is ignored. Pass 0 here. In the future, this may be used for
certain typecodes where the data representation itself does not give the length, in
bytes, implicitly.
is_any (IN)
Is attribute to be returned in the form of OCIAnyData?
Comments
You can use this call with an OCIAnyData of typecode OCI_TYPECODE_OBJECT only.
•

This call gets the value of the attribute at the current position in the OCIAnyData.

•

The tc parameter must match the type of the attribute at the current position;
otherwise, an error is returned.

•

The is_any parameter is applicable only when the typecode of the attribute is one
of these values:
–

OCI_TYPECODE_OBJECT

–

OCI_TYPECODE_VARRAY

–

OCI_TYPECODE_TABLE

If is_any is TRUE, then attr_value is returned in the form of OCIAnyData*.
•

You must allocate the memory for the attribute before calling the function. You can
allocate memory through OCIObjectNew(). For built-in types such as NUMBER and
VARCHAR, the attribute can be just a pointer to a stack variable. Table 30-4 lists the
available Oracle data types that can be used as object attribute types and the
corresponding types of the attribute value that should be passed.

Table 30-4

Data Types and Attribute Values

Data Types

attr_value

VARCHAR2, VARCHAR, CHAR

OCIString **

NUMBER, REAL, INT, FLOAT,
DECIMAL

OCINumber **

DATE

OCIDate **

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Table 30-4

(Cont.) Data Types and Attribute Values

Data Types

attr_value

TIMESTAMP

OCIDateTime **

TIMESTAMP WITH TIME ZONE

OCIDateTime **

TIMESTAMP WITH LOCAL TIME
ZONE

OCIDateTime **

INTERVAL YEAR TO MONTH

OCIInterval **

INTERVAL DAY TO SECOND

OCIInterval **

BLOB

OCILobLocator ** or OCIBlobLocator **

CLOB

OCILobLocator ** or OCIClobLocator *

BFILE

OCILobLocator **

REF

OCIRef **

RAW

OCIRaw **

VARRAY

OCIArray ** (or OCIAnyData * if is_any is TRUE)

TABLE

OCITable ** (or OCIAnyData * if is_any is TRUE)

OBJECT

void ** (or OCIAnyData * if is_any is TRUE)

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.3 OCIAnyDataAttrSet()
Sets the attribute at the current position with a given value.
Purpose
Sets the attribute at the current position with a given value.
Syntax
sword OCIAnyDataAttrSet ( OCISvcCtx
OCIError
OCIAnyData
OCITypeCode
OCIType
void
void
ub4
boolean

*svchp,
*errhp,
*sdata,
tc,
*attr_type,
*null_ind,
*attr_value,
length,
is_any );

Parameters
svchp (IN)
The OCI service context.

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errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN/OUT)
Initialized OCIAnyData.
tc (IN)
Typecode of the attribute. Type checking happens based on tc, attr_type, and the
type information in the OCIAnyData.
attr_type (IN) [optional]
The attr_type parameter gives the type description of the referenced type (for
OCI_TYPECODE_REF), the type description of the collection type (for OCI_TYPECODE_VARRAY,
OCI_TYPECODE_TABLE), and the type description of the object (for OCI_TYPECODE_OBJECT).
This parameter is not required for built-in typecodes or if OCI_TYPECODE_NONE is
specified.
null_ind (IN)
Indicates if the attr_value is NULL. Pass (OCIInd *) for all typecodes except
OCI_TYPECODE_OBJECT. The indicator should be OCI_IND_NOTNULL if the value is not NULL,
and it should be OCI_IND_NULL for a NULL value.
If the typecode is OCI_TYPECODE_OBJECT, pass a pointer to the indicator struct of the
attr_value as the argument here.
attr_value (IN)
Value for the attribute.
length (IN)
Currently, this parameter is ignored. Pass 0 here. In the future, this may be used for
certain typecodes where the data representation itself does not give the length
implicitly.
is_any (IN)
Is attribute in the form of OCIAnyData?
Comments
OCIAnyDataBeginCreate() creates an OCIAnyData with an empty skeleton instance. To fill
the attribute values, use OCIAnyDataAttrSet() (for OCI_TYPECODE_OBJECT) or
OCIAnyDataCollAddElem() (for the collection typecodes).

Attribute values must be set in order, from the first attribute to the last. The current
attribute number is remembered as the state maintained inside the OCIAnyData. Piecewise construction of embedded attributes and collection elements is not yet supported.
This call sets the attribute at the current position with attr_value. Once piece-wise
construction has started for an OCIAnyData instance, the OCIAnyDataConstruct() calls
can no longer be used.
The tc parameter must match the type of the attribute at the current position.
Otherwise, an error is returned.
If is_any is TRUE, then the attribute must be in the form of OCIAnyData*, and it is copied
into the enclosing OCIAnyData (data) without any conversion.
Table 30-5 lists the available data types that can be used as object attribute types and
the corresponding types of the attribute value that should be passed.

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Table 30-5

Data Types and Attribute Values

Data Types

attr_value

VARCHAR2, VARCHAR, CHAR

OCIString *

NUMBER, REAL, INT, FLOAT,
DECIMAL

OCINumber *

DATE

OCIDate *

TIMESTAMP

OCIDateTime *

TIMESTAMP WITH TIME ZONE

OCIDateTime *

TIMESTAMP WITH LOCAL TIME ZONE

OCIDateTime *

INTERVAL YEAR TO MONTH

OCIInterval *

INTERVAL DAY TO SECOND

OCIInterval *

BLOB

OCILobLocator * or OCIBlobLocator *

CLOB

OCILobLocator * or OCIClobLocator *

BFILE

OCILobLocator *

REF

OCIRef *

RAW

OCIRaw *

VARRAY

OCIArray * (or OCIAnyData * if is_any is TRUE)

TABLE

OCITable * (or OCIAnyData * if is_any is TRUE)

OBJECT

void * (or OCIAnyData * if is_any is TRUE)

Related Topics
•

OCIAnyDataBeginCreate()
Allocates an OCIAnyData for the given duration and initializes it with the type
information.

•

OCIAnyDataCollAddElem()
Adds the next collection element to the collection attribute of the OCIAnyData at the
current attribute position.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.4 OCIAnyDataBeginCreate()
Allocates an OCIAnyData for the given duration and initializes it with the type
information.
Purpose
Allocates an OCIAnyData for the given duration and initializes it with the type
information.
Syntax
sword OCIAnyDataBeginCreate ( OCISvcCtx
OCIError
OCITypeCode
OCIType

*svchp,
*errhp,
tc,
*type,

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OCIDuration
OCIAnyData

dur,
**sdata );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tc (IN)
Typecode corresponding to OCIAnyData. Can be a built-in typecode or a user-defined
type's typecode such as:
•

OCI_TYPECODE_OBJECT

•

OCI_TYPECODE_REF

•

OCI_TYPECODE_VARRAY

type (IN)
The type corresponding to OCIAnyData. If the typecode corresponds to a built-in type
(OCI_TYPECODE_NUMBER, and so on), this parameter can be NULL. It should be non-NULL
for user-defined types (OCI_TYPECODE_OBJECT, OCI_TYPECODE_REF, collection types, and so
on).
dur (IN)
Duration for which OCIAnyData is allocated. It is one of these:
•

A user duration that was previously created. It can be created by using .

•

A predefined duration, such as OCI_DURATION_SESSION.

sdata (OUT)
Initialized OCIAnyData. If (*sdata) is not NULL at the beginning of the call, the memory
could be reused instead of reallocating space for OCIAnyData.
Therefore, do not pass an uninitialized pointer here.
Comments
OCIAnyDataBeginCreate() creates an OCIAnyData with an empty skeleton instance. To fill
in the attribute values, use OCIAnyDataAttrSet() for OCI_TYPECODE_OBJECT or
OCIAnyDataCollAddElem() for the collection typecodes.

Attribute values must be set in order. They must be set from the first attribute to the
last. The current attribute number is remembered as state maintained inside the
OCIAnyData. Piece-wise construction of embedded attributes and collection elements is
not yet supported.
For performance reasons, OCIAnyData ends up pointing to the OCIType parameter
passed in. You must ensure that the OCIType lives longer (has an allocation duration >=
the duration of OCIAnyData, if the OCIType is a transient one, or has an allocation or pin
duration >= the duration of OCIAnyData, if the OCIType is a persistent one).
Related Topics
•

OCIDurationBegin()
Starts a user duration.

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•

OCIAnyDataAttrSet()
Sets the attribute at the current position with a given value.

•

OCIAnyDataCollAddElem()
Adds the next collection element to the collection attribute of the OCIAnyData at the
current attribute position.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.5 OCIAnyDataCollAddElem()
Adds the next collection element to the collection attribute of the OCIAnyData at the
current attribute position.
Purpose
If the OCIAnyData is of a collection type, then there is no notion of attribute position and
this call adds the next collection element.
Syntax
sword OCIAnyDataCollAddElem ( OCISvcCtx
OCIError
OCIAnyData
OCITypeCode
OCIType
void
void
ub4
boolean
boolean

*svchp,
*errhp,
*sdata,
collelem_tc,
*collelem_type,
*null_ind,
*elem_value,
length,
is_any,
last_elem );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN/OUT)
Initialized OCIAnyData.
collelem_tc (IN)
The typecode of the collection element to be added. Type checking happens based
on collelem_tc, collelem_type and the type information in the OCIAnyData.
collelem_type (IN) [optional]
The collelem_type parameter gives the type description of the referenced type (for
OCI_TYPECODE_REF), the type description of the collection type (for
OCI_TYPECODE_NAMEDCOLLECTION), and the type description of the object (for
OCI_TYPECODE_OBJECT).
This parameter is not required for built-in typecodes.

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null_ind (IN)
Indicates if the elem_value is NULL. Pass an (OCIInd *) for all typecodes except
OCI_TYPECODE_OBJECT. The indicator should be OCI_IND_NOTNULL if the value is not NULL,
and it should be OCI_IND_NULL for a NULL value.
If the typecode is OCI_TYPECODE_OBJECT, pass a pointer to the indicator struct of the
elem_value as the argument here.
elem_value (IN)
Value for the collection element.
length (IN)
Length of the collection element.
is_any (IN)
Is the attribute in the form of OCIAnyData?
last_elem (IN)
Is the element being added the last in the collection?
Comments
This call can be invoked for an OCIAnyData of type OCI_TYPECODE_OBJECT or of any of the
collection types. Once piece-wise construction has started for an OCIAnyData instance,
the OCIAnyDataConstruct() calls can no longer be used.
As in OCIAnyDataAttrSet(), is_any is applicable only if the collelem_tc is that of
typecode OCI_TYPECODE_OBJECT or a collection typecode. If is_any is TRUE, the attribute
should be in the form of OCIAnyData *.
If the element being added is the last element in the collection, last_elem should be set
to TRUE.
To add a NULL element, the NULL indicator (null_ind) should be set to OCI_IND_NULL, in
which case all other arguments are ignored. Otherwise, null_ind must be set to
OCI_IND_NOTNULL.
See OCIAnyDataAttrSet() for the type of attribute to be passed in for all the possible
types of the collection elements.
Related Topics
•

OCIAnyDataAttrSet()
Sets the attribute at the current position with a given value.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.6 OCIAnyDataCollGetElem()
Accesses sequentially the elements in the collection attribute at the current position in
the OCIAnyData.
Purpose
Accesses sequentially the elements in the collection attribute at the current position in
the OCIAnyData.

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Syntax
sword OCIAnyDataCollGetElem ( OCISvcCtx
OCIError
OCIAnyData
OCITypeCode
OCIType
void
void
ub4
boolean

*svchp,
*errhp,
*sdata,
collelem_tc,
*collelem_type,
*null_ind,
*collelem_value,
*length,
is_any );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN/OUT)
Initialized OCIAnyData.
collelem_tc (IN)
The typecode of the collection element to be retrieved. Type checking happens based
on collelem_tc, collelem_type and the type information in the OCIAnyData.
collelem_type (IN) [optional]
The collelem_type parameter gives the type description of the referenced type (for
OCI_TYPECODE_REF), the type description of the collection type (for
OCI_TYPECODE_NAMEDCOLLECTION), and the type description of the object (for
OCI_TYPECODE_OBJECT).
This parameter is not required for built-in typecodes.
null_ind (OUT)
Indicates if the collelem_value is NULL. Pass an (OCIInd *) for all typecodes except
OCI_TYPECODE_OBJECT. The indicator should be OCI_IND_NOTNULL if the value is not NULL,
and it should be OCI_IND_NULL for a NULL value.
If the typecode is OCI_TYPECODE_OBJECT, pass a pointer (void **) to the indicator struct
of the collelem_value as the argument here.
collelem_value (IN/OUT)
Value for the collection element.
length (IN/OUT)
Length of the collection element. Currently ignored. Set to 0 on input.
is_any (IN)
Is attr_value to be returned in the form of OCIAnyData?
Comments
The OCIAnyData data can also correspond to a top-level collection. If the OCIAnyData is
of type OCI_TYPECODE_OBJECT, the attribute at the current position must be a collection of
the appropriate type. Otherwise, an error is returned.

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As for OCIAnyDataAttrGet(), the is_any parameter is applicable only if the collelem_tc
typecode is OCI_TYPECODE_OBJECT. If is_any is TRUE, the attr_value is in the form of
OCIAnyData *.
This call returns OCI_NO_DATA when the end of the collection has been reached. It
returns OCI_SUCCESS upon success and OCI_ERROR upon error.
See OCIAnyDataAttrGet() for the type of attribute to be passed in for all the possible
types of the collection elements.
Related Topics
•

OCIAnyDataAttrGet()
Gets the value of the attribute at the current position in the OCIAnyData.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.7 OCIAnyDataConvert()
Constructs an OCIAnyData with the given data value that is of the given type.
Purpose
You can use this call to construct an entire OCIAnyData, which could be of type
OCI_TYPECODE_OBJECT, any of the collection types, or any of the built-in types.
Syntax
sword OCIAnyDataConvert ( OCISvcCtx
OCIError
OCITypeCode
OCIType
OCIDuration
void
void
ub4
OCIAnyData

*svchp,
*errhp,
tc,
*inst_type,
dur,
*null_ind,
*data_value,
length,
**sdata );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
tc (IN)
Typecode of the data value. Can be a built-in typecode or a user-defined type's
typecode (such as OCI_TYPECODE_OBJECT, OCI_TYPECODE_REF, or OCI_TYPECODE_VARRAY).
If (*sdata) is not NULL and it represents a skeleton instance returned during the
OCIAnyDataSetAddInstance(), the tc and the inst_type parameters are optional here.
This is because the type information for such a skeleton instance is known. If the tc
and inst_type parameters are provided for this situation, they are used only for typechecking purposes.

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inst_type (IN)
Type corresponding to the OCIAnyData. If the typecode corresponds to a built-in type
(OCI_TYPECODE_NUMBER, and so on), this parameter can be NULL. It should not be NULL for
user-defined types (OCI_TYPECODE_OBJECT, OCI_TYPECODE_REF, or collection types).
dur (IN)
Duration for which the OCIAnyData is allocated. It is one of these:
•

A user duration that was previously created. It can be created by using
OCIDurationBegin().

•

A predefined duration, such as OCI_DURATION_SESSION.

null_ind
Indicates if data_value is NULL. Pass an (OCIInd *) for all typecodes except
OCI_TYPECODE_OBJECT. The indicator is OCI_IND_NOTNULL if the value is not NULL, and it is
OCI_IND_NULL for a NULL value.
If the typecode is OCI_TYPECODE_OBJECT, pass a pointer to the indicator struct of the
data_value as the argument here.
data_value (IN)
The data value (should be of the type with which the OCIAnyData was initialized). See
OCIAnyDataAttrSet() for the appropriate C type corresponding to each allowed
typecode.
length (IN)
Currently, this parameter is ignored. Pass 0 here. In the future, this may be used for
certain typecodes where the data representation itself does not give the length
implicitly.
sdata (IN/OUT)
Initialized OCIAnyData. If (*sdata) is not NULL at the beginning of the call, the memory
could be reused instead of reallocating space for OCIAnyData.
Therefore, do not pass an uninitialized pointer here.
If (*sdata) represents a skeleton instance returned during an
OCIAnyDataSetAddInstance() call, the tc and inst_type parameters are used for type
checking, if necessary.
Comments
For performance reasons, OCIAnyData pointer ends up pointing to the passed in OCIType
parameter. You must ensure that the OCIType lives longer (has an allocation duration
>= the duration of OCIAnyData, if the OCIType is a transient one, or has an allocation or
pin duration >= the duration of OCIAnyData, if the OCIType is a persistent one).
Related Topics
•

OCIAnyDataSetAddInstance()
Adds a new skeleton instance to the OCIAnyDataSet and sets all the attributes of the
instance to NULL.

•

OCIAnyDataAttrSet()
Sets the attribute at the current position with a given value.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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30.3.8 OCIAnyDataDestroy()
Free an OCIAnyData.
Purpose
Frees an OCIAnyData.
Syntax
sword OCIAnyDataDestroy ( OCISvcCtx
OCIError
OCIAnyData

*svchp,
*errhp,
*sdata );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN/OUT)
Pointer to a type of OCIAnyData to be freed.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.9 OCIAnyDataEndCreate()
Marks the end of OCIAnyData creation.
Purpose
It should be called after initializing all attributes of its instances with suitable values.
This call is valid only if OCIAnyDataBeginCreate() was called earlier for the OCIAnyData.
Syntax
sword OCIAnyDataEndCreate ( OCISvcCtx
OCIError
OCIAnyData

*svchp,
*errhp,
*data );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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data (IN/OUT)
Initialized OCIAnyData.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.10 OCIAnyDataGetCurrAttrNum()
Returns the current attribute number of OCIAnyData.
Purpose
If OCIAnyData is being constructed, this function refers to the current attribute that is
being set. Otherwise, if OCIAnyData is being accessed, this function refers to the
attribute that is being accessed.
Syntax
sword OCIAnyDataGetCurrAttrNum( OCISvcCtx
OCIError
OCIAnyData
ub4

*svchp,
*errhp,
*sdata,
*attrnum );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
sdata (IN)
Initialized OCIAnyData.
attrnum (OUT)
The attribute number.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.11 OCIAnyDataGetType()
Gets the type corresponding to an OCIAnyData value.
Purpose
It returns the actual pointer to the type maintained inside an OCIAnyData. No copying is
done for performance reasons. Do not use this type after the OCIAnyData is freed (or its
duration ends).

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Syntax
sword OCIAnyDataGetType( OCISvcCtx
OCIError
OCIAnyData
OCITypeCode
OCIType

*svchp,
*errhp,
*data,
*tc,
**type );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
data (IN)
Initialized OCIAnyData.
tc (OUT)
The typecode corresponding to the OCIAnyData.
type (OUT)
The type corresponding to the OCIAnyData. This is NULL if the OCIAnyData corresponds to
a built-in type.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.12 OCIAnyDataIsNull()
Checks if the content of the type within the OCIAnyData is NULL.
Purpose
Checks if the content of the type within the OCIAnyData is NULL.
Syntax
sword OCIAnyDataIsNull ( OCISvcCtx
*svchp,
OCIError
*errhp,
const OCIAnyData *sdata,
boolean
*isNull) ;

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err and this function returns
OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

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sdata (IN)
OCIAnyData to be checked.

isNull (IN/OUT)
TRUE if NULL; otherwise, FALSE.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.3.13 OCIAnyDataTypeCodeToSqlt()
Converts the OCITypeCode for an AnyData value to the SQLT code that corresponds to
the representation of the value as returned by the OCIAnyData API.
Purpose
Converts the OCITypeCode for an OCIAnyData value to the SQLT code that corresponds
to the representation of the value as returned by the OCIAnyData API.
Syntax
sword OCIAnyDataTypeCodeToSqlt ( OCIError
OCITypeCode
ub1
ub1

*errhp,
tc,
*sqltcode,
*csfrm) ;

Parameters
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in errhp, and this function
returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().
tc (IN)
OCITypeCode corresponding to the AnyData value.

sqltcode (OUT)
SQLT code corresponding to the user format of the typecode.
csfrm (OUT)
Charset form corresponding to the user format of the typecode. Meaningful only for
character types. Returns SQLCS_IMPLICIT or SQLCS_NCHAR (for NCHAR types).
Comments
This function converts OCI_TYPECODE_CHAR and OCI_TYPECODE_VARCHAR2 to SQLT_VST (which
corresponds to the OCIString mapping) with a charset form of SQLCS_IMPLICIT.
OCI_TYPECODE_NVARCHAR2 also returns SQLT_VST (OCIString mapping is used by the
OCIAnyData API) with a charset form of SQLCS_NCHAR.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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•

NCHAR Typecodes for OCIAnyData Functions
The function OCIAnyDataTypeCodeToSqlt() converts the OCITypeCode for an
OCIAnyData value to the SQLT code that corresponds to the representation of the
value as returned by the OCIAnyData API.

30.4 OCI Any Data Set Interface Functions
Lists and describes OCI Any Data set interface functions.
Table 30-6 lists the Any Data Set Interface functions that are described in this section.
Table 30-6

Any Data Set Functions

Function

Purpose

OCIAnyDataSetAddInstance()

Add a new skeleton instance to the
OCIAnyDataSet and set all the attributes of
the instance to NULL

OCIAnyDataSetBeginCreate()

Allocate an OCIAnyDataSet for the given
duration and initialize it with the type
information

OCIAnyDataSetDestroy()

Free the OCIAnyDataSet

OCIAnyDataSetEndCreate()

Mark the end of OCIAnyDataSet creation

OCIAnyDataSetGetCount()

Get the number of instances in the
OCIAnyDataSet

OCIAnyDataSetGetInstance()

Return the OCIAnyData corresponding to an
instance at the current position and update
the current position

OCIAnyDataSetGetType()

Get the type corresponding to an
OCIAnyDataSet

30.4.1 OCIAnyDataSetAddInstance()
Adds a new skeleton instance to the OCIAnyDataSet and sets all the attributes of the
instance to NULL.
Purpose
Adds a new skeleton instance to the OCIAnyDataSet and sets all the attributes of the
instance to NULL.
Syntax
sword OCIAnyDataSetAddInstance ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCIAnyDataSet *data_set,
OCIAnyData
**data );

Parameters
svchp (IN)
The OCI service context.

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errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
data_set (IN/OUT)
OCIAnyDataSet to which a new instance is added.

data (IN/OUT)
OCIAnyData corresponding to the newly added instance. If (*data) is NULL, a new
OCIAnyData is allocated for the same duration as the OCIAnyDataSet. If (*data) is not
NULL, it is reused. This OCIAnyData can be subsequently constructed using the
OCIAnyDataConvert() call, or it can be constructed piece-wise using the
OCIAnyDataAttrSet() or the OCIAnyDataCollAddElem() calls.

Comments
This call returns this skeleton instance through the OCIAnyData parameter that can be
constructed subsequently by invoking the OCIAnyData API.

Note:
The old value is not destroyed. You must destroy the old value pointed to by
(*data) and set (*data) to a NULL pointer before beginning to make a
sequence of these calls. No deep copying (of OCIType information or of the
data part) is done in the returned OCIAnyData. This OCIAnyData cannot be used
beyond the allocation duration of the OCIAnyDataSet (it is like a reference into
the OCIAnyDataSet). The returned OCIAnyData can be reused on subsequent
calls to this function, to sequentially add new data instances to the
OCIAnyDataSet.

Related Topics
•

OCIAnyDataConvert()
Constructs an OCIAnyData with the given data value that is of the given type.

•

OCIAnyDataAttrSet()
Sets the attribute at the current position with a given value.

•

OCIAnyDataCollAddElem()
Adds the next collection element to the collection attribute of the OCIAnyData at the
current attribute position.

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.4.2 OCIAnyDataSetBeginCreate()
Allocates an OCIAnyDataSet for the given duration and initializes it with the type
information.
Purpose
The OCIAnyDataSet can hold multiple instances of the given type.

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Syntax
sword OCIAnyDataSetBeginCreate ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCITypeCode
typecode,
const OCIType *type,
OCIDuration
dur,
OCIAnyDataSet **data_set );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().
typecode (IN)
Typecode corresponding to the OCIAnyDataSet.
type (IN)
Type corresponding to the OCIAnyDataSet. If the typecode corresponds to a built-in
type, such as OCI_TYPECODE_NUMBER, this parameter can be NULL. It should be non-NULL
for user-defined types, such as OCI_TYPECODE_OBJECT, OCI_TYPECODE_REF, and collection
types.
dur (IN)
Duration for which OCIAnyDataSet is allocated. It is one of these:
•

A user duration that was previously created. It can be created by using
OCIDurationBegin().

•

A predefined duration, such as OCI_DURATION_SESSION.

data_set (OUT)
Initialized OCIAnyDataSet.
Comments
For performance reasons, the OCIAnyDataSet ends up pointing to the OCIType parameter
passed in. You must ensure that the OCIType lives longer (has an allocation duration >=
the duration of the OCIAnyData if the OCIType is a transient one, or has allocation or pin
duration >= the duration of the OCIAnyData, if the OCIType is a persistent one).
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.4.3 OCIAnyDataSetDestroy()
Frees the OCIAnyDataSet.
Purpose
Frees the OCIAnyDataSet.

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Syntax
sword OCIAnyDataSetDestroy ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCIAnyDataSet *data_set );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCI_ERROR.
data_set (IN/OUT)
OCIAnyDataSet to be freed.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.4.4 OCIAnyDataSetEndCreate()
Marks the end of OCIAnyDataSet creation.
Purpose
This function should be called after constructing all of its instances.
Syntax
sword OCIAnyDataSetEndCreate ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCIAnyDataSet *data_set );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCI_ERROR.
data_set (IN/OUT)
Initialized OCIAnyDataSet.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

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30.4.5 OCIAnyDataSetGetCount()
Gets the number of instances in the OCIAnyDataSet.
Purpose
Gets the number of instances in the OCIAnyDataSet.
Syntax
sword OCIAnyDataSetGetCount( OCISvcCtx
OCIError
OCIAnyDataSet
ub4

*svchp,
*errhp,
*data_set,
*count );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCI_ERROR.
data_set (IN/OUT)
A well-formed OCIAnyDataSet.
count (OUT)
Number of instances in OCIAnyDataSet.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.4.6 OCIAnyDataSetGetInstance()
Returns the OCIAnyData corresponding to an instance at the current position and
updates the current position.
Purpose
Returns the OCIAnyData corresponding to an instance at the current position and
updates the current position.
Syntax
sword OCIAnyDataSetGetInstance ( OCISvcCtx
OCIError
OCIAnyDataSet
OCIAnyData

*svchp,
*errhp,
*data_set,
**data );

Parameters
svchp (IN)
The OCI service context.

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errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCI_ERROR.
data_set (IN/OUT)
A well-formed OCIAnyDataSet.
data (IN/OUT)
OCIAnyData corresponding to the instance. If (*data) is NULL, a new OCIAnyData is
allocated for same duration as the OCIAnyDataSet. If (*data) is not NULL, it is reused.

Comments
Only sequential access to the instances in an OCIAnyDataSet is allowed. This call
returns the OCIAnyData corresponding to an instance at the current position and
updates the current position. Subsequently, the OCIAnyData access routines can be
used to access the instance.
Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30.4.7 OCIAnyDataSetGetType()
Gets the type corresponding to an OCIAnyDataSet.
Purpose
Gets the type corresponding to an OCIAnyDataSet.
Syntax
sword OCIAnyDataSetGetType ( OCISvcCtx
OCIError
OCIAnyDataSet
OCITypeCode
OCIType

*svchp,
*errhp,
*data_set,
*tc,
**type );

Parameters
svchp (IN)
The OCI service context.
errhp (IN/OUT)
The OCI error handle. If there is an error, it is recorded in err, and this function
returns OCI_ERROR. Obtain diagnostic information by calling OCI_ERROR.
data_set (IN)
Initialized OCIAnyDataSet.
tc (OUT)
The typecode corresponding to the type of the OCIAnyDataSet.
type (OUT)
The type corresponding to the OCIAnyDataSet. This is NULL if the OCIAnyData
corresponds to a built-in type.

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Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

30-30

31
OCI Globalization Support Functions
This chapter describes the OCI globalization support functions.
This chapter contains these topics:
•

Introduction to Globalization Support in OCI

•

OCI Locale Functions

•

OCI Locale-Mapping Function

•

OCI String Manipulation Functions

•

OCI Character Classification Functions

•

OCI Character Set Conversion Functions

•

OCI Messaging Functions

31.1 Introduction to Globalization Support in OCI
This section describes the globalization support functions in detail.

See Also:
Oracle Database Globalization Support Guide

31.1.1 Conventions for OCI Functions
Describes the conventions for OCI functions.
The entries for each function may also contain the following information:
•

Returns — The values returned. The standard return values have the following
meanings as described in the following table.

Table 31-1

Function Return Values

Return Value

Meaning

OCI_SUCCESS

The operation succeeded.

OCI_ERROR

The operation failed. The specific error can be
retrieved by calling OCIErrorGet() on the error handle
passed to the function.

OCI_INVALID_HANDLE

The OCI handle passed to the function is invalid.

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See Also:
•

Conventions for OCI Functionsfor the conventions used in describing
each function

•

Error Handling in OCI for more information about return codes and error
handling

31.2 OCI Locale Functions
Lists and describes OCI Locale Functions.
Table 31-2 lists the OCI locale functions that are described in this section.
An Oracle locale consists of language, territory, and character set definitions. The
locale determines conventions such as day and month names, and date, time,
number, and currency formats. A globalized application obeys a user's locale setting
and cultural conventions. For example, when the locale is set to German, users expect
to see day and month names in German.
Table 31-2

OCI Locale Functions

Function

Purpose

OCINlsCharSetIdToName()

Return the Oracle Database character
set name from the specified character
set ID

OCINlsCharSetNameToId()

Return the Oracle Database character
set ID for the specified Oracle Database
character set name

OCINlsEnvironmentVariableGet()

Return the character set ID from
NLS_LANG or the national character set
ID from NLS_NCHAR

OCINlsGetInfo()

Copy locale information from an OCI
environment or user session handle into
an array pointed to by the destination
buffer within a specified size

OCINlsNumericInfoGet()

Copy numeric language information
from the OCI environment or user
session handle into an output number
variable

31.2.1 OCINlsCharSetIdToName()
Returns the Oracle Database character set name from the specified character set ID.
Purpose
Returns the Oracle Database character set name from the specified character set ID.

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Syntax
sword OCINlsCharSetIdToName ( void
OraText
size_t
ub2

*hndl,
*buf,
buflen
id );

Parameters
hndl (IN/OUT)
OCI environment or user session handle. If the handle is invalid, then the function
returns OCI_INVALID_HANDLE.
buf (OUT)
Points to the destination buffer. If the function returns OCI_SUCCESS, then the parameter
contains a NULL-terminated string for the character set name.
buflen (IN)
The size of the destination buffer. The recommended size is OCI_NLS_MAXBUFSZ to
guarantee storage for an Oracle Database character set name. If the size of the
destination buffer is smaller than the length of the character set name, then the
function returns OCI_ERROR.
id (IN)
Oracle Database character set ID.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

31.2.2 OCINlsCharSetNameToId()
Returns the Oracle Database character set ID for the specified Oracle Database
character set name.
Purpose
Returns the Oracle Database character set ID for the specified Oracle Database
character set name.
Syntax
ub2 OCINlsCharSetNameToId ( void
const OraText

*hndl,
*name );

Parameters
hndl (IN/OUT)
OCI environment or user session handle. If the handle is invalid, then the function
returns zero.
name (IN)
Pointer to a NULL-terminated Oracle Database character set name. If the character set
name is invalid, then the function returns zero.

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Returns
Character set ID if the specified character set name and the OCI handle are valid.
Otherwise, it returns 0.

31.2.3 OCINlsEnvironmentVariableGet()
Returns the character set ID from NLS_LANG or the national character set ID from
NLS_NCHAR.
Purpose
Returns the character set ID from NLS_LANG or the national character set ID from
NLS_NCHAR.
Syntax
sword OCINlsEnvironmentVariableGet ( void
size_t
ub2
ub2
size_t

*val,
size,
item,
charset,
*rsize );

Parameters
val (IN/OUT)
Returns a value of a globalization support environment variable, such as the NLS_LANG
character set ID or the NLS_NCHAR character set ID.
size (IN)
Specifies the size of the given output value, which is applicable only to string data.
The maximum length for each piece of information is OCI_NLS_MAXBUFSZ bytes. For
numeric data, this argument is ignored.
item (IN)
Specifies one of these values to get from the globalization support environment
variable:
•

OCI_NLS_CHARSET_ID: NLS_LANG character set ID in ub2 data type; if NLS_LANG is not

set, the default character set ID is returned (ASCII).
•

OCI_NLS_NCHARSET_ID: NLS_NCHAR character set ID in ub2 data type; if NLS_NCHAR is not
set, the value of OCI_NLS_CHARSET_ID is returned instead.

charset (IN)
Specifies the character set ID for retrieved string data. If it is 0, then the NLS_LANG value
is used. OCI_UTF16ID is a valid value for this argument. For numeric data, this
argument is ignored.
rsize (OUT)
The length of the return value in bytes.
Comments
To allow for future enhancements of this function (to retrieve other values from
environment variables) the data type of the output val is a pointer to void. String data
is not terminated by NULL.

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Note that the function does not take an environment handle, so the character set ID
and the national character set ID that it returns are the values specified in NLS_LANG and
NLS_NCHAR, instead of the values saved in the OCI environment handle. To get the
character set IDs used by the OCI environment handle, call OCIAttrGet() for
OCI_ATTR_ENV_CHARSET_ID and OCI_ATTR_ENV_NCHARSET_ID, respectively.
Returns
OCI_SUCCESS; or OCI_ERROR.

Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.2.4 OCINlsGetInfo()
Copy locale information from an OCI environment or user session handle into an array
pointed to by the destination buffer within a specified size.
Purpose
Obtains locale information from an OCI environment or user session handle to an
array pointed to by the destination buffer within a specified size.
Syntax
sword OCINlsGetInfo ( void
OCIError
OraText
size_t
ub2

*hndl,
*errhp,
*buf,
buflen,
item );

Parameters
hndl (IN/OUT)
The OCI environment or user session handle initialized in object mode.
errhp (IN/OUT)
The OCI error handle. If there is an error, then it is recorded in errhp, and the function
returns a NULL pointer. Diagnostic information can be obtained by calling
OCIErrorGet().
buf (OUT)
Pointer to the destination buffer. Returned strings are terminated by a NULL character.
buflen (IN)
The size of the destination buffer. The maximum length for each piece of information
is OCI_NLS_MAXBUFSZ bytes.
OCI_NLS_MAXBUFSIZE: When calling OCINlsGetInfo(), you must allocate the buffer to store
the returned information. The buffer size depends on which item you are querying and
what encoding you are using to store the information. Developers should not need to
know how many bytes it takes to store January in Japanese using JA16SJIS encoding.
The OCI_NLS_MAXBUFSZ attribute guarantees that the buffer is big enough to hold the
largest item returned by OCINlsGetInfo().

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item (IN)
Specifies which item in the OCI environment handle to return. It can be one of these
values:
OCI_NLS_DAYNAME1: Native name for Monday
OCI_NLS_DAYNAME2: Native name for Tuesday
OCI_NLS_DAYNAME3: Native name for Wednesday
OCI_NLS_DAYNAME4: Native name for Thursday
OCI_NLS_DAYNAME5: Native name for Friday
OCI_NLS_DAYNAME6: Native name for Saturday
OCI_NLS_DAYNAME7: Native name for Sunday
OCI_NLS_ABDAYNAME1: Native abbreviated name for Monday
OCI_NLS_ABDAYNAME2: Native abbreviated name for Tuesday
OCI_NLS_ABDAYNAME3: Native abbreviated name for Wednesday
OCI_NLS_ABDAYNAME4: Native abbreviated name for Thursday
OCI_NLS_ABDAYNAME5: Native abbreviated name for Friday
OCI_NLS_ABDAYNAME6: Native abbreviated name for Saturday
OCI_NLS_ABDAYNAME7: Native abbreviated name for Sunday
OCI_NLS_MONTHNAME1: Native name for January
OCI_NLS_MONTHNAME2: Native name for February
OCI_NLS_MONTHNAME3: Native name for March
OCI_NLS_MONTHNAME4: Native name for April
OCI_NLS_MONTHNAME5: Native name for May
OCI_NLS_MONTHNAME6: Native name for June
OCI_NLS_MONTHNAME7: Native name for July
OCI_NLS_MONTHNAME8: Native name for August
OCI_NLS_MONTHNAME9: Native name for September
OCI_NLS_MONTHNAME10: Native name for October
OCI_NLS_MONTHNAME11: Native name for November
OCI_NLS_MONTHNAME12: Native name for December
OCI_NLS_ABMONTHNAME1: Native abbreviated name for January
OCI_NLS_ABMONTHNAME2: Native abbreviated name for February
OCI_NLS_ABMONTHNAME3: Native abbreviated name for March
OCI_NLS_ABMONTHNAME4: Native abbreviated name for April
OCI_NLS_ABMONTHNAME5: Native abbreviated name for May
OCI_NLS_ABMONTHNAME6: Native abbreviated name for June
OCI_NLS_ABMONTHNAME7: Native abbreviated name for July
OCI_NLS_ABMONTHNAME8: Native abbreviated name for August
OCI_NLS_ABMONTHNAME9: Native abbreviated name for September
OCI_NLS_ABMONTHNAME10: Native abbreviated name for October
OCI_NLS_ABMONTHNAME11: Native abbreviated name for November
OCI_NLS_ABMONTHNAME12: Native abbreviated name for December
OCI_NLS_YES: Native string for affirmative response
OCI_NLS_NO: Native negative response
OCI_NLS_AM: Native equivalent string of AM
OCI_NLS_PM: Native equivalent string of PM
OCI_NLS_AD: Native equivalent string of AD
OCI_NLS_BC: Native equivalent string of BC

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OCI_NLS_DECIMAL: Decimal character
OCI_NLS_GROUP: Group separator
OCI_NLS_DEBIT: Native symbol of debit
OCI_NLS_CREDIT: Native symbol of credit
OCI_NLS_DATEFORMAT: Oracle Database date format
OCI_NLS_INT_CURRENCY: International currency symbol
OCI_NLS_DUAL_CURRENCY: Dual currency symbol
OCI_NLS_LOC_CURRENCY: Locale currency symbol
OCI_NLS_LANGUAGE: Language name
OCI_NLS_ABLANGUAGE: Abbreviation for language name
OCI_NLS_TERRITORY: Territory name
OCI_NLS_CHARACTER_SET: Character set name
OCI_NLS_LINGUISTIC_NAME: Linguistic sort name
OCI_NLS_CALENDAR: Calendar name
OCI_NLS_WRITING_DIR: Language writing direction
OCI_NLS_ABTERRITORY: Territory abbreviation
OCI_NLS_DDATEFORMAT: Oracle Database default date format
OCI_NLS_DTIMEFORMAT: Oracle Database default time format
OCI_NLS_SFDATEFORMAT: Local date format
OCI_NLS_SFTIMEFORMAT: Local time format
OCI_NLS_NUMGROUPING: Number grouping fields
OCI_NLS_LISTSEP: List separator
OCI_NLS_MONDECIMAL: Monetary decimal character
OCI_NLS_MONGROUP: Monetary group separator
OCI_NLS_MONGROUPING: Monetary grouping fields
OCI_NLS_INT_CURRENCYSEP: International currency separator

Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

31.2.5 OCINlsNumericInfoGet()
Copy numeric language information from the OCI environment or user session handle
into an output number variable.
Purpose
Obtains numeric language information from the OCI environment or user session
handle and puts it into an output number variable.
Syntax
sword OCINlsNumericInfoGet ( void
OCIError
sb4
ub2

*hndl,
*errhp,
*val,
item );

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Parameters
hndl (IN/OUT)
The OCI environment or user session handle. If the handle is invalid, it returns
OCI_INVALID_HANDLE.
errhp (IN/OUT)
The OCI error handle. If there is an error, then it is recorded in errhp, and the function
returns a NULL pointer. Diagnostic information can be obtained by calling
OCIErrorGet().
val (OUT)
Pointer to the output number variable. If the function returns OCI_SUCCESS, then the
parameter contains the requested globalization support numeric information.
item (IN)
It specifies which item to get from the OCI environment handle and can be one of
following values:
•

OCI_NLS_CHARSET_MAXBYTESZ: Maximum character byte size for OCI environment or

session handle character set
•

OCI_NLS_CHARSET_FIXEDWIDTH: Character byte size for fixed-width character set; 0 for

variable-width character set
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

31.3 OCI Locale-Mapping Function
Lists and describes OCI locale-mapping functions.
Table 31-3 lists an OCI locale-mapping function that is described in this section.
The OCI locale-mapping function performs name mapping to and from Oracle
Database, Internet Assigned Numbers Authority (IANA), and International
Organization for Standardization (ISO) names for character set names, language
names, and territory names.
Table 31-3

OCI Locale-Mapping Function

Function

Purpose

OCINlsNameMap()

Map Oracle Database character set names, language names, and territory
names to and from Internet Assigned Numbers Authority (IANA) and
International Organization for Standardization (ISO) names

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31.3.1 OCINlsNameMap()
Maps Oracle Database character set names, language names, and territory names to
and from Internet Assigned Numbers Authority (IANA) and International Organization
for Standardization (ISO) names.
Purpose
Maps Oracle Database character set names, language names, and territory names to
and from Internet Assigned Numbers Authority (IANA) and International Organization
for Standardization (ISO) names.
Syntax
sword OCINlsNameMap ( void
OraText
size_t
const OraText
uword

*hndl,
*buf,
buflen,
*srcbuf,
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle. If the handle is invalid, then the function
returns OCI_INVALID_HANDLE.
buf (OUT)
Points to the destination buffer. If the function returns OCI_SUCCESS, then the parameter
contains a NULL-terminated string for the requested name.
buflen (IN)
The size of the destination buffer. The recommended size is OCI_NLS_MAXBUFSZ to
guarantee storage of a globalization support name. If the size of the destination buffer
is smaller than the length of the name, then the function returns OCI_ERROR.
srcbuf (IN)
Pointer to a NULL-terminated globalization support name. If it is not a valid name, then
the function returns OCI_ERROR.
flag (IN)
It specifies the direction of the name mapping and can take the following values:
OCI_NLS_CS_IANA_TO_ORA: Map character set name from IANA to Oracle Database
OCI_NLS_CS_ORA_TO_IANA: Map character set name from Oracle Database to IANA
OCI_NLS_LANG_ISO_TO_ORA: Map language name from ISO to Oracle Database
OCI_NLS_LANG_ORA_TO_ISO: Map language name from Oracle Database to ISO
OCI_NLS_LOCALE_A2_ISO_TO_ORA: Map locale name from A2 ISO to Oracle Database
OCI_NLS_LOCALE_ORA_TO_A2_ISO: Map locale name from Oracle Database to A2 ISO
OCI_NLS_TERR_ISO_TO_ORA: Map territory name from ISO to Oracle Database
OCI_NLS_TERR_ORA_TO_ISO: Map territory name from Oracle Database to ISO
OCI_NLS_TERR_ISO3_TO_ORA: Map territory name from 3-letter ISO abbreviation to

Oracle Database
OCI_NLS_TERR_ORA_TO_ISO3: Map territory name from Oracle Database to 3-letter ISO

abbreviation

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Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

31.4 OCI String Manipulation Functions
Lists and describes OCI string manipulation functions.
Two types of data structures are supported for string manipulation:
•

Multibyte strings

•

Wide-character strings

Multibyte strings are encoded in native Oracle character sets. Functions that operate
on multibyte strings take the string as a whole unit with the length of the string
calculated in bytes. Wide-character (wchar) string functions provide more flexibility in
string manipulation. They support character-based and string-based operations with
the length of the string calculated in characters.
The wide-character data type is Oracle-specific and should not be confused with the
wchar_t data type defined by the ANSI/ISO C standard. The Oracle wide-character
data type is always 4 bytes in all operating systems, whereas the size of wchar_t
depends on the implementation and the operating system. The Oracle wide-character
data type normalizes multibyte characters so that they have a fixed width for easy
processing. This guarantees no data loss for round-trip conversion between the Oracle
wide-character set and the native character set.
String manipulation can be classified into the following categories:
•

Conversion of strings between multibyte and wide character

•

Character classifications

•

Case conversion

•

Calculations of display length

•

General string manipulation, such as comparison, concatenation, and searching

Table 31-4 summarizes the OCI string manipulation functions, which are described in
this section.
Table 31-4

OCI String Manipulation Functions

Function

Purpose

OCIMultiByteInSizeToWideChar()

Convert part of a multibyte string into the
wide-character string

OCIMultiByteStrCaseConversion()

Convert a multibyte string into the specified
case and copies the result into the destination
array

OCIMultiByteStrcat()

Append a multibyte string to the destination
string

OCIMultiByteStrcmp()

Compare two multibyte strings by binary,
linguistic, or case-insensitive comparison
methods

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Table 31-4

(Cont.) OCI String Manipulation Functions

Function

Purpose

OCIMultiByteStrcpy()

Copy a multibyte string into the destination
array. It returns the number of bytes copied.

OCIMultiByteStrlen()

Return the number of bytes in a multibyte
string

OCIMultiByteStrncat()

Append, at most, n bytes from a multibyte
string to the destination string

OCIMultiByteStrncmp()

Compare two multibyte strings by binary,
linguistic, or case-insensitive comparison
methods. Each string is in the specified length

OCIMultiByteStrncpy()

Copy a specified number of bytes of a
multibyte string into the destination array

OCIMultiByteStrnDisplayLength()

Return the number of display positions
occupied by the multibyte string within the
range of n bytes

OCIMultiByteToWideChar()

Convert a NULL-terminated multibyte string
into wide-character format

"OCIWideCharInSizeToMultiByte()"

Convert part of a wide-character string to the
multibyte string

OCIWideCharMultiByteLength()

Determine the number of bytes required for a
wide character in multibyte encoding

OCIWideCharStrCaseConversion()

Convert a wide-character string into the
specified case and copies the result into the
destination array

OCIWideCharStrcat()

Append a wide-character string to the
destination string

OCIWideCharStrchr()

Search for the first occurrence of a wide
character in a string. Return a point to the
wide character if the search is successful.

OCIWideCharStrcmp()

Compare two wide-character strings by
binary, linguistic, or case-insensitive
comparison methods

OCIWideCharStrcpy()

Copy a wide-character string into a
destination array. Return the number of
characters copied.

OCIWideCharStrlen()

Return the number of characters in a widecharacter string

OCIWideCharStrncat()

Append, at most, n characters from a widecharacter string to the destination string

OCIWideCharStrncmp()

Compare two wide-character strings by
binary, linguistic, or case-insensitive methods.
Each string is a specified length.

OCIWideCharStrncpy()

Copy, at most, n characters of a widecharacter string into the destination array

OCIWideCharStrrchr()

Search for the last occurrence of a character
in a wide-character string

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Table 31-4

(Cont.) OCI String Manipulation Functions

Function

Purpose

OCIWideCharToLower()

Convert a specified wide character into the
corresponding lowercase character

OCIWideCharToMultiByte()

Convert a NULL-terminated wide-character
string into a multibyte string

OCIWideCharToUpper()

Convert a specified wide character into the
corresponding uppercase character

31.4.1 OCIMultiByteInSizeToWideChar()
Converts part of a multibyte string into the wide-character string.
Purpose
Converts part of a multibyte string into the wide-character string.
Syntax
sword OCIMultiByteInSizeToWideChar ( void
OCIWchar
size_t
const OraText
size_t
size_t

*hndl,
*dst,
dstsz,
*src,
srcsz,
*rsize );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set of the string.
dst (OUT)
Pointer to a destination buffer for wchar. It can be a NULL pointer when dstsz is zero.
dstsz (IN)
Destination buffer size in number of characters. If it is zero, then this function returns
the number of characters needed for the conversion.
src (IN)
Source string to be converted.
srcsz (IN)
Length of source string in bytes.
rsize (OUT)
Number of characters written into the destination buffer, or number of characters for
the converted string if dstsz is zero. If it is a NULL pointer, then nothing is returned.
Comments
This routine converts part of a multibyte string into the wide-character string. It
converts as many complete characters as it can until it reaches the output buffer size
limit or input buffer size limit or it reaches a NULL terminator in a source string. The
output buffer is NULL-terminated if space permits. If dstsz is zero, then this function

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returns only the number of characters not including the ending NULL terminator needed
for a converted string. If OCI_UTF16ID is specified for SQL CHAR data in the
OCIEnvNlsCreate() function, then this function produces an error.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIMultiByteToWideChar()
Converts a NULL-terminated multibyte string into wide-character format.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.2 OCIMultiByteStrCaseConversion()
Converts a multibyte string into the specified case and copies the result into the
destination array.
Purpose
Converts the multibyte string pointed to by srcstr into uppercase or lowercase as
specified by the flag and copies the result into the array pointed to by dststr.
Syntax
size_t OCIMultiByteStrCaseConversion ( void
*hndl,
OraText
*dststr,
const OraText *srcstr,
ub4
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle.
dststr (OUT)
Pointer to destination array. The result string is NULL-terminated.
srcstr (IN)
Pointer to source string.
flag (IN)
Specify the case to which to convert:
•

OCI_NLS_UPPERCASE: Convert to uppercase.

•

OCI_NLS_LOWERCASE: Convert to lowercase.

This flag can be used with OCI_NLS_LINGUISTIC to specify that the linguistic setting in the
locale is used for case conversion.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.

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Returns
The number of bytes in the result string, not including the NULL terminator.

31.4.3 OCIMultiByteStrcat()
Appends a multibyte string to the destination string.
Purpose
Appends a copy of the multibyte string pointed to by srcstr to the end of the string
pointed to by dststr.
Syntax
size_t OCIMultiByteStrcat ( void
OraText
const OraText

*hndl,
*dststr,
*srcstr );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
dststr (IN/OUT)
Pointer to the destination multibyte string for appending. The output buffer is NULLterminated.
srcstr (IN)
Pointer to the source string to append.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The number of bytes in the result string, not including the NULL terminator.
Related Topics
•

OCIMultiByteStrncat()
Appends, at most, n bytes from a multibyte string to the destination string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.4 OCIMultiByteStrcmp()
Compares two multibyte strings by binary, linguistic, or case-insensitive comparison
methods.
Purpose
Compares two multibyte strings by binary, linguistic, or case-insensitive comparison
methods.

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Syntax
int OCIMultiByteStrcmp ( void
const OraText
const OraText
int

*hndl,
*str1,
*str2,
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle.
str1 (IN)
Pointer to a NULL-terminated string.
str2 (IN)
Pointer to a NULL-terminated string.
flag (IN)
It is used to decide the comparison method. It can take one of these values:
•

OCI_NLS_BINARY: Binary comparison This is the default value.

•

OCI_NLS_LINGUISTIC: Linguistic comparison specified in the locale.

This flag can be used with OCI_NLS_CASE_INSENSITIVE for case-insensitive comparison.
For example, use OCI_NLS_LINGUISTIC|OCI_NLS_CASE_INSENSITIVE to compare strings
linguistically without regard to case.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The return values for the function are:
•

0, if str1 = str2

•

Positive, if str1 > str2

•

Negative, if str1 < str2

Related Topics
•

OCIMultiByteStrncmp()
Compares two multibyte strings by binary, linguistic, or case-insensitive
comparison methods. Each string is in the specified length.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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31.4.5 OCIMultiByteStrcpy()
Copies a multibyte string into the destination array. It returns the number of bytes
copied.
Purpose
Copies the multibyte string pointed to by srcstr into the array pointed to by dststr.
Syntax
size_t OCIMultiByteStrcpy ( void
OraText
const OraText

*hndl,
*dststr,
*srcstr );

Parameters
hndl (IN/OUT)
Pointer to the OCI environment or user session handle.
dststr (OUT)
Pointer to the destination buffer. The output buffer is NULL-terminated.
srcstr (IN)
Pointer to the source multibyte string.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The number of bytes copied, not including the NULL terminator.
Related Topics
•

OCIMultiByteStrncpy()
Copies a specified number of bytes of a multibyte string into the destination array.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.6 OCIMultiByteStrlen()
Returns the number of bytes in a multibyte string.
Purpose
Returns the number of bytes in the multibyte string pointed to by str, not including the
NULL terminator.
Syntax
size_t OCIMultiByteStrlen ( void
*hndl,
const OraText *str );

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Parameters
hndl (IN/OUT)
Pointer to the OCI environment or user session handle.
str (IN)
Pointer to the source multibyte string.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The number of bytes, not including the NULL terminator.
Related Topics
•

OCIWideCharStrlen()
Return the number of characters in a wide-character string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.7 OCIMultiByteStrncat()
Appends, at most, n bytes from a multibyte string to the destination string.
Purpose
Appends a specified number of bytes from a multibyte string to a destination string.
Syntax
size_t OCIMultiByteStrncat ( void
OraText
const OraText
size_t

*hndl,
*dststr,
*srcstr,
n );

Parameters
hndl (IN/OUT)
Pointer to OCI environment or user session handle.
dststr (IN/OUT)
Pointer to the destination multibyte string for appending.
srcstr (IN)
Pointer to the source multibyte string to append.
n (IN)
The number of bytes from srcstr to append.
Comments
This function is similar to OCIMultiByteStrcat(). At most, n bytes from srcstr are
appended to dststr. Note that the NULL terminator in srcstr stops appending, and the

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function appends as many character as possible within n bytes. The dststr parameter
is NULL-terminated. If OCI_UTF16ID is specified for SQL CHAR data in the
OCIEnvNlsCreate() function, then this function produces an error.
Returns
The number of bytes in the result string, not including the NULL terminator.
Related Topics
•

OCIMultiByteStrcat()
Appends a multibyte string to the destination string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.8 OCIMultiByteStrncmp()
Compares two multibyte strings by binary, linguistic, or case-insensitive comparison
methods. Each string is in the specified length.
Purpose
Compares two multibyte strings by binary, linguistic, or case-insensitive comparison
methods. A length is specified for each string.
Syntax
int OCIMultiByteStrncmp ( void
*hndl,
const OraText *str1,
size_t
len1,
OraText
*str2,
size_t
len2,
int
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle.
str1 (IN)
Pointer to the first string.
len1 (IN)
The length of the first string to compare.
str2 (IN)
Pointer to the second string.
len2 (IN)
The length of the second string to compare.
flag (IN)
It is used to decide the comparison method. It can take one of these values:
•

OCI_NLS_BINARY: Binary comparison. This is the default value.

•

OCI_NLS_LINGUISTIC: Linguistic comparison specified in the locale.

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This flag can be used with OCI_NLS_CASE_INSENSITIVE for case-insensitive comparison.
For example, use OCI_NLS_LINGUISTIC|OCI_NLS_CASE_INSENSITIVE to compare strings
linguistically without regard to case.
Comments
This function is similar to OCIMultiByteStrcmp(), except that, at most, len1 bytes from
str1 and len2 bytes from str2 are compared. The NULL terminator is used in the
comparison. If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate()
function, then this function produces an error.
Returns
The return values for the function are:
•

0, if str1 = str2

•

Positive, if str1 > str2

•

Negative, if str1 < str2

Related Topics
•

OCIMultiByteStrcpy()
Copies a multibyte string into the destination array. It returns the number of bytes
copied.

•

OCIMultiByteStrncpy()
Copies a specified number of bytes of a multibyte string into the destination array.

•

OCIMultiByteStrcmp()
Compares two multibyte strings by binary, linguistic, or case-insensitive
comparison methods.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.9 OCIMultiByteStrncpy()
Copies a specified number of bytes of a multibyte string into the destination array.
Purpose
Copies a multibyte string into an array.
Syntax
size_t OCIMultiByteStrncpy ( void
OraText
const OraText
size_t

*hndl,
*dststr,
*srcstr,
n );

Parameters
hndl (IN/OUT)
Pointer to OCI environment or user session handle.
dststr (IN)
Pointer to the source multibyte string.

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srcstr (OUT)
Pointer to the destination buffer.
n (IN)
The number of bytes from srcstr to copy.
Comments
This function is similar to OCIMultiByteStrcpy(). At most, n bytes are copied from the
array pointed to by srcstr to the array pointed to by dststr. Note that the NULL
terminator in srcstr stops copying, and the function copies as many characters as
possible within n bytes. The result string is NULL-terminated. If OCI_UTF16ID is specified
for SQL CHAR data in the OCIEnvNlsCreate() function, then this function produces an
error.
Returns
The number of bytes in the resulting string, not including the NULL terminator.
Related Topics
•

OCIMultiByteStrcpy()
Copies a multibyte string into the destination array. It returns the number of bytes
copied.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.10 OCIMultiByteStrnDisplayLength()
Returns the number of display positions occupied by the multibyte string within the
range of n bytes.
Purpose
Returns the number of display positions occupied by the multibyte string within the
range of n bytes.
Syntax
size_t OCIMultiByteStrnDisplayLength ( void
const OraText
size_t

*hndl,
*str1,
n );

Parameters
hndl (IN/OUT)
OCI environment or user session handle.
str1 (IN)
Pointer to a multibyte string.
n (IN)
The number of bytes to examine.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.

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Returns
The number of display positions.
Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.11 OCIMultiByteToWideChar()
Converts a NULL-terminated multibyte string into wide-character format.
Purpose
Converts an entire NULL-terminated string into the wide-character string.
Syntax
sword OCIMultiByteToWideChar ( void
OCIWchar
const OraText
size_t

*hndl,
*dst,
*src,
*rsize );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set of the string.
dst (OUT)
Destination buffer for wchar.
src (IN)
Source string to be converted.
rsize (OUT)
Number of characters converted, including NULL terminator. If it is a NULL pointer, then
nothing is returned.
Comments
The wchar output buffer is NULL-terminated. If OCI_UTF16ID is specified for SQL CHAR data
in the OCIEnvNlsCreate() function, then this function produces an error.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIWideCharToMultiByte()
Converts a NULL-terminated wide-character string into a multibyte string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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31.4.12 OCIWideCharInSizeToMultiByte()
Converts part of a wide-character string to the multibyte string.
Purpose
Converts part of a wide-character string to multibyte format.
Syntax
sword OCIWideCharInSizeToMultiByte ( void
OraText
size_t
const OCIWchar
size_t
size_t

*hndl,
*dst,
dstsz,
*src,
srcsz,
*rsize );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set of string.
dst (OUT)
Destination buffer for multibyte. It can be a NULL pointer if dstsz is zero.
dstsz (IN)
Destination buffer size in bytes. If it is zero, then the function returns the size in bytes
need for converted string.
src (IN)
Source wchar string to be converted.
srcsz (IN)
Length of source string in characters.
rsize (OUT)
Number of bytes written into destination buffer, or number of bytes needed to store
the converted string if dstsz is zero. If it is a NULL pointer, then nothing is returned.
Comments
Converts part of a wide-character string into the multibyte format. It converts as many
complete characters as it can until it reaches the output buffer size or the input buffer
size or until it reaches a NULL terminator in the source string. The output buffer is NULLterminated if space permits. If dstsz is zero, then the function returns the size in bytes,
not including the NULL terminator needed to store the converted string. If OCI_UTF16ID is
specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this function
produces an error.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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31.4.13 OCIWideCharMultiByteLength()
Determines the number of bytes required for a wide character in multibyte encoding.
Purpose
Determines the number of bytes required for a wide character in multibyte encoding.
Syntax
size_t OCIWideCharMultiByteLength ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar character.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in function, then this function produces an
error.
Returns
The number of bytes required for the wide character.
Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.14 OCIWideCharStrCaseConversion()
Converts a wide-character string into the specified case and copies the result into the
destination array.
Purpose
Converts a wide-character string into a specified case and copies the result into the
destination array.
Syntax
size_t OCIWideCharStrCaseConversion ( void
OraText
const OraText
ub4

*hndl,
*dststr,
*srcstr,
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle.

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dststr (OUT)
Pointer to destination array. The result string is NULL-terminated.
srcstr (IN)
Pointer to source string.
flag (IN)
Specify the case to which to convert:
•

OCI_NLS_UPPERCASE: Convert to uppercase.

•

OCI_NLS_LOWERCASE: Convert to lowercase.

This flag can be used with OCI_NLS_LINGUISTIC to specify that the linguistic setting in the
locale is used for case conversion.
Comments
Converts the wide-character string pointed to by srcstr into uppercase or lowercase
as specified by the flag and copies the result into the array pointed to by dststr. If
OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The number of bytes in the result string, not including the NULL terminator.
Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.15 OCIWideCharStrcat()
Appends a wide-character string to the destination string.
Purpose
Appends the wide-character string pointed to by wsrcstr to the wide-character string
pointed to by wdststr.
Syntax
size_t OCIWideCharStrcat ( void
OCIWchar
const OCIWchar

*hndl,
*wdststr,
*wsrcstr );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wdststr (IN/OUT)
Pointer to the destination wchar string. The output buffer is NULL-terminated.
wsrcstr (IN)
Pointer to the source wide-character string to append.

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Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The number of characters in the result string, not including the NULL terminator.
Related Topics
•

OCIWideCharStrncat()
Appends, at most, n characters from a wide-character string to the destination
string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.16 OCIWideCharStrchr()
Searches for the first occurrence of a wide character in a string. Returns a point to the
wide character if the search is successful.
Purpose
Searches for the first occurrence of a specified character in a wide-character string.
Syntax
OCIWchar *OCIWideCharStrchr ( void
const OCIWchar
OCIWchar

*hndl,
*wstr,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wstr (IN)
Pointer to the wchar string to search.
wc (IN)
The wchar to search for.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
A wchar pointer if successful; otherwise, a NULL pointer.
Related Topics
•

OCIWideCharStrrchr()
Searches for the last occurrence of a character in a wide-character string.

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•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.17 OCIWideCharStrcmp()
Compares two wide-character strings by binary, linguistic, or case-insensitive
comparison methods.
Purpose
Compares two wide-character strings by binary (based on wchar encoding value),
linguistic, or case-insensitive comparison methods.
Syntax
int OCIWideCharStrcmp ( void
const OCIWchar
const OCIWchar
int

*hndl,
*wstr1,
*wstr2,
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wstr1 (IN)
Pointer to a NULL-terminated wchar string.
wstr2 (IN)
Pointer to a NULL-terminated wchar string.
flag (IN)
Used to decide the comparison method. It can take one of these values:
•

OCI_NLS_BINARY: Binary comparison. This is the default value.

•

OCI_NLS_LINGUISTIC: Linguistic comparison specified in the locale definition.

This flag can be used with OCI_NLS_CASE_INSENSITIVE for case-insensitive comparison.
For example, use OCI_NLS_LINGUISTIC|OCI_NLS_CASE_INSENSITIVE to compare strings
linguistically without regard to case.
The UNICODE_BINARY sort method cannot be used with OCIWideCharStrcmp() to
perform a linguistic comparison of supplied wide-character arguments.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The return values for the function are:
•

0, if wstr1 = wstr2

•

Positive, if wstr1 > wstr2

•

Negative, if wstr1 < wstr2

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Related Topics
•

OCIWideCharStrncmp()
Compares two wide-character strings by binary, linguistic, or case-insensitive
methods. Each string is a specified length.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.18 OCIWideCharStrcpy()
Copies a wide-character string into a destination array. Returns the number of
characters copied.
Purpose
Copies a wide-character string into an array.
Syntax
size_t OCIWideCharStrcpy ( void
OCIWchar
const OCIWchar

*hndl,
*wdststr,
*wsrcstr );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wdststr (OUT)
Pointer to the destination wchar buffer. The result string is NULL-terminated.
wsrcstr (IN)
Pointer to the source wchar string.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
The number of characters copied, not including the NULL terminator.
Related Topics
•

OCIWideCharStrncpy()
Copies, at most, n characters of a wide-character string into the destination array.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.19 OCIWideCharStrlen()
Return the number of characters in a wide-character string.
Purpose
Returns the number of characters in a wide-character string.

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Syntax
size_t OCIWideCharStrlen ( void
const OCIWchar

*hndl,
*wstr );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wstr (IN)
Pointer to the source wchar string.
Comments
Returns the number of characters in the wchar string pointed to by wstr, not including
the NULL terminator. If OCI_UTF16ID is specified for SQL CHAR data in the
OCIEnvNlsCreate() function, then this function produces an error.
Returns
The number of characters, not including the NULL terminator.
Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.20 OCIWideCharStrncat()
Appends, at most, n characters from a wide-character string to the destination string.
Purpose
Appends, at most, n characters from a wide-character string to the destination.
Syntax
size_t OCIWideCharStrncat ( void
OCIWchar
const OCIWchar
size_t

*hndl,
*wdststr,
*wsrcstr,
n );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wdststr (IN/OUT)
Pointer to the destination wchar string.
wsrcstr (IN)
Pointer to the source wchar string.
n (IN)
Number of characters from wsrcstr to append.

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Comments
This function is similar to OCIWideCharStrcat(). At most, n characters from wsrcstr are
appended to wdststr. Note that the NULL terminator in wsrcstr stops appending. The
wdststr parameter is NULL-terminated. If OCI_UTF16ID is specified for SQL CHAR data in
the OCIEnvNlsCreate() function, then this function produces an error.
Returns
The number of characters in the result string, not including the NULL terminator.
Related Topics
•

OCIWideCharStrcat()
Appends a wide-character string to the destination string.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.21 OCIWideCharStrncmp()
Compares two wide-character strings by binary, linguistic, or case-insensitive
methods. Each string is a specified length.
Purpose
Compares two wide-character strings by binary, linguistic, or case-sensitive methods.
Each string has a specified length.
Syntax
int OCIWideCharStrncmp ( void
const OCIWchar
size_t
const OCIWchar
size_t
int

*hndl,
*wstr1,
len1,
*wstr2,
len2,
flag );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wstr1 (IN)
Pointer to the first wchar string.
len1 (IN)
The length from the first string for comparison.
wstr2 (IN)
Pointer to the second wchar string.
len2 (IN)
The length from the second string for comparison.
flag (IN)
It is used to decide the comparison method. It can take one of these values:

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•

OCI_NLS_BINARY: For the binary comparison, this is default value.

•

OCI_NLS_LINGUISTIC: For the linguistic comparison specified in the locale.

This flag can be used with OCI_NLS_CASE_INSENSITIVE for case-insensitive comparison.
For example, use OCI_NLS_LINGUISTIC|OCI_NLS_CASE_INSENSITIVE to compare strings
linguistically without regard to case.
Comments
This function is similar to OCIWideCharStrcmp(). It compares two wide-character strings
by binary, linguistic, or case-insensitive comparison methods. At most, len1 bytes from
wstr1 and len2 bytes from wstr2 are compared. The NULL terminator is used in the
comparison. If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate()
function, then this function produces an error.
The UNICODE_BINARY sort method cannot be used with OCIWideCharStrncmp() to
perform a linguistic comparison of supplied wide-character arguments.
Returns
The return values for the function are:
•

0, if wstr1 = wstr2

•

Positive, if wstr1 > wstr2

•

Negative, if wstr1 < wstr2

Related Topics
•

OCIWideCharStrcmp()
Compares two wide-character strings by binary, linguistic, or case-insensitive
comparison methods.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.22 OCIWideCharStrncpy()
Copies, at most, n characters of a wide-character string into the destination array.
Purpose
Copies, at most, n characters from a wide-character string into a destination.
Syntax
size_t OCIWideCharStrncpy ( void
OCIWchar
const OCIWchar
size_t

*hndl,
*wdststr,
*wsrcstr,
n );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wdststr (OUT)
Pointer to the destination wchar buffer.

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wsrcstr (IN)
Pointer to the source wchar string.
n (IN)
Number of characters from wsrcstr to copy.
Comments
This function is similar to OCIWideCharStrcpy(), except that, at most, n characters are
copied from the array pointed to by wsrcstr to the array pointed to by wdststr. Note
that the NULL terminator in wdststr stops copying, and the result string is NULLterminated. If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate()
function, then this function produces an error.
Returns
The number of characters copied, not including the NULL terminator.
Related Topics
•

OCIWideCharStrcpy()
Copies a wide-character string into a destination array. Returns the number of
characters copied.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.23 OCIWideCharStrrchr()
Searches for the last occurrence of a character in a wide-character string.
Purpose
Searches for the last occurrence of a character in a wide-character string.
Syntax
OCIWchar *OCIWideCharStrrchr ( void
const OCIWchar
OCIWchar

*hndl,
*wstr,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wstr (IN)
Pointer to the wchar string to search in.
wc (IN)
The wchar to search for.
Comments
Searches for the last occurrence of wc in the wchar string pointed to by wstr. If
OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.

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Returns
The wchar pointer if successful; otherwise, a NULL pointer.
Related Topics
•

OCIWideCharStrchr()
Searches for the first occurrence of a wide character in a string. Returns a point to
the wide character if the search is successful.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.24 OCIWideCharToLower()
Converts a specified wide character into the corresponding lowercase character.
Purpose
Converts the wide-character string specified by wc into the corresponding lowercase
character, if it exists, in the specified locale. If no corresponding lowercase character
exists, then it returns wc itself.
Syntax
OCIWchar OCIWideCharToLower ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for lowercase conversion.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
A wchar.
Related Topics
•

OCIWideCharToUpper()
Converts a specified wide character into the corresponding uppercase character.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

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31.4.25 OCIWideCharToMultiByte()
Converts a NULL-terminated wide-character string into a multibyte string.
Purpose
Converts an entire NULL-terminated wide-character string into a multibyte string.
Syntax
sword OCIWideCharToMultiByte ( void
OraText
const OCIWchar
size_t

*hndl,
*dst,
*src,
*rsize );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set of the string.
dst (OUT)
Destination buffer for a multibyte string. The output buffer is NULL-terminated.
src (IN)
Source wchar string to be converted.
rsize (OUT)
Number of bytes written into destination buffer. If it is a NULL pointer, then nothing is
returned.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIMultiByteToWideChar()
Converts a NULL-terminated multibyte string into wide-character format.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.4.26 OCIWideCharToUpper()
Converts a specified wide character into the corresponding uppercase character.
Purpose
Converts the wide-character string specified by wc into the corresponding uppercase
character, if it exists, in the specified locale. If no corresponding uppercase character
exists, then it returns wc itself.

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Syntax
OCIWchar OCIWideCharToUpper ( void
*hndl,
OCIWchar wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for uppercase conversion.
Comments
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
A wchar.
Related Topics
•

OCIWideCharToLower()
Converts a specified wide character into the corresponding lowercase character.

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.5 OCI Character Classification Functions
Lists and describes OCI character classification functions.
Table 31-5 lists the OCI character classification functions that are described in this
section.
Table 31-5

OCI Character Classification Functions

Function

Purpose

OCIWideCharIsAlnum()

Test whether the wide character is a letter or a
decimal digit

OCIWideCharIsAlpha()

Test whether the wide character is a letter

OCIWideCharIsCntrl()

Test whether the wide character is a control
character

OCIWideCharIsDigit()

Test whether the wide character is a decimal digital
character

OCIWideCharIsGraph()

Test whether the wide character is a graph
character

OCIWideCharIsLower()

Test whether the wide character is a lowercase
character

OCIWideCharIsPrint()

Test whether the wide character is a printable
character

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Table 31-5

(Cont.) OCI Character Classification Functions

Function

Purpose

OCIWideCharIsPunct()

Test whether the wide character is a punctuation
character

OCIWideCharIsSingleByte()

Test whether the wide character is a single-byte
character when converted to multibyte

OCIWideCharIsSpace()

Test whether the wide character is a space
character

OCIWideCharIsUpper()

Test whether the wide character is an uppercase
character

OCIWideCharIsXdigit()

Test whether the wide character is a hexadecimal
digit

31.5.1 OCIWideCharIsAlnum()
Tests whether the wide character is a letter or a decimal digit.
Purpose
Tests whether a wide character is a letter or a decimal digit.
Syntax
boolean OCIWideCharIsAlnum ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.2 OCIWideCharIsAlpha()
Tests whether the wide character is a letter.
Purpose
Tests whether a wide character is a letter.
Syntax
boolean OCIWideCharIsAlpha ( void
*hndl,
OCIWchar wc );

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Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.3 OCIWideCharIsCntrl()
Tests whether the wide character is a control character.
Purpose
Tests whether a wide character is a control character.
Syntax
boolean OCIWideCharIsCntrl ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.4 OCIWideCharIsDigit()
Test whether the wide character is a decimal digital character.
Purpose
Tests whether a wide character is a decimal digit character.
Syntax
boolean OCIWideCharIsDigit ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.

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wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.5 OCIWideCharIsGraph()
Tests whether a wide character is a graph character.
Purpose
A graph character is a character with a visible representation and normally includes
alphabetic letters, decimal digits, and punctuation.
Syntax
boolean OCIWideCharIsGraph ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.6 OCIWideCharIsLower()
Tests whether a wide character is a lowercase letter.
Purpose
Tests whether a wide character is a lowercase letter.
Syntax
boolean OCIWideCharIsLower ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

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31.5.7 OCIWideCharIsPrint()
Tests whether a wide character is a printable character.
Purpose
Tests whether a wide character is a printable character.
Syntax
boolean OCIWideCharIsPrint ( void
*hndl,
OCIWchar wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.8 OCIWideCharIsPunct()
Tests whether a wide character is a punctuation character.
Purpose
Tests whether a wide character is a punctuation character.
Syntax
boolean OCIWideCharIsPunct ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

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31.5.9 OCIWideCharIsSingleByte()
Tests whether a wide character is a single-byte character when converted to multibyte.
Purpose
Tests whether a wide character is a single-byte character when converted to multibyte.
Syntax
boolean OCIWideCharIsSingleByte ( void
*hndl,
OCIWchar wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.10 OCIWideCharIsSpace()
Tests whether a wide character is a space character.
Purpose
A space character causes white space only in displayed text (for example, space, tab,
carriage return, new line, vertical tab, or form feed).
Syntax
boolean OCIWideCharIsSpace ( void
*hndl,
OCIWchar wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

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31.5.11 OCIWideCharIsUpper()
Tests whether a wide character is an uppercase letter.
Purpose
Tests whether a wide character is an uppercase letter.
Syntax
boolean OCIWideCharIsUpper ( void
OCIWchar

*hndl,
wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

31.5.12 OCIWideCharIsXdigit()
Tests whether the wide character is a hexadecimal digit.
Purpose
Tests whether a wide character is a hexadecimal digit (0 through 9, A through F, a
through f).
Syntax
boolean OCIWideCharIsXdigit ( void
*hndl,
OCIWchar wc );

Parameters
hndl (IN/OUT)
OCI environment or user session handle to determine the character set.
wc (IN)
The wchar for testing.
Returns
TRUE or FALSE.

