Oracle Database Globalization Support Guide B28298Database

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Oracle® Database
Globalization Support Guide
11g Release 1 (11.1)
B28298-02
September 2007
Oracle Database Globalization Support Guide, 11g Release 1 (11.1)
B28298-02
Copyright © 1996, 2007, Oracle. All rights reserved.
Primary Author: Cathy Shea
Contributors: Dan Chiba, Winson Chu, Claire Ho, Gary Hua, Simon Law, Geoff Lee, Peter Linsley,
Qianrong Ma, Keni Matsuda, Meghna Mehta, Valarie Moore, Shige Takeda, Linus Tanaka, Makoto Tozawa,
Barry Trute, Ying Wu, Peter Wallack, Chao Wang, Huaqing Wang, Simon Wong, Michael Yau, Jianping Yang,
Qin Yu, Tim Yu, Weiran Zhang, Yan Zhu
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Contents
Preface ............................................................................................................................................................... xv
Intended Audience.................................................................................................................................... xv
Documentation Accessibility................................................................................................................... xv
Related Documentation............................................................................................................................ xvi
Conventions ............................................................................................................................................... xvi
What's New in Globalization Support?.......................................................................................... xxi
Oracle Database 11g Release 1 (11.1) New Features in Globalization............................................... xxi
Oracle Database 10g Release 2 (10.2) New Features in Globalization.............................................. xxii
1 Overview of Globalization Support
Globalization Support Architecture..................................................................................................... 1-1
Locale Data on Demand.................................................................................................................... 1-1
Architecture to Support Multilingual Applications...................................................................... 1-2
Using Unicode in a Multilingual Database .................................................................................... 1-3
Globalization Support Features ............................................................................................................ 1-4
Language Support.............................................................................................................................. 1-4
Territory Support ............................................................................................................................... 1-5
Date and Time Formats..................................................................................................................... 1-5
Monetary and Numeric Formats ..................................................................................................... 1-5
Calendar Systems............................................................................................................................... 1-5
Linguistic Sorting............................................................................................................................... 1-6
Character Set Support........................................................................................................................ 1-6
Character Semantics........................................................................................................................... 1-6
Customization of Locale and Calendar Data................................................................................. 1-6
Unicode Support ................................................................................................................................ 1-7
2 Choosing a Character Set
Character Set Encoding ........................................................................................................................... 2-1
What is an Encoded Character Set?................................................................................................. 2-1
Which Characters Are Encoded? ..................................................................................................... 2-2
Phonetic Writing Systems.......................................................................................................... 2-3
Ideographic Writing Systems.................................................................................................... 2-3
Punctuation, Control Characters, Numbers, and Symbols................................................... 2-3
Writing Direction ........................................................................................................................ 2-3
iv
What Characters Does a Character Set Support? .......................................................................... 2-3
ASCII Encoding........................................................................................................................... 2-4
How are Characters Encoded?......................................................................................................... 2-6
Single-Byte Encoding Schemes ................................................................................................. 2-7
Multibyte Encoding Schemes.................................................................................................... 2-7
Naming Convention for Oracle Database Character Sets............................................................ 2-8
Length Semantics ..................................................................................................................................... 2-8
Choosing an Oracle Database Character Set.................................................................................... 2-10
Current and Future Language Requirements............................................................................. 2-11
Client Operating System and Application Compatibility......................................................... 2-11
Character Set Conversion Between Clients and the Server ...................................................... 2-12
Performance Implications of Choosing a Database Character Set........................................... 2-12
Restrictions on Database Character Sets...................................................................................... 2-12
Restrictions on Character Sets Used to Express Names..................................................... 2-12
Database Character Set Statement of Direction.......................................................................... 2-13
Choosing Unicode as a Database Character Set ......................................................................... 2-13
Choosing a National Character Set............................................................................................... 2-14
Summary of Supported Datatypes............................................................................................... 2-14
Changing the Character Set After Database Creation.................................................................... 2-15
Monolingual Database Scenario ........................................................................................................ 2-15
Character Set Conversion in a Monolingual Scenario............................................................... 2-16
Multilingual Database Scenarios....................................................................................................... 2-17
Restricted Multilingual Support ................................................................................................... 2-17
Unrestricted Multilingual Support .............................................................................................. 2-18
3 Setting Up a Globalization Support Environment
Setting NLS Parameters .......................................................................................................................... 3-1
Choosing a Locale with the NLS_LANG Environment Variable.................................................... 3-3
Specifying the Value of NLS_LANG............................................................................................... 3-5
Overriding Language and Territory Specifications ...................................................................... 3-6
Locale Variants ................................................................................................................................... 3-6
Should the NLS_LANG Setting Match the Database Character Set?......................................... 3-7
NLS Database Parameters....................................................................................................................... 3-8
NLS Data Dictionary Views.............................................................................................................. 3-8
NLS Dynamic Performance Views.................................................................................................. 3-8
OCINlsGetInfo() Function ................................................................................................................ 3-9
Language and Territory Parameters...................................................................................................... 3-9
NLS_LANGUAGE ............................................................................................................................. 3-9
NLS_TERRITORY ........................................................................................................................... 3-11
Overriding Default Values for NLS_LANGUAGE and NLS_TERRITORY During a Session
3-13
Date and Time Parameters................................................................................................................... 3-15
Date Formats.................................................................................................................................... 3-15
NLS_DATE_FORMAT............................................................................................................ 3-15
NLS_DATE_LANGUAGE...................................................................................................... 3-16
Time Formats................................................................................................................................... 3-17
NLS_TIMESTAMP_FORMAT ............................................................................................... 3-18
v
NLS_TIMESTAMP_TZ_FORMAT ........................................................................................ 3-19
Calendar Definitions............................................................................................................................ 3-19
Calendar Formats............................................................................................................................ 3-20
First Day of the Week.............................................................................................................. 3-20
First Calendar Week of the Year............................................................................................ 3-20
Number of Days and Months in a Year................................................................................ 3-21
First Year of Era........................................................................................................................ 3-21
NLS_CALENDAR........................................................................................................................... 3-22
Numeric and List Parameters.............................................................................................................. 3-22
Numeric Formats ............................................................................................................................ 3-23
NLS_NUMERIC_CHARACTERS................................................................................................. 3-23
NLS_LIST_SEPARATOR ............................................................................................................... 3-24
Monetary Parameters............................................................................................................................ 3-24
Currency Formats ........................................................................................................................... 3-25
NLS_CURRENCY ........................................................................................................................... 3-25
NLS_ISO_CURRENCY................................................................................................................... 3-26
NLS_DUAL_CURRENCY ............................................................................................................. 3-27
Oracle Database Support for the Euro ......................................................................................... 3-27
NLS_MONETARY_CHARACTERS............................................................................................. 3-28
NLS_CREDIT................................................................................................................................... 3-28
NLS_DEBIT...................................................................................................................................... 3-29
Linguistic Sort Parameters................................................................................................................... 3-29
NLS_SORT ....................................................................................................................................... 3-29
NLS_COMP...................................................................................................................................... 3-30
Character Set Conversion Parameter................................................................................................. 3-31
NLS_NCHAR_CONV_EXCP........................................................................................................ 3-31
Length Semantics .................................................................................................................................. 3-31
NLS_LENGTH_SEMANTICS ....................................................................................................... 3-31
4 Datetime Datatypes and Time Zone Support
Overview of Datetime and Interval Datatypes and Time Zone Support...................................... 4-1
Datetime and Interval Datatypes .......................................................................................................... 4-1
Datetime Datatypes ........................................................................................................................... 4-2
DATE Datatype........................................................................................................................... 4-2
TIMESTAMP Datatype .............................................................................................................. 4-3
TIMESTAMP WITH TIME ZONE Datatype........................................................................... 4-4
TIMESTAMP WITH LOCAL TIME ZONE Datatype............................................................ 4-5
Inserting Values into Datetime Datatypes .............................................................................. 4-5
Choosing a TIMESTAMP Datatype ......................................................................................... 4-8
Interval Datatypes.............................................................................................................................. 4-9
INTERVAL YEAR TO MONTH Datatype.............................................................................. 4-9
INTERVAL DAY TO SECOND Datatype............................................................................ 4-10
Inserting Values into Interval Datatypes.............................................................................. 4-10
Datetime and Interval Arithmetic and Comparisons..................................................................... 4-10
Datetime and Interval Arithmetic................................................................................................. 4-11
Datetime Comparisons................................................................................................................... 4-11
Explicit Conversion of Datetime Datatypes................................................................................ 4-11
vi
Datetime SQL Functions...................................................................................................................... 4-12
Datetime and Time Zone Parameters and Environment Variables ............................................. 4-13
Datetime Format Parameters......................................................................................................... 4-13
Time Zone Environment Variables............................................................................................... 4-14
Daylight Saving Time Session Parameter.................................................................................... 4-14
Choosing a Time Zone File.................................................................................................................. 4-15
Upgrading the Time Zone File............................................................................................................ 4-17
DST Transition Rules Changes...................................................................................................... 4-17
Updating the Time Zone File with the utltzuv2.sql Script........................................................ 4-18
Setting the Database Time Zone ........................................................................................................ 4-21
Setting the Session Time Zone ........................................................................................................... 4-21
Converting Time Zones With the AT TIME ZONE Clause........................................................... 4-22
Support for Daylight Saving Time .................................................................................................... 4-23
Examples: The Effect of Daylight Saving Time on Datetime Calculations............................. 4-24
5 Linguistic Sorting and String Searching
Overview of Oracle Database Sorting Capabilities .......................................................................... 5-1
Using Binary Sorts ................................................................................................................................... 5-2
Using Linguistic Sorts ............................................................................................................................. 5-2
Monolingual Linguistic Sorts ........................................................................................................... 5-2
Multilingual Linguistic Sorts............................................................................................................ 5-3
Multilingual Sorting Levels .............................................................................................................. 5-4
Primary Level Sorts .................................................................................................................... 5-4
Secondary Level Sorts ................................................................................................................ 5-4
Tertiary Level Sorts..................................................................................................................... 5-4
Linguistic Sort Features........................................................................................................................... 5-5
Base Letters ......................................................................................................................................... 5-5
Ignorable Characters.......................................................................................................................... 5-6
Contracting Characters...................................................................................................................... 5-6
Expanding Characters ....................................................................................................................... 5-6
Context-Sensitive Characters............................................................................................................ 5-6
Canonical Equivalence ...................................................................................................................... 5-7
Reverse Secondary Sorting ............................................................................................................... 5-7
Character Rearrangement for Thai and Laotian Characters........................................................ 5-8
Special Letters..................................................................................................................................... 5-8
Special Combination Letters............................................................................................................. 5-8
Special Uppercase Letters................................................................................................................. 5-8
Special Lowercase Letters................................................................................................................. 5-8
Case-Insensitive and Accent-Insensitive Linguistic Sorts............................................................... 5-9
Examples of Case-Insensitive and Accent-Insensitive Sorts..................................................... 5-10
Specifying a Case-Insensitive or Accent-Insensitive Sort.......................................................... 5-11
Linguistic Sort Examples................................................................................................................ 5-12
Performing Linguistic Comparisons ................................................................................................. 5-13
Linguistic Comparison Examples................................................................................................. 5-15
Using Linguistic Indexes ..................................................................................................................... 5-17
Supported SQL Operations and Functions for Linguistic Indexes.......................................... 5-18
Linguistic Indexes for Multiple Languages................................................................................. 5-18
vii
Requirements for Using Linguistic Indexes................................................................................ 5-19
Set NLS_SORT Appropriately ............................................................................................... 5-19
Specify NOT NULL in a WHERE Clause If the Column Was Not Declared NOT NULL.......
5-19
Example: Setting Up a French Linguistic Index.................................................................. 5-19
Searching Linguistic Strings............................................................................................................... 5-20
SQL Regular Expressions in a Multilingual Environment........................................................... 5-20
Character Range '[x-y]' in Regular Expressions.......................................................................... 5-21
Collation Element Delimiter '[. .]' in Regular Expressions........................................................ 5-21
Character Class '[: :]' in Regular Expressions.............................................................................. 5-21
Equivalence Class '[= =]' in Regular Expressions....................................................................... 5-22
Examples: Regular Expressions .................................................................................................... 5-22
6 Supporting Multilingual Databases with Unicode
Overview of Unicode............................................................................................................................... 6-1
What is Unicode?...................................................................................................................................... 6-2
Supplementary Characters ............................................................................................................... 6-2
Unicode Encodings ............................................................................................................................ 6-2
UTF-8 Encoding .......................................................................................................................... 6-2
UCS-2 Encoding .......................................................................................................................... 6-3
UTF-16 Encoding ........................................................................................................................ 6-3
Examples: UTF-16, UTF-8, and UCS-2 Encoding................................................................... 6-4
Support for Unicode in Oracle Database........................................................................................ 6-4
Implementing a Unicode Solution in the Database .......................................................................... 6-5
Enabling Multilingual Support with Unicode Databases ............................................................ 6-6
Enabling Multilingual Support with Unicode Datatypes ............................................................ 6-7
How to Choose Between a Unicode Database and a Unicode Datatype Solution................... 6-8
When Should You Use a Unicode Database? ......................................................................... 6-8
When Should You Use Unicode Datatypes?........................................................................... 6-8
Comparing Unicode Character Sets for Database and Datatype Solutions .............................. 6-9
Unicode Case Studies ........................................................................................................................... 6-11
Designing Database Schemas to Support Multiple Languages................................................... 6-13
Specifying Column Lengths for Multilingual Data.................................................................... 6-13
Storing Data in Multiple Languages ............................................................................................ 6-14
Store Language Information with the Data ......................................................................... 6-14
Select Translated Data Using Fine-Grained Access Control ............................................. 6-14
Storing Documents in Multiple Languages in LOB Datatypes................................................ 6-15
Creating Indexes for Searching Multilingual Document Contents ......................................... 6-16
Creating Multilexers................................................................................................................ 6-16
Creating Indexes for Documents Stored in the CLOB Datatype ...................................... 6-17
Creating Indexes for Documents Stored in the BLOB Datatype....................................... 6-17
7 Programming with Unicode
Overview of Programming with Unicode ........................................................................................... 7-1
Database Access Product Stack and Unicode ................................................................................ 7-1
SQL and PL/SQL Programming with Unicode................................................................................... 7-3
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SQL NCHAR Datatypes.................................................................................................................... 7-4
The NCHAR Datatype ............................................................................................................... 7-4
The NVARCHAR2 Datatype..................................................................................................... 7-4
The NCLOB Datatype ................................................................................................................ 7-5
Implicit Datatype Conversion Between NCHAR and Other Datatypes.................................... 7-5
Exception Handling for Data Loss During Datatype Conversion.............................................. 7-5
Rules for Implicit Datatype Conversion......................................................................................... 7-6
SQL Functions for Unicode Datatypes............................................................................................ 7-7
Other SQL Functions ......................................................................................................................... 7-8
Unicode String Literals...................................................................................................................... 7-8
NCHAR String Literal Replacement ............................................................................................... 7-9
Using the UTL_FILE Package with NCHAR Data..................................................................... 7-10
OCI Programming with Unicode ....................................................................................................... 7-10
OCIEnvNlsCreate() Function for Unicode Programming ........................................................ 7-10
OCI Unicode Code Conversion..................................................................................................... 7-12
Data Integrity............................................................................................................................ 7-12
OCI Performance Implications When Using Unicode........................................................ 7-12
OCI Unicode Data Expansion ................................................................................................ 7-13
Setting UTF-8 to the NLS_LANG Character Set in OCI............................................................ 7-14
Binding and Defining SQL CHAR Datatypes in OCI................................................................ 7-14
Binding and Defining SQL NCHAR Datatypes in OCI............................................................. 7-15
Handling SQL NCHAR String Literals in OCI........................................................................... 7-16
Binding and Defining CLOB and NCLOB Unicode Data in OCI ............................................ 7-17
Pro*C/C++ Programming with Unicode........................................................................................... 7-17
Pro*C/C++ Data Conversion in Unicode.................................................................................... 7-18
Using the VARCHAR Datatype in Pro*C/C++.......................................................................... 7-18
Using the NVARCHAR Datatype in Pro*C/C++ ...................................................................... 7-19
Using the UVARCHAR Datatype in Pro*C/C++ ...................................................................... 7-19
JDBC Programming with Unicode..................................................................................................... 7-20
Binding and Defining Java Strings to SQL CHAR Datatypes .................................................. 7-20
Binding and Defining Java Strings to SQL NCHAR Datatypes............................................... 7-21
Using the SQL NCHAR Datatypes Without Changing the Code............................................ 7-22
Using SQL NCHAR String Literals in JDBC............................................................................... 7-22
Data Conversion in JDBC............................................................................................................... 7-23
Data Conversion for the OCI Driver..................................................................................... 7-23
Data Conversion for Thin Drivers......................................................................................... 7-23
Data Conversion for the Server-Side Internal Driver......................................................... 7-24
Using oracle.sql.CHAR in Oracle Object Types ......................................................................... 7-24
oracle.sql.CHAR....................................................................................................................... 7-24
Accessing SQL CHAR and NCHAR Attributes with oracle.sql.CHAR .......................... 7-26
Restrictions on Accessing SQL CHAR Data with JDBC............................................................ 7-26
Character Integrity Issues in a Multibyte Database Environment ................................... 7-26
ODBC and OLE DB Programming with Unicode........................................................................... 7-27
Unicode-Enabled Drivers in ODBC and OLE DB ...................................................................... 7-27
OCI Dependency in Unicode......................................................................................................... 7-28
ODBC and OLE DB Code Conversion in Unicode..................................................................... 7-28
OLE DB Code Conversions .................................................................................................... 7-29
ix
ODBC Unicode Datatypes ............................................................................................................. 7-29
OLE DB Unicode Datatypes .......................................................................................................... 7-30
ADO Access ..................................................................................................................................... 7-30
XML Programming with Unicode...................................................................................................... 7-31
Writing an XML File in Unicode with Java................................................................................. 7-31
Reading an XML File in Unicode with Java................................................................................ 7-32
Parsing an XML Stream in Unicode with Java ........................................................................... 7-32
8 Oracle Globalization Development Kit
Overview of the Oracle Globalization Development Kit ................................................................ 8-1
Designing a Global Internet Application............................................................................................ 8-2
Deploying a Monolingual Internet Application............................................................................ 8-2
Deploying a Multilingual Internet Application............................................................................. 8-4
Developing a Global Internet Application ......................................................................................... 8-5
Locale Determination ........................................................................................................................ 8-6
Locale Awareness............................................................................................................................... 8-6
Localizing the Content ...................................................................................................................... 8-7
Getting Started with the Globalization Development Kit............................................................... 8-7
GDK Quick Start...................................................................................................................................... 8-9
Modifying the HelloWorld Application ..................................................................................... 8-10
GDK Application Framework for J2EE............................................................................................. 8-16
Making the GDK Framework Available to J2EE Applications ................................................ 8-18
Integrating Locale Sources into the GDK Framework............................................................... 8-19
Getting the User Locale From the GDK Framework ................................................................. 8-20
Implementing Locale Awareness Using the GDK Localizer.................................................... 8-21
Defining the Supported Application Locales in the GDK......................................................... 8-22
Handling Non-ASCII Input and Output in the GDK Framework .......................................... 8-23
Managing Localized Content in the GDK ................................................................................... 8-25
Managing Localized Content in JSPs and Java Servlets..................................................... 8-25
Managing Localized Content in Static Files......................................................................... 8-26
GDK Java API........................................................................................................................................ 8-27
Oracle Locale Information in the GDK ........................................................................................ 8-28
Oracle Locale Mapping in the GDK ............................................................................................. 8-28
Oracle Character Set Conversion (JDK 1.4 and Later) in the GDK.......................................... 8-29
Oracle Date, Number, and Monetary Formats in the GDK...................................................... 8-30
Oracle Binary and Linguistic Sorts in the GDK.......................................................................... 8-31
Oracle Language and Character Set Detection in the GDK...................................................... 8-32
Oracle Translated Locale and Time Zone Names in the GDK ................................................. 8-33
Using the GDK with E-Mail Programs ........................................................................................ 8-34
The GDK Application Configuration File ....................................................................................... 8-35
locale-charset-maps......................................................................................................................... 8-35
page-charset ..................................................................................................................................... 8-36
application-locales........................................................................................................................... 8-36
locale-determine-rule...................................................................................................................... 8-37
locale-parameter-name................................................................................................................... 8-38
message-bundles ............................................................................................................................. 8-38
url-rewrite-rule................................................................................................................................ 8-39
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Example: GDK Application Configuration File.......................................................................... 8-40
GDK for Java Supplied Packages and Classes................................................................................ 8-41
oracle.i18n.lcsd ................................................................................................................................ 8-41
oracle.i18n.net.................................................................................................................................. 8-41
oracle.i18n.servlet............................................................................................................................ 8-42
oracle.i18n.text................................................................................................................................. 8-42
oracle.i18n.util.................................................................................................................................. 8-42
GDK for PL/SQL Supplied Packages................................................................................................ 8-42
GDK Error Messages ............................................................................................................................ 8-43
9 SQL and PL/SQL Programming in a Global Environment
Locale-Dependent SQL Functions with Optional NLS Parameters............................................... 9-1
Default Values for NLS Parameters in SQL Functions................................................................. 9-2
Specifying NLS Parameters in SQL Functions............................................................................... 9-2
Unacceptable NLS Parameters in SQL Functions ......................................................................... 9-3
Other Locale-Dependent SQL Functions ............................................................................................ 9-4
The CONVERT Function................................................................................................................... 9-4
SQL Functions for Different Length Semantics............................................................................. 9-5
LIKE Conditions for Different Length Semantics ......................................................................... 9-6
Character Set SQL Functions............................................................................................................ 9-6
Converting from Character Set Number to Character Set Name ........................................ 9-6
Converting from Character Set Name to Character Set Number ........................................ 9-6
Returning the Length of an NCHAR Column........................................................................ 9-7
The NLSSORT Function.................................................................................................................... 9-7
NLSSORT Syntax ........................................................................................................................ 9-8
Comparing Strings in a WHERE Clause ................................................................................. 9-8
Using the NLS_COMP Parameter to Simplify Comparisons in the WHERE Clause....... 9-8
Controlling an ORDER BY Clause............................................................................................ 9-9
Miscellaneous Topics for SQL and PL/SQL Programming in a Global Environment ............... 9-9
SQL Date Format Masks ................................................................................................................... 9-9
Calculating Week Numbers........................................................................................................... 9-10
SQL Numeric Format Masks......................................................................................................... 9-10
Loading External BFILE Data into LOB Columns...................................................................... 9-10
10 OCI Programming in a Global Environment
Using the OCI NLS Functions ............................................................................................................ 10-1
Specifying Character Sets in OCI ...................................................................................................... 10-2
Getting Locale Information in OCI ................................................................................................... 10-2
Mapping Locale Information Between Oracle and Other Standards ......................................... 10-3
Manipulating Strings in OCI.............................................................................................................. 10-3
Classifying Characters in OCI ............................................................................................................ 10-5
Converting Character Sets in OCI...................................................................................................... 10-5
OCI Messaging Functions ................................................................................................................... 10-6
lmsgen Utility......................................................................................................................................... 10-6
xi
11 Character Set Migration
Overview of Character Set Migration ............................................................................................... 11-1
Data Truncation............................................................................................................................... 11-1
Additional Problems Caused by Data Truncation.............................................................. 11-2
Character Set Conversion Issues................................................................................................... 11-3
Replacement Characters that Result from Using the Export and Import Utilities......... 11-3
Invalid Data That Results from Setting the Client's NLS_LANG Parameter Incorrectly ........
11-4
Conversion from Single-byte to Multibyte Character Set and Oracle Data Pump ........ 11-5
Changing the Database Character Set of an Existing Database................................................... 11-6
Migrating Character Data Using a Full Export and Import...................................................... 11-6
Migrating a Character Set Using the CSALTER Script.............................................................. 11-6
Using the CSALTER Script in an Oracle Real Application Clusters Environment........ 11-7
Migrating Character Data Using the CSALTER Script and Selective Imports ...................... 11-8
Migrating to NCHAR Datatypes........................................................................................................ 11-8
Migrating Version 8 NCHAR Columns to Oracle9i and Later................................................. 11-8
Changing the National Character Set........................................................................................... 11-9
Migrating CHAR Columns to NCHAR Columns...................................................................... 11-9
Using the ALTER TABLE MODIFY Statement to Change CHAR Columns to NCHAR
Columns 11-9
Using Online Table Redefinition to Migrate a Large Table to Unicode ........................ 11-10
Tasks to Recover Database Schema After Character Set Migration.......................................... 11-11
12 Character Set Scanner Utilities
The Language and Character Set File Scanner ................................................................................ 12-1
Syntax of the LCSSCAN Command............................................................................................. 12-2
Examples: Using the LCSSCAN Command................................................................................ 12-3
Getting Command-Line Help for the Language and Character Set File Scanner ................. 12-4
Supported Languages and Character Sets................................................................................... 12-4
LCSSCAN Error Messages............................................................................................................. 12-4
The Database Character Set Scanner................................................................................................. 12-5
Conversion Tests on Character Data............................................................................................ 12-5
Scan Modes in the Database Character Set Scanner ...................................................................... 12-6
Full Database Scan .......................................................................................................................... 12-6
User Scan .......................................................................................................................................... 12-6
Table Scan......................................................................................................................................... 12-6
Column Scan.................................................................................................................................... 12-6
Installing and Starting the Database Character Set Scanner........................................................ 12-6
Access Privileges for the Database Character Set Scanner........................................................ 12-7
Installing the Database Character Set Scanner System Tables ................................................. 12-7
Starting the Database Character Set Scanner .............................................................................. 12-7
Creating the Database Character Set Scanner Parameter File.................................................. 12-8
Getting Command-Line Help for the Database Character Set Scanner.................................. 12-8
Database Character Set Scanner Parameters.................................................................................... 12-8
Database Character Set Scanner Sessions: Examples................................................................... 12-17
Full Database Scan Examples...................................................................................................... 12-18
xii
Database Character Set Scanner Messages......................................................................... 12-18
User Scan Examples...................................................................................................................... 12-19
Database Character Set Scanner Messages......................................................................... 12-19
Single Table Scan Examples......................................................................................................... 12-19
Database Character Set Scanner Messages......................................................................... 12-20
Database Character Set Scanner Messages......................................................................... 12-21
Column Scan Examples................................................................................................................ 12-21
Database Character Set Scanner Messages......................................................................... 12-21
Database Character Set Scanner Reports........................................................................................ 12-22
Database Scan Summary Report................................................................................................. 12-22
Database Size.......................................................................................................................... 12-23
Database Scan Parameters.................................................................................................... 12-23
Scan Summary........................................................................................................................ 12-23
Data Dictionary Conversion Summary .............................................................................. 12-24
Application Data Conversion Summary ............................................................................ 12-29
Application Data Conversion Summary Per Column Size Boundary........................... 12-29
Distribution of Convertible Data Per Table ....................................................................... 12-29
Distribution of Convertible Data Per Column................................................................... 12-30
Indexes To Be Rebuilt............................................................................................................ 12-30
Truncation Due To Character Semantics............................................................................ 12-30
Character Set Detection Result............................................................................................. 12-30
Language Detection Result................................................................................................... 12-31
Database Scan Individual Exception Report............................................................................. 12-31
Database Scan Parameters.................................................................................................... 12-31
Data Dictionary Individual Exceptions .............................................................................. 12-32
Application Data Individual Exceptions............................................................................ 12-32
How to Handle Convertible or Lossy Data in the Data Dictionary .......................................... 12-33
Storage and Performance Considerations in the Database Character Set Scanner................ 12-35
Storage Considerations for the Database Character Set Scanner........................................... 12-35
CSM$TABLES......................................................................................................................... 12-35
CSM$COLUMNS................................................................................................................... 12-35
CSM$ERRORS........................................................................................................................ 12-36
Performance Considerations for the Database Character Set Scanner.................................. 12-36
Using Multiple Scan Processes............................................................................................. 12-36
Setting the Array Fetch Buffer Size ..................................................................................... 12-36
Optimizing the QUERY Clause ........................................................................................... 12-36
Suppressing Exception and Convertible Log .................................................................... 12-36
Recommendations and Restrictions for the Database Character Set Scanner...................... 12-37
Scanning Database Containing Data Not in the Database Character Set...................... 12-37
Scanning Database Containing Data from Two or More Character Sets....................... 12-37
Database Character Set Scanner CSALTER Script........................................................................ 12-37
Checking Phase of the CSALTER Script................................................................................... 12-38
Updating Phase of the CSALTER Script.................................................................................... 12-39
Database Character Set Scanner Views........................................................................................... 12-39
CSMV$COLUMNS ....................................................................................................................... 12-40
CSMV$CONSTRAINTS ............................................................................................................... 12-40
CSMV$ERRORS ............................................................................................................................ 12-41
xiii
CSMV$INDEXES........................................................................................................................... 12-41
CSMV$TABLES............................................................................................................................. 12-41
Database Character Set Scanner Error Messages .......................................................................... 12-42
13 Customizing Locale Data
Overview of the Oracle Locale Builder Utility................................................................................ 13-1
Configuring Unicode Fonts for the Oracle Locale Builder ....................................................... 13-2
Font Configuration on Windows........................................................................................... 13-2
Font Configuration on Other Platforms ............................................................................... 13-2
The Oracle Locale Builder User Interface.................................................................................... 13-3
Oracle Locale Builder Pages and Dialog Boxes .......................................................................... 13-3
Existing Definitions Dialog Box............................................................................................. 13-4
Session Log Dialog Box........................................................................................................... 13-4
Preview NLT Tab Page ........................................................................................................... 13-4
Open File Dialog Box............................................................................................................... 13-5
Creating a New Language Definition with Oracle Locale Builder ............................................. 13-6
Creating a New Territory Definition with the Oracle Locale Builder ........................................ 13-9
Customizing Time Zone Data ..................................................................................................... 13-15
Customizing Calendars with the NLS Calendar Utility.......................................................... 13-15
Displaying a Code Chart with the Oracle Locale Builder........................................................... 13-16
Creating a New Character Set Definition with the Oracle Locale Builder.............................. 13-20
Character Sets with User-Defined Characters .......................................................................... 13-20
Oracle Database Character Set Conversion Architecture........................................................ 13-21
Unicode 5.0 Private Use Area...................................................................................................... 13-21
User-Defined Character Cross-References Between Character Sets...................................... 13-22
Guidelines for Creating a New Character Set from an Existing Character Set.................... 13-22
Example: Creating a New Character Set Definition with the Oracle Locale Builder.......... 13-23
Creating a New Linguistic Sort with the Oracle Locale Builder................................................ 13-26
Changing the Sort Order for All Characters with the Same Diacritic................................... 13-29
Changing the Sort Order for One Character with a Diacritic................................................. 13-31
Generating and Installing NLB Files .............................................................................................. 13-33
Deploying Custom NLB Files on Other Platforms....................................................................... 13-34
Upgrading Custom NLB Files from Previous Releases of Oracle Database ........................... 13-35
Transporting NLB Data from One Platform to Another.............................................................. 13-35
Adding Custom Locale Definitions to Java Components with the GINSTALL Utility ....... 13-35
A Locale Data
Languages ................................................................................................................................................. A-1
Translated Messages ............................................................................................................................... A-3
Territories .................................................................................................................................................. A-4
Character Sets........................................................................................................................................... A-5
Recommended Database Character Sets ....................................................................................... A-6
Other Character Sets......................................................................................................................... A-8
Character Sets that Support the Euro Symbol ............................................................................ A-12
Client-Only Character Sets ............................................................................................................ A-14
Universal Character Sets................................................................................................................ A-15
xiv
Character Set Conversion Support ............................................................................................... A-16
Subsets and Supersets..................................................................................................................... A-16
Language and Character Set Detection Support ............................................................................. A-18
Linguistic Sorts...................................................................................................................................... A-19
Calendar Systems.................................................................................................................................. A-22
Time Zone Names.................................................................................................................................. A-23
Obsolete Locale Data............................................................................................................................ A-29
Obsolete Linguistic Sorts................................................................................................................ A-29
Obsolete Territories......................................................................................................................... A-29
Obsolete Languages........................................................................................................................ A-29
Obsolete Character Sets and Replacement Character Sets........................................................ A-29
AL24UTFFSS Character Set Desupported................................................................................... A-31
Updates to the Oracle Database Language and Territory Definition Files............................. A-31
B Unicode Character Code Assignments
Unicode Code Ranges............................................................................................................................. B-1
UTF-16 Encoding ..................................................................................................................................... B-2
UTF-8 Encoding ....................................................................................................................................... B-2
Index
xv
Preface
This book describes Oracle globalization support for Oracle Database. It explains how
to set up a globalization support environment, choose and migrate a character set,
customize locale data, do linguistic sorting, program in a global environment, and
program with Unicode.