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31.6 OCI Character Set Conversion Functions
Lists and describes OCI character set conversion functions.
Conversion between Oracle Database character sets and Unicode (16-bit, fixed-width
Unicode encoding) is supported. Replacement characters are used if a character has
no mapping from Unicode to the Oracle Database character set. Therefore, conversion
back to the original character set is not always possible without data loss.
Table 31-6 lists the OCI character set conversion functions.
Table 31-6

OCI Character Set Conversion Functions

Function

Purpose

OCICharSetConversionIsReplacementUsed()

Indicate whether replacement
characters were used for
characters that could not be
converted in the last invocation
of OCINlsCharSetConvert() or
OCICharSetToUnicode()

OCICharSetToUnicode()

Convert a multibyte string to
Unicode

OCINlsCharSetConvert()

Convert a string from one
character set to another

OCIUnicodeToCharSet()

Convert a Unicode string into
multibyte

31.6.1 OCICharSetConversionIsReplacementUsed()
Indicates whether replacement characters were used for characters that could not be
converted in the last invocation of OCINlsCharSetConvert() or OCICharSetToUnicode().
Purpose
Indicates whether the replacement character was used for characters that could not be
converted during the last invocation of OCICharSetToUnicode() or
OCINlsCharSetConvert().
Syntax
boolean OCICharSetConversionIsReplacementUsed ( void *hndl );

Parameters
hndl (IN/OUT)
Pointer to an OCI environment or user session handle.
Comments
Conversion between the Oracle Database character set and Unicode (16-bit, fixedwidth Unicode encoding) is supported. Replacement characters are used if there is no
mapping for a character from Unicode to the Oracle Database character set. Thus, not

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every character can make a round-trip conversion to the original character. Data loss
occurs with certain characters.
Returns
The function returns TRUE if the replacement character was used when
OCINlsCharSetConvert() or OCICharSetToUnicode() was last invoked. Otherwise the
function returns FALSE.
Related Topics
•

OCINlsCharSetConvert()
Converts a string from one character set to another.

•

OCICharSetToUnicode()
Converts a multibyte string to Unicode.

31.6.2 OCICharSetToUnicode()
Converts a multibyte string to Unicode.
Purpose
Converts a multibyte string pointed to by src to Unicode out to the array pointed to by
dst.
Syntax
sword OCICharSetToUnicode ( void
ub2
size_t
const OraText
size_t
size_t

*hndl,
*dst,
dstlen,
*src,
srclen,
*rsize );

Parameters
hndl (IN/OUT)
Pointer to an OCI environment or user session handle.
dst (OUT)
Pointer to a destination buffer.
dstlen (IN)
The size of the destination buffer in characters.
src (IN)
Pointer to a multibyte source string.
srclen (IN)
The size of the source string in bytes.
rsize (OUT)
The number of characters converted. If it is a NULL pointer, then nothing is returned.
Comments
The conversion stops when it reaches the source limitation or destination limitation.
The function returns the number of characters converted into a Unicode string. If

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dstlen is 0, then the function scans the string, counts the number of characters, and
returns the number of characters out to rsize, but does not convert the string.

If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
OCI_SUCCESS, OCI_INVALID_HANDLE, or OCI_ERROR.

Related Topics
•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.6.3 OCINlsCharSetConvert()
Converts a string from one character set to another.
Purpose
Converts a string pointed to by src in the character set specified by srcid to the array
pointed to by dst in the character set specified by dstid. The conversion stops when it
reaches the data size limitation of either the source or the destination. The function
returns the number of bytes converted into the destination buffer.
Syntax
sword OCINlsCharSetConvert ( void
OCIError
ub2
void
size_t
ub2
const void
size_t
size_t

*hndl,
*errhp,
dstid,
*dstp,
dstlen,
srcid,
*srcp,
srclen,
*rsize );

Parameters
hndl (IN/OUT)
Pointer to an OCI environment or user session handle.
errhp (IN/OUT)
OCI error handle. If there is an error, then it is recorded in errhp and the function
returns a NULL pointer. Diagnostic information can be obtained by calling
OCIErrorGet().
dstid (IN)
Character set ID for the destination buffer.
dstp (OUT)
Pointer to the destination buffer.
dstlen (IN)
The maximum size in bytes of the destination buffer.

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srcid (IN)
Character set ID for the source buffer.
srcp (IN)
Pointer to the source buffer.
srclen (IN)
The length in bytes of the source buffer.
rsize (OUT)
The number of characters converted. If the pointer is NULL, then nothing is returned.
Comments
Although either the source or the destination character set ID can be specified as
OCI_UTF16ID, the length of the original and the converted data is represented in bytes,
rather than number of characters. Note that the conversion does not stop when it
encounters null data. To get the character set ID from the character set name, use
OCINlsCharSetNameToId(). To check if derived data in the destination buffer contains
replacement characters, use OCICharSetConversionIsReplacementUsed(). The buffers
should be aligned with the byte boundaries appropriate for the character sets. For
example, the ub2 data type is necessary to hold strings in UTF-16.
Returns
OCI_SUCCESS or OCI_ERROR; number of bytes converted.

Related Topics
•

OCINlsCharSetNameToId()
Returns the Oracle Database character set ID for the specified Oracle Database
character set name.

•

OCICharSetConversionIsReplacementUsed()
Indicates whether replacement characters were used for characters that could not
be converted in the last invocation of OCINlsCharSetConvert() or
OCICharSetToUnicode().

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

31.6.4 OCIUnicodeToCharSet()
Converts a Unicode string into multibyte string out to an array.
Purpose
Converts a Unicode string to a multibyte string out to an array.
Syntax
sword OCIUnicodeToCharSet ( void
OraText
size_t
const ub2
size_t
size_t

*hndl,
*dst,
dstlen,
*src,
srclen,
*rsize );

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Parameters
hndl (IN/OUT)
Pointer to an OCI environment or user session handle.
dst (OUT)
Pointer to a destination buffer.
dstlen (IN)
The size of the destination buffer in bytes.
src (IN)
Pointer to a Unicode string.
srclen (IN)
The size of the source string in characters.
rsize (OUT)
The number of bytes converted. If it is a NULL pointer, then nothing is returned.
Comments
The conversion stops when it reaches the source limitation or destination limitation.
The function returns the number of bytes converted into a multibyte string. If dstlen is
zero, then the function returns the number of bytes out to rsize without conversion.
If a Unicode character is not convertible for the character set specified in OCI
environment or user session handle, then a replacement character is used. In this
case, OCICharSetConversionIsReplacementUsed() returns TRUE.
If OCI_UTF16ID is specified for SQL CHAR data in the OCIEnvNlsCreate() function, then this
function produces an error.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCICharSetConversionIsReplacementUsed()
Indicates whether replacement characters were used for characters that could not
be converted in the last invocation of OCINlsCharSetConvert() or
OCICharSetToUnicode().

•

OCIEnvNlsCreate()
Creates and initializes an environment handle for OCI functions to work under.

31.7 OCI Messaging Functions
Lists and describes OCI messaging functions.
The user message API provides a simple interface for cartridge developers to retrieve
their own messages and Oracle Database messages.

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See Also:
Oracle Database Data Cartridge Developer's Guide

Table 31-7 lists the OCI messaging functions that are described in this section.
Table 31-7

OCI Messaging Functions

Function

Purpose

OCIMessageClose()

Close a message handle and free any
memory associated with the handle

OCIMessageGet()

Retrieve a message. If the buffer is not zero,
then the function copies the message into the
buffer

OCIMessageOpen()

Open a message handle in a specified
language

31.7.1 OCIMessageClose()
Closes a message handle and frees any memory associated with this handle.
Purpose
Closes a message handle and frees any memory associated with this handle.
Syntax
sword OCIMessageClose ( void
*hndl,
OCIError *errhp,
OCIMsg
*msgh );

Parameters
hndl (IN/OUT)
Pointer to an OCI environment or user session handle for the message language.
errhp (IN/OUT)
The OCI error handle. If there is an error, then it is recorded in errhp, and the function
returns a NULL pointer. Diagnostic information can be obtained by calling
OCIErrorGet().
msgh (IN/OUT)
A pointer to a message handle that was previously opened by OCIMessageOpen().
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

Related Topics
•

OCIMessageOpen()
Opens a message-handling facility in a specified language.

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•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

31.7.2 OCIMessageGet()
Gets a message with the given message number.
Purpose
Gets a message with the given message number.
Syntax
OraText *OCIMessageGet ( OCIMsg
ub4
OraText
size_t

*msgh,
msgno,
*msgbuf,
buflen );

Parameters
msgh (IN/OUT)
Pointer to a message handle that was previously opened by OCIMessageOpen().
msgno (IN)
The message number.
msgbuf (OUT)
Pointer to a destination buffer for the retrieved message. If buflen is zero, then it can
be a NULL pointer.
buflen (IN)
The size of the destination buffer.
Comments
If buflen is not zero, then the function copies the message into the buffer pointed to by
msgbuf. If buflen is zero, then the message is copied into a message buffer inside the
message handle pointed to by msgh.
Returns
It returns the pointer to the NULL-terminated message string. If the translated message
cannot be found, then it tries to return the equivalent English message. If the
equivalent English message cannot be found, then it returns a NULL pointer.
Related Topics
•

OCIMessageOpen()
Opens a message-handling facility in a specified language.

31.7.3 OCIMessageOpen()
Opens a message-handling facility in a specified language.
Purpose
Opens a message-handling facility in a specified language.

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Syntax
sword OCIMessageOpen ( void
OCIError
OCIMsg
const OraText
const OraText
OCIDuration

*hndl,
*errhp,
*msghp,
*product,
*facility,
dur );

Parameters
hndl (IN/OUT)
Pointer to an OCI environment or user session handle for the message language.
errhp (IN/OUT)
The OCI error handle. If there is an error, then it is recorded in errhp, and the function
returns a NULL pointer. Diagnostic information can be obtained by calling
OCIErrorGet().
msghp (OUT)
A message handle for return.
product (IN)
A pointer to a product name. The product name is used to locate the directory for
messages. Its location depends on the operating system. For example, in Solaris, the
directory of message files for the rdbms product is $ORACLE_HOME/rdbms.
facility (IN)
A pointer to a facility name in the product. It is used to construct a message file name.
A message file name follows the conversion with facility as prefix. For example, the
message file name for the img facility in the American language is imgus.msb, where us
is the abbreviation for the American language and msb is the message binary file
extension.
dur (IN)
The duration for memory allocation for the return message handle. It can have the
following values:
•

OCI_DURATION_PROCESS

•

OCI_DURATION_SESSION

•

OCI_DURATION_STATEMENT

Comments
OCIMessageOpen() first tries to open the message file corresponding to hndl. If it

succeeds, then it uses that file to initialize a message handle. If it cannot find the
message file that corresponds to the language, then it looks for a primary language file
as a fallback. For example, if the Latin American Spanish file is not found, then it tries
to open the Spanish file. If the fallback fails, then it uses the default message file,
whose language is AMERICAN. The function returns a pointer to a message handle into
the msghp parameter.
Returns
OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

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Related Topics
•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

31-49

32
OCI XML DB Functions
This chapter describes the OCI XML DB functions.
This chapter contains these topics:
•

Introduction to XML DB Support in OCI

•

OCI XML DB Functions

32.1 Introduction to XML DB Support in OCI
This chapter describes the XML DB functions in detail.

See Also:
OCI Support for XML

32.1.1 Conventions for OCI Functions
Describes conventions used in describing each function.
See the Conventions for OCI Functions for the conventions used in describing each
function. The entries for each function may also contain the following information:

32.1.2 Returns
Describes the function return values.
Unless otherwise stated, the function returns the values described in Table 32-1.
Table 32-1

Function Return Values

Return Value

Meaning

OCI_SUCCESS

The operation succeeded.

OCI_ERROR

The operation failed. The specific error can be
retrieved by calling OCIErrorGet() on the error handle
passed to the function.

OCI_INVALID_HANDLE

The OCI handle passed to the function is invalid.

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See Also:
Error Handling in OCI for more information about return codes and error
handling

32.2 OCI XML DB Functions
Lists and describes OCI XML DB Functions.
Table 32-2 lists the OCI XML DB functions that are described in this chapter.
Table 32-2

OCI XML DB Functions

Function

Purpose

OCIBinXmlCreateReposCtxFromConn()

Create metadata connection context

OCIBinXmlCreateReposCtxFromCPool()

Create metadata connection context
connection pool

OCIBinXmlSetFormatPref()

Specify that images transferred are in
binary XML format

OCIBinXmlSetReposCtxForConn()

Associate data connection with the
metadata connection

OCIXmlDbFreeXmlCtx()

Free an XML context

OCIXmlDbInitXmlCtx()

Initialize an XML context for XML data
from the database

32.2.1 OCIBinXmlCreateReposCtxFromConn()
Creates a metadata connection context.
Purpose
Creates a metadata connection context (OCIBinXmlReposCtx) from the specified OCIEnv/
OCISvcCtx dedicated OCI connection. Note that this connection is dedicated to
metadata use.
Syntax
sword OCIBinXmlCreateReposCtxFromConn (

OCIEnv
*env,
OCISvcCtx
*svcctx,
OCIError
*err,
OCIBinXmlReposCtx **ctx);

Parameters
env (IN)
The environment handle.
svcctx (IN)
The handle to the connection to be used to access the metadata.

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err (IN)
The error handle.
ctx (OUT)
The metadata context that is created and returned.
Returns
Returns -1 for error, 0 for success. The err parameter contains more information about
the error.
Related Topics
•

OCIBinXmlCreateReposCtxFromCPool()
Creates a metadata connection context from the specified connection pool.

32.2.2 OCIBinXmlCreateReposCtxFromCPool()
Creates a metadata connection context from the specified connection pool.
Purpose
Creates a metadata connection context (OCIBinXmlReposCtx) from the specified
connection pool. A connection from the connection pool is used whenever any
information from the token repository is needed.
Syntax
sword OCIBinXmlCreateReposCtxFromCPool (

OCIEnv
*env,
OCICPool
*cpool,
OCIError
*err,
OCIBinXmlReposCtx **ctx);

Parameters
env (IN)
The environment handle.
cpool (IN)
The handle to the connection to be used to access the metadata.
err (IN)
The error handle.
ctx (OUT)
The metadata context that is created and returned.
Returns
Returns -1 for error, 0 for success. The err parameter contains more information about
the error.
Related Topics
•

OCIBinXmlCreateReposCtxFromConn()
Creates a metadata connection context.

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32.2.3 OCIBinXmlSetFormatPref()
Specifies that the images being transferred between client and server for the XML
document be in binary XML format.
Purpose
In the future, all communication will be in the binary XML format. Binary XML-aware
applications can set this.
Syntax
sword OCIBinXmlSetFormatPref (

xmldomdoc
ub4

*doc,
formattype);

Parameters
doc (IN)
The pointer to the domdoc to which the preference is to be applied.
formattype (IN)
The type of format to be used for pickling. Currently the only values allowed are
OCIXML_FORMATTYPE_TEXT and OCIXML_FORMATTYPE_BINXML.
Returns
Returns -1 for error, 0 for success.
Related Topics
•

OCIBinXmlSetReposCtxForConn()
Associates the data connection with the metadata connection.

32.2.4 OCIBinXmlSetReposCtxForConn()
Associates the data connection with the metadata connection.
Purpose
Note that with a dedicated connection, the environment handle must be the same for
the data connection and for the metadata connection.
Syntax
sword OCIBinXmlSetReposCtxForConn (

OCISvcCtx
*dataconn,
OCIBinXmlReposCtx *reposctx);

Parameters
dataconn (IN)
The data connection handle.
reposctx (IN)
The pointer to the metadata connection.

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Returns
Returns -1 for error, 0 for success. The err parameter contains more information about
the error.
Related Topics
•

OCIBinXmlSetFormatPref()
Specifies that the images being transferred between client and server for the XML
document be in binary XML format.

32.2.5 OCIXmlDbFreeXmlCtx()
Frees an XML context.
Purpose
Frees any allocations made by the call to OCIXmlDbInitXmlCtx().
Syntax
void OCIXmlDbFreeXmlCtx ( xmlct

*xctx );

Parameters
xctx (IN)
The XML context to terminate.
Comments

See Also:
Using OCI XML DB Functions for a usage example

Returns
Returns -1 for error, 0 for success.
Related Topics
•

OCIXmlDbInitXmlCtx()
Initializes an XML context.

32.2.6 OCIXmlDbInitXmlCtx()
Initializes an XML context.
Purpose
Initializes an XML context for XML data from the database.
Syntax
xmlctx *OCIXmlDbInitXmlCtx (

OCIEnv
OCISvcCtx

*envhp,
*svchp,

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OCIError
ocixmldbparam
ub4

*errhp,
*params,
num_params );

Parameters
envhp (IN)
The OCI environment handle.
svchp (IN)
The OCI service handle.
errhp (IN)
The OCI error handle.
params (IN)
The optional possible values in this array are pointers to either the OCI duration, in
which the default value is OCI_DURATION_SESSION, or to an error handler that is a userregistered callback of prototype:
void (*err_handler) (sword errcode, (const OraText *) errmsg);

The two parameters of err_handler are:
errcode (OUT)
A numeric error value.
errmsg (OUT)
The error message text.
num_params (IN)
Number of parameters to be read from params. If the value of num_params exceeds the
size of array params, unexpected behavior results.
Comments

See Also:
Using OCI XML DB Functions for a usage example

Returns
Returns either:
•

A pointer to structure xmlctx, with error handler and callbacks populated with
appropriate values. This is later used for all OCI calls.

•

NULL, if no database connection is available.

Related Topics
•

OCIXmlDbFreeXmlCtx()
Frees an XML context.

32-6

33
Oracle ODBC Driver
The Oracle ODBC Driver enables ODBC applications on Microsoft Windows, as well
as UNIX platforms like Linux, Solaris, IBM Advanced Interactive eXecutive (AIX), HPUX Itaniutm, and IBM Linux on Platform z read and write access to Oracle® databases
through the ODBC interface using Oracle Net Services software.
This chapter is a placeholder to indicate that information about using the Oracle ODBC
Driver can be found in Oracle Database Development Guide and in the Oracle ODBC
Help set.

33-1

34
Introduction to the OCI Interface for
XStream
This chapter provides an overview of the OCI interface for XStream.
The Oracle Call Interface (OCI) includes an interface for XStream. This chapter
provides an introduction to the OCI interface for XStream.
This chapter contains these topics:
•

About the XStream Interface

•

Handler and Descriptor Attributes

See Also:
•

Oracle Database XStream Guide for detailed information about XStream
Out concepts

•

Oracle Database XStream Guide for information about configuring
XStream Out

•

OCI XStream Functions for information about OCI XStream functions

34.1 About the XStream Interface
Since Oracle Database 11g Release 2, APIs, known as XStream Out and XStream In,
are available.
This technology enables high performance, near real-time information-sharing
infrastructure between Oracle databases and non-Oracle databases, non-RDBMS
Oracle products, file systems, third party software applications, and so on. XStream is
built on the infrastructure used by Oracle Streams.

See Also:
OCI XStream functions in OCI XStream Functions

34.1.1 XStream Out
XStream Out allows a remote client to attach to an outbound server and extract row
changes in the form of logical change records (LCRs).
To use XStream Out, a capture process and an outbound server must be created. All
data types supported by Oracle Streams, including LOB, LONG, and XMLType, are

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About the XStream Interface

supported by XStream. The capture process and the outbound server need not be on
the same database instance. After the capture process and the outbound server have
started, row changes are captured and sent to the outbound server. An external client
application can connect to this outbound server using OCI. After the connection is
established, the client application can loop while waiting for LCRs from the outbound
server. The client application can register a client-side callback to be invoked each
time an LCR is received. At any time, the client application can detach from the
outbound server as needed. Upon restart, the outbound server knows where in the
redo stream to start streaming LCRs to the client application.

See Also:
•

Oracle Database XStream Guide for an introduction to XStream Out

•

Oracle Streams Concepts and Administration for the basics of LCRs

34.1.2 XStream In
To replicate non-Oracle data into Oracle databases, use XStream In.
This technology allows a remote client application to attach to an inbound server and
send row and DDL changes in the form of LCRs.
An external client application connects to the inbound server using OCI. After the
connection is established, the client application acts as the capture agent for the
inbound server by streaming LCRs to it. A client application can attach to only one
inbound server for each database connection, and each inbound server only allows
one client application to attach to it.

See Also:
XStream In concepts in Oracle Database XStream Guide

34.1.3 Position Order and LCR Streams
Each LCR has a position attribute.
The position of an LCR identifies its placement in the stream of LCRs in a transaction.

See Also:
Position order in an LCR in Oracle Database XStream Guide

34.1.4 XStream and Character Sets
For XStream Out, in general, setting the client application character set to the
outbound server database character set is the best practice.

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XStream Out implicitly converts character data in LCRs from the outbound server
database character set to the client application character set. XStream In implicitly
converts character data in LCRs from the client application character set to the
inbound server database character set.
To improve performance, complete the following tasks:
•

Analyze the LCR data flow from the source to the destination.

•

Set the client character set of the OCI client application to the one that minimizes
character conversion, incurs no data loss, and takes advantage of the implicit
conversion done by XStream or the destination.

34.2 Handler and Descriptor Attributes
Describes the attributes for OCI handles and descriptors.
The attributes for OCI handles and descriptors can be read with OCIAttrGet() and
modified with OCIAttrSet().

34.2.1 Conventions
For each handle type, the attributes that can be read or changed are listed.
Each attribute listing includes the following information:
Mode
The following modes are valid:
READ - The attribute can be read using OCIAttrGet().
WRITE - The attribute can be modified using OCIAttrSet().
READ/WRITE - The attribute can be read using OCIAttrGet(), and it can be modified
using OCIAttrSet().
Description
This is a description of the purpose of the attribute.
Attribute Data Type
This is the data type of the attribute. If necessary, a distinction is made between the
data type for READ and WRITE modes.

34.2.2 Server Handle Attributes
Lists the server handle attributes.
The following server handle attributes are available:
•

OCI_ATTR_XSTREAM_ACK_INTERVAL

•

OCI_ATTR_XSTREAM_IDLE_TIMEOUT

34.2.2.1 OCI_ATTR_XSTREAM_ACK_INTERVAL
Describes the OCI_ATTR_XSTREAM_ACK_INTERVAL server handle attribute.
Mode
READ/WRITE

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Description
For XStream Out, the ACK interval is the minimum interval in seconds that the
outbound server receives the processed low position from the client application. After
each ACK interval, the outbound server ends any in-progress
OCIXStreamOutLCRReceive() or OCIXStreamOutLCRCallbackReceive() call so that the
processed low position cached at the client application can be sent to the outbound
server.
For XStream In, the ACK interval is the minimum interval in seconds that the inbound
server sends the processed low position to the client application. After each ACK
interval, any in-progress OCIXStreamInLCRSend() or OCIXStreamInLCRCallbackSend() call
is terminated for the inbound server to send a new processed low position to the client
application.
The default value for OCI_ATTR_XSTREAM_ACK_INTERVAL is 30 seconds. This attribute is
checked only during the OCIXStreamOutAttach() or OCIXStreamInAttach() calls. Thus, it
must be set before invoking these APIs; otherwise, the default value is used.
Attribute Data Type
ub4 */ub4

34.2.2.2 OCI_ATTR_XSTREAM_IDLE_TIMEOUT
Describes the OCI_ATTR_XSTREAM_IDLE_TIMEOUT server handle attribute.
Mode
READ/WRITE

Description
The idle timeout is the number of seconds of idle the outbound server waits for an
LCR before terminating the OCIXStreamOutLCRReceive() or
OCIXStreamOutLCRCallbackReceive() call.
The default for OCI_ATTR_XSTREAM_IDLE_TIMEOUT is one second. This attribute is checked
only during the OCIXStreamOutAttach() or OCIXStreamInAttach() call. Thus, it must be
set before invoking these APIs; otherwise, the default value is used.
Attribute Data Type
ub4 */ub4

34-4

35
OCI XStream Functions
This chapter describes the XStream functions for OCI.
A row logical change record (LCR) is used to encapsulate each row change. It
includes the schema name, table name, DML operation, and the column values. For
update operations, both before and after column values are included. The column data
is in the format specified by the "Program Variable" column in Table 35-3. Character
columns are converted to the client's character set.
A DDL LCR is used to encapsulate each DDL change. It includes the object name, the
DDL text, and the DDL command, for example, ALTER TABLE or TRUNCATE TABLE. See
Table A-1 for a list of DDL command codes.

See Also:
Oracle Database Globalization Support Guide for more information about
NLS settings.
XStream sample programs are found in xstream/oci under the $ORACLE_HOME/
demo directory.

Each LCR also has a transaction ID and position. For transactions captured outside
Oracle databases, any byte-comparable RAW array can be used as the LCR position, if
the position of each LCR in the stream is strictly increasing.
This chapter contains the topic:
•

About Using the XStream Interface

•

Introduction to XStream Functions

•

OCI XStream Functions

35.1 About Using the XStream Interface
Since Oracle Database 11g Release 2, Oracle Streams provides enhanced APIs,
known as eXtended Streams (XStream) Out and XStream In, to enable high
performance, near real-time information-sharing infrastructure between Oracle
databases and non-Oracle databases, non-RDBMS Oracle products, file systems,
third party software applications, and so on.
XStream is built on top of Streams infrastructure.
This section includes the following topics:
•

XStream Out

•

XStream In

•

Security of XStreams

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About Using the XStream Interface

See Also:
OCI XStream Functions

35.1.1 XStream Out
XStream Out allows a remote client to attach to an outbound server (a Streams apply
process) and extract row changes in the form of Logical Change Records (LCRs).
To use XStream Out, a capture and an apply process must be created similar to other
Streams setup. All data types supported by Oracle Streams including LOB, LONG, and
XMLType are supported by XStreams. Such an apply process is called an outbound
server. The capture and the outbound server may or may not be on the same
database instance. After the capture and the outbound server have started, row
changes will be captured and sent to the outbound server. An external client can then
connect to this outbound server using OCI. After the connection is established, the
client can loop waiting for LCRs from the outbound server. The client can register a
client-side callback to be invoked each time an LCR is received. At anytime, the client
can detach from the outbound server as needed. Upon restart, the outbound server
knows where in the redo stream to start streaming LCRs to the client.
This section includes the following topics:
•

LCR Streams

•

The Processed Low Position and Restart Considerations

See Also:
•

Oracle Streams Concepts and Administration for the basics of LCRs

•

Oracle Database XStream Guide for more details of XStreams concepts

35.1.1.1 LCR Streams
Describes characteristics of an LCR stream.
•

An LCR stream must be repeatable.

•

An LCR stream must contain a list of assembled and committed transactions.

•

LCRs from one transaction are contiguous. There is no interleaving of transactions
in the LCR stream.

•

Each transaction within an LCR stream must have an ordered list of LCRs and a
transaction ID.

•

The last LCR in each transaction must be a commit LCR.

•

Each LCR must have a unique position.

•

The position of all LCRs within a single transaction and across transactions must
be strictly increasing.

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35.1.1.2 The Processed Low Position and Restart Considerations
If the outbound server or the client aborts abnormally, the connection between the two
is automatically broken. The client needs to maintain the processed low position to
properly recover after a restart.
The processed low position is a position below which all LCRs have been processed
by the client. This position should be maintained by the client while applying each
transaction. Periodically this position is sent to the server while the client executes
XStream Out APIs. This position indicates to the server that the client has processed
all LCRs below or equal to this position; thus, the server can purge redo logs that are
no longer needed.
Upon restart, the client must re-attach to the outbound server. During the attach call,
the client can notify the outbound server of the last position received by the client. The
outbound server then sends LCRs with position greater than this last position. If the
client does not specify the last position (that is, a NULL is specified), the outbound
server will retrieve the processed low position from its system tables and derive the
starting position to mine the redo logs. It will send to the client the LCRs with position
greater than this processed low position.

35.1.2 XStream In
To replicate non-Oracle data into Oracle databases use XStream In which allows a
remote client to attach to an inbound server (a Streams apply process) and send row
and DDL changes in the form of LCRs.
An external client application connects to the inbound server using OCI. After the
connection is established, the client application acts as the capture agent for the
inbound server by streaming LCRs to it. A client application can attach to only one
inbound server per database connection. Each inbound server only allows one client
attaching to it.
XStream In uses the following features of Oracle Streams:
•

High performance processing of DML changes using an apply process and,
optionally, apply process parallelism.

•

Apply process features such as SQL generation, conflict detection and resolution,
error handling, and customized processing with apply handlers.

•

Streaming network transmission of information with minimal network round trips.

XStream In supports all of the data types that are supported by Oracle Streams,
including LOBs, LONG, LONG RAW, and XMLType. A client application sends LOB and
XMLType data to the inbound server in chunks. Several chunks make up a single column
value of LOB or XMLType.
This section includes the following topics:
•

Processed Low Position and Restart Ability

•

Stream Position

35.1.2.1 Processed Low Position and Restart Ability
The processed low position is the position below which the inbound server no longer
requires any LCRs.

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This position corresponds with the oldest SCN for an Oracle Streams apply process
that applies changes captured by a capture process.
The processed low position indicates that the LCRs less than or equal to this position
have been processed by the inbound server. If the client re-attaches to the inbound
server, it only needs to send LCRs greater than the processed low position because
the inbound server discards any LCRs that are less than or equal to the processed low
position.
If the client application aborts abnormally, then the connection between the client
application and the inbound server is automatically broken. Upon restart, the client
application retrieves the processed low position from the inbound server and instructs
its capture agent to retrieve changes starting from this processed low position.
To limit the recovery time of a client application using the XStream In interface, the
client application can send activity, such as empty transactions, periodically to the
inbound server. When there are no LCRs to send to the server, the client can send a
row LCR with a commit directive to advance the inbound server's processed low
position. This activity acts as an acknowledgement so that the inbound server's
processed low position can be advanced. The LCR stream sent to an inbound server
must follow the LCR stream properties for XStream Out defined above.

35.1.2.2 Stream Position
Stream position refers to the position of an LCR in a given LCR stream.
For transactions captured outside Oracle databases the stream position must be
encoded in certain format (for example, base-16 encoding) that supports byte
comparison. The stream position is key to the total order of transaction stream sent by
clients using the XStream In interface.

35.1.3 Security of XStreams
Describes the security characteristics of XStreams.
XStream Out allows regular users to receive LCRs without requiring system level
privileges. System level privileges, such as DBA role, are required to configure
XStream Out. The user who configures XStream Out can specify a regular user as the
connect user who can attach to an outbound server to receive LCRs.
XStream In allows regular users to update tables in its own schema without requiring
system level privileges (for example, DBA) to configure XStream In.
XStream cannot assume that the connected user to the inbound or outbound server is
trusted.
OCI clients must connect to an Oracle database prior to attaching to an XStream
outbound or inbound server created on that database. The connected user must be
the same as the connect_user configured for the attached outbound server or the
apply_user configured for the attached inbound server; otherwise, an error is raised.

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See Also:
Oracle Database XStream Guide for more about configuring Oracle
XStreams

35.2 Introduction to XStream Functions
Lists and describes the conventions used to describe the functions.
These conventions include:
•

Conventions for OCI Functions — For each function, the following information is
listed:

•

Purpose — A brief description of the action performed by the function.

•

Syntax — The function declaration.

•

Parameters — A description of each of the function's parameters. This includes
the parameter's mode. The mode of a parameter has three possible values, as
described in the following table.
Table 35-1

•

Mode of a Parameter

Mode

Description

IN

A parameter that passes data to the OCI.

OUT

A parameter that receives data from the OCI on this call.

IN/OUT

A parameter that passes data on the call and receives data on
the return from this or a subsequent call.

Comments — More detailed information about the function (if available), which can
include return values, restrictions on the use of the function, examples, or other
information that can be useful when using the function in an application.

35.3 OCI XStream Functions
Lists and describes OCI XStream Functions.
This section and Table 35-2 describe the OCI XStream functions.
Table 35-2

OCI XStream Functions

Function

Purpose

LCR Functions

To get and set one or more values of an
LCR. Note: These calls do not require a
server round-trip.

OCILCRAttributesGet()

Gets extra attribute information in (ROW
or DDL) LCR.

OCILCRAttributesSet()

Populates extra attribute information in
ROW or DDL LCR.

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Table 35-2

(Cont.) OCI XStream Functions

Function

Purpose

OCILCRComparePosition()

Compares two position LCRID values.

OCILCRConvertPosition()

Converts an LCRID value to the
specified version (1 or 2).

OCILCRFree()

Frees the LCR

OCILCRHeaderGet()

Returns the common header fields for a
ROW or DDL LCR

OCILCRHeaderSet()

Initializes the common header fields for
a ROW or DDL LCR

OCILCRDDLInfoGet()

Retrieves specific fields in a DDL LCR

OCILCRDDLInfoSet()

Populates DDL-specific fields in a DDL
LCR

OCILCRLobInfoGet()

Returns the LOB information for a piecewise LOB LCR

OCILCRLobInfoSet()

Sets the LOB information for a piecewise LOB LCR

OCILCRNew()

Constructs a new LCR object of the
specified type (row or DDL) for the given
duration

OCILCRRowColumnInfoGet()

Returns the column fields in a row LCR

OCILCRRowColumnInfoSet()

Populates column fields in a row LCR

OCILCRRowStmtGet()

Returns the generated SQL statement
for the row LCR, with values in-lined

OCILCRRowStmtWithBindVarGet()

Returns the generated SQL statement,
which uses bind variables for column
values

OCILCRSCNsFromPosition()

Gets the SCN and commit SCN from a
position value

OCILCRSCNToPosition()

Converts SCN to position

OCILCRWhereClauseGet()

Gets the WHERE clause statement for the
given row LCR

OCILCRWhereClauseWithBindVarGet()

Gets the WHERE clause statement with
bind variables for the given row LCR

XStream In Functions

To send an LCR stream to an XStream
inbound server

OCIXStreamInAttach()

Attaches to an inbound server

OCIXStreamInChunkSend()

Sends chunk data to the inbound server

OCIXStreamInCommit()

Commits the given transaction

OCIXStreamInDetach()

Detaches from the inbound server

OCIXStreamInErrorGet()

Returns the first error encountered by
the inbound server since the attach call

OCIXStreamInFlush()

Flushes the network while attaching to
an XStream inbound server

OCIXStreamInLCRCallbackSend()

Sends the LCR stream to the attached
inbound server using callbacks

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Table 35-2

(Cont.) OCI XStream Functions

Function

Purpose

OCIXStreamInLCRSend()

Sends the LCR stream to the attached
inbound server using callbacks

OCIXStreamInProcessedLWMGet()

Gets the local processed low position

OCIXStreamInSessionSet()

Sets session attributes for XStream In
functions

XStream Out Functions

To receive an LCR stream from an
XStream outbound server

OCIXStreamOutAttach()

Attaches to an outbound server

OCIXStreamOutChunkReceive()

Retrieves data of each LOB or LONG or
XMLType column one chunk at a time

OCIXStreamOutDetach()

Detaches from the outbound server

OCIXStreamOutLCRCallbackReceive()

Gets the LCR stream from the outbound
server using callbacks

OCIXStreamOutLCRReceive()

Receives an LCR stream from an
outbound server without using callbacks

OCIXStreamOutProcessedLWMSet()

Updates the local copy of the processed
low-water mark

OCIXStreamOutSessionSet()

Sets session attributes for XStream Out
functions

35.3.1 OCILCRAttributesGet()
Gets extra attribute information in (ROW or DDL) LCR.
Purpose
It gets any extra non-first class attributes that are not populated through
OCILCRHeaderGet(), OCILCRDDLInfoGet(), or OCILCRProcedureInfoGet(), for example,

edition name.
Syntax
sword OCILCRAttributesGet (

OCISvcCtx
OCIError
ub2
oratext
ub2
ub2
void
OCIInd
ub2
void
ub2
ub4

*svchp,
*errhp,
*num_attrs,
**attr_names,
*attr_namesl,
*attr_dtyp,
**attr_valuesp,
*attr_indp,
*attr_alensp,
*lcrp,
array_size,
mode );

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Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
num_attrs (OUT)
Number of extra attributes.
attr_names (OUT)
An array of extra attribute name pointers.
attr_namesl (OUT)
An array of extra attribute name lengths.
attr_dtyp (OUT)
An array of extra attribute data types. Valid data types: see Comments.
attr_valuesp (OUT)
An array of extra attribute data value pointers.
attr_indp (OUT)
An indicator array. Each returned element is an OCIInd value (OCI_IND_NULL or
OCI_IND_NOTNULL).
attr_alensp (OUT)
An array of actual extra attribute data lengths. Each element in alensp is the length in
bytes.
lcrp (IN)
Pointer to ROW or DDL LCR.
array_size (IN)
Size of the array argument in the other parameters. If array_size is not large enough
to accommodate the number of attributes in the requested attribute list, then OCI_ERROR
is returned. Parameter num_attrs returns the expected size.
mode (IN)
Specify OCI_DEFAULT.
Comments
The valid data types for attr_dtyp are:
SQLT_CHR
SQLT_INT
SQLT_RDD

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35.3.2 OCILCRAttributesSet()
Populates extra attribute information in ROW or DDL LCR.
Purpose
It populates any extra non-first class attributes that cannot be set through
OCILCRHeaderSet(), OCILCRDDLInfoSet(), or OCILCRRowColumnInfoSet(), for example,
edition name.
Syntax
sword OCILCRAttributesSet (

OCISvcCtx *svchp,
OCIError
*errhp,
ub2
num_attrs,
oratext
**attr_names,
ub2
*attr_names_lens,
ub2
*attr_dtyp,
void
**attr_valuesp,
OCIInd
*attr_indp,
ub2
*attr_alensp,
void
*lcrp,
ub4
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
num_attrs (IN)
Number of extra attributes.
attr_names (IN)
Pointer to an array of extra attribute names. Attribute names must be canonicalized.
attr_names_lens (IN)
Pointer to an array of extra attribute name lengths.
attr_dtyp (IN)
Pointer to an array of extra attribute data types. See valid data types in Comments of
OCILCRRowColumnInfoSet().
attr_valuesp (IN)
Address of an array of extra attribute data values.
attr_indp (IN)
Pointer to an indicator array. For all data types, this is a pointer to an array of OCIInd
values (OCI_IND_NULL or OCI_IND_NOTNULL).
attr_alensp (IN)
Pointer to an array of actual extra attribute data lengths. Each element in attr_lensp is
the length in bytes.

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lcrp (IN/OUT)
Pointer to a ROW or DDL LCR.
mode (IN)
Specify OCI_DEFAULT.
Comments
Valid attributes are:
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_ATTR_THREAD_NO
OCI_LCR_ATTR_ROW_ID
OCI_LCR_ATTR_SESSION_NO
OCI_LCR_ATTR_SERIAL_NO
OCI_LCR_ATTR_USERNAME
OCI_LCR_ATTR_TX_NAME
OCI_LCR_ATTR_EDITION_NAME
OCI_LCR_ATTR_MESSAGE_TRACKING_LABEL
OCI_LCR_ATTR_CURRENT_USER
OCI_LCR_ATTR_ROOT_NAME

"THREAD#"
"ROW_ID"
"SESSION#"
"SERIAL#"
"USERNAME"
"TX_NAME"
"EDITION_NAME"
"MESSAGE_TRACKING_LABEL"
"CURRENT_USER"
"ROOT_NAME"

Related Topics
•

OCILCRRowColumnInfoSet()
Populates column fields in a row LCR.

35.3.3 OCILCRComparePosition()
Compares two position LCRID values.
Purpose
These LCRIDs can have different versions. The provided position must be a valid
LCRID for Oracle Database 12c Release 2 (12.2).
Syntax
sword OCILCRComparePosition(OCISvcCtx *svchp,
OCIError *errhp,
ub1
*position1,
ub2
position1_len,
ub1
*position2,
ub2
position2_len,
ub4
mode,
sb2
*result);

Parameters
svchp (IN)
OCI service context.
errhp (IN)
OCI Error handle.
position1 (IN)
The first position value to compare.

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position1_len (IN)
The length of position1.
position2 (IN)
The second position value to compare.
position2_len (IN)
The length of position2.
mode (IN)
The mode flags.
result (OUT)
0 if both values are equal.
-1 if position1 is less than position2.
1 if position1 is greater than position2.

Returns
OCI_SUCCESS if the conversion succeeds, OCI_ERROR otherwise.

Usage Notes
Supported modes are:
•

0 - Complete byte comparison.

•

2 - Smaller length is smaller value

35.3.4 OCILCRConvertPosition()
Converts an LCRID value to the specified version (1 or 2).
Purpose
The provided LCRID must be valid for Oracle Database 12c Release 2 (12.2).
Syntax
sword OCILCRConvertPosition(OCISvcCtx *svchp,
OCIError *errhp,
ub1
*in_position,
ub2
in_position_len,
ub1
*out_position,
ub2
*out_position_len,
ub1
to_version,
ub4
mode);

Parameters
svchp (IN)
OCI service context.
errhp (IN)
OCI Error handle.
in_position (IN)
The position value to convert.

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in_position_len (IN)
The length of in_position.
out_position (OUT)
The result position value (in the specified version). The memory must be preallocated.
out_position_len (OUT)
The length of out_position.
to_version (IN)
The version to which to convert to. The value 1 should be specified for the original
OCI_LCRID_V1 format. The value 2 should be specified for the OCI_LCRID_V2 format.
#define OCI_LCRID_V1
#define OCI_LCRID_V2

1
2

mode (IN)
The mode flags.
Returns
OCI_SUCCESS if the conversion succeeds.
OCI_SUCCESS if the LCRID is already in the desired version.
OCI_ERROR if the conversion fails.

Usage Notes
None.

35.3.5 OCILCRFree()
Frees the LCR.
Purpose
Frees the LCR.
Syntax
sword OCILCRFree ( OCISvcCtx
OCIError
void
ub4

*svchp,
*errhp,
*lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
lcrp (IN/OUT)
Streams LCR pointer.

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mode (IN)
Specify OCI_DEFAULT.

35.3.6 OCILCRDDLInfoGet()
Retrieves specific fields in a DDL LCR.
Purpose
Retrieves specific fields in a DDL LCR.
Syntax
sword OCILCRDDLInfoGet ( OCISvcCtx
OCIError
oratext
ub2
oratext
ub4
oratext
ub2
oratext
ub2
oratext
ub2
oratext
ub2
oraub8
void
ub4

*svchp,
*errhp,
**object_type,
*object_type_len,
**ddl_text,
*ddl_text_len,
**logon_user,
*logon_user_len,
**current_schema,
*current_schema_len,
**base_table_owner,
*base_table_owner_len,
**base_table_name,
*base_table_name_len,
*flag,
*ddl_lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
object_type (OUT)
The type of object on which the DDL statement was executed. (See
OCILCRDDLInfoSet().) Optional. If not NULL, then both object_type and
object_type_len arguments must not be NULL.
object_type_len (OUT)
Length of the object_type string without the NULL terminator.
ddl_text (OUT)
The text of the DDL statement. Optional. If not NULL, then both ddl_text and
ddl_text_len arguments must not be NULL.
ddl_text_len (OUT)
DDL text length in bytes without the NULL terminator.

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logon_user (OUT)
Canonicalized (follows a rule or procedure) name of the user whose session executed
the DDL statement. Optional. If not NULL, then both logon_user and logon_user_len
arguments must not be NULL.
logon_user_len (OUT)
Length of the logon_user string without the NULL terminator.
current_schema (OUT)
The canonicalized schema name that is used if no schema is specified explicitly for
the modified database objects in ddl_text. Optional. If not NULL, then both
current_schema and current_schema_len arguments must not be NULL.
current_schema_len (OUT)
Length of the current_schema string without the NULL terminator.
base_table_owner (OUT)
If the DDL statement is a table-related DDL (such as CREATE TABLE and ALTER TABLE), or
if the DDL statement involves a table (such as creating a trigger on a table), then
base_table_owner specifies the canonicalized owner of the table involved. Otherwise,
base_table_owner is NULL. Optional. If not NULL, then both base_table_owner and
base_table_owner_len arguments must not be NULL.
base_table_owner_len (OUT)
Length of the base_table_owner string without the NULL terminator.
base_table_name (OUT)
If the DDL statement is a table-related DDL (such as CREATE TABLE and ALTER TABLE), or
if the DDL statement involves a table (such as creating a trigger on a table), then
base_table_name specifies the canonicalized name of the table involved. Otherwise,
base_table_name is NULL. Optional. If not NULL, then both base_table_name and
base_table_name_len arguments must not be NULL.
base_table_name_len (OUT)
Length of the base_table_name string without the NULL terminator.
flag (OUT)
DDL LCR flag. Optional. Data not returned if argument is NULL. Future extension not
used currently.
ddl_lcrp (IN)
DDL LCR. Cannot be NULL.
mode (IN)
Specify OCI_DEFAULT.
Related Topics
•

OCILCRDDLInfoSet()
Populates DDL-specific fields in a DDL LCR.

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35.3.7 OCILCRHeaderGet()
Returns the common header fields for ROW or DDL LCR.
Purpose
All returned pointers point directly to the corresponding LCR fields.
Syntax
sword OCILCRHeaderGet ( OCISvcCtx
OCIError
oratext
ub2
oratext
ub2
oratext
ub2
oratext
ub2
ub1
ub2
oratext
ub2
OCIDate
ub2
ub2
ub1
ub2
oraub8
void
ub4

*svchp,
*errhp,
**src_db_name,
*src_db_name_len,
**cmd_type,
*cmd_type_len,
**owner,
*owner_len,
**oname,
*oname_len,
**tag,
*tag_len,
**txid,
*txid_len,
*src_time,
*old_columns,
*new_columns,
**position,
*position_len,
*flag,
*lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
src_db_name (OUT)
Canonicalized source database name. Must be non-NULL.
src_db_name_len (OUT)
Length of the src_db_name string in bytes excluding the NULL terminator.
cmd_type (OUT)
For row LCRs: One of the following values:

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Note:
The values, #define OCI_LCR_ROW_CMD_ROLLBACK and #define
OCI_LCR_ROW_CMD_START_TX, is functionality that is available starting with
Oracle Database 11g Release 2 (11.2.0.2).
#define
#define
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_ROW_CMD_INSERT
OCI_LCR_ROW_CMD_DELETE
OCI_LCR_ROW_CMD_UPDATE
OCI_LCR_ROW_CMD_COMMIT
OCI_LCR_ROW_CMD_ROLLBACK
OCI_LCR_ROW_CMD_START_TX
OCI_LCR_ROW_CMD_LOB_WRITE
OCI_LCR_ROW_CMD_LOB_TRIM
OCI_LCR_ROW_CMD_LOB_ERASE

For DDL LCRs: One of the command types in OCI_ATTR_SQLFNCODE.
cmd_type_len (OUT)
Length of the cmd_type string in bytes excluding the NULL terminator.
owner (OUT)
Canonicalized table owner name. Must be non-NULL. For procedure LCRs, the
package or procedure owner is returned in owner.
owner_len (OUT)
Length of the owner string in bytes excluding the NULL terminator.
oname (OUT)
Canonicalized table name. Must be non-NULL. For procedure LCRs, the procedure
name is returned in oname.
oname_len (OUT)
Length of the oname string in bytes excluding the NULL terminator.
tag (OUT)
A binary tag that enables tracking of the LCR. For example, you can use this tag to
determine the original source database of the DML statement if apply forwarding is
used.
tag_len (OUT)
Number of bytes in the tag.
txid (OUT)
Transaction ID. Must be non-NULL
txid_len (OUT)
Length of the string in bytes excluding the NULL terminator.
src_time (OUT)
The time when the change was generated in the redo log file of the source database.
old_columns (OUT)
Number of columns in the OLD column list. Returns 0 if the input LCR is a DDL LCR.
Optional.

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new_columns (OUT)
Number of columns in the NEW column list. Returns 0 if the input LCR is a DDL LCR.
Optional.
position (OUT)
Position for LCR.
position_len (OUT)
Length of position.
flag (OUT)
LCR flag. Possible flags are listed in Comments.
lcrp (IN)
lcrp cannot be NULL.
mode (IN)
OCILCR_NEW_ONLY_MODE - If this mode is specified, then the new_columns returned is the
count of the columns in the NEW column list only. Otherwise, the new_columns returned
is the number of distinct columns present in either the NEW or the OLD column list of the

given row LCR.
OCI_LCR_APPCON_REPLAY - If this mode is specified, then it indicates the LCR is replayed
from the application container sync statement.

Comments
LCR flag.
#define OCI_ROWLCR_HAS_ID_KEY_ONLY /* only has ID key cols */
#define OCI_ROWLCR_SEQ_LCR
/* sequence lcr */
OCILCRProcedureInfoGet() can be called to get the package name.

35.3.8 OCILCRRowStmtGet()
Returns the generated SQL statement for the row LCR, with values in-lined.
Purpose
Users must preallocate the memory for sql_stmt, and *sql_stmt_len must be set to the
size of the allocated buffer, when it is passed in. If *sql_stmt_len is not large enough to
hold the generated SQL statement, then an error is raised.
Syntax
sword OCILCRRowStmtGet ( OCISvcCtx
OCIError
oratext
ub4
void
ub4

*svchp,
*errhp,
*row_stmt,
*row_stmt_len,
*row_lcrp,
mode );

Parameters
svchp (IN)
Service handle context.

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errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
row_stmt (IN/OUT)
The generated SQL statement for the row LCR.
row_stmt_len (IN/OUT)
Set to the size of the allocated buffer for row_stmt when passed in; returns the length
of row_stmt.
row_lcrp (IN)
Pointer to row LCR.
mode (IN)
Specify OCI_DEFAULT.

35.3.9 OCILCRRowStmtWithBindVarGet()
Returns the generated SQL statement, which uses bind variables for column values.
Purpose
The values for the bind variables are returned separately in arrays. You must
preallocate the memory for sql_stmt and the arrays, *sql_stmt_len must be set to the
size of the allocated buffer, and array_size must be the length of the arrays. The actual
column values in bind_var_valuesp points to the values inside the LCR, so it is a
shallow copy. If array_size is not large enough to hold all the variables, or if
*sql_stmt_len is not large enough to hold the generated SQL statement, then an error
is raised.
Syntax
sword OCILCRRowStmtWithBindVarGet ( OCISvcCtx
OCIError
oratext
ub4
ub2
ub2
void
OCIInd
ub2
ub1
ub1
void
oratext
ub2
oraub8
ub2
oratext
ub4

*svchp,
*errhp,
*row_stmt,
*row_stmt_len,
*num_bind_var,
*bind_var_dtyp,
**bind_var_valuesp,
*bind_var_indp,
*bind_var_alensp,
*bind_var_csetidp,
*bind_var_csetfp,
*row_lcrp,
**chunk_column_names,
*chunk_column_namesl,
*chunk_column_flags,
array_size,
*bind_var_syntax,
mode );

Parameters
svchp (IN)
Service handle context.

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errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
row_stmt (IN/OUT)
The generated SQL statement for the row LCR.
row_stmt_len (IN/OUT)
Set to the size of the allocated buffer for row_stmt when passed in; returns the length
of row_stmt.
num_bind_var (OUT)
The number of bind variables.
bind_var_dtyp (IN/OUT)
Array of data types for the bind variables.
bind_var_valuesp (IN/OUT)
Array of values for the bind variables.
bind_var_indp (IN/OUT)
Array of NULL indicators for the bind variables.
bind_var_alensp (IN/OUT)
Array of lengths for the bind variable values.
bind_var_csetidp (IN/OUT)
Array of character set IDs for the bind variables.
bind_var_csetfp (IN/OUT)
Array of character set forms for the bind variables.
row_lcrp (IN)
Pointer to row LCR.
chunk_column_names (OUT)
Array of LOB column names in LCR.
chunk_column_namesl (OUT)
Array of LOB column name lengths.
chunk_column_flags (OUT)
Array of LOB column flags. Possible flags are listed in Comments.
array_size (IN)
Size of each of the parameter arrays.
bind_var_syntax (IN)
Either (:) (binds are of the form :1, :2, and so on.) or (?) (binds are of the form (?)).
mode (IN)
Specify OCI_DEFAULT.
Comments
The following LCR column flags can be combined using bitwise OR operator.

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#define
#define
#define
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_COLUMN_LOB_DATA
OCI_LCR_COLUMN_LONG_DATA
OCI_LCR_COLUMN_EMPTY_LOB
OCI_LCR_COLUMN_LAST_CHUNK
OCI_LCR_COLUMN_AL16UTF16
OCI_LCR_COLUMN_NCLOB
OCI_LCR_COLUMN_XML_DATA
OCI_LCR_COLUMN_XML_DIFF
OCI_LCR_COLUMN_ENCRYPTED
OCI_LCR_COLUMN_UPDATED

/*
/*
/*
/*
/*
/*
/*
/*
/*
/*

column contains LOB data */
column contains long data */
column has an empty LOB */
last chunk of current column */
column is in AL16UTF16 fmt */
column has NCLOB data */
column contains xml data */
column contains xmldiff data */
column is encrypted */
col is updated */

/* OCI_LCR_COLUMN_UPDATED is set only for the modified columns in the NEW
* column list of an update LCR.
*/

35.3.10 OCILCRNew()
Constructs a new Streams LCR object of the specified type (ROW or DDL) for the
given duration.
Purpose
Constructs a new Streams LCR object of the specified type (ROW or DDL) for the
given duration.
Syntax
sword OCILCRNew ( OCISvcCtx
OCIError
OCIDuration
ub1
void
ub4

*svchp,
*errhp,
duration,
lcrtype,
**lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
duration (IN)
Memory for the LCR is allocated for this specified duration.
lcrtype (IN)
LCR type. Values are:
#define OCI_LCR_XROW
#define OCI_LCR_XDDL

lcrp (IN/OUT)
If *lcrp is not NULL, an error is raised.
mode (IN)
Specify OCI_DEFAULT.

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Comments
Note:
•

After creation, you are not allowed to change the type of the LCR (ROW or DDL)
or duration of the memory allocation.

•

Use OCILCRHeaderSet() to populate common header fields for row or DDL LCR.

•

After the LCR header is initialized, use OCILCRRowColumnInfoSet() or
OCILCRDDLInfoSet() to populate operation specific elements. Use
OCILCRExtraAttributesSet() to populate extra attribute information.

•

Use OCILCRFree() to free the LCR created by this function.

35.3.11 OCILCRRowColumnInfoGet()
Returns the column fields in a row LCR.
Purpose
Returns the column fields in a row LCR.
Syntax
sword OCILCRRowColumnInfoGet ( OCISvcCtx
OCIError
ub2
ub2
oratext
ub2
ub2
void
OCIInd
ub2
ub1
oraub8
ub2
void
ub2
ub4

*svchp,
*errhp,
column_value_type,
*num_columns,
**column_names,
*column_name_lens,
*column_dtyp,
**column_valuesp,
*column_indp,
*column_alensp,
*column_csetfp,
*column_flags,
*column_csid,
*row_lcrp,
array_size,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
column_value_type (IN)
ROW LCR column value type; either of:
#define OCI_LCR_ROW_COLVAL_OLD
#define OCI_LCR_ROW_COLVAL_NEW

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num_columns (OUT)
Number of columns in the specified column array.
column_names (OUT)
An array of column name pointers.
column_name_lens (OUT)
An array of column name lengths.
column_dtyp (OUT)
An array of column data types. Optional. Data is not returned if column_dtyp is NULL.
column_valuesp (OUT)
An array of column data pointers.
column_indp (OUT)
An array of indicators.
column_alensp (OUT)
An array of column lengths. Each returned element is the length in bytes.
column_csetfp (OUT)
An array of character set forms for the columns. Optional. Data is not returned if the
argument is NULL.
column_flags (OUT)
An array of column flags. Optional. Data is not returned if the argument is NULL. See
Comments for the values.
column_csid (OUT)
An array of character set IDs for the columns.
row_lcrp (IN)
row_lcrp cannot be NULL.

array_size (IN)
Size of each of the parameter arrays. An error is returned if array_size is less than the
number of columns in the requested column list. The actual size of the requested
column list is returned through the num_columns parameter.
mode (IN)
OCILCR_NEW_ONLY_MODE - If this mode is specified, then the new_columns returned is the
count of the columns in the NEW column list only. Otherwise, the new_columns returned
is the number of distinct columns present in either the NEW or the OLD column list of the

given row LCR.
Comments
•

For INSERT, this function must only be called to get the NEW column values.

•

For DELETE, this function must only be called to get the OLD column values.

•

For UPDATE, this function can be called twice, once to get the NEW column values
and once to get the OLD column values.

•

This function must not be called for COMMIT operations.

The following LCR column flags can be combined using bitwise OR operator.

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#define
#define
#define
#define
#define
#define
#define

OCI_LCR_COLUMN_LOB_DATA
OCI_LCR_COLUMN_LONG_DATA
OCI_LCR_COLUMN_EMPTY_LOB
OCI_LCR_COLUMN_LAST_CHUNK
OCI_LCR_COLUMN_AL16UTF16
OCI_LCR_COLUMN_NCLOB
OCI_LCR_COLUMN_XML_DATA

/*
/*
/*
/*
/*
/*
/*

column contains LOB data */
column contains long data */
column has an empty LOB */
last chunk of current column */
column is in AL16UTF16 fmt */
column has NCLOB data */
column contains xml data */

#define OCI_LCR_COLUMN_XML_DIFF

/* column contains xmldiff data */

#define OCI_LCR_COLUMN_ENCRYPTED
#define OCI_LCR_COLUMN_UPDATED

/* column is encrypted */
/* col is updated */

/* OCI_LCR_COLUMN_UPDATED is set only for the modified columns in the NEW
* column list of an update LCR.
*/

Table 35-3 lists the currently supported table column data types. For each data type, it
lists the corresponding LCR column data type, the C program variable type to cast the
LCR column value, and the OCI functions that can manipulate the column values
returned from OCILCRRowColumnInfoGet().
Table 35-3

Table Column Data Types

Table Column
Data Types

LCR Column Data Type

Program Variable

VARCHAR,
NVARCHAR2

SQLT_CHR

char *

NUMBER

SQLT_VNU

OCINumber

Conversion Function

OCINumberToInt()
OCINumberToReal()
OCINumberToText()

DATE

SQLT_ODT

OCIDate

OCIDateToText()
Can access structure directly to get date
and time fields.

RAW

SQLT_BIN

unsigned char *

CHAR, NCHAR

SQL_AFC

char *

BINARY_FLOAT

SQLT_BFLOAT

float

BINARY_DOUBLE

SQLT_BDOUBLE

double

TIMESTAMP

SQLT_TIMESTAMP

OCIDateTime *

OCIDateTimeGetTime()
OCIDateTimeGetDate()
OCIDateTimeGetTimeZoneOffset()
OCIDateTimeToText()

TIMESTAMP WITH
TIME ZONE

SQLT_TIMESTAMP_TZ

OCIDateTime *

OCIDateTimeGetTime()
OCIDateTimeGetDate()
OCIDateTimeGetTimeZoneOffset()
OCIDateTimeToText()

TIMESTAMP WITH
LOCAL TIME ZONE

SQLT_TIMESTAMP_LTZ

OCIDateTime *

OCIDateTimeGetTime()
OCIDateTimeGetDate()
OCIDateTimeGetTimeZoneOffset()
OCIDateTimeToText()

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Table 35-3

(Cont.) Table Column Data Types

Table Column
Data Types

Program Variable

Conversion Function

INTERVAL YEAR TO SQLT_INTERVAL_YM
MONTH

OCIInterval *

OCIIntervalToText()

INTERVAL DAY TO
SECOND

SQLT_INTERVAL_DS

OCIInterval *

UROWID

SQLT_RDD

OCIRowid *

OCIRowidToChar()

CLOB

SQLT_CHR or SQLT_BIN

unsigned char *

1

NCLOB

SQLT_BIN

unsigned char *

1

BLOB

SQLT_BIN

unsigned char *

1

LONG

SQLT_CHR

char *

1

LONG RAW

SQLT_BIN

unsigned char *

1

XMLType

SQLT_CHR or SQLT_BIN

unsigned char *

1

LCR Column Data Type

OCIIntervalGetYearMonth()
OCIIntervalToText()
OCIIntervalGetDaySecond()

Call OCIXStreamOutChunkReceive() to get column data.

35.3.12 OCILCRRowColumnInfoSet()
Populates column fields in a row LCR.
Purpose
Populates column fields in a row LCR.
Syntax
sword OCILCRRowColumnInfoSet ( OCISvcCtx
OCIError
ub2
ub2
oratext
ub2
ub2
void
OCIInd
ub2
ub1
oraub8
ub2
void
ub4

*svchp,
*errhp,
column_value_type,
num_columns,
**column_names,
*column_name_lens,
*column_dtyp,
**column_valuesp,
*column_indp,
*column_alensp,
*column_csetfp,
*column_flags,
*column_csid,
*row_lcrp,
mode );

Parameters
svchp (IN)
Service handle context.

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errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
column_value_type (IN)
ROW LCR Column value types:
#define OCI_LCR_ROW_COLVAL_OLD
#define OCI_LCR_ROW_COLVAL_NEW

num_columns (IN)
Number of columns in each of the array parameters.
column_names (IN)
Pointer to an array of column names. Column names must be canonicalized. Column
names must follow Oracle Database naming conventions and size limitations.
column_name_lens (IN)
Pointer to an array of column name lengths.
column_dtyp (IN)
Pointer to an array of column data types. See Comments for valid data types.
column_valuesp (IN)
Pointer to an array of column data pointers.
column_indp (IN)
Pointer to an indicator array. For all data types, this is a pointer to an array of OCIInd
values (OCI_IND_NULL or OCI_IND_NOTNULL).
column_alensp (IN)
Pointer to an array of actual column lengths in bytes.
column_csetfp (IN)
Pointer to an array of character set forms for the columns. The default form is
SQLCS_IMPLICIT. Setting this attribute causes the database or national character set to
be used on the client side. Set this attribute to SQLCS_NCHAR for the national character
set or SQLCS_IMPLICIT for the database character set. Pass 0 for non-character
columns.
column_flags (IN)
Pointer to an array of column flags. (See Comments for the list of valid LCR column
flags.)
column_csid (IN)
Pointer to an array of character set IDs for the columns.
row_lcrp (IN/OUT)
row_lcrp cannot be NULL.
mode (IN)
Specify OCI_DEFAULT.
Comments
Note:
•

For INSERT, this function must only be called to specify the NEW column values.

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•

For DELETE, this function must only be called to specify the OLD column values.

•

For UPDATE, this function can be called twice, once to specify the NEW column
values and once to specify the OLD column values.

•

This function must not be called for COMMIT operations.

The following LCR column flags can be combined using the bitwise OR operator.
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_COLUMN_LOB_DATA
OCI_LCR_COLUMN_LONG_DATA
OCI_LCR_COLUMN_EMPTY_LOB
OCI_LCR_COLUMN_LAST_CHUNK
OCI_LCR_COLUMN_AL16UTF16
OCI_LCR_COLUMN_NCLOB
OCI_LCR_COLUMN_XML_DATA

/*
/*
/*
/*
/*
/*
/*

column contains LOB data */
column contains long data */
column has an empty LOB */
last chunk of current column */
column is in AL16UTF16 fmt */
column has NCLOB data */
column contains xml data */

#define OCI_LCR_COLUMN_XML_DIFF

/* column contains xmldiff data */

#define OCI_LCR_COLUMN_ENCRYPTED
#define OCI_LCR_COLUMN_UPDATED

/* column is encrypted */
/* col is updated */

/* OCI_LCR_COLUMN_UPDATED is set only for the modified columns in the NEW
* column list of an update LCR.
*/

Valid data types are:
SQLT_AFC
SQLT_DAT
SQLT_BFLOAT
SQLT_BDOUBLE
SQLT_NUM
SQLT_VCS
SQLT_ODT
SQLT_INT
SQLT_BIN
SQLT_CHR
SQLT_RDD
SQLT_VST
SQLT_INT
SQLT_FLT

SQLT_TIMESTAMP
SQLT_TIMESTAMP_TZ
SQLT_TIMESTAMP_LTZ
SQLT_INTERVAL_YM
SQLT_INTERVAL_DS

35.3.13 OCILCRDDLInfoSet()
Populates DDL-specific fields in a DDL LCR.
Purpose
Populates DDL-specific fields in a DDL LCR.
Syntax
sword OCILCRDDLInfoSet ( OCISvcCtx
OCIError
oratext
ub2
oratext
ub4
oratext
ub2

*svchp,
*errhp,
*object_type,
object_type_len,
*ddl_text,
ddl_text_len,
*logon_user,
logon_user_len,

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oratext
ub2
oratext
ub2
oratext
ub2
oraub8
void
ub4

*current_schema,
current_schema_len,
*base_table_owner,
base_table_owner_len,
*base_table_name,
base_table_name_len,
flag,
*ddl_lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
object_type (IN)
The type of object on which the DDL statement was executed. See Comments for the
valid object types.
object_type_len (IN)
Length of the object_type string without the NULL terminator.
ddl_text (IN)
The text of the DDL statement. This parameter must be set to a non-NULL value. DDL
text must be in Oracle Database DDL format.
ddl_text_len (IN)
DDL text length in bytes without the NULL terminator.
logon_user (IN)
Canonicalized name of the user whose session executed the DDL statement.
logon_user_len (IN)
Length of the logon_user string without the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
current_schema (IN)
The canonicalized schema name that is used if no schema is specified explicitly for
the modified database objects in ddl_text. If a schema is specified in ddl_text that
differs from the one specified for current_schema, then the function uses the schema
specified in ddl_text.
This parameter must be set to a non-NULL value.
current_schema_len (IN)
Length of the current_schema string without the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
base_table_owner (IN)
If the DDL statement is a table-related DDL (such as CREATE TABLE or ALTER TABLE), or if
the DDL statement involves a table (such as creating a trigger on a table), then
base_table_owner specifies the canonicalized owner of the table involved. Otherwise,
base_table_owner is NULL.

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base_table_owner_len (IN)
Length of the base_table_owner string without the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
base_table_name (IN)
If the DDL statement is a table-related DDL (such as CREATE TABLE or ALTER TABLE), or if
the DDL statement involves a table (such as creating a trigger on a table), then
base_table_name specifies the canonicalized name of the table involved. Otherwise,
base_table_name is NULL.
base_table_name_len (IN)
Length of the base_table_name without the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
flag (IN)
DDL LCR flag. (Not currently used; used for future extension.) Specify OCI_DEFAULT.
ddl_lcrp (IN/OUT)
ddl_lcrp cannot be NULL.
mode (IN)
Specify OCI_DEFAULT.
Comments
The following are valid object types:
CLUSTER
FUNCTION
INDEX
OUTLINE
PACKAGE
PACKAGE BODY
PROCEDURE
SEQUENCE
SYNONYM
TABLE
TRIGGER
TYPE
USER
VIEW
NULL is also a valid object type. Specify NULL for all object types not listed.

35.3.14 OCILCRGetLCRIDVersion()
Determines the LCRID version of a given position.
Purpose
Determines the LCRID version of a given position.
Syntax
sword OCILCRGetLCRIDVersion(OCISvcCtx
OCIError
ub1
ub2
ub1

*svchp,
*errhp,
*position,
position_len,
*version);

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Parameters
svchp (IN)
The OCI service context.
errhp (IN)
The OCI Error handle.
position (IN)
The position.
position_len (IN)
The length of position.
version (OUT)
The LCRID version for the given input position. A value of 1 should be specified for
the original OCI_LCRID_V1 format. A value of 2 should be specified for the OCI_LCRID_V2
format.
#define OCI_LCRID_V1
#define OCI_LCRID_V2

1
2

Returns
OCI_SUCCESS if the LCRID version is valid, OCI_ERROR otherwise.

Usage Notes
None.

35.3.15 OCILCRHeaderSet()
Initializes the common header fields for ROW or DDL LCR.
Purpose
Initializes the common header fields for row or DDL LCR.
Syntax
sword OCILCRHeaderSet ( OCISvcCtx *svchp,
OCIError *errhp,
oratext
*src_db_name,
ub2
src_db_name_len,
oratext
*cmd_type,
ub2
cmd_type_len,
oratext
*owner,
ub2
owner_len,
oratext
*oname,
ub2
oname_len,
ub1
*tag,
ub2
tag_len,
oratext
*txid,
ub2
txid_len,
OCIDate
*src_time,
ub1
*position,
ub2
position_len,
oraub8
flag,

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void
ub4

*lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
src_db_name (IN)
Canonicalized source database name. Must be non-NULL.
src_db_name_len (IN)
Length of the src_db_name string in bytes excluding the NULL terminator. Must follow
Oracle Database naming conventions and size limitations.
cmd_type (IN)
For row LCRs: One of the following values:

Note:
The values, #define OCI_LCR_ROW_CMD_ROLLBACK and #define
OCI_LCR_ROW_CMD_START_TX, are available starting with Oracle Database 11g
Release 2 (11.2.0.2).
#define
#define
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_ROW_CMD_INSERT
OCI_LCR_ROW_CMD_DELETE
OCI_LCR_ROW_CMD_UPDATE
OCI_LCR_ROW_CMD_COMMIT
OCI_LCR_ROW_CMD_ROLLBACK
OCI_LCR_ROW_CMD_START_TX
OCI_LCR_ROW_CMD_LOB_WRITE
OCI_LCR_ROW_CMD_LOB_TRIM
OCI_LCR_ROW_CMD_LOB_ERASE

For DDL LCRs: One of the command types in OCI_ATTR_SQLFNCODE.
cmd_type_len (IN)
Length of cmd_type.
owner (IN)
Canonicalized table owner name. Owner is not required for COMMIT LCR.
owner_len (IN)
Length of the owner string in bytes excluding the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
oname (IN)
Canonicalized table name. Not required for COMMIT LCR.

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oname_len (IN)
Length of the oname string in bytes excluding the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
tag (IN)
A binary tag that enables tracking of the LCR. For example, you can use this tag to
determine the original source database of the DML statement if apply forwarding is
used.
tag_len (IN)
Number of bytes in the tag. Cannot exceed 2000 bytes.
txid (IN)
Transaction ID. Must be non-NULL.
txid_len (IN)
Length of the txid string in bytes, excluding the NULL terminator. Must follow Oracle
Database naming conventions and size limitations.
src_time (IN)
The time when the change was generated in the online redo log file of the source
database.
position (IN)
Position for LCR. Must be non-NULL and byte-comparable.
position_len (IN)
Length of position. Must be greater than zero.
flag (IN)
LCR flag. Possible flags are listed in Comments.
lcrp (IN/OUT)
lcrp cannot be NULL.

mode (IN)
Specify OCI_DEFAULT.
Comments
Note:
•

This function sets all internal fields of the LCR to NULL including extra attributes.

•

This function does not deep copy the passed-in values. You must ensure data is
valid for the duration of the LCR.

•

For COMMIT LCRs, owner and oname information are not required. Provide valid
values for src_db_name, cmd_type, tag, txid, and position.

•

For ROW LCRs, use OCILCRRowColumnInfoSet() to populate row LCR-specific
column information.

•

For DDL LCRs, use OCILCRDDLInfoSet() to populate DDL operation specific
information.

•

For ROW or DDL LCRs, use OCILCRAttributesSet() to populate extra attribute
information.

The following are LCR flags:

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#define OCI_ROWLCR_HAS_ID_KEY_ONLY /* only has ID key cols */
#define OCI_ROWLCR_SEQ_LCR
/* sequence lcr */

35.3.16 OCILCRLobInfoGet()
Returns the LOB information for a piece-wise LOB LCR generated from a DBMS_LOB or
OCILob procedure.
Purpose
Returns the LOB information for a piece-wise LOB LCR generated from a DBMS_LOB or
OCILob procedure.
Syntax
sword OCILCRLobInfoGet ( OCISvcCtx *svchp,
OCIError
*errhp,
oratext
**column_name,
ub2
*column_name_len,
ub2
*column_dty,
oraub8
*column_flag,
ub4
*offset,
ub4
*size,
void
*row_lcrp,
ub4
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
column_name (OUT)
LOB column name.
column_name_len (OUT)
Length of LOB column name.
column_dty (OUT)
Column data type (either SQLT_CHR or SQLT_BIN).
column_flag (OUT)
Column flag. See Comments in OCILCRRowColumnInfoSet().
offset (OUT)
LOB operation offset in code points. Only returned for LOB WRITE and LOB TRIM
operations. This is the same as the offset parameter for OCILobErase() or the offset
parameter in OCILobWrite().
size (OUT)
LOB operation size in code points. Only returned for LOB TRIM and LOB ERASE
operations. This is the same as the new_length parameter in OCILobTrim() or the amtp
parameter in OCILobErase().

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row_lcrp (IN)
Pointer to a row LCR.
mode (IN)
Specify OCI_DEFAULT.
Comments
Returns OCI_SUCCESS or OCI_ERROR.
Related Topics
•

OCILCRRowColumnInfoSet()
Populates column fields in a row LCR.

35.3.17 OCILCRLobInfoSet()
Sets the LOB information for a piece-wise LOB LCR.
Purpose
This call is valid when the input LCR is a LOB_WRITE, LOB_ERASE, or LOB_TRIM; otherwise,
an error is returned.
Syntax
sword OCILCRLobInfoSet ( OCISvcCtx
OCIError
oratext
ub2
ub2
oraub8
ub4
ub4
void
ub4

*svchp,
*errhp,
*column_name,
column_name_len,
column_dty,
column_flag,
offset,
size,
*row_lcrp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
column_name (IN)
LOB column name.
column_name_len (IN)
Length of LOB column name.
column_dty (IN)
Column data type (either SQLT_CHR or SQLT_BIN).
column_flag (IN)
Column flag. See Comments in OCILCRRowColumnInfoSet().

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offset (IN)
LOB operation offset in code points. Only required for LOB WRITE and LOB TRIM
operations. This is the same as the soffset parameter for OCILobErase() or the offset
parameter in OCILobWrite().
size (IN)
LOB operation size in code points. Only required for LOB TRIM and LOB ERASE
operations.This is the same as the new_length parameter in OCILobTrim() or the amtp
parameter in OCILobErase().
row_lcrp (IN/OUT)
Pointer to a row LCR.
mode (IN)
Specify OCI_DEFAULT.
Comments
Returns OCI_SUCCESS or OCI_ERROR.
Related Topics
•

OCILCRRowColumnInfoSet()
Populates column fields in a row LCR.

35.3.18 OCILCRSCNsFromPosition()
Returns the SCN and the commit SCN from the position value.
Purpose
The input position must be one that is obtained from an XStream outbound server. An
error is returned if the input position does not conform to the expected format.
Syntax
sword OCILCRSCNsFromPosition ( OCISvcCtx
OCIError
ub1
ub2
OCINumber
OCINumber
ub4

*svchp,
*errhp,
*position,
position_len,
*scn,
*commit_scn,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
position (IN)
LCR position value.

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position_len (IN)
Length of LCR position value.
scn (OUT)
SCN number embedded in the given LCR position.
commit_scn (OUT)
The commit SCN embedded in the given position.
mode (IN)
Mode flags used for future expansion. Specify OCI_DEFAULT.
Comments
This function can handle both version 1 and version 2 position (LCRID) values.

35.3.19 OCILCRSCNToPosition()
Converts an SCN to a position.
Purpose
The generated position can be passed as the last_position to OCIXStreamOutAttach()
to filter the LCRs with commit SCN less than the given SCN and the LCR's SCN less
than the given SCN. Therefore, the first LCR sent by the outbound server is either:
•

A commit LCR at the given SCN, or

•

The first LCR of the subsequent transaction with commit SCN greater than or
equal to the given SCN.

Syntax
sword OCILCRSCNToPosition ( OCISvcCtx
OCIError
ub1
ub2
OCINumber
ub4

*svchp,
*errhp,
*position,
*position_len,
*scn,
mode );

Parameters
svchp (IN)
OCI service context.
errhp (IN)
OCI error handle.
position (OUT)
The resulting position. You must preallocate OCI_LCR_MAX_POSITION_LEN bytes.
position_len (OUT)
Length of position.
scn (IN)
The SCN to be stored in position.

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mode (IN)
Mode flags (Not currently used; used for future extension).
Comments
Returns OCI_SUCCESS if the conversion succeeds, OCI_ERROR otherwise.
This function will return a version 1 LCRID.
An error will be raised if the SCN value is larger than the maximum value.

35.3.20 OCILCRScnToPosition2()
Converts SCN to position (LCRID), which can handle both version 1 and version 2.
Purpose
Converts SCN to position (LCRID) for either version 1 or version 2.
Syntax
sword OCILCRSCNToPosition2(OCISvcCtx
OCIError
ub1
ub2
OCINumber
ub1
ub4

*svchp,
*errhp,
*position,
*position_len,
*scn,
version,
mode);

Parameters
svchp (IN)
The OCI service context.
errhp (IN)
The OCI Error handle.
position (OUT)
The result position value (in the specified version) returned. The memory must be
preallocated.
position_len (OUT)
The length of position.
scn (IN)
The SCN value to be stored in position.
version (IN)
The version to which to convert the LCRID value. A value of 1 should be specified for
version 1. A value of 2 should be specified for version 2.
#define OCI_LCRID_V1
#define OCI_LCRID_V2

1
2

mode (IN)
The mode flags (Not currently used; used for future extension)..

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Returns
OCI_SUCCESS if the conversion is successful, OCI_ERROR otherwise.

Usage Notes
If version 1 is specified, and the SCN value is larger than the maximum value, then an
error will be raised.
The given SCN value is assumed to be the commit SCN value.

35.3.21 OCILCRWhereClauseGet()
Gets the WHERE clause statement for the given row LCR.
Purpose
Gets the WHERE clause statement for the given row LCR.
Syntax
sword OCILCRWhereClauseGet ( OCISvcCtx
OCIError
oratext
ub4
void
ub4

*svchp,
*errhp,
*wc_stmt,
*wc_stmt_len,
*row_lcrp,
mode );

Parameters
svchp (IN/OUT)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
wc_stmt (OUT)
SQL statement equivalent to the LCR.
wc_stmt_len (IN/OUT)
Length of the wc_stmt buffer.
row_lcrp (IN)
Row LCR to be converted to SQL.
mode (IN)
Mode flags used for future expansion. Specify OCI_DEFAULT.
Comments
The WHERE clause generated for an INSERT LCR has all the columns that are being
inserted. This WHERE clause could be used to identify the inserted row after it is inserted,
for example, like "returning ROWID".
INSERT INTO TAB(COL1) VALUES (10) -> WHERE COL1=10

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The WHERE clause generated for UPDATE has all the columns in the old column list.
However, the values of the columns are that of the new value if it exists in the new
column list of the UPDATE. If the column does not have a new value, then the old column
value is used.
UPDATE TAB SET COL1 = 10 WHERE COL1 = 20 -> WHERE COL1 = 10
UPDATE TAB SET COL2 = 20 WHERE COL1 = 20 -> WHERE COL1 = 20

The WHERE clause for DELETE uses the columns and values from the old column list.
LOB piecewise operations use the new columns and values for generating the WHERE
clause.
Returns
OCI_SUCCESS or OCI_ERROR.

35.3.22 OCILCRWhereClauseWithBindVarGet()
Gets the WHERE clause statement with bind variables for the given row LCR.
Purpose
Gets the WHERE clause statement with bind variables for the given row LCR.
Syntax
sword OCILCRWhereClauseWithBindVarGet ( OCISvcCtx
OCIError
oratext
ub4
ub2
ub2
void
OCIInd
ub2
ub2
ub1
void
ub2
oratext
ub4

*svchp,
*errhp,
*wc_stmt,
*wc_stmt_len,
*num_bind_var,
*bind_var_dtyp,
**bind_var_valuesp,
*bind_var_indp,
*bind_var_alensp,
*bind_var_csetidp,
*bind_var_csetfp,
*row_lcrp,
array_size,
*bind_var_syntax,
mode );

Parameters
svchp (IN/OUT)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
wc_stmt (OUT)
SQL statement equivalent to the LCR.
wc_stmt_len (IN/OUT)
Length of the wc_stmt buffer.

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num_bind_var (OUT)
Number of bind variables.
bind_var_dtyp (OUT)
Array of data types of bind variables.
bind_var_valuesp (OUT)
Array of values of bind variables.
bind_var_indp (OUT)
Array of NULL indicators of bind variables.
bind_var_alensp (OUT)
Array of lengths of bind values.
bind_var_csetidp (OUT)
Array of char set IDs of binds.
bind_var_csetfp (OUT)
Array of char set forms of binds.
row_lcrp (IN)
Row LCR to be converted to SQL.
array_size (IN)
Size of the array of bind values.
bind_var_syntax (IN)
Native syntax to be used for binds.
mode (IN)
Mode flags for future expansion. Specify OCI_DEFAULT.
Comments
If array_size is not large enough to accommodate the number of columns in the
requested column list, then OCI_ERROR is returned. The expected array_size is returned
through the num_bind_var parameter.
bind_var_syntax for Oracle Database should contain (:). This generates positional
binds such as :1, :2, :3, and so on. For non-Oracle databases input the string that
must be used for binds.

The WHERE clause generated for INSERT LCR has all the columns that are being
inserted. This WHERE clause can identify the inserted row after it is inserted, for
example, like "returning ROWID".
INSERT INTO TAB(COL1) VALUES (10) -> WHERE COL1=10

The WHERE clause generated for UPDATE has all the columns in the old column list.
However, the values of the columns are that of the new column value of the column if
it exists in the new values of the UPDATE. If the column appears only in the old column,
then the old column value is used.
UPDATE TAB SET COL1 = 10 WHERE COL1 = 20 -> WHERE COL1 = 10
UPDATE TAB SET COL2 = 20 WHERE COL1 = 20 -> WHERE COL1 = 20

The WHERE clause for DELETE uses the columns and values from the old column list.

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LOB piecewise operations use the new columns and values for generating the WHERE
clause.
Returns
OCI_SUCCESS or OCI_ERROR.

35.3.23 OCIXStreamInAttach()
Attaches to an inbound server.
Purpose
The client application must connect to the database using a dedicated connection.
Syntax
sword OCIXStreamInAttach ( OCISvcCtx *svchp,
OCIError *errhp,
oratext
*server_name,
ub2
server_name_len,
oratext
*source_name,
ub2
source_name_len,
ub1
*last_position,
ub2
*last_position_len,
ub4
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
server_name (IN)
XStream inbound server name.
server_name_len (IN)
Length of the XStream inbound server name.
source_name (IN)
Source name to identify the data source.
source_name_len (IN)
Source name length.
last_position (OUT)
Last position received by inbound server. Optional. If specified, then you must
preallocate OCI_LCR_MAX_POSITION_LEN bytes for the return value.
last_position_len (OUT)
Length of last_position. Must be non-NULL if last_position is non-NULL.

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mode (IN)
OCIXSTREAM_IN_ATTACH_RESTART_INBOUND - If this mode is specified, then this function can

notify the server to restart the inbound server regardless of whether it is in a disabled
or aborted state. If you do not pass in this mode and the inbound server is in an
aborted state when this call is made, then the function returns an error.
Comments
The name of the inbound server must be provided because multiple inbound servers
can be configured in one Oracle instance. This function returns OCI_ERROR if any error is
encountered while attaching to the inbound server. Only one client can attach to an
XStream inbound server at any time. An error is returned if multiple clients attempt to
attach to the same inbound server or if the same client attempts to attach to multiple
inbound servers concurrently.
This function returns the last position received by the inbound server. Having
successfully attached to the server, the client should resume sending LCRs with
positions greater than this last_position since the inbound server discards all LCRs
with positions less than or equal to the last_position.
Returns either OCI_SUCCESS or OCI_ERROR status code.

35.3.24 OCIXStreamInDetach()
Detaches from the inbound server.
Purpose
Detaches from the inbound server.
Syntax
sword OCIXStreamInDetach ( OCISvcCtx *svchp,
OCIError *errhp,
ub1
*processed_low_position,
ub2
*processed_low_position_len,
ub4
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
processed_low_position (OUT)
The server's processed low position.
processed_low_position_len (OUT)
Length of processed_low_position.
mode (IN)
Specify OCI_DEFAULT.

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Comments
You must pass in a preallocated buffer for the position argument. The maximum length
of this buffer is OCI_LCR_MAX_POSITION_LEN. This position is exposed in
DBA_XSTREAM_INBOUND_PROGRESS view
This call returns the server's processed low position. If this function is invoked while a
OCIXStreamInLCRSend() call is in progress, then it immediately terminates that call
before detaching from the inbound server.
Returns either OCI_SUCCESS or OCI_ERROR status code.

35.3.25 OCIXStreamInLCRSend()
Sends an LCR stream from the client to the attached inbound server.
Purpose
To avoid a network round-trip for every OCIXStreamInLCRSend() call, the connection is
tied to this call and terminates the call after an ACK interval since the LCR stream is
initiated to the server.
Syntax
sword OCIXStreamInLCRSend ( OCISvcCtx
OCIError
void
ub1
oraub8
ub4

*svchp,
*errhp,
*lcrp,
lcrtype,
flag,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
lcrp (IN)
Pointer to the new LCR to send. It cannot be NULL.
lcrtype (IN)
LCR type. Either of:
#define OCI_LCR_XROW
#define OCI_LCR_XDDL

flag (IN)
If bit OCI_XSTREAM_MORE_ROW_DATA (0x01) is set, then LCR contains more chunk data.
You must call OCIXStreamInChunkSend() before calling OCIXStreamInLCRSend() again.
mode (IN)
Specify OCI_DEFAULT.

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Comments
Return codes are:
•

OCI_STILL_EXECUTING means that the current call is still in progress. The connection

associated with the specified service context handle is still tied to this call for
streaming the LCRs to the server. An error is returned if you attempt to use the
same connection to execute any OCI calls that require database round-trip, for
example, OCIStmtExecute(), OCIStmtFetch(), OCILobRead(), and so on. OCILCR* calls
are local calls; thus, they are valid while this call is in progress.
•

OCI_SUCCESS means the current call is completed. You can execute OCIStmt*,
OCILob*, and so on from the same service context.

•

OCI_ERROR means this call encounters some errors. Use OCIErrorGet() to obtain

information about the error.
Related Topics
•

Server Handle Attributes
Lists and describes server handle attributes.

35.3.26 OCIXStreamInLCRCallbackSend()
Sends an LCR stream to the attached inbound server.
Purpose
You must specify a callback to construct each LCR for streaming. If some LCRs
contain chunk data, then a second callback must be provided to create each chunk
data.
Syntax
sword OCIXStreamInLCRCallbackSend (
OCISvcCtx
OCIError
OCICallbackXStreamInLCRCreate
OCICallbackXStreamInChunkCreate
void
ub4

*svchp,
*errhp,
createlcr_cb,
createchunk_cb,
*usrctxp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
createlcr_cb (IN)
Client callback procedure to be invoked to generate an LCR for streaming. Cannot be
NULL.

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createchunk_cb (IN)
Client callback procedure to be invoked to create each chunk. Can be NULL if you do
not need to send any LCR with LOB or LONG or XMLType columns. OCI_ERROR is returned
if this argument is NULL and you attempt to send an LCR with additional chunk data.
usrctxp (IN)
User context to pass to both callback functions.
mode (IN)
Specify OCI_DEFAULT fore now.
Comments
Return code: OCI_ERROR or OCI_SUCCESS.
The createlcr_cb argument must be of type OCICallbackXStreamInLCRCreate:
typedef sb4 (*OCICallbackXStreamInLCRCreate)
void *usrctxp, void **lcrp, ub1 *lcrtyp, oraub8 *flag);

Parameters of OCICallbackXStreamInLCRCreate():
usrctxp (IN/OUT)
Pointer to the user context.
lcrp (OUT)
Pointer to the LCR to be sent.
lcrtyp (OUT)
LCR type (OCI_LCR_XROW or OCI_LCR_XDDL).
flag (OUT)
If OCI_XSTREAM_MORE_ROW_DATA is set, then the current LCR has more chunk data.
The input parameter to the callback is the user context. The output parameters are the
new LCR, its type, and a flag. If the generated LCR contains additional chunk data,
then this flag must have the OCI_XSTREAM_MORE_ROW_DATA (0x01) bit set. The valid return
codes from the OCICallbackXStreamInLCRCreate() callback function are OCI_CONTINUE or
OCI_SUCCESS. This callback function must return OCI_CONTINUE to continue processing the
OCIXStreamInLCRCallbackSend() call. Any return code other than OCI_CONTINUE signals
that the client wants to terminate the OCIXStreamInLCRCallbackSend() call immediately.
In addition, a NULL LCR returned from the OCICallbackXStreamInLCRCreate() callback
function signals that the client wants to terminate the current call.
The createchunk_cb argument must be of type OCICallbackXStreamInChunkCreate:
typedef
void
oratext
ub2
ub2
oraub8
ub2
ub4
ub1
oraub8

sb4 (*OCICallbackXStreamInChunkCreate)
*usrctxp,
**column_name,
*column_name_len,
*column_dty,
*column_flag,
*column_csid,
*chunk_bytes,
**chunk_data,
*flag);

The input parameters of the createchunk_cb() procedure are the user context and the
information about the chunk.

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Parameters of OCICallbackXStreamInChunkCreate():
usrctxp (IN/OUT)
Pointer to the user context.
column_name (OUT)
Column name of the current chunk.
column_name_len (OUT)
Length of the column name.
column_name_dty (OUT)
Chunk data type (SQLT_CHR or SQLT_BIN).
column_flag (OUT)
See Comments in OCIXStreamInChunkSend().
column_csid (OUT)
Column character set ID. Relevant only if the column is an XMLType column (that is,
column_flag has the OCI_LCR_COLUMN_XML_DATA bit set).
chunk_bytes (OUT)
Chunk data length in bytes.
chunk_data (OUT)
Chunk data pointer.
flag (OUT)
If OCI_XSTREAM_MORE_ROW_DATA is set, then the current LCR has more chunk data.
The OCIXStreamInLCRCallbackSend() function invokes the createlcr_cb() procedure to
obtain each LCR to send to the server. If the return flag from the createlcr_cb()
procedure has the OCI_XSTREAM_MORE_ROW_DATA bit set, then it invokes the
createchunk_cb() procedure to obtain each chunk. It repeatedly calls the
createchunk_cb() procedure while the flag returned from this callback has the
OCI_XSTREAM_MORE_ROW_DATA bit set. When this bit is not set, this function cycles back to
invoke the createlcr_cb() procedure to get the next LCR. This cycle is repeated until
the createlcr_cb() procedure returns a NULL LCR or when at the transaction boundary
after an ACK interval has elapsed since the call began.
The valid return codes from the OCICallbackXStreamInChunkCreate() callback function
are OCI_CONTINUE or OCI_SUCCESS. This callback function must return OCI_CONTINUE to
continue processing the OCIXStreamInLCRCallbackSend() call. Any return code other
than OCI_CONTINUE signals that the client wants to terminate the
OCIXStreamInLCRCallbackSend() call immediately.
Because terminating the current call flushes the network and incurs another network
round-trip in the next call, you must avoid returning a NULL LCR immediately when
there is no LCR to send. Doing this can greatly reduce network throughput and affect
performance. During short idle periods, you can add some delays in the callback
procedure instead of returning a NULL LCR immediately to avoid flushing the network
too frequently.
Figure 35-1 shows the execution flow of the OCIXStreamInLCRCallbackSend() function.

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Figure 35-1

Execution Flow of the OCIXStreamInLCRCallbackSend() Function

Client Code
1

Construct LCR

2

LCRCallbackSend

LCRCallbackSend

(createlcr_ cb,
createchunk_cb)
createlcr_cb

LCR, flag

Construct Chunk

3

createchunk_cb

Send to Inbound
Server

*

flag, col_name, chunk_data
LCR is not
NULL

* While OCI_XSTREAM_MORE_ROW_DATA is set
Description of Figure 35-1:
•

At 1, the user invokes the OCIXStreamInLCRCallbackSend() providing two callbacks.
This function initiates an LCR inbound stream to the server.

•

At 2, this function invokes the createlcr_cb() procedure to get an LCR from the
callback to send to the server. If the return LCR is NULL, then this function exits.

•

If the flag from 2 indicates the current LCR has more data (that is, the
OCI_XSTREAM_MORE_ROW_DATA bit is set), then this function proceeds to 3; otherwise, it

loops back to 2 to get the next LCR.
•

At 3, this function invokes createchunk_cb() to get the chunk data to send to the
server. If the flag from this callback has the OCI_XSTREAM_MORE_ROW_DATA bit set, then
it repeats 3; otherwise, it loops back to 2 to get the next LCR from the user. If any
callback function returns any values other than OCI_CONTINUE, then the
OCIXStreamInLCRCallbackSend() call terminates.
Following is a sample client pseudocode snippet for callback mode (error checking
is not included for simplicity):
main
{
/* Attach to inbound server */
OCIXStreamInAttach();
/* Get the server's processed low position to determine
* the position of the first LCR to generate.
*/
OCIXStreamInProcessedLWMGet(&lwm);
while (TRUE)
{
/* Initiate LCR inbound stream */
OCIXStreamInLCRCallbackSend(createlcr_cb, createchunk_cb);

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OCIXStreamInProcessedLWMGet(&lwm);
if (some terminating condition)
break;
}
OCIXStreamInDetach(&lwm);
}

createlcr_cb (IN usrctx, OUT lcr, OUT flag)
{
if (have more LCRs to send)
{
/* construct lcr */
OCILCRHeaderSet(lcr);
OCILCRRowColumnInfoSet(lcr);
if (lcr has LOB | LONG | XMLType columns)
Set OCI_XSTREAM_MORE_ROW_DATA flag;
if (lcr is LOB_ERASE | LOB_TRIM | LOB_WRITE)
OCILCRLobInfoSet(lcr);
}
else if (idle timeout expires)
{
lcr = null;
}
}
createchunk_cb (IN usrctx, OUT chunk, OUT flag)
{
/* set col_name, col_flag, chunk data, and so on */
construct_chunk;
if (last chunk of current column)
{
set col_flag |= OCI_LCR_COLUMN_LAST_CHUNK;
if (last column)
clear OCI_XSTREAM_MORE_ROW_DATA flag;
}
}

Related Topics
•

OCIXStreamInChunkSend()
Sends a chunk to the inbound server.

35.3.27 OCIXStreamInProcessedLWMGet()
Gets the local processed low position that is cached at the client.
Purpose
This function can be called anytime while the client is attached to an XStream inbound
server. Clients, using the callback mode to stream LCRs to the server (see
OCIXStreamInLCRCallbackSend()), can invoke this function while in the callback
procedures.

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Syntax
sword OCIXStreamInProcessedLWMGet ( OCISvcCtx
OCIError
ub1
ub2
ub4

*svchp,
*errhp,
*processed_low_position,
*processed_low_position_len,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
processed_low_position (OUT)
The processed low position maintained at the client.
processed_low_position_len (OUT)
Length of processed_low_position.
mode (IN)
Specify OCI_DEFAULT.
Comments
After attaching to an XStream inbound server, a local copy of the server's processed
low position (see OCIXStreamOutProcessedLWMSet()) is cached at the client. This local
copy is refreshed with the server's low position when each of the following calls returns
OCI_SUCCESS:
•

OCIXStreamInAttach()

•

OCIXStreamInLCRSend()

•

OCIXStreamInLCRCallbackSend()

•

OCIXStreamInFlush()

Return code: OCI_ERROR or OCI_SUCCESS.
You must pass in a preallocated buffer for the position argument. The maximum length
of this buffer is OCI_LCR_MAX_POSITION_LEN. This position is exposed in the
DBA_XSTREAM_INBOUND_PROGRESS view.
The client can use this position to periodically purge the logs used to generate the
LCRs at or below this position.
Related Topics
•

OCIXStreamInLCRCallbackSend()
Sends an LCR stream to the attached inbound server.

•

OCIXStreamOutProcessedLWMSet()
Updates the local copy of the processed low position.

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35.3.28 OCIXStreamInErrorGet()
Returns the first error encountered by the inbound server since attaching to it.
Purpose
Returns the first error encountered by the inbound server since the
OCIXStreamInAttach() call.

Syntax
sword OCIXStreamInErrorGet ( OCISvcCtx
OCIError
sb4
oratext
ub2
ub2
oratext
ub2
ub2

*svchp,
*errhp,
*errcodep,
*msgbuf,
msg_bufsize,
*msg_len,
*txn_id,
txn_id_bufsize,
*txn_id_len );

Parameters
svchp (IN/OUT)
OCI service handle.
errhp (IN/OUT)
Error Handle.
errcodep (OUT)
Error code.
msgbuf (IN/OUT)
Preallocated message buffer.
msg_bufsize (IN)
Message buffer size.
msg_len (OUT)
Length of returned error message.
txn_id (IN/OUT)
Preallocated transaction ID buffer.
txn_id_bufsize (IN)
The transaction ID buffer size.
txn_id_len (OUT)
Length of the returned transaction ID.
Comments
The maximum size for the returned transaction ID is OCI_LCR_MAX_TXID_LEN. If the
allocated buffer for txn_id is too small, then this routine returns ORA-29258. The
maximum size for the returned error msg is OCI_ERROR_MAXMSG_SIZE. If the allocated size
for msgbuf is too small, then the returned message is truncated.

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35.3.29 OCIXStreamInFlush()
Used to flush the network while attaching to an XStream inbound server.
Purpose
It terminates any in-progress OCIXStreamInLCRSend() call associated with the specified
service context.
Syntax
sword OCIXStreamInFlush ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
mode (IN)
OCIXSTREAM_IN_FLUSH_WAIT_FOR_COMPLETE - If this mode is specified, then this function

flushes the network, and then waits for all complete and rollback transactions that
have been sent to the inbound server to complete before returning control to the
client.
Comments
Return code: OCI_ERROR or OCI_SUCCESS.
Each call incurs a database round-trip to get the server's processed low position,
which you can retrieve afterward using OCIXStreamInProcessedLWMGet(). Call this
function only when there is no LCR to send to the server and the client wants to know
the progress of the attached inbound server.
This call returns OCI_ERROR if it is invoked from the callback functions of
OCIXStreamInLCRCallbackSend().

35.3.30 OCIXStreamInChunkSend()
Sends a chunk to the inbound server.
Purpose
This function is valid during the execution of the OCIXStreamInLCRSend() call.
Syntax
sword OCIXStreamInChunkSend ( OCISvcCtx
OCIError
oratext
ub2
ub2

*svchp,
*errhp,
*column_name,
column_name_len,
column_dty,

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oraub8
ub2
ub4
ub1
oraub8
ub4

column_flag,
column_csid,
chunk_bytes,
*chunk_data,
flag,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
column_name (IN)
Name of column associated with the given data. Column name must be canonicalized
and must follow Oracle Database naming convention.
column_name_len (IN)
Length of column name.
column_dty (IN)
LCR chunk data type (must be SQLT_CHR or SQLT_BIN). See Table 35-5.
column_flag (IN)
Column flag. (See Comments for valid column flags.) Must specify
OCI_LCR_COLUMN_LAST_CHUNK for the last chunk of each LOB or LONG or XMLType column.
column_csid (IN)
Column character set ID. This is required only if the column_flag has
OCI_LCR_COLUMN_XML_DATA bit set.
chunk_bytes (IN)
Chunk data length in bytes.
chunk_data (IN)
Pointer to column data chunk. If the column is NCLOB or varying width CLOB, then the
input chunk data must be in AL16UTF16 format. The chunk data must be in the
character set defined in Table 35-5.
flag (IN)
If OCI_XSTREAM_MORE_ROW_DATA (0x01) bit is set, then the current row change contains
more data. You must clear this bit when sending the last chunk of the current LCR.
mode (IN)
Specify OCI_DEFAULT.
Comments
You can call OCIXStreamInChunkSend() to send a chunk of large argument data for a
procedure LCR to the XStream Inbound server.
The following LCR column flags can be combined using bitwise OR operator.
#define OCI_LCR_COLUMN_LOB_DATA
#define OCI_LCR_COLUMN_LONG_DATA
#define OCI_LCR_COLUMN_EMPTY_LOB

/* column contains LOB data */
/* column contains long data */
/* column has an empty LOB */

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#define
#define
#define
#define

OCI_LCR_COLUMN_LAST_CHUNK
OCI_LCR_COLUMN_AL16UTF16
OCI_LCR_COLUMN_NCLOB
OCI_LCR_COLUMN_XML_DATA

/*
/*
/*
/*

last chunk of current column */
column is in AL16UTF16 fmt */
column has NCLOB data */
column contains xml data */

#define OCI_LCR_COLUMN_XML_DIFF

/* column contains xmldiff data */

#define OCI_LCR_COLUMN_ENCRYPTED
#define OCI_LCR_COLUMN_UPDATED

/* column is encrypted */
/* col is updated */

#define OCI_LCR_COLUMN_32K_DATA

/* col contains 32K data */

#define OCI_LCR_COLUMN_OBJECT_DATA /* col contains object data in xml format */

In Streams, LOB, LONG, or XMLType column data is broken up into multiple chunks. For a
row change containing columns of these data types, its associated LCR only contains
data for the other column types. All LOB, LONG or XMLType columns are either
represented in the LCR as NULL or not included in the LCR as defined in Table 35-4.
OCILCRRowColumnInfoSet() is provided to generate a list of scalar columns in an LCR.
For LOB, LONG, and XMLType columns, OCIXStreamInChunkSend() is provided to set the
value of each chunk in a column. For a large column, this function can be invoked
consecutively multiple times with smaller chunks of data. The XStream inbound server
can assemble these chunks and apply the accumulated change to the designated
column.

The LCR of a row change must contain all the scalar columns that can uniquely
identify a row at the apply site. Table 35-4 describes the required column list in each
LCR for each DML operation.
Table 35-4

Required Column List in the First LCR

Command Type of the
First LCR of a Row
Change

Columns Required in the First LCR

INSERT

The NEW column list must contain all non-NULL scalar columns. All
LOB, XMLType, and LONG columns with chunk data must be
included in this NEW column list. Each must have NULL value
and OCI_LCR_COLUMN_EMPTY_LOB flag specified.

UPDATE

The OLD column list must contain the key columns.
The NEW column list must contain all updated scalar columns. All
LOB, XMLType, and LONG columns with chunk data must be
included in this NEW column list. Each must have NULL value
and OCI_LCR_COLUMN_EMPTY_LOB flag specified.

DELETE

The OLD column list must contain the key columns.

LOB_WRITE, LOB_TRIM,
LOB_ERASE

The NEW column list must contain the key columns and the
modified LOB column.

After constructing each LCR, you can call OCIXStreamInLCRSend() to send that LCR.
Afterward, OCIXStreamInChunkSend() can be called repeatedly to send the chunk data
for each LOB or LONG or XMLType column in that LCR. Sending the chunk value for
different columns cannot be interleaved. If a column contains multiple chunks, then
this function must be called consecutively using the same column name before
proceeding to a new column. The ordering of the columns is irrelevant.

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When invoking this function, you must pass OCI_XSTREAM_MORE_ROW_DATA as the flag
argument if there is more data for the current LCR. When sending the last chunk of the
current LCR, then this flag must be cleared to signal the end of the current LCR.
This function is valid only for INSERT, UPDATE, and LOB_WRITE operations. Multiple LOB,
LONG, or XMLType columns can be specified for INSERT and UPDATE, while only one LOB
column is allowed for LOB_WRITE operation.
The following is a sample client pseudocode snippet for non-callback mode (error
checking is not included for simplicity):
main
{
/* Attach to inbound server */
OCIXStreamInAttach();
/* Get the server's processed low position to determine
* the position of the first LCR to generate.
*/
OCIXStreamInProcessedLWMGet(&lwm);
while (TRUE)
{
flag = 0;
/* construct lcr */
OCILCRHeaderSet(lcr);
OCILCRRowColumnInfoSet(lcr);
if (lcr has LOB | LONG | XMLType columns)
set OCI_XSTREAM_MORE_ROW_DATA flag;
status = OCIXStreamInLCRSend(lcr, flag);
if (status == OCI_STILL_EXECUTING &&
(OCI_XSTREAM_MORE_ROW_DATA flag set))
{
for each LOB/LONG/XMLType column in row change
{
for each chunk in column
{
/* set col_name, col_flag, chunk data */
construct chunk;
if (last chunk of current column)
col_flag |= OCI_LCR_COLUMN_LAST_CHUNK;
if (last chunk of last column)
clear OCI_XSTREAM_MORE_ROW_DATA flag;
OCIXStreamInChunkSend(chunk, col_flag, flag);
}
}
}
else if (status == OCI_SUCCESS)
{
/* get lwm when SendLCR call ends successfully. */
OCIXStreamInProcessedLWMGet(&lwm);
}
if (some terminating_condition)
break;

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}
OCIXStreamInDetach();
}

35.3.31 OCIXStreamInCommit()
Commits the given transaction.
Purpose
This function lets the client notify the inbound server about a transaction that has been
executed by the client rather than by the server. So that if the same transaction is
retransmitted during apply restart, it is ignored by the inbound server. A commit LCR
must be supplied for the inbound server to extract the transaction ID and the position
of the commit.
Syntax
sword OCIXStreamInCommit ( OCISvcCtx *svchp,
OCIError *errhp,
void
*lcrp,
ub4
mode );

Parameters
svchp (IN/OUT)
OCI service handle.
errhp (IN/OUT)
Error Handle to which errors should be reported.
lcrp (IN)
Pointer to the LCR to send. Must be a commit LCR.
mode (IN)
Mode flags. Not used currently; used for future extension.
Comments
The position of the input LCR must be higher than
DBA_XSTREAM_INBOUND_PROGRESS.APPLIED_HIGH_POSITION, and the LCR's source database
must match DBA_APPLY_PROGRESS.SOURCE_DATABASE of the attached inbound server.

If there is any pre-commit handler defined, it is executed when this commit LCR is
executed.
Assume a sample use case in which a situation where the inbound server does not
support certain data types, but the client can do the work directly. The client performs
the transaction changes directly to the database and then invokes the
OCIXStreamInCommit() to commit the transaction by way of the inbound server. Note
that the client should not directly commit the transaction itself. Rather, the transaction
changes are committed with this command (OCIXStreamInCommit()) so that the
transaction is atomic. Thus, if the inbound server becomes disabled during the client
transaction, then the entire transaction is correctly rolled back.

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35.3.32 OCIXStreamInSessionSet()
Sets session attributes for XStream In functions.
Purpose
Sets session attributes for XStream In functions.
Syntax
sword OCIXStreamInSessionSet(OCISvcCtx
OCIError
oratext
ub2
void
ub2
ub2
ub4

*svchp,
*errhp,
*attribute_name,
attribute_name_len,
*attribute_value,
attribute_value_len,
attribute_dty,
mode);

Parameters
svchp (IN)
Service handle context.
errhp (IN)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
attribute_name (IN)
An attribute name.
Valid values for attribute_name are:
#define OCIXSTREAM_ATTR_ATTACH_TIMEOUT "ATTACH_TIMEOUT_SECS"
#define OCIXSTREAM_ATTR_MAX_ATTACH_RETRIES "MAX_ATTACH_RETRIES"

attribute_name_len (IN)
An attribute name length.
The maximum value for attribute_name_len is OCIXSTREAM_SESSION_SET_MAX_PARAM_LEN:
#define OCIXSTREAM_SESSION_SET_MAX_PARAM_LEN

128

attribute_value (IN)
The attribute value.
attribute_value_len (IN)
The attribute value length.
The maximum value for attribute_value_len is 128.
attribute_dty (IN)
Pointer to an array of attribute data types. The only valid value for attribute_dty is
DTYUB2. An error is returned if you try a data type other than DTYUB2 for
ATTACH_TIMEOUT_SECS and MAX_ATTACH_RETRIES.
mode (IN)
Specify OCI_DEFAULT.

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Comments
You must invoke OCIXStreamInSessionSet() before calling OCIXStreamInAttach().
Returns
OCI_SUCCESS if successful, otherwise OCI_ERROR.

35.3.33 OCIXStreamOutAttach()
Attaches to an XStream outbound server.
Purpose
The client application must connect to the database using a dedicated connection.
Syntax
sword OCIXStreamOutAttach ( OCISvcCtx
OCIError
oratext
ub2
ub1
ub2
ub4

*svchp,
*errhp,
*server_name,
server_name_len,
*last_position,
last_position_len,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
server_name (IN)
XStream outbound server name.
server_name_len (IN)
Length of XStream outbound server name.
last_position (IN)
Position to the last received LCR. Can be NULL.
last_position_len (IN)
Length of last_position.
mode (IN)
OCIXSTREAM_OUT_ATTACH_APP_FREE_LCR - If this mode is specified, then the application is

in charge of freeing the LCRs from the outbound server.
OCIXSTREAM_OUT_ATTACH_APP_CONTAINER - If this mode is specified, then the application is

capturing application container statements (ALTER PLUGGABLE DATABASE
APPLICATIONS LCRs). The XStream application should set this mode option if it is
intending to replicate ALTER PLUGGABLE DATABASE APPLICATIONS LCRs to
other application containers.

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OCIXSTREAM_OUT_ATTACH_EXTENDED_TXID - If this mode is specified, then the application is

making a request for extended transaction ID format. The typical transaction ID format
is xidusn.xidslt.xidsqn. The extended transaction ID format is
pdbuid.xidusn.xidslt.xidsqn. Use this mode if the XStream Out server is configured
to capture changes from multiple containers and the source database has local undo
mode enabled.
Comments
The OCIEnv environment handle must be created with OCI_OBJECT mode, and the service
context must be in a connected state to issue this function. This function does not
support nonblocking mode. It returns either the OCI_SUCCESS or OCI_ERROR status code.
The name of the outbound server must be provided because multiple outbound
servers can be configured in one Oracle Database instance. This function returns
OCI_ERROR if it encounters any error while attaching to the outbound server. Only one
client can attach to an XStream outbound server at any time. An error is returned if
multiple clients attempt to attach to the same outbound server or if the same client
attempts to attach to multiple outbound servers using the same service handle.
The last_position parameter is used to establish the starting point of the stream. This
call returns OCI_ERROR if the specified position is non-NULL and less than the server's
processed low position (see OCIXStreamOutProcessedLWMSet()); otherwise, LCRs with
positions greater than the specified last_position are sent to the user.
If the last_position is NULL, then the stream starts from the processed low position
maintained in the server.
Related Topics
•

OCIXStreamOutProcessedLWMSet()
Updates the local copy of the processed low position.

35.3.34 OCIXStreamOutDetach()
Detaches from the outbound server.
Purpose
Detaches from the outbound server.
Syntax
sword OCIXStreamOutDetach ( OCISvcCtx
OCIError
ub4

*svchp,
*errhp,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information in case
of an error.

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mode (IN)
Specify OCI_DEFAULT.
Comments
This function sends the current local processed low position to the server before
detaching from the outbound server. The outbound server automatically restarts after
this call. This function returns OCI_ERROR if it is invoked while a OCIXStreamOutReceive()
call is in progress.

35.3.35 OCIXStreamOutLCRReceive()
Receives an LCR, including a procedure LCR, from an outbound stream.
Purpose
If an LCR is available, then this function immediately returns that LCR. The duration of
each LCR is limited to the interval between two successive OCIXStreamOutLCRReceive()
calls. When there is no LCR available in the stream, this call returns a NULL LCR after
an idle timeout.
Syntax
sword OCIXStreamOutLCRReceive ( OCISvcCtx
OCIError
void
ub1
oraub8
ub1
ub2
ub4

*svchp,
*errhp,
**lcrp,
*lcrtype,
*flag,
*fetch_low_position,
*fetch_low_position_len,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
lcrp (OUT)
Pointer to the LCR received from the stream; can include a procedure LCR. If there is
an available LCR, then this LCR is returned with status code OCI_STILL_EXECUTING.
When the call ends, a NULL LCR is returned with status code OCI_SUCCESS.
lcrtype (OUT)
This value is valid only when lcrp is not NULL.
flag (OUT)
Return flag. If bit OCI_XSTREAM_MORE_ROW_DATA (0x01) is set, then this LCR has more
data. You must use OCIXStreamOutReceiveChunk() function to get the remaining data.

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fetch_low_position (OUT)
XStream outbound server's fetch low position. This value is returned only when the
return code is OCI_SUCCESS. Optional. If non-NULL, then you must preallocate
OCI_LCR_MAX_POSITION_LEN bytes for the return value.
fetch_low_position_len (OUT)
Length of fetch_low_position.
mode (IN)
Specify OCI_DEFAULT.
Comments
To avoid a network round-trip for every OCIXStreamOutLCRReceive() call, the connection
is tied to this call and allows the server to fill up the network buffer with LCRs so
subsequent calls can quickly receive the LCRs from the network. The server ends
each call at the transaction boundary after an ACK interval elapses since the call
began. When there is no LCR in the stream, the server ends the call after the idle
timeout elapses.
Return codes:
•

OCI_STILL_EXECUTING means that the current call is still in progress. The connection

associated with the specified service context handle is still tied to this call for
streaming the LCRs from the server. An error is returned if you attempt to use the
same connection to execute any OCI calls that require database round-trip, for
example, OCIStmtExecute(), OCIStmtFetch(), OCILobRead(), and so on. OCILCR* calls
do not require round-trips; thus, they are valid while the call is in progress.
•

OCI_SUCCESS means that the current call is completed. You are free to execute
OCIStmt*, OCILob*, and so on from the same service context.

•

OCI_ERROR means the current call encounters some errors. Use OCIErrorGet() to

obtain information about the error.
This call always returns a NULL LCR when the return code is OCI_SUCCESS. In addition, it
returns the fetch low position to denote that the outbound server has received all
transactions with commit position lower than or equal to this value.

See Also:
•

Server Handle Attributes

•

OCIXStreamOutChunkReceive() for non-callback pseudocode in the
Comments section

35.3.36 OCIXStreamOutLCRCallbackReceive()
Used to get the LCR stream from the outbound server using callbacks.
Purpose
You must supply a callback procedure to be invoked for each LCR received. If some
LCRs in the stream may contain LOB or LONG or XMLType columns, then a second
callback must be supplied to process each chunk (see OCIXStreamOutChunkReceive()).

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Syntax
sword OCIXStreamOutLCRCallbackReceive (
OCISvcCtx
OCIError
OCICallbackXStreamOutLCRProcess
OCICallbackXStreamOutChunkProcess
void
ub1
ub2
ub4

*svchp,
*errhp,
processlcr_cb,
processchunk_cb,
*usrctxp,
*fetch_low_position,
*fetch_low_position_len,
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
processlcr_cb (IN)
Callback function to process each LCR received by the client. Cannot be NULL.
processchunk_cb (IN)
Callback function to process each chunk in the received LCR. Can be NULL if you do
not expect to receive any LCRs with additional chunk data.
usrctxp (IN)
User context to pass to both callback procedures.
fetch_low_position (OUT)
XStream outbound server's fetch low position (see OCIXStreamOutLCRReceive()).
Optional.
fetch_low_position_len (OUT)
Length of fetch_low_position.
mode (IN)
Specify OCI_DEFAULT.
Comments
Return code: OCI_SUCCESS or OCI_ERROR.
The processlcr_cb argument must be of type OCICallbackXStreamOutLCRProcess:
typedef sb4 (*OCICallbackXStreamOutLCRProcess)
(void *usrctxp, void *lcrp, ub1 lcrtyp, oraub8 flag);

Parameters of OCICallbackXStreamOutLCRProcess():
usrctxp (IN/OUT)
Pointer to the user context.
lcrp (IN)
Pointer to the LCR just received.

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lcrtyp (IN)
LCR type (OCI_LCR_XROW or OCI_LCR_XDDL).
flag (IN)
If OCI_XSTREAM_MORE_ROW_DATA is set, then the current LCR has more chunk data.
The input parameters of the processlcr_cb() procedure are the user context, the LCR
just received, its type, and a flag to indicate whether the LCR contains more data. If
there is an LCR available, then this callback is invoked immediately. If there is no LCR
in the stream, after an idle timeout, then this call ends with OCI_SUCCESS return code.
You can invoke the callback OCICallbackXStreamOutLCRProcess to process procedure
LCRs as well.
The valid return codes from the OCICallbackXStreamOutLCRProcess() callback function
are OCI_CONTINUE or OCI_SUCCESS. This callback function must return OCI_CONTINUE to
continue processing the OCIXStreamOutLCRCallbackReceive() call. Any return code other
than OCI_CONTINUE signals that the client wants to terminate
OCIXStreamOutLCRCallbackReceive() immediately.

See Also:
Server Handle Attributes

The processchunk_cb argument must be of type OCICallbackXStreamOutChunkProcess:
typedef sb4 (*OCICallbackXStreamOutChunkProcess)
(void
*usrctxp,
oratext
*column_name,
ub2
column_name_len,
ub2
column_dty,
oraub8
column_flag,
ub2
column_csid,
ub4
chunk_bytes,
ub1
*chunk_data,
oraub8
flag );

Parameters of OCICallbackXStreamOutChunkProcess():
usrctxp (IN/OUT)
Pointer to the user context.
column_name (IN)
Column name of the current chunk.
column_name_len (IN)
Length of the column name.
column_name_dty (IN)
Chunk data type (SQLT_CHR or SQLT_BIN).
column_flag (IN)
See Comments in OCIXStreamInChunkSend().

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column_csid (IN)
Column character set ID. Relevant only if the column is an XMLType column (that is,
column_flag has the OCI_LCR_COLUMN_XML_DATA bit set).
chunk_bytes (IN)
Chunk data length in bytes.
chunk_data (IN)
Chunk data pointer.
flag (IN)
If OCI_XSTREAM_MORE_ROW_DATA is set, then the current LCR has more chunk data.
The input parameters of the processchunk_cb() procedure are the user context, the
information about the chunk, and a flag. When the flag argument has the
OCI_XSTREAM_MORE_ROW_DATA (0x01) bit set, then there is more data for the current LCR.
The valid return codes from the OCICallbackXStreamOutChunkProcess() callback function
are OCI_CONTINUE or OCI_SUCCESS. This callback function must return OCI_CONTINUE to
continue processing the OCIXStreamOutLCRCallbackReceive() call. Any return code other
than OCI_CONTINUE signals that the client wants to terminate
OCIXStreamOutLCRCallbackReceive() immediately.
OCI calls are provided to access each field in the LCR. If the LCR contains only scalar
column(s), then the duration of that LCR is limited only to the processlcr_cb()
procedure. If the LCR contains some chunk data, then the duration of the LCR is
extended until all the chunks have been processed. If you want to access the LCR
data at a later time, then a copy of the LCR must be made before it is freed.
As for OCIXStreamOutLCRReceive(), the server ends each call at the transaction
boundary after each ACK interval since the call began, or after each idle timeout. The
default ACK interval is 30 seconds, and the default idle timeout is one second. See
"Server Handle Attributes" to tune these values. This function also returns the fetch
low position when the call ends.
Figure 35-2 shows the execution flow of the OCIXStreamOutLCRCallbackReceive()
function.
Figure 35-2

Execution Flow of the OCIXStreamOutLCRCallbackReceive() Function

Client Code
1

Process LCR

2

LCRCallbackReceive

LCRCallbackReceive

(processlcr_ cb,
processchunk_cb)
processlcr_cb
(LCR, flag)
Receive From
Outbound Server

Process Chunk

3

processchunk_cb

*

(col_name, chunk)

while more
LCRs from
stream

* While OCI_XSTREAM_MORE_ROW_DATA is set.

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Description of Figure 35-2:
•

At 1, the client invokes OCIXStreamOutLCRCallbackReceive() providing two callbacks.
This function initiates an LCR outbound stream from the server.

•

At 2, this function receives an LCR from the stream and invokes processlcr_cb()
procedure with the LCR just received. It passes OCI_XSTREAM_MORE_ROW_DATA flag to
processlcr_cb() if the current LCR has additional data.

•

If the current LCR has no additional chunk, then this function repeats 2 for the next
LCR in the stream.

•

At 3, if the current LCR contains additional chunk data, then this function invokes
processchunk_cb() for each chunk received with the OCI_XSTREAM_MORE_ROW_DATA flag.

This flag is cleared when the callback is invoked on the last chunk of the current
LCR.
•

If there is more LCR in the stream, then it loops back to 2. This process continues
until the end of the current call, or when there is no LCR in the stream for one
second, or if a callback function returns any value other than OCI_CONTINUE.

Here is sample pseudocode for callback mode:
main
{
/* Attach to outbound server specifying last position */
OCIXStreamOutAttach(last_pos);
/* Update the local processed low position */
OCIXStreamOutProcessedLWMSet(lwm);
while (TRUE)
{
OCIXStreamOutLCRCallbackReceive(processlcr_cb,
processchunk_cb, fwm);
/* Use fetch low position(fwm)
* to update processed lwm if applied.
*/
/* Update the local lwm so it is sent to
* server during next call.
*/
OCIXStreamOutProcessedLWMSet(lwm);
if (some terminating_condition)
break;
}
OCIXStreamOutDetach();
}
processlcr_cb (IN lcr, IN flag)
{
/* Process the LCR just received */
OCILCRHeaderGet(lcr);
OCILCRRowColumnInfoGet(lcr);
if (lcr is LOB_WRITE | LOB_TRIM | LOB_ERASE)
OCILCRLobInfoGet(lcr);
if (OCI_XSTREAM_MORE_ROW_DATA flag set)
prepare_for_chunk_data;
else

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process_end_of_row;
}
processchunk_cb (IN chunk, IN flag)
{
process_chunk;
if (OCI_XSTREAM_MORE_ROW_DATA flag not set)
process_end_of_row;
}

Related Topics
•

OCIXStreamOutChunkReceive()
Retrieves data of each LOB or LONG or XMLType column one chunk at a time.

•

OCIXStreamOutLCRReceive()
Receives an LCR, including a procedure LCR, from an outbound stream.

•

OCIXStreamInChunkSend()
Sends a chunk to the inbound server.

35.3.37 OCIXStreamOutProcessedLWMSet()
Updates the local copy of the processed low position.
Purpose
This function can be called anytime between OCIXStreamOutAttach() and
OCIXStreamOutDetach() calls. Clients using the callback mechanism to stream LCRs
from the server (see OCIXStreamOutLCRCallbackReceive()), can invoke this function while
in the callback procedures.
Syntax
sword OCIXStreamOutProcessedLWMSet ( OCISvcCtx *svchp,
OCIError *errhp,
ub1
*processed_low_position,
ub2
processed_low_position_len,
ub4
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
processed_low_position (IN)
The processed low position maintained at the client.
processed_low_position_len (IN)
Length of processed_low_position.
mode (IN)
Specify OCI_DEFAULT.

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Comments
The processed low position denotes that all LCRs at or below it have been processed.
After successfully attaching to an XStream outbound server, a local copy of the
processed low position is maintained at the client. Periodically, this position is sent to
the server so that archived redo log files containing already processed transactions
can be purged.
Return code: OCI_SUCCESS or OCI_ERROR.
Clients using XStreamOut functions must keep track of the processed low position
based on what they have processed and call this function whenever their processed
low position has changed. This is done so that a more current value is sent to the
server during the next update, which occurs at the beginning of the
OCIXStreamOutLCRCallbackReceive() and OCIXStreamDetach() calls. For an
OCIXStreamOutLCRReceive() call, the processed low position is sent to the server when it
initiates a request to start the outbound stream. It is not sent while the stream is in
progress.
You can query the DBA_XSTREAM_OUTBOUND_PROGRESS view to confirm that the processed
low position has been saved in the server.
Related Topics
•

OCIXStreamOutLCRCallbackReceive()
Used to get the LCR stream from the outbound server using callbacks.

35.3.38 OCIXStreamOutChunkReceive()
Retrieves data of each LOB or LONG or XMLType column one chunk at a time.
Purpose
Allows the client to retrieve the data of each LOB or LONG or XMLType column one chunk
at a time.
Syntax
sword OCIXStreamOutChunkReceive ( OCISvcCtx *svchp,
OCIError
*errhp,
oratext
**column_name,
ub2
*column_name_len,
ub2
*column_dty,
oraub8
*column_flag,
ub2
*column_csid,
ub4
*chunk_bytes,
ub1
**chunk_data,
oraub8
*flag,
ub4
mode );

Parameters
svchp (IN)
Service handle context.

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errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
column_name (OUT)
Name of the column that has data.
column_name_len (OUT)
Length of the column name.
column_dty (OUT)
Column chunk data type (either SQLT_CHR or SQLT_BIN).
column_flag (OUT)
Column flag. See Comments for valid flags.
column_csid (OUT)
Column character set ID. This is returned only for XMLType column, that is, column_flag
has OCI_LCR_COLUMN_XML_DATA bit set.
chunk_bytes (OUT)
Number of bytes in the returned chunk.
chunk_data (OUT)
Pointer to the chunk data in the LCR. The client must not deallocate this buffer since
the LCR and its contents are maintained by this function.
flag (OUT)
If OCI_XSTREAM_MORE_ROW_DATA (0x01) is set, then the current LCR has more chunks
coming.
mode (IN)
Specify OCI_DEFAULT.
Comments
In Streams, LOB, LONG, or XMLType column data is broken up into multiple LCRs based
on how they are stored in the online redo log files. Thus, for a row change containing
these columns multiple LCRs may be constructed. The first LCR of a row change
contains the column data for all the scalar columns. All LOB or LONG or XMLType
columns in the first LCR are set to NULL because their data are sent in subsequent
LCRs for that row change. These column data are stored in the LCR as either RAW
(SQLT_BIN) or VARCHAR2 (SQLT_CHR) chunks as shown in Table 35-5.
Table 35-5

Storage of LOB or LONG Data in the LCR

Source Column Data Type

Streams LCR Data Type

Streams LCR Character Set

BLOB

RAW

N/A

Fixed-width CLOB

VARCHAR2

Client Character Set

Varying-width CLOB

RAW

AL16UTF16

NCLOB

RAW

AL16UTF16

XMLType

RAW

Column csid obtained from the
chunk

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In Streams, LOB, LONG, or XMLType column data is broken up into multiple chunks based
on how they are stored in the online redo log files. For a row change containing
columns of these data types, its associated LCR only contains data for the other scalar
columns. All LOB, LONG, or XMLType columns are either represented in the LCR as NULL
or not included in the LCR. The actual data for these columns are sent following each
LCR as RAW (SQLT_BIN) or VARCHAR2 (SQLT_CHR) chunks as shown in Table 35-5.
The following LCR column flags can be combined using the bitwise OR operator.
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_COLUMN_LOB_DATA
OCI_LCR_COLUMN_LONG_DATA
OCI_LCR_COLUMN_EMPTY_LOB
OCI_LCR_COLUMN_LAST_CHUNK
OCI_LCR_COLUMN_AL16UTF16
OCI_LCR_COLUMN_NCLOB
OCI_LCR_COLUMN_XML_DATA

/*
/*
/*
/*
/*
/*
/*

column contains LOB data */
column contains long data */
column has an empty LOB */
last chunk of current column */
column is in AL16UTF16 fmt */
column has NCLOB data */
column contains xml data */

#define OCI_LCR_COLUMN_XML_DIFF

/* column contains xmldiff data */

#define OCI_LCR_COLUMN_ENCRYPTED
#define OCI_LCR_COLUMN_UPDATED

/* column is encrypted */
/* col is updated */

#define OCI_LCR_COLUMN_32K_DATA

/* col contains 32K data */

#define OCI_LCR_COLUMN_OBJECT_DATA /* col contains object data in xml format */

Return code: OCI_ERROR or OCI_SUCCESS.
This call returns a NULL column name and NULL chunk data if it is invoked when the
current LCR does not contain the LOB, LONG, or XMLType columns. This function is valid
only when an OCIXStreamOutLCRReceive() call is in progress. An error is returned if it is
called during other times.
If the return flag from OCIXStreamOutLCRReceive() has OCI_XSTREAM_MORE_ROW_DATA bit set,
then you must iteratively call OCIXStreamOutChunkReceive() to retrieve all the chunks
belonging to that row change before getting the next row change (that is, before
making the next OCIXStreamOutLCRReceive() call); otherwise, an error is returned.
Here is sample pseudocode for non-callback mode:
main
{
/* Attach to outbound server specifying last position */
OCIXStreamOutAttach(last_pos);
/* Update the local processed low position */
OCIXStreamOutProcessedLWMSet(lwm);
while (TRUE)
{
status = OCIXStreamOutLCRReceive(lcr, flag, fwm);
if (status == OCI_STILL_EXECUTING)
{
/* Process LCR just received */
OCILCRHeaderGet(lcr);
OCILCRRowColumnInfoGet(lcr);
while (OCI_XSTREAM_MORE_ROW_DATA flag set)
{
OCIXStreamReceiveChunk(chunk, flag, );

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process_chunk;
}
process_end_of_row;
}
else if (status == OCI_SUCCESS)
{
/* Use fetch low position(fwm)
* to update processed lwm if applied.
*/
/* Update the local lwm so it is sent to
* server during next call.
*/
OCIXStreamOutProcessedLWMSet(lwm);
if (some terminating_condition)
break;
}
}
OCIXStreamOutDetach();
}

35.3.39 OCIXStreamOutGetNextChunk()
While in the ProcessLCRStream() callback function, retrieves the next chunk in the
current LCR until all chunks are retrieved.
Purpose
While in the ProcessLCRStream() callback function, the client must repeatedly call
OCIXStreamOutGetNextChunk() to retrieve all the chunks in the current LCR (that is, until
either OCI_ERROR or OCI_SUCCESS is returned). If this is not done, an error will be raised
when the callback function ends.
Syntax
sword OCIXStreamOutGetNextChunk ( OCISvcCtx *svchp,
OCIError
*errhp,
oratext
**column_name,
ub2
*column_name_len,
ub2
*column_dty,
oraub8
*column_flag,
ub4
*rtn_bytes,
ub1
**bufp,
ub4
*op_offset,
ub4
*op_size,
ub4
mode );

Parameters
svchp (IN)
Service handle context.
errhp (IN/OUT)
An error handle you can pass to OCIErrorGet() for diagnostic information in the event
of an error.

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column_name (OUT)
Name of LOB column which the data belongs to.
column_name_len (OUT)
Length of column name.
column_dty (OUT)
Column data type (either SQLT_CHR or SQLT_BIN).
column_flag (OUT)
Column flag. Valid values are listed in Comments.
rtn_bytes (OUT)
Number of bytes in returned buffer.
bufp (OUT)
Pointer to the LOB chunk data in the LCR. The client should not de-allocate this buffer
since the LCR and its contents are maintained by the function.
op_offset (OUT)
LOB operation offset. Optional. Data is not returned if the argument is NULL. Relevant
only for LOB_WRITE and LOB_TRIM operation; otherwise, a zero is returned.
op_size (OUT)
LOB operation size. Optional. Data not returned if the argument is NULL. Relevant only
for LOB_TRIM and LOB_ERASE operation; otherwise, a zero is returned.
mode (IN)
Specify OCI_DEFAULT for now.
Comments
The OCIEnv environment handle must be created with OCI_OBJECT mode, and the service
context must be in connected state to issue this function.
In streams, LOB or LONG column data is broken up into multiple LCRs based on how
they are stored in the redo logs. Thus, for a row change containing Re LONG columns,
multiple LCRs can be constructed. The first LCR of a row change contains the column
data for all the scalar columns. All LOB or LONG columns in the first LCR are set to NULL
since their data are sent in subsequent LCRs for that row change. LONG column data is
implicitly converted to LOB before the data is sent to the client. LOB or LONG data is
stored in the LCR as RAW (SQLT_BIN) or VARCHAR2 (SQLT_CHR) as shown in Table 35-5:
The OCIXStreamOutProcessLCRStream() function allows the client to retrieve the data of
each LOB or LONG column one chunk at a time. All the chunks belonging to one
column are returned in a contiguous order. Chunk data from one column is returned
entirely before switching to the next column. There is no fixed ordering on how the
columns are returned. The client should not rely on the ordering of LOB columns but
rely on the returned column names.
Invoking OCIXStreamOutGetNextChunk() when the current LCR contains only scalar
columns results in a NULL column name, and no data is returned.
The returned column flag provides more information on each chunk data. For example,
the flag OCI_LCR_COLUMN_LAST_CHUNK is always returned on the last chunk of each
column:

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The following flags can specify a column property. Multiples of these flags can be
combined using the bitwise OR operator.
#define
#define
#define
#define
#define
#define
#define
#define
#define

OCI_LCR_COLUMN_LOB_DATA /* column contains lob data */
OCI_LCR_COLUMN_LONG_DATA /* column contains long data */
OCI_LCR_COLUMN_EMPTY_LOB /* column has an empty lob */
OCI_LCR_COLUMN_LAST_CHUNK /* last chunk of column */
OCI_LCR_COLUMN_AL16UTF16 /* column is in AL16UTF16 fmt */
OCI_LCR_COLUMN_NCLOB /* column has NCLOB data */
OCI_LCR_COLUMN_XML_DATA /* column contains xml data */
OCI_LCR_COLUMN_XML_DIFF /* column contains xmldiff */
OCI_LCR_COLUMN_ENCRYPTED /* column is encrypted */

During an OCIXStreamOutProcessLCRStream() call, the client provides a callback function
that will be invoked each time an LCR is retrieved. For an LCR containing LOB or LONG
columns, the first LCR of a row change is passed to this callback function. From within
this callback function, the client can repeatedly call OCIXStreamOutGetNextChunk() to
retrieve all the chunks for each LOB or LONG column. When this function returns
OCI_SUCCESS, it means the client has consumed all the data for the current row change.
While in the ProcessLCRStream callback function the client must repeatedly call
OCIXStreamOutGetNextChunk() to retrieve all the chunks in the current LCR (that is, until
either OCI_ERROR or OCI_SUCCESS is returned). If this is not done, an error is raised when
the callback function ends.
This function is valid only during the duration that the ProcessLCRStream callback
function is invoked. An error is raised if it is called during other times.
This function returns the following values:
•

OCI_SUCCESS means that all the data for the current LCR has been retrieved. You

can check the returned column and buffer information to access the returned
column data.
•

OCI_NEED_DATA means there is more data in the stream for the current LCR. You

can check the returned column and buffer information to access the returned
column data.
•

OCI_ERROR means there is an error. You can use OCIErrorGet() to get the error

code.
Following is a sample client code snippet (error checking is not included for simplicity):
main()
{
...
OCIServerAttach(...); /* Connect to Oracle db */
/* Attach to the outbound server named ‘TT1' */
OCIXStreamOutAttach(...,“TT1", 3, hwm, hwm_len, (OCIDate *)0, OCI_DEFAULT);
/*-------------------------------------------------------Initialize the LWM by querying the client's system tables
or set to zero and let the outbound server determines the LWM.
--------------------------------------------------------*/
Init_lwm(&lwm);
/*--------------------------------------------------------ProcessLCR_CB is a callback function to process each LCR (see below).
usrctxp is the user context to be passed to the callback function.
--------------------------------------------------------*/
while (OCIXStreamOutProcessLCRStream(..., lwm, lwm_len,(OCIDate *)0,
ProcessLCR_CB, usrctxp, 0, OCI_DEFAULT) == OCI_SUCCESS)
{

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/* Client maintains LWM. */
Maintain_lwm(&lwm);
...
}
/* detach from the outbound server */
OCIXStreamOutDetach(..., lwm, lwm_len, (OCIDate *)0, OCI_DEFAULT);
}
/* Sample callback routine to OCIXStreamOutProcessLCRStream() */
sb4 ProcessLCR_CB (void *ctxp, void *lcrp, ub1 lcrtyp)
{
/* Get header information for current LCR */
status = OCILCRGetHeader(lcrp,...);
if (status != OCI_SUCCESS)
handle_error();
if (lcrtype == OCI_LCR_XROW)
{
if (OCILcrRowGetColumnInfo(lcrp, ...) != OCI_SUCCESS)
handle_error();
process_scalar_columns(...);
do
{
status = OCIXStreamOutGetNextChunk(..., &colname, &colnamelen,
&coldty, &flag, &rtn_bytes,
bufp, ...);
if (status == OCI_ERROR)
handle_error();
process_lob_chunk(...);
} while (status == OCI_NEED_DATA);
if (status == OCI_ERROR)
handle_error();
}
return OCI_CONTINUE;
}

35.3.40 OCIXStreamOutSessionSet()
Sets session attributes for XStream Out functions.
Purpose
Sets session attributes for XStream Out functions.
Syntax
sword OCIXStreamOutSessionSet(OCISvcCtx
OCIError
oratext
ub2
void
ub2
ub2
ub4

*svchp,
*errhp,
*attribute_name,
attribute_name_len,
*attribute_value,
attribute_value_len,
attribute_dty,
mode);

Parameters
svchp (IN)
Service handle context.

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errhp (IN)
An error handle you can pass to OCIErrorGet() for diagnostic information in case of an
error.
attribute_name (IN)
An attribute name.
Valid values for attribute_name are:
#define OCIXSTREAM_ATTR_ATTACH_TIMEOUT "ATTACH_TIMEOUT_SECS"
#define OCIXSTREAM_ATTR_MAX_ATTACH_RETRIES "MAX_ATTACH_RETRIES"

attribute_name_len (IN)
An attribute name length.
The maximum value for attribute_name_len is OCIXSTREAM_SESSION_SET_MAX_PARAM_LEN:
#define OCIXSTREAM_SESSION_SET_MAX_PARAM_LEN

128

attribute_value (IN)
The attribute value.
attribute_value_len (IN)
The attribute value length.
The maximum value for attribute_value_len is 128.
attribute_dty (IN)
Pointer to an array of attribute data types. The only valid value for attribute_dty is
DTYUB2. An error is returned if you try a data type other than DTYUB2 for
ATTACH_TIMEOUT_SECS and MAX_ATTACH_RETRIES.
mode (IN)
Specify OCI_DEFAULT.
Comments
You must invoke OCIXStreamOutSessionSet() before calling OCIXStreamOutAttach().
Returns
OCI_SUCCESS if successful, otherwise OCI_ERROR.

35-72

36
OCI SODA Functions
This chapter describes the OCI SODA functions.
This chapter contains these topics:
•

Introduction to OCI SODA Functions

•

OCI SODA Functions

36.1 Introduction to OCI SODA Functions
The Simple Oracle Document (SODA) for C API is part of Oracle Call Interface (OCI).
SODA for C allows OCI programmers to store and query Javascript Object Notation
(JSON) data and access JSON functionality in the database with abstractions:
databases, collections, and documents. A database contains collections and
collections contain documents. The API provides create, read, update, and delete
(CRUD) operations on the document collections.
Conventions for OCI Functions
See Conventions for OCI Functions for the conventions used in describing each
function. The entries for each function may also contain the following information:
Returns.

See Also:
•

https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/
index.html

•

Oracle Database JSON Developer’s Guide

36.2 OCI SODA Functions
The following table lists the OCI SODA functions that are described in this chapter.
Table 36-1

OCI SODA Functions

Function

Purpose

OCISodaCollCreate()

Creates a new document collection with
default metadata settings.

OCISodaCollCreateWithMetadata()

Creates a new document collection with
metadata.

OCISodaCollOpen()

Opens the collection.

36-1

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OCI SODA Functions

Table 36-1

(Cont.) OCI SODA Functions

Function

Purpose

OCISodaCollList()

Lists the collections in the schema associated
with the supplied service context handle
parameter.

OCISodaCollGetNext()

Gets the next collection from the collection
cursor.

OCISodaCollDrop()

Drops a collection from the database.

OCISodaDocCreate()

Creates a document.

OCISodaDocCreateWithKey()

Creates a document with document key and
content.

OCISodaDocCreateWithKeyAndMType()

Creates a document with document key,
content, and media type.

OCISodaFindOneWithKey()

Finds a single document in a collection given a
key.

OCISodaInsert()

Inserts a document into a collection.

OCISodaInsertAndGet()

Inserts a document into a collection and
returns a result document containing
document components, such as key, version,
and timestamp, except for content.

OCISodaInsertAndGetWithCtnt()

Inserts a document into a collection using just
the content and returns a result document
handle with the document components, except
for content.

OCISodaInsertWithCtnt()

Inserts a document into a collection using just
the content.

OCISodaRemoveOneWithKey()

Removes a document from a collection given
a key.

OCISodaReplOneAndGetWithKey()

Replaces a document in a collection given a
key and returns the handle to the result
document containing document components,
including the updated ones, such as lastmodified timestamp, version, and media type.

OCISodaReplOneWithKey()

Replaces a document in a collection given a
key.

36.2.1 OCISodaCollCreate()
Creates a new document collection with default metadata settings.
Purpose
To create a new document collection with default metadata settings.
Syntax
sword OCISodaCollCreate(OCISvcCtx
*svchp,
const OraText *collname,
ub4
collnamelen,
OCISodaColl
**collection,

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OCIError
ub4

*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collname (IN)

The name of the collection.

collnamelen (IN)

The length of the collection name.

collection (OUT)

Allocates the collection handle representing
the document collection that was created. Call
OCIHandleFree() to free the collection handle
when it is no longer required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if the collection is successfully created.
OCI_ERROR, if the collection is not created. The OCIError parameter has the necessary
error information.

Usage Notes
•

If the collection with the specified name already exists, then this function acts as
OCISodaCollOpen() and opens the existing collection.

Examples
Example 36-1

Creating a Collection

See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.2 OCISodaCollCreateWithMetadata()
Creates a new document collection with metadata.
Purpose
To create a new document collection with metadata.
Syntax
sword OCISodaCollCreateWithMetadata(OCISvcCtx
const OraText
ub4
OraText
ub4
OCISodaColl

*svchp,
*collname,
collnamelen,
*metadata,
metadatalen,
**collection,

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OCIError
ub4

*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collname (IN)

The name of the collection.

collnamelen (IN)

The length of the collection name.

metadata (IN)

The JSON string that contains the collection
metadata information. If metadata is NULL, it
uses the default metadata settings to create
the collection.

metadatalen (IN)

The length of the metadata JSON string.

collection (OUT)

Allocates the collection handle representing
the document collection that was created. Call
OCIHandleFree() to free the collection handle
when it is no longer required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if the collection is successfully created.
OCI_ERROR, if the collection is not created. The OCIError parameter has the necessary
error information.

Usage Notes
•

If the collection with the specified name already exists and that collection has
metadata equivalent to the supplied metadata, then this function acts as
OCISodaCollOpen() and opens the existing collection. If the collection contains
metadata that does not match with the specified collection name, then an error is
returned.

Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.3 OCISodaCollOpen()
Opens the collection.
Purpose
To open the collection.

36-4

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Syntax
sword OCISodaCollOpen(OCISvcCtx
const OraText
ub4
OCISodaColl
OCIError
ub4

*svchp,
*collname,
collnamelen,
**coll,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collname (IN)

The name assigned to the collection.

collnamelen (IN)

The length of the collection name.

coll (OUT)

Allocates the collection handle and returns it
with the specified collection name. The
function returns OCI_SUCCESS if there are no
errors while trying to open the collection. If the
collection with the supplied name is not
present, that is not considered an error and
returns OCI_SUCCESS, but the collection-handle
pointer returns as NULL. So a way to check if
the collection exists and was successfully
opened, is to check that the coll (OUT)
pointer is not NULL after this function returns
with OCI_SUCCESS. Call OCIHandleFree() to
free the collection handle when it is no longer
required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Note:
This operation does not make
any changes to the database;
however, you can use this
mode to commit an existing
transaction without performing
another round trip.

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Returns
OCI_SUCCESS, if there were no errors while trying to open the collection.
OCI_ERROR, if errors were encountered while trying to open the collection. The OCIError
parameter has the necessary error information.

Usage Notes
None.
Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.4 OCISodaCollList()
Lists the collections in the schema associated with the supplied service context handle
parameter.
Purpose
To list the collections in the schema.
Syntax
sword OCISodaCollList(OCISvcCtx
const OraText
ub4
OCISodaCollCursor
OCIError
ub4

*svchp,
*startname,
stnamelen,
**cur,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

startname (IN)

The collection start name. Can be set to NULL
and stnamelen set to the value 0 to return all
existing collections.

stnamelen (IN)

The length of the collection start name.

cur (OUT)

Allocates the collection cursor handle and
returns it. The collection cursor represents the
collection list. Call OCIHandleFree() to free the
collection cursor handle when it is no longer
required.

errhp (IN/OUT)

The error handle.

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Parameter

Description

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Note:
This operation does not make
any changes to the database;
however, you can use this
mode to commit an existing
transaction without performing
another round trip.

Returns
OCI_SUCCESS, if getting a cursor over all collections in the schema is successful.
OCI_ERROR, if getting a cursor over all collections in the schema is not successful. The
OCIError parameter has the necessary error information.

Usage Notes
None.
Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.5 OCISodaCollGetNext()
Gets the next collection from the collection cursor.
Purpose
Get the next collection from the collection cursor.
Syntax
sword OCISodaCollGetNext(OCISvcCtx
*svchp,
const OCISodaCollCursor *cur,
OCISodaColl
**coll,

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OCIError
ub4

*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

cur (IN)

The collection cursor handle remains valid
when allocated by OCISodaCollList(). Call
OCIHandleFree() to free the collection cursor
handle when it is no longer required.

coll (OUT)

Allocates the collection handle and returns it to
the next collection to be found. Call
OCIHandleFree() to free the collection handle
when it is no longer required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if the next collection is returned from the specified cursor.
OCI_ERROR, if there was an error fetching the next collection. The OCIError parameter

has the necessary error information.
Usage Notes
None.
Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.6 OCISodaCollDrop()
Drops a collection from the database.
Purpose
To drop a collection from the database.
Syntax
sword OCISodaCollDrop(OCISvcCtx
OCISodaColl
boolean
OCIError
ub4

*svchp,
*coll,
*isDropped,
*errhp,
mode);

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Parameters
Parameter

Description

svchp (IN)

The service context handle.

coll (IN)

The collection to be dropped. If coll no longer
references an existing collection, then no error
is returned, but isDropped is FALSE indicating
the drop operation was not successful after the
invocation of OCISodaCollDrop().

isDropped (OUT)

Returns the status of the drop operation: TRUE
if the drop operation is successful, FALSE if the
drop operation is not successful.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if dropping the collection is successful.
OCI_ERROR, if dropping the collection failed. The OCIError parameter has the necessary

error information.
Usage Notes
•

This function only drops the collection; it does not free the collection handle. Call
OCIHandleFree() to free the collection handle to avoid memory leaks.

Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.7 OCISodaDocCreate()
Creates a document.
Purpose
To create a document.
Syntax
sword OCISodaDocCreate (OCIEnv
const void
ub4
ub4
OCISodaDoc
OCIError
ub4

*envhp,
*content,
contentLength,
docFlags,
**document,
*errhp,
mode);

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Parameters
Parameter

Description

envhp (IN)

The environment handle.

content(IN)

A string containing the document content.

contentLength (IN)

The string length of the content parameter.

docFlags (IN)

Used to detect JSON encoding while creating
a document. Valid flag options are:
•
OCI_DEFAULT — If you use this parameter
value then you are, in effect, declaring
that the document content is in the
character set defined by the environment
handle (or environment variable NLS_LANG,
if not set for the handle). If that is not the
case for a given document, then the result
of trying to write the document is
unpredictable.
•
OCI_SODA_DETECT_JSON_ENC —
Automatically detects the encoding of the
document content as either UTF-8,
UTF-16 LE, or UTF-16 BE. If you use this
parameter value then you are, in effect,
declaring that the document content is
either UTF-8, UTF-16 LE, or UTF-16 BE.
If that is not the case for a given
document, then the result of trying to write
the document is unpredictable.

document (OUT)

Allocates and returns the document handle.
Call OCIHandleFree() to free the document
handle when it is no longer required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if the document is successfully created.
OCI_ERROR, if the document creation failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
Example 36-2

Creating a Document

See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36-10

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36.2.8 OCISodaDocCreateWithKey()
Creates a document with a document key and content.
Purpose
To create a document with a document key and content.
Syntax
sword OCISodaDocCreateWithKey(OCIEnv
*envhp,
const void
*content,
ub4
contentLength,
const OraText *key,
ub4
keylen,
ub4
docFlags,
OCISodaDoc **document,
OCIError
*errhp,
ub4
mode);

Parameters
Parameter

Description

envhp (IN)

The environment handle.

content (IN)

A string containing the document content.

contentLength (IN)

The string length of the content parameter.

key (IN)

A string that contains the document key. The
key can be NULL.
For example, in the default case, collection
has auto-generated keys, so you do not want
to set the key on the document (if you do, you
get an error when you pass such a doc to a
write operation, such as insert). You only want
to set a non-NULL key if your collection is
configured with client-assigned keys, which is
not the default.

keylen (IN)

The length of the key string.