This preface contains these topics:
■Intended Audience
■Documentation Accessibility
■Related Documentation
■Conventions
Intended Audience
Oracle Database Globalization Support Guide is intended for database administrators,
system administrators, and database application developers who perform the
following tasks:
■Set up a globalization support environment
■Choose, analyze, or migrate character sets
■Sort data linguistically
■Customize locale data
■Write programs in a global environment
■Use Unicode
To use this document, you need to be familiar with relational database concepts, basic
Oracle server concepts, and the operating system environment under which you are
running Oracle.
Documentation Accessibility
Our goal is to make Oracle products, services, and supporting documentation
accessible, with good usability, to the disabled community. To that end, our
documentation includes features that make information available to users of assistive
technology. This documentation is available in HTML format, and contains markup to
facilitate access by the disabled community. Accessibility standards will continue to
evolve over time, and Oracle is actively engaged with other market-leading
technology vendors to address technical obstacles so that our documentation can be
xvi
accessible to all of our customers. For more information, visit the Oracle Accessibility
Program Web site at
http://www.oracle.com/accessibility/
Accessibility of Code Examples in Documentation
Screen readers may not always correctly read the code examples in this document. The
conventions for writing code require that closing braces should appear on an
otherwise empty line; however, some screen readers may not always read a line of text
that consists solely of a bracket or brace.
Accessibility of Links to External Web Sites in Documentation
This documentation may contain links to Web sites of other companies or
organizations that Oracle does not own or control. Oracle neither evaluates nor makes
any representations regarding the accessibility of these Web sites.
TTY Access to Oracle Support Services
Oracle provides dedicated Text Telephone (TTY) access to Oracle Support Services
within the United States of America 24 hours a day, seven days a week. For TTY
support, call 800.446.2398.
Related Documentation
Many of the examples in this book use the sample schemas of the seed database, which
is installed by default when you install Oracle. Refer to Oracle Database Sample Schemas
for information on how these schemas were created and how you can use them
yourself.
Printed documentation is available for sale in the Oracle Store at
http://oraclestore.oracle.com/
To download free release notes, installation documentation, white papers, or other
collateral, please 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/technology/membership/
If you already have a username and password for OTN, then you can go directly to the
documentation section of the OTN Web site at
http://www.oracle.com/technology/documentation/
Conventions
This section describes the conventions used in the text and code examples of this
documentation set. It describes:
■Conventions in Text
■Conventions in Code Examples
■Conventions for Windows Operating Systems
Conventions in Text
We use various conventions in text to help you more quickly identify special terms.
The following table describes those conventions and provides examples of their use.
xvii
Conventions in Code Examples
Code examples illustrate SQL, PL/SQL, SQL*Plus, or other command-line statements.
They are displayed in a monospace (fixed-width) font and separated from normal text
as shown in this example:
SELECT username FROM dba_users WHERE username = 'MIGRATE';
The following table describes typographic conventions used in code examples and
provides examples of their use.
Convention Meaning Example
Bold Bold typeface indicates terms that are
defined in the text or terms that appear in a
glossary, or both.
When you specify this clause, you create an
index-organized table.
Italics Italic typeface indicates book titles or
emphasis. Oracle Database Concepts
Ensure that the recovery catalog and target
database do not reside on the same disk.
UPPERCASE
monospace
(fixed-width)
font
Uppercase monospace typeface indicates
elements supplied by the system. Such
elements include parameters, privileges,
datatypes, RMAN keywords, SQL
keywords, SQL*Plus or utility commands,
packages and methods, as well as
system-supplied column names, database
objects and structures, usernames, and
roles.
You can specify this clause only for a NUMBER
column.
You can back up the database by using the
BACKUP command.
Query the TABLE_NAME column in the USER_
TABLES data dictionary view.
Use the DBMS_STATS.GENERATE_STATS
procedure.
lowercase
monospace
(fixed-width)
font
Lowercase monospace typeface indicates
executables, filenames, directory names,
and sample user-supplied elements. Such
elements include computer and database
names, net service names, and connect
identifiers, as well as user-supplied
database objects and structures, column
names, packages and classes, usernames
and roles, program units, and parameter
values.
Note: Some programmatic elements use a
mixture of UPPERCASE and lowercase.
Enter these elements as shown.
Enter sqlplus to start SQL*Plus.
The password is specified in the orapwd file.
Back up the datafiles and control files in the
/disk1/oracle/dbs directory.
The department_id, department_name, and
location_id columns are in the
hr.departments table.
Set the QUERY_REWRITE_ENABLED initialization
parameter to true.
Connect as oe user.
The JRepUtil class implements these methods.
lowercase
italic
monospace
(fixed-width)
font
Lowercase italic monospace font represents
placeholders or variables. You can specify the parallel_clause.
Run old_release.SQL where old_release
refers to the release you installed prior to
upgrading.
Convention Meaning Example
[ ]
Brackets enclose one or more optional
items. Do not enter the brackets.
DECIMAL (digits [ , precision ])
{ }
Braces enclose two or more items, one of
which is required. Do not enter the braces.
{ENABLE | DISABLE}
|
A vertical bar represents a choice of two or
more options within brackets or braces.
Enter one of the options. Do not enter the
vertical bar.
{ENABLE | DISABLE}
[COMPRESS | NOCOMPRESS]
xviii
Conventions for Windows Operating Systems
The following table describes conventions for Windows operating systems and
provides examples of their use.
...
Horizontal ellipsis points indicate either:
■That we have omitted parts of the
code that are not directly related to the
example
■That you can repeat a portion of the
code
CREATE TABLE ... AS subquery;
SELECT col1, col2, ... , coln FROM
employees;
.
.
.
Vertical ellipsis points indicate that we
have omitted several lines of code not
directly related to the example.
SQL> SELECT NAME FROM V$DATAFILE;
NAME
------------------------------------
/fsl/dbs/tbs_01.dbf
/fs1/dbs/tbs_02.dbf
.
.
.
/fsl/dbs/tbs_09.dbf
9 rows selected.
Other notation You must enter symbols other than
brackets, braces, vertical bars, and ellipsis
points as shown.
acctbal NUMBER(11,2);
acct CONSTANT NUMBER(4) := 3;
Italics
Italicized text indicates placeholders or
variables for which you must supply
particular values.
CONNECT SYSTEM/system_password
DB_NAME = database_name
UPPERCASE
Uppercase typeface indicates elements
supplied by the system. We show these
terms in uppercase in order to distinguish
them from terms you define. Unless terms
appear in brackets, enter them in the order
and with the spelling shown. However,
because these terms are not case sensitive,
you can enter them in lowercase.
SELECT last_name, employee_id FROM
employees;
SELECT * FROM USER_TABLES;
DROP TABLE hr.employees;
lowercase
Lowercase typeface indicates
programmatic elements that you supply.
For example, lowercase indicates names of
tables, columns, or files.
Note: Some programmatic elements use a
mixture of UPPERCASE and lowercase.
Enter these elements as shown.
SELECT last_name, employee_id FROM
employees;
sqlplus hr/hr
CREATE USER mjones IDENTIFIED BY ty3MU9;
Convention Meaning Example
Choose Start > How to start a program. To start the Database Configuration Assistant,
choose Start > Programs > Oracle - HOME_
NAME > Configuration and Migration Tools >
Database Configuration Assistant.
Convention Meaning Example
xix
File and directory
names File and directory names are not case
sensitive. The following special characters
are not allowed: left angle bracket (<), right
angle bracket (>), colon (:), double
quotation marks ("), slash (/), pipe (|), and
dash (-). The special character backslash (\)
is treated as an element separator, even
when it appears in quotes. If the file name
begins with \\, then Windows assumes it
uses the Universal Naming Convention.
c:\winnt"\"system32 is the same as
C:\WINNT\SYSTEM32
C:\> Represents the Windows command
prompt of the current hard disk drive. The
escape character in a command prompt is
the caret (^). Your prompt reflects the
subdirectory in which you are working.
Referred to as the command prompt in this
manual.
C:\oracle\oradata>
Special characters The backslash (\) special character is
sometimes required as an escape character
for the double quotation mark (") special
character at the Windows command
prompt. Parentheses and the single
quotation mark (') do not require an escape
character. Refer to your Windows
operating system documentation for more
information on escape and special
characters.
C:\>exp scott/tiger TABLES=emp
QUERY=\"WHERE job='SALESMAN' and
sal<1600\"
C:\>imp SYSTEM/password FROMUSER=scott
TABLES=(emp, dept)
HOME_NAME
Represents the Oracle home name. The
home name can be up to 16 alphanumeric
characters. The only special character
allowed in the home name is the
underscore.
C:\> net start OracleHOME_NAMETNSListener
Convention Meaning Example
xx
ORACLE_HOME
and ORACLE_
BASE
In releases prior to Oracle8i release 8.1.3,
when you installed Oracle components, all
subdirectories were located under a top
level ORACLE_HOME directory that by
default used one of the following names:
■C:\orant for Windows NT
■C:\orawin98 for Windows 98
This release complies with Optimal
Flexible Architecture (OFA) guidelines. All
subdirectories are not under a top level
ORACLE_HOME directory. There is a top
level directory called ORACLE_BASE that
by default is C:\oracle. If you install the
latest Oracle release on a computer with no
other Oracle software installed, then the
default setting for the first Oracle home
directory is C:\oracle\orann, where nn
is the latest release number. The Oracle
home directory is located directly under
ORACLE_BASE.
All directory path examples in this guide
follow OFA conventions.
Refer to Oracle Database Platform Guide for
Windows for additional information about
OFA compliances and for information
about installing Oracle products in
non-OFA compliant directories.
Go to the ORACLE_BASE\ORACLE_
HOME\rdbms\admin directory.
Convention Meaning Example
xxi
What's New in Globalization Support?
This section describes new features of globalization support, provides pointers to
related information in this book, and contains these topics:
■Oracle Database 11g Release 1 (11.1) New Features in Globalization
■Oracle Database 10g Release 2 (10.2) New Features in Globalization
Oracle Database 11g Release 1 (11.1) New Features in Globalization
■Support for Unicode 5.0, a major version of the Unicode Standard that supercedes
all previous versions of the standard.
–1,369 new character assignments have been made to the Unicode Standard.
These additions include new characters for Cyrillic, Greek, Hebrew, Kannada,
Latin, math, phonetic extensions, symbols.
–New scripts have been added in Unicode 5.0: N'Ko, Balinese, Phags-pa,
Phoenician, Cuneiform.
–Improvements have been made in how to use characters, for example, their
properties or display algorithms.
–In addition to classifications for all of the new characters, a number of
Southeast Asian characters have been re-classified.
■Recommended Database Character Sets and Statement of Direction
A list of character sets has been compiled that Oracle strongly recommends for
usage as the database character set. For new system deployment, the database
character set is limited to this list of recommended character sets.
■Improved performance for character set conversion.
■New report section for Database Character Set Scanner that provides information
about compact binary XML (CSX) data in the Data Dictionary.
■GINSTALL utility for adding customized locale files to Java components.
See Also: Chapter 1, "Overview of Globalization Support" and
Chapter 6, "Supporting Multilingual Databases with Unicode"
See Also: Chapter 2, "Choosing a Character Set" and Appendix A,
"Locale Data"
See Also: Chapter 12, "Character Set Scanner Utilities"
xxii
■Three new languages added: Albanian, Belarusian, and Irish, and two new
territories added: Albania and Belarus.
■Linguistic index support for collation-sensitive SQL LIKE condition.
Oracle Database 10g Release 2 (10.2) New Features in Globalization
■Support for Unicode 4.0.
Unicode support has been enhanced to support the latest version of the Unicode
standard.
■Character Set Scanner Utilities Enhancements
The Database Character Set Scanner (CSSCAN) introduces two new parameters,
QUERY and COLUMN, which offer finer control in performing selective scanning.
Support for multilevel varrays and nested tables has also been added.
The Language and Character Set File Scanner (LCSSCAN) now supports the
detection of HTML files. The detection quality of shorter text strings has also been
enhanced.
■Globalization Development Kit
The Globalization Development Kit (GDK) for PL/SQL provides new locale
mapping functions, and offers support for Japanese Kana conversion using the
new transliteration function in the UTL_I18N package.
■NCHAR String Literal Support
SQL NCHAR literals used in insert and update statements no longer rely on the
database character set for conversion. This means that multilingual data can be
added without restrictions such as having to provide hex Unicode values. The
support for this feature is available in SQL, PL/SQL, OCI, and JDBC.
■Consistent Linguistic Ordering Support
The support for all SQL functions and operators to honor the NLS_SORT setting is
now available using the new NLS_COMP mode LINGUISTIC. This feature ensures
all SQL string comparisons are consistent, and that they follow the linguistic
convention as specified in the NLS_SORT parameter.
See Also: Chapter 13, "Customizing Locale Data"
See Also: Appendix A, "Locale Data"
See Also: Chapter 5, "Linguistic Sorting and String Searching"
See Also: Chapter 6, "Supporting Multilingual Databases with
Unicode"
See Also: Chapter 12, "Character Set Scanner Utilities"
See Also: Chapter 8, "Oracle Globalization Development Kit"
See Also: "NCHAR String Literal Replacement" in Chapter 7,
"Programming with Unicode"
xxiii
See Also: Chapter 5, "Linguistic Sorting and String Searching"
xxiv
Overview of Globalization Support 1-1
1
Overview of Globalization Support
This chapter provides an overview of globalization support for Oracle Database. This
chapter discusses the following topics:
■Globalization Support Architecture
■Globalization Support Features
Globalization Support Architecture
The globalization support in Oracle Database enables you to store, process, and
retrieve data in native languages. It ensures that database utilities, error messages, sort
order, and date, time, monetary, numeric, and calendar conventions automatically
adapt to any native language and locale.
In the past, Oracle referred to globalization support capabilities as National Language
Support (NLS) features. NLS is actually a subset of globalization support. NLS is the
ability to choose a national language and store data in a specific character set.
Globalization support enables you to develop multilingual applications and software
products that can be accessed and run from anywhere in the world simultaneously. An
application can render content of the user interface and process data in the native
users' languages and locale preferences.
Locale Data on Demand
Oracle Database globalization support is implemented with the Oracle NLS Runtime
Library (NLSRTL). The NLS RTL provides a comprehensive suite of
language-independent functions that perform proper text and character processing
and language-convention manipulations. Behavior of these functions for a specific
language and territory is governed by a set of locale-specific data that is identified and
loaded at runtime.
The locale-specific data is structured as independent sets of data for each locale that
Oracle Database supports. The data for a particular locale can be loaded
independently of other locale data.
The advantages of this design are as follows:
■You can manage memory consumption by choosing the set of locales that you
need.
■You can add and customize locale data for a specific locale without affecting other
locales.
Globalization Support Architecture
1-2 Oracle Database Globalization Support Guide
Figure 1–1 shows how locale-specific data is loaded at runtime. In this example,
French data and Japanese data are loaded into the multilingual database, but German
data is not.
Figure 1–1 Loading Locale-Specific Data to the Database
The locale-specific data is stored in the $ORACLE_HOME/nls/data directory. The
ORA_NLS10 environment variable should be defined only when you need to change
the default directory location for the locale-specific datafiles, for example, when the
system has multiple Oracle Database homes that share a single copy of the
locale-specific datafiles.
A boot file is used to determine the availability of the NLS objects that can be loaded.
Oracle Database supports both system and user boot files. The user boot file gives you
the flexibility to tailor what NLS locale objects are available for the database. Also, new
locale data can be added and some locale data components can be customized.
Architecture to Support Multilingual Applications
Oracle Database enables multitier applications and client/server applications to
support languages for which the database is configured.
The locale-dependent operations are controlled by several parameters and
environment variables on both the client and the database server. On the database
server, each session that is started on behalf of a client may run in the same or a
different locale as other sessions, and can have the same or different language
requirements specified.
Oracle Database has a set of session-independent NLS parameters that are specified
when you create a database. Two of the parameters specify the database character set
and the national character set, which is an alternative Unicode character set that can be
specified for NCHAR, NVARCHAR2, and NCLOB data. The parameters specify the
character set that is used to store text data in the database. Other parameters, such as
language and territory, are used to evaluate and check constraints.
If the client session and the database server specify different character sets, then the
database converts character set strings automatically.
See Also: Chapter 13, "Customizing Locale Data"
Multilingual
Database
French
Data
Japanese
Data
French
Data
German
Data
Japanese
Data
Globalization Support Architecture
Overview of Globalization Support 1-3
From a globalization support perspective, all applications are considered to be clients,
even if they run on the same physical machine as the Oracle Database instance. For
example, when SQL*Plus is started by the UNIX user who owns the Oracle Database
software from the Oracle home in which the RDBMS software is installed, and
SQL*Plus connects to the database through an adapter by specifying the ORACLE_SID
parameter, SQL*Plus is considered a client. Its behavior is ruled by client-side NLS
parameters.
Another example of an application being considered a client occurs when the middle
tier is an application server. The different sessions spawned by the application server
are considered to be separate client sessions.
When a client application is started, it initializes the client NLS environment from
environment settings. All NLS operations performed locally are executed using these
settings. Examples of local NLS operations are:
■Display formatting in Oracle Developer applications
■User OCI code that executes NLS OCI functions with OCI environment handles
When the application connects to a database, a session is created on the server. The
new session initializes its NLS environment from NLS instance parameters specified in
the initialization parameter file. These settings can be subsequently changed by an
ALTER SESSION statement. The statement changes only the session NLS environment.
It does not change the local client NLS environment. The session NLS settings are used
to process SQL and PL/SQL statements that are executed on the server. For example,
use an ALTER SESSION statement to set the NLS_LANGUAGE initialization parameter
to Italian:
ALTER SESSION SET NLS_LANGUAGE=Italian;
Enter a SELECT statement:
SQL> SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees;
You should see results similar to the following:
LAST_NAME HIRE_DATE SALARY
------------------------- --------- ----------
Sciarra 30-SET-97 962.5
Urman 07-MAR-98 975
Popp 07-DIC-99 862.5
Note that the month name abbreviations are in Italian.
Immediately after the connection has been established, if the NLS_LANG environment
setting is defined on the client side, then an implicit ALTER SESSION statement
synchronizes the client and session NLS environments.
Using Unicode in a Multilingual Database
Unicode, the universal encoded character set, enables you to store information in any
language by using a single character set. Unicode provides a unique code value for
every character, regardless of the platform, program, or language.
Unicode has the following advantages:
See Also:
■Chapter 10, "OCI Programming in a Global Environment"
■Chapter 3, "Setting Up a Globalization Support Environment"
Globalization Support Features
1-4 Oracle Database Globalization Support Guide
■Simplifies character set conversion and linguistic sort functions.
■Improves performance compared with native multibyte character sets.
■Supports the Unicode datatype based on the Unicode standard.
Globalization Support Features
This section provides an overview of the standard globalization features in Oracle
Database:
■Language Support
■Territory Support
■Date and Time Formats
■Monetary and Numeric Formats
■Calendar Systems
■Linguistic Sorting
■Character Set Support
■Character Semantics
■Customization of Locale and Calendar Data
■Unicode Support
Language Support
Oracle Database enables you to store, process, and retrieve data in native languages.
The languages that can be stored in a database are all languages written in scripts that
are encoded by Oracle-supported character sets. Through the use of Unicode
databases and datatypes, Oracle Database supports most contemporary languages.
Additional support is available for a subset of the languages. The database can, for
example, display dates using translated month names, and can sort text data according
to cultural conventions.
When this document uses the term language support, it refers to the additional
language-dependent functionality, and not to the ability to store text of a specific
language. For example, language support includes displaying dates or sorting text
according to specific locales and cultural conventions. Additionally, for some of the
supported languages, Oracle Database provides translated error messages and a
translated user interface for the database utilities.
See Also:
■Chapter 6, "Supporting Multilingual Databases with Unicode"
■Chapter 7, "Programming with Unicode"
■"Enabling Multilingual Support with Unicode Datatypes" on
page 6-7
Globalization Support Features
Overview of Globalization Support 1-5
Territory Support
Oracle Database supports cultural conventions that are specific to geographical
locations. The default local time format, date format, and numeric and monetary
conventions depend on the local territory setting. Setting different NLS parameters
enables the database session to use different cultural settings. For example, you can set
the euro (EUR) as the primary currency and the Japanese yen (JPY) as the secondary
currency for a given database session, even when the territory is defined as AMERICA.
Date and Time Formats
Different conventions for displaying the hour, day, month, and year can be handled in
local formats. For example, in the United Kingdom, the date is displayed using the
DD-MON-YYYY format, while Japan commonly uses the YYYY-MM-DD format.
Time zones and daylight saving support are also available.
Monetary and Numeric Formats
Currency, credit, and debit symbols can be represented in local formats. Radix symbols
and thousands separators can be defined by locales. For example, in the US, the
decimal point is a dot (.), while it is a comma (,) in France. Therefore, the amount
$1,234 has different meanings in different countries.
Calendar Systems
Many different calendar systems are in use around the world. Oracle Database
supports seven different calendar systems:
■Gregorian
■Japanese Imperial
See Also:
■Chapter 3, "Setting Up a Globalization Support Environment"
■"Languages" on page A-1 for a complete list of Oracle Database
language names and abbreviations
■"Translated Messages" on page A-3 for a list of languages into
which Oracle Database messages are translated
See Also:
■Chapter 3, "Setting Up a Globalization Support Environment"
■"Territories" on page A-4 for a list of territories that are
supported by Oracle Database
See Also:
■Chapter 3, "Setting Up a Globalization Support Environment"
■Chapter 4, "Datetime Datatypes and Time Zone Support"
■Oracle Database SQL Reference
See Also: Chapter 3, "Setting Up a Globalization Support
Environment"
Globalization Support Features
1-6 Oracle Database Globalization Support Guide
■ROC Official (Republic of China)
■ Thai Buddha
■Persian
■English Hijrah
■Arabic Hijrah
Linguistic Sorting
Oracle Database provides linguistic definitions for culturally accurate sorting and case
conversion. The basic definition treats strings as sequences of independent characters.
The extended definition recognizes pairs of characters that should be treated as special
cases.
Strings that are converted to upper case or lower case using the basic definition always
retain their lengths. Strings converted using the extended definition may become
longer or shorter.
Character Set Support
Oracle Database supports a large number of single-byte, multibyte, and fixed-width
encoding schemes that are based on national, international, and vendor-specific
standards.
Character Semantics
Oracle Database provides character semantics. It is useful for defining the storage
requirements for multibyte strings of varying widths in terms of characters instead of
bytes.
Customization of Locale and Calendar Data
You can customize locale data such as language, character set, territory, or linguistic
sort using the Oracle Locale Builder.
You can customize calendars with the NLS Calendar Utility.
See Also:
■Chapter 3, "Setting Up a Globalization Support Environment"
■"Calendar Systems" on page A-22 for more information about
supported calendars
See Also: Chapter 5, "Linguistic Sorting and String Searching"
See Also:
■Chapter 2, "Choosing a Character Set"
■"Character Sets" on page A-5 for a list of supported character
sets
See Also: "Length Semantics" on page 2-8
Globalization Support Features
Overview of Globalization Support 1-7
Unicode Support
Unicode is an industry standard that enables text and symbols from all languages to
be consistently represented and manipulated by computers. The latest version of the
Unicode standard, as of this release, is 5.0.
Oracle Database has complied with the Unicode standard since Oracle 7. Subsequently,
Oracle Database 10g release 2 supports Unicode 4.0. Oracle Database 11g release 1
supports Unicode 5.0.
You can store Unicode characters in an Oracle database in two ways:
■You can create a Unicode database that enables you to store UTF-8 encoded
characters as SQL CHAR datatypes.
■You can support multilingual data in specific columns by using Unicode
datatypes. You can store Unicode characters into columns of the SQL NCHAR
datatypes regardless of how the database character set has been defined. The
NCHAR datatype is an exclusively Unicode datatype.
See Also:
■Chapter 13, "Customizing Locale Data"
■"Customizing Calendars with the NLS Calendar Utility" on
page 13-15
See Also: Chapter 6, "Supporting Multilingual Databases with
Unicode"
Globalization Support Features
1-8 Oracle Database Globalization Support Guide
Choosing a Character Set 2-1
2
Choosing a Character Set
This chapter explains how to choose a character set. The following topics are included:
■Character Set Encoding
■Length Semantics
■Choosing an Oracle Database Character Set
■Changing the Character Set After Database Creation
■Monolingual Database Scenario
■Multilingual Database Scenarios
Character Set Encoding
When computer systems process characters, they use numeric codes instead of the
graphical representation of the character. For example, when the database stores the
letter A, it actually stores a numeric code that the computer system interprets as the
letter. These numeric codes are especially important in a global environment because
of the potential need to convert data between different character sets.
This section discusses the following topics:
■What is an Encoded Character Set?
■Which Characters Are Encoded?
■What Characters Does a Character Set Support?
■How are Characters Encoded?
■Naming Convention for Oracle Database Character Sets
What is an Encoded Character Set?
You specify an encoded character set when you create a database. Choosing a
character set determines what languages can be represented in the database. It also
affects:
■How you create the database schema
■How you develop applications that process character data
■How the database works with the operating system
■Database performance
■Storage required for storing character data
Character Set Encoding
2-2 Oracle Database Globalization Support Guide
A group of characters (for example, alphabetic characters, ideographs, symbols,
punctuation marks, and control characters) can be encoded as a character set. An
encoded character set assigns a unique numeric code to each character in the character
set. The numeric codes are called code points or encoded values. Table 2–1 shows
examples of characters that have been assigned a hexadecimal code value in the ASCII
character set.
The computer industry uses many encoded character sets. Character sets differ in the
following ways:
■The number of characters available to be used in the set
■The characters that are available to be used in the set (also known as the character
repertoire)
■The scripts used for writing and the languages that they represent
■The code points or values assigned to each character
■The encoding scheme used to represent a specific character
Oracle Database supports most national, international, and vendor-specific encoded
character set standards.
Which Characters Are Encoded?