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Parameter

Description

docFlags (IN)

The flags used to create a document. Valid
flag options are:
•
OCI_DEFAULT — If you use this parameter
value then you are, in effect, declaring
that the document content is in the
character set defined by the environment
handle (or environment variable NLS_LANG,
if not set for the handle). If that is not the
case for a given document, then the result
of trying to write the document is
unpredictable.
•
OCI_SODA_DETECT_JSON_ENC —
Automatically detects the encoding of the
document content as either UTF-8,
UTF-16 LE, or UTF-16 BE. If you use this
parameter value then you are, in effect,
declaring that the document content is
either UTF-8, UTF-16 LE, or UTF-16 BE.
If that is not the case for a given
document, then the result of trying to write
the document is unpredictable.

document (OUT)

Allocates and returns the document handle.
Call OCIHandleFree() to free the document
handle when it is no longer required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if the document is successfully created.
OCI_ERROR, if the document creation failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
This code snippet shows how to create a document with a key.
Example 36-3

Creating a Document with a Key

See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36-12

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36.2.9 OCISodaDocCreateWithKeyAndMType()
Creates a document with a document key, content, and media type.
Purpose
To create a document with a document key, content, and media type.
Syntax
sword OCISodaDocCreateWithKeyAndMType(OCIEnv
const void
ub4
const OraText
ub4
const OraText
ub4
ub4
OCISodaDoc
OCIError
ub4

*envhp,
*content,
contentLength,
*key,
keylen,
*mediaType,
mediaTypeLength,
docFlags,
**document,
*errhp,
mode);

Parameters
Parameter

Description

envhp (IN)

The environment handle.

content (IN)

A string containing the document content.

contentLength (IN)

The string length of the content parameter.

key (IN)

A string that contains the document key. The
key can be NULL.
For example, in the default case, collection
has auto-generated keys, so you do not want
to set the key on the document (if you do, you
get an error when you pass such a doc to a
write operation, such as insert). You only want
to set a non-NULL key if your collection is
configured with client-assigned keys, which is
not the default.

keylen (IN)

The length of the key string.

mediaType (IN)

A string that contains the document media
type. If no media type value is specified, it
defaults to "application/json". By specifying
a value, you can create non-JSON documents
(using a media type other than "application/
json").

mediaTypeLength (IN)

The length of the media type string.

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Parameter

Description

docFlags (IN)

The flags used to create the document. Valid
flag options are:
•
OCI_DEFAULT — If you use this parameter
value then you are, in effect, declaring
that the document content is in the
character set defined by the environment
handle (or environment variable NLS_LANG,
if not set for the handle). If that is not the
case for a given document, then the result
of trying to write the document is
unpredictable.
•
OCI_SODA_DETECT_JSON_ENC —
Automatically detects the encoding of the
document content as either UTF-8,
UTF-16 LE, or UTF-16 BE. If you use this
parameter value then you are, in effect,
declaring that the document content is
either UTF-8, UTF-16 LE, or UTF-16 BE.
If that is not the case for a given
document, then the result of trying to write
the document is unpredictable.

document (OUT)

Allocates and returns the document handle.
Call OCIHandleFree() to free the document
handle when it is no longer required.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.

Returns
OCI_SUCCESS, if the document is successfully created.
OCI_ERROR, if the document creation failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
Example 36-4

Creating a Document with a Key and Multimedia Type

See the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36-14

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36.2.10 OCISodaFindOneWithKey()
Finds a single document in a collection given a key.
Purpose
To find a single document in a collection given a key.
Syntax
sword OCISodaFindOneWithKey(OCISvcCtx
const OCISodaColl
const OraText
ub4
ub4
OCISodaDoc
OCIError
ub4

*svchp,
*coll,
*key,
keylen,
docFlags,
**doc,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

coll (IN)

The collection to search for the document.

key (IN)

The key used to identify the document.

keylen (IN)

The length of the key.

docFlags (IN)

The following flags control the encoding of the
returned document's content. Valid flag
options are:
•
OCI_DEFAULT — Document content is
returned in the character set defined by
the environment handle (or environment
variable NLS_LANG, if not set for the
handle).
OCI_SODA_AS_STORED — Document
•
content is returned in the character set in
which the content was stored in the
database. Use this parameter value only
for BLOB content. If the content is not
stored in a BLOB instance then an error is
raised.
OCI_SODA_AS_AL32UTF8 — Document
•
content is returned in the character set
AL32UTF8.

doc (OUT)

Allocates and returns the document handle if
the document is found in the collection. If the
document is not found in the collection, a NULL
document is returned and the function returns
OCI_NO_DATA. Call OCIHandleFree() to free the
collection handle when the find operation
completes.

errhp (IN/OUT)

The error handle.

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Parameter

Description

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Note:
This operation does not make
any changes to the database;
however, you can use this
mode to commit an existing
transaction without performing
another round trip.

Returns
OCI_SUCCESS, if the document is found in the specified collection.
OCI_NO_DATA, if the document was not found.
OCI_ERROR, if there was an error in trying to find the document. The OCIError parameter
has the necessary error information.

Usage Notes
None.
Examples
Example 36-5

Finding One Document Using a Key

See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.11 OCISodaInsert()
Inserts a document into a collection.
Purpose
To insert a document into a collection.

36-16

Chapter 36

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Syntax
sword OCISodaInsert(OCISvcCtx
OCISodaColl
OCISodaDoc
OCIError
ub4

*svchp,
*collection,
*document,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collection (IN)

The collection handle for an existing collection.

document (IN)

The handle of the document that is to be
inserted into the collection.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Returns
OCI_SUCCESS, if the document insertion into the specified collection is successful.
OCI_ERROR, if the document insertion failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
See the example in the following link:https://docs.oracle.com/en/database/oracle/
oracle-database/18/adsdc/index.html

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OCI SODA Functions

36.2.12 OCISodaInsertAndGet()
Inserts a document into a collection, returning a result document containing all
document components except for content.
Purpose
To insert a document into a collection, returning a result document containing all
document components except for content. The components generated by SODA
during the insert, such as key (if the collection has auto-assigned keys), last-modified
timestamp, created-on timestamp, and version, are returned as part of the result
document.
Syntax
sword OCISodaInsertAndGet(OCISvcCtx
OCISodaColl
OCISodaDoc
OCIError
ub4

*svchp,
*collection,
**document,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collection (IN)

The collection handle for an existing collection.

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OCI SODA Functions

Parameter

Description

document (IN/OUT)

The handle of the document that is to be
inserted into the collection. Returns the result
document through this same parameter as it is
an IN/OUT.

Caution:
Because the
result document
is returned using
the same
parameter, you
need to save a
reference to the
input document
handle so that
you can free it
later, along with
the result
document
handle, using
OCIHandleFree(
). If you do not
save a reference
to the input
document
handle, it is
overwritten with
a reference to
the result
document, and
the input
document handle
will never be
properly freed
(it's a memory
leak).

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

36-19

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Returns
OCI_SUCCESS, if the document insertion into the specified collection is successful.
OCI_ERROR, if the document insertion failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.13 OCISodaInsertAndGetWithCtnt()
Inserts a document into a collection using just the content, returning a result document
containing all document components except for content.
Purpose
To insert a document into a collection using just the content, returning a result
document containing all document components except for content. The components
generated by SODA during the insert, such as key (if the collection has auto-assigned
keys), last-modified timestamp, created-on timestamp, and version, are returned as
part of the result document.
Syntax
sword OCISodaInsertAndGetWithCtnt(OCISvcCtx
OCISodaColl
const OraText
ub4
const void
ub4
ub4
OCISodaDoc
OCIError
ub4

*svchp,
*collection,
*key,
keyLength,
*content,
contentLength,
docFlags,
**document,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collection (IN)

The collection handle for an existing collection.

key (IN)

A string that contains the document key. Must
be NULL if inserting a document into a
collection configured for auto-generated keys.

keyLength (IN)

The length of the key string. Must be 0 if
inserting a document into a collection
configured for auto-generated keys.

content (IN)

A string containing the document content.

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Parameter

Description

contentLength (IN)

The string length of the content parameter.

docFlags (IN)

The encoding flags used to indicate the
encoding of the supplied document's content.
Valid flag options are:
•
OCI_DEFAULT — If you use this parameter
value then you are, in effect, declaring
that the document content is in the
character set defined by the environment
handle (or environment variable NLS_LANG,
if not set for the handle). If that is not the
case for a given document, then the result
of trying to write the document is
unpredictable.
•
OCI_SODA_DETECT_JSON_ENC —
Automatically detects the encoding of the
document content as either UTF-8,
UTF-16 LE, or UTF-16 BE. If you use this
parameter value then you are, in effect,
declaring that the document content is
either UTF-8, UTF-16 LE, or UTF-16 BE.
If that is not the case for a given
document, then the result of trying to write
the document is unpredictable.

document (OUT)

Allocates and returns a result document
containing all document components except
for content. The components generated by
SODA during the insert, such as key (if the
collection has auto-assigned keys), lastmodified timestamp, created-on timestamp,
and version, are returned as part of the result
document.
If NULL is passed for this parameter, then the
result document is not returned. (In other
words, the function then behaves identically to
the OCISodaInsertWithCtnt() function, which
does not return a result document).

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Returns
OCI_SUCCESS, if the document insertion into the specified collection is successful.

36-21

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OCI SODA Functions

OCI_ERROR, if the document insertion failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.14 OCISodaInsertWithCtnt()
Inserts a document into a collection using just the content.
Purpose
To insert a document into a collection using just the content.
Syntax
sword OCISodaInsertWithCtnt(OCISvcCtx
OCISodaColl
const OraText
ub4
const void
ub4
ub4
OCIError
ub4

*svchp,
*collection,
*key,
keyLength,
*content,
contentLength,
docFlags,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

collection (IN)

The collection handle for an existing collection.

key (IN)

A string that contains the document key. Must
be NULL if inserting a document into a
collection configured for auto-generated keys.

keyLength (IN)

The length of the key string. Must be 0 if
inserting a document into a collection
configured for auto-generated keys.

content (IN)

The content of the document.

contentLength (IN)

The length of the document content.

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Parameter

Description

docFlags (IN)

The encoding flags used to indicate the
encoding of the supplied document's content.
Valid flag options are:
•
OCI_DEFAULT — If you use this parameter
value then you are, in effect, declaring
that the document content is in the
character set defined by the environment
handle (or environment variable NLS_LANG,
if not set for the handle). If that is not the
case for a given document, then the result
of trying to write the document is
unpredictable.
•
OCI_SODA_DETECT_JSON_ENC —
Automatically detects the encoding of the
document content as either UTF-8,
UTF-16 LE, or UTF-16 BE. If you use this
parameter value then you are, in effect,
declaring that the document content is
either UTF-8, UTF-16 LE, or UTF-16 BE.
If that is not the case for a given
document, then the result of trying to write
the document is unpredictable.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
OCI_DEFAULT — Is the default mode. It
•
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Returns
OCI_SUCCESS, if the document insertion into the specified collection is successful.
OCI_ERROR, if the document insertion failed. The OCIError parameter has the necessary

error information.
Usage Notes
None.
Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36-23

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36.2.15 OCISodaRemoveOneWithKey()
Removes a document from a collection given a key.
Purpose
To remove a document from a collection given a key.
Syntax
sword OCISodaRemoveOneWithKey(OCISvcCtx
const OCISodaColl
const OraText
ub4
boolean
OCIError
ub4

*svchp,
*coll,
*key,
keylength,
*isRemoved,
*errhp,
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

coll (IN)

The collection handle for an existing collection.

key (IN)

The key of the document to be removed.

keylength (IN)

The length of key of the document to be
removed.

isRemoved (OUT)

Returns TRUE if a document was found with the
specified key and removed; FALSE if no
document could be found with the specified
key.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Returns
OCI_SUCCESS, if the document with the specified key was not found. OCI_SUCCESS is still
returned (and isRemoved will be set to FALSE). Check that the isRemoved parameter is set
to TRUE to know whether the document has been removed.
OCI_ERROR, if the document removal operation failed during execution due to a SQL
error. The OCIError parameter has the necessary error information.

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OCI SODA Functions

Usage Notes
None.
Examples
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html
.

36.2.16 OCISodaReplOneAndGetWithKey()
Replaces a document in a collection given a key and returns the handle to the result
document.
Purpose
To replace a document in a collection given a key and return the handle to the result
document containing all components except content, including the updated ones, such
as the last-modified timestamp and version.
Syntax
sword OCISodaReplOneAndGetWithKey(OCISvcCtx
*svchp,
const OCISodaColl *coll,
const OraText
*key,
ub4
keylength,
OCISodaDoc
**document,
boolean
*isReplaced,
OCIError
*errhp,
ub4
mode);

Parameters
Parameter

Description

svchp (IN)

The service context handle.

coll (IN)

The collection handle for an existing collection.

key (IN)

The key used to identify the document.

keylength (IN)

The length of the key.

36-25

Chapter 36

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Parameter

Description

document (IN/OUT)

The document handle to use as the
replacement of the document currently in the
collection. Only the content and media type
component from this handle is used during the
replace operation (that is, this operation
replaces the content and media type of the
document in the collection). Other
components, if set on the input document, are
ignored. Returns the result document through
this same parameter as it is an IN/OUT.

Caution:
Because the
result document
is returned using
the same
parameter, you
need to save a
reference to the
input document
handle so that
you can free it
later, along with
the result
document
handle, using
OCIHandleFree(
). If you do not
save a reference
to the input
document
handle, it is
overwritten with
a reference to
the result
document, and
the input
document handle
will never be
properly freed
(it's a memory
leak).

isReplaced (OUT)

Returns TRUE if a document was found with the
specified key and replaced; FALSE if no
document could be found with the specified
key.

errhp (IN/OUT)

The error handle.

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Parameter

Description

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Returns
OCI_SUCCESS, if the document with the specified key was not found. OCI_SUCCESS is still
returned (and isReplaced will be set to FALSE). Check that the isReplaced parameter is
set to TRUE to know whether the document has been replaced.
OCI_ERROR, if the document replacement operation failed during execution due to a SQL
error. The OCIError parameter has the necessary error information.

Usage Notes
None.
Examples
See the example in the following link:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdc/index.html

36.2.17 OCISodaReplOneWithKey()
Replaces a document in a collection given a key.
Purpose
To replace a document in a collection given a key.
Syntax
sword OCISodaReplOneWithKey (OCISvcCtx
const OCISodaColl
const OraText
ub4
OCISodaDoc
boolean
OCIError
ub4

*svchp,
*coll,
*key,
keylength,
*document,
*isReplaced,
*errhp,
mode);

36-27

Chapter 36

OCI SODA Functions

Parameters
Parameter

Description

svchp (IN)

The service context handle.

coll (IN)

The collection handle for an existing collection.

key (IN)

The key used to identify the document.

keylength (IN)

The length of the key.

document (IN)

The document handle to use as the
replacement of the document currently in the
collection. Only the content and media type
component from this handle is used during the
replace operation (that is, this operation
replaces the content and media type of the
document in the collection). Other
components, if set on the input document, are
ignored.

isReplaced (OUT)

Returns TRUE if a document was found with the
specified key and replaced; FALSE if no
document could be found with the specified
key.

errhp (IN/OUT)

The error handle.

mode (IN)

Specifies the mode of execution. Valid modes
are:
•
OCI_DEFAULT — Is the default mode. It
means execute the operation as is with no
special modes.
•
OCI_SODA_COMMIT_ON_SUCCESS — When
an operation executes in this mode and it
completes successfully then the current
transaction is committed after completion.
(Mode parameter
OCI_SODA_COMMIT_ON_SUCCESS acts
analogously to how
OCI_COMMIT_ON_SUCCESS acts for
OCIStmtExecute().)

Returns
OCI_SUCCESS, if the document with the specified key was not found. OCI_SUCCESS is still
returned (and isReplaced will be set to FALSE). Check that the isReplaced parameter is
set to TRUE to know whether the document has been replaced.
OCI_ERROR, if the document replacement operation failed during execution due to a SQL
error. The OCIError parameter has the necessary error information.

Usage Notes
None.
Examples
See the example in OCISodaFindOneWithKey().

36-28

A
Handle and Descriptor Attributes
This appendix describes the attributes for OCI handles and descriptors.
OCI handles and descriptors can be read with OCIAttrGet(), and modified with
OCIAttrSet().

This appendix contains these topics:
•

Conventions

•

Environment Handle Attributes

•

Error Handle Attributes

•

Service Context Handle Attributes

•

Server Handle Attributes
–

Authentication Information Handle Attributes

–

User Session Handle Attributes

•

Administration Handle Attributes

•

Connection Pool Handle Attributes

•

Session Pool Handle Attributes

•

Transaction Handle Attributes

•

Statement Handle Attributes

•

Bind Handle Attributes

•

Define Handle Attributes

•

Describe Handle Attributes

•

Parameter Descriptor Attributes

•

Shard Instance Descriptor Attributes

•

SODA Document Handle Attributes

•

SODA Collection Handle Attributes

•

LOB Descriptor and LOB Locator Attributes

•

Complex Object Attributes

•

–

Complex Object Retrieval Handle Attributes

–

Complex Object Retrieval Descriptor Attributes

Streams Advanced Queuing Descriptor Attributes
–

OCIAQEnqOptions Descriptor Attributes

–

OCIAQDeqOptions Descriptor Attributes

–

OCIAQMsgProperties Descriptor Attributes

–

OCIAQAgent Descriptor Attributes

A-1

Appendix A

Conventions

–
•

•

OCIServerDNs Descriptor Attributes

Subscription Handle Attributes
–

Continuous Query Notification Attributes

–

Continuous Query Notification Descriptor Attributes

–

Notification Descriptor Attributes

–

Invalidated Query Attributes

Direct Path Loading Handle Attributes
–

Direct Path Context Handle (OCIDirPathCtx) Attributes

–

Direct Path Function Context Handle (OCIDirPathFuncCtx) Attributes

–

Direct Path Function Column Array Handle (OCIDirPathColArray) Attributes

–

Direct Path Stream Handle (OCIDirPathStream) Attributes

–

Direct Path Column Parameter Attributes

•

Process Handle Attributes

•

Event Handle Attributes

A.1 Conventions
For each handle type, the attributes that can be read or changed are listed.
Each attribute listing includes the following information:
Mode
The following modes are valid:
READ - The attribute can be read using OCIAttrGet().
WRITE - The attribute can be modified using OCIAttrSet().
READ/WRITE - The attribute can be read using OCIAttrGet(), and it can be modified
using OCIAttrSet().
Description
This is a description of the purpose of the attribute.
Attribute Data Type
This is the data type of the attribute. If necessary, a distinction is made between the
data type for READ and WRITE modes.
Valid Values
In some cases, only certain values are allowed, and they are listed here.
Example
In some cases an example is included.

A.2 Environment Handle Attributes
Lists and describes environment handle attributes.
The following attributes are used for the environment handle.

A-2

Appendix A

Environment Handle Attributes

OCI_ATTR_ALLOC_DURATION
Mode
READ/WRITE
Description
This attribute sets the value of OCI_DURATION_DEFAULT for allocation durations for the
application associated with the environment handle.
Attribute Data Type
OCIDuration */OCIDuration

OCI_ATTR_BIND_DN
Mode
READ/WRITE
Description
The login name (DN) to use when connecting to the LDAP server.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_CACHE_ARRAYFLUSH
Mode
READ/WRITE
Description
When this attribute is set to TRUE, during OCICacheFlush() the objects that belong to the
same table are flushed, which can considerably improve performance. An attribute
value of TRUE should only be used when the order in which the objects are flushed is
not important. When the attribute value is set to TRUE, it is not guaranteed that the
order in which the objects are marked dirty is preserved.

See Also:
Object Cache Parameters and About Flushing Changes to the Server
Attribute Data Type
boolean */boolean

OCI_ATTR_CACHE_MAX_SIZE
Mode
READ/WRITE
Description
Sets the maximum size (high watermark) for the client-side object cache as a
percentage of the optimal size. Usually you can set the value at 10%, the default, of
the optimal size, OCI_ATTR_CACHE_OPT_SIZE. Setting this attribute to 0 results in a value
of 10 being used. The object cache uses the maximum and optimal values for freeing
unused memory in the object cache.

A-3

Appendix A

Environment Handle Attributes

See Also:
Object Cache Parameters
Attribute Data Type
ub4 */ub4

OCI_ATTR_CACHE_OPT_SIZE
Mode
READ/WRITE
Description
Sets the optimal size for the client-side object cache in bytes. The default value is 8
megabytes (MB). Setting this attribute to 0 results in a value of 8 MB being used.

See Also:
Object Cache Parameters
Attribute Data Type
ub4 */ub4

OCI_ATTR_ENV_CHARSET_ID
Mode
READ
Description
Local (client-side) character set ID. Users can update this setting only after creating
the environment handle but before calling any other OCI functions. This restriction
ensures the consistency among data and metadata in the same environment handle.
When character set ID is UTF-16, an attempt to get this attribute is invalid.
Attribute Data Type
ub2 *

OCI_ATTR_ENV_NCHARSET_ID
Mode
READ
Description
Local (client-side) national character set ID. Users can update this setting only after
creating the environment handle but before calling any other OCI functions. This
restriction ensures the consistency among data and metadata in the same
environment handle. When character set ID is UTF-16, an attempt to get this attribute
is invalid.
Attribute Data Type
ub2 *

A-4

Appendix A

Environment Handle Attributes

OCI_ATTR_ENV_NLS_LANGUAGE
Mode
READ/WRITE
Description
The name of the language used for the database sessions created from the current
environment handle. While getting this value, users should pass an allocated buffer,
which will be filled with the language name.
Attribute Data Type
oratext ** or oratext *
OCI_ATTR_ENV_NLS_TERRITORY
Mode
READ/WRITE
Description
The name of the territory used for the database sessions created from the current
environment handle. While getting this value, users should pass an allocated buffer,
which will be filled with the territory name.
Attribute Data Type
oratext ** or oratext *
OCI_ATTR_ENV_UTF16
Mode
READ
Description
Encoding method is UTF-16. The value 1 means that the environment handle is
created when the encoding method is UTF-16, whereas 0 means that it is not. This
attribute value can only be set by the call to OCIEnvCreate() and cannot be changed
later.
Attribute Data Type
ub1 *

OCI_ATTR_EVTCBK
Mode
WRITE
Description
This attribute registers an event callback function.

See Also:
HA Event Notification

A-5

Appendix A

Environment Handle Attributes

Attribute Data Type
OCIEventCallback

OCI_ATTR_EVTCTX
Mode
WRITE
Description
This attribute registers a context passed to an event callback.

See Also:
HA Event Notification
Attribute Data Type
void *
OCI_ATTR_HEAPALLOC
Mode
READ
Description
The current size of the memory allocated from the environment handle. This may help
you track where memory is being used most in an application.
Attribute Data Type
ub4 *

OCI_ATTR_LDAP_AUTH
Mode
READ/WRITE
Description
The authentication mode. The following are the valid values:
0x0: No authentication; anonymous bind.
0x1: Simple authentication; user name and password authentication.
0x5: SSL connection with no authentication.
0x6: SSL: only server authentication required.
0x7: SSL: both server authentication and client authentication are required.
0x8: Authentication method is determined at run time.
Attribute Data Type
ub2 */ub2

OCI_ATTR_LDAP_CRED
Mode
READ/WRITE

A-6

Appendix A

Environment Handle Attributes

Description
If the authentication method is "simple authentication" (user name and password
authentication), then this attribute holds the password to use when connecting to the
LDAP server.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_LDAP_CTX
Mode
READ/WRITE
Description
The administrative context of the client. This is usually the root of the Oracle
Database LDAP schema in the LDAP server.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_LDAP_HOST
Mode
READ/WRITE
Description
The name of the host on which the LDAP server runs.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_LDAP_PORT
Mode
READ/WRITE
Description
The port on which the LDAP server is listening.
Attribute Data Type
ub2 */ub2

OCI_ATTR_OBJECT
Mode
READ
Description
Returns TRUE if the environment was initialized in object mode.
Attribute Data Type
boolean *

A-7

Appendix A

Environment Handle Attributes

OCI_ATTR_PINOPTION
Mode
READ/WRITE
Description
This attribute sets the value of OCI_PIN_DEFAULT for the application associated with the
environment handle.
For example, if OCI_ATTR_PINOPTION is set to OCI_PIN_RECENT, and OCIObjectPin() is
called with the pin_option parameter set to OCI_PIN_DEFAULT, the object is pinned in
OCI_PIN_RECENT mode.
Attribute Data Type
OCIPinOpt */OCIPinOpt

OCI_ATTR_OBJECT_NEWNOTNULL
Mode
READ/WRITE
Description
When this attribute is set to TRUE, newly created objects have non-NULL attributes.

See Also:
About Creating Objects
Attribute Data Type
boolean */boolean

OCI_ATTR_OBJECT_DETECTCHANGE
Mode
READ/WRITE
Description
When this attribute is set to TRUE, applications receive an ORA-08179 error when
attempting to flush an object that has been modified in the server by another
committed transaction.

See Also:
About Implementing Optimistic Locking
Attribute Data Type
boolean */boolean

OCI_ATTR_PIN_DURATION
Mode
READ/WRITE

A-8

Appendix A

Error Handle Attributes

Description
This attribute sets the value of OCI_DURATION_DEFAULT for pin durations for the
application associated with the environment handle.
Attribute Data Type
OCIDuration */OCIDuration

OCI_ATTR_SHARED_HEAPALLOC
Mode
READ
Description
Returns the size of the memory currently allocated from the shared pool. This attribute
works on any environment handle, but the process must be initialized in shared mode
to return a meaningful value. This attribute is read as follows:
ub4 heapsz = 0;
OCIAttrGet((void *)envhp, (ub4)OCI_HTYPE_ENV,
(void *) &heapsz, (ub4 *) 0,
(ub4)OCI_ATTR_SHARED_HEAPALLOC, errhp);

Attribute Data Type
ub4 *

OCI_ATTR_SUBSCR_PORTNO
Mode
READ/WRITE
Description
The client port used to receive notifications. It is set on the client's environment
handle.
Attribute Data Type
ub4 *

OCI_ATTR_WALL_LOC
Mode
READ/WRITE
Description
If the authentication method is SSL authentication, this attribute contains the location
of the client wallet.
Attribute Data Type
oratext **/oratext *

A.3 Error Handle Attributes
Lists and describes error handle attributes.
The following attributes are used for the error handle.

A-9

Appendix A

Service Context Handle Attributes

OCI_ATTR_DML_ROW_OFFSET
Mode
READ
Description
Returns the offset (into the DML array) at which the error occurred.
Attribute Data Type
ub4 *

OCI_ATTR_ERROR_IS_RECOVERABLE
Mode
READ
Description
This attribute is set to TRUE if the error in the error handle is recoverable. If the error is
not recoverable, it is set to FALSE.
Attribute Data Type
Boolean *

A.4 Service Context Handle Attributes
Lists and describes service context handle attributes.
The following attributes are used for service context handle.
OCI_ATTR_CALL_TIMEOUT
Mode
READ/WRITE
Description
A database round-trip call using the service context times out within the specified time
in milli-seconds, if not completed. When the call times out, a network timeout error is
returned. This attribute can be set dynamically. Setting this value stays effective for all
subsequent round-trip calls executed using the same service context until a different
value is set. To remove the timeout, the value must be set to 0.
This is a client-only change. So, for using this feature, you must use a release 18c
client. This feature is database version agnostic, that is, you can use this feature with
any supported version of the database.
Timeout values set in different places are effective according to the following order of
precedence (where 1 is the highest precedence):
1.
2.

Call timeout set on the OCI handle using OCIAttrSet().
Timeout set with the OCI attributes, OCI_ATTR_SEND_TIMEOUT and
OCI_ATTR_RECEIVE_TIMEOUT.

3.

Timeout set in the sqlnet.ora file with the parameters, SQLNET.RECV_TIMEOUT and
SQLNET.SEND_TIMEOUT.

Error returned to the application:

A-10

Appendix A

Service Context Handle Attributes

ORA-03136 inbound connection timed out

The Call timeout is on each individual round-trip between OCI and Oracle Database.
Each OCI method or operation may require zero or more round-trips to Oracle
Database. The timeout value applies to each round-trip individually, not to the sum of
all round-trips. Time spent processing in OCI before or after the completion of each
round-trip is not counted.
•

If the time from the start of any round-trip to the completion of the same round-trip
exceeds the timeout value, then the operation is halted and an Oracle error is
returned.

•

In the case where an OCI operation requires more than one round-trip and each
round-trip takes less than the timeout value, then no timeout occurs, even if the
sum of all round-trip calls exceeds the timeout value.

•

If no round-trip is required, the operation will never be interrupted.

After a timeout occurs, OCI attempts to clean up the internal connection state. The
cleanup is allowed to take another timeout value. If the cleanup was successful, an
ORA-3136 will be returned and the application can continue to use the connection.
For small values of the timeout value, the connection cleanup may not complete
successfully within the additional timeout period. In this case an ORA-3114 is returned
and the connection will no longer be usable. It should be released.
Alternatively, the OCI_ATTR_BREAK_ON_NET_TIMEOUT attribute can additionally be set to
FALSE. This setting drops the connection, eliminating calls to OCIBreak() and OCIReset()
when a timeout occurs.

Note:
When call timeout is set, then ora-12161 may be returned while reading a
large amount of data. This error must be treated as ora-3136.
Attribute Data Type
ub4*/ub4

Example
static void func1( )
{
sword status = 0;
OCIStmt *stmthp = (OCIStmt *)0;
OraText *sqlStmt = (OraText *)"SELECT EMPNO FROM SCOTT.EMP";
ub4 set_timeout= 200; /* in milliseconds */
ub4 get_timeout = 0;
Checkerr (errhp, \
OCIStmtPrepare2 ((OCISvcCtx *)svchp, (OCIStmt **)&stmthp, \
(OCIError *)errhp, (OraText *)sqlStmt, (ub4)strlen((char *)sqlStmt), \
(OraText *)NULL, (ub4) 0, (ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT), \
(OraText *)"OCIStmtPrepare2");
/* Set the call Timeout (in milliseconds) */
Checkerr (errhp,
OCIAttrSet(svchp, (ub4) OCI_HTYPE_SVCCTX,
(dvoid *) &set_timeout, (ub4) 0,

A-11

Appendix A

Service Context Handle Attributes

(ub4) OCI_ATTR_CALL_TIMEOUT, errhp),
"OCIAttrSet OCI_ATTR_CALL_TIMEOUT");
if ((status = OCIStmtExecute ((OCISvcCtx *)svchp, \
(OCIStmt *)stmthp, (OCIError *)errhp, (ub4)1, (ub4)0, \
(OCISnapshot *)0, (OCISnapshot *)0, (ub4)OCI_DEFAULT)) \
!= OCI_SUCCESS)
{
printf ( "OCIStmtExecute Failed with timeout: %dms\n", set_timeout);
Checkerr (errhp, status,(OraText *)"OCIStmtExecute");
}
/* Get the call Timeout (in milliseconds) */
Checkerr (errhp,
OCIAttrGet(svchp, (ub4) OCI_HTYPE_SVCCTX,
(dvoid *) &get_timeout, (ub4) 0,
(ub4) OCI_ATTR_CALL_TIMEOUT, errhp),
"OCIAttrGet OCI_ATTR_CALL_TIMEOUT");
Checkerr (errhp, \
OCIStmtRelease ((OCIStmt *)stmthp, (OCIError *)errhp,(dvoid *)NULL, \
0, OCI_DEFAULT), (oratext *)"StmtRelease");
} /* End of func1 */

OCI_ATTR_ENV
Mode
READ
Description
Returns the environment context associated with the service context.
Attribute Data Type
OCIEnv **

OCI_ATTR_INSTNAME
See the OCI_ATTR_INSTNAME attribute in Shard Instance Descriptor Attributes for more
information about its use on the service context.
OCI_ATTR_IN_V8_MODE
Mode
READ
Description
Allows you to determine whether an application has switched to Oracle release 7
mode (for example, through an OCISvcCtxToLda() call). A nonzero (TRUE) return value
indicates that the application is currently running in Oracle release 8 mode, a zero
(false) return value indicates that the application is currently running in Oracle release
7 mode.
Attribute Data Type
ub1 *

Example
The following code sample shows how this attribute is used:

A-12

Appendix A

Service Context Handle Attributes

in_v8_mode = 0;
OCIAttrGet ((void *)svchp, (ub4)OCI_HTYPE_SVCCTX, (ub1 *)&in_v8_mode,
(ub4) 0, OCI_ATTR_IN_V8_MODE, errhp);
if (in_v8_mode)
fprintf (stdout, "In V8 mode\n");
else
fprintf (stdout, "In V7 mode\n");

OCI_ATTR_MAX_CHARSET_RATIO
Mode
READ
Description
Returns the maximum character set expansion ratio from server to client character
set. Using these attributes is useful in scenarios where there are different character
sets between server and client. This is useful to allocate optimal memory of buffers
before conversion so that when data is returned from the database, sufficient space
can be allocated to hold it.
Attribute Data Type
ub4 *
Example
size_t cratio;
OCIAttrGet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX, (size_t *)&cratio, (ub4) 0,
OCI_ATTR_MAX_CHARSET_RATIO, errhp);
printf("Conversion ratio from server to client character set is %d\n", cratio);

OCI_ATTR_MAX_NCHARSET_RATIO
Mode
READ
Description
Returns the maximum character set expansion ratio from server to client national
character set. Using these attributes is useful in scenarios where there are different
national character sets between server and client. This is useful to allocate optimal
memory of buffers before conversion so that when data is returned from the database,
sufficient space can be allocated to hold it.
Attribute Data Type
ub4 *
Example
size_t cratio;
OCIAttrGet((void *)svchp, (ub4)OCI_HTYPE_SVCCTX, (size_t *)&cratio, (ub4) 0,
OCI_ATTR_MAX_NCHARSET_RATIO, errhp);
printf("Conversion ratio from server to client ncharset is %d\n", cratio);

OCI_ATTR_SERVER
Mode
READ/WRITE

A-13

Appendix A

Service Context Handle Attributes

Description
When read, returns the pointer to the server context attribute of the service context.
When changed, sets the server context attribute of the service context.
Attribute Data Type
OCIServer ** / OCIServer *
OCI_ATTR_SESSION
Mode
READ/WRITE
Description
When read, returns the pointer to the authentication context attribute of the service
context.
When changed, sets the authentication context attribute of the service context.
Attribute Data Type
OCISession **/ OCISession *
OCI_ATTR_STMTCACHE_CBK
Mode
READ/WRITE
Description
Used to get and set the application's callback function on the OCISvcCtx handle. This
function, if registered on OCISvcCtx, is called when a statement in the statement cache
belonging to this service context is purged or when the session is ended.
The callback function must be of this prototype:
sword (*OCICallbackStmtCache)(void *ctx, OCIStmt *stmt, ub4 mode)
ctx: IN argument. This is the same as the context the application has set on the

current statement handle.
stmt: IN argument. This is the statement handle that is being purged from the cache.
mode: IN argument. This is the mode in which the callback function is being called.
Currently only one value is supported, OCI_CBK_STMTCACHE_STMTPURGE, which means the

callback is being called during purging of the current statement.
Attribute Data Type
sword (*OCICallbackStmtCache)(void *ctx, OCIStmt *stmt, ub4 mode)

OCI_ATTR_STMTCACHESIZE
Mode
READ/WRITE
Description
The default value of the statement cache size is 20 statements, for a statement
cache-enabled session. The user can increase or decrease this value by setting this
attribute on the service context handle. This attribute can also be used to enable or
disable statement caching for the session, pooled or nonpooled. Statement caching
can be enabled by setting the attribute to a nonzero size and disabled by setting it to
zero.

A-14

Appendix A

Server Handle Attributes

Attribute Data Type
ub4 */ ub4
OCI_ATTR_TRANS
Mode
READ/WRITE
Description
When read, returns the pointer to the transaction context attribute of the service
context.
When changed, sets the transaction context attribute of the service context.
Attribute Data Type
OCITrans ** / OCITrans *
OCI_ATTR_VARTYPE_MAXLEN_COMPAT
Mode
READ
Description
Returns OCI_ATTR_MAXLEN_COMPAT_EXTENDED if the init.ora parameter max_string_size =
extended or returns OCI_ATTR_MAXLEN_COMPAT_STANDARD if the init.ora parameter
max_string_size = standard.
Attribute Data Type
ub1 *

A.5 Server Handle Attributes
Lists and describes server handle attributes.
The following attributes are used for the server handle.

See Also:
The following event handle attributes are also available for the server handle:
•

OCI_ATTR_DBDOMAIN

•

OCI_ATTR_DBNAME

•

OCI_ATTR_INSTNAME

•

OCI_ATTR_INSTSTARTTIME

•

OCI_ATTR_SERVICENAME

OCIXStreamOutLCRReceive() for more information about using the following
attributes

A-15

Appendix A

Server Handle Attributes

OCI_ATTR_ACCESS_BANNER
Mode
READ
Description
Displays an unauthorized access banner from a file.
Attribute Data Type
oratext **
OCI_ATTR_BREAK_ON_NET_TIMEOUT
Mode
READ/WRITE
Description
This attribute determines whether OCI sends a break after a network time out or not.
Attribute Data Type
ub1 *
OCI_ATTR_ENV
Mode
READ
Description
Returns the environment context associated with the server context.
Attribute Data Type
OCIEnv **

OCI_ATTR_EXTERNAL_NAME
Mode
READ/WRITE
Description
The external name is the user-friendly global name stored in sys.props$.value$,
where name = 'GLOBAL_DB_NAME'. It is not guaranteed to be unique unless all databases
register their names with a network directory service.
Database names can be exchanged with the server for distributed transaction
coordination. Server database names can only be accessed only if the database is
open at the time the OCISessionBegin() call is issued.
Attribute Data Type
oratext **/ oratext *
OCI_ATTR_FOCBK
Mode
READ/WRITE

A-16

Appendix A

Server Handle Attributes

Description
Sets the failover callback to the callback definition structure of type OCIFocbkStruct as
part of failover callback registration and unregistration on the server context handle.

See Also:
Transparent Application Failover in OCI
Attribute Data Type
OCIFocbkStruct *

OCI_ATTR_INTERNAL_NAME
Mode
READ/WRITE
Description
Sets the client database name that is recorded when performing global transactions.
The DBA can use the name to track transactions that may be pending in a prepared
state due to failures.
Attribute Data Type
oratext ** / oratext *
OCI_ATTR_INSTNAME
See the OCI_ATTR_INSTNAME attribute in Shard Instance Descriptor Attributes for more
information about its use as a server handle attribute.
OCI_ATTR_IN_V8_MODE
Mode
READ
Description
Allows you to determine whether an application has switched to Oracle release 7
mode (for example, through an OCISvcCtxToLda() call). A nonzero (TRUE) return value
indicates that the application is currently running in Oracle release 8 mode, a zero
(FALSE) return value indicates that the application is currently running in Oracle release
7 mode.
Attribute Data Type
ub1 *

OCI_ATTR_NONBLOCKING_MODE
Mode
READ/WRITE
Description
This attribute determines the blocking mode. When read, the attribute value returns
TRUE if the server context is in nonblocking mode. When set, it toggles the nonblocking
mode attribute. You must set this attribute only after OCISessionBegin() or OCILogon2()
has been called. Otherwise, an error is returned.

A-17

Appendix A

Server Handle Attributes

Attribute Data Type
ub1 */ub1

See Also:
Nonblocking Mode in OCI

OCI_ATTR_RECEIVE_TIMEOUT
Mode
READ/WRITE
Description
Time specified in milliseconds that a client waits for response data from the database
server. When set to a value of zero, the timeout functionality is disabled and the client
may wait a long period of time for a response from a database server.
The semantics of this attribute is the same as that of SQLNET.RECV_TIMEOUT that can be
specified in the sqlnet.ora file. When set on the server handle, the value overrides the
one specified in the sqlnet.ora file.
Attribute Data Type
ub4*/ub4

OCI_ATTR_SEND_TIMEOUT
Mode
READ/WRITE
Description
Time specified in milliseconds that a client waits to complete send operations to the
database server. When set to a value of zero, the timeout functionality is disabled and
the client may wait a long period of time to complete sending the data to the database
server.
The semantics of this attribute is the same as that of SQLNET.SEND_TIMEOUT that can be
specified in the sqlnet.ora file. When set on the server handle, the value overrides the
one specified in the sqlnet.ora file.
Attribute Data Type
ub4*/ub4

OCI_ATTR_SERVER_GROUP
Mode
READ/WRITE
Description
An alphanumeric string not exceeding 30 characters specifying the server group. This
attribute can only be set after calling OCIServerAttach().

A-18

Appendix A

Server Handle Attributes

See Also:
Password and Session Management
Attribute Data Type
oratext **/oratext *

OCI_ATTR_SERVER_STATUS
Mode
READ
Description
Returns the current status of the connection by doing a light weight connection health
check. Values are:
•

OCI_SERVER_NORMAL - The connection is alive.

•

OCI_SERVER_NOT_CONNECTED - The connection has been terminated.

Attribute Data Type
ub4 *
Example
The following code sample shows how this parameter is used:
ub4 serverStatus = 0
OCIAttrGet((void *)srvhp, OCI_HTYPE_SERVER,
(void *)&serverStatus, (ub4 *)0, OCI_ATTR_SERVER_STATUS, errhp);
if (serverStatus == OCI_SERVER_NORMAL)
printf("Connection is up.\n");
else if (serverStatus == OCI_SERVER_NOT_CONNECTED)
printf("Connection is down.\n");

OCI_ATTR_TAF_ENABLED
Mode
READ
Description
Set to TRUE if the server handle is TAF-enabled and FALSE if not.

See Also:
Custom Pooling: Tagged Server Handles
Attribute Data Type
boolean *
OCI_ATTR_USER_MEMORY
Mode
READ

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Appendix A

Server Handle Attributes

Description
If the handle was allocated with extra memory, this attribute returns a pointer to the
user memory. A NULL pointer is returned for those handles not allocated with extra
memory.

See Also:
Custom Pooling: Tagged Server Handles
Attribute Data Type
void *

A.5.1 Authentication Information Handle Attributes
Lists and describes authentication information handle attributes.
These attributes also apply to the user session handle.

See Also:
User Session Handle Attributes

OCI_ATTR_FIXUP_CALLBACK
Mode
READ/WRITE
Description
Specifies on the authentication handle attribute the callback passed to
OCISessionGet() for applications not using an OCISessionPool or using custom pools.
For applications using OCISessionPool, this attribute must be set on the
authentication handle, which in turn must be set on the session pool handle as the
attribute OCI_ATTR_SPOOL_AUTH.

See Also:
•

Session Pool Handle Attributes for more information

•

PL/SQL Callback for Session State Fix Up for more information

Attribute Data Type
oratext * to be provided in the format schma.package.callback_function

A-20

Appendix A

Server Handle Attributes

A.5.2 User Session Handle Attributes
Lists and describes user session handle attributes.
The following user session handle attributes also apply to the authentication
information handle.
OCI_ATTR_ACTION
Mode
WRITE
Description
The name of the current action within the current module. Can be set to NULL. When
the current action terminates, set this attribute again with the name of the next action,
or NULL if there is no next action. Can be up to 32 bytes long.
Attribute Data Type
oratext *

Example
OCIAttrSet(session, OCI_HTYPE_SESSION,(void *)"insert into employees",
(ub4)strlen("insert into employees"), OCI_ATTR_ACTION, error_handle);

OCI_ATTR_APPCTX_ATTR

Note:
This attribute is not supported with database resident connection pooling.

Mode
WRITE
Description
Specifies an attribute name of the externally initialized context.

See Also:
Session Handle Attributes Used to Set an Externally Initialized Context
Attribute Data Type
oratext *

OCI_ATTR_APPCTX_LIST

Note:
This attribute is not supported with database resident connection pooling.

A-21

Appendix A

Server Handle Attributes

Mode
READ
Description
Gets the application context list descriptor for the session.
Attribute Data Type
OCIParam **

OCI_ATTR_APPCTX_NAME

Note:
This attribute is not supported with database resident connection pooling.

Mode
WRITE

See Also:
Session Handle Attributes Used to Set an Externally Initialized Context
Description
Specifies the namespace of the externally initialized context.
Attribute Data Type
oratext *

OCI_ATTR_APPCTX_SIZE

Note:
This attribute is not supported with database resident connection pooling.

Mode
WRITE
Description
Initializes the externally initialized context array size with the number of attributes.
Attribute Data Type
ub4

A-22

Appendix A

Server Handle Attributes

OCI_ATTR_APPCTX_VALUE

Note:
This attribute is not supported with database resident connection pooling.

Mode
WRITE
Description
Specifies a value of the externally initialized context.
Attribute Data Type
oratext *

See Also:
Session Handle Attributes Used to Set an Externally Initialized Context
OCI_ATTR_AUDIT_BANNER
Mode
READ
Description
Displays a user actions auditing banner from a file.
Attribute Data Type
oratext **
OCI_ATTR_AUTOTUNING_ENABLED
Mode
READ
Description
Checks if the client session has OCI auto tuning enabled on OCI client statement
caching.
Attribute Data Type
ub4 *

OCI_ATTR_CALL_TIME
Mode
READ
Description
Returns the server-side time for the preceding call in microseconds.

A-23

Appendix A

Server Handle Attributes

Attribute Data Type
ub8 *

OCI_ATTR_CERTIFICATE
Mode
WRITE
Description
Specifies the certificate of the client for use in proxy authentication. Certificate-based
proxy authentication using OCI_ATTR_CERTIFICATE will not be supported in future Oracle
Database releases. Use OCI_ATTR_DISTINGUISHED_NAME or OCI_ATTR_USERNAME attribute
instead.
Attribute Data Type
ub1 *

OCI_ATTR_CLIENT_IDENTIFIER
Mode
WRITE
Description
Specifies the user identifier in the session handle. Can be up to 64 bytes long. The
value is automatically truncated if the supplied input is more than 64 bytes. It can
contain the user name, but do not include the password for security reasons. The first
character of the identifier should not be ':'. If it is, the behavior is unspecified.
Attribute Data Type
oratext *

Example
OCIAttrSet(session, OCI_HTYPE_SESSION,(void *)"janedoe",
(ub4)strlen("janedoe"), OCI_ATTR_CLIENT_IDENTIFIER,
error_handle);

OCI_ATTR_CLIENT_INFO
Mode
WRITE
Description
Stores additional client application information. Can also be set by the
DBMS_APPLICATION_INFO package. It is stored in the V$SESSION view. Can be up to 64
bytes long.
Attribute Data Type
oratext *

OCI_ATTR_COLLECT_CALL_TIME
Mode
READ/WRITE

A-24

Appendix A

Server Handle Attributes

Description
When set to TRUE, causes the server to measure call time, in milliseconds, for each
subsequent OCI call.
Attribute Data Type
boolean */boolean
OCI_ATTR_CONNECTION_CLASS
Mode
READ/WRITE
Description
This attribute of OCIAuthInfo handle explicitly names the connection class (a string of
up to 128 characters) for a database resident connection pool.
Attribute Data Type
oratext **/oratext *
OCI_ATTR_CURRENT_SCHEMA
Mode
READ/WRITE
Description
Calling OCIAttrSet() with this attribute has the same effect as the SQL command
ALTER SESSION SET CURRENT_SCHEMA, if the schema name and the session exist. The
schema is altered on the next OCI call that does a round-trip to the server, avoiding
an extra round-trip. If the new schema name does not exist, the same error is
returned as the error returned from ALTER SESSION SET CURRENT_SCHEMA. The new
schema name is placed before database objects in DML or DDL commands that you
then enter.
When a client using this attribute communicates with a server that has a software
release earlier than Oracle Database 10g Release 2, the OCIAttrSet() call is ignored.
This attribute is also readable by OCIAttrGet().
Attribute Data Type
oratext */oratext *

Example
text schema[] = "hr";
err = OCIAttrSet( (void ) mysessp, OCI_HTYPE_SESSION, (void *)schema,
(ub4)strlen( (char *)schema), OCI_ATTR_CURRENT_SCHEMA, (OCIError *)myerrhp);

OCI_ATTR_DBOP
Mode
Write
Description
The name of the database operation set by the client application to be monitored in
the database. When you want to end monitoring the current running database
operation, set the value to NULL. Can be up to 30 bytes long.

A-25

Appendix A

Server Handle Attributes

See Also:
Attributes for End-to-End Application Tracing
Oracle Database SQL Tuning Guide
Oracle Database 2 Day + Performance Tuning Guide
Attribute Data Type
oratext *

Example
(void) OCIAttrSet((dvoid *) sess1, (ub4) OCI_HTYPE_SESSION,
(dvoid *) dbopname, (ub4) strlen((char *)dbopname),
(ub4) OCI_ATTR_DBOP, errhp);

OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE
Mode
READ/WRITE
Description
Allows the user to enable prefetching for all the LOB locators fetched in the session.
Specifies the default prefetch buffer size for each LOB locator.
Attribute Data Type
ub4 */ub4

OCI_ATTR_DISTINGUISHED_NAME
Mode
WRITE
Description
Specifies the distinguished name of the client for use in proxy authentication.
Attribute Data Type
oratext *

OCI_ATTR_DRIVER_NAME
Mode
READ/WRITE
Description
Specifies the name of the driver layer using OCI, such as JDBC, ODBC, PHP,
SQL*Plus, and so on. Names starting with "ORA$" are reserved also. A future
application can choose its own name and set it as an aid to fault diagnosability. Set
this attribute before executing OCISessionBegin(). Pass an array containing up to 9
single-byte characters, including the null terminator. This data is not validated and is
passed directly to the server to be displayed in a V$SESSION_CONNECT_INFO or
GV$SESSION_CONNECT_INFO view. OCI accepts driver names of up to 30 characters,
which are displayed in these views. For older databases, only the first 8 characters
are displayed.

A-26

Appendix A

Server Handle Attributes

Attribute Data Type
oratext **/oratext *

Example
...
oratext client_driver[9];
...
checkerr(errhp, OCIAttrSet(authp, OCI_HTYPE_SESSION,
client_driver, (ub4)(strlen(client_driver)),
OCI_ATTR_DRIVER_NAME, errhp));
checkerr(errhp, OCISessionBegin(svchp, errhp, authp, OCI_CRED_RDBMS, OCI_DEFAULT);
...

OCI_ATTR_EDITION
Mode
READ/WRITE
Description
Specifies the edition to be used for this session. If a value for this attribute has not
been set explicitly, then the value in the environment variable ORA_EDITION is returned.
Attribute Data Type
oratext *
OCI_ATTR_INITIAL_CLIENT_ROLES
Mode
WRITE
Description
Specifies the role or roles that the client is to initially possess when the application
server connects to an Oracle database on its behalf.
Attribute Data Type
oratext **.
OCI_ATTR_LTXID
Mode
READ
Description
This attribute is defined for the session handle and is used to override the default
LTXID (logical transaction ID). Applications that associate the logical session with the
web user may want to explicitly attach the LTXID to a physical session and explicitly
detach the LTXID when the request is complete.
In READ mode, this attribute is used to retrieve the LTXID embedded in the OCISession
handle.
Attribute Data Type
ub1 * (with length; value is copied; is really a ub1 array)

A-27

Appendix A

Server Handle Attributes

OCI_ATTR_MAX_OPEN_CURSORS
Mode
READ
Description
The maximum number of SQL statements that can be opened in one session. On the
server's parameter file, this value is set using the parameter open_cursors. The OCI
user should leave some threshold and not reach this limit because the server can also
open internal statements (cursors) as part of processing user calls. Applications can
use this attribute to limit the number of statement handles opened on a given session.
This attribute returns a proper value only when connected to a 12.1 server or later.
If the cursors in the server session exceed the open cursor setting, then the server
returns an error to the client saying that the value for max cursors is exceeded.
Also, note that this value should only be looked at from the session handle after an
OCISessionGet() or equivalent login call has been done.
Attribute Data Type
ub4 *

Example
OCIAttrGet((void *)usrhp, OCI_HTYPE_SESSION,
(void *)&ub4localvariable, (ub4 *)0, OCI_ATTR_MAX_OPEN_CURSORS, errhp);

OCI_ATTR_MIGSESSION
Mode
READ/WRITE
Description
Specifies the session identified for the session handle. Allows you to clone a session
from one environment to another, in the same process or between processes. These
processes can be on the same system or different systems. For a session to be
cloned, the session must be authenticated as migratable.

See Also:
Password and Session Management
Attribute Data Type
ub1 *

Example
The following code sample shows how this attribute is used:
OCIAttrSet ((void *) authp, (ub4)OCI_HTYPE_SESSION, (void *) mig_session,
(ub4) sz, (ub4)OCI_ATTR_MIGSESSION, errhp);

OCI_ATTR_MODULE
Mode
WRITE

A-28

Appendix A

Server Handle Attributes

Description
The name of the current module running in the client application. When the current
module terminates, call with the name of the new module, or use NULL if there is no
new module. Can be up to 48 bytes long.
Attribute Data Type
oratext *

Example
OCIAttrSet(session, OCI_HTYPE_SESSION,(void *)"add_employee",
(ub4)strlen("add_employee"), OCI_ATTR_MODULE, error_handle);

OCI_ATTR_ORA_DEBUG_JDWP
Mode
WRITE
Description
Specifies the external debugger's location the database session is to connect to after
logon. This allows the user to initiate debugging of the database application.
The format of the attribute is a list of parameter names and values separated by semicolons. The parameters will be passed to the DBMS_
DEBUG_JDWP_CUSTOM.CONNECT_DEBUGGER package API to connect the database session to
the debugger. The parameter name can be a quoted or unquoted PL/SQL identifier.
The parameter value is a character string, either quoted by single-quotes, or
unquoted, which is terminated by a semi-colon. To escape a single quote in a quoted
string, use two consecutive single quotes. No space is allowed anywhere between the
parameter names and their values.
The attribute should contain at least the host and port parameters that specify the
Internet Protocol dotted address or host name of the computer the debugger is
running, and the TCP port number the debugger is listening to for debug connections.
Attribute Data Type
oratext *

Example
OCIAttrSet(session,
OCI_HTYPE_SESSION,
(void *)"janedoe",
(ub4)strlen("janedoe"),
OCI_ATTR_CLIENT_IDENTIFIER,
error_handle);

OCI_ATTR_PASSWORD
Mode
WRITE
Description
Specifies a password to use for authentication.
Attribute Data Type
oratext *

A-29

Appendix A

Server Handle Attributes

OCI_ATTR_PROXY_CLIENT
Mode
WRITE
Description
Specifies the target user name for access through a proxy.
Attribute Data Type
oratext *

OCI_ATTR_PROXY_CREDENTIALS
Mode
WRITE
Description
Specifies that the credentials of the application server are to be used for proxy
authentication.
Attribute Data Type
OCISession

OCI_ATTR_PURITY
Mode
READ/WRITE
Description
An attribute of the OCIAuthInfo handle for database resident connection pooling.
Values are OCI_ATTR_PURITY_NEW, the application requires a session not tainted with
any prior session state; or OCI_ATTR_PURITY_SELF, the session can have been used
before. If the application does not specify the purity when invoking OCISessionGet(),
then the purity value OCI_ATTR_PURITY_DEFAULT is assumed. This later translates to
either OCI_ATTR_PURITY_NEW or OCI_ATTR_PURITY_SELF depending upon whether the
application logic is set up to use a new session or to reuse a pooled session.
Attribute Data Type
ub4 */ub4
OCI_ATTR_SESSION_STATE
Mode
READ/WRITE
Description
Specifies the current state of the database session. Set to OCI_SESSION_STATEFUL if the
session is required to perform a database task. If the application is no longer
dependent on the current session for subsequent database activity, set to
OCI_SESSION_STATELESS. This attribute is currently applicable only when connected to a
Database Resident Connection Pool. It should be used if the application does custom
session pooling and does not use OCISessionPool().
Attribute Data Type
ub1 */ ub1

A-30

Appendix A

Server Handle Attributes

OCI_ATTR_SHARDING_KEY
Mode
WRITE
Description
For the shard and chunk, specifies the sharding key for the connection request from
an OCI session pool or standalone connection.
The OCIShardingKey * supplied to OCIAttrSet() needs to be created with
OCIDescriptorAlloc() specifying the sharding descriptor and then using as many calls
as is needed to OCIShardingKeyColumnAdd() to create the compound sharding key. See
OCIShardingKeyColumnAdd() for more information and an example.
For custom pools, this attribute associates a sharding key to a given connection.
Attribute Data Type
OCIShardingKey *

Example
/* Allocate the super sharding key descriptor. */
OCIDescriptorAlloc(envhp,(dvoid **)&shardKey,
OCI_DTYPE_SHARDING_KEY, 0,(dvoid **)0)))
text *name = “KK”;
text *gname = “GOLD”;
int empid = 150;
/* Add all the columns of the key to form the final shard key. */
OCIShardingKeyColumnAdd(shardKey,(ub1*)&empid, sizeof(empid),
SQLT_INT, errhp, OCI_DEFAULT);
OCIShardingKeyColumnAdd(shardKey, name, strlen(name),
SQLT_CHAR, errhp, OCI_DEFAULT));
OCIShardingKey *shardKey;
OCIAttrSet(authp, OCI_HTYPE_AUTHINFO,
shardKey, sizeof(shardKey),
OCI_ATTR_SHARDING_KEY, errhp);

OCI_ATTR_SHARDING_KEY_B64
Mode
WRITE
Description
Gets the base64 representation of sharding key and super sharding key values for
diagnostic purposes.
Attribute Data Type
Oratext *

Example
char * skeyValue;
ub4
skeyValueLen;
OCIAttrGet((dvoid *)
(ub4)
(dvoid *)
(ub4 *)

OCIShardingKey,
OCI_DTYPE_SHARDING_KEY,
&skeyValue,
&skeyValueLen,

A-31

Appendix A

Server Handle Attributes

OCI_ATTR_SHARDING_KEY_B64,
(OCIError * ) errhp);

OCI_ATTR_SUPER_SHARDING_KEY
Mode
WRITE
Description
For the shard and group of chunks, specifies the super sharding key for the
connection request from an OCI session pool or standalone connection.
The OCIShardingKey * supplied to OCIAttrSet() needs to be created with
OCIDescriptorAlloc() specifying the sharding descriptor and then using as many calls
as is needed to OCIShardingKeyColumnAdd() to create the compound shard key. See
OCIShardingKeyColumnAdd() for more information and an example.
For custom pools, this attribute associates a shard group key to a given connection.
Attribute Data Type
OCIShardingKey *

Example
/* Allocate the sharding key descriptor. */
OCIDescriptorAlloc(envhp,(dvoid **)&shardGroupKey,
OCI_DTYPE_SHARDING_KEY, 0, (dvoid **)0));
/* Add the column of the key to form the final super sharding key. */
OCIShardingKeyColumnAdd(shardGroupKey, errhp, gname, strlen(gname),
SQLT_CHAR, OCI_DEFAULT));
OCIShardingKey *shardGroupKey;
OCIAttrSet(authp, OCI_HTYPE_AUTHINFO,
shardGroupKey, sizeof(shardGroupKey),
OCI_ATTR_SUPER_SHARDING_KEY, errhp));

OCI_ATTR_TRANS_PROFILE_FOREIGN
Mode
READ
Description
Specifies whether a SQL translation profile for translation of foreign SQL syntax is set
in the current session or not.
Attribute Data Type
boolean

Example
status = OCIAttrGet(authp,
OCI_HTYPE_SESSION,
(void *)&foreign_sql_syntax,
(ub4 *)NULL,
OCI_ATTR_TRANS_PROFILE_FOREIGN,
errhp);

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Appendix A

Administration Handle Attributes

OCI_ATTR_TRANSACTION_IN_PROGRESS
Mode
READ
Description
If TRUE, then the referenced session has a currently active transaction.
If FALSE, then the referenced session does not have a currently active transaction.
Attribute Data Type
boolean *

Example
{ boolean txnInProgress;
OCIAttrGet(usrhp, OCI_HTYPE_SESSION,
&txnInProgress, (ub4 *)0,
OCI_ATTR_TRANSACTION_IN_PROGRESS,
errhp);
}

OCI_ATTR_USERNAME
Mode
READ/WRITE
Description
Specifies a user name to use for authentication.
Attribute Data Type
oratext **/oratext *

A.6 Administration Handle Attributes
Lists and describes administration handle attributes.
The following attributes are used for the administration handle.
OCI_ATTR_ADMIN_PFILE
Mode
READ/WRITE
Description
Set this attribute before a call to OCIDBStartup() to specify the location of the clientside parameter file that is used to start the database. If this attribute is not set, then
the server-side parameter file is used. If the server-side parameter file does not exist,
an error is returned.
Attribute Data Type
oratext */oratext *

A-33

Appendix A

Connection Pool Handle Attributes

A.7 Connection Pool Handle Attributes
Lists and describes connection pool handle attributes.
The following attributes are used for the connection pool handle.
OCI_ATTR_CONN_TIMEOUT

Note:
Shrinkage of the pool only occurs when there is a network round-trip. If there
are no operations, then the connections remain active.

Mode
READ/WRITE
Description
Connections idle for more than this time value (in seconds) are terminated to maintain
an optimum number of open connections. This attribute can be set dynamically. If this
attribute is not set, the connections are never timed out.
Attribute Data Type
ub4 */ub4

OCI_ATTR_CONN_NOWAIT
Mode
READ/WRITE
Description
This attribute determines if retrial for a connection must be performed when all
connections in the pool are found to be busy and the number of connections has
reached the maximum.
If this attribute is set, an error is thrown when all the connections are busy and no
more connections can be opened. Otherwise, the call waits until it gets a connection.
When read, the attribute value is returned as TRUE if it has been set.
Attribute Data Type
ub1 */ub1

OCI_ATTR_CONN_BUSY_COUNT
Mode
READ
Description
Returns the number of busy connections.
Attribute Data Type
ub4 *

A-34

Appendix A

Connection Pool Handle Attributes

OCI_ATTR_CONN_OPEN_COUNT
Mode
READ
Description
Returns the number of open connections.
Attribute Data Type
ub4 *

OCI_ATTR_CONN_MIN
Mode
READ
Description
Returns the number of minimum connections.
Attribute Data Type
ub4 *

OCI_ATTR_CONN_MAX
Mode
READ
Description
Returns the number of maximum connections.
Attribute Data Type
ub4 *

OCI_ATTR_CONN_INCR
Mode
READ
Description
Returns the connection increment parameter.
Attribute Data Type
ub4 *

A.7.1 Session Pool Handle Attributes
Lists and describes session pool handle attributes.
The following attributes are used for the session pool handle.
OCI_ATTR_SPOOL_AUTH
Mode
WRITE

A-35

Appendix A

Connection Pool Handle Attributes

Description
To make pre-session creation attributes effective on the sessions being retrieved from
the session pool, this attribute can be set on the session pool handle. Currently only
the following attributes can be set on this OCIAuthInfo handle:
OCI_ATTR_DRIVER_NAME
OCI_ATTR_EDITION
OCI_ATTR_FIXUP_CALLBACK

If any other attributes are set on the OCIAuthInfo handle and the OCIAuthInfo handle is
set on the session pool handle, an error results. Moreover, the OCIAuthInfo handle
should be set on the session pool handle only before calling OCISessionPoolCreate()
with the session pool handle. Setting it after OCISessionPoolCreate() results in an
error.
Attribute Data Type
OCIAuthInfo *

OCI_ATTR_SPOOL_BUSY_COUNT
Mode
READ
Description
Returns the number of busy sessions checked out from the pool.
Attribute Data Type
ub4 *

OCI_ATTR_FOCBK
Mode
READ/WRITE
Description
On OCIAttrSet(), defines a TAF callback and context to be associated with each
session in the OCI session pool.
On OCIAttrGet(), populates the OCIFocbkStruct with the TAF callback and context
defined for the session pool.

Note:
•

This attribute is already supported for handles of type OCIServer and
OCICPool.

•

A TAF callback set on the server handle will override the callback set on
the session pool.

Attribute Data Type
OCIFocbkStruct *

OCI_ATTR_SPOOL_GETMODE
Mode
READ/WRITE

A-36

Appendix A

Connection Pool Handle Attributes

Description
This attribute determines the behavior of the session pool when all sessions in the
pool are found to be busy and the number of sessions has reached the maximum or
the pool must create new connections. Values are:
•

OCI_SPOOL_ATTRVAL_WAIT - The thread waits and blocks until a session is freed or a

new one is created. This is the default value.
•

OCI_SPOOL_ATTRVAL_TIMEDWAIT - Keep trying internally for a free session until the
time out set by OCI_ATTR_SPOOL_WAIT_TIMEOUT expires.

•

OCI_SPOOL_ATTRVAL_NOWAIT - An error is returned if there are no free connections or

if the pool must create a new connection.
•

OCI_SPOOL_ATTRVAL_FORCEGET - A new session is created even though all the

sessions are busy and the maximum number of sessions has been reached.
OCISessionGet() returns a warning. In this case, if new sessions are created that
have exceeded the maximum, OCISessionGet() returns a warning.
Note that if this value is set, it is possible that there can be an attempt to create
more sessions than can be supported by the instance of the Oracle database. In
this case, the server returns the following error:
ORA 00018 - Maximum number of sessions exceeded

In this case, the error is propagated to the session pool user.
When read, the appropriate attribute value is returned.
Attribute Data Type
ub1 */ ub1

OCI_ATTR_SPOOL_INCR
Mode
READ
Description
Returns the session increment parameter.
Attribute Data Type
ub4 *

OCI_ATTR_SPOOL_MAX
Mode
READ
Description
Returns the number of maximum sessions.
Attribute Data Type
ub4 *

OCI_ATTR_SPOOL_MAX_LIFETIME_SESSION
Mode
READ/WRITE

A-37

Appendix A

Connection Pool Handle Attributes

Description
This attribute sets the lifetime (in seconds) for all the sessions in the pool. Sessions in
the pool are terminated when they have reached their lifetime. In the case when
OCI_ATTR_SPOOL_TIMEOUT is also set, the session will be terminated if either the idle time
out happens or the max lifetime setting is exceeded.
Attribute Data Type
ub4 */ ub4
OCI_ATTR_SPOOL_MAX_USE_SESSION
Mode
WRITE
Description
Sets the maximum number of times one session can be checked out of the session
pool, after which the session is automatically destroyed. The default value is 0, which
means there is no limit. This value can also be set in the oraaccess.xml client-side
configuration file under the  section as .
Attribute Data Type
ub4

OCI_ATTR_SPOOL_MIN
Mode
READ
Description
Returns the number of minimum sessions.
Attribute Data Type
ub4 *

OCI_ATTR_SPOOL_OPEN_COUNT
Mode
READ
Description
Returns the number of open sessions.
Attribute Data Type
ub4 *

OCI_ATTR_SPOOL_STMTCACHESIZE
Mode
READ/WRITE
Description
Sets the default statement cache size to this value for each of the sessions in a
session pool. The statement cache size for a particular session in the pool can, at any
time, be overridden by using OCI_ATTR_STMTCACHESIZE on that session.

A-38

Appendix A

Transaction Handle Attributes

See Also:
Statement Caching in OCI
Attribute Data Type
ub4 */ ub4
OCI_ATTR_SPOOL_TIMEOUT
Mode
READ/WRITE
Description
The sessions idle for more than this time (in seconds) are terminated periodically to
maintain an optimum number of open sessions. This attribute can be set dynamically.
If this attribute is not set, the least recently used sessions may be timed out if and
when space in the pool is required. OCI only checks for timed out sessions when it
releases one back to the pool. See OCI_ATTR_SPOOL_MAX_LIFETIME_SESSION
for more information.
Attribute Data Type
ub4 */ ub4

OCI_ATTR_SPOOL_WAIT_TIMEOUT
Mode
READ/WRITE
Description
This is the time out (in milliseconds) applied for the OCISessionGet() call while waiting
for a free session, when the OCI_ATTR_SPOOL_GETMODE property is set to
OCI_SPOOL_ATTRVAL_TIMEDWAIT. This is also applicable in case of sharding, where the
OCISessionGet() call waits for a free session to an instance with writable chunks.
Attribute Data Type
ub4 */ ub4

OCI_ATTR_SPOOL_MAX_PER_SHARD
Mode
READ/WRITE
Description
Sets the maximum number of sessions per shard. This attribute is set to ensure that
the pool is balanced towards each shard.
Attribute Data Type
ub4 *

A.8 Transaction Handle Attributes
Lists and describes transaction handle attributes.
The following attributes are used for the transaction handle.

A-39

Appendix A

Statement Handle Attributes

OCI_ATTR_TRANS_NAME
Mode
READ/WRITE
Description
Can be used to establish or read a text string that identifies a transaction. This is an
alternative to using the XID to identify the transaction. The oratext string can be up to
64 bytes long.
Attribute Data Type
oratext ** (READ) / oratext * (WRITE)
OCI_ATTR_TRANS_TIMEOUT
Mode
READ/WRITE
Description
Can set or read a timeout interval value used at prepare time.
Attribute Data Type
ub4 * (READ) / ub4 (WRITE)
OCI_ATTR_XID
Mode
READ/WRITE
Description
Can set or read an XID that identifies a transaction.
Attribute Data Type
XID ** (READ) / XID * (WRITE)

A.9 Statement Handle Attributes
Lists and describes statement handle attributes.
The following attributes are used for the statement handle.
OCI_ATTR_BIND_COUNT
Mode
READ
Description
Returns the number of bind positions on the statement handle.
Attribute Data Type
ub4 *

A-40

Appendix A

Statement Handle Attributes

Example
OCIHandleAlloc(env,(void **) &pStatement, OCI_HTYPE_STMT, (size_t)0, (void **)0);
OCIStmtPrepare (pStatement, err, pszQuery, (ub4)strlen(pszQuery),
(ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
OCIAttrGet(pStatement, OCI_HTYPE_STMT, &iNbParameters, NULL, OCI_ATTR_BIND_COUNT,
err);

OCI_ATTR_CHNF_REGHANDLE
Mode
WRITE
Description
When this attribute is set to the appropriate subscription handle, execution of the
query also creates the registration of the query for continuous query notification.

See Also:
Continuous Query Notification Attributes
Attribute Data Type
OCISubscription *

Example
/* Associate the statement with the subscription handle */
OCIAttrSet (stmthp, OCI_HTYPE_STMT, subscrhp, 0,
OCI_ATTR_CHNF_REGHANDLE, errhp);

OCI_ATTR_CQ_QUERYID
Mode
READ
Description
Obtains the query ID of a registered query after registration is made by the call to
OCIStmtExecute().
Attribute Data Type
ub8 *

OCI_ATTR_CURRENT_POSITION
Mode
READ
Description
Indicates the current position in the result set. This attribute can only be retrieved. It
cannot be set.
Attribute Data Type
ub4 *

A-41

Appendix A

Statement Handle Attributes

OCI_ATTR_ENV
Mode
READ
Description
Returns the environment context associated with the statement.
Attribute Data Type
OCIEnv **

OCI_ATTR_FETCH_ROWID
Mode
READ/WRITE
Description
Specifies that the ROWIDs are fetched after doing a define at position 0, and a
SELECT...FOR UPDATE statement.

See Also:
Implicit Fetching of ROWIDs
Attribute Data Type
boolean */boolean
OCI_ATTR_IMPLICIT_RESULT_COUNT
Mode
READ
Description
Returns the total number of implicit results available on the top-level OCI statement
handle.
Attribute Data Type
ub4 *

OCI_ATTR_NUM_DML_ERRORS
Mode
READ
Description
Returns the number of errors in the DML operation.
Attribute Data Type
ub4 *

A-42

Appendix A

Statement Handle Attributes

OCI_ATTR_PARAM_COUNT
Mode
READ
Description
Gets the number of columns in the select-list for the statement associated with the
statement handle.
Attribute Data Type
ub4 *

Example
...
int i = 0;
ub4 parmcnt = 0;
ub2 type = 0;
OCIParam *colhd = (OCIParam *) 0;

/* column handle */

/* Describe of a select-list */
OraText *sqlstmt = (OraText *)"SELECT * FROM employees WHERE employee_id = 100";
checkerr(errhp, OCIStmtPrepare(stmthp, errhp, (OraText *)sqlstmt,
(ub4)strlen((char *)sqlstmt),
(ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT));
checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, 1, 0,
(OCISnapshot *)0, (OCISnapshot *)0, OCI_DESCRIBE_ONLY));
/* Get the number of columns in the select list */
checkerr(errhp, OCIAttrGet((void *)stmthp, OCI_HTYPE_STMT, (void *)&parmcnt,
(ub4 *)0, OCI_ATTR_PARAM_COUNT, errhp));
/* Go through the column list and retrieve the data type of each column. You
start from pos = 1 */
for (i = 1; i <= parmcnt; i++)
{
/* Get parameter for column i */
checkerr(errhp, OCIParamGet((void *)stmthp, OCI_HTYPE_STMT, errhp,
(void **)&colhd, i));
/* Get data-type of column i */
type = 0;
checkerr(errhp, OCIAttrGet((void *)colhd, OCI_DTYPE_PARAM,
(void *)&type, (ub4 *)0, OCI_ATTR_DATA_TYPE, errhp));
}
...

OCI_ATTR_PARSE_ERROR_OFFSET
Mode
READ
Description
Returns the parse error offset for a statement.

A-43

Appendix A

Statement Handle Attributes

Attribute Data Type
ub2 *

OCI_ATTR_PREFETCH_MEMORY
Mode
WRITE
Description
Sets the memory level for top-level rows to be prefetched. Rows up to the specified
top-level row count are fetched if the memory level occupies no more than the
specified memory usage limit. The default value is 0, which means that memory size
is not included in computing the number of rows to prefetch.
Attribute Data Type
ub4 *

OCI_ATTR_PREFETCH_ROWS
Mode
WRITE
Description
Sets the number of top-level rows to be prefetched. The default value is 1 row.
Attribute Data Type
ub4 *

OCI_ATTR_ROW_COUNT
Mode
READ
Description
Returns the number of rows processed so far after SELECT statements. For INSERT,
UPDATE, and DELETE statements, it is the number of rows processed by the most recent
statement. The default value is 1.
For nonscrollable cursors, OCI_ATTR_ROW_COUNT is the total number of rows fetched into
user buffers with the OCIStmtFetch2() calls issued since this statement handle was
executed. Because they are forward sequential only, this also represents the highest
row number seen by the application.
For scrollable cursors, OCI_ATTR_ROW_COUNT represents the maximum (absolute) row
number fetched into the user buffers. Because the application can arbitrarily position
the fetches, this need not be the total number of rows fetched into the user's buffers
since the (scrollable) statement was executed.
Beginning with Oracle Database Release 12.1, using the attribute
OCI_ATTR_UB8_ROW_COUNT is preferred to using the attribute OCI_ATTR_ROW_COUNT if row
count values can exceed the value of UB4MAXVAL for an OCI application. If the row
count exceeds the value of UB4MAXVAL and the application uses the attribute
OCI_ATTR_ROW_COUNT, a call using OCIAttrGet() will return an error.
Attribute Data Type
ub4 *

A-44

Appendix A

Statement Handle Attributes

OCI_ATTR_DML_ROW_COUNT_ARRAY
Mode
READ
Description
Returns an array of row counts affected by each iteration of an array DML statement.
The row count for iteration i can be obtained by looking up array[i-1].
Without OCI_BATCH_ERRORS mode, OCIStmtExecute() stops execution with the first
erroneous iteration. In such a scenario, the array returned by the
OCI_ATTR_DML_ROW_COUNT_ARRAY attribute only contains valid row counts up to and
including the last successful iteration. When OCI_RETURN_ROW_COUNT_ARRAY mode is used
in conjunction with OCI_BATCH_ERRORS mode, the returned row-count array contains the
actual number of rows affected per successful iteration and 0 for iterations that
resulted in errors.
This attribute works only when the statement is executed in mode
OCI_RETURN_ROW_COUNT_ARRAY at the time of using OCIStmtExecute().
Use this attribute only after an array DML operation and while using
OCI_RETURN_ROW_COUNT_ARRAY mode in OCIStmtExecute().
Any attempt to query this attribute after any other operation (other than an array DML)
or without passing this mode will result in an OCI_ERROR (ORA-24349).
Attribute Data Type
ub8 *

Example
int deptarray[]={10,20,30};
int iters = 3;
ub8 *rowcounts;
ub4 rowCountArraySize;
/*Statement prepare */
text *updatesal = (text *)"UPDATE EMP set sal = sal+100 where deptno = :dept"
OCIStmtPrepare2 ((OCISvcCtx *)svchp,(OCIStmt **)&stmthp,
(OCIError *)errhp, (text *)updatesal, (ub4)sizeof(updatesal)-1,
(oratext *)NULL, (ub4) 0, (ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT);
/*Array bind*/
OCIBindByPos (stmthp, &bndhp, errhp, 1, deptarray, sizeof(deptarray[0]),
SQLT_INT, (ub2 *) 0, (ub2 *) 0, (ub4) 0, (ub4) 0, (ub4 *) 0,
(ub4) OCI_DEFAULT);
/* Pass new MODE for Array DML rowcounts; also, if an error occurred for any
iteration and you want to get the number of rows updated for the rest of the
iterations.*/
OCIStmtExecute(svchp, stmthp, errhp, iters, (ub4) 0, 0, 0, OCI_BATCH_ERRORS |
OCI_RETURN_ROWCOUNT_ARRAY);
OCIAttrGet (stmthp, (ub4) OCI_HTYPE_STMT,
(ub8 *)&rowcounts, &rowCountArraySize,
OCI_ATTR_DML_ROW_COUNT_ARRAY, errhp);

OCI_ATTR_ROWID
Mode
READ
Description
Returns the ROWID descriptor allocated with OCIDescriptorAlloc().

A-45

Appendix A

Statement Handle Attributes

See Also:
Positioned Updates and Deletes and ROWID Descriptor
Attribute Data Type
OCIRowid *
OCI_ATTR_ROWS_FETCHED
Mode
READ
Description
Indicates the number of rows that were successfully fetched into the user's buffers in
the last fetch or execute with nonzero iterations. It can be used for both scrollable and
nonscrollable statement handles.
Attribute Data Type
ub4 *

Example
ub4 rows;
ub4 sizep = sizeof(ub4);
OCIAttrGet((void *) stmhp, (ub4) OCI_HTYPE_STMT,
(void *)& rows, (ub4 *) &sizep, (ub4)OCI_ATTR_ROWS_FETCHED,
errhp);

OCI_ATTR_SQL_ID
Mode
READ
Dexcription
Gets the SQL_ID for a specific SQL statement from the server and makes it available
on the client in a statement handle.
Attribute Data Type
ub4 *

Example
In an OCIStmtPrepare2(), specify OCI_PREP2_GET_SQL_ID as the mode. This
OCI_PREP2_GET_SQL_ID mode should be ORed with any other mode. For example:
OCIStmtPrepare2((dvoid *)ctxptr->svchp, &stmthp,
(dvoid *)ctxptr->errhp,
insStmt, sizeof(insStmt),
(const oratext *)0, (ub4)0,
OCI_NTV_SYNTAX,
OCI_DEFAULT | OCI_PREP2_GET_SQL_ID);

You can do a bind or define operation and then execute on the statement.
The following code example shows how to obtain the SQL_ID.

A-46

Appendix A

Statement Handle Attributes

ub4
oratext

sqlidLen;
*sqlid;
OCIAttrGet(stmthp, OCI_HTYPE_STMT,
&sqlid, (ub4 *)&sqlidLen,
OCI_ATTR_SQL_ID,
ctxptr->errhp);

OCI_ATTR_SQLFNCODE
Mode
READ
Description
Returns the function code of the SQL command associated with the statement.
Attribute Data Type
ub2 *

Notes
Table A-1 lists the SQL command codes.
Table A-1

Function Code of the SQL Command Associated with the SQL Statement

Func SQL Statement
tion
Code

Func SQL Statement
tion
Code

Func SQL Statement
tion
Code

01

CREATE TABLE

43

DROP EXTERNAL
DATABASE

85

TRUNCATE TABLE

02

SET ROLE

44

CREATE DATABASE

86

TRUNCATE CLUSTER

03

INSERT

45

ALTER DATABASE

87

CREATE BITMAPFILE

04

SELECT

46

CREATE ROLLBACK
SEGMENT

88

ALTER VIEW

05

UPDATE

47

ALTER ROLLBACK
SEGMENT

89

DROP BITMAPFILE

06

DROP ROLE

48

DROP ROLLBACK
SEGMENT

90

SET CONSTRAINTS

07

DROP VIEW

49

CREATE TABLESPACE

91

CREATE FUNCTION

08

DROP TABLE

50

ALTER TABLESPACE

92

ALTER FUNCTION

09

DELETE

51

DROP TABLESPACE

93

DROP FUNCTION

10

CREATE VIEW

52

ALTER SESSION

94

CREATE PACKAGE

11

DROP USER

53

ALTER USER

95

ALTER PACKAGE

12

CREATE ROLE

54

COMMIT (WORK)

96

DROP PACKAGE

13

CREATE SEQUENCE

55

ROLLBACK

97

CREATE PACKAGE BODY

14

ALTER SEQUENCE

56

SAVEPOINT

98

ALTER PACKAGE BODY

15

(NOT USED)

57

CREATE CONTROL FILE

99

DROP PACKAGE BODY

16

DROP SEQUENCE

58

ALTER TRACING

157

CREATE DIRECTORY

17

CREATE SCHEMA

59

CREATE TRIGGER

158

DROP DIRECTORY

18

CREATE CLUSTER

60

ALTER TRIGGER

159

CREATE LIBRARY

19

CREATE USER

61

DROP TRIGGER

160

CREATE JAVA

20

CREATE INDEX

62

ANALYZE TABLE

161

ALTER JAVA

A-47

Appendix A

Statement Handle Attributes

Table A-1

(Cont.) Function Code of the SQL Command Associated with the SQL Statement

Func SQL Statement
tion
Code

Func SQL Statement
tion
Code

Func SQL Statement
tion
Code

21

DROP INDEX

63

ANALYZE INDEX

162

DROP JAVA

22

DROP CLUSTER

64

ANALYZE CLUSTER

163

CREATE OPERATOR

23

VALIDATE INDEX

65

CREATE PROFILE

164

CREATE INDEXTYPE

24

CREATE PROCEDURE

66

DROP PROFILE

165

DROP INDEXTYPE

25

ALTER PROCEDURE

67

ALTER PROFILE

166

ALTER INDEXTYPE

26

ALTER TABLE

68

DROP PROCEDURE

167

DROP OPERATOR

27

EXPLAIN

69

(NOT USED)

168

ASSOCIATE STATISTICS

28

GRANT

70

ALTER RESOURCE COST

169

DISASSOCIATE
STATISTICS

29

REVOKE

71

CREATE SNAPSHOT LOG

170

CALL METHOD

30

CREATE SYNONYM

72

ALTER SNAPSHOT LOG

171

CREATE SUMMARY

31

DROP SYNONYM

73

DROP SNAPSHOT LOG

172

ALTER SUMMARY

32

ALTER SYSTEM SWITCH
LOG

74

CREATE SNAPSHOT

173

DROP SUMMARY

33

SET TRANSACTION

75

ALTER SNAPSHOT

174

CREATE DIMENSION

34

PL/SQL EXECUTE

76

DROP SNAPSHOT

175

ALTER DIMENSION

35

LOCK

77

CREATE TYPE

176

DROP DIMENSION

36

NOOP

78

DROP TYPE

177

CREATE CONTEXT

37

RENAME

79

ALTER ROLE

178

DROP CONTEXT

38

COMMENT

80

ALTER TYPE

179

ALTER OUTLINE

39

AUDIT

81

CREATE TYPE BODY

180

CREATE OUTLINE

40

NO AUDIT

82

ALTER TYPE BODY

181

DROP OUTLINE

41

ALTER INDEX

83

DROP TYPE BODY

182

UPDATE INDEXES

42

CREATE EXTERNAL
DATABASE

84

DROP LIBRARY

183

ALTER OPERATOR

OCI_ATTR_STATEMENT
Mode
READ
Description
Returns the text of the SQL statement prepared in a statement handle. In UTF-16
mode, the returned statement is in UTF-16 encoding. The length is always in bytes.
Attribute Data Type
oratext *

A-48

Appendix A

Statement Handle Attributes

OCI_ATTR_STMTCACHE_CBKCTX
Mode
READ/WRITE
Description
Used to get and set the application's opaque context on the statement handle. This
context can be of any type that the application defines. It is primarily used for
encompassing the bind and define buffer addresses.
Attribute Data Type
void *

OCI_ATTR_STMT_IS_RETURNING
Mode
READ
Description
Determines whether the given SQL Statement has a RETURNING INTO clause.
Attribute Data Type
ub1

Example
returning_into_clause = OCIAttrGet ( stmthp, OCI_HTYPE_STMT, (ub1*)&isReturning,
NULL, OCI_ATTR_STMT_IS_RETURNING, errhp);

OCI_ATTR_STMT_STATE
Mode
READ
Description
Returns the fetch state of that statement. This attribute can be used by the caller to
determine if the session can be used in another service context or if it is still needed in
the current set of data access calls. Basically, if you are in the middle of a fetchexecute cycle, then you do not want to release the session handle for another
statement execution. Valid values are:
•

OCI_STMT_STATE_INITIALIZED

•

OCI_STMT_STATE_EXECUTED

•

OCI_STMT_STATE_END_OF_FETCH

Attribute Data Type
ub4 *

OCI_ATTR_STMT_TYPE
Mode
READ
Description
The type of statement associated with the handle. Valid values are:

A-49

Appendix A

Bind Handle Attributes

•

OCI_STMT_SELECT

•

OCI_STMT_UPDATE

•

OCI_STMT_DELETE

•

OCI_STMT_INSERT

•

OCI_STMT_CREATE

•

OCI_STMT_DROP

•

OCI_STMT_ALTER

•

OCI_STMT_BEGIN (PL/SQL statement)

•

OCI_STMT_DECLARE (PL/SQL statement)

•

OCI_STMT_CALL (PL/SQL statement)

•

OCI_STMT_MERGE (PL/SQL statement)

Attribute Data Type
ub2 *

OCI_ATTR_UB8_ROW_COUNT (Recommended over OCI_ATTR_ROW_COUNT)
Mode
READ
Description
For SELECT statements, returns the cumulative number of rows fetched from a result
set. For INSERT, UPDATE, and DELETE statements, this attribute returns the number of
rows processed by the statement. The default value is 1.
For non-scrollable cursors, OCI_ATTR_UB8_ROW_COUNT is the total number of rows fetched
into user buffers with the OCIStmtFrtch() or OCIStmtFetch2() calls issued since this
statement handle was executed. For these non-scrollable cursors, this also
represents the highest row number seen by the application.
If using the attribute OCI_ATTR_ROW_COUNT and the row count returned is larger than
UB4MAXVAL, then one or both of the following errors may be returned:
ORA-03148. OCI_ATTR_ROW_COUNT cannot see row counts larger than UB4MAXVAL

Attribute Data Type
ub8 *

A.10 Bind Handle Attributes
Lists and describes bind handle attributes.
The following attributes are used for the bind handle.
OCI_ATTR_CHAR_COUNT
Mode
WRITE
Description
Sets the number of characters in character type data.

A-50

Appendix A

Bind Handle Attributes

See Also:
Buffer Expansion During OCI Binding
Attribute Data Type
ub4 *

OCI_ATTR_CHARSET_FORM
Mode
READ/WRITE
Description
Character set form of the bind handle. The default form is SQLCS_IMPLICIT. Setting this
attribute causes the bind handle to use the database or national character set on the
client side. Set this attribute to SQLCS_NCHAR for the national character set or
SQLCS_IMPLICIT for the database character set.
Attribute Data Type
ub1 *

OCI_ATTR_CHARSET_ID
Mode
READ/WRITE
Description
Character set ID of the bind handle. If the character set of the input data is UTF-16,
the user must set the character set ID to OCI_UTF16ID (replaces the deprecated
OCI_UC2SID, which is retained for backward compatibility). The bind value buffer is
assumed to be a utext buffer, so length semantics for input length pointers and return
values changes to character semantics (number of utexts). However, the size of the
bind value buffer in the preceding OCIBind call must be stated in bytes.
If OCI_ATTR_CHARSET_FORM is set, then OCI_ATTR_CHARSET_ID should be set only afterward.
Setting OCI_ATTR_CHARSET_ID before setting OCI_ATTR_CHARSET_FORM causes unexpected
results.

See Also:
Character Conversion in OCI Binding and Defining
Attribute Data Type
ub2 *

OCI_ATTR_COLLATION_ID
Mode
READ/WRITE

A-51

Appendix A

Bind Handle Attributes

Description
Sets the derived collation of a placeholder expression corresponding to this bind
handle in a SQL statement. The attribute is relevant only for bind variables with
character data types.
You can set the OCI_ATTR_COLLATION_ID attribute on a bind variable handle to any of
the supported collation IDs. Collation IDs of both named collations and pseudocollations are allowed. The attribute value is passed to the server with other bind
information and the corresponding bind variable reference, formally known as SQL
placeholder expression, assumes the provided collation at the coercibility level 0. If
the attribute value is OCI_COLLATION_NONE (the default value), the collation of the bind
variable is USING_NLS_COMP at the coercibility level 4.
OCI does not check whether the collation is valid for a given data type of a bind
variable. If OCI_ATTR_COLLATION_ID is set for a non-character data type variable, it is
ignored by the server.
Collation of bind variables is currently ignored in PL/SQL expressions. For forward
compatibility reasons, the OCI_ATTR_COLLATION_ID attribute should not be set for bind
variables passed to an anonymous PL/SQL block, unless the variables are referenced
exclusively in SQL statements.

Note:
You can use the SQL built-in functions NLS_COLLATION_ID and
NLS_COLLATION_NAME to map between values of the attribute, which are
collation IDs, and collation names used in SQL syntax.

See Also:
•

Column Attributes

•

Oracle Database Globalization Support Guide for information on how
this set collation influences query processing

Attribute Data Type
ub4 *

OCI_ATTR_MAXCHAR_SIZE
Mode
WRITE
Description
Sets the number of characters that an application reserves on the server to store the
data being bound.

See Also:
About Using the OCI_ATTR_MAXCHAR_SIZE Attribute

A-52

Appendix A

Bind Handle Attributes

Attribute Data Type
sb4 *

OCI_ATTR_MAXDATA_SIZE
Mode
READ/WRITE
Description
Sets the maximum number of bytes allowed in the buffer on the server side to
accommodate client-side bind data after character set conversions.

See Also:
About Using the OCI_ATTR_MAXDATA_SIZE Attribute
Attribute Data Type
sb4 *

OCI_ATTR_PDPRC
Mode
WRITE
Description
Specifies packed decimal precision. For SQLT_PDN values, the precision should be
equal to 2*(value_sz-1). For SQLT_SLS values, the precision should be equal to
(value_sz-1).
After a bind or define, this value is initialized to zero. The OCI_ATTR_PDPRC attribute
should be set first, followed by OCI_ATTR_PDSCL. If either of these values must be
changed, first perform a rebind/redefine operation, and then reset the two attributes in
order.
Attribute Data Type
ub2 *

OCI_ATTR_PDSCL
Mode
WRITE
Description
Specifies the scale for packed decimal values.
After a bind or define, this value is initialized to zero. The OCI_ATTR_PDPRC attribute
should be set first, followed by OCI_ATTR_PDSCL. If either of these values must be
changed, first perform a rebind/redefine operation, and then reset the two attributes in
order.
Attribute Data Type
sb2 *

A-53

Appendix A

Define Handle Attributes

OCI_ATTR_ROWS_RETURNED
Mode
READ
Description
This attribute returns the number of rows that will be returned in the current iteration
when you are in the OUT callback function for binding a DML statement with a
RETURNING clause.
Attribute Data Type
ub4 *

A.11 Define Handle Attributes
Lists and describes define handle attributes.
The following attributes are used for the define handle.
OCI_ATTR_CHAR_COUNT
Mode
WRITE
Description
This attribute is deprecated.
Sets the number of characters in character type data. This specifies the number of
characters desired in the define buffer. The define buffer length as specified in the
define call must be greater than number of characters.
Attribute Data Type
ub4 *

OCI_ATTR_CHARSET_FORM
Mode
READ/WRITE
Description
The character set form of the define handle. The default form is SQLCS_IMPLICIT.
Setting this attribute causes the define handle to use the database or national
character set on the client side. Set this attribute to SQLCS_NCHAR for the national
character set or SQLCS_IMPLICIT for the database character set.
Attribute Data Type
ub1 *

OCI_ATTR_CHARSET_ID
Mode
READ/WRITE
Description
The character set ID of the define handle. If the character set of the output data
should be UTF-16, the user must set the character set IDOTT to OCI_UTF16ID. The

A-54

Appendix A

Define Handle Attributes

define value buffer is assumed to be a utext buffer, so length semantics for indicators
and return values changes to character semantics (number of utexts). However, the
size of the define value buffer in the preceding OCIDefine call must be stated in bytes.
If OCI_ATTR_CHARSET_FORM is set, then OCI_ATTR_CHARSET_ID should be set only afterward.
Setting OCI_ATTR_CHARSET_ID before setting OCI_ATTR_CHARSET_FORM causes unexpected
results.

See Also:
Character Conversion in OCI Binding and Defining
Attribute Data Type
ub2 *

OCI_ATTR_LOBPREFETCH_LENGTH
Mode
READ/WRITE
Description
Specifies if the LOB length and the chunk size for the LOB locators should be
prefetched along with the descriptor if the column is a LOB column. Setting it to TRUE
will enable the prefetching and this attribute setting is also required for prefetching the
LOB data using the attribute OCI_ATTR_LOBPREFETCH_SIZE.
Attribute Data Type
boolean */boolean

OCI_ATTR_LOBPREFETCH_SIZE
Mode
READ/WRITE
Description
Overrides the default cache buffer size for the LOB locators to be fetched from a
particular column along with the descriptor. This requires the attribute
OCI_ATTR_LOBPREFETCH_LENGTH to be set to TRUE.
Attribute Data Type
ub4 */ub4

OCI_ATTR_MAXCHAR_SIZE
Mode
WRITE
Description
Specifies the maximum number of characters that the client application allows in the
define buffer.

A-55

Appendix A

Describe Handle Attributes

See Also:
About Using the OCI_ATTR_MAXCHAR_SIZE Attribute
Attribute Data Type
sb4 *

OCI_ATTR_PDPRC
Mode
WRITE
Description
Specifies packed decimal precision. For SQLT_PDN values, the precision should be
equal to 2*(value_sz-1). For SQLT_SLS values, the precision should be equal to
(value_sz-1).
After a bind or define, this value is initialized to zero. The OCI_ATTR_PDPRC attribute
should be set first, followed by OCI_ATTR_PDSCL. If either of these values must be
changed, first perform a rebind/redefine operation, and then reset the two attributes in
order.
Attribute Data Type
ub2 *

OCI_ATTR_PDSCL
Mode
WRITE
Description
Specifies the scale for packed decimal values.
After a bind or define, this value is initialized to zero. The OCI_ATTR_PDPRC attribute
should be set first, followed by OCI_ATTR_PDSCL. If either of these values must be
changed, first perform a rebind/redefine operation, and then reset the two attributes in
order.
Attribute Data Type
sb2 *

A.12 Describe Handle Attributes
Lists and describes describe handle attributes.
The following attributes are used for the describe handle.
OCI_ATTR_PARAM
Mode
READ
Description
Points to the root of the description. Used for subsequent calls to OCIAttrGet() and
OCIParamGet().

A-56

Appendix A

Describe Handle Attributes

Attribute Data Type
ub4 *

OCI_ATTR_PARAM_COUNT
Mode
READ
Description
Returns the number of parameters in the describe handle. When the describe handle
is a description of the select list, this refers to the number of columns in the select list.
Attribute Data Type
ub4 *

OCI_ATTR_SHOW_INVISIBLE_COLUMNS
Mode
WRITE
Description
This attribute requests OCIDescribeAny() to also get the metadata for invisible
columns. You can use OCIAttrGet() to determine whether a column is invisible or not.
Attribute Data Type
boolean *

Example
boolean showInvisibleCols = TRUE;
ub1 colInvisible[MAX_COLS];
OCIAttrSet(descHandle, OCI_HTYPE_DESCRIBE, &showInvisibleCols, 0,
OCI_ATTR_SHOW_INVISIBLE_COLUMNS, errHandle);
if (rc = OCIDescribeAny(svcHandle, errHandle, (dvoid*)table,
strlen(table), OCI_OTYPE_NAME, 1,
OCI_PTYPE_TABLE, descHandle))
{
OCIHandleFree(descHandle, OCI_HTYPE_DESCRIBE);
return OCI_ERROR;
}
/* Get the number of columns. */
OCIAttrGet(parHandle, OCI_DTYPE_PARAM, &nCols, 0,
OCI_ATTR_NUM_COLS, errHandle);
/* Get the column list. */
OCIAttrGet(parHandle, OCI_DTYPE_PARAM, &lstHandle, 0,
OCI_ATTR_LIST_COLUMNS, errHandle);
/* Loop through the columns. */
for (i = 1; i <= nCols; i++)
{
OCIParamGet(lstHandle, OCI_DTYPE_PARAM, errHandle,
(dvoid*)&colHandle, i);
OCIAttrGet(colHandle, OCI_DTYPE_PARAM, &colName[i-1], &len,
OCI_ATTR_NAME, errHandle);

A-57

Appendix A

Parameter Descriptor Attributes

OCIAttrGet(colHandle, OCI_DTYPE_PARAM, &(colType[i-1]), 0,
OCI_ATTR_DATA_TYPE, errHandle);
OCIAttrGet(colHandle, OCI_DTYPE_PARAM, &colInvisible[i-1], 0,
OCI_ATTR_SHOW_INVISIBLE_COLUMNS, errHandle);
if (colInvisible & OCI_ATTR_SHOW_INVISIBLE_COLUMNS)
printf("Column is invisible\n");
}

A.13 Parameter Descriptor Attributes
Lists and describes parameter descriptor attributes.
The following attributes are used for the parameter descriptor.

See Also:
Describing Schema Metadata for a detailed list of parameter descriptor
attributes.

A.14 Shard Instance Descriptor Attributes
Lists and describes shard instance descriptor attributes.
This descriptor is returned by OCIShardInstancesGet() used only by custom pools,
which essentially contains the instance name where the data matching the provided
sharding key resides, and an indication if that shard is writable on that instance.
The following attributes are used for the shard instance descriptor.
OCI_ATTR_INSTNAME
Mode
READ
Description
This attribute can be used to find the shard instance name out of a shard instance
descriptor that is filed by an OCIShardInstancesGet() call. This attribute can also be
used on the service context to return the shard instance name for a given connection.
When called as an event handle attribute, OCIAttrGet() retrieves the name of the
instance that has been affected by this event. This is also a server handle attribute.
Attribute Data Type
oratext **

Example
OCIAttrGet(shardInstance,
(ub4) OCI_DTYPE_SHARD_INST,(dvoid *)&iName, (ub4 *)&iNameLen,
OCI_ATTR_INSTNAME, (OCIError *)errhp);

A-58

Appendix A

SODA Document Handle Attributes

OCI_ATTR_SHARD_HAS_WRITABLECHUNK
Mode
READ
Description
Returns TRUE if the shard instance has writable chunks. For custom pool
implementations, this helps the pool to determine if a connection to that particular
shard instance can be dispensed. If the application can work with read only shards
instead of writable chunks, the pool can dispense it; otherwise, it can implement a
retrial logic to try OCIShardInstancesGet() until it returns shard instance information
having writable chunks. This feature is helpful during chunk migrations.
Attribute Data Type
boolean *

A.15 SODA Document Handle Attributes
The OCISodaDoc document handle has the following attributes. The key, last-modified
time stamp, creation time stamp, version, content, and media type attributes represent
document components. JSON charset ID is a read-only character set ID set by SODA.
Detect JSON Encoding is a flag for working with Unicode encoding JSON content.
The following attributes are document components:
•

Key — OCI_ATTR_SODA_KEY

•

Last-modified time stamp — OCI_ATTR_SODA_LASTMOD_TIMESTAMP

•

Creation time stamp — OCI_ATTR_SODA_CREATE_TIMESTAMP

•

Version — OCI_ATTR_SODA_VERSION

•

Content — OCI_ATTR_SODA_CONTENT

•

Media type ("application/json" for JSON documents) — OCI_ATTR_SODA_MEDIA_TYPE

The following attributes are not document components, but instead used to describe
other characteristics of the document:
•

JSON character set ID — OCI_ATTR_SODA_JSON_CHARSET_ID

•

Detect JSON encoding — OCI_ATTR_SODA_DETECT_JSON_ENC

OCI_ATTR_SODA_KEY
Mode
READ/WRITE
Description
The unique key for the document.
Attribute Data Type
oratext *

A-59

Appendix A

SODA Document Handle Attributes

OCI_ATTR_SODA_LASTMOD_TIMESTAMP
Mode
READ
Description
The last-modified time stamp for the document in ISO format. The value is NULL if the
metadata of the collection does not support it.
Attribute Data Type
oratext *

OCI_ATTR_SODA_CREATE_TIMESTAMP
Mode
READ
Description
The creation time stamp for the document in ISO format. The value is NULL if the
metadata of the collection does not support it.
Attribute Data Type
oratext *

OCI_ATTR_SODA_VERSION
Mode
READ
Description
The document version. The value is NULL if the metadata of the collection does not
support it.
Attribute Data Type
oratext *

OCI_ATTR_SODA_CONTENT
Mode
READ/WRITE
Description
The document content. Note that for OCISodaInsertAndGet(),
OCISodaInsertAndGetWithCtnt(), and OCISodaReplOneAndGetWithKey(), these functions
return the handle to the result document containing all components except the
content, so this attribute is not needed for these calls.
Attribute Data Type
oratext *

OCI_ATTR_SODA_JSON_CHARSET_ID
Mode
READ

A-60

Appendix A

SODA Collection Handle Attributes

Description
The character set ID of the document's content. This could potentially be different
from the local (client-side) character set ID.
Attribute Data Type
ub2

OCI_ATTR_SODA_DETECT_JSON_ENC
Mode
READ/WRITE
Description
Returns TRUE if the document is in detect encoding mode.
Attribute Data Type
boolean

OCI_ATTR_SODA_MEDIA_TYPE
Mode
READ/WRITE
Description
The media type for the document.
Attribute Data Type
oratext *

A.16 SODA Collection Handle Attributes
Lists and describes the OCI SODA collection handle attributes.
Collection metadata is composed of multiple components. OCI_ATTR_SODA_DESCRIPTOR is
a special case. When you pass OCI_ATTR_SODA_DESCRIPTOR to OCIAttrGet(), you get
metadata for the collection in one chunk, in JSON form. In addition,
OCI_ATTR_SODA_COLL_NAME, the collection name, is not part of collection metadata (it is
not a collection metadata component). It is stored separately in SODA, so it is also a
special case. If you use OCI_ATTR_SODA_DESCRIPTOR to fetch collection metadata in
JSON, the collection name is not included.
The rest of these attributes fetch individual metadata components. They are provided
for convenience (alternatively, you could get collection metadata using
OCI_ATTR_SODA_DESCRIPTOR. That metadata contains all of the components, but it is in
JSON form, so your application might need to parse the JSON to retrieve values of
specific components). All of these attributes are READ only and allow you to examine
the metadata for your existing collection.

A-61

Appendix A

SODA Collection Handle Attributes

See Also:
https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdi/
index.html for reference information about these SODA collection metadata
components. All the metadata components that correspond to these
collection handle attributes (except for OCI_ATTR_SODA_DESCRIPTOR and
OCI_ATTR_SODA_COLL_NAME), are described in this chapter.

The following is a list of all collection attributes followed by descriptions of each.
•

Collection Name — OCI_ATTR_SODA_COLL_NAME

•

Descriptor — OCI_ATTR_SODA_DESCRIPTOR

•

Schema — OCI_ATTR_SODA_SCHEMA

•

Table Name — OCI_ATTR_SODA_TABLE_NAME

•

View Name — OCI_ATTR_SODA_VIEW_NAME

•

Key Column Name — OCI_ATTR_SODA_KEY_COL_NAME

•

Key Column SQL Type — OCI_ATTR_SODA_KEY_SQL_TYPE

•

Key Column Max Length — OCI_ATTR_SODA_KEY_MAX_LEN

•

Key Column Assignment Method — OCI_ATTR_SODA_KEY_ASSIGN_METHOD

•

Key Column Sequence Name — OCI_ATTR_SODA_KEY_SEQ_NAME

•

Content Column Name — OCI_ATTR_SODA_CTNT_COL_NAME

•

Content Column SQL Type — OCI_ATTR_SODA_CTNT_SQL_TYPE

•

Content Column Max Length — OCI_ATTR_SODA_CTNT_MAX_LEN

•

Content Column JSON Validation — OCI_ATTR_SODA_CTNT_VALIDATION

•

Content Column SecureFiles LOB Compression — OCI_ATTR_SODA_CTNT_COMPRESS

•

Content Column SecureFiles LOB Cache — OCI_ATTR_SODA_CTNT_CACHE

•

Content Column SecureFiles LOB Encryption — OCI_ATTR_SODA_CTNT_ENCRYPT

•

Version Column Name — OCI_ATTR_SODA_VERSION_COL_NAME

•

Version Generation Method — OCI_ATTR_SODA_VERSION_METHOD

•

Last-Modified Time Stamp Column Name — OCI_ATTR_SODA_MODTIME_COL_NAME

•

Last-Modified Column Index Name — OCI_ATTR_SODA_MODTIME_INDEX

•

Creation Time Stamp Column Name — OCI_ATTR_SODA_CRTIME_COL_NAME

•

Media Type Column Name — OCI_ATTR_SODA_MTYPE_COL_NAME

•

Read Only — OCI_ATTR_SODA_READONLY

OCI_ATTR_SODA_COLL_NAME
Mode
READ

A-62

Appendix A

SODA Collection Handle Attributes

Description
Specifies the name of the collection.
Attribute Data Type
oratext *

OCI_ATTR_SODA_DESCRIPTOR
Mode
READ
Description
Specifies the descriptor to which the collection is mapped.
Attribute Data Type
oratext *

OCI_ATTR_SODA_SCHEMA
Mode
READ
Description
Specifies the name of the Oracle Database schema that owns the table or view to
which the collection is mapped.
Attribute Data Type
oratext *

OCI_ATTR_SODA_TABLE_NAME
Mode
READ
Description
Specifies the name of the table to which the collection is mapped.
Attribute Data Type
oratext *

OCI_ATTR_SODA_VIEW_NAME
Mode
READ
Description
Specifies the name of the view to which the collection is mapped.
Attribute Data Type
oratext *

OCI_ATTR_SODA_KEY_COL_NAME
Mode
READ

A-63

Appendix A

SODA Collection Handle Attributes

Description
Specifies the name of the column that stores the document key.
Attribute Data Type
oratext *

OCI_ATTR_SODA_KEY_SQL_TYPE
Mode
READ
Description
Specifies the SQL data type of the column that stores the document key. Valid values
include:
•

SQLT_CHR for VARCHAR2

•

SLQT_BIN for RAW

•

SQLT_NUM for NUMBER

Attribute Data Type
ub1

OCI_ATTR_SODA_KEY_MAX_LEN
Mode
READ
Description
Specifies the maximum length of the key column in bytes. This component applies
only to keys of type VARCHAR2. At least 32 bytes if key assignment method is UUID or
GUID. See OCI_ATTR_SODA_KEY_ASSIGN_METHOD.

See Also:
OCI_ATTR_SODA_KEY_SQL_TYPE
Attribute Data Type
ub4

OCI_ATTR_SODA_KEY_ASSIGN_METHOD
Mode
READ
Description
Specifies the OCI value for the corresponding value for this component method used
to assign keys to objects that are inserted into the collection. UUID, GUID, SEQUENCE, and
CLIENT are the corresponding valid values for this component, as it would appear in
the JSON metadata. The valid values for this attribute include:
•

OCI_SODA_KEY_METHOD_UUID for UUID, which is the corresponding value for this

component, as it would appear in the JSON metadata.

A-64

Appendix A

SODA Collection Handle Attributes

•

OCI_SODA_KEY_METHOD_GUID for GUID, which is the corresponding value for this

component, as it would appear in the JSON metadata.
•

OCI_SODA_KEY_METHOD_SEQUENCE for SEQUENCE, which is the corresponding value for

this component, as it would appear in the JSON metadata.
•

OCI_SODA_KEY_METHOD_CLIENT for CLIENT, which is the corresponding value for this

component, as it would appear in the JSON metadata.
See https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdi/index.html
for more information about key assignment methods for the collection metadata
component Key Column Assignment Method.
Attribute Data Type
ub1

OCI_ATTR_SODA_KEY_SEQ_NAME
Mode
READ
Description
Specifies the name of the database sequence that generates keys for documents that
are inserted into a collection if the key assignment method is SEQUENCE.

Note:
If you drop a collection using SODA for OCI, the sequence used for key
generation is not dropped. This is because it might not have been created
using SODA for OCI. To drop the sequence, use SQL command DROP
SEQUENCE, after first dropping the collection.

See Also:
•

OCI_ATTR_SODA_KEY_ASSIGN_METHOD

•

Oracle Database SQL Language Reference for information about DROP
SEQUENCE

•

Oracle Database Concepts

Attribute Data Type
oratext *

OCI_ATTR_SODA_CTNT_COL_NAME
Mode
READ
Description
Specifies the name of the column that stores the document content.

A-65

Appendix A

SODA Collection Handle Attributes

Attribute Data Type
oratext *

OCI_ATTR_SODA_CTNT_SQL_TYPE
Mode
READ
Description
Specifies the SQL data type of the column that stores the document content. Valid
values include:
•

SQLT_CHR for VARCHAR2

•

SQLT_CLOB for CLOB,

•

SQLT_BLOB for BLOB

Attribute Data Type
ub1

OCI_ATTR_SODA_CTNT_MAX_LEN
Mode
READ
Description
Specifies the maximum length of the content column in bytes. This component applies
only to content of type VARCHAR2. The default value is 4000 bytes.

See Also:
•

OCI_ATTR_SODA_CTNT_SQL_TYPE

•

Oracle Database SQL Language Reference for information about
extended data types

Attribute Data Type
ub4

OCI_ATTR_SODA_CTNT_VALIDATION
Mode
READ
Description
Specifies the OCI value for the corresponding syntax to which JSON content must
conform. The valid values for this attribute include:
•

OCI_SODA_JSON_VALIDATION_STRICT for STRICT, which is the corresponding value as it

appears in the JSON collection metadata.
See https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdi/
index.html for more information about the STRICT syntax.

A-66

Appendix A

SODA Collection Handle Attributes

•

OCI_COLL_JSON_VALIDATION_LAX for LAX, which is the corresponding value as it

appears in the JSON collection metadata.
See https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdi/
index.html for more information about the LAX syntax.
•

OCI_SODA_JSON_VALIDATION_STD for STANDARD, which is the corresponding value as it

appears in the JSON collection metadata.
See https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdi/
index.html for more information about the STANDARD syntax.
Attribute Data Type
ub4

OCI_ATTR_SODA_CTNT_COMPRESS
Mode
READ
Description
Specifies the OCI value for the corresponding value for the SecureFiles LOB
compression setting as it appears in the JSON collection metadata. The valid values
for this attribute include:
•

OCI_SODA_LOB_COMPRESS_NONE for NONE, which is the corresponding value as it

appears in the JSON collection metadata.
•

OCI_SODA_LOB_COMPRESS_HIGH for HIGH, which is the corresponding value as it

appears in the JSON collection metadata.
•

OCI_SODA_LOB_COMPRESS_MEDIUM for MEDIUM, which is the corresponding value as it

appears in the JSON collection metadata.
•

OCI_SODA_LOB_COMPRESS_LOW for LOW, which is the corresponding value as it appears

in the JSON collection metadata.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for
information about SecureFiles LOB storage
Attribute Data Type
ub1

OCI_ATTR_SODA_CTNT_CACHE
Mode
READ
Description
Specifies the SecureFiles LOB cache setting.

A-67

Appendix A

SODA Collection Handle Attributes

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for
information about SecureFiles LOB storage
Attribute Data Type
boolean

OCI_ATTR_SODA_CTNT_ENCRYPT
Mode
READ
Description
Specifies the OCI value for the corresponding value for the SecureFiles LOB
encryption setting as it appears in the JSON collection metadata. The valid values for
this attribute include:
•

OCI_SODA_LOB_ENCRYPT_NONE for NONE, which is the corresponding value as it appears

in the JSON collection metadata.
•

OCI_SODA_LOB_ENCRYPT_3DES168 for 3DES168, which is the corresponding value as it

appears in the JSON collection metadata.
•

OCI_SODA_LOB_ENCRYPT_AES128 for AES128, which is the corresponding value as it

appears in the JSON collection metadata.
•

OCI_SODA_LOB_ENCRYPT_AES192 for AES192, which is the corresponding value as it

appears in the JSON collection metadata.
•

OCI_SODA_LOB_ENCRYPT_AES256 for AES256, which is the corresponding value as it

appears in the JSON collection metadata.

See Also:
Oracle Database SecureFiles and Large Objects Developer's Guide for
information about SecureFiles LOB storage
Attribute Data Type
ub1

OCI_ATTR_SODA_VERSION_COL_NAME
Mode
READ
Description
Specifies the name of the column that stores the document version.
Attribute Data Type
oratext *

A-68

Appendix A

SODA Collection Handle Attributes

OCI_ATTR_SODA_VERSION_METHOD
Mode
READ
Description
Specifies the OCI value for the corresponding method used to compute version
values for objects when they are inserted into a collection or replaced as it appears in
the JSON collection metadata. The valid values for this attribute include:
•

OCI_SODA_VERSION_UUID for UUID, which is the corresponding value as it appears in

the JSON collection metadata
•

OCI_SODA_VERSION_TIMESTAMP for TIMESTAMP, which is the corresponding value as it

appears in the JSON collection metadata
•

OCI_SODA_VERSION_MD5 for MD5, which is the corresponding value as it appears in the

JSON collection metadata
•

OCI_SODA_VERSION_SHA256 for SHA256, which is the corresponding value as it appears

in the JSON collection metadata
•

OCI_SODA_VERSION_SEQUENTIAL for SEQUENTIAL, which is the corresponding value as it

appears in the JSON collection metadata
•

OCI_SODA_VERSION_NONE for NONE, which is the corresponding value as it appears in

the JSON collection metadata
See https://docs.oracle.com/en/database/oracle/oracle-database/18/adsdi/index.html
for more information about version generation methods for the collection metadata
component Version Column Generation Method.
Attribute Data Type
ub1

OCI_ATTR_SODA_MODTIME_COL_NAME
Mode
READ
Description
Specifies the name of the column that stores the last-modified time stamp of the
document.
Attribute Data Type
oratext *

OCI_ATTR_SODA_MODTIME_INDEX
Mode
READ
Description
Specifies the name of the index on the last-modified column.
Attribute Data Type
oratext *

A-69

Appendix A

LOB Descriptor and LOB Locator Attributes

OCI_ATTR_SODA_CRTIME_COL_NAME
Mode
READ
Description
Specifies the name of the column that stores the creation time stamp of the
document.
Attribute Data Type
oratext *

OCI_ATTR_SODA_MTYPE_COL_NAME
Mode
READ
Description
Specifies the name of the column that stores the media type of the document. A
media type column is needed if the collection is to be heterogeneous, that is, it can
store documents other than JSON.
Attribute Data Type
oratext *

OCI_ATTR_SODA_READONLY
Mode
READ
Description
Specifies whether the collection is read-only.
Attribute Data Type
boolean

A.17 LOB Descriptor and LOB Locator Attributes
Lists and describes LOB locator attributes.
The following attributes are used for the parameter descriptor.
OCI_ATTR_LOBEMPTY
Mode
WRITE
Description
Sets the internal LOB locator to empty. The locator can then be used as a bind
variable for an INSERT or UPDATE statement to initialize the LOB to empty. Once the
LOB is empty, OCILobWrite2() or OCILobWrite() (deprecated) can be called to
populate the LOB with data. This attribute is only valid for internal LOBs (that is, BLOB,
CLOB, NCLOB).
Applications should pass the address of a ub4 that has a value of 0; for example,
declare the following:

A-70

Appendix A

Complex Object Attributes

ub4 lobEmpty = 0

Then they should pass the address: &lobEmpty.
Attribute Data Type
ub4 *

OCI_ATTR_LOB_REMOTE
Mode
READ
Description
Determines whether the LOB locator belongs to a local database table or a remote
database table. The value TRUE indicates that the LOB locator is from a remote
database table. The application must fetch the LOB descriptor from the database
before using this attribute.
Only the server can set this value. If an application tries to set this attribute, then an
ORA-24315 error is raised.
Attribute Data Type
boolean

OCI_ATTR_LOB_TYPE
Mode
READ
Description
Gets the LOB type from the LOB descriptor.
Attribute Data Type
ub2

A.18 Complex Object Attributes
Lists and describes complex object attributes.
The following attributes are used for complex objects.

See Also:
Complex Object Retrieval

A.18.1 Complex Object Retrieval Handle Attributes
Lists and describes complex object retrieval handle attributes.
The following attributes are used for the complex object retrieval handle.

A-71

Appendix A

Streams Advanced Queuing Descriptor Attributes

OCI_ATTR_COMPLEXOBJECT_LEVEL
Mode
WRITE
Description
The depth level for complex object retrieval.
Attribute Data Type
ub4 *

OCI_ATTR_COMPLEXOBJECT_COLL_OUTOFLINE
Mode
WRITE
Description
Whether to fetch collection attributes in an object type out-of-line.
Attribute Data Type
ub1 *

A.18.2 Complex Object Retrieval Descriptor Attributes
Lists and describes complex object retrieval descriptor attributes.
The following attributes are used for the complex object retrieval descriptor.
OCI_ATTR_COMPLEXOBJECTCOMP_TYPE
Mode
WRITE
Description
A type of REF to follow for complex object retrieval.
Attribute Data Type
void *

OCI_ATTR_COMPLEXOBJECTCOMP_TYPE_LEVEL
Mode
WRITE
Description
Depth level for the following REFs of type OCI_ATTR_COMPLEXOBJECTCOMP_TYPE.
Attribute Data Type
ub4 *

A.19 Streams Advanced Queuing Descriptor Attributes
Lists and describes Streams Advanced Queuing descriptor attributes
The following attributes are used for the streams advanced queuing descriptor.

A-72

Appendix A

Streams Advanced Queuing Descriptor Attributes

See Also:
Oracle Database Advanced Queuing User's Guide

A.19.1 OCIAQEnqOptions Descriptor Attributes
Lists and describes OCIAQEnqOptions descriptor attributes.
The following attributes are properties of the OCIAQEnqOptions descriptor.
OCI_ATTR_MSG_DELIVERY_MODE
Mode
WRITE
Description
The enqueue call can enqueue a persistent or buffered message into a queue, by
setting the OCI_ATTR_MSG_DELIVERY_MODE attribute in the OCIAQEnqOptions descriptor to
OCI_MSG_PERSISTENT or OCI_MSG_BUFFERED, respectively. The default value for this
attribute is OCI_MSG_PERSISTENT.
Attribute Data Type
ub2

OCI_ATTR_RELATIVE_MSGID
Mode
READ/WRITE
Description
This feature is deprecated and may be removed in a future release.
Specifies the message identifier of the message that is referenced in the sequence
deviation operation. This value is valid if and only if OCI_ENQ_BEFORE is specified in
OCI_ATTR_SEQUENCE_DIVISION. This value is ignored if the sequence deviation is not
specified.
Attribute Data Type
OCIRaw *

OCI_ATTR_SEQUENCE_DEVIATION
Mode
READ/WRITE
Description
This feature is deprecated for new applications, but it is retained for compatibility.
It specifies whether the message being enqueued should be dequeued before other
messages in the queue.
Attribute Data Type
ub4

A-73

Appendix A

Streams Advanced Queuing Descriptor Attributes

Valid Values
The only valid values are:
•

OCI_ENQ_BEFORE - The message is enqueued ahead of the message specified by
OCI_ATTR_RELATIVE_MSGID.

•

OCI_ENQ_TOP - The message is enqueued ahead of any other messages.

OCI_ATTR_TRANSFORMATION
Mode
READ/WRITE
Description
The name of the transformation that must be applied before the message is enqueued
into the database. The transformation must be created using DBMS_TRANSFORM.
Attribute Data Type
oratext *

OCI_ATTR_VISIBILITY
Mode
READ/WRITE
Description
Specifies the transactional behavior of the enqueue request.
Attribute Data Type
ub4

Valid Values
The only valid values are:
•

OCI_ENQ_ON_COMMIT - The enqueue is part of the current transaction. The operation

is complete when the transaction commits. This is the default case.
•

OCI_ENQ_IMMEDIATE - The enqueue is not part of the current transaction. The

operation constitutes a transaction of its own.

A.19.2 OCIAQDeqOptions Descriptor Attributes
Lists and describes OCIAQDeqOptions descriptor attributes.
The following attributes are properties of the OCIAQDeqOptions descriptor.
OCI_ATTR_CONSUMER_NAME
Mode
READ/WRITE
Description
Name of the consumer. Only those messages matching the consumer name are
accessed. If a queue is not set up for multiple consumers, this field should be set to
null.
Attribute Data Type
oratext *

A-74

Appendix A

Streams Advanced Queuing Descriptor Attributes

OCI_ATTR_CORRELATION
Mode
READ/WRITE
Description
Specifies the correlation identifier of the message to be dequeued. Special patternmatching characters, such as the percent sign (%) and the underscore (_), can be
used. If multiple messages satisfy the pattern, the order of dequeuing is
undetermined.
Attribute Data Type
oratext *

OCI_ATTR_DEQ_MODE
Mode
READ/WRITE
Description
Specifies the locking behavior associated with the dequeue.
Attribute Data Type
ub4

Valid Values
The only valid values are:
•

OCI_DEQ_BROWSE - Read the message without acquiring any lock on the message.
This is equivalent to a SELECT statement.

•

OCI_DEQ_LOCKED - Read and obtain a write lock on the message. The lock lasts for
the duration of the transaction. This is equivalent to a SELECT FOR UPDATE statement.

•

OCI_DEQ_REMOVE - Read the message and update or delete it. This is the default.

The message can be retained in the queue table based on the retention
properties.
•

OCI_DEQ_REMOVE_NODATA - Confirm receipt of the message, but do not deliver the

actual message content.
OCI_ATTR_DEQ_MSGID
Mode
READ/WRITE
Description
Specifies the message identifier of the message to be dequeued.
Attribute Data Type
OCIRaw *

OCI_ATTR_DEQCOND
Mode
READ/WRITE

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Description
This attribute is a Boolean expression similar to the WHERE clause of a SQL query. This
Boolean expression can include conditions on message properties, user data
properties (object payloads only), and PL/SQL or SQL functions.
To specify dequeue conditions on a message payload (object payload), use attributes
of the object type in clauses. You must prefix each attribute with tab.user_data as a
qualifier to indicate the specific column of the queue table that stores the payload.
The attribute cannot exceed 4000 characters. If multiple messages satisfy the
dequeue condition, then the order of dequeuing is indeterminate, and the sort order of
the queue is not honored.
Attribute Data Type
oratext *

Example
checkerr(errhp, OCIAttrSet(deqopt, OCI_DTYPE_AQDEQ_OPTIONS,
(dvoid *)"tab.priority between 2 and 4" ,
strlen("tab.priority between 2 and 4"),
OCI_ATTR_DEQCOND, errhp));

OCI_ATTR_MSG_DELIVERY_MODE
Mode
WRITE
Description
You can specify the dequeue call to dequeue persistent, buffered, or both kinds of
messages from a queue, by setting the OCI_ATTR_MSG_DELIVERY_MODE attribute in the
OCIAQDeqOptions descriptor to OCI_MSG_PERSISTENT, OCI_MSG_BUFFERED, or
OCI_MSG_PERSISTENT_OR_BUFFERED, respectively. The default value for this attribute is
OCI_MSG_PERSISTENT.
Attribute Data Type
ub2

OCI_ATTR_NAVIGATION
Mode
READ/WRITE
Description
Specifies the position of the message that is retrieved. First, the position is
determined. Second, the search criterion is applied. Finally, the message is retrieved.
Attribute Data Type
ub4

Valid Values
The only valid values are:
•

OCI_DEQ_FIRST_MSG - Retrieves the first available message that matches the search

criteria. This resets the position to the beginning of the queue.

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•

OCI_DEQ_NEXT_MSG - Retrieves the next available message that matches the search

criteria. If the previous message belongs to a message group, AQ retrieves the
next available message that matches the search criteria and belongs to the
message group. This is the default.
•

OCI_DEQ_NEXT_TRANSACTION - Skips the remainder of the current transaction group (if

any) and retrieves the first message of the next transaction group. This option can
only be used if message grouping is enabled for the current queue.
•

OCI_DEQ_FIRST_MSG_MULTI_GROUP - Indicates that a call to OCIAQDeqArray() resets the

position to the beginning of the queue and dequeue messages (possibly across
different transaction groups) that are available and match the search criteria, until
reaching the iters limit. To distinguish between transaction groups, a new
message property, OCI_ATTR_TRANSACTION_NO, is defined. All messages belonging
to the same transaction group have the same value for this message property.
•

OCI_DEQ_NEXT_MSG_MULTI_GROUP - Indicates that a call to OCIAQDeqArray() dequeues

the next set of messages (possibly across different transaction groups) that are
available and match the search criteria, until reaching the iters limit. To
distinguish between transaction groups, a new message property,
OCI_ATTR_TRANSACTION_NO, is defined. All messages belonging to the same
transaction group have the same value for this message property.
OCI_ATTR_TRANSFORMATION
Mode
READ/WRITE
Description
The name of the transformation that must be applied after the message is dequeued
but before returning it to the dequeuing application. The transformation must be
created using DBMS_TRANSFORM.
Attribute Data Type
oratext *

OCI_ATTR_VISIBILITY
Mode
READ/WRITE
Description
Specifies whether the new message is dequeued as part of the current transaction.
The visibility parameter is ignored when using the BROWSE mode.
Attribute Data Type
ub4

Valid Values
The only valid values are:
•

OCI_DEQ_ON_COMMIT - The dequeue is part of the current transaction. This is the

default.
•

OCI_DEQ_IMMEDIATE - The dequeued message is not part of the current transaction.

It constitutes a transaction on its own.

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OCI_ATTR_WAIT
Mode
READ/WRITE
Description
Specifies the wait time if no message is currently available that matches the search
criteria. This parameter is ignored if messages in the same group are being
dequeued.
Attribute Data Type
ub4

Valid Values
Any ub4 value is valid, but the following predefined constants are provided:
•

OCI_DEQ_WAIT_FOREVER - Wait forever. This is the default.

•

OCI_DEQ_NO_WAIT - Do not wait.

Note:
If the OCI_DEQ_NO_WAIT option is used to poll a queue, then messages are not
dequeued after polling an empty queue. Use the OCI_DEQ_FIRST_MSG option
instead of the default OCI_DEQ_NEXT_MSG setting of OCI_ATTR_NAVIGATION. You
can also use a nonzero wait setting (1 is suggested) of OCI_ATTR_WAIT for the
dequeue.

A.19.3 OCIAQMsgProperties Descriptor Attributes
Lists and describes OCIAQMsgProperties descriptor attributes.
The following attributes are properties of the OCIAQMsgProperties descriptor.
OCI_ATTR_ATTEMPTS
Mode
READ

Description
Specifies the number of attempts that have been made to dequeue the message. This
parameter cannot be set at enqueue time.
Attribute Data Type
sb4

Valid Values
Any sb4 value is valid.
OCI_ATTR_CORRELATION
Mode
READ/WRITE

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Description
Specifies the identification supplied by the producer for a message at enqueuing.
Attribute Data Type
oratext *

Valid Values
Any string up to 128 bytes is valid.
OCI_ATTR_DELAY
Mode
READ/WRITE
Description
Specifies the number of seconds to delay the enqueued message. The delay
represents the number of seconds after which a message is available for dequeuing.
Dequeuing by message ID (msgid) overrides the delay specification. A message
enqueued with delay set is in the WAITING state; when the delay expires the messages
goes to the READY state. DELAY processing requires the queue monitor to be started.
Note that the delay is set by the producer who enqueues the message.
Attribute Data Type
sb4

Valid Values
Any sb4 value is valid, but the following predefined constant is available:
OCI_MSG_NO_DELAY - Indicates that the message is available for immediate
dequeuing.
OCI_ATTR_ENQ_TIME
Mode
READ
Description
Specifies the time that the message was enqueued. This value is determined by the
system and cannot be set by the user.
Attribute Data Type
OCIDate

OCI_ATTR_EXCEPTION_QUEUE
Mode
READ/WRITE
Description
Specifies the name of the queue to which the message is moved if it cannot be
processed successfully. Messages are moved in two cases: If the number of
unsuccessful dequeue attempts has exceeded max_retries; or if the message has
expired. All messages in the exception queue are in the EXPIRED state.
The default is the exception queue associated with the queue table. If the exception
queue specified does not exist at the time of the move, the message is moved to the
default exception queue associated with the queue table, and a warning is logged in

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the alert file. If the default exception queue is used, the parameter returns a NULL
value at dequeue time.
This attribute must refer to a valid queue name.
Attribute Data Type
oratext *

OCI_ATTR_EXPIRATION
Mode
READ/WRITE
Description
Specifies the expiration of the message. It determines, in seconds, how long the
message is available for dequeuing. This parameter is an offset from the delay.
Expiration processing requires the queue monitor to be running.
While waiting for expiration, the message remains in the READY state. If the message is
not dequeued before it expires, it is moved to the exception queue in the EXPIRED
state.
Attribute Data Type
sb4

Valid Values
Any sb4 value is valid, but the following predefined constant is available:
OCI_MSG_NO_EXPIRATION - The message never expires.
OCI_ATTR_MSG_DELIVERY_MODE
Mode
READ
Description
After a dequeue call, the OCI client can read the OCI_ATTR_MSG_DELIVERY_MODE attribute
in the OCIAQMsgProperties descriptor to determine whether a persistent or buffered
message was dequeued. The value of the attribute is OCI_MSG_PERSISTENT for
persistent messages and OCI_MSG_BUFFERED for buffered messages.
Attribute Data Type
ub2

OCI_ATTR_MSG_STATE
Mode
READ
Description
Specifies the state of the message at the time of the dequeue. This parameter cannot
be set at enqueue time.
Attribute Data Type
ub4

Valid Values
Only the following values are returned:

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•

OCI_MSG_WAITING - The message delay has not yet been reached.

•

OCI_MSG_READY - The message is ready to be processed.

•

OCI_MSG_PROCESSED - The message has been processed and is retained.

•

OCI_MSG_EXPIRED - The message has been moved to the exception queue.

OCI_ATTR_ORIGINAL_MSGID
Mode
READ/WRITE
Description
The ID of the message in the last queue that generated this message. When a
message is propagated from one queue to another, this attribute identifies the ID of
the queue from which it was last propagated. When a message has been propagated
through multiple queues, this attribute identifies the ID of the message in the last
queue that generated this message, not the first queue.
Attribute Data Type
OCIRaw *

OCI_ATTR_PRIORITY
Mode
READ/WRITE
Description
Specifies the priority of the message. A smaller number indicates a higher priority.
The priority can be any number, including negative numbers.
The default value is zero.
Attribute Data Type
sb4

OCI_ATTR_RECIPIENT_LIST
Mode
WRITE
Description
This parameter is only valid for queues that allow multiple consumers. The default
recipients are the queue subscribers. This parameter is not returned to a consumer at
dequeue time.
Attribute Data Type
OCIAQAgent **

OCI_ATTR_SENDER_ID
Mode
READ/WRITE
Description
Identifies the original sender of a message.

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Attribute Data Type
OCIAgent *

OCI_ATTR_TRANSACTION_NO
Mode
READ
Description
For transaction-grouped queues, this identifies the transaction group of the message.
This attribute is populated after a successful OCIAQDeqArray() call. All messages in a
group have the same value for this attribute. This attribute cannot be used by the
OCIAQEnqArray() call to set the transaction group for an enqueued message.
Attribute Data Type
oratext *

A.19.4 OCIAQAgent Descriptor Attributes
Lists and describes OCIAQAgent descriptor attributes.
The following attributes are properties of the OCIAQAgent descriptor.
OCI_ATTR_AGENT_ADDRESS
Mode
READ/WRITE
Description
Protocol-specific address of the recipient. If the protocol is 0 (default), the address is
of the form [schema.]queue[@dblink].
Attribute Data Type
oratext *

Valid Values
Can be any string up to 128 bytes.
OCI_ATTR_AGENT_NAME
Mode
READ/WRITE
Description
Name of a producer or consumer of a message.
Attribute Data Type
oratext *

Valid Values
Can be any Oracle Database identifier, up to 30 bytes.
OCI_ATTR_AGENT_PROTOCOL
Mode
READ/WRITE

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Description
Protocol to interpret the address and propagate the message. The default (and
currently the only supported) value is 0.
Attribute Data Type
ub1

Valid Values
The only valid value is zero, which is also the default.

A.19.5 OCIServerDNs Descriptor Attributes
Lists and describes OCIServerDNs descriptor attributes.
The following attributes are properties of the OCIServerDNs descriptor.
OCI_ATTR_DN_COUNT
Mode
READ
Description
The number of database servers in the descriptor.
Attribute Data Type
ub2

OCI_ATTR_SERVER_DN
Mode
READ/WRITE
Description
For read mode, this attribute returns the list of Oracle Database distinguished names
that are already inserted into the descriptor.
For write mode, this attribute takes the distinguished name of an Oracle Database.
Attribute Data Type
oratext **/oratext *

A.20 Subscription Handle Attributes
Lists and describes subscription handle attributes.
The following attributes are used for the subscription handle.

See Also:
•

Publish-Subscribe Notification in OCI

•

About Continuous Query Notification

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OCI_ATTR_SERVER_DNS
Mode
READ/WRITE
Description
The distinguished names of the Oracle database that the client is interested in for the
registration.
Attribute Data Type
OCIServerDNs *

OCI_ATTR_SUBSCR_CALLBACK
Mode
READ/WRITE
Description
Subscription callback. If the attribute OCI_ATTR_SUBSCR_RECPTPROTO is set to
OCI_SUBSCR_PROTO_OCI or is left not set, then this attribute must be set before the
subscription handle can be passed into the registration call
OCISubscriptionRegister().
Attribute Data Type
ub4 (void *, OCISubscription *, void *, ub4, void *, ub4)

OCI_ATTR_SUBSCR_CQ_QOSFLAGS
Mode
WRITE
Description
Sets QOS (quality of service flags) specific to continuous query (CQ) notifications. For
the possible values you can pass, see the section on using OCI subscription handle
attributes for CQN in Oracle Database Development Guide.
Attribute Data Type
ub4 *

OCI_ATTR_SUBSCR_CTX
Mode
READ/WRITE
Description
Context that the client wants to get passed to the user callback denoted by
OCI_ATTR_SUBSCR_CALLBACK when it gets invoked by the system. If the attribute
OCI_ATTR_SUBSCR_RECPTPROTO is set to OCI_SUBSCR_PROTO_OCI or is left not set, then this
attribute must be set before the subscription handle can be passed into the
registration call OCI Subscription Register().
Attribute Data Type
void *

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OCI_ATTR_SUBSCR_HOSTADDR
Mode
READ/WRITE
Description
Before registering for notification using OCISubscriptionRegister(), specify the client
IP (in either IPv4 or IPv6 format) of the listening endpoint of the OCI notification client
to which the notification is sent. Enter either IPv4 addresses in dotted decimal format,
for example, 192.0.2.34, or IPv6 addresses in hexadecimal format, for example,
2001:0db8:0000:0000:0217:f2ff:fe4b:4ced.

See Also:
Oracle Database Net Services Administrator's Guide for more information
about the IPv6 format for IP addresses
Attribute Data Type
text *

Example
/* Set notification client address*/
text ipaddr[16] = "192.0.2.34";
(void) OCIAttrSet((dvoid *) envhp, (ub4) OCI_HTYPE_ENV,
(dvoid *) ipaddr, (ub4) strlen(ipaddr),
(ub4) OCI_ATTR_SUBSCR_HOSTADDR, errhp);

OCI_ATTR_SUBSCR_IPADDR
Mode
READ/WRITE
Description
The client IP address (IPv4 or IPv6) on which an OCI client registered for notification
listens, to receive notifications. For example, IPv4 address in dotted decimal format
such as 192.1.2.34 or IPv6 address in hexadecimal format such as
2001:0db8:0000:0000:0217:f2ff:fe4b:4ced.

See Also:
Oracle Database Net Services Administrator's Guide for more information
about the IPv6 format for IP addresses
Attribute Data Type
oratext *

OCI_ATTR_SUBSCR_NAME
Mode
READ/WRITE

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Description
Subscription name. All subscriptions are identified by a subscription name. A
subscription name consists of a sequence of bytes of specified length. The length in
bytes of the name must be specified as it is not assumed that the name is NULLterminated. This is important because the name could contain multibyte characters.
Clients can set the subscription name attribute of a subscription handle using an
OCIAttrSet() call and by specifying a handle type of OCI_HTYPE_SUBSCR and an attribute
type of OCI_ATTR_SUBSCR_NAME.
All of the subscription callbacks need a subscription handle with the
OCI_ATTR_SUBSCR_NAME and OCI_ATTR_SUBSCR_NAMESPACE attributes set. If the attributes are
not set, an error is returned. The subscription name that is set for the subscription
handle must be consistent with its namespace.
Attribute Data Type
oratext *

OCI_ATTR_SUBSCR_NAMESPACE
Mode
READ/WRITE
Description
Namespace in which the subscription handle is used. The valid values for this
attribute are OCI_SUBSCR_NAMESPACE_AQ, OCI_SUBSCR_NAMESPACE_DBCHANGE, and
OCI_SUBSCR_NAMESPACE_ANONYMOUS.
The subscription name that is set for the subscription handle must be consistent with
its namespace.
Attribute Data Type
ub4 *

OCI_ATTR_SUBSCR_NTFN_GROUPING_CLASS
Mode
READ/WRITE
Description
Notification grouping class. If set to 0 (the default) all other notification grouping
attributes must be 0. It is implemented for time in the latest release and is the only
current criterion for grouping. Can be set to OCI_SUBSCR_NTFN_GROUPING_CLASS_TIME.

Note:
OCI_OBJECT mode is required when using grouping notifications.

Attribute Data Type
ub1 *

OCI_ATTR_SUBSCR_NTFN_GROUPING_REPEAT_COUNT
Mode
READ/WRITE

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Description
How many times to do the grouping. Notification repeat count. Positive integer. Can
be set to OCI_NTFN_GROUPING_FOREVER to send grouping notifications forever.
Attribute Data Type
sb4 *

OCI_ATTR_SUBSCR_NTFN_GROUPING_START_TIME
Mode
READ/WRITE
Description
The time grouping starts. Set to a valid TIMESTAMP WITH TIME ZONE. The default is the
current TIMESTAMP WITH TIME ZONE.
Attribute Data Type
OCIDateTime */OCIDateTime **

OCI_ATTR_SUBSCR_NTFN_GROUPING_TYPE
Mode
READ/WRITE
Description
The format of the grouping notification: whether a summary of all events in the group
or just the last event in the group. Use OCIAttrSet() to set to one of the following
notification grouping types: OCI_SUBSCR_NTFN_TYPE_SUMMARY or
OCI_SUBSCR_NTFN_TYPE_LAST. Summary of notifications is the default. The other choice is
the last notification.
Attribute Data Type
ub1 *

OCI_ATTR_SUBSCR_NTFN_GROUPING_VALUE
Mode
READ/WRITE
Description
Specifies the value for the grouping class. For time, this is the time-period of grouping
notifications specified in seconds, that is, the time after which grouping notification is
sent periodically until OCI_ATTR_SUBSCR_NTFN_GROUPING_REPEAT_COUNT is exhausted.
Attribute Data Type
ub4 *

OCI_ATTR_SUBSCR_PAYLOAD
Mode
READ/WRITE
Description
Buffer that corresponds to the payload that must be sent along with the notification.
The length of the buffer can also be specified in the same set attribute call. This

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attribute must be set before a post can be performed on a subscription. For the
current release, only an untyped (ub1 *) payload is supported.
Attribute Data Type
ub1 *

OCI_ATTR_SUBSCR_QOSFLAGS
Mode
READ/WRITE
Description
Quality of service levels of the server. The possible settings are:
•

OCI_SUBSCR_QOS_RELIABLE - Reliable. If the database fails, it does not lose

notification. Not supported for nonpersistent queues or buffered messaging.
•

OCI_SUBSCR_QOS_PURGE_ON_NTFN - Once received, purge notification and remove

subscription.
•

OCI_SUBSCR_QOS_PAYLOAD - Payload notification.

Attribute Data Type
ub4 *

OCI_ATTR_SUBSCR_RECPT
Mode
READ/WRITE
Description
The name of the recipient of the notification when the attribute
OCI_ATTR_SUBSCR_RECPTPROTO is set to OCI_SUBSCR_PROTO_MAIL, OCI_SUBSCR_PROTO_HTTP, or
OCI_SUBSCR_PROTO_SERVER.
For OCI_SUBSCR_PROTO_HTTP, OCI_ATTR_SUBSCR_RECPT denotes the HTTP URL (for
example, http://www.oracle.com:80) to which notification is sent. The validity of the
HTTP URL is never checked by the database.
For OCI_SUBSCR_PROTO_MAIL, OCI_ATTR_SUBSCR_RECPT denotes the email address (for
example, xyz@oracle.com) to which the notification is sent. The validity of the email
address is never checked by the database system.
For OCI_SUBSCR_PROTO_SERVER, OCI_ATTR_SUBSCR_RECPT denotes the database procedure
(for example: schema.procedure) that is invoked when there is a notification. The
subscriber must have appropriate permissions on the procedure for it to be executed.

See Also:
Notification Procedure for information about procedure definition
Attribute Data Type
oratext *

OCI_ATTR_SUBSCR_RECPTPRES
Mode
READ/WRITE

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Description
The presentation with which the client wants to receive the notification. The valid
values for this are OCI_SUBSCR_PRES_DEFAULT and OCI_SUBSCR_PRES_XML.
If not set, this attribute defaults to OCI_SUBSCR_PRES_DEFAULT.
For event notification in XML presentation, set this attribute to OCI_SUBSCR_PRES_XML.
XML presentation is limited to 2000 bytes. Otherwise, leave it unset or set it to
OCI_SUBSCR_PRES_DEFAULT.
Attribute Data Type
ub4

OCI_ATTR_SUBSCR_RECPTPROTO
Mode
READ/WRITE
Description
The protocol with which the client wants to receive the notification. The valid values
for this are:
•

OCI_SUBSCR_PROTO_OCI

•

OCI_SUBSCR_PROTO_MAIL

•

OCI_SUBSCR_PROTO_SERVER

•

OCI_SUBSCR_PROTO_HTTP

If an OCI client wants to receive the event notification, then you should set this
attribute to OCI_SUBSCR_PROTO_OCI.
If you want an email to be sent on event notification, then set this attribute to
OCI_SUBSCR_PROTO_MAIL. If you want a PL/SQL procedure to be invoked in the database
on event notification, then set this attribute to OCI_SUBSCR_PROTO_SERVER. If you want an
HTTP URL to be posted to on event notification, then set this attribute to
OCI_SUBSCR_PROTO_HTTP.
If not set, this attribute defaults to OCI_SUBSCR_PROTO_OCI.
For OCI_SUBSCR_PROTO_OCI, the attributes OCI_ATTR_SUBSCR_CALLBACK and
OCI_ATTR_SUBSCR_CTX must be set before the subscription handle can be passed into
the registration call OCISubscriptionRegister().
For OCI_SUBSCR_PROTO_MAIL, OCI_SUBSCR_PROTO_SERVER, and OCI_SUBSCR_PROTO_HTTP, the
attribute OCI_ATTR_SUBSCR_RECPT must be set before the subscription handle can be
passed into the registration call OCISubscriptionRegister().
Attribute Data Type
ub4 *

OCI_ATTR_SUBSCR_TIMEOUT
Mode
READ/WRITE
Description
Registration timeout interval in seconds. If 0 or not specified, then the registration is
active until the subscription is explicitly unregistered.
Attribute Data Type
ub4 *

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A.20.1 Continuous Query Notification Attributes
Lists and describes continuous query notification attributes.
The following attributes are used for continuous query notification.
OCI_ATTR_CHNF_CHANGELAG
Mode
WRITE
Description
The number of transactions that the client is to lag in continuous query notifications.
Attribute Data Type
ub4 *

OCI_ATTR_CHNF_OPERATIONS
Mode
WRITE
Description
Used to filter notifications based on operation type.

See Also:
About Continuous Query Notification for details about the flag values
Attribute Data Type
ub4 *

OCI_ATTR_CHNF_ROWIDS
Mode
WRITE
Description
If TRUE, the continuous query notification message includes row-level details, such as
operation type and ROWID. The default is FALSE.
Attribute Data Type
boolean *

OCI_ATTR_CHNF_TABLENAMES
Mode
READ
Description
Attributes provided to retrieve the list of table names that were registered. These
attributes are available from the subscription handle after the query is executed.

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Attribute Data Type
OCIColl **

A.20.2 Continuous Query Notification Descriptor Attributes
Lists and describes continuous query notification descriptor attributes.
The following attributes are used for the continuous query notification descriptor.
OCI_ATTR_CHDES_DBNAME
Mode
READ
Description
Name of the database.
Attribute Data Type
oratext **

OCI_ATTR_CHDES_NFTYPE
Mode
READ
Description
Flags describing the notification type.

See Also:
About Continuous Query Notification for the flag values
Attribute Data Type
ub4 *

OCI_ATTR_CHDES_ROW_OPFLAGS
Mode
READ
Description
Operation type: INSERT, UPDATE, DELETE, or OTHER.
Attribute Data Type
ub4 *

OCI_ATTR_CHDES_ROW_ROWID
Mode
READ
Description
String representation of a ROWID.

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Attribute Data Type
oratext **

OCI_ATTR_CHDES_TABLE_CHANGES
Mode
READ
Description
A collection type describing operations on tables. Each element of the collection is a
table continuous query descriptors (OCITableChangeDesc *) of type
OCI_DTYPE_TABLE_CHDES that has the attributes that begin with OCI_ATTR_CHDES_TABLE.
See the following entries.
Attribute Data Type
OCIColl **

OCI_ATTR_CHDES_TABLE_NAME
Mode
READ
Description
Schema and table name. HR.EMPLOYEES, for example.
Attribute Data Type
oratext **

OCI_ATTR_CHDES_TABLE_OPFLAGS
Mode
READ
Description
Flags describing the operations on the table.
Attribute Data Type
ub4 *

See Also:
Oracle Database Development Guide for information about the flag values
for the OCI_DTYPETABLE_CHDES continuous query notification descriptor
OCI_ATTR_CHDES_TABLE_ROW_CHANGES
Mode
READ
Description
An embedded collection describing the changes to the rows of the table. Each
element of the collection is a row continuous query descriptor (OCIRowChangeDesc *) of
type OCI_DTYPE_ROW_CHDES that has the attributes OCI_ATTR_CHDES_ROW_OPFLAGS and
OCI_ATTR_CHDES_ROW_ROWID.

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Attribute Data Type
OCIColl **

OCI_ATTR_CHDES_XID
Mode
READ
Description
The transaction ID of the message.
Attribute Data Type
OCIRaw *

See Also:
Oracle Database Development Guide for more information.