The characters that are encoded in a character set depend on the writing systems that
are represented. A writing system can be used to represent a language or a group of
languages. Writing systems can be classified into two categories:
■Phonetic Writing Systems
■Ideographic Writing Systems
This section also includes the following topics:
■Punctuation, Control Characters, Numbers, and Symbols
■Writing Direction
Table 2–1 Encoded Characters in the ASCII Character Set
Character Description Hexadecimal Code Value
!Exclamation Mark21
#Number Sign23
$Dollar Sign 24
1Number 1 31
2Number 2 32
3Number 3 33
A Uppercase A 41
B Uppercase B 42
C Uppercase C 43
aLowercase a 61
bLowercase b 62
cLowercase c 63
See Also: "Character Sets" on page A-5 for a complete list of
character sets that are supported by Oracle Database
Character Set Encoding
Choosing a Character Set 2-3
Phonetic Writing Systems
Phonetic writing systems consist of symbols that represent different sounds associated
with a language. Greek, Latin, Cyrillic, and Devanagari are all examples of phonetic
writing systems based on alphabets. Note that alphabets can represent more than one
language. For example, the Latin alphabet can represent many Western European
languages such as French, German, and English.
Characters associated with a phonetic writing system can typically be encoded in one
byte because the character repertoire is usually smaller than 256 characters.
Ideographic Writing Systems
Ideographic writing systems consist of ideographs or pictographs that represent the
meaning of a word, not the sounds of a language. Chinese and Japanese are examples
of ideographic writing systems that are based on tens of thousands of ideographs.
Languages that use ideographic writing systems may also use a syllabary. Syllabaries
provide a mechanism for communicating additional phonetic information. For
instance, Japanese has two syllabaries: Hiragana, normally used for grammatical
elements, and Katakana, normally used for foreign and onomatopoeic words.
Characters associated with an ideographic writing system typically are encoded in
more than one byte because the character repertoire has tens of thousands of
characters.
Punctuation, Control Characters, Numbers, and Symbols
In addition to encoding the script of a language, other special characters need to be
encoded:
■Punctuation marks such as commas, periods, and apostrophes
■Numbers
■Special symbols such as currency symbols and math operators
■Control characters such as carriage returns and tabs
Writing Direction
Most Western languages are written left to right from the top to the bottom of the
page. East Asian languages are usually written top to bottom from the right to the left
of the page, although exceptions are frequently made for technical books translated
from Western languages. Arabic and Hebrew are written right to left from the top to
the bottom.
Numbers reverse direction in Arabic and Hebrew. Although the text is written right to
left, numbers within the sentence are written left to right. For example, "I wrote 32
books" would be written as "skoob 32 etorw I". Regardless of the writing direction,
Oracle Database stores the data in logical order. Logical order means the order that is
used by someone typing a language, not how it looks on the screen.
Writing direction does not affect the encoding of a character.
What Characters Does a Character Set Support?
Different character sets support different character repertoires. Because character sets
are typically based on a particular writing script, they can support more than one
language. When character sets were first developed, they had a limited character
repertoire. Even now there can be problems using certain characters across platforms.
Character Set Encoding
2-4 Oracle Database Globalization Support Guide
The following CHAR and VARCHAR characters are represented in all Oracle Database
character sets and can be transported to any platform:
■Uppercase and lowercase English characters A through Z and a through z
■Arabic digits 0 through 9
■The following punctuation marks: % ‘ ' ( ) * + - , . / \ : ; < > = ! _ & ~ { } | ^ ? $ # @ "
[ ]
■The following control characters: space, horizontal tab, vertical tab, form feed
If you are using characters outside this set, then take care that your data is supported
in the database character set that you have chosen.
Setting the NLS_LANG parameter properly is essential to proper data conversion. The
character set that is specified by the NLS_LANG parameter should reflect the setting for
the client operating system. Setting NLS_LANG correctly enables proper conversion
from the client operating system character encoding to the database character set.
When these settings are the same, Oracle Database assumes that the data being sent or
received is encoded in the same character set as the database character set, so character
set validation or conversion may not be performed. This can lead to corrupt data if
conversions are necessary.
During conversion from one character set to another, Oracle Database expects
client-side data to be encoded in the character set specified by the NLS_LANG
parameter. If you put other values into the string (for example, by using the CHR or
CONVERT SQL functions), then the values may be corrupted when they are sent to the
database because they are not converted properly. If you have configured the
environment correctly and if the database character set supports the entire repertoire
of character data that may be input into the database, then you do not need to change
the current database character set. However, if your enterprise becomes more
globalized and you have additional characters or new languages to support, then you
may need to choose a character set with a greater character repertoire. Oracle
recommends that you use Unicode databases and datatypes.
ASCII Encoding
Table 2–2 shows how the ASCII character set is encoded. Row and column headings
denote hexadecimal digits. To find the encoded value of a character, read the column
number followed by the row number. For example, the code value of the character A is
0x41.
See Also:
■Chapter 6, "Supporting Multilingual Databases with Unicode"
■Oracle Database SQL Reference for more information about the
CHR and CONVERT SQL functions
■"Displaying a Code Chart with the Oracle Locale Builder" on
page 13-16
Table 2–2 7-Bit ASCII Character Set
-0 1 2 34567
0NUL DLE SP 0 @ P ' p
1SOH DC1 ! 1 A Q a q
2STX DC2 " 2 B R b r
3ETX DC3 # 3 C S c s
Character Set Encoding
Choosing a Character Set 2-5
As languages evolve to meet the needs of people around the world, new character sets
are created to support the languages. Typically, these new character sets support a
group of related languages based on the same script. For example, the ISO 8859
character set series was created to support different European languages. Table 2–3
shows the languages that are supported by the ISO 8859 character sets.
4EOT DC4 $ 4 D T d t
5ENQ NAK % 5 E U e u
6ACK SYN & 6 F V f v
7BEL ETB ' 7 G W g w
8BS CAN ( 8 H X h x
9TAB EM ) 9 I Y i y
ALF SUB * : J Z j z
BVT ESC + ; K [ k {
CFF FS , < L \ l |
DCR GS - = M ] m }
ESO RS . > N ^ n ~
FSI US / ? O _ o DEL
Table 2–2 (Cont.) 7-Bit ASCII Character Set
-0 1 2 34567
Character Set Encoding
2-6 Oracle Database Globalization Support Guide
Historically, character sets have provided restricted multilingual support, which has
been limited to groups of languages based on similar scripts. More recently, universal
character sets have emerged to enable greatly improved solutions for multilingual
support. Unicode is one such universal character set that encompasses most major
scripts of the modern world. As of version 5.0, Unicode supports more than 99,000
characters.
How are Characters Encoded?
Different types of encoding schemes have been created by the computer industry. The
character set you choose affects what kind of encoding scheme is used. This is
important because different encoding schemes have different performance
characteristics. These characteristics can influence your database schema and
application development. The character set you choose uses one of the following types
of encoding schemes:
■Single-Byte Encoding Schemes
■Multibyte Encoding Schemes
Table 2–3 lSO 8859 Character Sets
Standard Languages Supported
ISO 8859-1 Western European (Albanian, Basque, Breton, Catalan, Danish, Dutch, English, Faeroese,
Finnish, French, German, Greenlandic, Icelandic, Irish Gaelic, Italian, Latin, Luxemburgish,
Norwegian, Portuguese, Rhaeto-Romanic, Scottish Gaelic, Spanish, Swedish)
ISO 8859-2 Eastern European (Albanian, Croatian, Czech, English, German, Hungarian, Latin, Polish,
Romanian, Slovak, Slovenian, Serbian)
ISO 8859-3 Southeastern European (Afrikaans, Catalan, Dutch, English, Esperanto, German, Italian,
Maltese, Spanish, Turkish)
ISO 8859-4 Northern European (Danish, English, Estonian, Finnish, German, Greenlandic, Latin, Latvian,
Lithuanian, Norwegian, Sámi, Slovenian, Swedish)
ISO 8859-5 Eastern European (Cyrillic-based: Bulgarian, Byelorussian, Macedonian, Russian, Serbian,
Ukrainian)
ISO 8859-6 Arabic
ISO 8859-7 Greek
ISO 8859-8 Hebrew
ISO 8859-9 Western European (Albanian, Basque, Breton, Catalan, Cornish, Danish, Dutch, English,
Finnish, French, Frisian, Galician, German, Greenlandic, Irish Gaelic, Italian, Latin,
Luxemburgish, Norwegian, Portuguese, Rhaeto-Romanic, Scottish Gaelic, Spanish, Swedish,
Turkish)
ISO 8859-10 Northern European (Danish, English, Estonian, Faeroese, Finnish, German, Greenlandic,
Icelandic, Irish Gaelic, Latin, Lithuanian, Norwegian, Sámi, Slovenian, Swedish)
ISO 8859-13 Baltic Rim (English, Estonian, Finnish, Latin, Latvian, Norwegian)
ISO 8859-14 Celtic (Albanian, Basque, Breton, Catalan, Cornish, Danish, English, Galician, German,
Greenlandic, Irish Gaelic, Italian, Latin, Luxemburgish, Manx Gaelic, Norwegian, Portuguese,
Rhaeto-Romanic, Scottish Gaelic, Spanish, Swedish, Welsh)
ISO 8859-15 Western European (Albanian, Basque, Breton, Catalan, Danish, Dutch, English, Estonian,
Faroese, Finnish, French, Frisian, Galician, German, Greenlandic, Icelandic, Irish Gaelic, Italian,
Latin, Luxemburgish, Norwegian, Portuguese, Rhaeto-Romanic, Scottish Gaelic, Spanish,
Swedish)
See Also: Chapter 6, "Supporting Multilingual Databases with
Unicode"
Character Set Encoding
Choosing a Character Set 2-7
Single-Byte Encoding Schemes
Single-byte encoding schemes are efficient. They take up the least amount of space to
represent characters and are easy to process and program with because one character
can be represented in one byte. Single-byte encoding schemes are classified as one of
the following types:
■7-bit encoding schemes
Single-byte 7-bit encoding schemes can define up to 128 characters and normally
support just one language. One of the most common single-byte character sets,
used since the early days of computing, is ASCII (American Standard Code for
Information Interchange).
■8-bit encoding schemes
Single-byte 8-bit encoding schemes can define up to 256 characters and often
support a group of related languages. One example is ISO 8859-1, which supports
many Western European languages. Figure 2–1 shows the ISO 8859-1 8-bit
encoding scheme.
Figure 2–1 ISO 8859-1 8-Bit Encoding Scheme
Multibyte Encoding Schemes
Multibyte encoding schemes are needed to support ideographic scripts used in Asian
languages like Chinese or Japanese because these languages use thousands of
characters. These encoding schemes use either a fixed number or a variable number of
bytes to represent each character.
■Fixed-width multibyte encoding schemes
In a fixed-width multibyte encoding scheme, each character is represented by a
fixed number of bytes. The number of bytes is at least two in a multibyte encoding
scheme.
■Variable-width multibyte encoding schemes
A variable-width encoding scheme uses one or more bytes to represent a single
character. Some multibyte encoding schemes use certain bits to indicate the
number of bytes that represents a character. For example, if two bytes is the
maximum number of bytes used to represent a character, then the most significant
Length Semantics
2-8 Oracle Database Globalization Support Guide
bit can be used to indicate whether that byte is a single-byte character or the first
byte of a double-byte character.
■Shift-sensitive variable-width multibyte encoding schemes
Some variable-width encoding schemes use control codes to differentiate between
single-byte and multibyte characters with the same code values. A shift-out code
indicates that the following character is multibyte. A shift-in code indicates that
the following character is single-byte. Shift-sensitive encoding schemes are used
primarily on IBM platforms. Note that ISO-2022 character sets cannot be used as
database character sets, but they can be used for applications such as a mail server.
Naming Convention for Oracle Database Character Sets
Oracle Database uses the following naming convention for its character set names:
<region><number of bits used to represent a character><standard character set name>[S|C]
The parts of the names that appear between angle brackets are concatenated. The
optional S or C is used to differentiate character sets that can be used only on the
server (S) or only on the client (C).
Table 2–4 shows examples of Oracle Database character set names.
Length Semantics
In single-byte character sets, the number of bytes and the number of characters in a
string are the same. In multibyte character sets, a character or code point consists of
one or more bytes. Calculating the number of characters based on byte lengths can be
difficult in a variable-width character set. Calculating column lengths in bytes is called
byte semantics, while measuring column lengths in characters is called character
semantics.
Character semantics is useful for defining the storage requirements for multibyte
strings of varying widths. For example, in a Unicode database (AL32UTF8), suppose
Note: Keep in mind that:
■You should use the server character set (S) on the Macintosh
platform. The Macintosh client character sets are obsolete. On
EBCDIC platforms, use the server character set (S) on the
server and the client character set (C) on the client.
■UTF8 and UTFE are exceptions to the naming convention.
Table 2–4 Examples of Oracle Database Character Set Names
Oracle Database
Character Set
Name Description Region
Number of
Bits Used to
Represent a
Character
Standard
Character Set
Name
US7ASCII U.S. 7-bit ASCII US 7 ASCII
WE8ISO8859P1 Western European
8-bit ISO 8859 Part 1 WE (Western
Europe) 8 ISO8859 Part 1
JA16SJIS Japanese 16-bit
Shifted Japanese
Industrial Standard
JA 16 SJIS
Length Semantics
Choosing a Character Set 2-9
that you need to define a VARCHAR2 column that can store up to five Chinese
characters together with five English characters. Using byte semantics, this column
requires 15 bytes for the Chinese characters, which are three bytes long, and 5 bytes for
the English characters, which are one byte long, for a total of 20 bytes. Using character
semantics, the column requires 10 characters.
The following expressions use byte semantics:
■VARCHAR2(20 BYTE)
■SUBSTRB(string, 1, 20)
Note the BYTE qualifier in the VARCHAR2 expression and the B suffix in the SQL
function name.
The following expressions use character semantics:
■VARCHAR2(10 CHAR)
■SUBSTR(string, 1, 10)
Note the CHAR qualifier in the VARCHAR2 expression.
The NLS_LENGTH_SEMANTICS initialization parameter determines whether a new
column of character datatype uses byte or character semantics. The default value of the
parameter is BYTE. The BYTE and CHAR qualifiers shown in the VARCHAR2 definitions
should be avoided when possible because they lead to mixed-semantics databases.
Instead, set NLS_LENGTH_SEMANTICS in the initialization parameter file and define
column datatypes to use the default semantics based on the value of NLS_LENGTH_
SEMANTICS.
Byte semantics is the default for the database character set. Character length semantics
is the default and the only allowable kind of length semantics for NCHAR datatypes.
The user cannot specify the CHAR or BYTE qualifier for NCHAR definitions.
Consider the following example:
CREATE TABLE employees
( employee_id NUMBER(4)
, last_name NVARCHAR2(10)
, job_id NVARCHAR2(9)
, manager_id NUMBER(4)
, hire_date DATE
, salary NUMBER(7,2)
, department_id NUMBER(2)
) ;
When the NCHAR character set is AL16UTF16, last_name can hold up to 10 Unicode
code points. When the NCHAR character set is AL16UTF16, last_name can hold up to
20 bytes.
Figure 2–2 shows the number of bytes needed to store different kinds of characters in
the UTF-8 character set. The ASCII characters requires one byte, the Latin and Greek
characters require two bytes, the Asian character requires three bytes, and the
supplementary character requires four bytes of storage.
Choosing an Oracle Database Character Set
2-10 Oracle Database Globalization Support Guide
Figure 2–2 Bytes of Storage for Different Kinds of Characters
Choosing an Oracle Database Character Set
Oracle Database uses the database character set for:
■Data stored in SQL CHAR datatypes (CHAR, VARCHAR2, CLOB, and LONG)
■Identifiers such as table names, column names, and PL/SQL variables
■Entering and storing SQL and PL/SQL source code
The character encoding scheme used by the database is defined as part of the CREATE
DATABASE statement. All SQL CHAR datatype columns (CHAR, CLOB, VARCHAR2, and
LONG), including columns in the data dictionary, have their data stored in the
database character set. In addition, the choice of database character set determines
which characters can name objects in the database. SQL NCHAR datatype columns
(NCHAR, NCLOB, and NVARCHAR2) use the national character set.
After the database is created, you cannot change the character sets, with some
exceptions, without re-creating the database.
Consider the following questions when you choose an Oracle Database character set
for the database:
■What languages does the database need to support now?
■What languages does the database need to support in the future?
See Also:
■"SQL Functions for Different Length Semantics" on page 9-5 for
more information about the SUBSTR and SUBSTRB functions
■"Length Semantics" on page 3-31 for more information about
the NLS_LENGTH_SEMANTICS initialization parameter
■Chapter 6, "Supporting Multilingual Databases with Unicode"
for more information about Unicode and the NCHAR datatype
■Oracle Database SQL Reference for more information about the
SUBSTRB and SUBSTR functions and the BYTE and CHAR
qualifiers for character datatypes
Greek
Asian
ASCII
ASCII
Latin
ASCII
Latin
Supplementary character
Characters
Byte Storage
for UTF-8
63 C3 91 74 E4 BA 9C F0 9D 84 9E 64 C3 B6 D0 A4
1
byte
2
bytes
1
byte
3
bytes
4
bytes
1
byte
2
bytes
2
bytes
Choosing an Oracle Database Character Set
Choosing a Character Set 2-11
■Is the character set available on the operating system?
■What character sets are used on clients?
■How well does the application handle the character set?
■What are the performance implications of the character set?
■What are the restrictions associated with the character set?
The Oracle Database character sets are listed in "Character Sets" on page A-5. They are
named according to the languages and regions in which they are used. Some character
sets that are named for a region are also listed explicitly by language.
If you want to see the characters that are included in a character set, then:
■Check national, international, or vendor product documentation or standards
documents
■Use Oracle Locale Builder
This section contains the following topics:
■Current and Future Language Requirements
■Client Operating System and Application Compatibility
■Character Set Conversion Between Clients and the Server
■Performance Implications of Choosing a Database Character Set
■Restrictions on Database Character Sets
■Choosing a National Character Set
■Summary of Supported Datatypes
Current and Future Language Requirements
Several character sets may meet your current language requirements. Consider future
language requirements when you choose a database character set. If you expect to
support additional languages in the future, then choose a character set that supports
those languages to prevent the need to migrate to a different character set later.
Client Operating System and Application Compatibility
The database character set is independent of the operating system because Oracle
Database has its own globalization architecture. For example, on an English Windows
operating system, you can create and run a database with a Japanese character set.
However, when an application in the client operating system accesses the database, the
client operating system must be able to support the database character set with
appropriate fonts and input methods. For example, you cannot insert or retrieve
Japanese data on the English Windows operating system without first installing a
See Also:
■"UCS-2 Encoding" on page 6-3
■"Choosing a National Character Set" on page 2-14
■"Changing the Character Set After Database Creation" on
page 2-15
■Appendix A, "Locale Data"
■Chapter 13, "Customizing Locale Data"
Choosing an Oracle Database Character Set
2-12 Oracle Database Globalization Support Guide
Japanese font and input method. Another way to insert and retrieve Japanese data is to
use a Japanese operating system remotely to access the database server.
Character Set Conversion Between Clients and the Server
If you choose a database character set that is different from the character set on the
client operating system, then the Oracle Database can convert the operating system
character set to the database character set. Character set conversion has the following
disadvantages:
■Potential data loss
■Increased overhead
Character set conversions can sometimes cause data loss. For example, if you are
converting from character set A to character set B, then the destination character set B
must have the same character set repertoire as A. Any characters that are not available
in character set B are converted to a replacement character. The replacement character
is often specified as a question mark or as a linguistically related character. For
example, ä (a with an umlaut) may be converted to a. If you have distributed
environments, then consider using character sets with similar character repertoires to
avoid loss of data.
Character set conversion may require copying strings between buffers several times
before the data reaches the client. The database character set should always be a
superset or equivalent of the native character set of the client's operating system. The
character sets used by client applications that access the database usually determine
which superset is the best choice.
If all client applications use the same character set, then that character set is usually the
best choice for the database character set. When client applications use different
character sets, the database character set should be a superset of all the client character
sets. This ensures that every character is represented when converting from a client
character set to the database character set.
Performance Implications of Choosing a Database Character Set
For best performance, choose a character set that avoids character set conversion and
uses the most efficient encoding for the languages desired. Single-byte character sets
result in better performance than multibyte character sets, and they also are the most
efficient in terms of space requirements. However, single-byte character sets limit how
many languages you can support.
Restrictions on Database Character Sets
ASCII-based character sets are supported only on ASCII-based platforms. Similarly,
you can use an EBCDIC-based character set only on EBCDIC-based platforms.
The database character set is used to identify SQL and PL/SQL source code. In order
to do this, it must have either EBCDIC or 7-bit ASCII as a subset, whichever is native
to the platform. Therefore, it is not possible to use a fixed-width, multibyte character
set as the database character set. Currently, only the AL16UTF16 character set cannot
be used as a database character set.
Restrictions on Character Sets Used to Express Names
Table 2–5 lists the restrictions on the character sets that can be used to express names.
See Also: Chapter 11, "Character Set Migration"
Choosing an Oracle Database Character Set
Choosing a Character Set 2-13
For a list of supported string formats and character sets, including LOB data (LOB,
BLOB, CLOB, and NCLOB), see Table 2–7 on page 2-14.
Database Character Set Statement of Direction
A list of character sets has been compiled in Table A–4, " Recommended ASCII
Database Character Sets" and Table A–5, " Recommended EBCDIC Database Character
Sets" that Oracle strongly recommends for usage as the database character set. Other
Oracle-supported character sets that do not appear on this list can continue to be used
in Oracle Database 11g Release 1, but may be desupported in a future release. Starting
with the next major functional release after Oracle Database 10g Release 2, the choice
for the database character set will be limited to this list of recommended character sets
for new system deployment. Customers will still be able to migrate their existing
databases in the next major functional release after Oracle Database 10g Release 2 even
if the character set is not on the recommended list. However, Oracle suggests that
customers migrate to a recommended character set as soon as possible. At the top of
the list of character sets that Oracle recommends for all new system deployment, is the
Unicode character set AL32UTF8.
Choosing Unicode as a Database Character Set
Oracle recommends using Unicode for all new system deployments. Migrating legacy
systems to Unicode is also recommended. Deploying your systems today in Unicode
offers many advantages in usability, compatibility, and extensibility. Oracle Database
enables you to deploy high-performing systems faster and more easily while utilizing
the advantages of Unicode. Even if you do not need to support multilingual data
today, nor have any requirement for Unicode, it is still likely to be the best choice for a
new system in the long run and will ultimately save you time and money as well as
Table 2–5 Restrictions on Character Sets Used to Express Names
Name Single-Byte
Variable
Width Comments
Column names Yes Yes -
Schema objects Yes Yes -
Comments Yes Yes -
Database link names Yes No -
Database names Yes No -
File names (datafile, log file, control
file, initialization parameter file) Yes No -
Instance names Yes No -
Directory names Yes No -
Keywords Yes No Can be expressed in English ASCII or EBCDIC
characters only
Recovery Manager file names Yes No -
Rollback segment names Yes No The ROLLBACK_SEGMENTS parameter does not
support NLS
Stored script names Yes Yes -
Tablespace names Yes No -
Choosing an Oracle Database Character Set
2-14 Oracle Database Globalization Support Guide
give you competitive advantages in the long term. See Chapter 6, "Supporting
Multilingual Databases with Unicode" for more information about Unicode.
Choosing a National Character Set
The term national character set refers to an alternative character set that enables you
to store Unicode character data in a database that does not have a Unicode database
character set. Other reasons for choosing a national character set are:
■The properties of a different character encoding scheme may be more desirable for
extensive character processing operations.
■Programming in the national character set is easier.
SQL NCHAR, NVARCHAR2, and NCLOB datatypes support Unicode data only. You can
use either the UTF8 or the AL16UTF16 character set. The default is AL16UTF16.
Summary of Supported Datatypes
Table 2–6 lists the datatypes that are supported for different encoding schemes.
Table 2–7 lists the SQL datatypes that are supported for abstract datatypes.
You can create an abstract datatype with the NCHAR attribute as follows:
SQL> CREATE TYPE tp1 AS OBJECT (a NCHAR(10));
Type created.
SQL> CREATE TABLE t1 (a tp1);
Table created.
See Also: Chapter 6, "Supporting Multilingual Databases with
Unicode"
Table 2–6 SQL Datatypes Supported for Encoding Schemes
Datatype Single Byte Multibyte Non-Unicode Multibyte Unicode
CHAR Yes Yes Yes
VARCHAR2 Yes Yes Yes
NCHAR No No Yes
NVARCHAR2 No No Yes
BLOB Yes Yes Yes
CLOB Yes Yes Yes
LONG Yes Yes Yes
NCLOB No No Yes
Note: BLOBs process characters as a series of byte sequences.
The data is not subject to any NLS-sensitive operations.
Table 2–7 Abstract Datatype Support for SQL Datatypes
Abstract Datatype CHAR NCHAR BLOB CLOB NCLOB
Object Yes Yes Yes Yes Yes
Collection Yes Yes Yes Yes Yes
Monolingual Database Scenario
Choosing a Character Set 2-15
Changing the Character Set After Database Creation
You may wish to change the database character set after the database has been created.
For example, you may find that the number of languages that need to be supported in
your database has increased. In most cases, you need to do a full export/import to
properly convert all data to the new character set. However, if, and only if, the new
character set is a strict superset of all of the schema data, then it is possible to use the
CSALTER script to expedite the change in the database character set.
Monolingual Database Scenario
The simplest example of a database configuration is a client and a server that run in
the same language environment and use the same character set. This monolingual
scenario has the advantage of fast response because the overhead associated with
character set conversion is avoided. Figure 2–3 shows a database server and a client
that use the same character set. The Japanese client and the server both use the
JA16EUC character set.
Figure 2–3 Monolingual Database Scenario
You can also use a multitier architecture. Figure 2–4 shows an application server
between the database server and the client. The application server and the database
server use the same character set in a monolingual scenario. The server, the application
server, and the client use the JA16EUC character set.
See Also: Oracle Database Application Developer's Guide -
Object-Relational Features for more information about objects and
collections
See Also:
■Chapter 11, "Character Set Migration"
■Oracle Database Upgrade Guide for more information about
exporting and importing data
■Oracle Streams Concepts and Administration for information
about using Streams to change the character set of a database
while the database remains online
Unix
(JA16EUC)
Japanese
Server
(JA16EUC)
Monolingual Database Scenario
2-16 Oracle Database Globalization Support Guide
Figure 2–4 Multitier Monolingual Database Scenario
Character Set Conversion in a Monolingual Scenario
Character set conversion may be required in a client/server environment if a client
application resides on a different platform than the server and if the platforms do not
use the same character encoding schemes. Character data passed between client and
server must be converted between the two encoding schemes. Character conversion
occurs automatically and transparently through Oracle Net.
You can convert between any two character sets. Figure 2–5 shows a server and one
client with the JA16EUC Japanese character set. The other client uses the JA16SJIS
Japanese character set.
Figure 2–5 Character Set Conversion
When a target character set does not contain all of the characters in the source data,
replacement characters are used. If, for example, a server uses US7ASCII and a
German client uses WE8ISO8859P1, then the German character ß is replaced with ?
and ä is replaced with a.
Replacement characters may be defined for specific characters as part of a character set
definition. When a specific replacement character is not defined, a default replacement
character is used. To avoid the use of replacement characters when converting from a
client character set to a database character set, the server character set should be a
superset of all the client character sets.
Figure 2–6 shows that data loss occurs when the database character set does not
include all of the characters in the client character set. The database character set is
US7ASCII. The client's character set is WE8MSWIN1252, and the language used by the
client is German. When the client inserts a string that contains ß, the database replaces
ß with ?, resulting in lost data.
Browser
Japanese
Server
(JA16EUC)
Application
Server
(JA16EUC)
Unix
(JA16EUC)
Windows
(JA16SJIS)
Character
Conversion
Japanese
Server
(JA16EUC)
Multilingual Database Scenarios
Choosing a Character Set 2-17
Figure 2–6 Data Loss During Character Conversion
If German data is expected to be stored on the server, then a database character set that
supports German characters should be used for both the server and the client to avoid
data loss and conversion overhead.
When one of the character sets is a variable-width multibyte character set, conversion
can introduce noticeable overhead. Carefully evaluate your situation and choose
character sets to avoid conversion as much as possible.
Multilingual Database Scenarios
Multilingual support can be restricted or unrestricted. This section contains the
following topics:
■Restricted Multilingual Support
■Unrestricted Multilingual Support
Restricted Multilingual Support
Some character sets support multiple languages because they have related writing
systems or scripts. For example, the Oracle Database WE8ISO8859P1 character set
supports the following Western European languages:
Catalan
Danish
Dutch
English
Finnish
French
German
Icelandic
Italian
Norwegian
Portuguese
Spanish
German
Windows
(WE8MSWIN1252)
Character
Conversion
American
Database
Server
(US7ASCII)
?
Multilingual Database Scenarios
2-18 Oracle Database Globalization Support Guide
Swedish
These languages all use a Latin-based writing script.
When you use a character set that supports a group of languages, your database has
restricted multilingual support.
Figure 2–7 shows a Western European server that used the WE8ISO8850P1 Oracle
Database character set, a French client that uses the same character set as the server,
and a German client that uses the WE8DEC character set. The German client requires
character conversion because it is using a different character set than the server.
Figure 2–7 Restricted Multilingual Support
Unrestricted Multilingual Support
If you need unrestricted multilingual support, then use a universal character set such
as Unicode for the server database character set. Unicode has two major encoding
schemes:
■UTF-16: Each character is either 2 or 4 bytes long.