A.20.3 Notification Descriptor Attributes
Lists and describes notification descriptor attributes.
The following are attributes of the descriptor OCI_DTYPE_AQNFY.
OCI_ATTR_AQ_NTFN_GROUPING_COUNT
Mode
READ
Description
For AQ namespace. Count of notifications received in the group.
Attribute Data Type
ub4 *

OCI_ATTR_AQ_NTFN_GROUPING_ MSGID_ARRAY
Mode
READ
Description
For AQ namespace. The group: an OCI Collection of message IDs.
Attribute Data Type
OCIColl **

OCI_ATTR_CONSUMER_NAME
Mode
READ
Description
Consumer name of the notification.

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Attribute Data Type
oratext *

OCI_ATTR_MSG_PROP
Mode
READ
Description
Message properties.
Attribute Data Type
OCIAQMsgProperties **

OCI_ATTR_NFY_FLAGS
Mode
READ
Description
0 = regular, 1 = timeout notification, 2 = grouping notification.
Attribute Data Type
ub4 *

OCI_ATTR_NFY_MSGID
Mode
READ
Description
Message ID.
Attribute Data Type
OCIRaw *

OCI_ATTR_QUEUE_NAME
Mode
READ
Description
The queue name of the notification.
Attribute Data Type
oratext *

A.20.4 Invalidated Query Attributes
Lists and describes invalidated query attributes.
This section describes OCI_DTYPE_CQDES attributes.

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See Also:
Oracle Database Development Guide for more information about the
OCI_DTYPE_CQDES continuous query notification descriptor

OCI_ATTR_CQDES_OPERATION
Mode
READ
Description
The operation that occurred on the query. It can be one of two values:
OCI_EVENT_QUERYCHANGE (query result set change) or OCI_EVENT_DEREG (query
unregistered).
Attribute Data Type
ub4 *

OCI_ATTR_CQDES_QUERYID
Mode
READ
Description
Query ID of the query that was invalidated.
Attribute Data Type
ub8 *

OCI_ATTR_CQDES_TABLE_CHANGES
Mode
READ
Description
A collection of table continuous query descriptors describing DML or DDL operations
on tables that caused the query result set change. Each element of the collection is of
type OCI_DTYPE_TABLE_CHDES.
Attribute Data Type
OCIColl *

A.21 Direct Path Loading Handle Attributes
Lists and describes direct path loading handle attributes.
The following attributes are used for the direct path loading handle.

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Direct Path Loading Handle Attributes

See Also:
Direct Path Loading Overview and Direct Path Loading of Object Types for
information about direct path loading and allocating the direct path handles

A.21.1 Direct Path Context Handle (OCIDirPathCtx) Attributes
Lists and describes direct path context handle (OCIDirPathCtx) attributes.
The following attributes are used for the direct path context handle.
OCI_ATTR_BUF_SIZE
Mode
READ/WRITE
Description
Sets the size of the stream transfer buffer. Default value is 64 KB.
Attribute Data Type
ub4 */ub4 *

OCI_ATTR_CHARSET_ID
Mode
READ/WRITE
Description
Default character set ID for the character data. Note that the character set ID can be
overridden at the column level. If the character set ID is not specified at the column
level or the table level, then the Global support environment setting is used.
Attribute Data Type
ub2 */ub2 *

OCI_ATTR_DATEFORMAT
Mode
READ/WRITE
Description
Default date format string for SQLT_CHR to DTYDAT conversions. Note that the date format
string can be overridden at the column level. If date format string is not specified at
the column level or the table level, then the Global Support environment setting is
used.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_DIRPATH_DCACHE_DISABLE
Mode
READ/WRITE

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Description
Setting this attribute to 1 indicates that the date cache is to be disabled if exceeded.
The default value is 0, which means that lookups in the cache continue on cache
overflow.

See Also:
About Using a Date Cache in Direct Path Loading of Dates in OCI for a
complete description of this attribute and of the four following attributes
Attribute Data Type
ub1 */ub1 *

OCI_ATTR_DIRPATH_DCACHE_HITS
Mode
READ
Description
Queries the number of date cache hits.
Attribute Data Type
ub4 *

OCI_ATTR_DIRPATH_DCACHE_MISSES
Mode
READ
Description
Queries the current number of date cache misses.
Attribute Data Type
ub4 *

OCI_ATTR_DIRPATH_DCACHE_NUM
Mode
READ
Description
Queries the current number of entries in a date cache.
Attribute Data Type
ub4 *

OCI_ATTR_DIRPATH_DCACHE_SIZE
Mode
READ/WRITE
Description
Sets the date cache size (in elements) for a table. To disable the date cache, set this
to 0, which is the default value.

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Attribute Data Type
ub4 */ub4 *
OCI_ATTR_DIRPATH_DEF_EXP_CACHE_SIZE
Mode
READ/WRITE
Description
Specifies the number of default expressions that are evaluated at a time. The default
is 100. For default expressions that must be evaluated for every row, increasing this
value may improve performance.
Valid values: UB4
Attribute Data Type
ub4 */ub4 *

Example
ub4 default_cache = 200;
OCIAttrSet ((void *)dpctx,
(ub4)OCI_HTYPE_DIRPATH_CTX,
(void *)&default_cache,
(ub4)0, (ub4)OCI_ATTR_DIRPATH_DEF_EXP_CACHE_SIZE, errhp);

OCI_ATTR_DIRPATH_DEFAULTS
Mode
Read/Write
Description
Specifies how the direct path API handles default expressions for columns that are
not explicitly being loaded.
Valid values are:
•

OCI_DIRPATH_DEFAULTS_DEFAULT

Evaluate once, unless a sequence is involved, then evaluate every row.
Error if an unsupported default value is seen. This is the default.
•

OCI_DIRPATH_DEFAULTS_EVALUATE_ONCE

Evaluate once, at the start of the load. Error if an unsupported default value is
seen.
•

OCI_DIRPATH_DEFAULTS_EVALUATE_EVERY_ROW

Evaluate every row. Error if an unsupported default value is seen.
•

OCI_DIRPATH_DEFAULTS_IGNORE

Ignore all defaults, load NULLs.
•

OCI_DIRPATH_DEFAULTS_IGNORE_UNSUPPORTED_EVALUATE_ONCE

Ignore unsupported defaults, load NULLS, evaluate supported once.
•

OCI_DIRPATH_DEFAULTS_IGNORE_UNSUPPORTED_EVALUATE_EVERY_ROW

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Ignore unsupported defaults, load NULLS, evaluate supported every row.
Attribute Data Type
ub1 */ub1 *

Example
ub1 dirpath_handling = OCI_DIRPATH_DEFAULTS_EVALUATE_EVERY_ROW;
OCIAttrSet ((void *)dpctx,
(ub4)OCI_HTYPE_DIRPATH_CTX,
(void *)&dirpath_handling,
(ub4)0, (ub4)OCI_ATTR_DIRPATH_DEFAULTS, errhp);

OCI_ATTR_DIRPATH_FLAGS
Mode
READ/WRITE
Description
Flags used to control behavior of the load.
OCI_DIRPATH_FLAGS_VLDT 0x01 – validate format for Oracle NUMBER and DATE data when
the stream is parsed on the server. The default value is to not set this flag because it
is an expensive operation. It can be used when you suspect that there is a problem
with OCIDirPath generating invalid internal representation of dates and numbers.
Example
ub4 dirpath_flags = OCI_ATTR_DIRPATH_FLAGS_VLDT;
OCIAttrSet ((void *)dpctx,
(ub4)OCI_HTYPE_DIRPATH_CTX,
(void *)&dirpath_flags,
(ub4)0, (ub4)OCI_ATTR_DIRPATH_FLAGS, errhp);

Attribute Data Type
ub4 */ub4 *
OCI_ATTR_DIRPATH_INDEX_MAINT_METHOD
Mode
READ/WRITE
Description
Performs index row insertion on a per-row basis.
Valid value is:
OCI_DIRPATH_INDEX_MAINT_SINGLE_ROW

Attribute Data Type
ub1 */ub1 *
OCI_ATTR_DIRPATH_MODE
Mode
READ/WRITE
Description
Mode of the direct path context:

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•

OCI_DIRPATH_LOAD - Load operation (default)

•

OCI_DIRPATH_CONVERT - Convert-only operation

Attribute Data Type
ub1 */ub1 *

OCI_ATTR_DIRPATH_NO_INDEX_ERRORS
Mode
READ/WRITE
Description
When OCI_ATTR_DIRPATH_NO_INDEX_ERRORS is 1, indexes are not set as unusable at any
time during the load. If any index errors are detected, the load is aborted. That is, no
rows are loaded, and the indexes are left as is. The default is 0.
Attribute Data Type
ub1 */ub1 *
OCI_ATTR_DIRPATH_NOLOG
Mode
READ/WRITE
Description
The NOLOG attribute of each segment determines whether image redo or invalidation
redo is generated:
•

0 - Use the attribute of the segment being loaded.

•

1 - No logging. Overrides DDL statement, if necessary.

Attribute Data Type
ub1 */ub1 *

OCI_ATTR_DIRPATH_OBJ_CONSTR
Mode
READ/WRITE
Description
Indicates the object type of a substitutable object table:
OraText *obj_type; /* stores an object type name */
OCIAttrSet((void *)dpctx,
(ub4)OCI_HTYPE_DIRPATH_CTX,
(void *) obj_type,
(ub4)strlen((const char *) obj_type),
(ub4)OCI_ATTR_DIRPATH_OBJ_CONSTR, errhp);

Attribute Data Type
oratext **/oratext *

OCI_ATTR_DIRPATH_PARALLEL
Mode
READ/WRITE

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Description
Setting this value to 1 allows multiple load sessions to load the same segment
concurrently. The default is 0 (not parallel).
Attribute Data Type
ub1 */ub1 *

OCI_ATTR_DIRPATH_PGA_LIM
Mode
READ/WRITE
Description
The current partition loading memory limit. Once this limit is reached, some partition
loading will be delayed to save memory. The value is in KB.
Attribute Data Type
ub4 */ub4 *

OCI_ATTR_DIRPATH_REJECT_ROWS_REPCH
Mode
READ/WRITE
Description
If set to 1, any rows with character conversions that use the replacement character
will be rejected.
•

0 - Allow use of the replacement character in conversions.

•

1 - Reject rows if the replacement character was used during conversion.

Attribute Data Type
ub1 */ub1 *
OCI_ATTR_DIRPATH_SKIPINDEX_METHOD
Mode
READ/WRITE
Description
Indicates how the handling of unusable indexes is performed.
Valid values are:
•

OCI_DIRPATH_INDEX_MAINT_SKIP_UNUSABLE (skip unusable indexes)

•

OCI_DIRPATH_INDEX_MAINT_DONT_SKIP_UNUSABLE (do not skip unusable indexes)

•

OCI_DIRPATH_INDEX_MAINT_SKIP_ALL (skip all index maintenance)

Attribute Data Type
ub1 */ub1 *
OCI_ATTR_DIRPATH_SPILL_PASSES
Mode
READ

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Description
The number of passes required to load all partitions. If the direct path PGA limit is
exceeded, this will likely be greater than one. Increasing the PGA limit, using the
attribute OCI_ATTR_DIRPATH_PGA_LIM, can decrease the number of passes, but can also
exceed available memory.
Attribute Data Type
ub4 *

OCI_ATTR_LIST_COLUMNS
Mode
READ
Description
Returns the handle to the parameter descriptor for the column list associated with the
direct path context. The column list parameter descriptor can be retrieved after the
number of columns is set with the OCI_ATTR_NUM_COLS attribute.

See Also:
"About Accessing Column Parameter Attributes"
Attribute Data Type
OCIParam* *

OCI_ATTR_NAME
Mode
READ/WRITE
Description
Name of the table to be loaded into.
Attribute Data Type
oratext**/oratext *

OCI_ATTR_NUM_COLS
Mode
READ/WRITE
Description
Number of columns being loaded in the table.
Attribute Data Type
ub2 */ub2 *

OCI_ATTR_NUM_ROWS
Mode
READ/WRITE

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Description
Read: The number of rows loaded so far.
Write: The number of rows to be allocated for the direct path and the direct path
function column arrays.
Attribute Data Type
ub2 */ub2 *

OCI_ATTR_SCHEMA_NAME
Mode
READ/WRITE
Description
Name of the schema where the table being loaded resides. If not specified, the
schema defaults to that of the connected user.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_SUB_NAME
Mode
READ/WRITE
Description
Name of the partition or subpartition to be loaded. If not specified, the entire table is
loaded. The name must be a valid partition or subpartition name that belongs to the
table.
Attribute Data Type
oratext **/oratext *

A.21.2 Direct Path Function Context Handle (OCIDirPathFuncCtx)
Attributes
Lists and describes direct path function context handle (OCIDirPathFuncCtx)
attributes.
For further explanations of these attributes, see Direct Path Function Context and
Attributes.
OCI_ATTR_DIRPATH_EXPR_TYPE
Mode
READ/WRITE
Description
Indicates the type of expression specified in OCI_ATTR_NAME in the function context of a
nonscalar column.
Valid values are:
•

OCI_DIRPATH_EXPR_OBJ_CONSTR (the object type name of a column object)

•

OCI_DIRPATH_EXPR_REF_TBLNAME (table name of a reference object)

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•

OCI_DIRPATH_EXPR_SQL (a SQL string to derive the column value)

Attribute Data Type
ub1 */ub1 *

OCI_ATTR_LIST_COLUMNS
Mode
READ
Description
Returns the handle to the parameter descriptor for the column list associated with the
direct path function context. The column list parameter descriptor can be retrieved
after the number of columns (number of attributes or arguments associated with the
nonscalar column) is set with the OCI_ATTR_NUM_COLS attribute.

See Also:
About Accessing Column Parameter Attributes
Attribute Data Type
OCIParam**

OCI_ATTR_NAME
Mode
READ/WRITE
Description
The object type name if the function context is describing a column object, a SQL
function if the function context is describing a SQL string, or a reference table name if
the function context is describing a REF column.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_NUM_COLS
Mode
READ/WRITE
Description
The number of the object attributes to load if the column is a column object, or the
number of arguments to process if the column is a SQL string or a REF column. This
parameter must be set before the column list can be retrieved.
Attribute Data Type
ub2 */ub2 *

OCI_ATTR_NUM_ROWS
Mode
READ

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Description
The number of rows loaded so far.
Attribute Data Type
ub4 *

A.21.3 Direct Path Function Column Array Handle
(OCIDirPathColArray) Attributes
Lists and describes direct path function column array handle (OCIDirPathColArray)
attributes.
The following attributes are used for the direct path function column array handle.
OCI_ATTR_COL_COUNT
Mode
READ
Description
Last column of the last row processed.
Attribute Data Type
ub2 *

OCI_ATTR_NUM_COLS
Mode
READ
Description
Column dimension of the column array.
Attribute Data Type
ub2 *

OCI_ATTR_NUM_ROWS
Mode
READ
Description
Row dimension of the column array.
Attribute Data Type
ub4 *

OCI_ATTR_ROW_COUNT
Mode
READ
Description
Number of rows successfully converted in the last call to
OCIDirPathColArrayToStream().

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Attribute Data Type
ub4 *

A.21.4 Direct Path Stream Handle (OCIDirPathStream) Attributes
Lists and describes direct path stream handle (OCIDirPathStream) attributes.
The following attributes are used for the direct path stream handle.
OCI_ATTR_BUF_ADDR
Mode
READ
Description
Buffer address of the beginning of the stream data.
Attribute Data Type
ub1 **

OCI_ATTR_BUF_SIZE
Mode
READ
Description
Size of the stream data in bytes.
Attribute Data Type
ub4 *

OCI_ATTR_ROW_COUNT
Mode
READ
Description
Number of rows successfully loaded by the last OCIDirPathLoadStream() call.
Attribute Data Type
ub4 *

OCI_ATTR_STREAM_OFFSET
Mode
READ
Description
Offset into the stream buffer of the last processed row.
Attribute Data Type
ub4 *

A.21.5 Direct Path Column Parameter Attributes
Describes how direct path column parameter attributes are used.

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Direct Path Loading Handle Attributes

The application specifies which columns are to be loaded, and the external format of
the data by setting attributes on each column parameter descriptor. The column
parameter descriptors are obtained as parameters of the column parameter list by
OCIParamGet(). The column parameter list of the table is obtained from the
OCI_ATTR_LIST_COLUMNS attribute of the direct path context. If a column is nonscalar,
then its column parameter list is obtained from the OCI_ATTR_LIST_COLUMNS attribute of
its direct path function context.
Note that all parameters are 1-based.

A.21.5.1 About Accessing Column Parameter Attributes
Lists and describes direct path column parameter attributes.
The following code example illustrates the use of the direct path column parameter
attributes for scalar columns. Before the attributes are accessed, you must first set the
number of columns to be loaded and get the column parameter list from the
OCI_ATTR_LIST_COLUMNS attribute.

See Also:
Direct Path Load Examples for Scalar Columns for the data structures
defined in the listings

...
/* set number of columns to be loaded */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)dpctx, (ub4)OCI_HTYPE_DIRPATH_CTX,
(void *)&tblp->ncol_tbl,
(ub4)0, (ub4)OCI_ATTR_NUM_COLS, ctlp->errhp_ctl));
/* get the column parameter list */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrGet((void *)dpctx, OCI_HTYPE_DIRPATH_CTX,
(void *)&ctlp->colLstDesc_ctl, (ub4 *)0,
OCI_ATTR_LIST_COLUMNS, ctlp->errhp_ctl));

Now you can set the parameter attributes.
/* set the attributes of each column by getting a parameter handle on each
* column, then setting attributes on the parameter handle for the column.
* Note that positions within a column list descriptor are 1-based. */
for (i = 0, pos = 1, colp = tblp->col_tbl, fldp = tblp->fld_tbl;
i < tblp->ncol_tbl;
i++, pos++, colp++, fldp++)
{
/* get parameter handle on the column */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIParamGet((const void *)ctlp->colLstDesc_ctl,
(ub4)OCI_DTYPE_PARAM, ctlp->errhp_ctl,
(void **)&colDesc, pos));
colp->id_col = i;

/* position in column array */

/* set external attributes on the column */

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/* column name */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)colp->name_col,
(ub4)strlen((const char *)colp->name_col),
(ub4)OCI_ATTR_NAME, ctlp->errhp_ctl));
/* column type */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)&colp->exttyp_col, (ub4)0,
(ub4)OCI_ATTR_DATA_TYPE, ctlp->errhp_ctl));
/* max data size */
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)&fldp->maxlen_fld, (ub4)0,
(ub4)OCI_ATTR_DATA_SIZE, ctlp->errhp_ctl));
if (colp->datemask_col)
/* set column (input field) date mask */
{
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)colp->datemask_col,
(ub4)strlen((const char *)colp->datemask_col),
(ub4)OCI_ATTR_DATEFORMAT, ctlp->errhp_ctl));
}
if (colp->prec_col)
{
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)&colp->prec_col, (ub4)0,
(ub4)OCI_ATTR_PRECISION, ctlp->errhp_ctl));
}
if (colp->scale_col)
{
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)&colp->scale_col, (ub4)0,
(ub4)OCI_ATTR_SCALE, ctlp->errhp_ctl));
}
if (colp->csid_col)
{
OCI_CHECK(ctlp->errhp_ctl, OCI_HTYPE_ERROR, ociret, ctlp,
OCIAttrSet((void *)colDesc, (ub4)OCI_DTYPE_PARAM,
(void *)&colp->csid_col, (ub4)0,
(ub4)OCI_ATTR_CHARSET_ID, ctlp->errhp_ctl));
}
/* free the parameter handle to the column descriptor */
OCI_CHECK((void *)0, 0, ociret, ctlp,
OCIDescriptorFree((void *)colDesc, OCI_DTYPE_PARAM));
}
...

OCI_ATTR_CHARSET_ID
Mode
READ/WRITE

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Description
Character set ID for character column. If not set, the character set ID defaults to the
character set ID set in the direct path context.
Attribute Data Type
ub2 */ub2 *

OCI_ATTR_DATA_SIZE
Mode
READ/WRITE
Description
Maximum size in bytes of the external data for the column. This can affect conversion
buffer sizes.
Attribute Data Type
ub4 */ub4 *

OCI_ATTR_DATA_TYPE
Mode
READ/WRITE
Description
Returns or sets the external data type of the column. Valid data types are:
•

SQLT_CHR

•

SQLT_DATE

•

SQLT_TIMESTAMP

•

SQLT_TIMESTAMP_TZ

•

SQLT_TIMESTAMP_LTZ

•

SQLT_INTERVAL_YM

•

SQLT_INTERVAL_DS

•

SQLT_CLOB

•

SQLT_BLOB

•

SQLT_INT

•

SQLT_UIN

•

SQLT_FLT

•

SQLT_PDN

•

SQLT_BIN

•

SQLT_NUM

•

SQLT_NTY

•

SQLT_REF

•

SQLT_VST

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Direct Path Loading Handle Attributes

•

SQLT_VNU

Attribute Data Type
ub2 */ub2 *

OCI_ATTR_DATEFORMAT
Mode
READ/WRITE
Description
Date conversion mask for the column. If not set, the date format defaults to the date
conversion mask set in the direct path context.
Attribute Data Type
oratext **/oratext *

OCI_ATTR_DIRPATH_OID
Mode
READ/WRITE
Description
Indicates that the column to load into is an object table's object ID column.
Attribute Data Type
ub1 */ub1 *

OCI_ATTR_DIRPATH_SID
Mode
READ/WRITE
Description
Indicates that the column to load into is a nested table's setid column.
Attribute Data Type
ub1 */ub1 *

OCI_ATTR_NAME
Mode
READ/WRITE
Description
Returns or sets the name of the column that is being loaded. Initialize both the column
name and the column name length to 0 before calling OCIAttrGet().
Attribute Data Type
oratext **/oratext *

OCI_ATTR_PRECISION
Mode
READ/WRITE

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Process Handle Attributes

Description
Returns or sets the precision.
Attribute Data Type
ub1 */ub1 * for explicit describes
sb2 */sb2 * for implicit describes
OCI_ATTR_SCALE
Mode
READ/WRITE
Description
Returns or sets the scale (number of digits to the right of the decimal point) for
conversions from packed and zoned decimal input data types.
Attribute Data Type
sb1 */sb1 *

A.22 Process Handle Attributes
Lists and describes process handle attributes.
The parameters for the shared system can be set and read using the OCIAttrSet() and
OCIAttrGet() calls. The handle type to be used is the process handle OCI_HTYPE_PROC.
The OCI_ATTR_MEMPOOL_APPNAME, OCI_ATTR_MEMPOOL_HOMENAME, and
OCI_ATTR_MEMPOOL_INSTNAME attributes specify the application, home, and instance
names that can be used together to map the process to the right shared pool area. If
these attributes are not provided, internal default values are used. The following are
valid settings of the attributes for specific behaviors:
•

Instance name, application name (unqualified): This allows only executables with a
specific name to attach to the same shared subsystem. For example, this allows
an OCI application named Office to connect to the same shared subsystem
regardless of the directory Office resides in.

•

Instance name, home name: This allows a set of executables in a specific home
directory to attach to the same instance of the shared subsystem. For example,
this allows all OCI applications residing in the ORACLE_HOME directory to use
the same shared subsystem.

•

Instance name, home name, application name (unqualified): This allows only a
specific executable to attach to a shared subsystem. For example, this allows one
application named Office in the ORACLE_HOME directory to attach to a given
shared subsystem.

See Also:
OCI_ATTR_SHARED_HEAPALLOC

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OCI_ATTR_MEMPOOL_APPNAME
Mode
READ/WRITE
Description
Executable name or fully qualified path name of the executable.
Attribute Data Type
oratext *

OCI_ATTR_MEMPOOL_HOMENAME
Mode
READ/WRITE
Description
Directory name where the executables that use the same shared subsystem instance
are located.
Attribute Data Type
oratext *

OCI_ATTR_MEMPOOL_INSTNAME
Mode
READ/WRITE
Description
Any user-defined name to identify an instance of the shared subsystem.
Attribute Data Type
oratext *

OCI_ATTR_MEMPOOL_SIZE
Mode
READ/WRITE
Description
Size of the shared pool in bytes. This attribute is set as follows:
ub4 plsz = 1000000;
OCIAttrSet((void *)0, (ub4) OCI_HTYPE_PROC,
(void *)&plsz, (ub4) 0, (ub4) OCI_ATTR_POOL_SIZE, 0);

Attribute Data Type
ub4 *

OCI_ATTR_PROC_MODE
Mode
READ

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Event Handle Attributes

Description
Returns all the currently set process modes. The value read contains the OR'ed value
of all the currently set OCI process modes. To determine if a specific mode is set, the
value should be AND'ed with that mode. For example:
ub4 mode;
boolean is_shared;
OCIAttrGet((void *)0, (ub4)OCI_HTYPE_PROC,
(void *) &mode, (ub4 *) 0,
(ub4)OCI_ATTR_PROC_MODE, 0);
is_shared = mode & OCI_SHARED;

Attribute Data Type
ub4 *

A.23 Event Handle Attributes
Lists and describes event handle attributes.
The OCIEvent handle encapsulates the attributes from the event payload. This handle
is implicitly allocated before the event callback is called.
The event callback obtains the attributes of an event using OCIAttrGet() with the
following attributes.

See Also:
HA Event Notification

OCI_ATTR_DBDOMAIN
Mode
READ
Description
When called with this attribute, OCIAttrGet() retrieves the name of the database
domain that has been affected by this event. This is also a server handle attribute.
Attribute Data Type
oratext **

OCI_ATTR_DBNAME
Mode
READ
Description
When called with this attribute, OCIAttrGet() retrieves the name of the database that
has been affected by this event. This is also a server handle attribute.
Attribute Data Type
oratext **

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Event Handle Attributes

OCI_ATTR_EVENTTYPE
Mode
READ
Description
The type of event that occurred, OCI_EVENTTYPE_HA.
Attribute Data Type
ub4 *

OCI_ATTR_HA_SOURCE
Mode
READ
Description
If the event type is OCI_EVENTTYPE_HA, get the source of the event with this attribute.
Valid values are:
•

OCI_HA_SOURCE_DATABASE

•

OCI_HA_SOURCE_NODE

•

OCI_HA_SOURCE_INSTANCE

•

OCI_HA_SOURCE_SERVICE

•

OCI_HA_SOURCE_SERVICE_MEMBER

•

OCI_HA_SOURCE_ASM_INSTANCE

•

OCI_HA_SOURCE_SERVICE_PRECONNECT

Attribute Data Type
ub4 *

OCI_ATTR_HA_SRVFIRST
Mode
READ
Description
When called with this attribute, OCIAttrGet() retrieves the first server handle in the list
of server handles affected by an Oracle Real Application Clusters (Oracle RAC) HA
DOWN event.
Attribute Data Type
OCIServer **

OCI_ATTR_HA_SRVNEXT
Mode
READ
Description
When called with this attribute OCIAttrGet() retrieves the next server handle in the list
of server handles affected by an Oracle RAC HA DOWN event.

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Event Handle Attributes

Attribute Data Type
OCIServer **

OCI_ATTR_HA_STATUS
Mode
READ
Description
Valid value is OCI_HA_STATUS_DOWN. Only DOWN events are subscribed to currently.
Attribute Data Type
ub4 *

OCI_ATTR_HA_TIMESTAMP
Mode
READ
Description
The time that the HA event occurred.
Attribute Data Type
OCIDateTime **

OCI_ATTR_HOSTNAME
Mode
READ
Description
When called with this attribute, OCIAttrGet() retrieves the name of the host that has
been affected by this event.
Attribute Data Type
oratext **

OCI_ATTR_INSTNAME
Mode
READ
Description
When called as an event handle attribute, OCIAttrGet() retrieves the name of the
instance that has been affected by this event. This is also a server handle attribute.
This attribute can also be used on service context to return the shard instance name
for a given connection. This attribute can be used to find the shard instance name out
of a shard instance descriptor that is filed by an OCIShardInstancesGet() call.
Attribute Data Type
oratext **

Example
The following example shows for a given connection (svchp) how to get the shard
instance name.

A-115

Appendix A

Event Handle Attributes

Oratext instanceName [OCI_INSTNAME_MAXLEN];
ub4
instanceNameLen;
OCIATTRGet(svchp,
OCI_HTYPE_SVCCTX,
instanceName,
(ub4 *) &instanceNameLen,
OCI_ATTR_INSTNAME,
errhp);

OCI_ATTR_INSTSTARTTIME
Mode
READ
Description
When called with this attribute, OCIAttrGet() retrieves the start time of the instance
that has been affected by this event. This is also a server handle attribute.
Attribute Data Type
OCIDateTime **

OCI_ATTR_SERVICENAME
Mode
READ
Description
When called with this attribute, OCIAttrGet() retrieves the name of the service that has
been affected by this event. The name length is ub4 *. This is also a server handle
attribute.
Attribute Data Type
oratext **

A-116

B
OCI Demonstration Programs
Lists example programs with sample code demonstrating the allocation and use of
OCI handles.
Oracle provides code examples illustrating the use of OCI calls. These programs are
provided for demonstration purposes, and are not guaranteed to run on all operating
systems.
You must install the demonstration programs as described in Oracle Database
Examples Installation Guide. The location, names, and availability of the programs
may vary on different operating systems. On a Linux or UNIX workstation, the
programs are installed in the $ORACLE_HOME/rdbms/demo directory. For Windows systems,
see Getting Started with OCI for Windows.
OCI header files that are required for OCI client application development on Linux or
UNIX platforms are in the $ORACLE_HOME/rdbms/public directory. The demo_rdbms.mk file is
in the $ORACLE_HOME/rdbms/demo directory and serves as an example makefile. On
Windows systems, make.bat is the analogous file in the samples directory. There are
instructions in the makefiles.
Unless you significantly modify the demo_rdbms.mk file, you are not affected by changes
you make as long the demo_rdbms.mk file includes the $ORACLE_HOME/rdbms/public
directory. Ensure that your highly customized makefiles have the $ORACLE_HOME/rdbms/
public directory in the INCLUDE path.
Development of new makefiles to build an OCI application or an external procedure
should consist of the customizing of the makefile provided by adding your own macros
to the link line. However, Oracle requires that you keep the macros provided in the
demo makefile, as it results in easier maintenance of your own makefiles.
When a specific header or SQL file is required by the application, these files are also
included as specified in the demonstration program file. Review the information in the
comments at the beginning of the demonstration programs for setups and hints on
running the programs.
Table B-1 lists the important demonstration programs and the OCI features that they
illustrate. Look for related files with the .sql extension.
Table B-1

OCI Demonstration Programs

Program Name

Features Illustrated

cdemo81.c

Using basic SQL processing with release 8 functionality

cdemo82.c

Performing basic processing of user-defined objects

cdemocor.c

Using complex object retrieval (COR) to improve performance

cdemodr1.c
cdemodr2.c
cdemodr3.c

Using INSERT, UPDATE, and DELETE statements, with RETURNING clause
used with basic data types, LOBs and REFs

cdemodsa.c

Describing information about a table

B-1

Appendix B

Table B-1

(Cont.) OCI Demonstration Programs

Program Name

Features Illustrated

cdemodsc.c

Describing information about an object type

cdemofo.c

Registering and operating application failover callbacks

cdemolb.c

Creating and inserting LOB data and then reading, writing, coping,
appending, and trimming the data

cdemolb2.c

Writing and reading of CLOB and BLOB columns with stream mode and
callback functions

cdemolbs.c

Writing and reading to LOBs with the LOB buffering system

cdemobj.c

Pinning and navigation of REF object

cdemocoll.c

Inserting and selecting of nested table and varray

cdemorid.c

Using INSERT, UPDATE, DELETE statements and fetches to get multiple
rowids in one round-trip

cdemoses.c

Using session switching and migration

cdemothr.c

Using the OCIThread package

cdemosyev.c

Registering predefined subscriptions and specifying a callback
function to be invoked for client notifications (for more information
about Advanced Queuing, see Oracle Database Advanced Queuing
User's Guide)

ociaqdemo00.c

Streams Advanced Queuing. Enqueues 100 messages

ociaqdemo01.c

Dequeues messages by blocking

ociaqdemo02.c

Listens for multiple agents

ociaqarrayenq.c

Array enqueue of 10 messages

ociaqarraydeq.c

Array dequeue of 10 messages

cdemodp.c,
cdemodp_lip.c

Loading data with the direct path load functions

cdemdpco.c

Loading a column object with the direct path load functions

cdemdpno.c

Loading a nested column object with the direct path load functions

cdemdpin.c

Loading derived type (inheritance) - direct path

cdemdpit.c

Loading an object table with inheritance - direct path

cdemdpro.c

Loading a reference with the direct path load functions

cdemdpss.c

Loading SQL strings with the direct path load functions

cdemoucb.c,
cdemoucbl.c

Using static and dynamic user callbacks

cdemoupk.c,
cdemoup1.c,
cdemoup2.c

Using dynamic user callbacks with multiple packages

cdemodt.c

Datetime and interval example. Demonstrates IN and OUT binds with
PL/SQL procedure or function

cdemosc.c

Scrollable cursor

cdemol2l.c

Accesses LOBs using the LONG API (Data Interface)

cdemoin1.c

Inheritance demo that modifies an inherited type in a table and
displays a record from the table

cdemoin2.c

Inheritance demo to do attribute substitutability

B-2

Appendix B

Table B-1

(Cont.) OCI Demonstration Programs

Program Name

Features Illustrated

cdemoin3.c

Inheritance demo that describes an object, inherited types, object
tables, and a sub-table

cdemoanydata1.c

Anydata demo. Inserts and selects rows to and from anydata table

cdemoanydata2.c

Anydata demo. Creates a type piecewise using
OCITypeBeginCreate() and then describes the new type created

cdemoqc.c

Query caching using SQL hints

cdemoqc2.c

Query caching using SQL hints and table annotation

cdemosp.c

Session pooling

cdemocp.c

Connection pooling

cdemocpproxy.c

Connection pooling with proxy functionality

cdemostc.c

Statement caching

cdemouni.c

Program for OCI UTF16 API

nchdemo1.c

Shows NCHAR implicit conversion feature and code point feature

B-3

C
OCI Function Server Round-Trips
This appendix provides information about server round-trips incurred during various
OCI calls.
This information can help programmers to determine the most efficient way to
accomplish a particular task in an application. A server round-trip is defined as the
trip from the client to the server and back to the client.
When using client-side SQL, OCI provides:
•

Enhanced array data manipulation language (DML) capability for arrays

•

Ability to associate a commit request with a run to reduce round-trips

•

Optimization for queries using transparent prefetch buffers to reduce round-trips

As is often the case, there are tradeoffs. For example, for queries the trade off is often
arraysize and prefetch size versus the number of underlying fetches.

See Also:
•

Using SQL Statements in OCI for an overview and more specific
information on tips to reduce server round-trips

•

OCI Array Interface to significantly reduce round-trips to the database
when you are updating or inserting a large volume of data

•

About Setting Prefetch Count to minimize server round-trips

.
This appendix contains these topics:
•

Relational Function Round-Trips

•

LOB Function Round-Trips

•

Object and Cache Function Round-Trips

•

Describe Operation Round-Trips

•

Data Type Mapping and Manipulation Function Round-Trips

•

Any Type and Data Function Round-Trips

•

Other Local Functions

C-1

Appendix C

Relational Function Round-Trips

C.1 Relational Function Round-Trips
Describes for each OCI relational function the number of server round-trips.
Table C-1 lists the number of server round-trips required by each OCI relational
function.
Table C-1

Server Round-Trips for Relational Operations

Function

Number of Server Round-Trips

OCIBreak()

1

OCIDBShutdown()

1

OCIDBStartup()

1

OCIEnvCreate()

0

OCIEnvInit()

0

OCIErrorGet()

0

OCIInitialize()

0

OCILdaToSvcCtx()

0

OCILogoff()

1

OCILogon()

1

OCILogon2()

Connection pool or session pool: same
as OCISessionGet()
Normal: 2 (depends on authentication
and TAF situation)

OCIPasswordChange()

1

OCIPing()

1

OCIReset()

0

OCIServerAttach()

1

OCIServerDetach()

1

OCIServerVersion()

1

OCISessionBegin()

1

OCISessionEnd()

1

OCISessionGet()

Session pool: 0 - increment of logins.
Connection pool: 1 to (1+ (increment *
logins)). Depends on cache hit: one for
the user session, optional increment for
primary sessions.
Normal: 1 login

OCISessionPoolCreate()

sessMin * logins

OCISessionPoolDestroy()

Sessions in cache * logoffs

OCISessionRelease()

Session pooling: 0, except when explicit
session destroys flag set
Normal: 1 login

OCIStmtExecute()

1

C-2

Appendix C

LOB Function Round-Trips

Table C-1

(Cont.) Server Round-Trips for Relational Operations

Function

Number of Server Round-Trips

OCIStmtFetch()

0 or 1

OCIStmtFetch2()

0 in prefetch, otherwise 1

OCIStmtGetPieceInfo()

1

OCIStmtPrepare()

0

OCIStmtPrepare2()

0

OCIStmtSetPieceInfo()

0

OCISvcCtxToLda()

0

OCITerminate()

1

OCITransCommit()

1

OCITransDetach()

1

OCITransForget()

1

OCITransPrepare()

1

OCItransRollback()

1

OCITransStart()

1

OCIUserCallbackGet()

0

OCIUserCallbackRegister()

0

C.2 LOB Function Round-Trips
Describes for each OCI LOB function the number of server round-trips.
Table C-2 lists the server round-trips incurred by the OCILob calls.

Note:
To minimize the number of round-trips, you can use the data interface for
LOBs. You can bind or define character data for a CLOB column or RAW data
for a BLOB column.

For calls whose number of round-trips is "0 or 1," if LOB buffering is on, and the
request can be satisfied in the client, no round-trips are incurred.
Table C-2

Server Round-Trips for OCILob Calls

Function

Number of Server Round-Trips

OCILobAppend()

1

OCILobArrayRead()

1

OCILobArraywrite()

1

OCILobAssign()

0

C-3

Appendix C

LOB Function Round-Trips

Table C-2

(Cont.) Server Round-Trips for OCILob Calls

Function

Number of Server Round-Trips

OCILobCharSetForm()

0

OCILobCharSetId()

0

OCILobClose()

1

OCILobCopy()

1

OCILobCopy2()

1

OCILobCreateTemporary()

1

OCILobDisableBuffering()

0

OCILobEnableBuffering()

0

OCILobErase()

1

OCILobErase2()

1

OCILobFileClose()

1

OCILobFileCloseAll()

1

OCILobFileExists()

1

OCILobFileGetName()

0

OCILobFileIsOpen()

1

OCILobFileOpen()

1

OCILobFileSetName()

0

OCILobFlushBuffer()

1 for each modified page in the buffer for this LOB

OCILobFreeTemporary()

1

OCILobGetChunkSize()

1

OCILobGetLength()

1

OCILobGetLength2()

1

OCILobGetStorageLimit()

1

OCILobIsEqual()

0

OCILobIsOpen()

1

OCILobIsTemporary()

0

OCILobLoadFromFile()

1

OCILobLoadFromFile2()

1

OCILobLocatorAssign()

1 round-trip if either the source or the destination
locator refers to a temporary LOB

OCILobLocatorIsInit()

0

OCILobOpen()

1

OCILobRead()

0 or 1

OCILobRead2()

0 or 1

OCILobTrim()

1

OCILobTrim2()

1

OCILobWrite()

0 or 1

C-4

Appendix C

Object and Cache Function Round-Trips

Table C-2

(Cont.) Server Round-Trips for OCILob Calls

Function

Number of Server Round-Trips

OCILobWrite2()

0 or 1

OCILobWriteAppend()

0 or 1

OCILobWriteAppend2()

0 or 1

See Also:
•

About Binding LOB Data for usage and examples for both INSERT and
UPDATE statements

•

About Defining LOB Data
for usage and examples of SELECT statements

C.3 Object and Cache Function Round-Trips
Describes for each OCI object and cache function the number of server round-trips.
Table C-3 lists the number of server round-trips required for the object and cache
functions. These values assume the cache is in a warm state, meaning that the type
descriptor objects required by the application have been loaded.
Table C-3

Server Round-Trips for Object and Cache Functions

Function

Number of Server Round-Trips

OCICacheFlush()

1

OCICacheFree()

0

OCICacheRefresh()

1

OCICacheUnmark()

0

OCICacheUnpin()

0

OCIObjectArrayPin()

1

OCIObjectCopy()

0

OCIObjectExists()

0

OCIObjectFlush()

1

OCIObjectFree()

0

OCIObjectGetInd()

0

OCIObjectGetObjectRef()

0

OCIObjectGetTypeRef()

0

OCIObjectIsDirty()

0

OCIObjectIsLocked()

0

OCIObjectLock()

1

C-5

Appendix C

Describe Operation Round-Trips

Table C-3

(Cont.) Server Round-Trips for Object and Cache Functions

Function

Number of Server Round-Trips

OCIObjectMarkDelete()

0

OCIObjectMarkDeleteByRef()

0

OCIObjectMarkUpdate()

0

OCIObjectNew()

0

OCIObjectPin()

1; 0 if the desired object is already in cache

OCIObjectPinCountReset()

0

OCIObjectPinTable()

1

OCIObjectRefresh()

1

OCIObjectUnmark()

0

OCIObjectUnmarkByRef()

0

OCIObjectUnpin()

0

C.4 Describe Operation Round-Trips
Describes for each OCI operation function the number of server round-trips.
Table C-4 lists the number of server round-trips required by OCIDescribeAny(),
OCIAttrGet(), and OCIParamGet().
Table C-4

Server Round-Trips for Describe Operations

Function

Number of Server Round-Trips

OCIAttrGet()

2 round-trips to describe a type if the type objects are not in the
object cache
1 round-trip for each collection element, or each type attribute,
method, or method argument descriptor. 1 more round-trip if using
OCI_ATTR_TYPE_NAME, or OCI_ATTR_SCHEMA_NAME on the collection
element, type attribute, or method argument.
0 if all the type objects to be described are already in the object
cache following the first OCIAttrGet() call.

OCIDescribeAny()

1 round-trip to get the REF of the type descriptor object

OCIParamGet()

0

C.5 Data Type Mapping and Manipulation Function RoundTrips
Describes for each OCI data type mapping and manipulation function the number of
server round-trips.
Table C-5 lists the number of round-trips for the data type mapping and manipulation
functions. The asterisks in the table indicate that all functions with a particular prefix

C-6

Appendix C

Any Type and Data Function Round-Trips

incur the same number of server round-trips. For example, OCINumberAdd(),
OCINumberPower(), and OCINumberFromText() all incur zero server round-trips.
Table C-5

Server Round-Trips for Data Type Manipulation Functions

Function

Number of Server Round-Trips

OCIColl*()

0; 1 if the collection is not loaded in the cache

OCIDate*()

0

OCIIter*()

0; 1 if the collection is not loaded in the cache

OCINumber*()

0

OCIRaw*()

0

OCIRef*()

0

OCIString*()

0

OCITable*()

0; 1 if the nested table is not loaded in the cache

C.6 Any Type and Data Function Round-Trips
Describes for each OCI Any Type and Data function the number of server round-trips.
Table C-6 lists the number of server round-trips required by Any Type and Data
functions. The functions not listed do not generate any round-trips.
Table C-6

Server Round-Trips for Any Type and Data Functions

Function

Number of Server Round-Trips

OCIAnyDataAttrGet()

0; 1 if the type information is not loaded in the cache

OCIAnyDataAttrSet()

0; 1 if the type information is not loaded in the cache

OCIAnyDataCollGetElem()

0; 1 if the type information is not loaded in the cache

C.7 Other Local Functions
Describes for each OCI other local function the number of server round-trips.
Table C-7 lists the functions that are local and do not require a server round-trip.
Table C-7

Locally Processed Functions

Local Function Name

Notes

OCIAttrGet()

When describing an object type, this call makes
one round-trip to fetch the type descriptor object.

OCIAttrSet()
OCIBindArrayOfStruct()
OCIDefineArrayOfStruct()
OCIBindByName()
OCIBindByPos()

C-7

Appendix C

Other Local Functions

Table C-7

(Cont.) Locally Processed Functions

Local Function Name

Notes

OCIBindDynamic()
OCIBindObject()
OCIDefineByPos()
OCIDefineDynamic()
OCIDefineObject()
OCIDescriptorAlloc()
OCIDescriptorFree()
OCIEnvCreate()
OCIEnvInit()
OCIErrorGet()
OCIHandleAlloc()
OCIHandleFree()
OCILdaToSvcCtx()
OCIStmtGetBindInfo()
OCIStmtPrepare()
OCIStmtRelease()
OCIStmtPrepare2()
OCISvcCtxToLda()

C-8

D
Getting Started with OCI for Windows
How to get started with OCI for Windows.
This appendix describes only the features of OCI that apply to the Windows 2003,
Windows 2000, and Windows XP operating systems. Windows NT is no longer
supported.
This chapter contains these topics:
•

What Is Included in the OCI Package for Windows?

•

Oracle Directory Structure for Windows

•

Sample OCI Programs for Windows

•

About Compiling OCI Applications for Windows

•

About Linking OCI Applications for Windows

•

About Running OCI Applications for Windows

•

Oracle XA Library

•

About Using the Object Type Translator for Windows

D.1 What Is Included in the OCI Package for Windows?
The OCI for Windows package includes the additional libraries required for linking your
OCI programs.
The Oracle Call Interface for Windows package includes:
•

Oracle Call Interface (OCI)

•

Required Support Files (RSFs)

•

Oracle Universal Installer

•

Header files for compiling OCI applications

•

Library files for linking OCI applications

•

Sample programs for demonstrating how to build OCI applications

See Also:
About Oracle Instant Client for a simplified OCI installation option

D-1

Appendix D

Oracle Directory Structure for Windows

D.2 Oracle Directory Structure for Windows
OCI is included in the default Oracle Database installation.
When you install Oracle Database, Oracle Universal Installer creates the OCI files in
the oci, bin, and precomp directories under the ORACLE_BASE\ORACLE_HOME directory.
These files include the library files needed to link and run OCI applications, and link
with other Oracle for Microsoft Windows products, such as Oracle Forms.
The ORACLE_BASE\ORACLE_HOME directory contains the following directories described in
Table D-1 that are relevant to OCI.
Table D-1

ORACLE_HOME Directories and Contents

Directory Name

Contents

\bin

Executable and help files

\oci

Oracle Call Interface directory for Windows files

\oci\include

Header files, such as oci.h and ociap.h

\oci\samples

Sample programs

\precomp\admin\ottcfg.cfg

Object Type Translator utility and default configuration file

D.3 Sample OCI Programs for Windows
Where sample program files and corresponding project files are copied when you
install OCI.
When OCI is installed, a set of sample programs and their corresponding project files
are copied to the ORACLE_BASE\ORACLE_HOME\oci\samples subdirectory. Oracle
recommends that you build and run these sample programs to verify that OCI has
been successfully installed and to familiarize yourself with the steps involved in
developing OCI applications.
To build a sample, run a batch file(make.bat)at the command prompt. For example, to
build the cdemo1.c sample, enter the following command in the directory samples:
C:> make cdemo1

After you finish using these sample programs, you can delete them if you choose.
The ociucb.c program should be compiled using ociucb.bat. This batch file creates a
DLL and places it in the ORACLE_BASE\ORACLE_HOME\bin directory. To load user callback
functions, set the environment registry variable ORA_OCI_UCBPKG to OCIUCB.

D.4 About Compiling OCI Applications for Windows
When you compile an OCI application, you must include the appropriate OCI header
files.
The header files are located in the \ORACLE_BASE\ORACLE_HOME\oci\include directory.

D-2

Appendix D

About Linking OCI Applications for Windows

For Microsoft Visual C++, specify \ORACLE_BASE\ORACLE_HOME\oci\lib\msvc in the
libraries section of the Option dialog box. For the Borland compiler, specify
\ORACLE_BASE\ORACLE_HOME\oci\lib\bc.
For example, if you are using Microsoft Visual C++ 8.0, you must put in the
appropriate path, \oracle\db_1\oci\include, in the Directories page of the Options
dialog in the Tools menu.

Note:
The only Microsoft Visual C++ releases supported for the current OCI
release are 7.1 or later.

See Also:
Your compiler's documentation for specific information about compiling your
application and special compiler options

D.5 About Linking OCI Applications for Windows
The OCI calls are implemented in dynamic-link libraries (DLLs) that Oracle provides.
The DLLs are located in the ORACLE_BASE\ORACLE_HOME\bin directory and are part of the
Required Support Files (RSFs).
Oracle only provides the oci.lib import library for use with the Microsoft compiler.
Borland compiler is also supported by Oracle for use with OCI. Oracle recommends
that applications must always link with oci.lib to avoid relinking or compilation with
every release.
When using oci.lib with the Microsoft compiler, you do not have to indicate any
special link options.
This section includes the following topics:
•

oci.lib

•

Client DLL Loading When Using Load Library()

D.5.1 oci.lib
Why you need applications linked with oci.lib.
Oracle recommends that applications be linked with oci.lib, which takes care of
loading the correct versions of the Oracle DLLs.

D.5.2 Client DLL Loading When Using Load Library()
How directories are searched when using the LoadLibrary.

D-3

Appendix D

About Running OCI Applications for Windows

The following directories are searched in this order by the LoadLibrary() function for
client DLL loading:
•

Directory from which the application is loaded or the directory where oci.dll is
located

•

Current directory

•

Windows:
–

The 32-bit Windows system directory (system32). Use the
GetWindowsDirectory() function of the Windows API to obtain the path of this
directory.

–
•

The 16-bit Windows directory (system). There is no Win32 function that
obtains the path of this directory, but it is searched.

Directories that are listed in the PATH environment variable

D.6 About Running OCI Applications for Windows
What’s needed to tun an OCI applications for Windows.
To run an OCI application, ensure that the entire corresponding set of Required
Support Files (RSFs) is installed on the computer that is running your OCI application.

D.7 Oracle XA Library
The XA application programming interface (API) is typically used to enable an Oracle
Database to interact with a transaction processing (TP) monitor, such as:
•

Oracle Tuxedo

•

IBM Transarc Encina

•

IBM CICS

You can also use TP monitor statements in your client programs. The use of the XA
API is supported from OCI.
The Oracle XA Library is automatically installed as part of Oracle Database Enterprise
Edition. Table D-2 lists the components created in your Oracle home directory. The
oci.lib import library contains the XA exports.
Table D-2

Oracle XA Components

Component

Location

xa.h

ORACLE_BASE\ORACLE_HOME\oci\include

This section includes the following topics:
•

About Compiling and Linking an OCI Program with the Oracle XA Library

•

About Using XA Dynamic Registration

•

XA and TP Monitor Information

D-4

Appendix D

Oracle XA Library

D.7.1 About Compiling and Linking an OCI Program with the Oracle
XA Library
How to compile and link an OCI program with the Oracle XA Library.
To compile and link an OCI program with the Oracle XA Library:
1.

Compile program.c by using Microsoft Visual C++ or the Borland compiler, making
sure to include ORACLE_BASE\ORACLE_HOME\rdbms\xa in your path.

2.

Link program.obj with the libraries shown in Table D-3:
Table D-3

Link Libraries

Library

Location

oraxa12.lib

ORACLE_BASE\ORACLE_HOME\rdbms\xa

oci.lib

ORACLE_BASE\ORACLE_HOME\oci\lib\msvc or,
ORACLE_BASE\ORACLE_HOME\oci\lib\bc

3.

Run program.exe.

D.7.2 About Using XA Dynamic Registration
The database supports the use of XA dynamic registration.
XA dynamic registration improves the performance of applications interacting with XAcompliant TP monitors. For TP monitors to use XA dynamic registration with an Oracle
Database on Windows, you must add either an environmental variable or a registry
variable to the Windows systems on which your TP monitor is running. See either of
the following sections for instructions:
•

Adding an Environmental Variable for the Current Session

•

About Adding a Registry Variable for All Sessions

•

Adding a Registry Variable:

D.7.2.1 Adding an Environmental Variable for the Current Session
Adding an environmental variable at the command prompt affects only the current
session.
To Add an Environmental Variable:
From the computer where your TP monitor is installed, enter the following at the
command prompt:
C:\> set ORA_XA_REG_DLL = vendor.dll

In this example, vendor.dll is the TP monitor DLL provided by your vendor.

D.7.2.2 About Adding a Registry Variable for All Sessions
Adding a registry variable affects all sessions on your Windows system.

D-5

Appendix D

About Using the Object Type Translator for Windows

This is useful for computers where only one TP monitor is running.

D.7.2.3 Adding a Registry Variable:
To add a registry variable for the TP monitor provided by your vendor, follow these
steps.
1.

Go to the computer where your TP monitor is installed.

2.

Enter the following at the command prompt:
C:\> regedt32

The Registry Editor window appears.
3.

Go to HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\HOMEID.

4.

Select the Add Value in the Edit menu. The Add Value dialog box appears.

5.

Enter ORA_XA_REG_DLL in the Value Name text box.

6.

Select REG_EXPAND_SZ from the Datatype list.

7.

Click OK. The String Editor dialog box appears.

8.

Enter vendor.dll in the String field, where vendor.dll is the TP monitor DLL
provided by your vendor.

9.

Click OK. The Registry Editor adds the parameter.

10. Select Exit from the Registry menu.

The registry exits.

D.7.3 XA and TP Monitor Information
See the Distributed TP: The XA Specification and other specific TP monitor and XA
information.
Distributed TP: The XA Specification (C193) published by the Open Group at the web
site: Distributed TP: The XA Specification

See Also:
•

Oracle Database Development Guide, the topic about developing
applications with Oracle XA, for more information about the Oracle XA
Library and using XA dynamic registration

•

Oracle Tuxedo for more information

D.8 About Using the Object Type Translator for Windows
To take advantage of objects, run the Object Type Translator (OTT) against the
database to generate a header file that includes the C structs.
For example, if a PERSON type has been created in the database, OTT can generate a C
struct with elements corresponding to the attributes of PERSON. In addition, a null

D-6

Appendix D

About Using the Object Type Translator for Windows

indicator struct is created that represents null information for an instance of the C
struct.
The intype file tells OTT which object types should be translated. This file also controls
the naming of the generated structs.

Note:
The INTYPE File Assistant is not available, starting with Oracle Database
10g Release 1.

Note that the CASE specification inside the intype files, such as CASE=LOWER, applies only
to C identifiers that are not specifically listed, either through a TYPE or TRANSLATE
statement in the intype file. It is important to provide the type name with the
appropriate cases, such as TYPE Person and Type PeRsOn, in the intype file.
OTT on Windows can be invoked from the command line. A configuration file can also
be named on the command line. For Windows, the configuration file is ottcfg.cfg,
located in ORACLE_BASE\ORACLE_HOME\precomp\admin.

D-7

E
Deprecated OCI Features and Functions
Deprecated OCI features and functions are those that may become obsolete in a
future release. Replacement OCI functions are mentioned where applicable.
Beginning with Oracle Database release 18c, version 18.1, the result set descriptor
OCI_DTYPE_RSET.
OCI release 7.3 API beginning with Oracle Database 12c Release 1 (12.1).
Table E-1 lists the OCI functions that were deprecated in releases previous to Oracle
11g R2 (11.2) unless otherwise noted. In a future release, these functions may
become obsolete.
Table E-1

Deprecated OCI Functions

Function Group Deprecated Functions
Initialize

OCIEnvInit(), OCIInitialize()

Statement

OCIStmtFetch()
Beginning with Oracle Database 12c Release 2 (12.2): OCIStmtPrepare()

Lob

OCILobCopy(), OCILobErase(), OCILobGetLength(),
OCILobLoadFromFile(), OCILobRead(), OCILobTrim(), OCILobWrite(),
OCILobWriteAppend()
Beginning with Oracle Database 12c Release 2 (12.2):
OCILobDisableBuffering(),OCILobEnableBuffering(), OCILobFlushBuffer()

Streams
Advanced
Queuing
functions

OCIAQListen()

This section includes the following topics:
•

Deprecated Initialize Functions

•

Deprecated Statement Functions

•

Deprecated Lob Functions

•

Deprecated Streams Advanced Queuing Functions

E.1 Deprecated Initialize Functions
Describes the deprecated initialize functions.
Table E-2 lists the deprecated Initialize functions that are described in this section.

E-1

Appendix E

Deprecated Initialize Functions

Table E-2

Deprecated Initialize Functions

Function

Purpose

OCIEnvInit()

Initialize an environment handle.

OCIInitialize()

Initialize OCI process environment.

E.1.1 OCIEnvInit()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Allocates and initializes an OCI environment handle. This function is deprecated.
Syntax
sword OCIEnvInit ( OCIEnv
ub4
size_t
void

**envhpp,
mode,
xtramemsz,
**usrmempp );

Parameters
envhpp (OUT)
A pointer to a handle to the environment.
mode (IN)
Specifies initialization of an environment mode. Valid modes are:
•

OCI_DEFAULT

•

OCI_ENV_NO_UCB

In OCI_DEFAULT mode, the OCI library always mutexes handles.
The OCI_ENV_NO_UCB mode is used to suppress the calling of the dynamic callback
routine OCIEnvCallback() at environment initialization time. The default behavior is to
allow such a call to be made.

See Also:
Dynamic Callback Registrations

xtramemsz (IN)
Specifies the amount of user memory to be allocated for the duration of the
environment.
usrmempp (OUT)
Returns a pointer to the user memory of size xtramemsz allocated by the call for the
user for the duration of the environment.

E-2

Appendix E

Deprecated Initialize Functions

Comments

Note:
Use OCIEnvCreate() instead of the OCIInitialize() and OCIEnvInit() calls.
OCIInitialize() and OCIEnvInit() calls are supported for backward
compatibility.

This call allocates and initializes an OCI environment handle. No changes are made to
an initialized handle. If OCI_ERROR or OCI_SUCCESS_WITH_INFO is returned, you can use the
environment handle to obtain Oracle-specific errors and diagnostics.
This call is processed locally, without a server round-trip.
The environment handle can be freed using OCIHandleFree().
Related Topics
•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIHandleFree()
Explicitly deallocates a handle

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCITerminate()
Detaches the process from the shared memory subsystem and releases the
shared memory.

See Also:
User Memory Allocation for more information about the xtramemsz parameter
and user memory allocation

E.1.2 OCIInitialize()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Initializes the OCI process environment. This function is deprecated.
Syntax
sword OCIInitialize ( ub4
const void
const void

mode,
*ctxp,
*(*malocfp)
( void *ctxp,
size_t size ),

E-3

Appendix E

Deprecated Initialize Functions

const void

const void

*(*ralocfp)
( void *ctxp,
void *memptr,
size_t newsize ),
(*mfreefp)
( void *ctxp,
void *memptr ));

Parameters
mode (IN)
Specifies initialization of the mode. The valid modes are:
•

OCI_DEFAULT - Default mode.

•

OCI_THREADED - Threaded environment. In this mode, internal data structures not

exposed to the user are protected from concurrent accesses by multiple threads.
•

OCI_OBJECT - Uses object features.

•

OCI_EVENTS - Uses publish-subscribe notifications.

ctxp (IN)
User-defined context for the memory callback routines.
malocfp (IN)
User-defined memory allocation function. If mode is OCI_THREADED, this memory
allocation routine must be thread-safe.
ctxp (IN/OUT)
Context pointer for the user-defined memory allocation function.
size (IN)
Size of memory to be allocated by the user-defined memory allocation function.
ralocfp (IN)
User-defined memory reallocation function. If mode is OCI_THREADED, this memory
allocation routine must be thread-safe.
ctxp (IN/OUT)
Context pointer for the user-defined memory reallocation function.
memptr (IN/OUT)
Pointer to memory block.
newsize (IN)
New size of memory to be allocated.
mfreefp (IN)
User-defined memory free function. If mode is OCI_THREADED, this memory free routine
must be thread-safe.
ctxp (IN/OUT)
Context pointer for the user-defined memory free function.
memptr (IN/OUT)
Pointer to memory to be freed.

E-4

Appendix E

Deprecated Initialize Functions

Comments

Note:
Use OCIEnvCreate() instead of the deprecated OCIInitialize() call. The
OCIInitialize() call is supported for backward compatibility.

This call initializes the OCI process environment. OCIInitialize() must be invoked
before any other OCI call.
This function provides the ability for the application to define its own memory
management functions through callbacks. If the application has defined such functions
(that is, memory allocation, memory reallocation, memory free), they should be
registered using the callback parameters in this function.
These memory callbacks are optional. If the application passes NULL values for the
memory callbacks in this function, the default process memory allocation mechanism
is used.

See Also:
•

Overview of OCI Multithreaded Development for information about using
the OCI to write multithreaded applications

•

OCI Object-Relational Programming for information about OCI
programming with objects

Example
The following statement shows an example of how to call OCIInitialize() in both
threaded and object mode, with no user-defined memory functions:
OCIInitialize((ub4) OCI_THREADED | OCI_OBJECT, (void *)0,
(void * (*)()) 0, (void * (*)()) 0, (void (*)()) 0 );

Related Topics
•

OCIHandleAlloc()
Returns a pointer to an allocated and initialized handle.

•

OCIHandleFree()
Explicitly deallocates a handle

•

OCIEnvCreate()
Creates and initializes an environment handle for OCI functions to work under.

•

OCITerminate()
Detaches the process from the shared memory subsystem and releases the
shared memory.

E-5

Appendix E

Deprecated Statement Functions

E.2 Deprecated Statement Functions
Describes the deprecated statement functions.
Table E-3 lists the deprecated Statement functions that are described in this section.
Table E-3

Deprecated Statement Functions

Function

Purpose

OCIStmtFetch()

Fetch rows from a query.

OCIStmtPrepare()

Prepares a SQL or PL/SQL statement for execution.

E.2.1 OCIStmtFetch()
This function was deprecated in a release previous to Oracle 11g R2 (11.2).
Purpose
Fetches rows from a query. This function is deprecated. Use OCIStmtFetch2().
Syntax
sword OCIStmtFetch ( OCIStmt
OCIError
ub4
ub2
ub4

*stmtp,
*errhp,
nrows,
orientation,
mode );

Parameters
stmtp (IN)
A statement (application request) handle.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
nrows (IN)
Number of rows to be fetched from the current position.
orientation (IN)
Before release 9.0, the only acceptable value is OCI_FETCH_NEXT, which is also the
default value.
mode (IN)
Pass as OCI_DEFAULT.
Comments
The fetch call is a local call, if prefetched rows suffice. However, this is transparent to
the application.

E-6

Appendix E

Deprecated Statement Functions

If LOB columns are being read, LOB locators are fetched for subsequent LOB
operations to be performed on these locators. Prefetching is turned off if LONG columns
are involved.
This function can return OCI_NO_DATA on EOF and OCI_SUCCESS_WITH_INFO when one of
these errors occurs:
•

ORA-24344 - Success with compilation error

•

ORA-24345 - A truncation or NULL fetch error occurred

•

ORA-24347 - Warning of a NULL column in an aggregate function

If you call OCIStmtFetch() with the nrows parameter set to 0, this cancels the cursor.
Use OCI_ATTR_ROWS_FETCHED to find the number of rows that were successfully fetched
into the user's buffers in the last fetch call.
Related Topics
•

OCIStmtFetch2()
Fetches a row from the (scrollable) result set.

E.2.2 OCIStmtPrepare()
This function was deprecated beginning with Oracle Database 12c Release 2 (12.2).
Purpose
Prepares a SQL or PL/SQL statement for execution. This function is deprecated. Use
OCIStmtPrepare2().
Syntax
sword OCIStmtPrepare ( OCIStmt
OCIError
const OraText
ub4
ub4
ub4

*stmtp,
*errhp,
*stmt,
stmt_len,
language,
mode );

Parameters
stmtp (IN)
A statement handle associated with the statement to be executed. By default, it
contains the encoding setting in the environment handle from which it is derived. A
statement can be prepared in UTF-16 encoding only in a UTF-16 environment.
errhp (IN)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
stmt (IN)
SQL or PL/SQL statement to be executed. Must be a NULL-terminated string. That is,
the ending character is a number of NULL bytes, depending on the encoding. The
statement must be in the encoding specified by the charset parameter of a previous
call to OCIEnvNlsCreate().
Always cast the parameter to (text *). After a statement has been prepared in
UTF-16, the character set for the bind and define buffers default to UTF-16.

E-7

Appendix E

Deprecated Statement Functions

stmt_len (IN)
Length of the statement in characters or in number of bytes, depending on the
encoding. Must not be zero.
language (IN)
Specifies V7, or native syntax. Possible values are as follows:
•

OCI_V7_SYNTAX - V7 ORACLE parsing syntax.

•

OCI_NTV_SYNTAX - Syntax depends upon the version of the server.
OCI_FOREIGN_SYNTAX - Specifies the statement to be translated according to the SQL
translation profile set in the session.

mode (IN)
Similar to the mode in the OCIEnvCreate() call, but this one has higher priority because
it can override the "naturally" inherited mode setting.
The possible values are OCI_DEFAULT (default mode) or OCI_PREP2_IMPL_RESULTS_CLIENT.
The mode should be passed as OCI_PREP2_IMPL_RESULTS_CLIENT when this call is made
in an external procedure and implicit results need to be processed. See OCI Support
for Implicit Results for more details. The statement handle stmtp uses whatever is
specified by its parent environment handle.
Comments
An OCI application uses this call to prepare a SQL or PL/SQL statement for execution.
The OCIStmtPrepare() call defines an application request.
The mode parameter determines whether the statement content is encoded as UTF-16
or not. The statement length is in number of code points or in number of bytes,
depending on the encoding.
Although the statement handle inherits the encoding setting from the parent
environment handle, the mode for this call can also change the encoding setting for the
statement handle itself.
Data values for this statement initialized in subsequent bind calls are stored in a bind
handle that uses settings in this statement handle as the default.
This call does not create an association between this statement handle and any
particular server.
Before reexecuting a DDL statement, call this function a second time.
This call does not support Application Continuity and if this call is used, it returns the
following error: Error - ORA-25412: transaction replay disabled by call to
OCIStmtPrepare. Use the OCIStmtPrepare2() call to support the use of Application
Continuity in an HA infrastructure.
Related Topics
•

OCIStmtPrepare2()
Prepares a SQL or PL/SQL statement for execution.

E-8

Appendix E

Deprecated Lob Functions

See Also:
About Preparing Statements for more information about using this call

E.3 Deprecated Lob Functions
Describes the deprecated LOB functions.
Table E-4 lists the deprecated LOB functions that are described in this section.
Beginning with Oracle Database 12c Release 2 (12.2), most LOB functions including
some deprecated LOB functions as indicated in the following table support Application
Continuity (see When Application Continuity in OCI Can Fail Over for a complete list).
Table E-4

Deprecated LOB Functions

Function

Purpose

OCILobCopy()

Copy all or part of one LOB to
another. Supports Application
Continuity.

OCILobDisableBuffering()

Disables LOB buffering for the
input locator.

OCILobEnableBuffering()

Enables LOB buffering for the
input locator.

OCILobErase()

Erase a portion of a LOB.
Supports Application Continuity.

OCILobFlushBuffer()

Flushes or write s all buffers for
this LOB to the server.

OCILobGetLength()

Get length of a LOB.

OCILobLoadFromFile()

Load a LOB from a BFILE.
Supports Application Continuity.

OCILobRead()

Read a portion of a LOB.
Supports Application Continuity.

OCILobTrim()

Truncate a LOB. Supports
Application Continuity.

OCILobWrite()

Write into a LOB. Supports
Application Continuity.

OCILobWriteAppend()

Write data beginning at the end
of a LOB.

E.3.1 OCILobCopy()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Copies all or a portion of a LOB value into another LOB value. This function is
deprecated. Use OCILobCopy2().

E-9

Appendix E

Deprecated Lob Functions

Syntax
sword OCILobCopy ( OCISvcCtx
OCIError
OCILobLocator
OCILobLocator
ub4
ub4
ub4

*svchp,
*errhp,
*dst_locp,
*src_locp,
amount,
dst_offset,
src_offset );

Parameters
Related Topics
•

OCILobCopy2()
Copies all or a portion of a LOB value into another LOB value.

E.3.2 OCILobDisableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2 (12.2).
Purpose
Disables LOB buffering for the input locator. This function is deprecated.
Syntax
sword OCILobDisableBuffering ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() or diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator uniquely referencing the LOB.
Comments
Disables LOB buffering for the input internal LOB locator. The next time data is read
from or written to the LOB through the input locator, the LOB buffering subsystem is
not used. Note that this call does not implicitly flush the changes made in the buffering
subsystem. The user must explicitly call OCILobFlushBuffer() to do this.
OCILobDisableBuffering() throws an error when a remote locator is passed to it.

This function does not accept a BFILE locator.

E-10

Appendix E

Deprecated Lob Functions

Related Topics
•

OCILobEnableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

OCILobFlushBuffer()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

E.3.3 OCILobEnableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2 (12.2).
Purpose
Enables LOB buffering for the input locator. This function is deprecated.
Syntax
sword OCILobEnableBuffering ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp );

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator uniquely referencing the LOB.
Comments
Enables LOB buffering for the input internal LOB locator. The next time data is read
from or written to the LOB through the input locator, the LOB buffering subsystem is
used.
OCILobEnableBuffering() throws an error when a remote locator is passed to it.

If LOB buffering is enabled for a locator and that locator is passed to one of these
routines, an error is returned: OCILobAppend(), OCILobCopy() (deprecated),
OCILobCopy2(), OCILobErase() (deprecated), OCILobErase2(), OCILobGetLength()
(deprecated), OCILobGetLength2(), OCILobLoadFromFile() (deprecated),
OCILobLoadFromFile2(), OCILobTrim() (deprecated), OCILobTrim2(),
OCILobWriteAppend() (deprecated), or OCILobWriteAppend2().
This function does not accept a BFILE locator.

E-11

Appendix E

Deprecated Lob Functions

Related Topics
•

OCILobDisableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

OCILobWrite()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobRead()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobFlushBuffer()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCILobWriteAppend()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

E.3.4 OCILobErase()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Erases a specified portion of the internal LOB data starting at a specified offset. This
function is deprecated. Use OCILobErase2().
Syntax
sword OCILobErase ( OCISvcCtx
OCIError
OCILobLocator
ub4
ub4

*svchp,
*errhp,
*locp,
*amount,
offset );

Parameters
Related Topics
•

OCILobErase2()
Erases a specified portion of the internal LOB data starting at a specified offset.

E-12

Appendix E

Deprecated Lob Functions

E.3.5 OCILobFlushBuffer()
This function was deprecated beginning with Oracle Database 12c Release 2 (12.2).
Purpose
Flushes or write s all buffers for this LOB to the server. This function is deprecated.
Syntax
sword OCILobFlushBuffer ( OCISvcCtx
OCIError
OCILobLocator
ub4

*svchp,
*errhp,
*locp
flag );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal locator uniquely referencing the LOB.
flag (IN)
When this flag is set to OCI_LOB_BUFFER_FREE, the buffer resources for the LOB are
freed after the flush. See the Comments section.
Comments
Flushes to the server changes made to the buffering subsystem that are associated
with the LOB referenced by the input locator. This routine actually writes the data in
the buffer to the LOB in the database. LOB buffering must have been enabled for the
input LOB locator.
OCILobFlushBuffer() throws an error when a remote locator is passed to it.

The flush operation, by default, does not free the buffer resources for reallocation to
another buffered LOB operation. To free the buffer explicitly, you can set the flag
parameter to OCI_LOB_BUFFER_FREE.
If the client application intends to read the buffer value after the flush and knows in
advance that the current value in the buffer is the desired value, there is no need to
reread the data from the server.
The effects of freeing the buffer are mostly transparent to the user, except that the
next access to the same range in the LOB involves a round-trip to the server, and
there is an added cost for acquiring buffer resources and initializing the buffer with the
data read from the LOB. This option is intended for client environments that have low
on-board memory.

E-13

Appendix E

Deprecated Lob Functions

Related Topics
•

OCILobEnableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCIErrorGet()
Returns an error message and an Oracle Database error code.

•

OCILobWrite()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

•

OCILobRead()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

•

OCILobDisableBuffering()
This function was deprecated beginning with Oracle Database 12c Release 2
(12.2).

•

OCILobWriteAppend()
This function was deprecated in a release previous to Oracle Database 11g
Release 2 (11.2).

•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

E.3.6 OCILobGetLength()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Gets the length of a LOB. This function is deprecated. Use OCILobGetLength2().
Syntax
sword OCILobGetLength ( OCISvcCtx
OCIError
OCILobLocator
ub4

*svchp,
*errhp,
*locp,
*lenp );

Parameters
Related Topics
•

OCILobGetLength2()
Gets the length of a LOB. This function must be used for LOBs of size greater than
4 GB.

E-14

Appendix E

Deprecated Lob Functions

E.3.7 OCILobLoadFromFile()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Loads and copies all or a portion of the file into an internal LOB. This function is
deprecated. Use OCILobLoadFromFile2().
Syntax
sword OCILobLoadFromFile ( OCISvcCtx
OCIError
OCILobLocator
OCILobLocator
ub4
ub4
ub4

*svchp,
*errhp,
*dst_locp,
*src_locp,
amount,
dst_offset,
src_offset );

Parameters
Related Topics
•

OCILobLoadFromFile2()
Loads and copies all or a portion of the file into an internal LOB. This function must
be used for LOBs of size greater than 4 GB.

E.3.8 OCILobRead()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This function
is deprecated. Use OCILobRead2().
Syntax
sword OCILobRead ( OCISvcCtx
OCIError
OCILobLocator
ub4
ub4
void
ub4
void
OCICallbackLobRead

ub2
ub1

*svchp,
*errhp,
*locp,
*amtp,
offset,
*bufp,
bufl,
*ctxp,
(cbfp)
( void
const void
ub4
ub1
)
csid,
csfrm );

*ctxp,
*bufp,
len,
piece

E-15

Appendix E

Deprecated Lob Functions

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN)
A LOB or BFILE locator that uniquely references the LOB or BFILE. This locator must
have been a locator that was obtained from the server specified by svchp.
amtp (IN/OUT)
The value in amtp is the amount in either bytes or characters, as shown in Table E-5.
Table E-5

Characters or Bytes in amtp for OCILobRead()

LOB or BFILE

Input

Output with Fixed-Width
Client-Side Character
Set

Output with Varying-Width
Client-Side Character Set

BLOBs and BFILEs

bytes

bytes

bytes

CLOBs and NCLOBs

characters

characters

bytes 1

1

The input amount refers to the number of characters to be read from the server-side CLOB or NCLOB. The
output amount indicates how many bytes were read into the buffer bufp.