■UTF-8: Each character takes 1 to 4 bytes to store.
Oracle Database provides support for UTF-8 as a database character set and both
UTF-8 and UTF-16 as national character sets.
Character set conversion between a UTF-8 database and any single-byte character set
introduces very little overhead.
Conversion between UTF-8 and any multibyte character set has some overhead. There
is no data loss from conversion, with the following exceptions:
■Some multibyte character sets do not support user-defined characters during
character set conversion to and from UTF-8.
■Some Unicode characters are mapped to more than one character in another
character set. For example, one Unicode character is mapped to three characters in
the JA16SJIS character set. This means that a round-trip conversion may not result
in the original JA16SJIS character.
German
(WE8DEC)
French
(WE8ISO8859P1)
Western
European
Server
Character
Conversion
(WE8ISO8859P1)
Multilingual Database Scenarios
Choosing a Character Set 2-19
Figure 2–8 shows a server that uses the AL32UTF8 Oracle Database character set that
is based on the Unicode UTF-8 character set.
Figure 2–8 Unrestricted Multilingual Support Scenario in a Client/Server Configuration
There are four clients:
■A French client that uses the WE8ISO8859P1 Oracle Database character set
■A German client that uses the WE8DEC character set
■A Japanese client that uses the JA16EUC character set
■A Japanese client that used the JA16SJIS character set
Character conversion takes place between each client and the server, but there is no
data loss because AL32UTF8 is a universal character set. If the German client tries to
retrieve data from one of the Japanese clients, then all of the Japanese characters in the
data are lost during the character set conversion.
Figure 2–9 shows a Unicode solution for a multitier configuration.
Japanese
Client
(JA16SJIS)
German
Client
(WE8DEC)
French
Client
(WE8ISO8859P1)
Japanese
Client
(JA16EUC)
Character
Conversion
Character
Conversion
Character
Conversion
Character
Conversion
Unicode
Database
(AL32UTF8)
Multilingual Database Scenarios
2-20 Oracle Database Globalization Support Guide
Figure 2–9 Multitier Unrestricted Multilingual Support Scenario in a Multitier
Configuration
The database, the application server, and each client use the AL32UTF8 character set.
This eliminates the need for character conversion even though the clients are French,
German, and Japanese.
See Also: Chapter 6, "Supporting Multilingual Databases with
Unicode"
Browser
German
Client
Browser
Japanese
Client
Browser
French
Client
Unicode
Database
(AL32UTF8)
Application
Server
(UTF-8)
(UTF-8)
(UTF-8)
(UTF-8)
Setting Up a Globalization Support Environment 3-1
3
Setting Up a Globalization Support
Environment
This chapter tells how to set up a globalization support environment. It includes the
following topics:
■Setting NLS Parameters
■Choosing a Locale with the NLS_LANG Environment Variable
■NLS Database Parameters
■Language and Territory Parameters
■Date and Time Parameters
■Calendar Definitions
■Numeric and List Parameters
■Monetary Parameters
■Linguistic Sort Parameters
■Character Set Conversion Parameter
■Length Semantics
Setting NLS Parameters
NLS (National Language Support) parameters determine the locale-specific behavior
on both the client and the server. NLS parameters can be specified in the following
ways:
■As initialization parameters on the server
You can include parameters in the initialization parameter file to specify a default
session NLS environment. These settings have no effect on the client side; they
control only the server's behavior. For example:
NLS_TERRITORY = "CZECH REPUBLIC"
■As environment variables on the client
You can use NLS environment variables, which may be platform-dependent, to
specify locale-dependent behavior for the client and also to override the default
values set for the session in the initialization parameter file. For example, on a
UNIX system:
% setenv NLS_SORT FRENCH
Setting NLS Parameters
3-2 Oracle Database Globalization Support Guide
■With the ALTER SESSION statement
You can use NLS parameters that are set in an ALTER SESSION statement to
override the default values that are set for the session in the initialization
parameter file or set by the client with environment variables.
ALTER SESSION SET NLS_SORT = FRENCH;
■In SQL functions
You can use NLS parameters explicitly to hardcode NLS behavior within a SQL
function. This practice overrides the default values that are set for the session in
the initialization parameter file, set for the client with environment variables, or
set for the session by the ALTER SESSION statement. For example:
TO_CHAR(hiredate, 'DD/MON/YYYY', 'nls_date_language = FRENCH')
Table 3–1 shows the precedence order of the different methods of setting NLS
parameters. Higher priority settings override lower priority settings. For example, a
default value has the lowest priority and can be overridden by any other method.
Table 3–2 lists the available NLS parameters. Because the SQL function NLS
parameters can be specified only with specific functions, the table does not show the
SQL function scope.
See Also: Oracle Database SQL Reference for more information
about the ALTER SESSION statement
See Also: Oracle Database SQL Reference for more information
about SQL functions, including the TO_CHAR function
Table 3–1 Methods of Setting NLS Parameters and Their Priorities
Priority Method
1 (highest) Explicitly set in SQL functions
2 Set by an ALTER SESSION statement
3 Set as an environment variable
4 Specified in the initialization parameter file
5Default
Table 3–2 NLS Parameters
Parameter Description Default
Scope:
I = Initialization Parameter File
E = Environment Variable
A = ALTER SESSION
NLS_CALENDAR Calendar system Gregorian I, E, A
NLS_COMP SQL, PL/SQL operator
comparison BINARY I, E, A
NLS_CREDIT Credit accounting symbol Derived from
NLS_TERRITORY
E
NLS_CURRENCY Local currency symbol Derived from
NLS_TERRITORY
I, E, A
NLS_DATE_FORMAT Date format Derived from
NLS_TERRITORY
I, E, A
Choosing a Locale with the NLS_LANG Environment Variable
Setting Up a Globalization Support Environment 3-3
Choosing a Locale with the NLS_LANG Environment Variable
A locale is a linguistic and cultural environment in which a system or program is
running. Setting the NLS_LANG environment parameter is the simplest way to specify
locale behavior for Oracle Database software. It sets the language and territory used by
the client application and the database server. It also sets 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. NLS_LANG is set in
the registry on Windows platforms.
NLS_DATE_LANGUAGE Language for day and month
names Derived from
NLS_LANGUAGE
I, E, A
NLS_DEBIT Debit accounting symbol Derived from
NLS_TERRITORY
E
NLS_ISO_CURRENCY ISO international currency
symbol Derived from
NLS_TERRITORY
I, E, A
NLS_LANG
See Also: "Choosing a
Locale with the NLS_LANG
Environment Variable" on
page 3-3
Language, territory, character
set AMERICAN_
AMERICA.
US7ASCII
E
NLS_LANGUAGE Language Derived from
NLS_LANG
I, A
NLS_LENGTH_
SEMANTICS How strings are treated BYTE I, E, A
NLS_LIST_SEPARATOR Character that separates items
in a list Derived from
NLS_TERRITORY
E
NLS_MONETARY_
CHARACTERS Monetary symbol for dollar
and cents (or their
equivalents)
Derived from
NLS_TERRITORY
E
NLS_NCHAR_CONV_
EXCP Reports data loss during a
character type conversion FALSE I, A
NLS_NUMERIC_
CHARACTERS Decimal character and group
separator Derived from
NLS_TERRITORY
I, E, A
NLS_SORT Character sort sequence Derived from
NLS_LANGUAGE
I, E, A
NLS_TERRITORY Territory Derived from
NLS_LANG
I, A
NLS_TIMESTAMP_
FORMAT Timestamp Derived from
NLS_TERRITORY
I, E, A
NLS_TIMESTAMP_TZ_
FORMAT Timestamp with time zone Derived from
NLS_TERRITORY
I, E, A
NLS_DUAL_CURRENCY Dual currency symbol Derived from
NLS_TERRITORY
I, E, A
Table 3–2 (Cont.) NLS Parameters
Parameter Description Default
Scope:
I = Initialization Parameter File
E = Environment Variable
A = ALTER SESSION
Choosing a Locale with the NLS_LANG Environment Variable
3-4 Oracle Database Globalization Support Guide
The NLS_LANG parameter has three components: language, territory, and character set.
Specify it in the following format, including the punctuation:
NLS_LANG = language_territory.charset
For example, if the Oracle Universal Installer does not populate NLS_LANG, then its
value by default is AMERICAN_AMERICA.US7ASCII. The language is AMERICAN, the
territory is AMERICA, and the character set is US7ASCII. The values in NLS_LANG and
other NLS parameters are case-insensitive.
Each component of the NLS_LANG parameter controls the operation of a subset of
globalization support features:
■language
Specifies conventions such as the language used for Oracle Database messages,
sorting, day names, and month names. Each supported language has a unique
name; for example, AMERICAN, FRENCH, or GERMAN. The language argument
specifies default values for the territory and character set arguments. If the
language is not specified, then the value defaults to AMERICAN.
■territory
Specifies conventions such as the default date, monetary, and numeric formats.
Each supported territory has a unique name; for example, AMERICA, FRANCE, or
CANADA. If the territory is not specified, then the value is derived from the
language value.
■charset
Specifies the character set used by the client application (normally the Oracle
Database character set that corresponds to the user's terminal character set or the
OS character set). Each supported character set has a unique acronym, for
example, US7ASCII, WE8ISO8859P1, WE8DEC, WE8MSWIN1252, or JA16EUC.
Each language has a default character set associated with it.
The three components of NLS_LANG can be specified in many combinations, as in the
following examples:
NLS_LANG = AMERICAN_AMERICA.WE8MSWIN1252
NLS_LANG = FRENCH_CANADA.WE8ISO8859P1
NLS_LANG = JAPANESE_JAPAN.JA16EUC
Note that illogical combinations can be set but do not work properly. For example, the
following specification tries to support Japanese by using a Western European
character set:
NLS_LANG = JAPANESE_JAPAN.WE8ISO8859P1
Note: All components of the NLS_LANG definition are optional;
any item that is not specified uses its default value. If you specify
territory or character set, then you must include the preceding
delimiter [underscore (_) for territory, period (.) for character set].
Otherwise, the value is parsed as a language name.
For example, to set only the territory portion of NLS_LANG, use the
following format: NLS_LANG=_JAPAN
Choosing a Locale with the NLS_LANG Environment Variable
Setting Up a Globalization Support Environment 3-5
Because the WE8ISO8859P1 character set does not support any Japanese characters,
you cannot store or display Japanese data if you use this definition for NLS_LANG.
The rest of this section includes the following topics:
■Specifying the Value of NLS_LANG
■Overriding Language and Territory Specifications
■Locale Variants
Specifying the Value of NLS_LANG
In a UNIX operating system C-shell session, you can specify the value of NLS_LANG by
entering a statement similar to the following example:
% setenv NLS_LANG FRENCH_FRANCE.WE8ISO8859P1
Because NLS_LANG is an environment variable, it is read by the client application at
startup time. The client communicates the information defined by NLS_LANG to the
server when it connects to the database server.
The following examples show how date and number formats are affected by the NLS_
LANG parameter.
Example 3–1 Setting NLS_LANG to American_America.WE8ISO8859P1
Set NLS_LANG so that the language is AMERICAN, the territory is AMERICA, and the
Oracle Database character set is WE8ISO8859P1:
% setenv NLS_LANG American_America.WE8ISO8859P1
Enter a SELECT statement:
SQL> SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees;
You should see results similar to the following output:
LAST_NAME HIRE_DATE SALARY
------------------------- --------- ----------
Sciarra 30-SEP-97 962.5
Urman 07-MAR-98 975
Popp 07-DEC-99 862.5
Example 3–2 Setting NLS_LANG to French_France.WE8ISO8859P1
Set NLS_LANG so that the language is FRENCH, the territory is FRANCE, and the Oracle
Database character set is WE8ISO8859P1:
% setenv NLS_LANG French_France.WE8ISO8859P1
Then the query shown in Example 3–1 returns the following output:
LAST_NAME HIRE_DAT SALARY
------------------------- -------- ----------
See Also:
■Appendix A, "Locale Data" for a complete list of supported
languages, territories, and character sets
■Your operating system documentation for information about
additional globalization settings that may be necessary for your
platform
Choosing a Locale with the NLS_LANG Environment Variable
3-6 Oracle Database Globalization Support Guide
Sciarra 30/09/97 962,5
Urman 07/03/98 975
Popp 07/12/99 862,5
Note that the date format and the number format have changed. The numbers have
not changed, because the underlying data is the same.
Overriding Language and Territory Specifications
The NLS_LANG parameter sets the language and territory environment used by both
the server session (for example, SQL command execution) and the client application
(for example, display formatting in Oracle Database tools). Using this parameter
ensures that the language environments of both the database and the client application
are automatically the same.
The language and territory components of the NLS_LANG parameter determine the
default values for other detailed NLS parameters, such as date format, numeric
characters, and linguistic sorting. Each of these detailed parameters can be set in the
client environment to override the default values if the NLS_LANG parameter has
already been set.
If the NLS_LANG parameter is not set, then the server session environment remains
initialized with values of NLS_LANGUAGE, NLS_TERRITORY, and other NLS instance
parameters from the initialization parameter file. You can modify these parameters
and restart the instance to change the defaults.
You might want to modify the NLS environment dynamically during the session. To
do so, you can use the ALTER SESSION statement to change NLS_LANGUAGE, NLS_
TERRITORY, and other NLS parameters.
The ALTER SESSION statement modifies only the session environment. The local
client NLS environment is not modified, unless the client explicitly retrieves the new
settings and modifies its local environment.
Locale Variants
Before Oracle Database 10g, Oracle defined language and territory definitions
separately. This resulted in the definition of a territory being independent of the
language setting of the user. In Oracle Database 10g, some territories can have different
date, time, number, and monetary formats based on the language setting of a user.
This type of language-dependent territory definition is called a locale variant.
For the variant to work properly, both NLS_TERRITORY and NLS_LANGUAGE must be
specified.
Table 3–3 shows the territories that have been enhanced to support variations.
Note: You cannot modify the setting for the client character set
with the ALTER SESSION statement.
See Also:
■"Overriding Default Values for NLS_LANGUAGE and NLS_
TERRITORY During a Session" on page 3-13
■Oracle Database SQL Reference
Choosing a Locale with the NLS_LANG Environment Variable
Setting Up a Globalization Support Environment 3-7
Should the NLS_LANG Setting Match the Database Character Set?
The NLS_LANG character set should reflect the setting of the operating system
character set of the client. For example, if the database character set is AL32UTF8 and
the client is running on a Windows operating system, then you should not set
AL32UTF8 as the client character set in the NLS_LANG parameter because there are no
Table 3–3 Oracle Database Locale Variants
Oracle Database Territory Oracle Database Language
BELGIUM DUTCH
BELGIUM FRENCH
BELGIUM GERMAN
CANADA FRENCH
CANADA ENGLISH
DJIBOUTI FRENCH
DJIBOUTI ARABIC
FINLAND FINLAND
FINLAND SWEDISH
HONG KONG TRADITIONAL CHINESE
HONG KONG ENGLISH
INDIA ENGLISH
INDIA ASSAMESE
INDIA BANGLA
INDIA GUJARATI
INDIA HINDI
INDIA KANNADA
INDIA MALAYALAM
INDIA MARATHI
INDIA ORIYA
INDIA PUNJABI
INDIA TAMIL
INDIA TELUGU
LUXEMBOURG GERMAN
LUXEMBOURG FRENCH
SINGAPORE ENGLISH
SINGAPORE MALAY
SINGAPORE SIMPLIFIED CHINESE
SINGAPORE TAMIL
SWITZERLAND GERMAN
SWITZERLAND FRENCH
SWITZERLAND ITALIAN
NLS Database Parameters
3-8 Oracle Database Globalization Support Guide
UTF-8 WIN32 clients. Instead, the NLS_LANG setting should reflect the code page of
the client. For example, on an English Windows client, the code page is 1252. An
appropriate setting for NLS_LANG is AMERICAN_AMERICA.WE8MSWIN1252.
Setting NLS_LANG correctly enables proper conversion from the client operating
system character set to the database character set. When these settings are the same,
Oracle Database assumes that the data being sent or received is encoded in the same
character set as the database character set, so character set validation or conversion
may not be performed. This can lead to corrupt data if the client code page and the
database character set are different and conversions are necessary.
NLS Database Parameters
When a new database is created during the execution of the CREATE DATABASE
statement, the NLS-related database configuration is established. The current NLS
instance parameters are stored in the data dictionary along with the database and
national character sets. The NLS instance parameters are read from the initialization
parameter file at instance startup.
You can find the values for NLS parameters by using:
■NLS Data Dictionary Views
■NLS Dynamic Performance Views
■OCINlsGetInfo() Function
NLS Data Dictionary Views
Applications can check the session, instance, and database NLS parameters by
querying the following data dictionary views:
■NLS_SESSION_PARAMETERS shows the NLS parameters and their values for the
session that is querying the view. It does not show information about the character
set.
■NLS_INSTANCE_PARAMETERS shows the current NLS instance parameters that
have been explicitly set and the values of the NLS instance parameters.
■NLS_DATABASE_PARAMETERS shows the values of the NLS parameters for the
database. The values are stored in the database.
NLS Dynamic Performance Views
Applications can check the following NLS dynamic performance views:
■V$NLS_VALID_VALUES lists values for the following NLS parameters: NLS_
LANGUAGE, NLS_SORT, NLS_TERRITORY, NLS_CHARACTERSET
■V$NLS_PARAMETERS shows current values of the following NLS parameters:
NLS_CALENDAR, NLS_CHARACTERSET, NLS_CURRENCY, NLS_DATE_FORMAT,
NLS_DATE_LANGUAGE, NLS_ISO_CURRENCY, NLS_LANGUAGE, NLS_NUMERIC_
CHARACTERS, NLS_SORT, NLS_TERRITORY, NLS_NCHAR_CHARACTERSET, NLS_
COMP, NLS_LENGTH_SEMANTICS, NLS_NCHAR_CONV_EXP, NLS_TIMESTAMP_
FORMAT, NLS_TIMESTAMP_TZ_FORMAT, NLS_TIME_FORMAT, NLS_TIME_TZ_
FORMAT
See Also: Oracle Database Installation Guide for 32-Bit Windows for
more information about commonly used values of the NLS_LANG
parameter in Windows
Language and Territory Parameters
Setting Up a Globalization Support Environment 3-9
OCINlsGetInfo() Function
User applications can query client NLS settings with the OCINlsGetInfo() function.
Language and Territory Parameters
This section contains information about the following parameters:
■NLS_LANGUAGE
■NLS_TERRITORY
NLS_LANGUAGE
NLS_LANGUAGE specifies the default conventions for the following session
characteristics:
■Language for server messages
■Language for day and month names and their abbreviations (specified in the SQL
functions TO_CHAR and TO_DATE)
■Symbols for equivalents of AM, PM, AD, and BC. (A.M., P.M., A.D., and B.C. are
valid only if NLS_LANGUAGE is set to AMERICAN.)
■Default sorting sequence for character data when ORDER BY is specified. (GROUP
BY uses a binary sort unless ORDER BY is specified.)
■Writing direction
■Affirmative and negative response strings (for example, YES and NO)
The value specified for NLS_LANGUAGE in the initialization parameter file is the
default for all sessions in that instance. For example, to specify the default session
language as French, the parameter should be set as follows:
NLS_LANGUAGE = FRENCH
Consider the following server message:
ORA-00942: table or view does not exist
When the language is French, the server message appears as follows:
ORA-00942: table ou vue inexistante
Messages used by the server are stored in binary-format files that are placed in the
$ORACLE_HOME/product_name/mesg directory, or the equivalent for your
See Also: Oracle Database Reference
See Also: "Getting Locale Information in OCI" on page 10-2 for
the description of OCINlsGetInfo()
Property Description
Parameter type String
Parameter scope Initialization parameter and ALTER SESSION
Default value Derived from NLS_LANG
Range of values Any valid language name
Language and Territory Parameters
3-10 Oracle Database Globalization Support Guide
operating system. Multiple versions of these files can exist, one for each supported
language, using the following filename convention:
<product_id><language_abbrev>.MSB
For example, the file containing the server messages in French is called oraf.msb,
because ORA is the product ID (<product_id>) and F is the language abbreviation
(<language_abbrev>) for French. The product_name is rdbms, so it is in the
$ORACLE_HOME/rdbms/mesg directory.
If NLS_LANG is specified in the client environment, then the value of NLS_LANGUAGE
in the initialization parameter file is overridden at connection time.
Messages are stored in these files in one specific character set, depending on the
language and the operating system. If this character set is different from the database
character set, then message text is automatically converted to the database character
set. If necessary, it is then converted to the client character set if the client character set
is different from the database character set. Hence, messages are displayed correctly at
the user's terminal, subject to the limitations of character set conversion.
The language-specific binary message files that are actually installed depend on the
languages that the user specifies during product installation. Only the English binary
message file and the language-specific binary message files specified by the user are
installed.
The default value of NLS_LANGUAGE may be specific to the operating system. You can
alter the NLS_LANGUAGE parameter by changing its value in the initialization
parameter file and then restarting the instance.
All messages and text should be in the same language. For example, when you run an
Oracle Developer application, the messages and boilerplate text that you see originate
from three sources:
■Messages from the server
■Messages and boilerplate text generated by Oracle Forms
■Messages and boilerplate text generated by the application
NLS_LANGUAGE determines the language used for the first two kinds of text. The
application is responsible for the language used in its messages and boilerplate text.
The following examples show behavior that results from setting NLS_LANGUAGE to
different values.
Example 3–3 NLS_LANGUAGE=ITALIAN
Use the ALTER SESSION statement to set NLS_LANGUAGE to Italian:
ALTER SESSION SET NLS_LANGUAGE=Italian;
Enter a SELECT statement:
SQL> SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees;
You should see results similar to the following output:
LAST_NAME HIRE_DATE SALARY
------------------------- --------- ----------
See Also: Your operating system-specific Oracle Database
documentation for more information about the default value of
NLS_LANGUAGE
Language and Territory Parameters
Setting Up a Globalization Support Environment 3-11
Sciarra 30-SET-97 962.5
Urman 07-MAR-98 975
Popp 07-DIC-99 862.5
Note that the month name abbreviations are in Italian.
Example 3–4 NLS_LANGUAGE=GERMAN
Use the ALTER SESSION statement to change the language to German:
SQL> ALTER SESSION SET NLS_LANGUAGE=German;
Enter the same SELECT statement:
SQL> SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees;
You should see results similar to the following output:
LAST_NAME HIRE_DATE SALARY
------------------------- --------- ----------
Sciarra 30-SEP-97 962.5
Urman 07-MÄR-98 975
Popp 07-DEZ-99 862.5
Note that the language of the month abbreviations has changed.
NLS_TERRITORY
NLS_TERRITORY specifies the conventions for the following default date and numeric
formatting characteristics:
■Date format
■Decimal character and group separator
■Local currency symbol
■ISO currency symbol
■Dual currency symbol
■First day of the week
■Credit and debit symbols
■ISO week flag
■List separator
See Also: "Overriding Default Values for NLS_LANGUAGE and
NLS_TERRITORY During a Session" on page 3-13 for more
information about using the ALTER SESSION statement
Property Description
Parameter type String
Parameter scope Initialization parameter and ALTER SESSION
Default value Derived from NLS_LANG
Range of values Any valid territory name
Language and Territory Parameters
3-12 Oracle Database Globalization Support Guide
The value specified for NLS_TERRITORY in the initialization parameter file is the
default for the instance. For example, to specify the default as France, the parameter
should be set as follows:
NLS_TERRITORY = FRANCE
When the territory is FRANCE, numbers are formatted using a comma as the decimal
character.
You can alter the NLS_TERRITORY parameter by changing the value in the
initialization parameter file and then restarting the instance. The default value of NLS_
TERRITORY can be specific to the operating system.
If NLS_LANG is specified in the client environment, then the value of NLS_TERRITORY
in the initialization parameter file is overridden at connection time.
The territory can be modified dynamically during the session by specifying the new
NLS_TERRITORY value in an ALTER SESSION statement. Modifying NLS_
TERRITORY resets all derived NLS session parameters to default values for the new
territory.
To change the territory to France during a session, issue the following ALTER
SESSION statement:
ALTER SESSION SET NLS_TERRITORY = France;
The following examples show behavior that results from different settings of NLS_
TERRITORY and NLS_LANGUAGE.
Example 3–5 NLS_LANGUAGE=AMERICAN, NLS_TERRITORY=AMERICA
Enter the following SELECT statement:
SQL> SELECT TO_CHAR(salary,'L99G999D99') salary FROM employees;
When NLS_TERRITORY is set to AMERICA and NLS_LANGUAGE is set to AMERICAN,
results similar to the following should appear:
SALARY
--------------------
$24,000.00
$17,000.00
$17,000.00
Example 3–6 NLS_LANGUAGE=AMERICAN, NLS_TERRITORY=GERMANY
Use an ALTER SESSION statement to change the territory to Germany:
ALTER SESSION SET NLS_TERRITORY = Germany;
Session altered.
Enter the same SELECT statement as before:
SQL> SELECT TO_CHAR(salary,'L99G999D99') salary FROM employees;
You should see results similar to the following output:
SALARY
--------------------
€24.000,00
€17.000,00
€17.000,00
Language and Territory Parameters
Setting Up a Globalization Support Environment 3-13
Note that the currency symbol has changed from $ to €. The numbers have not
changed because the underlying data is the same.
Example 3–7 NLS_LANGUAGE=GERMAN, NLS_TERRITORY=GERMANY
Use an ALTER SESSION statement to change the language to German:
ALTER SESSION SET NLS_LANGUAGE = German;
Sitzung wurde geändert.
Note that the server message now appears in German.
Enter the same SELECT statement as before:
SQL> SELECT TO_CHAR(salary,'L99G999D99') salary FROM employees;
You should see the same results as in Example 3–6:
SALARY
--------------------
€24.000,00
€17.000,00
€17.000,00
Example 3–8 NLS_LANGUAGE=GERMAN, NLS_TERRITORY=AMERICA
Use an ALTER SESSION statement to change the territory to America:
ALTER SESSION SET NLS_TERRITORY = America;
Sitzung wurde geändert.
Enter the same SELECT statement as in the other examples:
SQL> SELECT TO_CHAR(salary,'L99G999D99') salary FROM employees;
You should see results similar to the following output:
SALARY
--------------------
$24,000.00
$17,000.00
$17,000.00
Note that the currency symbol changed from € to $ because the territory changed from
Germany to America.
Overriding Default Values for NLS_LANGUAGE and NLS_TERRITORY During a
Session
Default values for NLS_LANGUAGE and NLS_TERRITORY and default values for
specific formatting parameters can be overridden during a session by using the ALTER
SESSION statement.
Example 3–9 NLS_LANG=ITALIAN_ITALY.WE8DEC
Set the NLS_LANG environment variable so that the language is Italian, the territory is
Italy, and the character set is WE8DEC:
% setenv NLS_LANG Italian_Italy.WE8DEC
See Also: "Overriding Default Values for NLS_LANGUAGE and
NLS_TERRITORY During a Session" on page 3-13 for more
information about using the ALTER SESSION statement
Language and Territory Parameters
3-14 Oracle Database Globalization Support Guide
Enter a SELECT statement:
SQL> SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees;
You should see results similar to the following output:
LAST_NAME HIRE_DATE SALARY
------------------------- --------- ----------
Sciarra 30-SET-97 962,5
Urman 07-MAR-98 975
Popp 07-DIC-99 862,5
Note the language of the month abbreviations and the decimal character.
Example 3–10 Change Language, Date Format, and Decimal Character
Use ALTER SESSION statements to change the language, the date format, and the
decimal character:
SQL> ALTER SESSION SET NLS_LANGUAGE=german;
Session wurde geändert.
SQL> ALTER SESSION SET NLS_DATE_FORMAT='DD.MON.YY';
Session wurde geändert.
SQL> ALTER SESSION SET NLS_NUMERIC_CHARACTERS='.,';
Session wurde geändert.
Enter the SELECT statement shown in Example 3–9:
SQL> SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees;
You should see results similar to the following output:
LAST_NAME HIRE_DATE SALARY
------------------------- --------- ----------
Sciarra 30.SEP.97 962.5
Urman 07.MÄR.98 975
Popp 07.DEZ.99 862.5
Note that the language of the month abbreviations is German and the decimal
character is a period.
The behavior of the NLS_LANG environment variable implicitly determines the
language environment of the database for each session. When a session connects to a
database, an ALTER SESSION statement is automatically executed to set the values of
the database parameters NLS_LANGUAGE and NLS_TERRITORY to those specified by
the language and territory arguments of NLS_LANG. If NLS_LANG is not defined,
then no implicit ALTER SESSION statement is executed.
When NLS_LANG is defined, the implicit ALTER SESSION is executed for all instances
to which the session connects, for both direct and indirect connections. If the values of
NLS parameters are changed explicitly with ALTER SESSION during a session, then
the changes are propagated to all instances to which that user session is connected.
Date and Time Parameters
Setting Up a Globalization Support Environment 3-15
Date and Time Parameters
Oracle Database enables you to control the display of date and time. This section
contains the following topics:
■Date Formats
■Time Formats
Date Formats
Different date formats are shown in Table 3–4.
This section includes the following parameters:
■NLS_DATE_FORMAT
■NLS_DATE_LANGUAGE
NLS_DATE_FORMAT
The NLS_DATE_FORMAT parameter defines the default date format to use with the
TO_CHAR and TO_DATE functions. The NLS_TERRITORY parameter determines the
default value of NLS_DATE_FORMAT. The value of NLS_DATE_FORMAT can be any
valid date format mask. For example:
NLS_DATE_FORMAT = "MM/DD/YYYY"
To add string literals to the date format, enclose the string literal with double quotes.
Note that when double quotes are included in the date format, the entire value must
be enclosed by single quotes. For example:
NLS_DATE_FORMAT = '"Date: "MM/DD/YYYY'
Example 3–11 Setting the Date Format to Display Roman Numerals
To set the default date format to display Roman numerals for the month, include the
following line in the initialization parameter file:
NLS_DATE_FORMAT = "DD RM YYYY"
Table 3–4 Date Formats
Country Description Example
Estonia dd.mm.yyyy 28.02.2003
Germany dd-mm-rr 28-02-03
Japan rr-mm-dd 03-02-28
UK dd-mon-rr 28-Feb-03
US dd-mon-rr 28-Feb-03
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, and ALTER
SESSION
Default value Derived from NLS_TERRITORY
Range of values Any valid date format mask
Date and Time Parameters
3-16 Oracle Database Globalization Support Guide
Enter the following SELECT statement:
SELECT TO_CHAR(SYSDATE) currdate FROM DUAL;
You should see the following output if today's date is February 12, 1997:
CURRDATE
---------
12 II 1997
The value of NLS_DATE_FORMAT is stored in the internal date format. Each format
element occupies two bytes, and each string occupies the number of bytes in the string
plus a terminator byte. Also, the entire format mask has a two-byte terminator. For
example, "MM/DD/YY" occupies 14 bytes internally because there are three format
elements (month, day, and year), two 3-byte strings (the two slashes), and the two-byte
terminator for the format mask. The format for the value of NLS_DATE_FORMAT
cannot exceed 24 bytes.
You can alter the default value of NLS_DATE_FORMAT by:
■Changing its value in the initialization parameter file and then restarting the
instance
■Using an ALTER SESSION SET NLS_DATE_FORMAT statement
If a table or index is partitioned on a date column, and if the date format specified by
NLS_DATE_FORMAT does not specify the first two digits of the year, then you must use
the TO_DATE function with a 4-character format mask for the year.
For example:
TO_DATE('11-jan-1997', 'dd-mon-yyyy')
NLS_DATE_LANGUAGE
The NLS_DATE_LANGUAGE parameter specifies the language for the day and month
names produced by the TO_CHAR and TO_DATE functions. NLS_DATE_LANGUAGE
overrides the language that is specified implicitly by NLS_LANGUAGE. NLS_DATE_
LANGUAGE has the same syntax as the NLS_LANGUAGE parameter, and all supported
languages are valid values.
NLS_DATE_LANGUAGE also determines the language used for:
■Month and day abbreviations returned by the TO_CHAR and TO_DATE functions
See Also: Oracle Database SQL Reference for more information
about date format elements and the ALTER SESSION statement
See Also: Oracle Database SQL Reference for more information
about partitioning tables and indexes and using TO_DATE
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, ALTER SESSION,
and SQL functions
Default value Derived from NLS_LANGUAGE
Range of values Any valid language name
Date and Time Parameters
Setting Up a Globalization Support Environment 3-17
■Month and day abbreviations used by the default date format (NLS_DATE_
FORMAT)
■Abbreviations for AM, PM, AD, and BC
Example 3–12 NLS_DATE_LANGUAGE=FRENCH, Month and Day Names
As an example of how to use NLS_DATE_LANGUAGE, set the date language to French:
ALTER SESSION SET NLS_DATE_LANGUAGE = FRENCH;
Enter a SELECT statement:
SELECT TO_CHAR(SYSDATE, 'Day:Dd Month yyyy') FROM DUAL;
You should see results similar to the following output:
TO_CHAR(SYSDATE,'DAY:DDMONTHYYYY')
------------------------------------------------------------
Vendredi:07 Décembre 2001
When numbers are spelled in words using the TO_CHAR function, the English spelling
is always used. For example, enter the following SELECT statement:
SQL> SELECT TO_CHAR(TO_DATE('12-Oct.-2001'),'Day: ddspth Month') FROM DUAL;
You should see results similar to the following output:
TO_CHAR(TO_DATE('12-OCT.-2001'),'DAY:DDSPTHMONTH')
--------------------------------------------------------------------
Vendredi: twelfth Octobre
Example 3–13 NLS_DATE_LANGUAGE=FRENCH, Month and Day Abbreviations
Month and day abbreviations are determined by NLS_DATE_LANGUAGE. Enter the
following SELECT statement:
SELECT TO_CHAR(SYSDATE, 'Dy:dd Mon yyyy') FROM DUAL;
You should see results similar to the following output:
TO_CHAR(SYSDATE,'DY:DDMO
------------------------
Ve:07 Déc. 2001
Example 3–14 NLS_DATE_LANGUAGE=FRENCH, Default Date Format
The default date format uses the month abbreviations determined by NLS_DATE_
LANGUAGE. For example, if the default date format is DD-MON-YYYY, then insert a date
as follows:
INSERT INTO tablename VALUES ('12-Févr.-1997');
Time Formats
Different time formats are shown in Table 3–5.
See Also: Oracle Database SQL Reference
Table 3–5 Time Formats
Country Description Example
Estonia hh24:mi:ss 13:50:23
Date and Time Parameters
3-18 Oracle Database Globalization Support Guide
This section contains information about the following parameters:
■NLS_TIMESTAMP_FORMAT
■NLS_TIMESTAMP_TZ_FORMAT
NLS_TIMESTAMP_FORMAT
NLS_TIMESTAMP_FORMAT defines the default date format for the TIMESTAMP and
TIMESTAMP WITH LOCAL TIME ZONE datatypes. The following example shows a
value for NLS_TIMESTAMP_FORMAT:
NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH:MI:SS.FF'
Example 3–15 Timestamp Format
SQL> SELECT TO_TIMESTAMP('11-nov-2000 01:00:00.336', 'dd-mon-yyyy hh:mi:ss.ff')
FROM DUAL;
You should see results similar to the following output:
TO_TIMESTAMP('11-NOV-200001:00:00.336','DD-MON-YYYYHH:MI:SS.FF')
---------------------------------------------------------------------------
2000-11-11 01:00:00.336000000
You can specify the value of NLS_TIMESTAMP_FORMAT by setting it in the
initialization parameter file. You can specify its value for a client as a client
environment variable.
You can also alter the value of NLS_TIMESTAMP_FORMAT by:
■Changing its value in the initialization parameter file and then restarting the
instance
■Using the ALTER SESSION SET NLS_TIMESTAMP_FORMAT statement
Germany hh24:mi:ss 13:50:23
Japan hh24:mi:ss 13:50:23
UK hh24:mi:ss 13:50:23
US hh:mi:ssxff am 1:50:23.555 PM
See Also: Chapter 4, "Datetime Datatypes and Time Zone
Support"
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, and ALTER
SESSION
Default value Derived from NLS_TERRITORY
Range of values Any valid datetime format mask
See Also: Oracle Database SQL Reference for more information
about the TO_TIMESTAMP function and the ALTER SESSION
statement
Table 3–5 (Cont.) Time Formats
Country Description Example
Calendar Definitions
Setting Up a Globalization Support Environment 3-19
NLS_TIMESTAMP_TZ_FORMAT
NLS_TIMESTAMP_TZ_FORMAT defines the default date format for the TIMESTAMP
and TIMESTAMP WITH LOCAL TIME ZONE datatypes. It is used with the TO_CHAR
and TO_TIMESTAMP_TZ functions.
You can specify the value of NLS_TIMESTAMP_TZ_FORMAT by setting it in the
initialization parameter file. You can specify its value for a client as a client
environment variable.
Example 3–16 Setting NLS_TIMESTAMP_TZ_FORMAT
The format value must be surrounded by quotation marks. For example:
NLS_TIMESTAMP_TZ_FORMAT = 'YYYY-MM-DD HH:MI:SS.FF TZH:TZM'
The following example of the TO_TIMESTAMP_TZ function uses the format value that
was specified for NLS_TIMESTAMP_TZ_FORMAT:
SQL> SELECT TO_TIMESTAMP_TZ('2000-08-20, 05:00:00.55 America/Los_Angeles',
'yyyy-mm-dd hh:mi:ss.ff TZR') FROM DUAL;
You should see results similar to the following output:
TO_TIMESTAMP_TZ('2000-08-20,05:00:00.55AMERICA/LOS_ANGELES','YYYY-MM-DDHH:M
---------------------------------------------------------------------------
2000-08-20 05:00:00.550000000 -07:00
You can change the value of NLS_TIMESTAMP_TZ_FORMAT by:
■Changing its value in the initialization parameter file and then restarting the
instance
■Using the ALTER SESSION statement.
Calendar Definitions
This section includes the following topics:
■Calendar Formats
■NLS_CALENDAR
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, and ALTER
SESSION
Default value Derived from NLS_TERRITORY
Range of values Any valid datetime format mask
See Also:
■Oracle Database SQL Reference for more information about the
TO_TIMESTAMP_TZ function and the ALTER SESSION
statement
■"Choosing a Time Zone File" on page 4-15 for more information
about time zones
Calendar Definitions
3-20 Oracle Database Globalization Support Guide
Calendar Formats
The following calendar information is stored for each territory:
■First Day of the Week
■First Calendar Week of the Year
■Number of Days and Months in a Year
■First Year of Era
First Day of the Week
Some cultures consider Sunday to be the first day of the week. Others consider
Monday to be the first day of the week. A German calendar starts with Monday, as
shown in Table 3–6.
The first day of the week is determined by the NLS_TERRITORY parameter.
First Calendar Week of the Year
Some countries use week numbers for scheduling, planning, and bookkeeping. Oracle
Database supports this convention. In the ISO standard, the week number can be
different from the week number of the calendar year. For example, 1st Jan 1988 is in
ISO week number 53 of 1987. An ISO week always starts on a Monday and ends on a
Sunday.
■If January 1 falls on a Friday, Saturday, or Sunday, then the ISO week that includes
January 1 is the last week of the previous year, because most of the days in the
week belong to the previous year.
■If January 1 falls on a Monday, Tuesday, Wednesday, or Thursday, then the ISO
week is the first week of the new year, because most of the days in the week
belong to the new year.
To support the ISO standard, Oracle Database provides the IW date format element. It
returns the ISO week number.
Table 3–7 shows an example in which January 1 occurs in a week that has four or more
days in the first calendar week of the year. The week containing January 1 is the first
ISO week of 1998.
Table 3–6 German Calendar Example: March 1998
Mo Di Mi Do Fr Sa So
------1
2345678
9101112131415
16 17 18 19 20 21 22
23 24 25 26 27 28 29
3031-----
See Also: "NLS_TERRITORY" on page 3-11
Table 3–7 First ISO Week of the Year: Example 1, January 1998
Mo Tu We Th Fr Sa Su ISO Week
- - - 1234 First ISO week of 1998
Calendar Definitions
Setting Up a Globalization Support Environment 3-21
Table 3–8 shows an example in which January 1 occurs in a week that has three or
fewer days in the first calendar week of the year. The week containing January 1 is the
53rd ISO week of 1998, and the following week is the first ISO week of 1999.
The first calendar week of the year is determined by the NLS_TERRITORY parameter.
Number of Days and Months in a Year
Oracle Database supports six calendar systems in addition to Gregorian, the default:
■Japanese Imperial—uses the same number of months and days as Gregorian, but
the year starts with the beginning of each Imperial Era
■ROC Official—uses the same number of months and days as Gregorian, but the
year starts with the founding of the Republic of China
■Persian—has 31 days for each of the first six months. The next five months have 30
days each. The last month has either 29 days or 30 days (leap year).
■Thai Buddha—uses a Buddhist calendar
■Arabic Hijrah—has 12 months with 354 or 355 days
■English Hijrah—has 12 months with 354 or 355 days
The calendar system is specified by the NLS_CALENDAR parameter.
First Year of Era
The Islamic calendar starts from the year of the Hegira.
The Japanese Imperial calendar starts from the beginning of an Emperor's reign. For
example, 1998 is the tenth year of the Heisei era. It should be noted, however, that the
Gregorian system is also widely understood in Japan, so both 98 and Heisei 10 can be
used to represent 1998.
567891011 Second ISO week of 1998
12 13 14 15 16 17 18 Third ISO week of 1998
19 20 21 22 23 24 25 Fourth ISO week of 1998
26 27 28 29 30 31 - Fifth ISO week of 1998
Table 3–8 First ISO Week of the Year: Example 2, January 1999
Mo Tu We Th Fr Sa Su ISO Week
----123Fifty-third ISO week of 1998
45678910First ISO week of 1999
11 12 13 14 15 16 17 Second ISO week of 1999
18 19 20 21 22 23 24 Third ISO week of 1999
25 26 27 28 29 30 31 Fourth ISO week of 1999
See Also: "NLS_TERRITORY" on page 3-11
See Also: "NLS_CALENDAR" on page 3-22
Table 3–7 (Cont.) First ISO Week of the Year: Example 1, January 1998
Mo Tu We Th Fr Sa Su ISO Week
Numeric and List Parameters
3-22 Oracle Database Globalization Support Guide
NLS_CALENDAR
Many different calendar systems are in use throughout the world. NLS_CALENDAR
specifies which calendar system Oracle Database uses.
NLS_CALENDAR can have one of the following values:
■Arabic Hijrah
■English Hijrah
■Gregorian
■Japanese Imperial
■Persian
■ROC Official (Republic of China)
■Thai Buddha
Example 3–17 NLS_CALENDAR='English Hijrah'
Set NLS_CALENDAR to English Hijrah.
SQL> ALTER SESSION SET NLS_CALENDAR='English Hijrah';
Enter a SELECT statement to display SYSDATE:
SELECT SYSDATE FROM DUAL;
You should see results similar to the following output:
SYSDATE
--------------------
24 Ramadan 1422
Numeric and List Parameters
This section includes the following topics:
■Numeric Formats
■NLS_NUMERIC_CHARACTERS
■NLS_LIST_SEPARATOR
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, ALTER SESSION,
and SQL functions
Default value Gregorian
Range of values Any valid calendar format name
See Also: Appendix A, "Locale Data" for a list of calendar
systems, their default date formats, and the character sets in which
dates are displayed
Numeric and List Parameters
Setting Up a Globalization Support Environment 3-23
Numeric Formats
The database must know the number-formatting convention used in each session to
interpret numeric strings correctly. For example, the database needs to know whether
numbers are entered with a period or a comma as the decimal character (234.00 or
234,00). Similarly, applications must be able to display numeric information in the
format expected at the client site.
Examples of numeric formats are shown in Table 3–9.
Numeric formats are derived from the setting of the NLS_TERRITORY parameter, but
they can be overridden by the NLS_NUMERIC_CHARACTERS parameter.
NLS_NUMERIC_CHARACTERS
This parameter specifies the decimal character and group separator. The group
separator is the character that separates integer groups to show thousands and
millions, for example. The group separator is the character returned by the G number
format mask. The decimal character separates the integer and decimal parts of a
number. Setting NLS_NUMERIC_CHARACTERS overrides the values derived from the
setting of NLS_TERRITORY.
Any character can be the decimal character or group separator. The two characters
specified must be single-byte, and the characters must be different from each other.
The characters cannot be any numeric character or any of the following characters:
plus (+), hyphen (-), less than sign (<), greater than sign (>). Either character can be a
space.
Example 3–18 Setting NLS_NUMERIC_CHARACTERS
To set the decimal character to a comma and the grouping separator to a period, define
NLS_NUMERIC_CHARACTERS as follows:
ALTER SESSION SET NLS_NUMERIC_CHARACTERS = ",.";
Table 3–9 Examples of Numeric Formats
Country Numeric Formats
Estonia 1 234 567,89
Germany 1.234.567,89
Japan 1,234,567.89
UK 1,234,567.89
US 1,234,567.89
See Also: "NLS_TERRITORY" on page 3-11
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, ALTER SESSION,
and SQL functions
Default value Default decimal character and group separator for a particular
territory
Range of values Any two valid numeric characters
Monetary Parameters
3-24 Oracle Database Globalization Support Guide
SQL statements can include numbers represented as numeric or text literals. Numeric
literals are not enclosed in quotes. They are part of the SQL language syntax and
always use a dot as the decimal character and never contain a group separator. Text
literals are enclosed in single quotes. They are implicitly or explicitly converted to
numbers, if required, according to the current NLS settings.
The following SELECT statement formats the number 4000 with the decimal character
and group separator specified in the ALTER SESSION statement:
SELECT TO_CHAR(4000, '9G999D99') FROM DUAL;
You should see results similar to the following output:
TO_CHAR(4
---------
4.000,00
You can change the default value of NLS_NUMERIC_CHARACTERS by:
■Changing the value of NLS_NUMERIC_CHARACTERS in the initialization
parameter file and then restarting the instance
■Using the ALTER SESSION statement to change the parameter's value during a
session
NLS_LIST_SEPARATOR
NLS_LIST_SEPARATOR specifies the character to use to separate values in a list of
values (usually , or . or ; or :). Its default value is derived from the value of NLS_
TERRITORY. For example, a list of numbers from 1 to 5 can be expressed as 1,2,3,4,5 or
1.2.3.4.5 or 1;2;3;4;5 or 1:2:3:4:5.
The character specified must be single-byte and cannot be the same as either the
numeric or monetary decimal character, any numeric character, or any of the following
characters: plus (+), hyphen (-), less than sign (<), greater than sign (>), period (.).
Monetary Parameters
This section includes the following topics:
■Currency Formats
■NLS_CURRENCY
■NLS_ISO_CURRENCY
■NLS_DUAL_CURRENCY
See Also: Oracle Database SQL Reference for more information
about the ALTER SESSION statement
Property Description
Parameter type String
Parameter scope Environment variable
Default value Derived from NLS_TERRITORY
Range of values Any valid character
Monetary Parameters
Setting Up a Globalization Support Environment 3-25
■NLS_MONETARY_CHARACTERS
■NLS_CREDIT
■NLS_DEBIT
Currency Formats
Different currency formats are used throughout the world. Some typical ones are
shown in Table 3–10.
NLS_CURRENCY
NLS_CURRENCY specifies the character string returned by the L number format mask,
the local currency symbol. Setting NLS_CURRENCY overrides the setting defined
implicitly by NLS_TERRITORY.
Example 3–19 Displaying the Local Currency Symbol
Connect to the sample order entry schema:
SQL> connect oe/oe
Connected.
Enter a SELECT statement similar to the following example:
SQL> SELECT TO_CHAR(order_total, 'L099G999D99') "total" FROM orders
WHERE order_id > 2450;
You should see results similar to the following output:
total
---------------------
$078,279.60
$006,653.40
$014,087.50
$010,474.60
$012,589.00
$000,129.00
Table 3–10 Currency Format Examples
Country Example
Estonia 1 234,56 kr
Germany 1.234,56€
Japan ¥1,234.56
UK £1,234.56
US $1,234.56
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, ALTER SESSION,
and SQL functions
Default value Derived from NLS_TERRITORY
Range of values Any valid currency symbol string
Monetary Parameters
3-26 Oracle Database Globalization Support Guide
$003,878.40
$021,586.20
You can change the default value of NLS_CURRENCY by:
■Changing its value in the initialization parameter file and then restarting the
instance
■Using an ALTER SESSION statement
NLS_ISO_CURRENCY
NLS_ISO_CURRENCY specifies the character string returned by the C number format
mask, the ISO currency symbol. Setting NLS_ISO_CURRENCY overrides the value
defined implicitly by NLS_TERRITORY.
Local currency symbols can be ambiguous. For example, a dollar sign ($) can refer to
US dollars or Australian dollars. ISO specifications define unique currency symbols for
specific territories or countries. For example, the ISO currency symbol for the US
dollar is USD. The ISO currency symbol for the Australian dollar is AUD.
More ISO currency symbols are shown in Table 3–11.
NLS_ISO_CURRENCY has the same syntax as the NLS_TERRITORY parameter, and all
supported territories are valid values.
Example 3–20 Setting NLS_ISO_CURRENCY
This example assumes that you are connected as oe/oe in the sample schema.
To specify the ISO currency symbol for France, set NLS_ISO_CURRENCY as follows:
ALTER SESSION SET NLS_ISO_CURRENCY = FRANCE;
Enter a SELECT statement:
See Also: Oracle Database SQL Reference for more information
about the ALTER SESSION statement
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, ALTER SESSION,
and SQL functions
Default value Derived from NLS_TERRITORY
Range of values Any valid string
Table 3–11 ISO Currency Examples
Country Example
Estonia 1 234 567,89 EEK
Germany 1.234.567,89 EUR
Japan 1,234,567.89 JPY
UK 1,234,567.89 GBP
US 1,234,567.89 USD
Monetary Parameters
Setting Up a Globalization Support Environment 3-27
SQL> SELECT TO_CHAR(order_total, 'C099G999D99') "TOTAL" FROM orders
WHERE customer_id = 146;
You should see results similar to the following output:
TOTAL
------------------
EUR017,848.20
EUR027,455.30
EUR029,249.10
EUR013,824.00
EUR000,086.00
You can change the default value of NLS_ISO_CURRENCY by:
■Changing its value in the initialization parameter file and then restarting the
instance
■Using an ALTER SESSION statement
NLS_DUAL_CURRENCY
Use NLS_DUAL_CURRENCY to override the default dual currency symbol defined
implicitly by NLS_TERRITORY.
NLS_DUAL_CURRENCY was introduced to support the euro currency symbol during
the euro transition period. See Table A–8, " Character Sets that Support the Euro
Symbol" for the character sets that support the euro symbol.
Oracle Database Support for the Euro
Twelve members of the European Monetary Union (EMU) have adopted the euro as
their currency. Setting NLS_TERRITORY to correspond to a country in the EMU
(Austria, Belgium, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the
Netherlands, Portugal, and Spain) results in the default values for NLS_CURRENCY
and NLS_DUAL_CURRENCY being set to EUR.
During the transition period (1999 through 2001), Oracle Database support for the euro
was provided in Oracle Database 8i and later as follows:
■NLS_CURRENCY was defined as the primary currency of the country
■NLS_ISO_CURRENCY was defined as the ISO currency code of a given territory
■NLS_DUAL_CURRENCY was defined as the secondary currency symbol (usually the
euro) for a given territory
See Also: Oracle Database SQL Reference for more information
about the ALTER SESSION statement
Property Description
Parameter type String
Parameter scope Initialization parameter, environmental variable, ALTER SESSION,
and SQL functions
Default value Derived from NLS_TERRITORY
Range of values Any valid symbol
Monetary Parameters
3-28 Oracle Database Globalization Support Guide
Beginning with Oracle Database 9i Release 2, the value of NLS_ISO_CURRENCY results
in the ISO currency symbol being set to EUR for EMU member countries who use the
euro. For example, suppose NLS_ISO_CURRENCY is set to FRANCE. Enter the
following SELECT statement:
SELECT TO_CHAR(order_total, 'C099G999D99') "TOTAL" FROM orders
WHERE customer_id=116;
You should see results similar to the following output:
TOTAL
-------
EUR006,394.80
EUR011,097.40
EUR014,685.80
EUR000,129.00
Customers who must retain their obsolete local currency symbol can override the
default for NLS_DUAL_CURRENCY or NLS_CURRENCY by defining them as parameters
in the initialization file on the server and as environment variables on the client.
It is not possible to override the ISO currency symbol that results from the value of
NLS_ISO_CURRENCY.
NLS_MONETARY_CHARACTERS
NLS_MONETARY_CHARACTERS specifies the character that separates groups of
numbers in monetary expressions. For example, when the territory is America, the
thousands separator is a comma, and the decimal separator is a period.
NLS_CREDIT
NLS_CREDIT sets the symbol that displays a credit in financial reports. The default
value of this parameter is determined by NLS_TERRITORY. For example, a space is a
valid value of NLS_CREDIT.
Note: NLS_LANG must also be set on the client for NLS_
CURRENCY or NLS_DUAL_CURRENCY to take effect.
Property Description
Parameter type String
Parameter scope Environment variable
Default value Derived from NLS_TERRITORY
Range of values Any valid character
Property Description
Parameter type String
Parameter scope Environment variable
Default value Derived from NLS_TERRITORY
Range of values Any string, maximum of 9 bytes (not including null)
Linguistic Sort Parameters
Setting Up a Globalization Support Environment 3-29
This parameter can be specified only in the client environment.
It can be retrieved through the OCIGetNlsInfo() function.
NLS_DEBIT
NLS_DEBIT sets the symbol that displays a debit in financial reports. The default
value of this parameter is determined by NLS_TERRITORY. For example, a minus sign
(-) is a valid value of NLS_DEBIT.
This parameter can be specified only in the client environment.
It can be retrieved through the OCIGetNlsInfo() function.
Linguistic Sort Parameters
You can choose how to sort data by using linguistic sort parameters.
This section includes the following topics:
■NLS_SORT
■NLS_COMP
NLS_SORT
NLS_SORT specifies the type of sort for character data. It overrides the default value
that is derived from NLS_LANGUAGE.
NLS_SORT contains either of the following values:
NLS_SORT = BINARY | sort_name
BINARY specifies a binary sort. sort_name specifies a linguistic sort sequence.
Example 3–21 Setting NLS_SORT
To specify the German linguistic sort sequence, set NLS_SORT as follows:
Property Description
Parameter type String
Parameter scope Environment variable
Default value Derived from NLS_TERRITORY
Range of values Any string, maximum or 9 bytes (not including null)
See Also: Chapter 5, "Linguistic Sorting and String Searching"
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, ALTER SESSION,
and SQL functions
Default value Derived from NLS_LANGUAGE
Range of values BINARY or any valid linguistic sort name
Linguistic Sort Parameters
3-30 Oracle Database Globalization Support Guide
NLS_SORT = German
You can alter the default value of NLS_SORT by:
■Changing its value in the initialization parameter file and then restarting the
instance
■Using an ALTER SESSION statement
NLS_COMP
The value of NLS_COMP affects the comparison behavior of SQL operations.
You can use NLS_COMP to avoid the cumbersome process of using the NLSSORT
function in SQL statements when you want to perform a linguistic comparison instead
of a binary comparison. When NLS_COMP is set to LINGUISTIC, SQL operations
perform a linguistic comparison based on the value of NLS_SORT. A setting of ANSI is
for backward compatibility; in general, you should set NLS_COMP to LINGUISTIC
when you want to perform a linguistic comparison.
Set NLS_COMP to LINGUISTIC as follows:
ALTER SESSION SET NLS_COMP = LINGUISTIC;
When NLS_COMP is set to LINGUISTIC, a linguistic index improves the performance
of the linguistic comparison. To enable a linguistic index, use the following syntax:
CREATE INDEX i ON t(NLSSORT(col, 'NLS_SORT=FRENCH'));
Note: When the NLS_SORT parameter is set to BINARY, the
optimizer can, in some cases, satisfy the ORDER BY clause without
doing a sort by choosing an index scan.
When NLS_SORT is set to a linguistic sort, a sort is needed to satisfy
the ORDER BY clause if there is no linguistic index for the linguistic
sort specified by NLS_SORT.
If a linguistic index exists for the linguistic sort specified by NLS_
SORT, then the optimizer can, in some cases, satisfy the ORDER BY
clause without doing a sort by choosing an index scan.
See Also:
■Chapter 5, "Linguistic Sorting and String Searching"
■Oracle Database SQL Reference for more information about the
ALTER SESSION statement
■"Linguistic Sorts" on page A-19 for a list of linguistic sort names
Property Description
Parameter type String
Parameter scope Initialization parameter, environment variable, and ALTER
SESSION
Default value BINARY
Range of values BINARY , LINGUISTIC, or ANSI
Length Semantics
Setting Up a Globalization Support Environment 3-31
Character Set Conversion Parameter
This section includes the following topic:
■NLS_NCHAR_CONV_EXCP
NLS_NCHAR_CONV_EXCP
NLS_NCHAR_CONV_EXCP determines whether an error is reported when there is data
loss during an implicit or explicit character type conversion between
NCHAR/NVARCHAR data and CHAR/VARCHAR2 data. The default value results in no
error being reported.
Length Semantics
This section includes the following topic:
■NLS_LENGTH_SEMANTICS
NLS_LENGTH_SEMANTICS
By default, the character datatypes CHAR and VARCHAR2 are specified in bytes, not
characters. Hence, the specification CHAR(20) in a table definition allows 20 bytes for
storing character data.
This works well if the database character set uses a single-byte character encoding
scheme because the number of characters is the same as the number of bytes. If the
database character set uses a multibyte character encoding scheme, then the number of
bytes no longer equals the number of characters because a character can consist of one
See Also:
■"Using Linguistic Sorts" on page 5-2
■"Using Linguistic Indexes" on page 5-17
Property Description
Parameter type String
Parameter scope Initialization parameter and ALTER SESSION
Default value FALSE
Range of values TRUE or FALSE
See Also: Chapter 11, "Character Set Migration" for more
information about data loss during character set conversion
Property Description
Parameter type String
Parameter scope Environment variable, initialization parameter, and ALTER
SESSION
Default value BYTE
Range of values BYTE or CHAR
Length Semantics
3-32 Oracle Database Globalization Support Guide
or more bytes. Thus, column widths must be chosen with care to allow for the
maximum possible number of bytes for a given number of characters. You can
overcome this problem by switching to character semantics when defining the column
size.