The parameter amtp is the total amount of data read if:
•

Data is not read in streamed mode (only one piece is read and there is no polling
or callback)

•

Data is read in streamed mode with a callback

The parameter amtp is the length of the last piece read if the data is read in streamed
mode using polling.
If the amount to be read is larger than the buffer length, it is assumed that the LOB is
being read in a streamed mode from the input offset until the end of the LOB, or until
the specified number of bytes have been read, whichever comes first. On input, if this
value is 0, then the data is read in streamed mode from the input offset until the end of
the LOB.
The streamed mode (implemented with either polling or callbacks) reads the LOB
value sequentially from the input offset.
If the data is read in pieces, the amtp parameter always contains the length of the piece
just read.
If a callback function is defined, then this callback function is invoked each time bufl
bytes are read off the pipe. Each piece is written into bufp.
If the callback function is not defined, then the OCI_NEED_DATA error code is returned.
The application must call OCILobRead() over and over again to read more pieces of the
LOB until the OCI_NEED_DATA error code is not returned. The buffer pointer and the

E-16

Appendix E

Deprecated Lob Functions

length can be different in each call if the pieces are being read into different sizes and
locations.
offset (IN)
On input, this is the absolute offset from the beginning of the LOB value. For
character LOBs (CLOBs, NCLOBs) it is the number of characters from the beginning of
the LOB, for binary LOBs or BFILEs it is the number of bytes. The first position is 1.
If you use streaming (by polling or a callback), specify the offset in the first call; in
subsequent polling calls, the offset parameter is ignored. When you use a callback,
there is no offset parameter.
bufp (IN/OUT)
The pointer to a buffer into which the piece is read. The length of the allocated
memory is assumed to be bufl.
bufl (IN)
The length of the buffer in octets. This value differs from the amtp value for CLOBs and
for NCLOBs (csfrm=SQLCS_NCHAR) when the amtp parameter is specified in terms of
characters, and the bufl parameter is specified in terms of bytes.
ctxp (IN)
The context pointer for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece. If this is NULL, then
OCI_NEED_DATA is returned for each piece.
The callback function must return OCI_CONTINUE for the read to continue. If any other
error code is returned, the LOB read is terminated.
ctxp (IN)
The context for the callback function. Can be NULL.
bufp (IN/OUT)
A buffer pointer for the piece.
len (IN)
The length in bytes of the current piece in bufp.
piece (IN)
Which piece: OCI_FIRST_PIECE, OCI_NEXT_PIECE, or OCI_LAST_PIECE.
csid (IN)
The character set ID of the buffer data. If this value is 0, then csid is set to the client's
NLS_LANG or NLS_CHAR value, depending on the value of csfrm. It is never assumed to be
the server's character set, unless the server and client have the same settings.
csfrm (IN)
The character set form of the buffer data. The csfrm parameter must be consistent
with the type of the LOB.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT. If csfrm is not specified, the default is assumed.

E-17

Appendix E

Deprecated Lob Functions

Comments
Reads a portion of a LOB or BFILE as specified by the call into a buffer. It is an error to
try to read from a NULL LOB or BFILE.

Note:
When you read or write LOBs, specify a character set form (csfrm) that
matches the form of the locator itself.

For BFILEs, the operating system file must exist on the server, and it must have been
opened by OCILobFileOpen() or OCILobOpen() using the input locator. Oracle
Database must have permission to read the operating system file, and the user must
have read permission on the directory object.
When you use the polling mode for OCILobRead(), the first call must specify values for
offset and amtp, but on subsequent polling calls to OCILobRead(), you need not specify
these values.
If the LOB is a BLOB, the csid and csfrm parameters are ignored.

Note:
To terminate an OCILobRead() operation and free the statement handle, use
the OCIBreak() call.

The following apply to client-side varying-width character sets for CLOBs and NCLOBs:
•

When you use polling mode, be sure to specify the amtp and offset parameters
only in the first call to OCILobRead(). On subsequent polling calls, these parameters
are ignored.

•

When you use callbacks, the len parameter, which is input to the callback,
indicates how many bytes are filled in the buffer. Check the len parameter during
your callback processing because the entire buffer cannot be filled with data.

The following applies to client-side fixed-width character sets and server-side varyingwidth character sets for CLOBs and NCLOBs:
•

When reading a CLOB or NCLOB value, look at the amtp parameter after every call to
OCILobRead() to see how much of the buffer is filled. When the return value is in
characters (as when the client-side character set is fixed-width), then convert this
value to bytes and determine how much of the buffer is filled. When you use
callbacks, always check the len parameter to see how much of the buffer is filled.
This value is always in bytes.

To read data in UTF-16 format, set the csid parameter to OCI_UTF16ID. If the csid
parameter is set, it overrides the NLS_LANG environment variable.

E-18

Appendix E

Deprecated Lob Functions

Related Topics
•

OCILobRead2()
Reads a portion of a LOB or BFILE, as specified by the call, into a buffer. This
function must be used for LOBs of size greater than 4 GB.

See Also:
•

PL/SQL REF CURSORs and Nested Tables in OCI for additional
information about Unicode format

•

Oracle Database SecureFiles and Large Objects Developer's Guide for a
description of BFILEs

•

The demonstration programs included with your Oracle Database
installation for a code sample showing the use of LOB reads and writes.

•

OCI Demonstration Programs

•

Runtime Data Allocation and Piecewise Operations in OCI for general
information about piecewise OCI operations

•

Polling Mode Operations in OCI

E.3.9 OCILobTrim()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Truncates the LOB value to a shorter length. This function is deprecated. Use
OCILobTrim2().
Syntax
sword OCILobTrim ( OCISvcCtx
OCIError
OCILobLocator
ub4

*svchp,
*errhp,
*locp,
newlen );

Parameters
Related Topics
•

OCILobTrim2()
Truncates the LOB value to a shorter length. This function must be used for LOBs
of size greater than 4 GB.

E-19

Appendix E

Deprecated Lob Functions

E.3.10 OCILobWrite()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Writes a buffer into a LOB. This function is deprecated. Use OCILobWrite2().
Syntax
sword OCILobWrite ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp,
ub4
*amtp,
ub4
offset,
void
*bufp,
ub4
buflen,
ub1
piece,
void
*ctxp,
OCICallbackLobWrite
(cbfp)
(
void
*ctxp,
void
*bufp,
ub4
*lenp,
ub1
*piecep
)
ub2
csid,
ub1
csfrm );

Parameters
svchp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator that uniquely references the LOB. This locator must have
been a locator that was obtained from the server specified by svchp.
amtp (IN/OUT)
The value in amtp is the amount in either bytes or characters, as shown in Table E-6.
Table E-6

Characters or Bytes in amtp for OCILobWrite()

LOB or BFILE

Input with Fixed-Width
Client-Side Character Set

Input with Varying-Width
Client-Side Character Set

Output

BLOBs and BFILEs

bytes

bytes

bytes

CLOBs and NCLOBs
1

characters

bytes

1

characters

The input amount refers to the number of bytes of data that the user wants to write into the LOB and not
the number of bytes in the bufp, which is specified by buflen. If data is written in pieces, the amount of

E-20

Appendix E

Deprecated Lob Functions

bytes to write may be larger than the buflen. The output amount refers to the number of characters
written into the server-side CLOB or NCLOB.

This should always be a non-NULL pointer. If you want to specify write-until-end-of-file,
then you must declare a variable, set it equal to zero, and pass its address for this
parameter.
If the amount is specified on input, and the data is written in pieces, the parameter amtp
contains the total length of the pieces written at the end of the call (last piece written)
and is undefined in between. Note that it is different from the piecewise read case. An
error is returned if that amount is not sent to the server.
If amtp is zero, then streaming mode is assumed, and data is written until the user
specifies OCI_LAST_PIECE.
offset (IN)
On input, it is the absolute offset from the beginning of the LOB value. For character
LOBs, it is the number of characters from the beginning of the LOB; for binary LOBs,
it is the number of bytes. The first position is 1.
If you use streaming (by polling or a callback), specify the offset in the first call; in
subsequent polling calls, the offset parameter is ignored. When you use a callback,
there is no offset parameter.
bufp (IN)
The pointer to a buffer from which the piece is written. The length of the data in the
buffer is assumed to be the value passed in buflen. Even if the data is being written in
pieces using the polling method, bufp must contain the first piece of the LOB when
this call is invoked. If a callback is provided, bufp must not be used to provide data or
an error results.
buflen (IN)
The length, in bytes, of the data in the buffer. This value differs from the amtp value for
CLOBs and NCLOBs when the amtp parameter is specified in terms of characters, and the
buflen parameter is specified in terms of bytes.

Note:
This parameter assumes an 8-bit byte. If your operating system uses a
longer byte, you must adjust the value of buflen accordingly.
piece (IN)
Which piece of the buffer is being written. The default value for this parameter is
OCI_ONE_PIECE, indicating that the buffer is written in a single piece. The following other
values are also possible for piecewise or callback mode: OCI_FIRST_PIECE,
OCI_NEXT_PIECE, and OCI_LAST_PIECE.
ctxp (IN)
The context for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece in a piecewise write. If
this is NULL, the standard polling method is used.

E-21

Appendix E

Deprecated Lob Functions

The callback function must return OCI_CONTINUE for the write to continue. If any other
error code is returned, the LOB write is terminated. The callback takes the following
parameters:
ctxp (IN)
The context for the callback function. Can be NULL.
bufp (IN/OUT)
A buffer pointer for the piece. This is the same as the bufp passed as an input to the
OCILobWrite() routine.
lenp (IN/OUT)
The length (in bytes) of the data in the buffer (IN), and the length (in bytes) of the
current piece in bufp (OUT).
piecep (OUT)
Which piece: OCI_NEXT_PIECE or OCI_LAST_PIECE.
csid (IN)
The character set ID of the data in the buffer. If this value is 0, then csid is set to the
client's NLS_LANG or NLS_CHAR value, depending on the value of csfrm.
csfrm (IN)
The character set form of the buffer data. The csfrm parameter must be consistent
with the type of the LOB.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

The default value is SQLCS_IMPLICIT.
Comments
Writes a buffer into an internal LOB as specified. If LOB data exists, it is overwritten
with the data stored in the buffer. The buffer can be written to the LOB in a single
piece with this call, or it can be provided piecewise using callbacks or a standard
polling method.

Note:
When you read or write LOBs, specify a character set form (csfrm) that
matches the form of the locator itself.

When you use the polling mode for OCILobWrite(), the first call must specify values for
offset and amtp, but on subsequent polling calls to OCILobWrite(), you need not specify
these values.
If the value of the piece parameter is OCI_FIRST_PIECE, data may need to be provided
through callbacks or polling.
If a callback function is defined in the cbfp parameter, then this callback function is
invoked to get the next piece after a piece is written to the pipe. Each piece is written
from bufp. If no callback function is defined, then OCILobWrite() returns the

E-22

Appendix E

Deprecated Lob Functions

OCI_NEED_DATA error code. The application must call OCILobWrite() again to write more

pieces of the LOB. In this mode, the buffer pointer and the length can be different in
each call if the pieces are of different sizes and from different locations.
A piece value of OCI_LAST_PIECE terminates the piecewise write, regardless of whether
the polling or callback method is used.
If the amount of data passed to Oracle Database (through either input mechanism) is
less than the amount specified by the amtp parameter, an ORA-22993 error is returned.
This function is valid for internal LOBs only. BFILEs are not allowed, because they are
read-only. If the LOB is a BLOB, the csid and csfrm parameters are ignored.
If the client-side character set is varying-width, then the input amount is in bytes and
the output amount is in characters for CLOBs and NCLOBs. The input amount refers to the
number of bytes of data that the user wants to write into the LOB and not the number
of bytes in the bufp, which is specified by buflen. If data is written in pieces, the
amount of bytes to write may be larger than the buflen. The output amount refers to
the number of characters written into the server-side CLOB or NCLOB.
To write data in UTF-16 format, set the csid parameter to OCI_UTF16ID. If the csid
parameter is set, it overrides the NLS_LANG environment variable.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit or roll back your transaction. When an internal LOB is closed, it updates the
functional and domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobWrite2()
Writes a buffer into a LOB. This function must be used for LOBs of size greater
than 4 GB.

See Also:
•

PL/SQL REF CURSORs and Nested Tables in OCI for additional
information about Unicode format

•

The demonstration programs included with your Oracle Database
installation for a code sample showing the use of LOB reads and writes.

•

OCI Demonstration Programs

•

Runtime Data Allocation and Piecewise Operations in OCI for general
information about piecewise OCI operations

•

Polling Mode Operations in OCI

E-23

Appendix E

Deprecated Lob Functions

E.3.11 OCILobWriteAppend()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Writes data starting at the end of a LOB. This function is deprecated. Use
OCILobWriteAppend2().
Syntax
sword OCILobWriteAppend ( OCISvcCtx
*svchp,
OCIError
*errhp,
OCILobLocator *locp,
ub4
*amtp,
void
*bufp,
ub4
buflen,
ub1
piece,
void
*ctxp,
OCICallbackLobWrite
(
void
void
ub4
ub1
)
ub2
csid,
ub1
csfrm );

(cbfp)
*ctxp,
*bufp,
*lenp,
*piecep

Parameters
svchp (IN)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
locp (IN/OUT)
An internal LOB locator that uniquely references a LOB.
amtp (IN/OUT)
The value in amtp is the amount in either bytes or characters, as shown in Table E-7.
Table E-7

Characters or Bytes in amtp for OCILobWriteAppend()

LOB or BFILE

Input with Fixed-Width
Client-Side Character Set

Input with Varying-Width
Client-Side Character Set

Output

BLOBs and BFILEs

bytes

bytes

bytes

CLOBs and NCLOBs
1

characters

bytes

1

characters

The input amount refers to the number of bytes of data that the user wants to write into the LOB and not
the number of bytes in the bufp, which is specified by buflen. If data is written in pieces, the amount of
bytes to write may be larger than the buflen. The output amount refers to the number of characters
written into the server-side CLOB or NCLOB.

E-24

Appendix E

Deprecated Lob Functions

If the amount is specified on input, and the data is written in pieces, the parameter amtp
contains the total length of the pieces written at the end of the call (last piece written)
and is undefined in between. (Note it is different from the piecewise read case). An
error is returned if that amount is not sent to the server. If amtp is zero, then streaming
mode is assumed, and data is written until the user specifies OCI_LAST_PIECE.
If the client-side character set is varying-width, then the input amount is in bytes, not
characters, for CLOBs or NCLOBs.
bufp (IN)
The pointer to a buffer from which the piece is written. The length of the data in the
buffer is assumed to be the value passed in buflen. Even if the data is being written in
pieces, bufp must contain the first piece of the LOB when this call is invoked. If a
callback is provided, bufp must not be used to provide data or an error results.
buflen (IN)
The length, in bytes, of the data in the buffer. Note that this parameter assumes an 8bit byte. If your operating system uses a longer byte, the value of buflen must be
adjusted accordingly.
piece (IN)
Which piece of the buffer is being written. The default value for this parameter is
OCI_ONE_PIECE, indicating that the buffer is written in a single piece. The following other
values are also possible for piecewise or callback mode: OCI_FIRST_PIECE,
OCI_NEXT_PIECE, and OCI_LAST_PIECE.
ctxp (IN)
The context for the callback function. Can be NULL.
cbfp (IN)
A callback that can be registered to be called for each piece in a piecewise write. If
this is NULL, the standard polling method is used. The callback function must return
OCI_CONTINUE for the write to continue. If any other error code is returned, the LOB
write is terminated. The callback takes the following parameters:
ctxp (IN)
The context for the callback function. Can be NULL.
bufp (IN/OUT)
A buffer pointer for the piece.
lenp (IN/OUT)
The length (in bytes) of the data in the buffer (IN), and the length (in bytes) of the
current piece in bufp (OUT).
piecep (OUT)
Which piece: OCI_NEXT_PIECE or OCI_LAST_PIECE.
csid (IN)
The character set ID of the buffer data.
csfrm (IN)
The character set form of the buffer data.
The csfrm parameter has two possible nonzero values:
•

SQLCS_IMPLICIT - Database character set ID

•

SQLCS_NCHAR - NCHAR character set ID

E-25

Appendix E

Deprecated Streams Advanced Queuing Functions

The default value is SQLCS_IMPLICIT.
Comments
The buffer can be written to the LOB in a single piece with this call, or it can be
provided piecewise using callbacks or a standard polling method. If the value of the
piece parameter is OCI_FIRST_PIECE, data must be provided through callbacks or
polling. If a callback function is defined in the cbfp parameter, then this callback
function is invoked to get the next piece after a piece is written to the pipe. Each piece
is written from bufp. If no callback function is defined, then OCILobWriteAppend() returns
the OCI_NEED_DATA error code.
The application must call OCILobWriteAppend() again to write more pieces of the LOB.
In this mode, the buffer pointer and the length can be different in each call if the pieces
are of different sizes and from different locations. A piece value of OCI_LAST_PIECE
terminates the piecewise write.
OCILobWriteAppend() is not supported if LOB buffering is enabled.

If the LOB is a BLOB, the csid and csfrm parameters are ignored.
If the client-side character set is varying-width, then the input amount is in bytes, not
characters, for CLOBs or NCLOBs.
It is not mandatory that you wrap this LOB operation inside the open or close calls. If
you did not open the LOB before performing this operation, then the functional and
domain indexes on the LOB column are updated during this call. However, if you did
open the LOB before performing this operation, then you must close it before you
commit or roll back your transaction. When an internal LOB is closed, it updates the
functional and domain indexes on the LOB column.
If you do not wrap your LOB operations inside the open or close API, then the
functional and domain indexes are updated each time you write to the LOB. This can
adversely affect performance. If you have functional or domain indexes, Oracle
recommends that you enclose write operations to the LOB within the open or close
statements.
Related Topics
•

OCILobWriteAppend2()
Writes data starting at the end of a LOB. This function must be used for LOBs of
size greater than 4 GB.

See Also:
About Improving LOB Read/Write Performance

E.4 Deprecated Streams Advanced Queuing Functions
Describes deprecated Oracle Streams Advanced Queuing functions.
Table E-8 lists the deprecated Streams Advanced Queuing functions that are
described in this section.

E-26

Appendix E

Deprecated Streams Advanced Queuing Functions

Table E-8

Deprecated Streams Advanced Queuing Functions

Function

Purpose

OCIAQListen()

Listen on one or more queues on behalf of a list of agents.

E.4.1 OCIAQListen()
This function was deprecated in a release previous to Oracle Database 11g Release 2
(11.2).
Purpose
Listens on one or more queues on behalf of a list of agents. This function is
deprecated. UseOCIAQListen2().
Syntax
sword OCIAQListen (OCISvcCtx
OCIError
OCIAQAgent
ub4
sb4
OCIAQAgent
ub4

*svchp,
*errhp,
**agent_list,
num_agents,
wait,
**agent,
flags);

Parameters
svchpp (IN/OUT)
The service context handle.
errhp (IN/OUT)
An error handle that you can pass to OCIErrorGet() for diagnostic information when
there is an error.
agent_list (IN)
List of agents for which to monitor messages.
num_agents (IN)
Number of agents in the agent list.
wait (IN)
Timeout interval for the listen call.
agent (OUT)
Agent for which there is a message. OCIAgent is an OCI descriptor.
flags (IN)
Not currently used; pass as OCI_DEFAULT.
Comments
This is a blocking call that returns when there is a message ready for consumption for
an agent in the list. If there are no messages found when the wait time expires, an
error is returned.

E-27

Appendix E

Deprecated Streams Advanced Queuing Functions

Related Topics
•

OCIAQListen2()
Listens on one or more queues on behalf of a list of agents.

E-28

F
Multithreaded extproc Agent
What is the multithreaded extproc agent?
This appendix explains what the multithreaded extproc agent is, how it contributes to
the overall efficiency of a distributed database system, and how to administer it.
This section includes the following topics:
•

Why Use the Multithreaded extproc Agent?

•

Multithreaded extproc Agent Architecture

•

Administering the Multithreaded extproc Agent

F.1 Why Use the Multithreaded extproc Agent?
This section explains how the multithreaded extproc agent contributes to the efficiency
of external procedures.
This section includes the following topics:
•

The Challenge of Dedicated Agent Architecture

•

The Advantage of Multithreading

F.1.1 The Challenge of Dedicated Agent Architecture
By default, an extproc agent is started for each user session and the extproc agent
process terminates only when the user session ends.
This architecture can consume an unnecessarily large amount of system resources.
For example, suppose that several thousand user sessions simultaneously spawn
extproc agent processes. Because an extproc agent process is started for each
session, several thousand extproc agent processes run concurrently. The extproc
agent processes operate regardless of whether each individual extproc agent process
is active at the moment. Thus extproc agent processes and open connections can
consume a disproportionate amount of system resources. When sessions connect to
Oracle Database, this problem is addressed by starting the server in shared server
mode. Shared server mode allows database connections to be shared by a small
number of server processes.

F.1.2 The Advantage of Multithreading
The Oracle Database shared server architecture assumes that even when several
thousand user sessions are open, only a small percentage of these connections are
active at any given time.
In shared server mode, there is a pool of shared server processes. User sessions
connect to dispatcher processes that place the requested tasks in a queue. The tasks

F-1

Appendix F

Multithreaded extproc Agent Architecture

are picked up by the first available shared server processes. The number of shared
server processes is usually less that the number of user sessions.
The multithreaded extproc agent provides similar functionality for connections to
external procedures. The multithreaded extproc agent architecture uses a pool of
shared agent threads. The tasks requested by the user sessions are put in a queue
and are picked up by the first available multithreaded extproc agent thread. Because
only a small percentage of user connections are active at a given moment, using a
multithreaded extproc architecture allows more efficient use of system resources.

F.2 Multithreaded extproc Agent Architecture
One multithreaded extproc agent must be started for each system identifier (SID)
before attempting to connect to the external procedure. This is done using the agent
control utility agtctl. This utility is also used to configure the agent and to shut down
the agent.
Each Oracle Net listener that is running on a system listens for incoming connection
requests for a set of SIDs. If the SID in an incoming Oracle Net connect string is an
SID for which the listener is listening, then that listener processes the connection.
Further, if a multithreaded extproc agent was started for the SID, then the listener
passes the request to that extproc agent.
In the architecture for multithreaded extproc agents, each incoming connection request
is processed by different kinds of threads:
•

•

•

A single monitor thread. The monitor thread is responsible for:
–

Maintaining communication with the listener

–

Monitoring the load on the process

–

Starting and stopping threads when required

Several dispatcher threads. The dispatcher threads are responsible for:
–

Handling communication with the Oracle Database

–

Passing task requests to the task threads

Several task threads. The task threads handle requests from the Oracle Database
processes.

Figure F-1 illustrates the architecture of the multithreaded extproc agent. User
sessions 1 and 2 issue requests for callouts to functions in some DLLs. These
requests get serviced through heterogeneous services to the multithreaded extproc
agent. These requests get handled by the agent's dispatcher threads, which then pass
them on to the task threads. The task thread that is actually handling a request is
responsible for loading the respective DLL and calling the function therein.
•

All requests from a user session get handled by the same dispatcher thread. For
example, dispatcher 1 handles communication with user session 1, and
dispatcher 2 handles communication with user session 2. This is the case for the
lifetime of the session.

•

The individual requests can be serviced by different task threads. For example,
task thread 1 can handle the request from user session 1, and later handle the
request from user session 2.

F-2

Appendix F

Multithreaded extproc Agent Architecture

See Also:
Oracle Database Administrator’s Guide. for details on managing processes
for external procedures

Figure F-1

Multithreaded extproc Agent Architecture

User-Session
1

User-Session
2

Oracle
Server

Oracle
Server

HS

HS

Dispatcher
Thread 1

Dispatcher
Thread 2

Agent
Process

Task
Thread 1

Task
Thread 2

Task
Thread 3

DLLs

These three thread types roughly correspond to the Oracle Database multithreaded
server PMON, dispatcher, and shared server processes, respectively.

Note:
All requests from a user session go through the same dispatcher thread, but
can be serviced by different task threads. Also, several task threads can use
the same connection to the external procedure.

These topics explain each type of thread in more detail:
•

Monitor Thread

•

Dispatcher Threads

•

Task Threads

F-3

Appendix F

Multithreaded extproc Agent Architecture

See Also:
Administering the Multithreaded extproc Agent for more information
about starting and stopping the multithreaded exproc agent by using the
agent control utility agtctl

F.2.1 Monitor Thread
When the agent control utility agtctl starts a multithreaded extproc agent for a SID,
agtctl creates the monitor thread.
The monitor thread performs these functions:
•

Creates the dispatcher and task threads.

•

Registers the dispatcher threads with all the listeners that are handling
connections to this extproc agent. While the dispatcher for this SID is running, the
listener does not start a process when it gets an incoming connection. Instead, the
listener gives the connection to this same dispatcher.

•

Monitors the other threads and sends load information about the dispatcher
threads to all the listener processes handling connections to this extproc agent,
enabling listeners to give incoming connections to the least loaded dispatcher.

•

Continues to monitor each of the threads it has created.

F.2.2 Dispatcher Threads
How are dispatcher threads used?
Dispatcher threads perform these functions:
•

Accept incoming connections and task requests from Oracle Database servers.

•

Place incoming requests on a queue for a task thread to pick up.

•

Send results of a request back to the server that issued the request.

Note:
After a user session establishes a connection with a dispatcher, all
requests from that user session go to the same dispatcher until the end
of the user session.

F.2.3 Task Threads
How are task threads used?
Task threads perform these functions:
•

Pick up requests from a queue.

•

Perform the necessary operations.

•

Place the results on a queue for a dispatcher to pick up.

F-4

Appendix F

Administering the Multithreaded extproc Agent

F.3 Administering the Multithreaded extproc Agent
One multithreaded extproc agent must be started for each system identifier (SID)
before attempting to connect to the external procedure.
A multithreaded extproc agent is started, stopped, and configured by an agent control
utility called agtctl, which works like lsnrctl. However, unlike lsnrctl, which reads a
configuration file (listener.ora), agtctl takes configuration information from the
command line and writes it to a control file.
Before starting agtctl, ensure that Oracle Listener is running. Then use the agtctl
commands to set the agtctl configuration parameters (if you do not want their default
values) and to start agtctl, as in Example F-1.
You can use agtctl commands in either single-line command mode or shell mode.
Topics:
•

Agent Control Utility (agtctl) Commands

•

About Using agtctl in Single-Line Command Mode

•

Using Shell Mode Commands

•

Configuration Parameters for Multithreaded extproc Agent Control

Example F-1
agtctl
agtctl
agtctl
agtctl
agtctl
agtctl
agtctl

Setting Configuration Parameters and Starting agtctl

set max_dispatchers 2 ep_agt1
set tcp_dispatchers 1 ep_agt1
set max_task_threads 2 ep_agt1
set max_sessions
5 ep_agt1
unset listener_address ep_agt1
set listener_address "(address=(protocol=ipc)(key=extproc))" ep_agt1
startup extproc ep_agt1

F.3.1 Agent Control Utility (agtctl) Commands
What are the Agent Control Utility commands and what are they used for?
You can start and stop agtctl and create and maintain its control file by using the
commands shown in Table F-1.
Table F-1

Agent Control Utility (agtctl) Commands

Command

Description

startup

Starts a multithreaded extproc agent

shutdown

Stops a multithreaded extproc agent

set

Sets a configuration parameter for a multithreaded extproc agent

unset

Causes a parameter to revert to its default value

show

Displays the value of a configuration parameter

delete

Deletes the entry for a particular SID from the control file

exit

Exits shell mode

F-5

Appendix F

Administering the Multithreaded extproc Agent

Table F-1

(Cont.) Agent Control Utility (agtctl) Commands

Command

Description

help

Lists available commands

These commands can be issued in one of two ways:
•

You can issue commands from the UNIX or DOS shell. This mode is called singleline command mode.

•

You can enter agtctl and an AGTCTL> prompt appears. You then can enter
commands from within the agtctl shell. This mode is called shell mode.

The syntax and parameters for agtctl commands depend on the mode in which they
are issued.

Note:
•

All commands are case-sensitive.

•

The agtctl utility puts its control file in the directory specified by either
one of two environment variables, AGTCTL_ADMIN or TNS_ADMIN. Ensure that
at least one of these environment variables is set and that it specifies a
directory to which the agent has access.

•

If the multithreaded extproc agent requires that an environment variable
be set, or if the ENVS parameter was used when configuring the
listener.ora entry for the agent working in dedicated mode, then all
required environment variables must be set in the UNIX or DOS shell
that runs the agtctl utility.

F.3.2 About Using agtctl in Single-Line Command Mode
This section describes the use of agtctl commands.
They are presented in single-line command mode.
This section includes the following topics:
•

Setting Configuration Parameters for a Multithreaded extproc Agent

•

Starting a Multithreaded extproc Agent

•

Shutting Down a Multithreaded extproc Agent

•

Examining the Value of Configuration Parameters

•

Resetting a Configuration Parameter to Its Default Value

•

Deleting an Entry for a Specific SID from the Control File

•

Requesting Help

F-6

Appendix F

Administering the Multithreaded extproc Agent

F.3.2.1 Setting Configuration Parameters for a Multithreaded extproc Agent
Set the configuration parameters for a multithreaded extproc agent before you start the
agent.
If a configuration parameter is not specifically set, a default value is used.
Configuration parameters and their default values are shown in Table F-2.
Use the set command to set multithreaded extproc agent configuration parameters.
Syntax
agtctl set parameter parameter_value agent_sid
parameter is the parameter that you are setting.
parameter_value is the value being assigned to that parameter.
agent_sid is the SID that this agent services. This must be specified for single-line

command mode.
Example
agtctl set max_dispatchers 5 salesDB

F.3.2.2 Starting a Multithreaded extproc Agent
Use the startup command to start a multithreaded extproc agent.
Syntax
agtctl startup extproc agent_sid
agent_sid is the SID that this multithreaded extproc agent services. This must be
specified for single-line command mode.

Example
agtctl startup extproc salesDB

F.3.2.3 Shutting Down a Multithreaded extproc Agent
Use the shutdown command to stop a multithreaded extproc agent.
There are three forms of shutdown:
•

Normal (default)
agtctl asks the multithreaded extproc agent to terminate itself gracefully. All
sessions complete their current operations and then shut down.

•

Immediate
agtctl tells the multithreaded extproc agent to terminate immediately. The agent
exits immediately regardless of the state of current sessions.

•

Abort
Without talking to the multithreaded extproc agent, agtctl issues a system call to
stop it.

F-7

Appendix F

Administering the Multithreaded extproc Agent

Syntax
agtctl shutdown [immediate|abort] agent_sid
agent_sid is the SID that the multithreaded extproc agent services. It must be specified
for single-line command mode.

Example
agtctl shutdown immediate salesDB

F.3.2.4 Examining the Value of Configuration Parameters
To examine the value of a configuration parameter, use the show command.
Syntax
agtctl show parameter agent_sid
parameter is the parameter that you are examining.
agent_sid is the SID that this multithreaded extproc agent services. This must be
specified for single-line command mode.

Example
agtctl show max_dispatchers salesDB

F.3.2.5 Resetting a Configuration Parameter to Its Default Value
You can reset a configuration parameter to its default value using the unset command.
Syntax
agtctl unset parameter agent_sid
parameter is the parameter that you are resetting (or changing).
agent_sid is the SID that this multithreaded extproc agent services. It must be specified

for single-line command mode.
Example
agtctl unset max_dispatchers salesDB

F.3.2.6 Deleting an Entry for a Specific SID from the Control File
The delete command deletes the entry for the specified SID from the control file.
Syntax
agtctl delete agent_sid
agent_sid is the SID entry to delete.

Example
agtctl delete salesDB

F-8

Appendix F

Administering the Multithreaded extproc Agent

F.3.2.7 Requesting Help
Use the help command to view a list of available commands for agtctl or to see the
syntax for a particular command.
Syntax
agtctl help [command]
command is the name of the command whose syntax you want to view. The default is all
agtctl commands.

Example
agtctl help set

F.3.3 Using Shell Mode Commands
When issuing the AGTCTL> command, it results in the prompt AGTCTL>.
In shell mode, start agtctl by entering:
agtctl

Thereafter, because you are issuing commands from within the agtctl shell, you need
not prefix the command string with agtctl.
Set the name of the agent SID by entering:
AGTCTL> set agent_sid agent_sid

All subsequent commands are assumed to be for the specified SID until the agent_sid
value is changed. Unlike single-line command mode, you do not specify agent_sid in
the command string.
You can set the language for error messages as follows:
AGTCTL> set language language

The commands themselves are the same as those for the single-line command mode.
To exit shell mode, enter exit.
The following examples use shell mode commands:
•

Example: Setting a Configuration Parameter

•

Example: Starting a Multithreaded extproc Agent

F.3.3.1 Example: Setting a Configuration Parameter
How to set the value for the shutdown_address configuration parameter.
This example sets a value for the shutdown_address configuration parameter.
AGTCTL> set shutdown_address (address=(protocol=ipc)(key=oraDBsalesDB))

F-9

Appendix F

Administering the Multithreaded extproc Agent

F.3.3.2 Example: Starting a Multithreaded extproc Agent
How to start a multithreaded extproc agent.
This example starts a multithreaded extproc agent.
AGTCTL> startup extproc

F.3.4 Configuration Parameters for Multithreaded extproc Agent
Control
What do the configuration parameters for multithreaded extproc agent control do?
Table F-2 describes and gives the defaults of the configuration parameters for the
agent control utility.
Table F-2

Configuration Parameters for agtctl

Parameter

Description

Default Value

max_dispatchers

Maximum number of
dispatchers

1

tcp_dispatchers

Number of dispatchers
listening on TCP (the rest
are using IPC)

0

max_task_threads

Maximum number of task
threads

2

max_sessions

Maximum number of
sessions for each task
thread

5

listener_address

Address on which the
listener is listening (needed
for registration)

(ADDRESS_LIST=
(ADDRESS=
(PROTOCOL=IPC)
(KEY=PNPKEY))
(ADDRESS=
(PROTOCOL=IPC)
(KEY=listener_sid))
(ADDRESS=
(PROTOCOL=TCP)
(HOST=127.0.0.1)
(PORT=1521)))
Note: listener_sid is the IPC key of the
address, on the Oracle Database, on which the
listener is listening.

F-10

Appendix F

Administering the Multithreaded extproc Agent

Table F-2

(Cont.) Configuration Parameters for agtctl

Parameter

Description

Default Value

shutdown_address

Address the agent uses to
communicate with the
listener. This is the address
on which the agent listens
for all communication,
including shutdown
messages from agtctl.

(ADDRESS=
(PROTOCOL=IPC)
(KEY=listener_sid || agent_sid))
(ADDRESS=
(PROTOCOL=TCP)
(HOST=127.0.0.1)
(PORT=1521))
Notes:
•
•

agent_sid is the SID of the multithreaded
extproc agent.
|| indicates that listener_sid and
agent_sid are concatenated into one string.

max_dispatchers, tcp_dispatchers, max_task_threads, and max_sessions
To improve performance, you might need to change the values of some or all of the
parameters max_dispatchers, tcp_dispatchers, max_task_threads, and max_sessions.
You can calculate the optimum values of max_dispatchers, tcp_dispatchers,
max_task_threads with these formulas:
max_dispatchers = CEIL(x/y)
tcp_dispatchers = CEIL(x_tcpip/y)
max_task_threads = CEIL(x/max_sessions)

Where:
•

CEIL is a SQL function that returns the smallest integer greater than or equal to its

argument.
•

x is the maximum number of sessions that can be connected to extproc

concurrently.
•

y is the maximum number of connections that the system can support for each

dispatcher.
•

x_tcpip is the maximum number of sessions that can be connected to extproc

concurrently by TCP/IP.
(x - x_tcpip is the maximum number of sessions that can be connected to extproc
concurrently by IPC.)
There is no formula for computing the optimum value of max_sessions, which affects
max_task_threads.
You must fine-tune these parameter settings, based on the capability of your
hardware, and ensure that the concurrent threads do not exhaust your operating
system.
The value of max_dispatchers must be at least 1 (which is the default).
Example
Suppose:

F-11

Appendix F

Administering the Multithreaded extproc Agent

•

The maximum number of sessions that can be connected to extproc concurrently
(x) is 650.

•

The maximum number of sessions that can be connected to extproc concurrently
by TCP/IP (x_tcpip) is 400.
(The maximum number of sessions that can be connected to extproc concurrently
by IPC is 650-400=250.)

•

The maximum number of connections that the system can support for each
dispatcher (y) is 100.

•

The maximum number of sessions for each task thread (max_sessions) is 20.

The optimum values for these parameters are:
max_dispatchers = CEIL(650/100) = CEIL(6.5) = 7
tcp_dispatchers = CEIL(400/100) = CEIL(4)
= 4
max_task_threads = CEIL(650/20) = CEIL(32.5) = 33

That is, optimally:
•

The maximum number of dispatchers is seven.

•

Four of the seven dispatchers are listening on TCP/IP, and the remaining three are
listening on IPC.

•

The maximum number of task threads is 33.

listener_address and shutdown_address
The values of the configuration parameters listener_address and shutdown_address are
specified with ADDRESS, as shown in both Table F-2 and Example F-1. Within ADDRESS,
you can specify the parameter HOST, which can be either an IPv6 or IPv4 address or a
host name. If HOST is a host name, then these values of the optional ADDRESS parameter
IP are relevant:
IP Value

Meaning

FIRST

Listen on the first IP address returned by the DNS resolution of the host name.

V4_ONLY

Listen only on the IPv4 interfaces in the system.

V6_ONLY

Listen only on the IPv6 interfaces in the system.

For example, this value of listener_address or shutdown_address restricts it to IPv6
interfaces:
"(ADDRESS=(PROTOCOL=tcp)(HOST=sales)(PORT=1521)(IP=V6_ONLY))"

See Also:
Oracle Database Net Services Administrator's Guide for detailed information
about IPv6 support in Oracle Database

F-12

Index
Numerics
64-bit integer support, 5-12

A
administration handle, 16-1
attributes, A-33
description, 16-1
ADR, 3-24
ADR base location, 3-25
ADR, controlling creation, 3-28
ADRCI command-line tool, 3-26
ADT
See object type

advanced queuing
agent descriptor, 4-12
dequeue options descriptor, 4-12
descriptor, 4-16
enqueue options descriptor, 4-12
listen options descriptor, 4-12
message properties descriptor, 4-12, 4-13
notification descriptor, 4-12
advantages
OCI, 1-1
Agent Control Utility (agtctl)
commands
in shell mode, F-9
in single-line mode, F-6
list of, F-5
extproc administration and, F-5
extproc architecture and, F-2
allocation duration
example, 22-16
of objects, 22-15
ALTER SESSION SET CONTAINER, 17-2, 17-3
enhancements on OCI calls with, 17-2
restrictions on OCI calls with, 17-3
ALTER SESSION SWITCH CONTAINER
SWITCH SERVICE
restrictions on OCI calls with, 17-4
alternatives to OCI
OCCI, 1-3
ODPI-C, 1-3
Pro*C/C++, 1-3

ANSI DATE descriptor, 4-12
AnyData, 20-26
AnyDataSet, 20-26
AnyType, 20-26
application context, 10-28
Application Continuity, 12-22
constructs not supported, 12-27
failed replay, 12-25
following a recoverable error, 12-23
successful replay criteria, 12-24
successful replay side effects to be aware of,
12-27
supported OCI functions for fail over, 12-26
what disables it in OCI, 12-24
when it is most effective, 12-25
application initialization, 4-19
AQ
See Oracle Streams Advanced Queuing.

argument attributes, 8-19
arrays
binds, 20-35
defines, 20-39
DML, maximum rows, 7-4
skip parameter for, 7-24
arrays of structures, 7-22
indicator variables, 7-25
OCI calls used, 7-24
skip parameters, 7-23
atomic NULLs, 19-28
attribute descriptor object, 20-25
attributes
administration handle, A-33
authentication handle, A-20
authentication information handle, A-21
bind handle, A-50
complex object retrieval (COR) descriptor,
A-72
complex object retrieval (COR) handle, A-71
connection pool handle, A-34
continuous query notification, A-90
continuous query notification descriptor, A-91
define handle, A-54
description, A-54
describe handle, A-56

Index-1

Index

attributes (continued)
direct path loading
column array handle, A-105
column parameter, A-106
context handle, A-96
function context handle, A-103
handle, A-95
stream handle, A-106
environment handle, A-2
error handle, A-9
event handle, A-113
LOB locator, A-70
notification descriptor, A-93
OCIAQAgent descriptor, A-82
OCIAQDeqOptions descriptor, A-74
OCIAQEnqOptions descriptor, A-73
OCIAQMsgProperties descriptor, A-78
OCIServerDNs descriptor, A-83
of handles, 4-10
of objects, 19-17
of parameter descriptors, 8-5
of parameters, 8-5
parameter descriptor, A-58
process handle, A-111
server handle, A-15
service context handle, A-10
session pool handle, A-35
Shard Instance Descriptor, A-58
statement handle, A-40
subscription handle, A-83
transaction handle, A-39
user session handle, A-21
authentication
by Distinguished Name, 10-17
by X.509 Certificate, 10-17
management, 10-11
authentication handle
attributes, A-20
authentication information handle, 4-3
authorize functions, 25-3
auto_tune, 15-14
auto-tuning
client session features
comparison of auto-tuning parameters,
15-16
enabling and disabling, 15-19
usage examples of client attributes,
15-18
OCI client attributes, 15-13
OCI client session features
benefits of, 15-13
OCI client statement cache, 15-12
Automatic Diagnostic Repository (ADR), 3-24

B
BASICFILE parameter, 9-28
batch error mode, 6-9
batch jobs, authenticating users in, 10-13
BFILE
data type, 5-24
BFILE data type locator descriptor, 4-12
BINARY_DOUBLE data type, 5-6
BINARY_FLOAT data type, 5-6
bind and define in statement caching, 15-5
bind functions, 25-58
bind handle
attributes, A-50
description, 4-8
bind operations, 6-6, 7-1, 20-33
associations made, 7-1
example, 7-6
initializing variables, 7-1
LOBs, 7-10
named data types, 20-33
named versus positional, 7-3
OCI array interface, 7-4
OCI_DATA_AT_EXEC mode, 7-16
PL/SQL, 7-5
positional versus named, 7-3
REF CURSOR variables, 7-17
REFs, 20-34
steps used, 7-6
bind placeholders, 6-7
binding
arrays, 20-35
buffer expansion, 7-38
multiple buffers, 7-25
OCINumber, 20-41
PL/SQL placeholders, 4-38
summary, 7-9
BLOB data type, 5-25
blocking modes, 4-36
branches
detaching, 10-6
preparing multiple, 10-7
resuming, 10-6
buffer expansion during binding, 7-38
buffered messaging, 13-29
buffering LOB operations, 9-12
building OCI applications, B-1

C
C data types
manipulating with OCI, 20-4
cache functions
server round-trips, C-5
cache, client result, 15-12

Index-2

Index

callbacks
dynamic registrations, 14-6
for LOB operations, 9-15
for reading LOBs, 9-15
for writing LOBs, 9-17
from external procedures, 14-11
LOB streaming interface, 9-15
parameter modes, 25-97
registration for transparent application
failover, 12-11
restrictions, 14-8
user-defined functions, 14-1
canceling a cursor, 26-5
canceling OCI calls, 4-33
cartridge functions, 29-1
CASE OTT parameter, 24-29
CDBs
enhancements on OCI API calls with, 17-1
restrictions on OCI API calls with, 17-2
change notification descriptor, 4-13
CHAR
external data type, 5-19
character set conversion of Unicode, 4-45
character set form, 7-34
character set ID, 7-34
Unicode, A-50, A-54
character sets
OCI SODA client, 36-1
XStream OCI interface, 34-2
character-length semantics, 7-38–7-40, 8-25
CHARZ
external data type, 5-21
checkerr() listing, 26-154
client and server interoperability, 3-19
client auto-tuning
comparison of auto-tuning parameters, 15-16
OCI client attributes, 15-13
session features
benefits of, 15-13
enabling and disabling, 15-19
usage examples of client attributes, 15-18
client result cache, 15-12
client statement cache auto-tuning
OCI client session feature, 15-12
CLIENTCONTEXT namespace, 10-29
CLOB
data type, 5-25
code
example programs, B-1
list of demonstration programs, B-1
CODE OTT parameter, 24-27
coding guidelines
reserved words, 4-35
coherency
of object cache, 22-4

collections
attributes, 8-13
data manipulation functions, 20-19
describing, 8-1
description, 20-17
functions for manipulating, 20-18
multilevel, 20-22
scanning functions, 20-19
column objects
direct path loading of, 21-18
columns
attributes, 8-4, 8-15
commit, 4-25
in object applications, 22-15
one-phase for global transactions, 10-7
two-phase for global transactions, 10-7
compatibility
of releases in OCI, 3-19
compiling
OCI application, D-2
OCI with Oracle XA, D-5
XA Library, D-4
complex object descriptor, 4-12
complex object retrieval, 19-20
descriptor attributes, A-72
handle, 4-9
handle attributes, A-71
implementing, 19-23
navigational prefetching, 19-24
complex object retrieval (COR) descriptor, 4-16
CONFIG OTT parameter, 24-28
connect functions, 25-3
connection, 4-19
connection mode
nonblocking, 4-36
connection pool handle
attributes, A-34
description, 4-10
initializing, 11-18
connection pooling, 11-15, 11-23
code example, 11-23
creating, 11-18
database resident, 11-11
connection pools and TAF, 11-17
consistency
of object cache, 22-4
continuous query notification, 13-1
attributes, A-90
descriptor attributes, A-91
copying
objects, 19-31
COR
See complex object retrieval

creating
objects, 19-31

3

Index

cursor cancellation, 26-5
custom pools, 18-6

D
data cartridges
OCI functions, 4-1, 29-1
data definition language, 1-5
SQL statements, 1-5
data manipulation language, 1-6
SQL statements, 1-6
data structures, 4-3
See also descriptors

data types
ANSI DATE, 5-26
BFILE, 5-24
binding and defining, 20-39
BLOBs (binary large objects), 5-25
CLOB, 5-25
conversions, 5-28
direct path loading, 21-3, A-107
external, 5-3, 5-7
FILE, 5-24
for piecewise operations, 7-46
internal, 5-4
internal codes, 5-4
INTERVAL DAY TO SECOND, 5-27
INTERVAL YEAR TO MONTH, 5-27
manipulating with OCI, 20-4
mapping and manipulation functions, C-6
mapping from Oracle to C, 20-2
mapping, Oracle methodology, 20-3
mapping, OTT utility, 24-9
NCLOB, 5-25
Oracle, 5-1
TIMESTAMP, 5-26
TIMESTAMP WITH LOCAL TIME ZONE,
5-27
TIMESTAMP WITH TIME ZONE, 5-26
database connection
for object applications, 19-10
database resident connection pooling, 11-11
database type attributes
type OCI_PTYPE_DATABASE, 8-21
databases
attributes, 8-21
describing, 8-1
shutting down, 16-1
starting up, 16-1
DATE
external data type, 5-17
date cache, 21-14
date descriptor, 4-16
DATE, ANSI
data type, 5-26

datetime
avoiding unexpected results, 5-27
datetime and date
migration rules, 5-32
datetime descriptor, 4-16
DDL
See data definition language

DEDUPLICATE, 9-28
default file name extensions
OTT utility, 24-36
default name mapping
OTT utility, 24-36
define
arrays, 20-39
return and error codes, 4-28
define functions, 25-58
define handle
attributes, A-54
description, 4-8
define operations, 6-16, 7-17, 20-36
example, 7-18
LOBs, 7-20
named data types, 20-36
piecewise fetch, 7-22
PL/SQL output variables, 7-22
REFs, 20-37
steps used, 7-18
defining
multiple buffers, 7-25
OCINumber, 20-41
deletes
positioned, 4-34
demonstration files location, 3-1
demonstration programs, B-1, D-2
list, B-1
describe
explicit, 6-12, 6-15
explicit and implicit, 8-4
implicit, 6-12, 6-13
of collections, 8-1
of databases, 8-1
of packages, 8-1
of schemas, 8-1
of sequences, 8-1
of stored functions, 8-1
of stored procedures, 8-1
of synonyms, 8-1
of tables, 8-1
of types, 8-1
of views, 8-1
select list, 6-12
describe functions, 25-58
describe handle
attributes, A-56
description, 4-9

Index-4

Index

describe operation
server round-trips, C-6
describing the stored procedure
example, 8-29
descriptor, 4-12
advanced queuing
agent, 4-12
dequeue options, 4-12
enqueue options, 4-12
listen options, 4-12
message properties, 4-12, 4-13
notification, 4-12
allocating, 4-19
ANSI DATE, 4-12
BFILE data type locator, 4-12
change notification, 4-13
complex object, 4-12
complex object retrieval, 4-16
distinguished names of the database servers
in a registration request, 4-12
functions, 25-45
INTERVAL DAY TO SECOND, 4-12
INTERVAL YEAR TO MONTH, 4-12
LOB data type locator, 4-12
objects, 20-25
parameter, 4-15
read-only parameter, 4-12
result set, 4-12
row change, 4-13
ROWID, 4-12, 4-15
shard key and shard group key, 4-13
snapshot, 4-12, 4-14
table change, 4-13
TIMESTAMP, 4-12
TIMESTAMP WITH LOCAL TIME ZONE,
4-12
TIMESTAMP WITH TIME ZONE, 4-12
user callback, 4-12
detaching branches, 10-6
DIAG_ADR_ENABLED sqlnet.ora parameter,
3-28
DIAG_DDE_ENABLED sqlnet.ora parameter,
3-28
DIAG_RESTRICTED, 3-28
DIAG_SIGHANDLER_ENABLED, 3-28
direct path loading, 21-1
attribute
OCI_ATTR_DIRPATH_NO_INDEX_ERRORS,
21-37
column array handle attributes, A-105
column parameter attributes, A-106
context handle attributes, A-96
data types of columns, 21-3, A-107
direct path column array handle, 21-6
direct path context handle, 21-4

direct path loading (continued)
direct path function context, 21-5
direct path stream handle, 21-6
example, 21-9
function context handle attributes, A-103
functions, 21-7, 26-96
handle attributes, A-95
handles, 4-10, 21-4
in pieces, 21-32
limitations, 21-8
of date columns, 21-14
stream handle attributes, A-106
directory structures, D-2
dispatcher thread, F-2
distinguished names of the database servers in a
registration request descriptor, 4-12
DML
See data manipulation language

DRCP (database resident connection pooling),
11-11
duration
example, 22-16
of objects, 22-15
dynamic registration
Oracle XA Library, D-5
dynamically linked applications, 3-20

E
edition-based redefinition, 10-31
editions, 10-31
embedded objects
fetching, 19-15
embedded SQL, 1-8
mixing with OCI calls, 1-8
empty LOB, inserting, 9-19
enable, 15-15
enhanced DML array
feature, 6-9
enhancements
on OCI API calls with CDBs in general, 17-1
on OCI calls with ALTER SESSION SET
CONTAINER, 17-2
environment handle
attributes, A-2
description, 4-6
environment handle attribute, 4-41
error checking example, 26-154
error codes
define calls, 4-28
navigational functions, 27-4
error handle
attributes, A-9
description, 4-6

5

Index

errors
handling, 4-27
handling in object applications, 19-35
ERRTYPE OTT parameter, 24-28
evaluation context
attributes, 8-23
evaluation context attributes, 8-23
event handle attributes, A-113
example
demonstration programs, B-1
executing SQL statements, 6-7
execution
against multiple servers, 6-5
modes, 6-9
snapshots, 6-8
explicit describe, 6-12, 8-26
extensions
OTT utility default file name, 24-36
external data types, 5-3, 5-7
CHAR, 5-19
CHARZ, 5-21
conversions, 5-28
DATE, 5-17
FLOAT, 5-15
INTEGER, 5-14
LOB, 5-23
LONG, 5-16
LONG RAW, 5-19
LONG VARCHAR, 5-19
LONG VARRAW, 5-19
named data types, 5-21
NUMBER, 5-11
RAW, 5-18
REF, 5-22
ROWID, 5-22
SQLT_BLOB, 5-23
SQLT_CLOB, 5-23
SQLT_NCLOB, 5-23
SQLT_NTY, 5-21
SQLT_REF, 5-22
STRING, 5-15
UNSIGNED, 5-19
VARCHAR, 5-17
VARCHAR2, 5-9
VARNUM, 5-16
VARRAW, 5-18
external procedure functions
return codes, 29-1
with_context type, 29-1
external procedures
OCI callbacks, 14-11
externally initialized context, 10-22
extproc agent, F-1

F
failover
callback example, 12-11
failover callbacks, 12-7
structure and parameters, 12-10
fault diagnosability, 3-24
read or write client driver layer name, A-21
featureRelease, client library version, 26-153
fetch
piecewise, 7-45, 7-52
fetch operation, 6-16
LOB data, 6-17
setting prefetch count, 6-17
FILE
associating with operating system file, 9-3
data type, 5-24
FLOAT
external data type, 5-15
flushing, 22-11
object changes, 19-15
objects, 22-11
freeing
objects, 19-31, 22-9
functions
attributes, 8-8

G
generic documentation references
compiling and linking OCI application, D-2,
D-3
demonstration programs, D-2
invoking OTT from the command line, D-6
XA linking file names, D-4
global transactions, 10-3
globalization support, 4-39
byte order is native to machine
on which the application is running, 4-43
OCI functions, 4-1
GTRID
See transaction identifier

H
HA event notification, 12-2
handle attributes, 4-10
collection, 4-11
document, 4-12
OCISodaColl, 4-11
OCISodaDoc, 4-12
SODA collection, A-61
SODA document, A-59
handle functions, 25-45
handle type constants, 4-3

Index-6

Index

handles, 4-3
administration handle, 16-1, A-33
advantages of, 4-5
allocating, 4-5, 4-19
bind handle, 4-8, A-50
C data types, 4-3
child freed when parent freed, 4-5
complex object retrieval handle, 4-9, A-71
connection pool handle, 4-10, 11-18, A-34
define handle, 4-8, A-54
describe handle, 4-9, A-56
direct path loading, 4-10
environment handle, 4-6, A-2
error handle, 4-6, A-9
freeing, 4-5
process attributes, A-111
server handle, 4-6, A-15
service context handle, 4-6, A-10
statement handle, 4-8, A-40
subscription, 4-9, 13-4
transaction handle, 4-6, A-39
types, 4-3
user session handle, 4-6, A-21
header files
location of, 1-16, 3-1, D-2
oratypes.h, 5-37
HFILE OTT parameter, 24-28

I
implicit describe, 8-26
implicit results
OCI support for, 15-9
inbound servers
OCI interface, 34-2
indicator variables, 4-31
arrays of structures, 7-25
for named data types, 4-31, 4-32
for REFs, 4-31, 4-32
named data type defines, 20-37
PL/SQL OUT binds, 20-37
REF defines, 20-37
with named data type bind, 20-35
with REF bind, 20-35
init.ora security parameters, 10-32
INITFILE OTT parameter, 24-27
INITFUNC OTT parameter, 24-28
initialize
all buffers, 7-5
functions, 25-3
inserting an empty LOB, 9-19
inserts
piecewise, 7-45, 7-47
Instant Client, 2-1
Instant Client Light (English), 2-7

INTEGER external data type, 5-14
interacting with Oracle Database, D-4
internal codes for data types, 5-4
internal data types, 5-4
conversions, 5-28
INTERVAL DAY TO SECOND data type, 5-27
INTERVAL DAY TO SECOND descriptor, 4-12
interval descriptor, 4-16
INTERVAL YEAR TO MONTH data type, 5-27
INTERVAL YEAR TO MONTH descriptor, 4-12
intype file
providing when running OTT utility, 24-8
structure of, 24-31
INTYPE File Assistant, D-6
INTYPE OTT parameter, 24-26
IP address
IPv4, A-83
IPv6, A-83
IPv6 addressing, 13-4, A-83

K
KEEP_DUPLICATES, 9-28
key words, 4-35

L
LCR column flags, 35-19, 35-21, 35-26, 35-50,
35-65
LDAP registration of publish-subscribe
notification, 13-9
libraries
oci.lib, D-3
linking
OCI application, D-3
OCI with Oracle XA, D-5
XA Library, D-4
list attributes
type OCI_PTYPE_LIST, 8-20
lists
attributes, 8-20
lmsgen utility, 4-47
LoadLibrary, D-3
LOB and LONG bind restrictions, 7-12
LOB data type locator descriptor, 4-12
LOB functions, 26-14
server round-trips, C-3
LOB locator, 4-14
attributes, A-70
LOBs
amount and offset parameters, 26-14
attributes of transient objects, 9-4
binding, 7-10
buffering, 9-12
callbacks, 9-15

7

Index

LOBs (continued)
character sets, 26-14
creating, 9-2
creating temporary, 9-19
defining, 7-20
duration of temporary, 9-20
example of temporary, 9-22
external data types, 5-23
failover does not work, 12-13
fetching data, 6-17
fixed-width character sets, 26-14
freeing temporary, 9-19
greater than 4 GB, 9-5
locator, 4-14
modifying, 9-2
OCI functions, 9-9
prefetching, 9-25
size maximum, 9-5
temporary, 9-18
varying-width character sets, 26-14
locator, 4-12
for LOB data type, 4-14
locking, 22-13
objects, 22-13
optimistic model, 22-14
logical transaction ID (LTXID)
Transaction Guard, 12-14
LONG
external data type, 5-16
LONG RAW
external data type, 5-19
LONG VARCHAR
external data type, 5-19
LONG VARRAW
external data type, 5-19

M
makefiles, 3-1, B-1
marking objects, 22-10
memory_target, 15-16
meta-attributes
of objects, 19-17
of persistent objects, 19-17
of transient objects, 19-20
method descriptor object, 20-25
method results
type OCI_PTYPE_TYPE_RESULT, 8-19
migration
session, 10-11, 25-28
miscellaneous functions, 26-151
mode
agtctl command, F-5
monitor thread, F-2

multi-property tags, 11-3
PL/SQL fix-up callback example, 11-4
multiple servers
executing statement against, 6-5
multithreaded development
basic concepts, 10-34
multithreaded extproc agent, F-1
multithreading, 10-34
mutexes, 10-34

N
name-value pair attributes
type OCI_PTYPE_NAME_VALUE, 8-25
named data types
binding, 20-33
binding and defining, 20-39
defining, 20-36
definition, 5-21
external data types, 5-21
indicator variables, 4-32
indicator variables for, 4-31
native double, 5-28
native float, 5-28
navigation, 22-18
navigational functions
error codes, 27-4
return values, 27-4
terminology, 27-3
NCHAR
issues, 7-33
NCLOB
data type, 5-25
nested table
direct path loading of, 21-17
element ordering, 20-21
functions for manipulating, 20-21
new release, relinking, 3-20
NLS_LANG, 4-40
NLS_NCHAR, 4-40
NOCOMPRESS, 9-28
non-deferred linkage no longer supported, 10-34
nonblocking mode, 4-36
nonfinal object tables
direct path loading of, 21-31
notification descriptor attributes, A-93
NULL indicator
setting for an object attribute, 19-28
NULL indicator struct, 19-28
generated by OTT, 19-8
nullness
of objects, 19-28
NULLs
atomic, 19-28
inserting, 4-32

Index-8

Index

NULLs (continued)
inserting into database, 4-31
inserting using indicator variables, 4-31
NUMBER
external data type, 5-11

O
object applications
commit, 22-15
database connection, 19-10
rollback, 22-15
object cache, 22-1
coherency, 22-4
consistency, 22-4
initializing, 19-9
loading objects, 22-6
memory parameters, 22-4
operations on, 22-5
removing objects, 22-6
setting the size of, 22-4
object functions
server round-trips, C-5
object identifiers, 19-4, 19-33, 19-34
for persistent objects, 19-4
object references, 19-10, 19-33
See also REFs

object run-time environment
initializing, 19-9
object tables
direct path loading of, 21-30
object type, 19-8
representing in C applications, 19-8
Object Type Translator utility
See OTT utility

object view, 19-17
objects
accessing with OCI, 24-20
allocation duration, 22-15
array pin, 19-13
attributes, 19-17
manipulating, 19-13
client-side cache, 22-1
copying, 19-31
creating, 19-31
duration, 22-15
flushing, 22-11
flushing changes, 19-15
freeing, 19-31, 22-9
lifetime, 27-2
LOB attributes of transient objects, 9-4
locking, 22-13
manipulating with OCI, 24-20
marking, 19-15, 22-10
memory layout of instance, 22-17

objects (continued)
memory management, 22-1
meta-attributes, 19-17
navigation, 22-18
simple, 22-18
NCHAR and NVARCHAR2 attribute of, 20-2
NULL values, 19-28
OCI object application structure, 19-3
persistent, 19-4
pin count, 19-28
pin duration, 22-15
pinning, 19-11, 22-7
refreshing, 22-12
secondary memory, 22-17
terminology, 19-4, 27-2
top-level memory, 22-17
transient, 19-4, 19-5
types, 19-4, 27-2
unmarking, 22-10
unpinning, 22-8
use with OCI, 19-1
OCCI
alternative to OCI, 1-3
OCI, 1-1
aborting calls, 4-33
accessing and manipulating objects, 24-20
advantages, 1-1
object support, 1-10
Oracle XA Library, D-5
overview, 1-1
parts of, 1-1
sample programs, D-2
OCI applications, 4-1
compiling, 1-3, D-2
general structure, 4-1
initialization example, 4-23
linking, 1-3, D-3
running, D-4
steps, 4-17
structure, 4-1
structure using objects, 19-3
terminating, 4-26
using the OTT utility with, 24-19
with objects
initializing, 19-9
OCI demonstration programs
demo subdirectory, 3-2
OCI environment
initializing for objects, 19-9
OCI functions
canceling calls, 4-33
data cartridges, 4-1
globalization, 4-1
not supported, 3-24
obsolescent, 3-22

9

Index

OCI functions (continued)
return codes, 4-27, 4-29
OCI handle types, 4-3
OCI interface
XStream, 34-1
OCI navigational functions, 22-21
flush functions, 22-22
mark functions, 22-22
meta-attribute accessor functions, 22-23
miscellaneous functions, 22-23
naming scheme, 22-21
pin/unpin/free functions, 22-22
OCI process
initializing for objects, 19-9
OCI program
See OCI applications

OCI relational functions
connect, authorize, and initialize, 25-3
guide to reference entries, 29-1
Oracle Streams Advanced Queuing and
publish-subscribe, 26-78, E-26
OCI session pool, 18-5
OCI session pool configuration
using oraaccess.xml, 3-17
OCI SODA functions, 36-1
OCI support for implicit results, 15-9
OCI_ATTR_ACCESS_BANNER, 10-33
server handle attribute, A-15
OCI_ATTR_ACTION, 10-25
user session handle attribute, A-21
OCI_ATTR_ADMIN_PFILE
administration handle attribute, A-33
OCI_ATTR_AGENT_ADDRESS
OCIAQAgent descriptor attribute, A-82
OCI_ATTR_AGENT_NAME
OCIAQAgent descriptor attribute, A-82
OCI_ATTR_AGENT_PROTOCOL
OCIAQAgent descriptor attribute, A-82
OCI_ATTR_ALLOC_DURATION
environment handle attribute, A-2
OCI_ATTR_APPCTX_ATTR, 10-23
user session handle attribute, A-21
OCI_ATTR_APPCTX_LIST, 10-23
user session handle attribute, A-21
OCI_ATTR_APPCTX_NAME, 10-23
user session handle attribute, A-21
OCI_ATTR_APPCTX_SIZE, 10-23, 25-32
user session handle attribute, A-21
OCI_ATTR_APPCTX_VALUE, 10-23
user session handle attribute, A-21
OCI_ATTR_AQ_NTFN_GROUPING_
MSGID_ARRAY
notification descriptor attribute, A-93
OCI_ATTR_AQ_NTFN_GROUPING_COUNT
notification descriptor attribute, A-93

OCI_ATTR_ATTEMPTS
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_AUDIT_BANNER
user session handle attribute, A-21
OCI_ATTR_AUTOCOMMIT_DDL
attribute, 8-21
OCI_ATTR_AUTOTUNING_ENABLED
user session handle attribute, A-21
OCI_ATTR_BIND_COUNT
statement handle attribute, A-40
OCI_ATTR_BIND_DN
environment handle attribute, A-2
OCI_ATTR_BREAK_ON_NET_TIMEOUT
server handle attribute, A-15
OCI_ATTR_BUF_ADDR
direct path loading stream handle attribute,
A-106
OCI_ATTR_BUF_SIZE
direct path loading
context handle attribute, A-96
stream handle attribute, A-106
OCI_ATTR_CACHE
attribute, 8-15
OCI_ATTR_CACHE_ARRAYFLUSH, 22-11
environment handle attribute, A-2
OCI_ATTR_CACHE_MAX_SIZE, 22-4
environment handle attribute, A-2
OCI_ATTR_CACHE_OPT_SIZE, 22-4
environment handle attribute, A-2
OCI_ATTR_CALL_TIME, 10-25
user session handle attribute, A-21
OCI_ATTR_CALL_TIMEOUT
service contect handle attribute, A-10
OCI_ATTR_CATALOG_LOCATION
attribute, 8-21
OCI_ATTR_CERTIFICATE, 10-17, 25-32
user session handle attribute, A-21
OCI_ATTR_CHAR_COUNT
bind handle attribute, A-50
define handle attribute, A-54
OCI_ATTR_CHAR_SIZE, 8-15
attribute, 8-25, 8-26
OCI_ATTR_CHAR_USED, 8-15
attribute, 8-25
OCI_ATTR_CHARSET_FORM, 7-34
attribute, 8-11, 8-13, 8-15, 8-19
bind handle attribute, A-50
define handle attribute, A-54
OCI_ATTR_CHARSET_ID
attribute, 8-11, 8-13, 8-15, 8-19, 8-21
bind handle attribute, A-50
define handle attribute, A-54
direct path loading
column parameter attribute, A-107

Index-10

Index

OCI_ATTR_CHARSET_ID (continued)
direct path loading (continued)
context handle attribute, A-96
OCI_ATTR_CHDES_DBNAME
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_NFTYPE
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_ROW_OPFLAGS
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_ROW_ROWID
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_TABLE_CHANGES
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_TABLE_NAME
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_TABLE_OPFLAGS
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHDES_TABLE_ROW_CHANGES
continuous query notification descriptor
attribute, A-91
OCI_ATTR_CHNF_CHANGELAG
continuous query notification attribute, A-90
OCI_ATTR_CHNF_OPERATIONS
continuous query notification attribute, A-90
OCI_ATTR_CHNF_REGHANDLE
statement handle attribute, A-40
OCI_ATTR_CHNF_ROWIDS
continuous query notification attribute, A-90
OCI_ATTR_CHNF_TABLENAMES
continuous query notification attribute, A-90
OCI_ATTR_CLIENT_IDENTIFIER, 10-18
user session handle attribute, A-21
OCI_ATTR_CLIENT_INFO, 10-25, 25-32
user session handle attribute, A-21
OCI_ATTR_CLUSTERED
attribute, 8-8
OCI_ATTR_COL_COUNT
direct path loading column array handle
attribute, A-105
OCI_ATTR_COL_PROPERTIES, 8-15
OCI_ATTR_COLLATION_ID, 8-15
bind handle attribute, A-50
OCI_ATTR_COLLECT_CALL_TIME, 10-24
user session handle attribute, A-21
OCI_ATTR_COLLECTION_ELEMENT
attribute, 8-9
OCI_ATTR_COLLECTION_TYPECODE
attribute, 8-9

OCI_ATTR_COMMENT
attribute, 8-22, 8-23
OCI_ATTR_COMPLEXOBJECT_
COLL_OUTOFLINE
COR handle attribute, A-71
OCI_ATTR_COMPLEXOBJECT_LEVEL
COR handle attribute, A-71
OCI_ATTR_COMPLEXOBJECTCOMP
_TYPE_LEVEL
COR descriptor attribute, A-72
OCI_ATTR_COMPLEXOBJECTCOMP_TYPE
COR descriptor attribute, A-72
OCI_ATTR_CONDITION
attribute, 8-22
OCI_ATTR_CONN_BUSY_COUNT
connection pool handle attribute, A-34
OCI_ATTR_CONN_INCR
connection pool handle attribute, A-34
OCI_ATTR_CONN_MAX
connection pool handle attribute, A-34
OCI_ATTR_CONN_MIN
connection pool handle attribute, A-34
OCI_ATTR_CONN_NOWAIT
connection pool handle attribute, A-34
OCI_ATTR_CONN_OPEN_COUNT
connection pool handle attribute, A-34
OCI_ATTR_CONN_TIMEOUT
connection pool handle attribute, A-34
OCI_ATTR_CONNECTION_CLASS
user session handle attribute, A-21
OCI_ATTR_CONSUMER_NAME, A-74
notification descriptor attribute, A-93
OCI_ATTR_CORRELATION
OCIAQDeqOptions descriptor attribute, A-74
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_CQ_QUERYID
statement handle attribute, A-40
OCI_ATTR_CQDES_OPERATION
direct path loading handle attribute, A-94
OCI_ATTR_CQDES_QUERYID
direct path loading handle attribute, A-94
OCI_ATTR_CQDES_TABLE_CHANGES
direct path loading handle attribute, A-94
OCI_ATTR_CURRENT_POSITION
attribute, 6-19
statement handle attribute, A-40
OCI_ATTR_CURRENT_SCHEMA, 17-3, 25-32
user session handle attribute, A-21
OCI_ATTR_CURSOR_COMMIT_ BEHAVIOR
attribute, 8-21
OCI_ATTR_DATA_SIZE, 8-25
attribute, 8-11, 8-13, 8-15, 8-19, 8-26
direct path loading column parameter
attribute, A-107

11

Index

OCI_ATTR_DATA_TYPE
attribute, 8-3, 8-11, 8-13, 8-15, 8-19
direct path loading column parameter
attribute, A-107
OCI_ATTR_DATEFORMAT
direct path loading
column parameter attribute, A-107
context handle attribute, A-96
OCI_ATTR_DBDOMAIN
event handle attribute, A-113
OCI_ATTR_DBNAME
event handle attribute, A-113
OCI_ATTR_DBOP, 10-25, 25-32
user session handle attribute, A-21
OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE
user session handle attribute, A-21
OCI_ATTR_DELAY
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_DEQ_MODE
OCIAQDeqOptions descriptor attribute, A-74
OCI_ATTR_DEQ_MSGID
OCIAQDeqOptions descriptor attribute, A-74
OCI_ATTR_DEQCOND
OCIAQDeqOptions descriptor attribute, A-74
OCI_ATTR_DESC_PUBLIC, 25-102
OCI_ATTR_DIRPATH_DCACHE_DISABLE,
21-15
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_DCACHE_HITS, 21-15
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_DCACHE_MISSES,
21-15
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_DCACHE_NUM, 21-15
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_DCACHE_SIZE, 21-15
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_DEF_EXP_CACHE_SIZE
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_DEFAULTS
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_EXPR_TYPE
direct path function context handle attribute,
A-103
function context attribute, 21-36

OCI_ATTR_DIRPATH_FLAGS
direct path loading context handle attribute,
21-16, A-96
OCI_ATTR_DIRPATH_INDEX_MAINT_METHOD
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_MODE
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_NO_INDEX_ERRORS,
21-37
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_NOLOG
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_OBJ_CONSTR, 21-35
direct path context attribute, 21-34
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_OID
direct path loading column parameter
attribute, A-107
OCI_ATTR_DIRPATH_PARALLEL, 21-1
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_PGA_LIM
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_REJECT_ROWS_REPCH
direct path loading context handle attribute,
A-96
OCI_ATTR_DIRPATH_SID
column array attribute, 21-41
direct path loading column parameter
attribute, A-107
OCI_ATTR_DIRPATH_SKIPINDEX_METHOD
direct path loading context handle attribute,
A-96
OCI_ATTR_DISTINGUISHED_NAME, 10-17
user session handle attribute, A-21
OCI_ATTR_DML_ROW_COUNT_ARRAY
statement handle attribute, A-40
OCI_ATTR_DML_ROW_OFFSET
error handle attribute, A-9
OCI_ATTR_DN_COUNT
OCIServerDNs descriptor attribute, A-83
OCI_ATTR_DRIVER_NAME, 25-32
user session handle attribute, A-21
OCI_ATTR_DURATION
attribute, 8-7
OCI_ATTR_EDITION, 17-3
user session handle attribute, A-21
OCI_ATTR_ENCAPSULATION
attribute, 8-12

Index-12

Index

OCI_ATTR_ENQ_TIME
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_ENV
server handle attribute, A-15
service context handle attribute, A-10
statement handle attribute, A-40
OCI_ATTR_ENV_CHARSET_ID
environment handle attribute, A-2
OCI_ATTR_ENV_NCHARSET_ID, 4-40
environment handle attribute, A-2
OCI_ATTR_ENV_NLS_LANGUAGE
environment handle attribute, 4-41, A-2
OCI_ATTR_ENV_NLS_TERRITORY, 4-41
environment handle attribute, A-2
OCI_ATTR_ENV_UTF16
environment handle attribute, A-2
OCI_ATTR_EVAL_CONTEXT_NAME
attribute, 8-22, 8-23
OCI_ATTR_EVAL_CONTEXT_OWNER
attribute, 8-22, 8-23
OCI_ATTR_EVALUATION_FUNCTION
attribute, 8-23
OCI_ATTR_EVENTTYPE
event handle attribute, A-113
OCI_ATTR_EVTCBK, 12-4
environment handle attribute, A-2
OCI_ATTR_EVTCTX, 12-4
environment handle attribute, A-2
OCI_ATTR_EXCEPTION_QUEUE
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_EXPIRATION
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_EXTERNAL_NAME, 10-6
server handle attribute, A-15
OCI_ATTR_FETCH_ROWID
statement handle attribute, A-40
OCI_ATTR_FIXUP_CALLBACK
authentication handle attribute, 11-4, A-20
OCI_ATTR_FOCBK
server handle attribute, A-15
session pool handle attribute, A-35
OCI_ATTR_FSPRECISION
attribute, 8-11
OCI_ATTR_HA_SOURCE
event handle attribute, A-113
OCI_ATTR_HA_SRVFIRST
event handle attribute, A-113
OCI_ATTR_HA_SRVNEXT, 12-4
event handle attribute, A-113
OCI_ATTR_HA_STATUS
event handle attribute, A-113