NLS_LENGTH_SEMANTICS enables you to create CHAR, VARCHAR2, and LONG columns
using either byte or character length semantics. NCHAR, NVARCHAR2, CLOB, and NCLOB
columns are always character-based. Existing columns are not affected.
You may be required to use byte semantics in order to maintain compatibility with
existing applications.
NLS_LENGTH_SEMANTICS does not apply to tables in SYS and SYSTEM. The data
dictionary always uses byte semantics.
Note that if the NLS_LENGTH_SEMANTICS environment variable is not set on the
client, then the client session defaults to the value for NLS_LENGTH_SEMANTICS on
the database server. This enables all client sessions on the network to have the same
NLS_LENGTH_SEMANTICS behavior. Setting the environment variable on an
individual client enables the server initialization parameter to be overridden for that
client.
See Also:
■"Length Semantics" on page 2-8
■Oracle Database Concepts for more information about length
semantics
Datetime Datatypes and Time Zone Support 4-1
4
Datetime Datatypes and Time Zone Support
This chapter includes the following topics:
■Overview of Datetime and Interval Datatypes and Time Zone Support
■Datetime and Interval Datatypes
■Datetime and Interval Arithmetic and Comparisons
■Datetime SQL Functions
■Datetime and Time Zone Parameters and Environment Variables
■Choosing a Time Zone File
■Upgrading the Time Zone File
■Setting the Database Time Zone
■Setting the Session Time Zone
■Converting Time Zones With the AT TIME ZONE Clause
■Support for Daylight Saving Time
Overview of Datetime and Interval Datatypes and Time Zone Support
Businesses conduct transactions across different time zones. Oracle Database datetime
and interval datatypes and time zone support make it possible to store consistent
information about the time of events and transactions.
Datetime and Interval Datatypes
The datetime datatypes are DATE, TIMESTAMP, TIMESTAMP WITH TIME ZONE, and
TIMESTAMP WITH LOCAL TIME ZONE. Values of datetime datatypes are sometimes
called datetimes.
The interval datatypes are INTERVAL YEAR TO MONTH and INTERVAL DAY TO
SECOND. Values of interval datatypes are sometimes called intervals.
Both datetimes and intervals are made up of fields. The values of these fields
determine the value of the datatype. The fields that apply to all Oracle Database
datetime and interval datatypes are:
Note: This chapter describes Oracle Database datetime and
interval datatypes. It does not attempt to describe ANSI datatypes
or other kinds of datatypes except when noted.
Datetime and Interval Datatypes
4-2 Oracle Database Globalization Support Guide
■YEAR
■MONTH
■DAY
■HOUR
■MINUTE
■SECOND
TIMESTAMP WITH TIME ZONE also includes these fields:
■TIMEZONE_HOUR
■TIMEZONE_MINUTE
■TIMEZONE_REGION
■TIMEZONE_ABBR
TIMESTAMP WITH LOCAL TIME ZONE does not store time zone information
internally, but you can see local time zone information in SQL output if the TZH:TZM
or TZR TZD format elements are specified.
The following sections describe the datetime datatypes and interval datatypes in more
detail:
■Datetime Datatypes
■Interval Datatypes
Datetime Datatypes
This section includes the following topics:
■DATE Datatype
■TIMESTAMP Datatype
■TIMESTAMP WITH TIME ZONE Datatype
■TIMESTAMP WITH LOCAL TIME ZONE Datatype
■Inserting Values into Datetime Datatypes
■Choosing a TIMESTAMP Datatype
DATE Datatype
The DATE datatype stores date and time information. Although date and time
information can be represented in both character and number datatypes, the DATE
datatype has special associated properties. For each DATE value, Oracle Database
stores the following information: century, year, month, date, hour, minute, and second.
You can specify a date value by:
■Specifying the date value as a literal
■Converting a character or numeric value to a date value with the TO_DATE
function
A date can be specified as an ANSI date literal or as an Oracle Database date value.
See Also: Oracle Database SQL Reference for the valid values of the
datetime and interval fields. Oracle Database SQL Reference also
contains information about format elements.
Datetime and Interval Datatypes
Datetime Datatypes and Time Zone Support 4-3
An ANSI date literal contains no time portion and must be specified in exactly the
following format:
DATE 'YYYY-MM-DD'
The following is an example of an ANSI date literal:
DATE '1998-12-25'
Alternatively, you can specify an Oracle Database date value as shown in the following
example:
TO_DATE('1998-DEC-25 17:30','YYYY-MON-DD HH24:MI','NLS_DATE_LANGUAGE=AMERICAN')
The default date format for an Oracle Database date value is derived from the NLS_
DATE_FORMAT and NLS_DATE_LANGUAGE initialization parameters. The date format
in the example includes a two-digit number for the day of the month, an abbreviation
of the month name, the last two digits of the year, and a 24-hour time designation. The
specification for NLS_DATE_LANGUAGE is included because 'DEC' is not a valid value
for MON in all locales.
Oracle Database automatically converts character values that are in the default date
format into date values when they are used in date expressions.
If you specify a date value without a time component, then the default time is
midnight. If you specify a date value without a date, then the default date is the first
day of the current month.
Oracle Database DATE columns always contain fields for both date and time. If your
queries use a date format without a time portion, then you must ensure that the time
fields in the DATE column are set to midnight. You can use the TRUNC (date) SQL
function to ensure that the time fields are set to midnight, or you can make the query a
test of greater than or less than (<, <=, >=, or >) instead of equality or inequality (= or
!=). Otherwise, Oracle Database may not return the query results you expect.
TIMESTAMP Datatype
The TIMESTAMP datatype is an extension of the DATE datatype. It stores year, month,
day, hour, minute, and second values. It also stores fractional seconds, which are not
stored by the DATE datatype.
Specify the TIMESTAMP datatype as follows:
TIMESTAMP [(fractional_seconds_precision)]
fractional_seconds_precision is optional and specifies the number of digits in
the fractional part of the SECOND datetime field. It can be a number in the range 0 to 9.
The default is 6.
For example, '26-JUN-02 09:39:16.78' shows 16.78 seconds. The fractional
seconds precision is 2 because there are 2 digits in '78'.
See Also:
■Oracle Database SQL Reference for more information about the
DATE datatype
■"NLS_DATE_FORMAT" on page 3-15
■"NLS_DATE_LANGUAGE" on page 3-16
■Oracle Database SQL Reference for more information about
literals, format elements such as MM, and the TO_DATE function
Datetime and Interval Datatypes
4-4 Oracle Database Globalization Support Guide
You can specify the TIMESTAMP literal in a format like the following:
TIMESTAMP 'YYYY-MM-DD HH24:MI:SS.FF'
Using the example format, specify TIMESTAMP as a literal as follows:
TIMESTAMP '1997-01-31 09:26:50.12'
The value of NLS_TIMESTAMP_FORMAT initialization parameter determines the
timestamp format when a character string is converted to the TIMESTAMP datatype.
NLS_DATE_LANGUAGE determines the language used for character data such as MON.
TIMESTAMP WITH TIME ZONE Datatype
TIMESTAMP WITH TIME ZONE is a variant of TIMESTAMP that includes a time zone
region name or time zone offset in its value. The time zone offset is the difference (in
hours and minutes) between local time and UTC (Coordinated Universal Time,
formerly Greenwich Mean Time). Specify the TIMESTAMP WITH TIME ZONE
datatype as follows:
TIMESTAMP [(fractional_seconds_precision)] WITH TIME ZONE
fractional_seconds_precision is optional and specifies the number of digits in
the fractional part of the SECOND datetime field.
You can specify TIMESTAMP WITH TIME ZONE as a literal as follows:
TIMESTAMP '1997-01-31 09:26:56.66 +02:00'
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. For
example, the following expressions have the same value:
TIMESTAMP '1999-01-15 8:00:00 -8:00'
TIMESTAMP '1999-01-15 11:00:00 -5:00'
You can replace the UTC offset with the TZR (time zone region) format element. The
following expression specifies US/Pacific for the time zone region:
TIMESTAMP '1999-01-15 8:00:00 US/Pacific'
To eliminate the ambiguity of boundary cases when the time switches from Standard
Time to Daylight Saving Time, use both the TZR format element and the corresponding
TZD format element. The TZD format element is an abbreviation of the time zone
region with Daylight Saving Time information included. Examples are PST for
US/Pacific standard time and PDT for US/Pacific daylight time. The following
specification ensures that a Daylight Saving Time value is returned:
TIMESTAMP '1999-10-29 01:30:00 US/Pacific PDT'
If you do not add the TZD format element, and the datetime value is ambiguous, then
Oracle Database returns an error if you have the ERROR_ON_OVERLAP_TIME session
parameter set to TRUE. If ERROR_ON_OVERLAP_TIME is set to FALSE (the default
value), then Oracle Database interprets the ambiguous datetime as Standard Time.
See Also:
■Oracle Database SQL Reference for more information about the
TIMESTAMP datatype
■"NLS_TIMESTAMP_FORMAT" on page 3-18
■"NLS_DATE_LANGUAGE" on page 3-16
Datetime and Interval Datatypes
Datetime Datatypes and Time Zone Support 4-5
The default date format for the TIMESTAMP WITH TIME ZONE datatype is
determined by the value of the NLS_TIMESTAMP_TZ_FORMAT initialization
parameter.
TIMESTAMP WITH LOCAL TIME ZONE Datatype
TIMESTAMP WITH LOCAL TIME ZONE is another variant of TIMESTAMP. It differs
from TIMESTAMP WITH TIME ZONE as follows: data stored in the database is
normalized to the database time zone, and the time zone offset is not stored as part of
the column data. When users retrieve the data, Oracle Database returns it in the users'
local session time zone. The time zone offset is the difference (in hours and minutes)
between local time and UTC (Coordinated Universal Time, formerly Greenwich Mean
Time).
Specify the TIMESTAMP WITH LOCAL TIME ZONE datatype as follows:
TIMESTAMP [(fractional_seconds_precision)] WITH LOCAL TIME ZONE
fractional_seconds_precision is optional and specifies the number of digits in
the fractional part of the SECOND datetime field.
There is no literal for TIMESTAMP WITH LOCAL TIME ZONE, but TIMESTAMP literals
and TIMESTAMP WITH TIME ZONE literals can be inserted into a TIMESTAMP WITH
LOCAL TIME ZONE column.
The default date format for TIMESTAMP WITH LOCAL TIME ZONE is determined by
the value of the NLS_TIMESTAMP_FORMAT initialization parameter.
Inserting Values into Datetime Datatypes
You can insert values into a datetime column in the following ways:
■Insert a character string whose format is based on the appropriate NLS format
value
■Insert a literal
See Also:
■Oracle Database SQL Reference for more information about the
TIMESTAMP WITH TIME ZONE datatype
■"TIMESTAMP Datatype" on page 4-3 for more information
about fractional seconds precision
■"Support for Daylight Saving Time" on page 4-23
■"NLS_TIMESTAMP_TZ_FORMAT" on page 3-19
■Oracle Database SQL Reference for more information about
format elements
■Oracle Database SQL Reference for more information about
setting the ERROR_ON_OVERLAP_TIME session parameter
See Also:
■Oracle Database SQL Reference for more information about the
TIMESTAMP WITH LOCAL TIME ZONE datatype
■"TIMESTAMP Datatype" on page 4-3 for more information
about fractional seconds precision
■"NLS_TIMESTAMP_FORMAT" on page 3-18
Datetime and Interval Datatypes
4-6 Oracle Database Globalization Support Guide
■Insert a literal for which implicit conversion is performed
■Use the TO_TIMESTAMP, TO_TIMESTAMP_TZ, or TO_DATE SQL function
The following examples show how to insert data into datetime datatypes.
Example 4–1 Inserting Data into a DATE Column
Set the date format.
SQL> ALTER SESSION SET NLS_DATE_FORMAT='DD-MON-YYYY HH24:MI:SS';
Create a table table_dt with columns c_id and c_dt. The c_id column is of
NUMBER datatype and helps to identify the method by which the data is entered. The
c_dt column is of DATE datatype.
SQL> CREATE TABLE table_dt (c_id NUMBER, c_dt DATE);
Insert a date as a character string.
SQL> INSERT INTO table_dt VALUES(1, '01-JAN-2003');
Insert the same date as a DATE literal.
SQL> INSERT INTO table_dt VALUES(2, DATE '2003-01-01');
Insert the date as a TIMESTAMP literal. Oracle Database drops the time zone
information.
SQL> INSERT INTO table_dt VALUES(3, TIMESTAMP '2003-01-01 00:00:00 US/Pacific');
Insert the date with the TO_DATE function.
SQL> INSERT INTO table_dt VALUES(4, TO_DATE('01-JAN-2003', 'DD-MON-YYYY'));
Display the data.
SQL> SELECT * FROM table_dt;
C_ID C_DT
---------- --------------------
1 01-JAN-2003 00:00:00
2 01-JAN-2003 00:00:00
3 01-JAN-2003 00:00:00
4 01-JAN-2003 00:00:00
Example 4–2 Inserting Data into a TIMESTAMP Column
Set the timestamp format.
SQL> ALTER SESSION SET NLS_TIMESTAMP_FORMAT='DD-MON-YY HH:MI:SSXFF';
Create a table table_ts with columns c_id and c_ts. The c_id column is of
NUMBER datatype and helps to identify the method by which the data is entered. The
c_ts column is of TIMESTAMP datatype.
SQL> CREATE TABLE table_ts(c_id NUMBER, c_ts TIMESTAMP);
Insert a date and time as a character string.
SQL> INSERT INTO table_ts VALUES(1, '01-JAN-2003 2:00:00');
Insert the same date and time as a TIMESTAMP literal.
SQL> INSERT INTO table_ts VALUES(2, TIMESTAMP '2003-01-01 2:00:00');
Datetime and Interval Datatypes
Datetime Datatypes and Time Zone Support 4-7
Insert the same date and time as a TIMESTAMP WITH TIME ZONE literal. Oracle
Database converts it to a TIMESTAMP value, which means that the time zone
information is dropped.
SQL> INSERT INTO table_ts VALUES(3, TIMESTAMP '2003-01-01 2:00:00 -08:00');
Display the data.
SQL> SELECT * FROM table_ts;
C_ID C_TS
---------- -----------------------------
1 01-JAN-03 02:00:00.000000 AM
2 01-JAN-03 02:00:00.000000 AM
3 01-JAN-03 02:00:00.000000 AM
Note that the three methods result in the same value being stored.
Example 4–3 Inserting Data into the TIMESTAMP WITH TIME ZONE Datatype
Set the timestamp format.
SQL> ALTER SESSION SET NLS_TIMESTAMP_TZ_FORMAT='DD-MON-RR HH:MI:SSXFF AM TZR';
Set the time zone to '-07:00'.
SQL> ALTER SESSION SET TIME_ZONE='-7:00';
Create a table table_tstz with columns c_id and c_tstz. The c_id column is of
NUMBER datatype and helps to identify the method by which the data is entered. The
c_tstz column is of TIMESTAMP WITH TIME ZONE datatype.
SQL> CREATE TABLE table_tstz (c_id NUMBER, c_tstz TIMESTAMP WITH TIME ZONE);
Insert a date and time as a character string.
SQL> INSERT INTO table_tstz VALUES(1, '01-JAN-2003 2:00:00 AM -07:00');
Insert the same date and time as a TIMESTAMP literal. Oracle Database converts it to a
TIMESTAMP WITH TIME ZONE literal, which means that the session time zone is
appended to the TIMESTAMP value.
SQL> INSERT INTO table_tstz VALUES(2, TIMESTAMP '2003-01-01 2:00:00');
Insert the same date and time as a TIMESTAMP WITH TIME ZONE literal.
SQL> INSERT INTO table_tstz VALUES(3, TIMESTAMP '2003-01-01 2:00:00 -8:00');
Display the data.
SQL> SELECT * FROM table_tstz;
C_ID C_TSTZ
---------- ------------------------------------
1 01-JAN-03 02:00.00:000000 AM -07:00
2 01-JAN-03 02:00:00.000000 AM -07:00
3 01-JAN-03 02:00:00.000000 AM -08:00
Note that the time zone is different for method 3, because the time zone information
was specified as part of the TIMESTAMP WITH TIME ZONE literal.
Datetime and Interval Datatypes
4-8 Oracle Database Globalization Support Guide
Example 4–4 Inserting Data into the TIMESTAMP WITH LOCAL TIME ZONE Datatype
Consider data that is being entered in Denver, Colorado, U.S.A., whose time zone is
UTC-7.
SQL> ALTER SESSION SET TIME_ZONE='-07:00';
Create a table table_tsltz with columns c_id and c_tsltz. The c_id column is
of NUMBER datatype and helps to identify the method by which the data is entered.
The c_tsltz column is of TIMESTAMP WITH LOCAL TIME ZONE datatype.
SQL> CREATE TABLE table_tsltz (c_id NUMBER, c_tsltz TIMESTAMP WITH LOCAL TIME ZONE);
Insert a date and time as a character string.
SQL> INSERT INTO table_tsltz VALUES(1, '01-JAN-2003 2:00:00');
Insert the same data as a TIMESTAMP WITH LOCAL TIME ZONE literal.
SQL> INSERT INTO table_tsltz VALUES(2, TIMESTAMP '2003-01-01 2:00:00');
Insert the same data as a TIMESTAMP WITH TIME ZONE literal. Oracle Database
converts the data to a TIMESTAMP WITH LOCAL TIME ZONE value. This means the
time zone that is entered (-08:00) is converted to the session time zone value
(-07:00).
SQL> INSERT INTO table_tsltz VALUES(3, TIMESTAMP '2003-01-01 2:00:00 -08:00');
Display the data.
SQL> SELECT * FROM table_tsltz;
C_ID C_TSLTZ
---------- ------------------------------------
1 01-JAN-03 02.00.00.000000 AM
2 01-JAN-03 02.00.00.000000 AM
3 01-JAN-03 03.00.00.000000 AM
Note that the information that was entered as UTC-8 has been changed to the local
time zone, changing the hour from 2 to 3.
Choosing a TIMESTAMP Datatype
Use the TIMESTAMP datatype when you need a datetime value without locale
information. For example, you can store information about the times when workers
punch a timecard in and out of their assembly line workstations. The TIMESTAMP
datatype uses 7 or 11 bytes of storage.
Use the TIMESTAMP WITH TIME ZONE datatype when the application is used across
time zones. Consider a banking company with offices around the world. It records a
deposit to an account at 11 a.m. in London and a withdrawal of the same amount from
the account at 9 a.m. in New York. The money is in the account for three hours. Unless
time zone information is stored with the account transactions, it appears that the
account is overdrawn from 9 a.m. to 11 a.m.
The TIMESTAMP WITH TIME ZONE datatype requires 13 bytes of storage, or two
more bytes of storage than the TIMESTAMP and TIMESTAMP WITH LOCAL TIME
ZONE datatypes because it stores time zone information. The time zone is stored as an
See Also: "Datetime SQL Functions" on page 4-12 for more
information about the TO_TIMESTAMP or TO_TIMESTAMP_TZ SQL
functions
Datetime and Interval Datatypes
Datetime Datatypes and Time Zone Support 4-9
offset from UTC or as a time zone region name. The data is available for display or
calculations without additional processing. A TIMESTAMP WITH TIME ZONE column
cannot be used as a primary key. If an index is created on a TIMESTAMP WITH TIME
ZONE column, it becomes a function-based index.
The TIMESTAMP WITH LOCAL TIME ZONE datatype stores the timestamp without
time zone information. It normalizes the data to the database time zone every time the
data is sent to and from a client. It requires 11 bytes of storage.
The TIMESTAMP WITH LOCAL TIME ZONE datatype is appropriate when the
original time zone is of no interest, but the relative times of events are important.
Consider the transactions described in the previous banking example. Suppose the
data is recorded using the TIMESTAMP WITH LOCAL TIME ZONE datatype. If the
database time zone of the bank is set to Asia/Hong_Kong, then an employee in Hong
Kong who displays the data would see that the deposit was made at 7 p.m. and the
withdrawal was made at 10 p.m. If the same data is displayed in London, it would
show that the deposit was made at 11 a.m. and the withdrawal was made at 2 p.m. The
three-hour difference is preserved, but the time zone/region of the original transaction
is not. Because of this, the actual time of the transaction can be interpreted differently
depending on the time zone/region from which the information is retrieved. For
example, in London, the transactions appear to be conducted within business hours,
in Hong Kong, they do not.
Note that, because the original time zone region of the time data is not preserved in
the TIMESTAMP WITH LOCAL TIME ZONE data type, time data referring to times from
regions such as Brazil and Israel, regions that update their Daylight Savings Transition
dates frequently and at irregular periods, may be inaccurate. If time information from
these regions is key to your application, you may wish to consider using one of the
other datetime types.
Interval Datatypes
Interval datatypes store time durations. They are used primarily with analytic
functions. For example, you can use them to calculate a moving average of stock
prices. You must use interval datatypes to determine the values that correspond to a
particular percentile. You can also use interval datatypes to update historical tables.
This section includes the following topics:
■INTERVAL YEAR TO MONTH Datatype
■INTERVAL DAY TO SECOND Datatype
■Inserting Values into Interval Datatypes
INTERVAL YEAR TO MONTH Datatype
INTERVAL YEAR TO MONTH stores a period of time using the YEAR and MONTH
datetime fields. Specify INTERVAL YEAR TO MONTH as follows:
INTERVAL YEAR [(year_precision)] TO MONTH
year_precision is the number of digits in the YEAR datetime field. Accepted values
are 0 to 9. The default value of year_precision is 2.
See Also: Oracle Data Warehousing Guide for more information
about analytic functions, including moving averages and inverse
percentiles
Datetime and Interval Arithmetic and Comparisons
4-10 Oracle Database Globalization Support Guide
Interval values can be specified as literals. There are many ways to specify interval
literals.The following is one example of specifying an interval of 123 years and 2
months.The year precision is 3.
INTERVAL '123-2' YEAR(3) TO MONTH
INTERVAL DAY TO SECOND Datatype
INTERVAL DAY TO SECOND stores a period of time in terms of days, hours, minutes,
and seconds. Specify this datatype as follows:
INTERVAL DAY [(day_precision)] TO SECOND [(fractional_seconds_precision)]
day_precision is the number of digits in the DAY datetime field. 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 default is 6.
The following is one example of specifying an interval of 4 days, 5 hours, 12 minutes,
10 seconds, and 222 thousandths of a second. The fractional second precision is 3.
INTERVAL '4 5:12:10.222' DAY TO SECOND(3)
Interval values can be specified as literals. There are many ways to specify interval
literals.
Inserting Values into Interval Datatypes
You can insert values into an interval column in the following ways:
■Insert an interval as a literal. For example:
INSERT INTO table1 VALUES (INTERVAL '4-2' YEAR TO MONTH);
This statement inserts an interval of 4 years and 2 months.
Oracle Database recognizes literals for other ANSI interval types and converts the
values to Oracle Database interval values.
■Use the NUMTODSINTERVAL, NUMTOYMINTERVAL, TO_DSINTERVAL, and TO_
YMINTERVAL SQL functions.
Datetime and Interval Arithmetic and Comparisons
This section includes the following topics:
■Datetime and Interval Arithmetic
■Datetime Comparisons
■Explicit Conversion of Datetime Datatypes
See Also: Oracle Database SQL Reference for more information
about specifying interval literals with the INTERVAL YEAR TO
MONTH datatype
See Also: Oracle Database SQL Reference for more information
about specifying interval literals with the INTERVAL DAY TO
SECOND datatype
See Also: "Datetime SQL Functions" on page 4-12
Datetime and Interval Arithmetic and Comparisons
Datetime Datatypes and Time Zone Support 4-11
Datetime and Interval Arithmetic
You can perform arithmetic operations on date (DATE), timestamp (TIMESTAMP,
TIMESTAMP WITH TIME ZONE, and TIMESTAMP WITH LOCAL TIME ZONE) and
interval (INTERVAL DAY TO SECOND and INTERVAL YEAR TO MONTH) data. You
can maintain the most precision in arithmetic operations by using a timestamp
datatype with an interval datatype.
You can use NUMBER constants in arithmetic operations on date and timestamp values.
Oracle Database internally converts timestamp values to date values before doing
arithmetic operations on them with NUMBER constants. This means that information
about fractional seconds is lost during operations that include both date and
timestamp values. Oracle Database interprets NUMBER constants in datetime and
interval expressions as number of days.
Each DATE value contains a time component. The result of many date operations
includes a fraction. This fraction means a portion of one day. For example, 1.5 days is
36 hours. These fractions are also returned by Oracle Database built-in SQL functions
for common operations on DATE data. For example, the built-in MONTHS_BETWEEN
SQL function returns the number of months between two dates. The fractional portion
of the result represents that portion of a 31-day month.
Oracle Database performs all timestamp arithmetic in UTC time. For TIMESTAMP
WITH LOCAL TIME ZONE data, Oracle Database converts the datetime value from the
database time zone to UTC and converts back to the database time zone after
performing the arithmetic. For TIMESTAMP WITH TIME ZONE data, the datetime
value is always in UTC, so no conversion is necessary.
Datetime Comparisons
When you compare date and timestamp values, Oracle Database converts the data to
the more precise datatype before doing the comparison. For example, if you compare
data of TIMESTAMP WITH TIME ZONE datatype with data of TIMESTAMP datatype,
Oracle Database converts the TIMESTAMP data to TIMESTAMP WITH TIME ZONE,
using the session time zone.
The order of precedence for converting date and timestamp data is as follows:
1. DATE
2. TIMESTAMP
3. TIMESTAMP WITH LOCAL TIME ZONE
4. TIMESTAMP WITH TIME ZONE
For any pair of datatypes, Oracle Database converts the datatype that has a smaller
number in the preceding list to the datatype with the larger number.
Explicit Conversion of Datetime Datatypes
If you want to do explicit conversion of datetime datatypes, use the CAST SQL
function. You can explicitly convert DATE, TIMESTAMP, TIMESTAMP WITH TIME
ZONE, and TIMESTAMP WITH LOCAL TIME ZONE to another datatype in the list.
See Also:
■Oracle Database SQL Reference for detailed information about
datetime and interval arithmetic operations
■"Datetime SQL Functions" on page 4-12 for information about
which functions cause implicit conversion to DATE
Datetime SQL Functions
4-12 Oracle Database Globalization Support Guide
Datetime SQL Functions
Datetime functions operate on date (DATE), timestamp (TIMESTAMP, TIMESTAMP
WITH TIME ZONE, and TIMESTAMP WITH LOCAL TIME ZONE) and interval
(INTERVAL DAY TO SECOND, INTERVAL YEAR TO MONTH) values.
Some of the datetime functions were designed for the Oracle Database DATE datatype.
If you provide a timestamp value as their argument, then Oracle Database internally
converts the input type to a DATE value. Oracle Database does not perform internal
conversion for the ROUND and TRUNC functions.
Table 4–1 shows the datetime functions that were designed for the Oracle Database
DATE datatype. For more detailed descriptions, refer to Oracle Database SQL Reference.
Table 4–2 describes additional datetime functions. For more detailed descriptions, refer
to Oracle Database SQL Reference.
See Also: Oracle Database SQL Reference
Table 4–1 Datetime Functions Designed for the DATE Datatype
Function Description
ADD_MONTHS Returns the date d plus n months
LAST_DAY Returns the last day of the month that contains date
MONTHS_BETWEEN Returns the number of months between date1 and date2
NEW_TIME Returns the date and time in zone2 time zone when the date
and time in zone1 time zone are date
Note: This function takes as input only a limited number of
time zones. You can have access to a much greater number of
time zones by combining the FROM_TZ function and the
datetime expression.
NEXT_DAY Returns the date of the first weekday named by char that is
later than date
ROUND (date) Returns date rounded to the unit specified by the fmt format
model
TRUNC (date) Returns date with the time portion of the day truncated to the
unit specified by the fmt format model
Table 4–2 Additional Datetime Functions
Datetime Function Description
CURRENT_DATE Returns the current date in the session time zone in a value in the
Gregorian calendar, of the DATE datatype
CURRENT_TIMESTAMP Returns the current date and time in the session time zone as a
TIMESTAMP WITH TIME ZONE value
DBTIMEZONE Returns the value of the database time zone. The value is a time
zone offset or a time zone region name
EXTRACT (datetime) Extracts and returns the value of a specified datetime field from a
datetime or interval value expression
FROM_TZ Converts a TIMESTAMP value at a time zone to a TIMESTAMP
WITH TIME ZONE value
Datetime and Time Zone Parameters and Environment Variables
Datetime Datatypes and Time Zone Support 4-13
Datetime and Time Zone Parameters and Environment Variables
This section includes the following topics:
■Datetime Format Parameters
■Time Zone Environment Variables
■Daylight Saving Time Session Parameter
Datetime Format Parameters
Table 4–3 contains the names and descriptions of the datetime format parameters.
LOCALTIMESTAMP Returns the current date and time in the session time zone in a
value of the TIMESTAMP datatype
NUMTODSINTERVAL Converts number n to an INTERVAL DAY TO SECOND literal
NUMTOYMINTERVAL Converts number n to an INTERVAL YEAR TO MONTH literal
SESSIONTIMEZONE Returns the value of the current session's time zone
SYS_EXTRACT_UTC Extracts the UTC from a datetime with time zone offset
SYSDATE Returns the date and time of the operating system on which the
database resides, taking into account the time zone of the database
server's operating system that was in effect when the database
was started
SYSTIMESTAMP Returns the system date, including fractional seconds and time
zone of the system on which the database resides
TO_CHAR (datetime) Converts a datetime or interval value of DATE, TIMESTAMP,
TIMESTAMP WITH TIME ZONE, or TIMESTAMP WITH LOCAL
TIME ZONE datatype to a value of VARCHAR2 datatype in the
format specified by the fmt date format
TO_DSINTERVAL Converts a character string of CHAR, VARCHAR2, NCHAR, or
NVARCHAR2 datatype to a value of INTERVAL DAY TO SECOND
datatype
TO_NCHAR (datetime) Converts a datetime or interval value of DATE, TIMESTAMP,
TIMESTAMP WITH TIME ZONE, TIMESTAMP WITH LOCAL
TIME ZONE, INTERVAL MONTH TO YEAR, or INTERVAL DAY
TO SECOND datatype from the database character set to the
national character set
TO_TIMESTAMP Converts a character string of CHAR, VARCHAR2, NCHAR, or
NVARCHAR2 datatype to a value of TIMESTAMP datatype
TO_TIMESTAMP_TZ Converts a character string of CHAR, VARCHAR2, NCHAR, or
NVARCHAR2 datatype to a value of the TIMESTAMP WITH TIME
ZONE datatype
TO_YMINTERVAL Converts a character string of CHAR, VARCHAR2, NCHAR, or
NVARCHAR2 datatype to a value of the INTERVAL YEAR TO
MONTH datatype
TZ_OFFSET Returns the time zone offset that corresponds to the entered value,
based on the date that the statement is executed
See Also: Oracle Database SQL Reference
Table 4–2 (Cont.) Additional Datetime Functions
Datetime Function Description
Datetime and Time Zone Parameters and Environment Variables
4-14 Oracle Database Globalization Support Guide
Their default values are derived from NLS_TERRITORY.
You can specify their values by setting them in the initialization parameter file. You
can specify their values for a client as client environment variables.
You can also change their values by changing their value in the initialization
parameter file and then restarting the instance.
To change their values during a session, use the ALTER SESSION statement.
Time Zone Environment Variables
The time zone environment variables are:
■ORA_TZFILE, which specifies the Oracle Database time zone file used by the
database
■ORA_SDTZ, which specifies the default session time zone
Daylight Saving Time Session Parameter
ERROR_ON_OVERLAP_TIME is a session parameter that determines how Oracle
Database handles an ambiguous datetime boundary value. Ambiguous datetime
values can occur when the time changes between Daylight Saving Time and standard
time.
The possible values are TRUE and FALSE. When ERROR_ON_OVERLAP_TIME is TRUE,
then an error is returned when Oracle Database encounters an ambiguous datetime
value. When ERROR_ON_OVERLAP_TIME is FALSE, then ambiguous datetime values
are assumed to be the standard time representation for the region. The default value is
FALSE.
Table 4–3 Datetime Format Parameters
Parameter Description
NLS_DATE_FORMAT Defines the default date format to use with the TO_CHAR and
TO_DATE functions
NLS_TIMESTAMP_FORMAT Defines the default timestamp format to use with the TO_
CHAR and TO_TIMESTAMP functions
NLS_TIMESTAMP_TZ_FORMAT Defines the default timestamp with time zone format to use
with the TO_CHAR and TO_TIMESTAMP_TZ functions
See Also:
■"Date and Time Parameters" on page 3-15 for more information,
including examples
■"NLS_DATE_FORMAT" on page 3-15
■"NLS_TIMESTAMP_FORMAT" on page 3-18
■"NLS_TIMESTAMP_TZ_FORMAT" on page 3-19
See Also:
■"Choosing a Time Zone File" on page 4-15
■"Setting the Session Time Zone" on page 4-21
See Also: "Support for Daylight Saving Time" on page 4-23
Choosing a Time Zone File
Datetime Datatypes and Time Zone Support 4-15
Choosing a Time Zone File
The Oracle Database time zone files contain the valid time zone names. The following
information is also included for each time zone:
■Offset from Coordinated Universal Time (UTC)
■Transition times for Daylight Saving Time
■Abbreviations for standard time and Daylight Saving Time
Two time zone files are included in the Oracle Database home directory. The default
time zone file is $ORACLE_HOME/oracore/zoneinfo/timezonelrg.dat, which
contains all the time zones defined in the database. $ORACLE_
HOME/oracore/zoneinfo/timezone.dat contains only the most commonly used
time zones.
If you use the larger time zone file, then you must continue to use it unless you are
sure that none of the additional time zones that it contains are used for data that is
stored in the database. Also, all databases and client installations that share
information must use the same time zone file.
To enable the use of $ORACLE_HOME/oracore/zoneinfo/timezone.dat, or if
you are already using it as your time zone file and you want to continue to do so in an
Oracle Database 11g environment, perform the following steps:
1. Shut down the database if it has been started.
2. Set the ORA_TZFILE environment variable to $ORACLE_
HOME/oracore/zoneinfo/timezone.dat.
3. Restart the database.
Oracle Database time zone data is derived from the public domain information
available at ftp://elsie.nci.nih.gov/pub/. Oracle Database time zone data
may not reflect the most recent data available at this site.
You can obtain a list of time zone names and time zone abbreviations from the time
zone file that is installed with your database by entering the following statement:
SELECT tzname, tzabbrev FROM V$TIMEZONE_NAMES;
For the default time zone file, this statement results in output similar to the following:
TZNAME TZABBREV
-------------------- ----------
Africa/Algiers LMT
Africa/Algiers PMT
Africa/Algiers WET
Africa/Algiers WEST
Africa/Algiers CET
Africa/Algiers CEST
Africa/Cairo LMT
Africa/Cairo EET
Africa/Cairo EEST
Africa/Casablanca LMT
Note: If you are already using the default time zone file, then it is
not practical to change to the smaller time zone file because the
database may contain data with time zones that are not part of the
smaller time zone file.
Choosing a Time Zone File
4-16 Oracle Database Globalization Support Guide
Africa/Casablanca WET
Africa/Casablanca WEST
Africa/Casablanca CET
...
W-SU LMT
W-SU MMT
W-SU MST
W-SU MDST
W-SU S
W-SU MSD
W-SU MSK
W-SU EET
W-SU EEST
WET LMT
WET WEST
WET WET
1393 rows selected.
There are 6 time zone abbreviations associated with the Africa/Algiers time zone, 3
abbreviations associated with the Africa/Cairo time zone, and 4 abbreviations
associated with the Africa/Casablanca time zone. The following table shows the time
zone abbreviations and their meanings.
Note that an abbreviation can be associated with more than one time zone. For
example, CET is associated with both Africa/Algiers and Africa/Casablanca, as well
as time zones in Europe.
If you want a list of time zones without repeating the time zone name for each
abbreviation, use the following query:
SELECT UNIQUE tzname FROM V$TIMEZONE_NAMES;
For the default time zone file, this results in output similar to the following:
TZNAME
--------------------
Africa/Algiers
Africa/Cairo
Africa/Casablanca
Africa/Ceuta
...
US/Pacific
US/Pacific-New
US/Samoa
Time Zone Abbreviation Meaning
LMT Local Mean Time
PMT Paris Mean Time
WET Western European Time
WEST Western European Summer Time
CET Central Europe Time
CEST Central Europe Summer Time
EET Eastern Europe Time
EEST Eastern Europe Summer Time
Upgrading the Time Zone File
Datetime Datatypes and Time Zone Support 4-17
UTC
W-SU
WET
The default time zone file contains more than 350 unique time zone names. The small
time zone file contains more than 180 unique time zone names.
Upgrading the Time Zone File
The time zone files that are supplied with Oracle Database are updated periodically to
reflect changes in transition rules for various time zone regions. The files supplied
with Oracle Database 11g have been updated to version 3. This version includes the
recent change in the Daylight Savings Time (DST) rule for US time zones starting with
the year 2007.
DST Transition Rules Changes
The changes to DST transition rules may affect existing data of TIMESTAMP WITH
TIME ZONE datatype, because of the way Oracle Database stores this data internally.
When users enter timestamps with time zone, Oracle Database converts the data to
UTC, based on the transition rules in the time zone file, and stores the data together
with the ID of the original time zone on disk. When data is retrieved, the reverse
conversion from UTC takes place. For example, when the version 2 transition rules
were in effect, the value TIMESTAMP '2007-11-02 12:00:00 America/Los_
Angeles', would have been stored as UTC value '2007-11-02 20:00:00' plus
the time zone ID for 'America/Los_Angeles'. The time in Los Angeles would
have been UTC minus eight hours (PST). Under version 3 of the transition rules, the
offset for the same day is minus seven hours (PDT). Beginning with year 2007, the DST
will be in effect longer (until the first Sunday of November, which is November 4th in
year 2007). Now when users retrieve the same timestamp and the new offset is added
to the stored UTC time, they will receive TIMESTAMP '2007-11-02 13:00:00
America/Los_Angeles'. There is a one hour difference compared to the data
previous to version 3 taking effect.
In the most common case, the value TIMESTAMP '2007-11-02 12:00:00
America/Los_Angeles' is meant to represent noon of November 2nd, 2007 in Los
Angeles. Because the change to the DST transition rules introduces the one hour shift,
the timestamp must be updated to point back to 12:00 p.m., as described further in this
section. In the less common case, the value might be meant to represent the local time
in Los Angeles when it is 08:00 p.m. in UTC. In this less common case, the value
actually becomes correct only after the time zone file has been updated. No further
correction is needed in this case. Therefore, before updating any timestamp values, it is
important to understand what the values are meant to represent.
See Also:
■"Customizing Time Zone Data" on page 13-15
■"Time Zone Names" on page A-23 for a list of valid Oracle
Database time zone names
Note: Oracle Database 9i includes version 1 of the time zone files,
and Oracle Database 10g includes version 2. Various patches and
patch sets, which are released separately for these releases, may
update the time zone file version as well.
Upgrading the Time Zone File
4-18 Oracle Database Globalization Support Guide
Updating the Time Zone File with the utltzuv2.sql Script
You can use the $ORACLE_HOME/rdbms/admin/utltzuv2.sql script to discover
all columns of TIMESTAMP WITH TIME ZONE datatype in your database that are
potentially affected by a time zone file update. The result is stored in the sys.sys_
tzuv2_temptab table, which has five columns: table_owner, table_name,
column_name, rowcount, and nested_tab. Each row of sys.sys_tzuv2_
temptab describes a TIMESTAMP WITH TIME ZONE table column that: (a) contains at
least one timestamp in any of the time zone regions that are affected by the time zone
file update, or (b) belongs to a nested table. The nested_tab value 'YES' indicates
that the table specified in the table_name has been inserted because of condition (b).
For performance reasons, nested table columns are reported without scanning their
contents for the affected time zone regions. For columns inserted because of condition
(a), the rowcount value contains the number of timestamps in the column that
contains one of the affected time zone regions.
The utltzuv2.sql script must be run before you update the database time zone file.
This script identifies the time zone regions to search for by comparing the version of
the current database time zone file with the version of the time zone file for which the
script has been created. If the database time zone file is updated too early, then the
script does nothing, as the two versions are equal. If the time zone file changes as
result of an Oracle Database software upgrade from a previous release, or because a
patch set is installed, then the script must be run before the database is upgraded.
Therefore, before any new software is installed, you must locate and install the
appropriate utltzuv2.sql patch that is specifically for your combination of old
software version and new time zone file version.
To run the utltzuv2.sql script, start SQL*Plus, log in as SYSDBA, and run the
following command:
SQL> @?/rdbms/admin/utltzuv2.sql
If your database has data that will be affected by the time zone file update, as
discussed in the preceding section, then back up the timestamp data to an alternative
format before you upgrade the time zone file. After the upgrade, update the data using
the backup that you created, to ensure that the data is stored based on the new rules.
The following example illustrates the update process:
Example 4–5 Upgrading the Time Zone File and Correcting Affected Timestamp Data
Let's assume that the application data contains the following table with a TIMESTAMP
WITH TIME ZONE column.
Note: For any time zone region whose transition rules have been
updated, the issue discussed in this section, "Upgrading the Time
Zone File", affects only timestamps that point to the future relative to
the effective date of the corresponding DST rule change. For example,
no timestamp before year 2007 is affected by the version 3 change to
the 'America/Los_Angeles' time zone region.
See Also: For the matrix of available patches, visit the Oracle
MetaLink site at http://metalink.oracle.com, and see
Document ID 396906.1.
Upgrading the Time Zone File
Datetime Datatypes and Time Zone Support 4-19
CREATE TABLE tztab(x NUMBER PRIMARY KEY, y TIMESTAMP WITH TIME ZONE);
INSERT INTO tztab VALUES(1, TIMESTAMP '2007-11-02 12:00:00 America/Los_Angeles');
Before upgrading, create a table tztab_back in order to back up the timestamps from
column y in text format:
CREATE TABLE tztab_back(x NUMBER PRIMARY KEY, y VARCHAR2(256));
INSERT INTO tztab_back SELECT x, TO_CHAR(y, 'YYYY-MM-DD HH24.MI.SSXFF TZR') FROM
tztab;
To reduce the number of rows processed, you can add a WHERE clause and back up
only those timestamps that are affected by the relevant time zone region change. In
this example, the clause could be:
WHERE y > TIMESTAMP '2007-01-01 00:00:00 +00:00'
After upgrading, update the data in the table tztab using the value in tztab_back,
as follows:
UPDATE tztab t SET t.y =
(SELECT to_timestamp_tz(t1.y,'YYYY-MM-DD HH24.MI.SSXFF TZR')
FROM tztab_back t1
WHERE t.x = t1.x);
If you added the WHERE clause when populating tztab_back, then add the same
clause to the UPDATE statement as follows:
UPDATE tztab t SET t.y =
(SELECT to_timestamp_tz(t1.y,'YYYY-MM-DD HH24.MI.SSXFF TZR')
FROM tztab_back t1
WHERE t.x = t1.x)
WHERE t.y > TIMESTAMP '2007-01-01 00:00:00 +00:00'
Although the transition rule changes may affect data of TIMESTAMP WITH LOCAL
TIME ZONE datatype, there is no way to upgrade the data. The data cannot be
upgraded because this datatype does not preserve the original time zone/region
associated with the data.
Customers who update the time zone file in a database, and who use time zone
regions that are affected by the new file version, are required to update the time zone
file of all database clients. Additionally, all other databases communicating with this
database must be updated to the same version. This ensures that the whole database
environment will have the same version of the time zone file. This is not a requirement
for customers not using the affected regions. However, Oracle recommends that you
do so.
Note: The Export utility cannot be used to correct the timestamps,
because timestamps are exported in the internal storage format.
Export followed by Import never changes the values.
Note: You can find the matrix of available patches for updating your
time zone files by going to Oracle MetaLink at
http://metalink.oracle.com and reading Document ID
396906.1.
Upgrading the Time Zone File
4-20 Oracle Database Globalization Support Guide
The utltzuv2.sql script that was provided for Oracle Database 10g to update its
time zone file to version 3 uses an external table based on the supplied
timezdif.csv file to describe time zone changes introduced in the version of the
time zone file associated with the script and in the previous versions. To access this
data yourself, for example, to check the years in which a changed rule is valid, create
an equivalent external table as in the following example. Replace $ORACLE_HOME with
the actual path to the Oracle Home directory of your Oracle Database software
installation.
Example 4–6 Sample External Table to Query Contents of timezdif.csv
The following example creates an external table whose contents come from the file
$ORACLE_HOME/oracore/zoneinfo/timezdif.csv:
CONNECT / AS SYSDBA
CREATE DIRECTORY work_dir AS '$ORACLE_HOME/oracore/zoneinfo/';
GRANT READ ON DIRECTORY work_dir TO SCOTT;
CONNECT scott/tiger
CREATE TABLE TZONEDIFTAB (
VERSION NUMBER,
TIMEZONE_NAME VARCHAR2(64),
FROM_YEAR NUMBER,
TO_YEAR NUMBER
)
ORGANIZATION EXTERNAL
(TYPE oracle_loader
DEFAULT DIRECTORY work_dir
ACCESS PARAMETERS
(
RECORDS DELIMITED BY newline SKIP 3
FIELDS TERMINATED BY "," OPTIONALLY ENCLOSED BY "'"
(
VERSION CHAR(5),
TIMEZONE_NAME CHAR(64),
FROM_YEAR CHAR(5),
TO_YEAR CHAR(5)
)
)
LOCATION ('timezdif.csv')
)
REJECT LIMIT UNLIMITED;
SELECT * FROM TZONEDIFTAB;
VERSION TIMEZONE_NAME FROM_YEAR TO_YEAR
---------- ---------------------------------------- ---------- ----------
3 Asia/Hong_Kong 1998 null
3 Asia/Tehran 2024 2027
...
See Also: $ORACLE_
HOME/oracore/zoneinfo/timezdif.csv, provided with your
Oracle Database software installation, for a full list of time zones
changed since Oracle9i, and Oracle Database Upgrade Guide for
upgrade information
Setting the Session Time Zone
Datetime Datatypes and Time Zone Support 4-21
Setting the Database Time Zone
Set the database time zone when the database is created by using the SET TIME_ZONE
clause of the CREATE DATABASE statement. If you do not set the database time zone,
then it defaults to the time zone of the server's operating system.
The time zone may be set to an absolute offset from UTC or to a named region. To set
the time zone to an offset from UTC, use a statement similar to the following example:
CREATE DATABASE db01
...
SET TIME_ZONE='-05:00';
The range of valid offsets is -12:00 to +14:00.
To set the time zone to a named region, use a statement similar to the following
example:
CREATE DATABASE db01
...
SET TIME_ZONE='Europe/London';
You can change the database time zone by using the SET TIME_ZONE clause of the
ALTER DATABASE statement. For example:
ALTER DATABASE SET TIME_ZONE='05:00';
ALTER DATABASE SET TIME_ZONE='Europe/London';
The ALTER DATABASE SET TIME_ZONE statement returns an error if the database
contains a table with a TIMESTAMP WITH LOCAL TIME ZONE column and the
column contains data.
The change does not take effect until the database has been shut down and restarted.
You can find out the database time zone by entering the following query:
SELECT dbtimezone FROM DUAL;
Setting the Session Time Zone
You can set the default session time zone with the ORA_SDTZ environment variable.
When users retrieve TIMESTAMP WITH LOCAL TIME ZONE data, Oracle Database
returns it in the users' session time zone. The session time zone also takes effect when
a TIMESTAMP value is converted to the TIMESTAMP WITH TIME ZONE or
TIMESTAMP WITH LOCAL TIME ZONE datatype.
Note: The database time zone is relevant only for TIMESTAMP
WITH LOCAL TIME ZONE columns. Oracle recommends that you
set the database time zone to UTC (0:00) to avoid data conversion
and improve performance when data is transferred among
databases. This is especially important for distributed databases,
replication, and exporting and importing.
Converting Time Zones With the AT TIME ZONE Clause
4-22 Oracle Database Globalization Support Guide
The ORA_SDTZ environment variable can be set to the following values:
■Operating system local time zone ('OS_TZ')
■Database time zone ('DB_TZ')
■Absolute offset from UTC (for example, '-05:00')
■Time zone region name (for example, 'Europe/London')
To set ORA_SDTZ, use statements similar to one of the following in a UNIX
environment (C shell):
% setenv ORA_SDTZ 'OS_TZ'
% setenv ORA_SDTZ 'DB_TZ'
% setenv ORA_SDTZ '-05:00'
% setenv ORA_SDTZ 'Europe/London'
You can change the time zone for a specific SQL session with the SET TIME_ZONE
clause of the ALTER SESSION statement.
TIME_ZONE can be set to the following values:
■Default local time zone when the session was started (local)
■Database time zone (dbtimezone)
■Absolute offset from UTC (for example, '+10:00')
■Time zone region name (for example, 'Asia/Hong_Kong')
Use ALTER SESSION statements similar to the following:
ALTER SESSION SET TIME_ZONE=local;
ALTER SESSION SET TIME_ZONE=dbtimezone;
ALTER SESSION SET TIME_ZONE='+10:00';
ALTER SESSION SET TIME_ZONE='Asia/Hong_Kong';
You can find out the current session time zone by entering the following query:
SELECT sessiontimezone FROM DUAL;
Converting Time Zones With the AT TIME ZONE Clause
A datetime SQL expression can be one of the following:
■A datetime column
■A compound expression that yields a datetime value
A datetime expression can include an AT LOCAL clause or an AT TIME ZONE clause.
If you include an AT LOCAL clause, then the result is returned in the current session
time zone. If you include the AT TIME ZONE clause, then use one of the following
settings with the clause:
Note: Setting the session time zone does not affect the value
returned by the SYSDATE and SYSTIMESTAMP SQL function.
SYSDATE returns the date and time of the operating system on
which the database resides, taking into account the time zone of the
database server's operating system that was in effect when the
database was started.
Support for Daylight Saving Time
Datetime Datatypes and Time Zone Support 4-23
■Time zone offset: The string '(+|-)HH:MM' specifies a time zone as an offset from
UTC. For example, '-07:00' specifies the time zone that is 7 hours behind UTC.
For example, if the UTC time is 11:00 a.m., then the time in the '-07:00' time
zone is 4:00 a.m.
■DBTIMEZONE: Oracle Database uses the database time zone established (explicitly
or by default) during database creation.
■SESSIONTIMEZONE: Oracle Database uses the session time zone established by
default or in the most recent ALTER SESSION statement.
■Time zone region name: Oracle Database returns the value in the time zone
indicated by the time zone region name. For example, you can specify
Asia/Hong_Kong.
■An expression: If an expression returns a character string with a valid time zone
format, then Oracle Database returns the input in that time zone. Otherwise,
Oracle Database returns an error.
The following example converts the datetime value in the America/New_York time
zone to the datetime value in the America/Los_Angeles time zone.
Example 4–7 Converting a Datetime Value to Another Time Zone
SELECT FROM_TZ(CAST(TO_DATE('1999-12-01 11:00:00',
'YYYY-MM-DD HH:MI:SS') AS TIMESTAMP), 'America/New_York')
AT TIME ZONE 'America/Los_Angeles' "West Coast Time"
FROM DUAL;
West Coast Time
----------------------------------------------------------
01-DEC-99 08.00.00.000000 AM AMERICA/LOS_ANGELES
Support for Daylight Saving Time
Oracle Database automatically determines whether Daylight Saving Time is in effect
for a specified time zone and returns the corresponding local time. The datetime value
is usually sufficient for Oracle Database to determine whether Daylight Saving Time is
in effect for a specified time zone. The periods when Daylight Saving Time begins or
ends are boundary cases. For example, in the Eastern region of the United States, the
time changes from 01:59:59 a.m. to 3:00:00 a.m. when Daylight Saving Time goes into
effect. The interval between 02:00:00 and 02:59:59 a.m. does not exist. Values in that
interval are invalid. When Daylight Saving Time ends, the time changes from 02:00:00
a.m. to 01:00:01 a.m. The interval between 01:00:01 and 02:00:00 a.m. is repeated.
Values from that interval are ambiguous because they occur twice.
To resolve these boundary cases, Oracle Database uses the TZR and TZD format
elements. TZR represents the time zone region in datetime input strings. Examples are
'Australia/North', 'UTC', and 'Singapore'. TZD represents an abbreviated form of
the time zone region with Daylight Saving Time information. Examples are 'PST' for
US/Pacific standard time and 'PDT' for US/Pacific daylight time. To see a list of valid
values for the TZR and TZD format elements, query the TZNAME and TZABBREV
columns of the V$TIMEZONE_NAMES dynamic performance view.
See Also: Oracle Database SQL Reference
See Also: "Time Zone Names" on page A-23 for a list of valid time
zones
Support for Daylight Saving Time
4-24 Oracle Database Globalization Support Guide
Examples: The Effect of Daylight Saving Time on Datetime Calculations
The TIMESTAMP datatype does not accept time zone values and does not calculate
Daylight Saving Time.
The TIMESTAMP WITH TIME ZONE and TIMESTAMP WITH LOCAL TIME ZONE
datatypes have the following behavior:
■If a time zone region is associated with the datetime value, then the database
server knows the Daylight Saving Time rules for the region and uses the rules in
calculations.
■Daylight Saving Time is not calculated for regions that do not use Daylight Saving
Time.
The rest of this section contains examples that use datetime datatypes. The examples
use the global_orders table. It contains the orderdate1 column of TIMESTAMP
datatype and the orderdate2 column of TIMESTAMP WITH TIME ZONE datatype.
The global_orders table is created as follows:
CREATE TABLE global_orders ( orderdate1 TIMESTAMP(0),
orderdate2 TIMESTAMP(0) WITH TIME ZONE);
INSERT INTO global_orders VALUES ( '28-OCT-00 11:24:54 PM',
'28-OCT-00 11:24:54 PM America/New_York');
Example 4–8 Comparing Daylight Saving Time Calculations Using TIMESTAMP WITH
TIME ZONE and TIMESTAMP
SELECT orderdate1 + INTERVAL '8' HOUR, orderdate2 + INTERVAL '8' HOUR
FROM global_orders;
The following output results:
ORDERDATE1+INTERVAL'8'HOUR ORDERDATE2+INTERVAL'8'HOUR
-------------------------- --------------------------
29-OCT-00 07.24.54.000000 AM 29-OCT-00 06.24.54.000000 AM AMERICA/NEW_YORK
This example shows the effect of adding 8 hours to the columns. The time period
includes a Daylight Saving Time boundary (a change from Daylight Saving Time to
standard time). The orderdate1 column is of TIMESTAMP datatype, which does not
use Daylight Saving Time information and thus does not adjust for the change that
took place in the 8-hour interval. The TIMESTAMP WITH TIME ZONE datatype does
adjust for the change, so the orderdate2 column shows the time as one hour earlier
than the time shown in the orderdate1 column.
Example 4–9 Comparing Daylight Saving Time Calculations Using TIMESTAMP WITH
LOCAL TIME ZONE and TIMESTAMP
The TIMESTAMP WITH LOCAL TIME ZONE datatype uses the value of TIME_ZONE
that is set for the session environment. The following statements set the value of the
TIME_ZONE session parameter and create a global_orders table. The global_
orders table has one column of TIMESTAMP datatype and one column of TIMESTAMP
WITH LOCAL TIME ZONE datatype.
ALTER SESSION SET TIME_ZONE='America/New_York';
CREATE TABLE global_orders ( orderdate1 TIMESTAMP(0),
Note: If you have created a global_orders table for the
previous examples, then drop the global_orders table before
you try Example 4–9 through Example 4–10.
Support for Daylight Saving Time
Datetime Datatypes and Time Zone Support 4-25
orderdate2 TIMESTAMP(0) WITH LOCAL TIME ZONE );
INSERT INTO global_orders VALUES ( '28-OCT-00 11:24:54 PM',
'28-OCT-00 11:24:54 PM' );
Add 8 hours to both columns.
SELECT orderdate1 + INTERVAL '8' HOUR, orderdate2 + INTERVAL '8' HOUR
FROM global_orders;
Because a time zone region is associated with the datetime value for orderdate2, the
Oracle Database server uses the Daylight Saving Time rules for the region. Thus the
output is the same as in Example 4–8. There is a one-hour difference between the two
calculations because Daylight Saving Time is not calculated for the TIMESTAMP
datatype, and the calculation crosses a Daylight Saving Time boundary.
Example 4–10 Daylight Saving Time Is Not Calculated for Regions That Do Not Use
Daylight Saving Time
Set the time zone region to UTC. UTC does not use Daylight Saving Time.
ALTER SESSION SET TIME_ZONE='UTC';
Truncate the global_orders table.
TRUNCATE TABLE global_orders;
Insert values into the global_orders table.
INSERT INTO global_orders VALUES ( '28-OCT-00 11:24:54 PM',
TIMESTAMP '2000-10-28 23:24:54 ' );
Add 8 hours to the columns.
SELECT orderdate1 + INTERVAL '8' HOUR, orderdate2 + INTERVAL '8' HOUR
FROM global_orders;
The following output results.
ORDERDATE1+INTERVAL'8'HOUR ORDERDATE2+INTERVAL'8'HOUR
-------------------------- ---------------------------
29-OCT-00 07.24.54.000000000 AM 29-OCT-00 07.24.54.000000000 AM UTC
The times are the same because Daylight Saving Time is not calculated for the UTC
time zone region.
Support for Daylight Saving Time
4-26 Oracle Database Globalization Support Guide
Linguistic Sorting and String Searching 5-1
5
Linguistic Sorting and String Searching
This chapter explains linguistic sorting and searching for strings in an Oracle Database
environment.
This chapter contains the following topics:
■Overview of Oracle Database Sorting Capabilities
■Using Binary Sorts
■Using Linguistic Sorts
■Linguistic Sort Features
■Case-Insensitive and Accent-Insensitive Linguistic Sorts
■Performing Linguistic Comparisons
■Using Linguistic Indexes
■Searching Linguistic Strings
■SQL Regular Expressions in a Multilingual Environment
Overview of Oracle Database Sorting Capabilities
Different languages have different sort orders. In addition, different cultures or
countries that use the same alphabets may sort words differently. For example, in
Danish, Æ is after Z, while Y and Ü are considered to be variants of the same letter.
Sort order can be case-sensitive or case-insensitive. Case refers to the condition of
being uppercase or lowercase. For example, in a Latin alphabet, A is the uppercase
glyph for a, the lowercase glyph.
Sort order can ignore or consider diacritics. A diacritic is a mark near or through a
character or combination of characters that indicates a different sound than the sound
of the character without the diacritic. For example, the cedilla (,) in façade is a
diacritic. It changes the sound of c.