OCI_ATTR_HA_TIMESTAMP
event handle attribute, A-113
OCI_ATTR_HAS_DEFAULT
attribute, 8-19
OCI_ATTR_HAS_FILE
attribute, 8-9
OCI_ATTR_HAS_LOB
attribute, 8-9
OCI_ATTR_HAS_NESTED_TABLE
attribute, 8-9
OCI_ATTR_HEAPALLOC
environment handle attribute, A-2
OCI_ATTR_HOSTNAME
event handle attribute, A-113
OCI_ATTR_HW_MARK
attribute, 8-15
OCI_ATTR_IMPLICIT_RSET_COUNT, A-40
OCI_ATTR_IN_V8_MODE
server handle attribute, A-15
service context handle attribute, A-10
OCI_ATTR_INCR
attribute, 8-15
OCI_ATTR_INDEX_ONLY
attribute, 8-8
OCI_ATTR_INITIAL_CLIENT_ROLES, 10-18,
17-3
user session handle attribute, A-21
OCI_ATTR_INSTNAME, 18-6
event handle attribute, A-113
server handle attribute, A-15
service context handle attribute, A-10
shard instance descriptor attribute, A-58
OCI_ATTR_INSTSTARTTIME
event handle attribute, A-113
OCI_ATTR_INTERNAL_NAME
server handle attribute, A-15
OCI_ATTR_IOMODE
attribute, 8-19
OCI_ATTR_IS_CONSTRUCTOR
attribute, 8-12
OCI_ATTR_IS_DESTRUCTOR
attribute, 8-12
OCI_ATTR_IS_FINAL_METHOD
attribute, 8-12
OCI_ATTR_IS_FINAL_TYPE
attribute, 8-9
OCI_ATTR_IS_INCOMPLETE_TYPE
attribute, 8-9
OCI_ATTR_IS_INSTANTIABLE_METHOD
attribute, 8-12
OCI_ATTR_IS_INSTANTIABLE_TYPE
attribute, 8-9
OCI_ATTR_IS_INVOKER_RIGHTS
attribute, 8-8, 8-9

13

Index

OCI_ATTR_IS_MAP
attribute, 8-12
OCI_ATTR_IS_NULL
attribute, 8-15, 8-19
OCI_ATTR_IS_OPERATOR
attribute, 8-12
OCI_ATTR_IS_ORDER
attribute, 8-12
OCI_ATTR_IS_OVERRIDING_METHOD
attribute, 8-12
OCI_ATTR_IS_PREDEFINED_TYPE
attribute, 8-9
OCI_ATTR_IS_RECOVERABLE, A-9
OCI_ATTR_IS_RNDS
attribute, 8-12
OCI_ATTR_IS_RNPS
attribute, 8-12
OCI_ATTR_IS_SELFISH
attribute, 8-12
OCI_ATTR_IS_SUBTYPE
attribute, 8-9
OCI_ATTR_IS_SYSTEM_GENERATED_TYPE
attribute, 8-9
OCI_ATTR_IS_SYSTEM_TYPE
attribute, 8-9
OCI_ATTR_IS_TEMPORARY
attribute, 8-7
OCI_ATTR_IS_TRANSIENT_TYPE
attribute, 8-9
OCI_ATTR_IS_WNDS
attribute, 8-12
OCI_ATTR_IS_WNPS
attribute, 8-12
OCI_ATTR_LDAP_AUTH
environment handle attribute, A-2
OCI_ATTR_LDAP_CRED
environment handle attribute, A-2
OCI_ATTR_LDAP_CTX
environment handle attribute, A-2
OCI_ATTR_LDAP_HOST
environment handle attribute, A-2
OCI_ATTR_LDAP_PORT
environment handle attribute, A-2
OCI_ATTR_LEVEL
attribute, 8-19
OCI_ATTR_LFPRECISION
attribute, 8-11
OCI_ATTR_LINK
attribute, 8-14, 8-19
OCI_ATTR_LIST_ACTION_CONTEXT
attribute, 8-22
OCI_ATTR_LIST_ARGUMENTS
attribute, 8-5, 8-8, 8-12
OCI_ATTR_LIST_COLUMNS
attribute, 8-7

OCI_ATTR_LIST_COLUMNS (continued)
direct path loading
context handle attribute, A-96
function context handle attribute, A-103
OCI_ATTR_LIST_OBJECTS
attribute, 8-21
OCI_ATTR_LIST_RULES
attribute, 8-23
OCI_ATTR_LIST_SCHEMAS
attribute, 8-21
OCI_ATTR_LIST_SUBPROGRAMS
attribute, 8-9
OCI_ATTR_LIST_TABLE_ALIASES
attribute, 8-23
OCI_ATTR_LIST_TYPE
attribute, 8-20
OCI_ATTR_LIST_TYPE_ATTRS
attribute, 8-9
OCI_ATTR_LIST_TYPE_METHODS
attribute, 8-9
OCI_ATTR_LIST_VARIABLE_TYPES
attribute, 8-23
OCI_ATTR_LOB_REMOTE
LOB locator attribute, A-70
OCI_ATTR_LOB_TYPE
LOB descriptor attribute, A-70
OCI_ATTR_LOBEMPTY
LOB locator attribute, A-70
OCI_ATTR_LOBPREFETCH_LENGTH, 9-25
define handle attribute, A-54
OCI_ATTR_LOBPREFETCH_SIZE
define handle attribute, A-54
OCI_ATTR_LOCKING_MODE
attribute, 8-21
OCI_ATTR_LTXID, A-21
OCI_ATTR_MAP_METHOD
attribute, 8-9
OCI_ATTR_MAX
attribute, 8-15
OCI_ATTR_MAX_CATALOG_ NAMELEN
attribute, 8-21
OCI_ATTR_MAX_CHARSET_RATIO
service context handle attribute, A-10
OCI_ATTR_MAX_COLUMN_ NAMELEN
attribute, 8-21
OCI_ATTR_MAX_NCHARSET_RATIO
service context handle attribute, A-10
OCI_ATTR_MAX_OPEN_CURSORS, 17-3, A-21
OCI_ATTR_MAX_PROC_LEN
attribute, 8-21
OCI_ATTR_MAXCHAR_SIZE
attribute, 7-36, 7-37
bind handle attribute, A-50
define handle attribute, A-54

Index-14

Index

OCI_ATTR_MAXDATA_SIZE
attribute, 7-36
bind handle attribute, A-50
use with binding, 7-37
OCI_ATTR_MEMPOOL_APPNAME
process handle attribute, A-111
OCI_ATTR_MEMPOOL_HOMENAME
process handle attribute, A-111
OCI_ATTR_MEMPOOL_INSTNAME
process handle attribute, A-111
OCI_ATTR_MEMPOOL_SIZE
process handle attribute, A-111
OCI_ATTR_MIGSESSION
user session handle attribute, A-21
OCI_ATTR_MIN
attribute, 8-15
OCI_ATTR_MODULE, 10-25
user session handle attribute, A-21
OCI_ATTR_MSG_DELIVERY_MODE, 26-79,
26-81
OCIAQDeqOptions descriptor attribute, A-74
OCIAQEnqOptions descriptor attribute, A-73
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_MSG_PROP
notification descriptor attribute, A-93
OCI_ATTR_MSG_STATE
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_NAME
attribute, 8-8, 8-9, 8-11–8-15, 8-19, 8-24,
8-25
column array attribute, 21-39
direct path loading
column parameter attribute, A-107
context handle attribute, A-96
function context attribute, 21-35
function context handle attribute, A-103
OCI_ATTR_NAVIGATION
OCIAQDeqOptions descriptor attribute, A-74
OCI_ATTR_NCHARSET_ID
attribute, 8-21
OCI_ATTR_NFY_FLAGS
notification descriptor attribute, A-93
OCI_ATTR_NFY_MSGID
notification descriptor attribute, A-93
OCI_ATTR_NONBLOCKING_MODE
server handle attribute, 4-37, A-15
OCI_ATTR_NOWAIT_SUPPORT
attribute, 8-21
OCI_ATTR_NUM_COLS
attribute, 8-7
direct path loading
column array handle attribute, A-105
function context attribute, 21-37

OCI_ATTR_NUM_COLS (continued)
direct path loading (continued)
function context handle attribute, A-103
direct path loading context handle attribute,
A-96
OCI_ATTR_NUM_DML_ERRORS
statement handle attribute, A-40
OCI_ATTR_NUM_ELEMS
attribute, 8-13
OCI_ATTR_NUM_HANDLES attribute, 8-20
OCI_ATTR_NUM_ROWS
attribute, 21-42
direct path loading
column array handle attribute, A-105
context handle attribute, A-96
function context handle attribute, A-103
function context attribute, 21-38
OCI_ATTR_NUM_TYPE_ATTRS
attribute, 8-9
OCI_ATTR_NUM_TYPE_METHODS
attribute, 8-9
OCI_ATTR_OBJ_ID
attribute, 8-5
OCI_ATTR_OBJ_NAME
attribute, 8-5
OCI_ATTR_OBJ_SCHEMA
attribute, 8-5
OCI_ATTR_OBJECT
environment handle attribute, A-2
OCI_ATTR_OBJECT_DETECTCHANGE
environment handle attribute, 22-14, A-2
OCI_ATTR_OBJECT_NEWNOTNULL, 27-36
environment handle attribute, A-2
OCI_ATTR_OBJID
attribute, 8-7, 8-14, 8-15
OCI_ATTR_ORA_DBUG_JDWP
user session handle attribute, A-21
OCI_ATTR_ORDER
attribute, 8-15
OCI_ATTR_ORDER_METHOD
attribute, 8-9
OCI_ATTR_ORIGINAL_MSGID
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_PARAM
describe handle attribute, A-56
use when an attribute is itself a descriptor,
25-48
OCI_ATTR_PARAM_COUNT
describe handle attribute, A-56
statement handle attribute, A-40
OCI_ATTR_PARSE_ERROR_OFFSET
statement handle attribute, A-40
OCI_ATTR_PARTITIONED
attribute, 8-8

15

Index

OCI_ATTR_PASSWORD, 10-19
user session handle attribute, A-21
OCI_ATTR_PDPRC
bind handle attribute, A-50
define handle attribute, A-54
OCI_ATTR_PDSCL
bind handle attribute, A-50
define handle attribute, A-54
OCI_ATTR_PIN_DURATION
environment handle attribute, A-2
OCI_ATTR_PINOPTION
environment handle attribute, A-2
OCI_ATTR_POSITION
attribute, 8-19
OCI_ATTR_PRECISION
attribute, 8-4, 8-11, 8-13, 8-15, 8-19
direct path loading column parameter
attribute, A-107
OCI_ATTR_PREFETCH_MEMORY
statement handle attribute, A-40
OCI_ATTR_PREFETCH_ROWS
statement handle attribute, A-40
OCI_ATTR_PRIORITY
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_PROC_MODE
process handle attribute, A-111
OCI_ATTR_PROXY_CLIENT
user session handle attribute, A-21
OCI_ATTR_PROXY_CREDENTIALS, 10-16
user session handle attribute, A-21
OCI_ATTR_PTYPE
attribute, 8-5
possible values of, 8-5
OCI_ATTR_PURITY, 25-32
user session handle attribute, A-21
OCI_ATTR_QUEUE_NAME
notification descriptor attribute, A-93
OCI_ATTR_RADIX
attribute, 8-19
OCI_ATTR_RDBA
attribute, 8-8
OCI_ATTR_RECEIVE_TIMEOUT
server handle attribute, A-15
OCI_ATTR_RECIPIENT_LIST
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_REF_TDO
attribute, 8-7, 8-9, 8-11, 8-13, 8-15, 8-19
OCI_ATTR_RELATIVE_MSGID
OCIAQEnqOptions descriptor attribute, A-73
OCI_ATTR_ROW_COUNT, 6-19
direct path loading
column array handle attribute, A-105
stream handle attribute, A-106

OCI_ATTR_ROW_COUNT (continued)
statement handle attribute, A-40
OCI_ATTR_ROWID
statement handle attribute, A-40
OCI_ATTR_ROWS_FETCHED, 6-19
statement handle attribute, A-40
OCI_ATTR_ROWS_RETURNED
bind handle attribute, A-50
use with callbacks, 7-33
OCI_ATTR_SAVEPOINT_SUPPORT
attribute, 8-21
OCI_ATTR_SCALE
attribute, 8-11, 8-13, 8-15, 8-19
direct path loading column parameter
attribute, A-107
OCI_ATTR_SCHEMA_NAME
attribute, 8-9, 8-11, 8-13–8-15, 8-19
direct path loading context handle attribute,
A-96
OCI_ATTR_SEND_TIMEOUT
server handle attribute, A-15
OCI_ATTR_SENDER_ID
OCIAQMsgProperties descriptor attribute,
A-78
OCI_ATTR_SEQ
attributes, 8-15
OCI_ATTR_SEQUENCE enqueue option, 13-24
OCI_ATTR_SEQUENCE_DEVIATION
OCIAQEnqOptions descriptor attribute, A-73
OCI_ATTR_SERVER
service context handle attribute, A-10
OCI_ATTR_SERVER_DN
OCIServerDNs descriptor attribute, A-83
OCI_ATTR_SERVER_DNS
subscription handle attribute, A-83
OCI_ATTR_SERVER_GROUP, 10-14
server handle attribute, A-15
OCI_ATTR_SERVER_STATUS, 4-27
server handle attribute, A-15
OCI_ATTR_SERVICENAME
event handle attribute, A-113
OCI_ATTR_SESSION
service context handle attribute, A-10
OCI_ATTR_SESSION_STATE
user session handle attribute, A-21
OCI_ATTR_SHARD_HAS_WRITABLECHUNK
shard instance descriptor attribute, A-58
OCI_ATTR_SHARDING_KEY, 18-1, 18-5, 18-6
service context handle attribute, A-21
OCI_ATTR_SHARDING_KEY_64
service context handle attribute, A-21
OCI_ATTR_SHARED_HEAPALLOC
environment handle attribute, A-2

Index-16

Index

OCI_ATTR_SHOW_INVISIBLE_COLUMNS,
A-56
attribute, 8-35
OCI_ATTR_SODA_COLL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CONTENT
SODA document handle attributes, A-59
OCI_ATTR_SODA_CREATE_TIMESTAMP
SODA document handle attributes, A-59
OCI_ATTR_SODA_CRTIME_COL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_CACHE
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_COL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_COMPRESS
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_ENCRYPT
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_MAX_LEN
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_SQL_TYPE
SODA collection handle attribute, A-61
OCI_ATTR_SODA_CTNT_VALIDATION
SODA collection handle attribute, A-61
OCI_ATTR_SODA_DESCRIPTOR
SODA collection handle attribute, A-61
OCI_ATTR_SODA_DETECT_JSON_ENC
SODA document handle attributes, A-59
OCI_ATTR_SODA_JSON_CHARSET_ID
SODA document handle attributes, A-59
OCI_ATTR_SODA_KEY
SODA document handle attributes, A-59
OCI_ATTR_SODA_KEY_ASSIGN_METHOD
SODA collection handle attribute, A-61
OCI_ATTR_SODA_KEY_COL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_KEY_MAX_LEN
SODA collection handle attribute, A-61
OCI_ATTR_SODA_KEY_SEQ_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_KEY_SQL_TYPE
SODA collection handle attribute, A-61
OCI_ATTR_SODA_LASTMOD_TIMESTAMP
SODA document handle attributes, A-59
OCI_ATTR_SODA_MEDIA_TYPE
SODA document handle attributes, A-59
OCI_ATTR_SODA_MODTIME_COL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_MODTIME_INDEX
SODA collection handle attribute, A-61
OCI_ATTR_SODA_MTYPE_COL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_READONLY
SODA collection handle attribute, A-61

OCI_ATTR_SODA_SCHEMA
SODA collection handle attribute, A-61
OCI_ATTR_SODA_TABLE_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_VERSION
SODA document handle attributes, A-59
OCI_ATTR_SODA_VERSION_COL_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SODA_VERSION_METHOD
SODA collection handle attribute, A-61
OCI_ATTR_SODA_VIEW_NAME
SODA collection handle attribute, A-61
OCI_ATTR_SPOOL_AUTH
session pool handle attribute, 11-4, A-35
OCI_ATTR_SPOOL_BUSY_COUNT
session pool handle attribute, A-35
OCI_ATTR_SPOOL_GETMODE
session pool handle attribute, A-35
OCI_ATTR_SPOOL_INCR
session pool handle attribute, A-35
OCI_ATTR_SPOOL_MAX
session pool handle attribute, A-35
OCI_ATTR_SPOOL_MAX_LIFETIME_SESSION
session pool handle attribute, A-35
OCI_ATTR_SPOOL_MAX_USE_SESSION
session pool handle attribute, A-35
OCI_ATTR_SPOOL_MIN
session pool handle attribute, A-35
OCI_ATTR_SPOOL_OPEN_COUNT
session pool handle attribute, A-35
OCI_ATTR_SPOOL_STMTCACHESIZE
session pool handle attribute, A-35
OCI_ATTR_SPOOL_TIMEOUT
session pool handle attribute, A-35
OCI_ATTR_SPOOL_WAIT_TIMEOUT
session pool handle attribute, A-35
OCI_ATTR_SQL_ID
statement handle attribute, A-40
OCI_ATTR_SQLFNCODE
statement handle attribute, A-40
OCI_ATTR_STATEMENT
statement handle attribute, A-40
OCI_ATTR_STMT_STATE
statement handle attribute, A-40
OCI_ATTR_STMT_TYPE
statement handle attribute, A-40
OCI_ATTR_STMTCACHE_CBK
service context handle attribute, A-10
OCI_ATTR_STMTCACHE_CBKCTX
statement handle attribute, A-40
OCI_ATTR_STMTCACHESIZE, 15-3, 25-28
service context handle attribute, A-10
OCI_ATTR_STREAM_OFFSET
direct path loading stream handle attribute,
A-106

17

Index

OCI_ATTR_SUB_NAME
OCI_ATTR_TABLESPACE
attribute, 8-19
attribute, 8-8
direct path loading context handle attribute,
OCI_ATTR_TAF_ENABLED
A-96
server handle attribute, A-15
OCI_ATTR_SUBSCR_CALLBACK
OCI_ATTR_TIMESTAMP
subscription handle attribute, A-83
attribute, 8-5
OCI_ATTR_SUBSCR_CQ_QOSFLAGS
OCI_ATTR_TRANS
subscription handle attribute, A-83
service context handle attribute, A-10
OCI_ATTR_SUBSCR_CTX
OCI_ATTR_TRANS_NAME, 10-3
subscription handle attribute, A-83
transaction handle attribute, A-39
OCI_ATTR_SUBSCR_HOSTADDR
OCI_ATTR_TRANS_PROFILE_FOREIGN
subscription handle attribute, A-83
user session handle attribute, A-21
OCI_ATTR_SUBSCR_IPADDR
OCI_ATTR_TRANS_TIMEOUT
subscription handle attribute, A-83
transaction handle attribute, A-39
OCI_ATTR_SUBSCR_NAME
OCI_ATTR_TRANSACTION_IN_PROGRESS
subscription handle attribute, A-83
user session handle attribute, A-21
OCI_ATTR_SUBSCR_NAMESPACE, 13-4, 13-9
OCI_ATTR_TRANSACTION_NO
subscription handle attribute, A-83
OCIAQMsgProperties descriptor attribute,
OCI_ATTR_SUBSCR_NTFN_GROUPING_CLA
A-78
SS, A-83
OCI_ATTR_TRANSFORMATION (dequeue)
OCI_ATTR_SUBSCR_NTFN_GROUPING_REPEAT_COUNT OCIAQDeqOptions descriptor attribute, A-74
subscription handle attribute, A-83
OCI_ATTR_TRANSFORMATION (enqueue)
OCI_ATTR_SUBSCR_NTFN_GROUPING_START_TIME
OCIAQEnqOptions descriptor attribute, A-73
subscription handle attribute, A-83
OCI_ATTR_TYPE_NAME
OCI_ATTR_SUBSCR_NTFN_GROUPING_TYPE
attribute, 8-11, 8-13, 8-15, 8-19
subscription handle attribute, A-83
OCI_ATTR_TYPECODE
OCI_ATTR_SUBSCR_NTFN_GROUPING_VALUE
attribute, 8-3, 8-9, 8-11, 8-13, 8-19
subscription handle attribute, A-83
OCI_ATTR_UB8_ROW_COUNT, 6-19
OCI_ATTR_SUBSCR_PAYLOAD
statement handle attribute, A-40
subscription handle attribute, A-83
OCI_ATTR_USER_MEMORY, 12-5
OCI_ATTR_SUBSCR_PORTNO
server handle attribute, A-15
environment handle attribute, A-2
OCI_ATTR_USERNAME
OCI_ATTR_SUBSCR_QOSFLAGS
OCIAuthInfo handle attributes, A-21
subscription handle attribute, A-83
user session handle attribute, A-21
OCI_ATTR_SUBSCR_RECPT
OCI_ATTR_VALUE
subscription handle attribute, A-83
attribute, 8-25
OCI_ATTR_SUBSCR_RECPTPRES
OCI_ATTR_VARTYPE_MAXLEN_COMPAT
subscription handle attribute, A-83
service context handle attribute, A-10
OCI_ATTR_SUBSCR_RECPTPROTO
OCI_ATTR_VERSION
subscription handle attribute, A-83
attribute, 8-21
OCI_ATTR_SUBSCR_SERVER_DN
OCI_ATTR_VISIBILITY
descriptor handle, 13-9
OCIAQDeqOptions descriptor attribute, A-74
OCI_ATTR_SUBSCR_TIMEOUT
OCIAQEnqOptions descriptor attribute, A-73
subscription handle attribute, A-83
OCI_ATTR_WAIT
OCI_ATTR_SUPER_SHARDING_KEY, 18-1,
OCIAQDeqOptions descriptor attribute, A-74
18-6
OCI_ATTR_WALL_LOC
service context handle attribute, A-21
environment handle attribute, A-2
OCI_ATTR_SUPER_SHARDINGING_KEY, 18-5
OCI_ATTR_XID, 10-3
OCI_ATTR_SUPERTYPE_NAME
transaction handle attribute, A-39
attribute, 8-9
OCI_ATTR_XSTREAM_ACK_INTERVAL, 34-3
OCI_ATTR_SUPERTYPE_SCHEMA_NAME
OCI_ATTR_XSTREAM_IDLE_TIMEOUT, 34-4
attribute, 8-9
OCI_BIND_SOFT, 25-60, 25-65, 25-71, 25-76
OCI_ATTR_TABLE_NAME
OCI_CONTINUE, 4-27
attribute, 8-24
OCI_CPOOL_REINITIALIZE, 25-6
OCI_CRED_EXT, 25-28

Index-18

Index

OCI_CRED_PROXY, 10-16
OCI_CRED_RDBMS, 10-16, 25-28
OCI_DATA_AT_EXEC, 25-60, 25-65, 25-71,
25-76
OCI_DEFAULT, 10-35, 25-6, 25-15
OCI_DEFAULT mode for OCIDefineByPos(),
25-88
OCI_DEFAULT mode for OCIDefineByPos2(),
25-92
OCI_DEFINE_SOFT, 25-88, 25-92
OCI_DESCRIBE_ONLY, 26-2
OCI_DIRPATH_COL_ERROR, 21-21
OCI_DIRPATH_DATASAVE_FINISH, 26-104
OCI_DIRPATH_DATASAVE_SAVEONLY,
26-104
OCI_DIRPATH_EXPR_OBJ_CONSTR, 21-36
OCI_DIRPATH_EXPR_REF_TBLNAME, 21-25,
21-36
OCI_DIRPATH_EXPR_SQL, 21-36
OCI_DIRPATH_OID column array attribute,
21-41
OCI_DTYPE_AQAGENT, 4-12
OCI_DTYPE_AQDEQ_OPTIONS, 4-12
OCI_DTYPE_AQENQ_OPTIONS, 4-12
OCI_DTYPE_AQMSG_PROPERTIES, 4-12
OCI_DTYPE_AQNFY, 4-12
OCI_DTYPE_CHDES, 4-13
OCI_DTYPE_COMPLEXOBJECTCOMP, 4-12
OCI_DTYPE_DATE, 4-12
OCI_DTYPE_FILE, 4-12
OCI_DTYPE_INTERVAL_DS, 4-12
OCI_DTYPE_INTERVAL_YM, 4-12
OCI_DTYPE_LOB, 4-12
OCI_DTYPE_PARAM, 4-12, 25-48, 25-55
when used, 25-48
OCI_DTYPE_ROWID, 4-12
OCI_DTYPE_SHARD_KEY, 4-13
OCI_DTYPE_SNAP, 4-12
OCI_DTYPE_SRVDN, 4-12
OCI_DTYPE_TIMESTAMP, 4-12
OCI_DTYPE_TIMESTAMP_LTZ, 4-12
OCI_DTYPE_TIMESTAMP_TZ, 4-12
OCI_DURATION_DEFAULT, 27-47
OCI_DURATION_SESSION, 22-7, 26-17, 29-7,
30-3, 30-13, 30-19, 30-25
OCI_DURATION_STATEMENT, 26-17, 29-7,
30-3, 30-13, 30-18, 30-25
OCI_DURATION_TRANS, 8-7, 22-7
possible value of OCI_ATTR_DURATION,
8-7
OCI_DYNAMIC_FETCH, 25-88, 25-92
OCI_ENV_NO_MUTEX, 10-35
OCI_ERROR, 4-27, 10-7
OCI_EVENTS, 25-15
mode for receiving notifications, 13-4

OCI_FOREIGN_SYNTAX, 26-10, E-7
OCI_HTYPE_ADMIN, 4-3, 16-1
OCI_HTYPE_AUTHINFO, 4-3, 11-6
OCI_HTYPE_BIND, 4-3
OCI_HTYPE_COMPLEXOBJECT, 4-3
OCI_HTYPE_COR, 25-55
OCI_HTYPE_CPOOL, 4-3, 11-18
OCI_HTYPE_DEFINE, 4-3
OCI_HTYPE_DESCRIBE, 4-3
OCI_HTYPE_DIRPATH_COLUMN_ARRAY, 4-3
OCI_HTYPE_DIRPATH_CTX, 4-3
OCI_HTYPE_DIRPATH_FN_COL_ARRAY,
21-20, 21-38
OCI_HTYPE_DIRPATH_FN_CTX, 4-3
OCI_HTYPE_DIRPATH_STREAM, 4-3
OCI_HTYPE_ENV, 4-3
OCI_HTYPE_ERROR, 4-3
OCI_HTYPE_PROC, 4-3
OCI_HTYPE_SERVER, 4-3
OCI_HTYPE_SESSION, 4-3
OCI_HTYPE_SODA_COLLECTION, 4-3
OCI_HTYPE_SODA_CURSOR, 4-3
OCI_HTYPE_SODA_DOCUMENT, 4-3
OCI_HTYPE_SPOOL, 4-3
OCI_HTYPE_STMT, 4-3, 25-48, 25-55
OCI_HTYPE_SUBSCRIPTION, 4-3
OCI_HTYPE_SVCCTX, 4-3
OCI_HTYPE_TRANS, 4-3
OCI_IND_NULL, 19-28
OCI_INVALID_HANDLE, 4-27
OCI_IOV, 7-25, 25-88, 25-92
OCI_LOCK_NONE, 22-13
OCI_LOCK_X, 22-13
OCI_LOCK_X_NOWAIT, 22-13
parameter usage, 22-14
OCI_LOGON2_STMTCACHE, 15-2
OCI_LTYPE_ARG_FUNC list attribute, 8-20
OCI_LTYPE_ARG_PROC list attribute, 8-20
OCI_LTYPE_DB_SCH list attribute, 8-20
OCI_LTYPE_SCH_OBJ list attribute, 8-20
OCI_LTYPE_SUBPRG list attribute, 8-20
OCI_LTYPE_TYPE_ARG_FUNC list attribute,
8-20
OCI_LTYPE_TYPE_ARG_PROC list attribute,
8-20
OCI_LTYPE_TYPE_ATTR list attribute, 8-20
OCI_LTYPE_TYPE_METHOD list attribute, 8-20
OCI_MIGRATE
OCISessionBegin() mode, 10-11, 25-28
OCI_NEED_DATA, 4-27
OCI_NEW_LENGTH_SEMANTICS, 25-11
OCI_NO_DATA, 4-27
OCI_NO_UCB, 25-15
OCI_OBJECT, 25-15
OCI_PIN_ANY, 22-7

19

Index

OCI_PIN_LATEST, 22-7
OCI_PIN_RECENT, 22-7
OCI_PREP2_IMPL_RESULTS_CLIENT, E-7
OCI_PTYPE_ARG
attributes, 8-19
possible value of OCI_ATTR_PTYPE, 8-5
OCI_PTYPE_COL
attributes, 8-15
OCI_PTYPE_COLL
attributes, 8-13
OCI_PTYPE_DATABASE
attributes, 8-21
OCI_PTYPE_EVALUATION CONTEXT
attributes, 8-23
OCI_PTYPE_FUNC
attributes, 8-8
possible value of OCI_ATTR_PTYPE, 8-5
OCI_PTYPE_LIST
attributes, 8-20
OCI_PTYPE_NAME_VALUE
attributes, 8-25
OCI_PTYPE_PKG
attributes, 8-9
OCI_PTYPE_PROC
attributes, 8-8
OCI_PTYPE_RULE_SET
attributes, 8-23
OCI_PTYPE_RULES
attributes, 8-22
OCI_PTYPE_SCHEMA
attributes, 8-21
OCI_PTYPE_SYN
attributes, 8-14
OCI_PTYPE_TABLE
attributes, 8-7
OCI_PTYPE_TABLE_ALIAS
attributes, 8-24
OCI_PTYPE_TYPE
attributes, 8-9
OCI_PTYPE_TYPE_ATTR
attributes, 8-11
OCI_PTYPE_TYPE_COLL
possible value of OCI_ATTR_PTYPE, 8-5
OCI_PTYPE_TYPE_FUNC
attributes, 8-12
OCI_PTYPE_TYPE_METHOD, 8-12
OCI_PTYPE_TYPE_PROC
attributes, 8-12
OCI_PTYPE_UNK
possible value of OCI_ATTR_PTYPE, 8-5
OCI_PTYPE_VARIABLE_TYPE
attributes, 8-24
OCI_PTYPE_VIEW
attributes, 8-7
possible value of OCI_ATTR_PTYPE, 8-5

OCI_ROWCBK_DONE, 4-27
OCI_SESSGET_CUSTOM_POOL mode,
OCISessionGet(), 18-6
OCI_SESSRLS_RETAG, 25-43
OCI_STILL_EXECUTING, 4-27
OCI_SUBSCR_NAMESPACE_ANONYMOUS,
A-83
OCI_SUBSCR_PROTO_HTTP, A-83
OCI_SUBSCR_PROTO_MAIL, A-83
OCI_SUBSCR_PROTO_OCI, A-83
OCI_SUBSCR_PROTO_SERVER, A-83
OCI_SUBSCR_QOS_PURGE_ON_NTFN, 13-10
OCI_SUBSCR_QOS_RELIABLE, 13-10
OCI_SUCCESS, 4-27, 10-7
OCI_SUCCESS_WITH_INFO, 4-27
OCI_SUPPRESS_NLS_VALIDATION, 25-11,
25-15
OCI_SYSASM
OCISessionBegin() mode, 10-11, 25-28
OCI_SYSBKP
OCISessionBegin() mode, 10-11, 25-28
OCI_SYSDBA
OCISessionBegin() mode, 10-11, 25-28
OCI_SYSDGD
OCISessionBegin() mode, 10-11, 25-28
OCI_SYSKMT
OCISessionBegin() mode, 10-11, 25-28
OCI_SYSOPER
OCISessionBegin() mode, 10-11, 25-28
OCI_SYSRAC
OCISessionBegin() mode, 10-11, 25-28
OCI_THREADED, 10-35, 25-15
OCI_TRANS_LOOSE, 10-4
OCI_TRANS_NEW, 10-9
OCI_TRANS_READONLY, 10-10
OCI_TRANS_RESUME, 10-9
OCI_TRANS_SERIALIZABLE, 10-3
OCI_TRANS_TWOPHASE, 10-9
OCI_TYPECODE, 8-3
values, 5-34, 5-35
OCI_TYPECODE_ITABLE
possible value of
OCI_ATTR_COLLECTION_TYPECODE,
8-9
OCI_TYPECODE_NCHAR, 20-32
OCI_UTF16ID, 4-40
oci.lib, D-3
OCIAnyDataAccess(), 30-8
OCIAnyDataAttrGet(), 30-9
OCIAnyDataAttrSet(), 30-11
OCIAnyDataBeginCreate(), 30-13
OCIAnyDataCollAddElem(), 30-15
OCIAnyDataCollGetElem(), 30-16
OCIAnyDataConvert(), 30-18
OCIAnyDataDestroy(), 30-20

Index-20

Index

OCIAnyDataEndCreate(), 30-20
OCIAnyDataGetCurrAttrNum(), 30-21
OCIAnyDataGetType(), 30-21
OCIAnyDataIsNull(), 30-22
OCIAnyDataSetAddInstance(), 30-24
OCIAnyDataSetBeginCreate(), 30-25
OCIAnyDataSetDestroy(), 30-26
OCIAnyDataSetEndCreate(), 30-27
OCIAnyDataSetGetCount(), 30-28
OCIAnyDataSetGetInstance(), 30-28
OCIAnyDataSetGetType(), 30-29
OCIAnyDataTypeCodeToSqlt(), 20-32, 30-23
OCIAppCtxClearAll(), 25-4
OCIAppCtxSet(), 25-5
OCIAQAgent
descriptor attributes, A-82
OCIAQDeq(), 26-79
OCIAQDeqArray(), 26-81
OCIAQDeqOptions
descriptor attributes, A-74
OCIAQEnq(), 26-83
OCIAQEnqArray(), 26-85
OCIAQEnqOptions
descriptor attributes, A-73
OCIAQListen(), E-27
OCIAQListen2(), 26-87
OCIAQMsgProperties
descriptor attributes, A-78
OCIArray, 20-17
binding and defining, 20-17, 20-39
OCIArray manipulation
code example, 20-20
OCIArrayDescriptorAlloc(), 25-45
OCIArrayDescriptorFree(), 25-47
OCIAttrGet(), 17-3, 25-48
used for describing, 6-13
OCIAttrSet(), 25-49
OCIAuthInfo definition, 11-6
OCIBindArrayOfStruct(), 25-59
OCIBindByName(), 25-60
OCIBindByName2(), 25-65
OCIBindByPos(), 25-71
OCIBindByPos2(), 25-76
OCIBindDynamic(), 25-81
OCIBindObject(), 25-84
OCIBinXmlCreateReposCtxFromConn(), 32-2
OCIBinXmlCreateReposCtxFromCPool(), 32-3
OCIBinXmlSetFormatPref(), 23-6, 32-4
OCIBinXmlSetReposCtxForConn(), 32-4
OCIBreak(), 26-152
use of, 4-33, 4-38
OCICacheFlush(), 27-6
OCICacheFree(), 27-42
OCICacheRefresh(), 27-8
OCICacheUnmark(), 27-13

OCICacheUnpin(), 27-44
OCICharSetConversionIsReplacementUsed(),
31-41
OCICharSetToUnicode(), 31-42
OCIClientVersion(), 26-153
OCIColl, 20-17
binding and defining, 20-17
OCICollAppend(), 28-4
OCICollAssign(), 28-5
OCICollAssignElem(), 28-6
OCICollGetElem(), 28-7
OCICollGetElemArray(), 28-10
OCICollIsLocator(), 28-12
OCICollMax(), 28-13
OCICollSize(), 28-14
OCICollTrim(), 28-15
OCIComplexObject
use of, 19-23
OCIComplexObjectComp
use of, 19-23
OCIConnectionPoolCreate(), 25-6
OCIConnectionPoolDestroy(), 25-8
OCIContextClearValue(), 29-11
OCIContextGenerateKey(), 29-12
OCIContextGetValue(), 29-13
OCIContextSetValue(), 29-13
OCIDate, 20-5
binding and defining, 20-5, 20-39
manipulation usage example, 20-6
OCIDateAddDays(), 28-27
OCIDateAddMonths(), 28-28
OCIDateAssign(), 28-29
OCIDateCheck(), 28-29
OCIDateCompare(), 28-31
OCIDateDaysBetween(), 28-31
OCIDateFromText(), 28-32
OCIDateGetDate(), 28-33
OCIDateGetTime(), 28-34
OCIDateLastDay(), 28-35
OCIDateNextDay(), 28-36
OCIDateSetDate(), 28-37
OCIDateSetTime(), 28-37
OCIDateSysDate(), 28-38
OCIDateTimeAssign(), 28-39
OCIDateTimeCheck(), 28-39
OCIDateTimeCompare(), 28-41
OCIDateTimeConstruct(), 28-42
OCIDateTimeConvert(), 28-43
OCIDateTimeFromArray(), 28-44
OCIDateTimeFromText(), 28-45
OCIDateTimeGetDate(), 28-47
OCIDateTimeGetTime(), 28-48
OCIDateTimeGetTimeZoneName(), 28-49
OCIDateTimeGetTimeZoneOffset(), 28-50
OCIDateTimeIntervalAdd(), 28-51

21

Index

OCIDateTimeIntervalSub(), 28-51
OCIDateTimeSubtract(), 28-52
OCIDateTimeSysTimeStamp(), 28-53
OCIDateTimeToArray(), 28-54
OCIDateTimeToText(), 28-55
OCIDateToText(), 28-56
OCIDateZoneToZone(), 28-58
OCIDBShutdown(), 25-9
OCIDBStartup(), 25-10
OCIDefineArrayOfStruct(), 25-87
OCIDefineByPos(), 25-88
OCIDefineByPos2(), 25-92
OCIDefineDynamic(), 25-97
OCIDefineObject(), 25-100
OCIDescribeAny(), 25-102
limitations, 8-3
overview, 8-1
usage examples, 8-27
OCIDescriptorAlloc(), 25-50
OCIDescriptorFree(), 25-53
OCIDirPathAbort(), 26-97
OCIDirPathColArrayEntryGet(), 26-97
OCIDirPathColArrayEntrySet(), 26-99
OCIDirPathColArrayReset(), 26-100
OCIDirPathColArrayRowGet(), 26-101
OCIDirPathColArrayToStream(), 26-102
OCIDirPathDataSave(), 26-104
OCIDirPathFinish(), 26-105
OCIDirPathFlushRow(), 26-105
OCIDirPathLoadStream(), 26-106
OCIDirPathPrepare(), 26-107
OCIDirPathStreamReset(), 26-109
OCIDuration
use of, 22-7
OCIDurationBegin(), 26-17, 29-7
OCIDurationEnd(), 26-18, 29-8
OCIEnvCreate(), 25-11
OCIEnvInit(), E-2
OCIEnvNlsCreate(), 4-40, 25-15
OCIErrorGet(), 26-154
OCIEvent handle, 12-3
OCIExtProcAllocCallMemory(), 29-2
OCIExtProcGetEnv(), 29-3
OCIExtProcRaiseExcp(), 29-4
OCIExtProcRaiseExcpWithMsg(), 29-5
OCIExtractFromFile(), 29-15
OCIExtractFromList(), 29-16
OCIExtractFromStr(), 29-17
OCIExtractInit(), 29-18
OCIExtractReset(), 29-19
OCIExtractSetKey(), 29-20
OCIExtractSetNumKeys(), 29-21
OCIExtractTerm(), 29-22
OCIExtractToBool(), 29-22
OCIExtractToInt(), 29-23

OCIExtractToList(), 29-24
OCIExtractToOCINum(), 29-25
OCIExtractToStr(), 29-25
OCIFileClose(), 29-27
OCIFileExists(), 29-28
OCIFileFlush(), 29-29
OCIFileGetLength(), 29-29
OCIFileInit(), 29-30
OCIFileObject data structure, 29-26
OCIFileOpen(), 29-31
OCIFileRead(), 29-32
OCIFileSeek(), 29-33
OCIFileTerm(), 29-34
OCIFileWrite(), 29-34
OCIFormatInit(), 29-36
OCIFormatString(), 29-36
OCIFormatTerm(), 29-41
OCIHandleAlloc(), 25-53
OCIHandleFree(), 25-54
OCIInd
use of, 19-28
OCIInitialize(), E-3
OCIIntervalAdd(), 28-59
OCIIntervalAssign(), 28-60
OCIIntervalCheck(), 28-60
OCIIntervalCompare(), 28-62
OCIIntervalDivide(), 28-63
OCIIntervalFromNumber(), 28-63
OCIIntervalFromText(), 28-64
OCIIntervalFromTZ(), 28-65
OCIIntervalGetDaySecond(), 28-66
OCIIntervalGetYearMonth(), 28-67
OCIIntervalMultiply(), 28-68
OCIIntervalSetDaySecond(), 28-69
OCIIntervalSetYearMonth(), 28-70
OCIIntervalSubtract(), 28-71
OCIIntervalToNumber(), 28-72
OCIIntervalToText(), 28-72
OCIIOV struct, 7-25
OCIIter, 20-17
binding and defining, 20-17
usage example, 20-20
OCIIterCreate(), 28-16
OCIIterDelete(), 28-18
OCIIterGetCurrent(), 28-19
OCIIterInit(), 28-20
OCIIterNext(), 28-22
OCIIterPrev(), 28-23
OCILCRAttributesGet(), 35-7
OCILCRAttributesSet(), 35-9
OCILCRComparePosition(), 35-10
OCILCRConvertPosition(), 35-11
OCILCRDDLInfoGet(), 35-13
OCILCRDDLInfoSet(), 35-26
OCILCRFree(), 35-12

Index-22

Index

OCILCRGetLCRIDVersion(), 35-28
OCILCRHeaderGet(), 35-15
OCILCRHeaderSet(), 35-29
OCILCRLobInfoGet(), 35-32
OCILCRLobInfoSet(), 35-33
OCILCRNew(), 35-20
OCILCRNumberFromPosition(), 35-34
OCILCRRowColumnInfoGet(), 35-21
OCILCRRowColumnInfoSet(), 35-24
OCILCRRowStmtGet(), 35-17
OCILCRRowStmtWithBindVarGet(), 35-18
OCILCRSCNToPosition(), 35-35
OCILCRScnToPosition2(), 35-36
OCILCRWhereClauseGet(), 35-37
OCILCRWhereClauseWithBindVarGet(), 35-38
OCILdaToSvcCtx(), 26-157
OCILobAppend(), 26-19
OCILobArrayRead(), 9-25, 26-20
OCILobArrayWrite(), 26-24
OCILobAssign(), 26-28
OCILobCharSetForm(), 26-30
OCILobCharSetId(), 26-31
OCILobClose(), 26-32
OCILobCopy(), E-9
OCILobCopy2(), 26-33
OCILobCreateTemporary(), 26-35
OCILobDisableBuffering(), E-10
OCILobEnableBuffering(), E-11
OCILobErase(), E-12
OCILobErase2(), 26-37
OCILobFileClose(), 26-38
OCILobFileCloseAll(), 26-40
OCILobFileExists(), 26-40
OCILobFileGetName(), 26-42
OCILobFileIsOpen(), 26-43
OCILobFileOpen(), 26-44
OCILobFileSetName(), 26-45
OCILobFlushBuffer(), E-13
OCILobFreeTemporary(), 26-47
OCILobGetChunkSize(), 26-48
OCILobGetContentType(), 26-49
OCILobGetLength(), E-14
OCILobGetLength2(), 26-50
OCILobGetOptions(), 26-52
OCILobGetStorageLimit(), 26-53
OCILobIsEqual(), 26-54
OCILobIsOpen(), 26-55
OCILobIsTemporary(), 26-56
OCILobLoadFromFile(), E-15
OCILobLoadFromFile2(), 26-57
OCILobLocatorAssign(), 26-59
OCILobLocatorIsInit(), 26-60
OCILobOpen(), 26-62
OCILobRead(), E-15
OCILobRead2(), 26-63

OCILobSetContentType(), 26-67
OCILobSetOptions(), 26-68
OCILobTrim(), E-19
OCILobTrim2(), 26-70
OCILobWrite(), E-20
OCILobWrite2(), 26-71
OCILobWriteAppend(), E-24
OCILobWriteAppend2(), 26-75
OCILockOpt
possible values, 27-21, 27-47
OCILogoff(), 25-19
OCILogon(), 25-20
using, 4-20
OCILogon2(), 25-21
OCIMemoryAlloc(), 29-8
OCIMemoryFree(), 29-9
OCIMemoryResize(), 29-10
OCIMessageClose(), 31-46
OCIMessageGet(), 31-47
OCIMessageOpen(), 31-47
OCIMultiByteInSizeToWideChar(), 31-12
OCIMultiByteStrCaseConversion(), 31-13
OCIMultiByteStrcat(), 31-14
OCIMultiByteStrcmp(), 31-14
OCIMultiByteStrcpy(), 31-16
OCIMultiByteStrlen(), 31-16
OCIMultiByteStrncat(), 31-17
OCIMultiByteStrncmp(), 31-18
OCIMultiByteStrncpy(), 31-19
OCIMultiByteStrnDisplayLength(), 31-20
OCIMultiByteToWideChar(), 31-21
OCINlsCharSetConvert(), 31-43
OCINlsCharSetIdToName(), 31-2
OCINlsCharSetNameTold(), 31-3
OCINlsEnvironmentVariableGet(), 31-4
OCINlsGetInfo(), 31-5
OCINlsNameMap(), 31-9
OCINlsNumericInfoGet(), 31-7
OCINumber, 20-12
bind example, 20-41
binding and defining, 20-12, 20-39
define example, 20-41
usage examples, 20-12
OCINumberAbs(), 28-75
OCINumberAdd(), 28-76
OCINumberArcCos(), 28-77
OCINumberArcSin(), 28-77
OCINumberArcTan(), 28-78
OCINumberArcTan2(), 28-79
OCINumberAssign(), 28-79
OCINumberCeil(), 28-80
OCINumberCmp(), 28-81
OCINumberCos(), 28-82
OCINumberDec(), 28-82
OCINumberDiv(), 28-83

23

Index

OCINumberExp(), 28-84
OCINumberFloor(), 28-85
OCINumberFromInt(), 28-85
OCINumberFromReal(), 28-86
OCINumberFromText(), 28-87
OCINumberHypCos(), 28-88
OCINumberHypSin(), 28-89
OCINumberHypTan(), 28-90
OCINumberInc(), 28-91
OCINumberIntPower(), 28-91
OCINumberIsInt(), 28-92
OCINumberIsZero(), 28-93
OCINumberLn(), 28-93
OCINumberLog(), 28-94
OCINumberMod(), 28-95
OCINumberMul(), 28-96
OCINumberNeg(), 28-97
OCINumberPower(), 28-97
OCINumberPrec(), 28-98
OCINumberRound(), 28-99
OCINumberSetPi(), 28-100
OCINumberSetZero(), 28-100
OCINumberShift(), 28-101
OCINumberSign(), 28-101
OCINumberSin(), 28-102
OCINumberSqrt(), 28-103
OCINumberSub(), 28-104
OCINumberTan(), 28-104
OCINumberToInt(), 28-105
OCINumberToReal(), 28-106
OCINumberToRealArray(), 28-107
OCINumberToText(), 28-108
OCINumberTrunc(), 28-109
OCIObjectArrayPin(), 27-45
OCIObjectCopy(), 27-27
OCIObjectExists(), 27-20
OCIObjectFlush(), 27-10
OCIObjectFree(), 27-46
OCIObjectGetAttr(), 27-29
OCIObjectGetInd(), 27-31
example of use, 19-28
OCIObjectGetObjectRef(), 27-32
OCIObjectGetProperty(), 27-21
OCIObjectGetTypeRef(), 27-33
OCIObjectIsDirty(), 27-24
OCIObjectIsLocked(), 27-25
OCIObjectLifetime
possible values, 27-21
OCIObjectLock(), 27-34
OCIObjectLockNoWait(), 27-35
OCIObjectMarkDelete(), 27-14
OCIObjectMarkDeleteByRef(), 27-15
OCIObjectMarkStatus
possible values, 27-21
OCIObjectMarkUpdate(), 27-16

OCIObjectNew(), 27-36
OCIObjectPin(), 27-47
OCIObjectPinCountReset(), 27-50
OCIObjectPinTable(), 27-51
OCIObjectRefresh(), 27-11
OCIObjectSetAttr(), 27-40
OCIObjectUnmark(), 27-18
OCIObjectUnmarkByRef(), 27-19
OCIObjectUnpin(), 27-53
OCIParamGet(), 25-55
used for describing, 6-13
OCIParamSet(), 25-57
OCIPasswordChange(), 26-158
OCIPing(), 26-160
OCIPinOpt
use of, 22-7
OCIRaw, 20-16
binding and defining, 20-16, 20-39
manipulation usage example, 20-17
OCIRawAllocSize(), 28-110
OCIRawAssignBytes(), 28-111
OCIRawAssignRaw(), 28-112
OCIRawPtr(), 28-113
OCIRawResize(), 28-114
OCIRawSize(), 28-115
OCIRef, 20-24
binding and defining, 20-24
usage example, 20-25
OCIRefAssign(), 28-116
OCIRefClear(), 28-117
OCIRefFromHex(), 28-118
OCIRefHexSize(), 28-119
OCIRefIsEqual(), 28-120
OCIRefIsNull(), 28-121
OCIRefToHex(), 28-122
OCIRequestEnd(), 25-24
OCIReset(), 26-161
use of, 4-38
OCIRowid ROWID descriptor, 4-15
OCIRowidToChar(), 26-161
OCIServerAttach(), 25-25
shadow processes, 25-25
OCIServerDetach(), 25-27
OCIServerDNs descriptor attributes, A-83
OCIServerRelease(), 26-163
OCIServerRelease2(), 26-164
OCIServerVersion(), 26-165
OCISessionBegin(), 10-11, 25-28
OCISessionEnd(), 25-31
OCISessionGet(), 25-32
OCISessionPoolCreate(), 25-39
OCISessionPoolDestroy(), 25-42
OCISessionRelease(), 25-43
OCIShardingKeyColumnAdd(), 26-146
OCIShardingkeyReset(), 26-148

Index-24

Index

OCIShardingKeyReset(), 18-1
OCIShardInstancesGet(), 18-6, 26-148
OCISodaColl
collection handle attribute constants, 4-11
OCISodaCollCreate(), 36-2
OCISodaCollCreateWithMetadata(), 36-3
OCISodaCollDrop(), 36-8
OCISodaCollList(), 36-6
OCISodaCollOpen(), 36-4
OCISodaDoc
document handle attribute constants, 4-12
OCISodaDocCreate(), 36-9
OCISodaDocCreateWithKey(), 36-11
OCISodaDocCreateWithKeyAndMType(), 36-13
OCISodaFindOneWithKey(), 36-15
OCISodaInsert(), 36-16
OCISodaInsertAndGet(), 36-18
OCISodaInsertAndGetWithCtnt(), 36-20
OCISodaInsertWithCtnt(), 36-22
OCISodaRemoveOneWithKey(), 36-24
OCISodaReplOneAndGetWithKey(), 36-25
OCISodaReplOneWithKey(), 36-27
OCIStmtExecute(), 26-2
prefetch during, 6-7
use of iters parameter, 6-7
OCIStmtFetch(), 17-3, E-6
OCIStmtFetch2(), 17-3, 26-5
OCIStmtGetBindInfo(), 25-104
OCIStmtGetNextResult (), 26-7
OCIStmtGetPieceInfo(), 26-9
OCIStmtPrepare(), E-7
OCIStmtPrepare2(), 26-10
preparing SQL statements, 6-4
OCIStmtRelease(), 26-12
OCIStmtSetPieceInfo(), 26-13
OCIString, 20-14
binding and defining, 20-14, 20-39
manipulation usage example, 20-15
OCIStringAllocSize(), 28-124
OCIStringAssign(), 28-125
OCIStringAssignText(), 28-126
OCIStringPtr(), 28-127
OCIStringResize(), 28-128
OCIStringSize(), 28-129
OCISubscriptionDisable(), 26-89
OCISubscriptionEnable(), 26-90
OCISubscriptionPost(), 26-91
OCISubscriptionRegister(), 17-3, 26-93
OCISubscriptionUnRegister(), 17-3, 26-95
OCISvcCtxToLda(), 26-166
OCITable, 20-17
binding and defining, 20-17, 20-39
OCITableDelete(), 28-130
OCITableExists(), 28-131
OCITableFirst(), 28-132

OCITableLast(), 28-134
OCITableNext(), 28-135
OCITablePrev(), 28-136
OCITableSize(), 28-137
OCITerminate(), 25-44
OCIThread package, 10-37
OCIThreadClose(), 26-111
OCIThreadCreate(), 26-111
OCIThreadHandleGet(), 26-112
OCIThreadHndDestroy(), 26-113
OCIThreadHndInit(), 26-114
OCIThreadIdDestroy(), 26-115
OCIThreadIdGet(), 26-116
OCIThreadIdInit(), 26-117
OCIThreadIdNull(), 26-118
OCIThreadIdSame(), 26-119
OCIThreadIdSet(), 26-120
OCIThreadIdSetNull(), 26-121
OCIThreadInit(), 26-122
OCIThreadIsMulti(), 26-122
OCIThreadJoin(), 26-123
OCIThreadKeyDestroy(), 26-124
OCIThreadKeyGet(), 26-125
OCIThreadKeyInit(), 26-126
OCIThreadKeySet(), 26-127
OCIThreadMutexAcquire(), 26-127
OCIThreadMutexDestroy(), 26-128
OCIThreadMutexInit(), 26-129
OCIThreadMutexRelease(), 26-130
OCIThreadProcessInit(), 26-131
OCIThreadTerm(), 26-132
OCITransCommit(), 17-3, 26-133
OCITransDetach(), 17-3, 26-135
OCITransForget(), 17-3, 26-136
OCITransMultiPrepare(), 17-3, 26-137
OCITransPrepare(), 17-3, 26-138
OCITransRollback(), 17-3, 26-139
OCITransStart(), 17-3, 26-140
OCIType
description, 20-25
OCITypeAddAttr(), 30-2
OCITypeArrayByFullName(), 27-57
OCITypeArrayByName(), 27-55
OCITypeArrayByRef(), 27-60
OCITypeBeginCreate(), 30-3
OCITypeByName(), 27-64
OCITypeByRef(), 27-67
OCITypeCode, 5-34
OCITypeElem
description, 20-25
OCITypeEndCreate(), 30-5
OCITypeMethod
description, 20-25
OCITypePackage(), 27-68
OCITypeSetBuiltin(), 30-5

25

Index

OCITypeSetCollection(), 30-6
OCIUnicodeToCharSet(), 31-44
OCIUserCallbackGet(), 26-167
OCIUserCallbackRegister(), 26-168
OCIWchar data type, 4-44
OCIWideCharInSizeToMultiByte(), 31-22
OCIWideCharIsAlnum(), 31-35
OCIWideCharIsAlpha(), 31-35
OCIWideCharIsCntrl(), 31-36
OCIWideCharIsDigit(), 31-36
OCIWideCharIsGraph(), 31-37
OCIWideCharIsLower(), 31-37
OCIWideCharIsPrint(), 31-38
OCIWideCharIsPunct(), 31-38
OCIWideCharIsSingleByte(), 31-39
OCIWideCharIsSpace(), 31-39
OCIWideCharIsUpper(), 31-40
OCIWideCharIsXdigit(), 31-40
OCIWideCharMultiByteLength(), 31-23
OCIWideCharStrCaseConversion(), 31-23
OCIWideCharStrcat(), 31-24
OCIWideCharStrchr(), 31-25
OCIWideCharStrcmp(), 31-26
OCIWideCharStrcpy(), 31-27
OCIWideCharStrlen(), 31-27
OCIWideCharStrncat(), 31-28
OCIWideCharStrncmp(), 31-29
OCIWideCharStrncpy(), 31-30
OCIWideCharStrrchr(), 31-31
OCIWideCharToLower(), 31-32
OCIWideCharToMultiByte(), 31-33
OCIWideCharToUpper(), 31-33
ocixmldb.h header file, 23-2
OCIXmlDbFreeXmlCtx(), 32-5
OCIXmlDbInitXmlCtx(), 32-5
OCIXStreamInAttach(), 35-40
OCIXStreamInChunkSend(), 35-50
OCIXStreamInCommit(), 35-54
OCIXStreamInDetach(), 35-41
OCIXStreamInErrorGet(), 35-49
OCIXStreamInFlush(), 35-50
OCIXStreamInLCRCallbackSend(), 35-43
OCIXStreamInLCRSend(), 35-42
OCIXStreamInProcessedLWMGet(), 35-47
OCIXStreamInSessionSet(), 35-55
OCIXStreamOutAttach(), 35-56
OCIXStreamOutChunkReceive(), 35-65
OCIXStreamOutDetach(), 35-57
OCIXStreamOutGetNextChunk(), 35-68
OCIXStreamOutLCRCallbackReceive(), 35-59
OCIXStreamOutLCRReceive(), 35-58
OCIXStreamOutProcessedLWMSet(), 35-64
OCIXStreamOutSessionSet(), 35-71
ODPI-C
alternative to OCI, 1-3

ODPI-C (continued)
for Oracle Database drivers, 1-3
for user applications, 1-3
OID
See object identifiers

opaque, definition of, 1-1
optimistic locking
implementing, 22-14
ORA_NCHAR_LITERAL_REPLACE, 25-11
ORA-25219 error during enqueue, 13-24
Oracle Call Interface
See OCI

Oracle Connection Manager in Traffic Director
Mode, 11-12
Oracle data types, 5-1
mapping to C, 20-2
Oracle Database, D-4
Oracle directory structure, 3-2
Oracle ODBC Driver
for user ODBC applications, 1-3
Oracle RAC, 12-1
Oracle Real Application Clusters, 12-1
Oracle Streams Advanced Queuing
dequeue function, 26-79
description, 13-22
descriptor attributes, A-72
enqueue function, 26-83
functions, 26-78, E-26
OCI and, 13-22
OCI descriptors for, 13-23
OCI functions for, 13-23
OCI versus PL/SQL, 13-24
publish-subscribe notification in OCI, 13-2
Oracle XA Library
additional documentation, D-6
compiling and linking an OCI program, D-5
dynamic registration, D-5
Oracle XML DB OCI functions, 23-1, 32-2
oratypes.h
as parameter source in OCI, 5-37
contents, 5-37
definitions in, 5-37
ORE
See object runtime environment

OTT
See OTT utility

OTT parameters, 24-24, 24-25
CASE, 24-29
CODE, 24-27
CONFIG, 24-28
ERRTYPE, 24-28
HFILE, 24-28
INITFILE, 24-27
INITFUNC, 24-28
INTYPE, 24-26

Index-26

Index

OTT parameters (continued)
OUTTYPE, 24-27
SCHEMA_NAMES, 24-29
TRANSITIVE, 24-30
URL, 24-30
USERID, 24-26
where they appear, 24-30
OTT utility, 19-8
command line, 24-5, D-6
command-line syntax, 24-24
creating types in the database, 24-3
data type mappings, 24-9
initialization function
calling, 24-21
tasks of, 24-23
intype file, 24-31
outtype file, 24-18
overview, 24-1
parameters, 24-25
See OTT parameters, 24-25
providing an intype file, 24-8
reference, 24-23
restriction, 24-37
sample output, 19-8
use with OCI, 19-8
using, 24-1
outbound servers
OCI interface, 34-1
outtype file, 24-31
when running OTT utility, 24-18
OUTTYPE OTT parameter, 24-27

P
packages
attributes, 8-9
describing, 8-1
parameter descriptor, 4-15
attributes, 8-5, A-58
object, 20-25
parameters
attributes, 8-5
buffer lengths, 25-3
modes, 25-2
passing strings, 4-31
string length, 25-2
password management, 10-11, 10-13
persistent objects, 19-4
meta-attributes, 19-17
piecewise
binds and defines for LOBs, 7-54
fetch, 7-52
piecewise operations, 7-47
fetch, 7-45, 7-52
in PL/SQL, 7-50

piecewise operations (continued)
insert, 7-45
update, 7-45
valid data types, 7-46
pin count, 19-28
pin duration
example, 22-16
of objects, 22-15
pinning objects, 22-7
PL/SQL, 1-7
binding and defining nested tables, 7-43
binding and defining REF CURSORS, 7-43
binding placeholders, 4-38
defining output variables, 7-22
piecewise operations, 7-50
uses in OCI applications, 4-38
using in OCI applications, 4-38
using in OCI programs, 7-7
PL/SQL Callback
for session state fix up, 11-4
placeholders
rules, 6-7
pluggable databases
OCI support for, 17-1
polling mode, 4-36
positioned deletes, 4-34
positioned updates, 4-34
prefetching
during OCIStmtExecute(), 6-7
LOBs, 9-25
OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE,
9-25
setting prefetch memory size, 6-17
setting row count, 6-17
Pro*C/C++
alternative to OCI, 1-3
procedures
attributes, 8-8
process
handle attributes, A-111
proxy access, 4-21
proxy authentication, 4-21, 10-19
publish-subscribe
_SYSTEM_TRIG_ENABLED parameter,
13-15
COMPATIBLE parameter, 13-4
example, 13-15
functions, 13-4, 26-78, E-26
handle attributes, 13-4, A-83
LDAP registration, 13-9
notification callback, 13-12
notification in OCI, 13-2
subscription handle, 13-4

27

Index

Q
query, 6-16
explicit describe, 6-15
See also SQL query

R
ram_threshold, 15-15
RAW
external data type, 5-18
read-only parameter descriptor, 4-12
REF
external data type, 5-22
REF columns
direct path loading of, 21-24
REF CURSOR variables
binding and defining, 7-43
references to objects
See REFs

refreshing, 22-12
objects, 22-12
REFs, 19-10
binding, 20-34
CURSOR variables, binding, 7-17
defining, 20-37
external data type, 5-22
indicator variables for, 4-31, 4-32
retrieving from server, 19-10
registering
user callbacks, 14-1
registry
REGEDT32, D-6
relational functions, C-7
server round-trips, C-2
relinking, need for, 3-20
required support files, D-1
reserved namespaces, 4-35
reserved words, 4-35
restrictions
on OCI API calls with CDBs in general, 17-2
on OCI calls with ALTER SESSION SET
CONTAINER, 17-3
on OCI calls with ALTER SESSION SWITCH
CONTAINER SWITCH SERVICE,
17-4
result cache, 15-12
result set, 6-19
result set descriptor, 4-12
resuming branches, 10-6
retrieving attributes of an object type
example, 8-30
retrieving column data types for a table
example, 8-27

retrieving the collection element’s data type of a
named collection type
example, 8-32
return values
navigational functions, 27-4
RETURNING clause
binding with, 7-30
error handling, 7-31
initializing variables, 7-30
using with OCI, 7-29
with REFs, 7-31
rollback, 4-25
in object applications, 22-15
row change descriptor, 4-13
ROWID
external data type, 5-22
implicit fetching, 15-6
logical, 5-6
OCIRowid descriptor, 4-15
Universal ROWID, 5-6
used for positioned updates and deletes,
4-34
ROWID descriptor, 4-12
RSFs, D-1
rule sets
attributes, 8-23
type OCI_PTYPE_RULE_SET, 8-23
rules
attributes, 8-22
type OCI_PTYPE_RULE, 8-22
running OCI application, D-4

S
sample programs, B-1, D-2
samples directory, D-2
sb1
definition, 5-37
sb2
definition, 5-37
sb4
definition, 5-37
scatter/gather for binds/defines, 7-25
schema type attributes
type OCI_PTYPE_SCHEMA, 8-21
SCHEMA_NAMES OTT parameter, 24-29
usage, 24-34
schemas
attributes, 8-21–8-25
describing, 8-1
scripts
authenticating users in, 10-13
scrollable cursor
example, 6-21
in OCI, 6-19

Index-28

Index

scrollable cursor (continued)
increasing performance, 6-20
SDK for Instant Client Light, 2-7
secondary memory
of object, 22-17
SECUREFILE parameter, 9-28
SecureFiles, 9-28
OCILobGetContentType(), 26-49
OCILobSetContentType(), 26-67
SecureFiles LOBs, 9-28
security
init.ora parameters, 10-32
OCI enhancements, 10-32
select list
describing, 6-12
implicit describe, 6-12
sequences
attributes, 8-15
describing, 8-1
server handle
attributes, A-15
description, 4-6
setting in service context, 4-6
server round-trips
cache functions, C-5
data type mapping and manipulation
functions, C-6
definition of, C-1
describe operation, C-6
LOB functions, C-3
object functions, C-5
relational functions, C-7
service context handle
attributes, A-10
description, 4-6
elements of, 4-6
session creation, 4-19
session management, 10-11, 10-14
session migration, 10-11, 25-28
session pool handle
attributes, A-35
session pooling, 11-1, 11-23
example, 11-11
functionality, 11-2
runtime connection load balancing, 12-1
tagging, 11-1
shard, 18-1
Shard Instance Descriptor
attributes, A-58
shard key or group key descriptor, 4-13
sharding functions, 26-145
sharding key, 18-1
shutting down databases, 16-1
signal handler, 10-34

skip parameters
for arrays of structures, 7-23
for standard arrays, 7-24
snapshot descriptor, 4-12, 4-14
snapshots
executing against, 6-8
SODA collection handle attributes, A-61
SODA document handle attributes, A-59
SODA OCI client
character sets, 36-1
specifying a sharding key, 18-5
specifying a super sharding key, 18-5
SQL query, 6-16
binding placeholders
See bind operations, 6-16
defining output variables, 6-16, 7-17, 20-36
See define operations, 6-16
fetching results, 6-16
statement type, 1-7
SQL statements, 1-5
binding placeholders in, 6-6, 7-1, 20-33
determining type prepared, 6-4
executing, 6-7
preparing for execution, 6-4
processing, 6-1
types
control statements, 1-6
data definition language, 1-5
data manipulation language, 1-6
embedded SQL, 1-8
PL/SQL, 1-7
queries, 1-7
SQLCS_IMPLICIT, 7-34, 26-20, 26-24, 26-30,
26-35, 26-71, 26-75, E-15, E-20, E-24
SQLCS_NCHAR, 26-24, 26-30, 26-35, 26-63,
26-71, E-20, E-24
sqlnet.ora, controlling ADR, 3-28
SQLT typecodes, 5-35
SQLT_BDOUBLE, 5-28
SQLT_BFLOAT, 5-28
SQLT_CHR, A-96
SQLT_IBDOUBLE, 5-6, 8-15
SQLT_IBFLOAT, 5-6, 8-15
SQLT_NTY
bind example, 20-46
define example, 20-47
description, 5-21
preallocating object memory, 20-37
SQLT_REF
definition, 5-22
description, 5-22
starting up databases, 16-1
stateful sessions, 11-16
stateless sessions, 11-16

29

Index

statement caching, 15-1
code example, 15-6
statement handle
attributes, A-40
description, 4-8
statement_cache, 15-14
statically linked applications, 3-20
stored functions
describing, 8-1
stored procedures
describing, 8-1
STRING
external data type, 5-15
strings
passing as parameters, 4-31
structures
arrays of, 7-22
subprogram attributes, 8-8
subscription handle, 4-9
attributes, A-83
super sharding key, 18-1
supporting UTF-16 Unicode in OCI, 4-40, 4-42,
4-44, 4-45
sword
definition in oratypes.h file, 5-37
synonyms
attributes, 8-14
describing, 8-1

T
table alias
attributes
type OCI_PTYPE_TABLE_ALIAS, 8-24
table change descriptor, 4-13
tables
attributes, 8-7
describing, 8-1
limitations on OCIDescribeAny() and
OCIStmtExecute(), 8-3
TAF (transparent application failover)
callback registration, 12-11
callbacks, 12-7
connections enabled by, 12-6
in connection pools, 11-17
OCI callbacks, 12-7
TAF failover callback
structure and parameters, 12-9
tagging
custom pooling, 12-5
session pooling, 11-1, 25-32, 25-43
task thread, F-2
TDO
definition, 20-33
description, 20-25

TDO (continued)
in the object cache, 22-23
obtaining, 20-25
terminology
navigational functions, 27-3
used in this manual, 1-9
thread
dispatcher, F-2
monitor, F-2
task, F-2
thread handle description, 4-9, 10-43
thread management functions, 26-109
thread safety, 10-34
advantages of, 10-35
basic concepts, 10-34
implementing with OCI, 10-35
mixing 7.x and 8.0 calls, 10-37
required OCI calls, 10-35
three-tier architectures, 10-35
threads package, 10-37
three-tier architectures
thread safety, 10-35
time zone files differ on client and server, 3-6
TIMESTAMP data type, 5-26
TIMESTAMP descriptor, 4-12
TIMESTAMP WITH LOCAL TIME ZONE data
type, 5-27
TIMESTAMP WITH LOCAL TIME ZONE
descriptor, 4-12
TIMESTAMP WITH TIME ZONE data type, 5-26
TIMESTAMP WITH TIME ZONE descriptor, 4-12
TimesTen In-Memory Database access from
OCI, 1-1, 15-1
TNS_ADMIN, 2-6, 3-3
tnsnames.ora file, 2-3
top-level memory
of object, 22-17
Transaction Guard
logical transaction ID (LTXID), 12-14
transaction handle
attributes, A-39
description, 4-6
transaction identifier, 10-3
transaction processing monitor, D-4
additional documentation, D-6
types, D-4
transactional complexity
levels in OCI, 10-2
transactions
committing, 4-25
functions, 26-132
global, 10-3
branch states, 10-6
branches, 10-4
one-phase commit, 10-7

Index-30

Index

transactions (continued)
global (continued)
transactions identifier, 10-3
two-phase commit, 10-7
global examples, 10-8
initialization parameters, 10-8
local, 10-2
OCI functions for
transactions, 10-1
read-only, 10-3
rolling back, 4-25
serializable, 10-3
transient objects, 19-5
LOBs
attributes, 9-4
meta-attributes, 19-20
TRANSITIVE OTT parameter, 24-8, 24-12, 24-30
transparent application failover
See TAF

type attributes
attributes, 8-11
type descriptor object, 19-8, 20-25
type evolution, 19-41
object cache, 22-23
type functions
attributes, 8-12
type inheritance
OTT utility support, 24-15
type method attributes, 8-12
type procedures
attributes, 8-12
type reference, 19-33
typecodes, 5-34
types
attributes, 8-9
describing, 8-1

U
ub1
definition, 5-37
ub2
definition, 5-37
UB2MAXVAL, 25-76
ub4
definition, 5-37
UB4MAXVAL, 6-19
Unicode
character set ID, A-50, A-54
data buffer alignment, 4-45
OCILobRead(), E-15
OCILobWrite(), 26-24, 26-71, E-20
Universal ROWID, 5-6
unmarking objects, 22-10
unpinning objects, 19-28, 22-8

UNSIGNED
external data type, 5-19
updates
piecewise, 7-45, 7-47
positioned, 4-34
upgrading OCI, 3-19
URL OTT parameter, 24-30
UROWID
Universal ROWID, 5-6
user callback descriptor, 4-12
user memory
allocating, 4-17
user session handle
attributes, A-21
description, 4-6
setting in service context, 4-6
user-defined callback functions, 14-1
registering, 14-1
USERID OTT parameter, 24-26
using an explicit describe on a named collection
type
example, 8-32
using an explicit describe on a named object type
example, 8-30
using an explicit describe to retrieve column data
types for a table
example, 8-27
utext
Unicode data type, 7-36, 7-42
UTF-16 data, sample code, 7-42

V
validating format for
Oracle NUMBER and DATE data, 21-16
values, 19-4
in object applications, 19-6
VARCHAR
external data type, 5-17
VARCHAR2
external data type, 5-9
variable type attributes
type OCI_PTYPE_VARIABLE_TYPE, 8-24
VARNUM
external data type, 5-16
VARRAW
external data type, 5-18
varrays, 5-21
as objects, 19-1
C mapping, 24-11
define calls, 20-36
iterator, 28-16
NULLs, 19-28
or collection Iterator example, 20-20
scan, 28-20

31

Index

version compatibility, 3-20
views
attributes, 8-7
describing, 8-1

W
wchar_t data type, 4-44, 7-42, 31-10
with_context
argument to external procedure functions,
29-1

X
XA Library
compiling and linking an OCI program, D-5
functions, D-4

XA Library (continued)
OCI support, 1-16
overview, D-4
XA specification, 10-3
xa.h header, 1-16
XID
See transaction identifier

XML DB functions, 23-2, 32-2
XML support in OCI, 23-1, 32-1
XStream
OCI interface, 34-1
character sets, 34-2
functions, 35-1
handler and descriptor attributes, 34-3
XStream In, 34-2
XStream Out, 34-1
xtramem_sz parameter
using, 4-17

Index-32

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Author                          : Mamata BasapurRod WardD. AdamsG. AroraV. AroraA. BandeD. BanerjeeS. BanerjeeM. BastawalaE. BeldenP. BetteridgeN. BhattT. BhosleJ. BlowneyR. ChakravarthulaS. ChandrasekarB. ChengD. ChibaL. ChidambaranC. ColrainT. DasRonald DeckerA. DesaiA. DowningS. FogelT. HoangN. IkedaK. ItikarlapalliC. IyerS. IyerV. JittaC. JonesA. KehB. KhaladkarS. KrishnaswamyR. KumarR. KumarS. LahoraniS. LariT. H. LeeT. LiC. LiangI. ListvinskyJ. LiuE. LuS. LynnK.MensahV. MooreA. MullickK. NeelM. OrgiyanE. PaapanenS. PelskiR. PhillipsR. PingteR. RajamaniM. RamacherA. RamappaS. SahuA. SaxenaS. SeshadriR. SinghB. SinhaH. SlatteryJ. StewartL. SunS. SureshS. TataH. TranA. TuiningaS. VallapureddyM. VemanaS. VemuriB. VenkatakrishnanK. VermaG. ViswanathanS. WolickiL. WongS. YoussefB. Zebian
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Programmer's Guide Oracle Call Interface Programmers

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