Sort order can be phonetic or it can be based on the appearance of the character. For
example, sort order can be based on the number of strokes in East Asian ideographs.
Another common sorting issue is combining letters into a single character. For
example, in traditional Spanish, ch is a distinct character that comes after c, which
means that the correct order is: cerveza, colorado, cheremoya. This means that the
letter c cannot be sorted until Oracle Database has checked whether the next letter is
an h.
Oracle Database provides the following types of sorts:
■Binary sort
Using Binary Sorts
5-2 Oracle Database Globalization Support Guide
■Monolingual linguistic sort
■Multilingual linguistic sort
These sorts achieve a linguistically correct order for a single language as well as a sort
based on the multilingual ISO standard (ISO 14651), which is designed to handle many
languages at the same time.
Using Binary Sorts
One way to sort character data is based on the numeric values of the characters
defined by the character encoding scheme. This is called a binary sort. Binary sorts are
the fastest type of sort. They produce reasonable results for the English alphabet
because the ASCII and EBCDIC standards define the letters A to Z in ascending
numeric value.
When characters used in other languages are present, a binary sort usually does not
produce reasonable results. For example, an ascending ORDER BY query returns the
character strings ABC, ABZ, BCD, ÄBC, when Ä has a higher numeric value than B in the
character encoding scheme. A binary sort is not usually linguistically meaningful for
Asian languages that use ideographic characters.
Using Linguistic Sorts
To produce a sort sequence that matches the alphabetic sequence of characters, another
sort technique must be used that sorts characters independently of their numeric
values in the character encoding scheme. This technique is called a linguistic sort. A
linguistic sort operates by replacing characters with numeric values that reflect each
character's proper linguistic order.
Oracle Database offers two kinds of linguistic sorts: monolingual and multilingual.
This section includes the following topics:
■Monolingual Linguistic Sorts
■Multilingual Linguistic Sorts
■Multilingual Sorting Levels
■Linguistic Sort Examples
Monolingual Linguistic Sorts
Oracle Database compares character strings in two steps for monolingual sorts. The
first step compares the major value of the entire string from a table of major values.
Usually, letters with the same appearance have the same major value. The second step
compares the minor value from a table of minor values. The major and minor values
are defined by Oracle Database. Oracle Database defines letters with diacritic and case
differences as having the same major value but different minor values.
Each major table entry contains the Unicode code point and major value for a
character. The Unicode code point is a 16-bit binary value that represents a character.
Note: In the ASCII standard, all uppercase letters appear before
any lowercase letters. In the EBCDIC standard, the opposite is true:
all lowercase letters appear before any uppercase letters.
Using Linguistic Sorts
Linguistic Sorting and String Searching 5-3
Table 5–1 illustrates sample values for sorting a, A, ä, Ä, and b.
Multilingual Linguistic Sorts
Oracle Database provides multilingual linguistic sorts so that you can sort data in
more than one language in one sort. This is useful for regions or languages that have
complex sorting rules and for multilingual databases. As of Oracle Database 11g,
Oracle Database supports all of the sort orders defined by previous releases.
For Asian language data or multilingual data, Oracle Database provides a sorting
mechanism based on the ISO 14651 standard and the Unicode 5.0 standard. Chinese
characters are ordered by the number of strokes, PinYin, or radicals.
In addition, multilingual sorts can handle canonical equivalence and supplementary
characters. Canonical equivalence is a basic equivalence between characters or
sequences of characters. For example, ç is equivalent to the combination of c and ,.
Supplementary characters are user-defined characters or predefined characters in
Unicode that require two code points within a specific code range. You can define up
to 1.1 million code points in one multilingual sort.
For example, Oracle Database supports a monolingual French sort (FRENCH), but you
can specify a multilingual French sort (FRENCH_M). _M represents the ISO 14651
standard for multilingual sorting. The sorting order is based on the GENERIC_M
sorting order and can sort diacritical marks from right to left. Oracle recommends
using a multilingual linguistic sort if the tables contain multilingual data. If the tables
contain only French, then a monolingual French sort may have better performance
because it uses less memory. It uses less memory because fewer characters are defined
in a monolingual French sort than in a multilingual French sort. There is a tradeoff
between the scope and the performance of a sort.
Table 5–1 Sample Glyphs and Their Major and Minor Sort Values
Glyph Major Value Minor Value
a15 5
A15 10
ä15 15
Ä15 20
b20 5
Note: Monolingual linguistic sorting is not available for
non-Unicode multibyte database character sets. If a monolingual
linguistic sort is specified when the database character set is
non-Unicode multibyte, then the default sort order is the binary sort
order of the database character set. One exception is UNICODE_
BINARY. This sort is available for all character sets.
See Also: "Overview of Unicode" on page 6-1
See Also:
■"Canonical Equivalence" on page 5-7
■"Supplementary Characters" on page 6-2
Using Linguistic Sorts
5-4 Oracle Database Globalization Support Guide
Multilingual Sorting Levels
Oracle Database evaluates multilingual sorts at three levels of precision:
■Primary Level Sorts
■Secondary Level Sorts
■Tertiary Level Sorts
Primary Level Sorts
A primary level sort distinguishes between base letters, such as the difference
between characters a and b. It is up to individual locales to define whether a is before
b, b is before a, or if they are equal. The binary representation of the characters is
completely irrelevant. If a character is an ignorable character, then it is assigned a
primary level order (or weight) of zero, which means it is ignored at the primary level.
Characters that are ignorable on other levels are given an order of zero at those levels.
For example, at the primary level, all variations of bat come before all variations of
bet. The variations of bat can appear in any order, and the variations of bet can
appear in any order:
Bat
bat
BAT
BET
Bet
bet
Secondary Level Sorts
A secondary level sort distinguishes between base letters (the primary level sort)
before distinguishing between diacritics on a given base letter. For example, the
character Ä differs from the character A only because it has a diacritic. Thus, Ä and A
are the same on the primary level because they have the same base letter (A) but differ
on the secondary level.
The following list has been sorted on the primary level (resume comes before
resumes) and on the secondary level (strings without diacritics come before strings
with diacritics):
resume
résumé
Résumé
Resumes
resumes
résumés
Tertiary Level Sorts
A tertiary level sort distinguishes between base letters (primary level sort), diacritics
(secondary level sort), and case (upper case and lower case). It can also include special
characters such as +, -, and *.
The following are examples of tertiary level sorts:
■Characters a and A are equal on the primary and secondary levels but different on
the tertiary level because they have different cases.
See Also: "Ignorable Characters" on page 5-6
Linguistic Sort Features
Linguistic Sorting and String Searching 5-5
■Characters ä and A are equal on the primary level and different on the secondary
and tertiary levels.
■The primary and secondary level orders for the dash character - is 0. That is, it is
ignored on the primary and secondary levels. If a dash is compared with another
character whose primary level order is nonzero, for example, u, then no result for
the primary level is available because u is not compared with anything. In this
case, Oracle Database finds a difference between - and u only at the tertiary level.
The following list has been sorted on the primary level (resume comes before
resumes) and on the secondary level (strings without diacritics come before strings
with diacritics) and on the tertiary level (lower case comes before upper case):
resume
Resume
résumé
Résumé
resumes
Resumes
résumés
Résumés
Linguistic Sort Features
This section contains information about different features that a linguistic sort can
have:
■Base Letters
■Ignorable Characters
■Contracting Characters
■Expanding Characters
■Context-Sensitive Characters
■Canonical Equivalence
■Reverse Secondary Sorting
■Character Rearrangement for Thai and Laotian Characters
■Special Letters
■Special Combination Letters
■Special Uppercase Letters
■Special Lowercase Letters
You can customize linguistic sorts to include the desired characteristics.
Base Letters
Base letters are defined in a base letter table, which maps each letter to its base letter.
For example, a, A, ä, and Ä all map to a, which is the base letter. This concept is
particularly relevant for working with Oracle Text.
See Also: Chapter 13, "Customizing Locale Data"
See Also: Oracle Text Reference
Linguistic Sort Features
5-6 Oracle Database Globalization Support Guide
Ignorable Characters
Some characters can be ignored in a linguistic sort. These characters are called
ignorable characters. There are two kinds of ignorable characters: diacritics and
punctuation.
Examples of ignorable diacritics are:
■^, so that rôle is treated the same as role
■The umlaut, so that naïve is treated the same as naive
An example of an ignorable punctuation character is the dash character -. If it is
ignored, then multi-lingual can be treated that same as multilingual and
e-mail can be treated the same as email.
Contracting Characters
Sorting elements usually consist of a single character, but in some locales, two or more
characters in a character string must be considered as a single sorting element during
sorting. For example, in traditional Spanish, the string ch is composed of two
characters. These characters are called contracting characters in multilingual linguistic
sorting and special combination letters in monolingual linguistic sorting.
Do not confuse a composed character with a contracting character. A composed
character like á can be decomposed into a and ', each with their own encoding. The
difference between a composed character and a contracting character is that a
composed character can be displayed as a single character on a terminal, while a
contracting character is used only for sorting, and its component characters must be
rendered separately.
Expanding Characters
In some locales, certain characters must be sorted as if they were character strings. An
example is the German character ß (sharp s). It is sorted exactly the same as the string
SS. Another example is that ö sorts as if it were oe, after od and before of. These
characters are known as expanding characters in multilingual linguistic sorting and
special letters in monolingual linguistic sorting. Just as with contracting characters,
the replacement string for an expanding character is meaningful only for sorting.
Context-Sensitive Characters
In Japanese, a prolonged sound mark that resembles an em dash — represents a length
mark that lengthens the vowel of the preceding character. The sort order depends on
the vowel that precedes the length mark. This is called context-sensitive sorting. For
example, after the character ka, the — length mark indicates a long a and is treated the
same as a, while after the character ki, the — length mark indicates a long i and is
treated the same as i. Transliterating this to Latin characters, a sort might look like
this:
kaa
ka— -- kaa and ka— are the same
kai -- kai follows ka- because i is after a
kia -- kia follows kai because i is after a
kii -- kii follows kia because i is after a
ki— -- kii and ki— are the same
Linguistic Sort Features
Linguistic Sorting and String Searching 5-7
Canonical Equivalence
Canonical equivalence is an attribute of a multilingual sort and describes how
equivalent code point sequences are sorted. If canonical equivalence is applied in a
particular linguistic sort, then canonically equivalent strings are treated as equal.
One Unicode code point can be equivalent to a sequence of base letter code points plus
diacritic code points. This is called the Unicode canonical equivalence. For example, ä
equals its base letter a and an umlaut. A linguistic flag, CANONICAL_EQUIVALENCE =
TRUE, indicates that all canonical equivalence rules defined in Unicode need to be
applied in a specific linguistic sort. Oracle Database-defined linguistic sorts include the
appropriate setting for the canonical equivalence flag. You can set the flag to FALSE to
speed up the comparison and ordering functions if all the data is in its composed form.
For example, consider the following strings:
■äa (a umlaut followed by a)
■a¨b (a followed by umlaut followed by b)
■äc (a umlaut followed by c)
If CANONICAL_EQUIVALENCE=FALSE, then the sort order of the strings is:
a¨b
äa
äc
This occurs because a comes before ä if canonical equivalence is not applied.
If CANONICAL_EQUIVALENCE=TRUE, then the sort order of the strings is:
äa
a¨b
äc
This occurs because ä and a¨ are treated as canonically equivalent.
You can use Oracle Locale Builder to view the setting of the canonical equivalence flag
in existing multilingual sorts. When you create a customized multilingual sort with
Oracle Locale Builder, you can set the canonical equivalence flag as desired.
Reverse Secondary Sorting
In French, sorting strings of characters with diacritics first compares base letters from
left to right, but compares characters with diacritics from right to left. For example, by
default, a character with a diacritic is placed after its unmarked variant. Thus Èdit
comes before Edít in a French sort. They are equal on the primary level, and the
secondary order is determined by examining characters with diacritics from right to
left. Individual locales can request that the characters with diacritics be sorted with the
right-to-left rule. Set the REVERSE_SECONDARY linguistic flag to TRUE to enable
reverse secondary sorting.
See Also: "Creating a New Linguistic Sort with the Oracle Locale
Builder" on page 13-26 for more information about setting the
canonical equivalence flag
See Also: "Creating a New Linguistic Sort with the Oracle Locale
Builder" on page 13-26 for more information about setting the
reverse secondary flag
Linguistic Sort Features
5-8 Oracle Database Globalization Support Guide
Character Rearrangement for Thai and Laotian Characters
In Thai and Lao, some characters must first change places with the following character
before sorting. Normally, these types of characters are symbols representing vowel
sounds, and the next character is a consonant. Consonants and vowels must change
places before sorting. Set the SWAP_WITH_NEXT linguistic flag for all characters that
must change places before sorting.
Special Letters
Special letters is a term used in monolingual sorts. They are called expanding
characters in multilingual sorts.
Special Combination Letters
Special combination letters is the term used in monolingual sorts. They are called
contracting letters in multilingual sorts.
Special Uppercase Letters
One lowercase letter may map to multiple uppercase letters. For example, in
traditional German, the uppercase letters for ß are SS.
These case conversions are handled by the NLS_UPPER, NLS_LOWER, and NLS_
INITCAP SQL functions, according to the conventions established by the linguistic
sort sequence. The UPPER, LOWER, and INITCAP SQL functions cannot handle these
special characters, because their casing operation is based on binary mapping defined
for the underlying character set, which is not linguistic sensitive.
The NLS_UPPER SQL function returns all uppercase characters from the same
character set as the lowercase string. The following example shows the result of the
NLS_UPPER function when NLS_SORT is set to XGERMAN:
SELECT NLS_UPPER ('große') "Uppercase" FROM DUAL;
Upper
-----
GROSSE
Special Lowercase Letters
Oracle Database supports special lowercase letters. One uppercase letter may map to
multiple lowercase letters. An example is the Turkish uppercase I becoming a small,
dotless i.
See Also: "Creating a New Linguistic Sort with the Oracle Locale
Builder" on page 13-26 for more information about setting the
SWAP_WITH_NEXT flag
See Also: "Expanding Characters" on page 5-6
See Also: "Contracting Characters" on page 5-6
See Also: Oracle Database SQL Reference
Case-Insensitive and Accent-Insensitive Linguistic Sorts
Linguistic Sorting and String Searching 5-9
Case-Insensitive and Accent-Insensitive Linguistic Sorts
Operation inside an Oracle database is always sensitive to the case and the accents
(diacritics) of the characters. Sometimes you may need to perform case-insensitive or
accent-insensitive comparisons and sorts.
In previous versions of the database, case-insensitive queries could be achieved by
using the NLS_UPPER and NLS_LOWER SQL functions. The functions change the case
of strings based on a specific linguistic sort definition. This enables you to perform
case-insensitive searches regardless of the language being used. For example, create a
table called test1 as follows:
SQL> CREATE TABLE test1(word VARCHAR2(12));
SQL> INSERT INTO test1 VALUES('GROSSE');
SQL> INSERT INTO test1 VALUES('Große');
SQL> INSERT INTO test1 VALUES('große');
SQL> SELECT * FROM test1;
WORD
------------
GROSSE
Große
große
Perform a case-sensitive search for GROSSE as follows:
SQL> SELECT word FROM test1 WHERE word='GROSSE';
WORD
------------
GROSSE
Perform a case-insensitive search for GROSSE using the NLS_UPPER function:
SELECT word FROM test1
WHERE NLS_UPPER(word, 'NLS_SORT = XGERMAN') = 'GROSSE';
WORD
------------
GROSSE
Große
große
As of Oracle Database 10g, Oracle Database provides case-insensitive and
accent-insensitive options for linguistic sorts. Oracle Database provides the following
types of monolingual and multilingual linguistic sorts:
■Linguistic sorts that use information about base letters, diacritics, punctuation, and
case. These are the standard monolingual and multilingual linguistic sorts that are
described in "Using Linguistic Sorts" on page 5-2.
■Linguistic sorts that use information about base letters, diacritics, and punctuation.
This type of sort is called case-insensitive.
■Linguistic sorts that use information about base letters only. This type of sort is
called accent-insensitive. (Accent is another word for diacritic.) An
accent-insensitive sort is always case-insensitive as well.
The rest of this section contains the following topics:
■Examples of Case-Insensitive and Accent-Insensitive Sorts
■Specifying a Case-Insensitive or Accent-Insensitive Sort
Case-Insensitive and Accent-Insensitive Linguistic Sorts
5-10 Oracle Database Globalization Support Guide
Examples of Case-Insensitive and Accent-Insensitive Sorts
The following examples show:
■A sort that uses information about base letters, diacritics, punctuation, and case
■A case-insensitive sort
■An accent-insensitive sort
Example 5–1 Linguistic Sort Using Base Letters, Diacritics, Punctuation, and Case
Information
The following list has been sorted using information about base letters, diacritics,
punctuation, and case:
blackbird
black bird
black-bird
Blackbird
Black-bird
blackbîrd
bläckbird
Example 5–2 Case-Insensitive Linguistic Sort
The following list has been sorted using information about base letters, diacritics, and
punctuation, ignoring case:
black bird
black-bird
Black-bird
blackbird
Blackbird
blackbîrd
bläckbird
black-bird and Black-bird have the same value in the sort, because the only
different between them is case. They could appear interchanged in the list.
Blackbird and blackbird also have the same value in the sort and could appear
interchanged in the list.
Example 5–3 Accent-Insensitive Linguistic Sort
The following list has been sorted using information about base letters only. No
information about diacritics, punctuation, or case has been used.
blackbird
bläckbird
blackbîrd
Blackbird
BlackBird
Black-bird
Black bird
See Also:
■"NLS_SORT" on page 3-29
■"NLS_COMP" on page 3-30
Case-Insensitive and Accent-Insensitive Linguistic Sorts
Linguistic Sorting and String Searching 5-11
Specifying a Case-Insensitive or Accent-Insensitive Sort
Use the NLS_SORT session parameter to specify a case-insensitive or accent-insensitive
sort:
■Append _CI to an Oracle Database sort name for a case-insensitive sort.
■Append _AI to an Oracle Database sort name for an accent-insensitive and
case-insensitive sort.
For example, you can set NLS_SORT to the following types of values:
FRENCH_M_AI
XGERMAN_CI
Binary sorts can also be case-insensitive or accent-insensitive. When you specify
BINARY_CI as a value for NLS_SORT, it designates a sort that is accent-sensitive and
case-insensitive. BINARY_AI designates an accent-insensitive and case-insensitive
binary sort. You may want to use a binary sort if the binary sort order of the character
set is appropriate for the character set you are using.
For example, with the NLS_LANG environment variable set to AMERICAN_
AMERICA.WE8ISO8859P1, create a table called test2 and populate it as follows:
SQL> CREATE TABLE test2 (letter VARCHAR2(10));
SQL> INSERT INTO test2 VALUES('ä');
SQL> INSERT INTO test2 VALUES('a');
SQL> INSERT INTO test2 VALUES('A');
SQL> INSERT INTO test2 VALUES('Z');
SQL> SELECT * FROM test2;
LETTER
-----------
ä
a
A
Z
The default value of NLS_SORT is BINARY. Use the following statement to do a binary
sort of the characters in table test2:
SELECT * FROM test2 ORDER BY letter;
To change the value of NLS_SORT, enter a statement similar to the following:
ALTER SESSION SET NLS_SORT=BINARY_CI;
The following table shows the sort orders that result from setting NLS_SORT to
BINARY, BINARY_CI, and BINARY_AI.
When NLS_SORT=BINARY, uppercase letters come before lowercase letters. Letters
with diacritics appear last.
BINARY BINARY_CI BINARY_AI
Aaä
ZAa
aZA
ääZ
Case-Insensitive and Accent-Insensitive Linguistic Sorts
5-12 Oracle Database Globalization Support Guide
When the sort considers diacritics but ignores case (BINARY_CI), the letters with
diacritics appear last.
When both case and diacritics are ignored (BINARY_AI), ä is sorted with the other
characters whose base letter is a. All the characters whose base letter is a occur before
z.
You can use binary sorts for better performance when the character set is US7ASCII or
another character set that has the same sort order as the binary sorts.
The following table shows the sort orders that result from German sorts for the table.
A German sort places lowercase letters before uppercase letters, and ä occurs before Z.
When the sort ignores both case and diacritics (GERMAN_AI), ä appears with the other
characters whose base letter is a.
Linguistic Sort Examples
The examples in this section demonstrate a binary sort, a monolingual sort, and a
multilingual sort. To prepare for the examples, create and populate a table called
test3. Enter the following statements:
SQL> CREATE TABLE test3 (name VARCHAR2(20));
SQL> INSERT INTO test3 VALUES('Diet');
SQL> INSERT INTO test3 VALUES('À voir');
SQL> INSERT INTO test3 VALUES('Freizeit');
Example 5–4 Binary Sort
The ORDER BY clause uses a binary sort.
SQL> SELECT * FROM test3 ORDER BY name;
You should see the following output:
Diet
Freizeit
À voir
Note that a binary sort results in À voir being at the end of the list.
Example 5–5 Monolingual German Sort
Use the NLSSORT function with the NLS_SORT parameter set to german to obtain a
German sort.
SQL> SELECT * FROM test3 ORDER BY NLSSORT(name, 'NLS_SORT=german');
You should see the following output:
À voir
Diet
Freizeit
GERMAN GERMAN_CI GERMAN_AI
aaä
AAa
ääA
ZZZ
Performing Linguistic Comparisons
Linguistic Sorting and String Searching 5-13
Note that À voir is at the beginning of the list in a German sort.
Example 5–6 Comparing a Monolingual German Sort to a Multilingual Sort
Insert the character string shown in Figure 5–1 into test. It is a D with a crossbar
followed by ñ.
Figure 5–1 Character String
Perform a monolingual German sort by using the NLSSORT function with the NLS_
SORT parameter set to german.
SQL> SELECT * FROM test2 ORDER BY NLSSORT(name, 'NLS_SORT=german');
The output from the German sort shows the new character string last in the list of
entries because the characters are not recognized in a German sort.
Perform a multilingual sort by entering the following statement:
SQL> SELECT * FROM test2 ORDER BY NLSSORT(name, 'NLS_SORT=generic_m');
The output shows the new character string after Diet, following ISO sorting rules.
Performing Linguistic Comparisons
When performing SQL comparison operations, characters are compared according to
their binary values. A character is greater than another if it has a higher binary value.
Because the binary sequences rarely match the linguistic sequences for most
languages, such comparisons may not be meaningful for a typical user. To achieve a
meaningful comparison, you can specify behavior by using the session parameters
NLS_COMP and NLS_SORT. The way you set these two parameters determines the
rules by which characters are sorted and compared.
The NLS_COMP setting determines how NLS_SORT is handled by the SQL operations.
There are three valid values for NLS_COMP:
■BINARY
All SQL sorts and comparisons are based on the binary values of the string
characters, regardless of the value set to NLS_SORT. This is the default setting.
■LINGUISTIC
All SQL sorting and comparison are based on the linguistic rule specified by NLS_
SORT. For example, NLS_COMP=LINGUISTIC and NLS_SORT=BINARY_CI means
the collation sensitive SQL operations will use binary value for sorting and
comparison but ignore character case.
■ANSI
See Also:
■"The NLSSORT Function" on page 9-7
■"NLS_SORT" on page 3-29 for more information about setting
and changing the NLS_SORT parameter
Performing Linguistic Comparisons
5-14 Oracle Database Globalization Support Guide
A limited set of SQL functions honor the NLS_SORT setting. ANSI is available for
backward compatibility only. In general, you should set NLS_COMP to
LINGUISTIC when performing linguistic comparison.
Table 5–2 shows how different SQL operations behave with these different settings.
Table 5–2 Linguistic Comparison Behavior with NLS_COMP Settings
BINARY LINGUISTIC ANSI
SQL Operators
UNION, INTERSECT, MINUS Binary Honors NLS_SORT Binary
SQL Functions
DECODE Binary Honors NLS_SORT Binary
INSTRx Binary Honors NLS_SORT Binary
LEAST, GREATEST Binary Honors NLS_SORT Binary
MAX, MIN Binary Honors NLS_SORT Binary
NLS_INITCAP Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
NLS_LOWER Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
NLS_UPPER Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
NLSSORT Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
NULLIF Binary Honors NLS_SORT Binary
REGEXP_COUNT Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
REGEXP_INSTR Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
REGEXP_LIKE Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
REGEXP_REPLACE Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
REGEXP_SUBSTR Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
REPLACE Binary Honors NLS_SORT Binary
RTRIM, TRIM, LTRIM Binary Honors NLS_SORT Binary
TRANSLATE, TRANSLATE USING Binary Honors NLS_SORT Binary
SQL Expressions
=, !=, >, <, >=, <= Binary Honors NLS_SORT Honors NLS_SORT
BETWEEN, NOT BETWEEN Binary Honors NLS_SORT Honors NLS_SORT
CASE Binary Honors NLS_SORT Binary
DISTINCT Binary Honors NLS_SORT Binary
GROUP Binary Honors NLS_SORT Binary
GROUP BY Binary Honors NLS_SORT Binary
HAVING Binary Honors NLS_SORT Honors NLS_SORT
IN, NOT IN Binary Honors NLS_SORT Honors NLS_SORT
LIKE Binary Honors NLS_SORT Binary
ORDER BY Honors NLS_SORT Honors NLS_SORT Honors NLS_SORT
START WITH Binary Honors NLS_SORT Honors NLS_SORT
UNIQUE Binary Honors NLS_SORT Binary
Performing Linguistic Comparisons
Linguistic Sorting and String Searching 5-15
See "NLS_COMP" and "NLS_SORT" for information regarding these parameters.
Linguistic Comparison Examples
The following examples illustrate behavior with different NLS_COMP settings.
Example 5–7 Binary Comparison Binary Sort
The following illustrates behavior with a binary setting:
SQL> ALTER SESSION SET NLS_COMP=BINARY;
SQL> ALTER SESSION SET NLS_SORT=BINARY;
SQL> SELECT ename FROM emp1;
ENAME
----------------------
Mc Calla
MCAfee
McCoye
Mccathye
McCafeé
5 rows selected
SQL> SELECT ename FROM emp1 WHERE ename LIKE 'McC%e';
ENAME
----------------------
McCoye
1 row selected
Example 5–8 Linguistic Comparison Binary Case-Insensitive Sort
The following illustrates behavior with a case-insensitive setting:
SQL> ALTER SESSION SET NLS_COMP=LINGUISTIC;
SQL> ALTER SESSION SET NLS_SORT=BINARY_CI;
SQL> SELECT ename FROM emp1 WHERE ename LIKE 'McC%e';
ENAME
----------------------
McCoye
Mccathye
2 rows selected
Example 5–9 Linguistic Comparison Binary Accent-Insensitive Sort
The following illustrates behavior with an accent-insensitive setting:
SQL> ALTER SESSION SET NLS_COMP=LINGUISTIC;
SQL> ALTER SESSION SET NLS_SORT=BINARY_AI;
SQL> SELECT ename FROM emp1 WHERE ename LIKE 'McC%e';
ENAME
----------------------
McCoye
Mccathye
McCafeé
Performing Linguistic Comparisons
5-16 Oracle Database Globalization Support Guide
3 rows selected
Example 5–10 Linguistic Comparisons Returning Fewer Rows
Some operations may return fewer rows after applying linguistic rules. For example,
with a binary setting, McAfee and Mcafee are different:
SQL> ALTER SESSION SET NLS_COMP=BINARY;
SQL> ALTER SESSION SET NLS_SORT=BINARY;
SQL> SELECT DISTINCT ename FROM emp2;
ENAME
----------------------
McAfee
Mcafee
McCoy
3 rows selected
However, with a case-insensitive setting, McAfee and Mcafee are the same:
SQL> ALTER SESSION SET NLS_COMP=LINGUISTIC;
SQL> ALTER SESSION SET NLS_SORT=BINARY_CI;
SQL> SELECT DISTINCT ename FROM emp2;
ENAME
----------------------
McAfee
McCoy
2 rows selected
In this example, either McAfee or Mcafee could be returned from the DISTINCT
operation. There is no guarantee exactly which one will be picked.
Example 5–11 Linguistic Comparisons Using XSPANISH
There are cases where characters the are same using binary comparison but different
using linguistic comparison. For example, with a binary setting, the character C in
Cindy, Chad, and Clara represents the same letter C:
SQL> ALTER SESSION SET NLS_COMP=BINARY;
SQL> ALTER SESSION SET NLS_SORT=BINARY;
SQL> SELECT ename FROM emp3 WHERE ename LIKE 'C%';
ENAME
----------------------
Cindy
Chad
Clara
3 rows selected
In a database session with the linguistic rule set to traditional Spanish, XSPANISH, ch
is treated as one character. So the letter c in Chad is different than the letter C in Cindy
and Clara:
SQL> ALTER SESSION SET NLS_COMP=LINGUISTIC;
SQL> ALTER SESSION SET NLS_SORT=XSPANISH;
SQL> SELECT ename FROM emp3 WHERE ename LIKE 'C%';
Using Linguistic Indexes
Linguistic Sorting and String Searching 5-17
ENAME
----------------------
Cindy
Clara
2 rows selected
And the letter c in combination ch is different than the c standing by itself:
SQL> SELECT REPLACE ('character', 'c', 't') "Changes" FROM DUAL;
Changes
---------------------
charatter
Using Linguistic Indexes
Linguistic sorting is language-specific and requires more data processing than binary
sorting. Using a binary sort for ASCII is accurate and fast because the binary codes for
ASCII characters reflect their linguistic order. When data in multiple languages is
stored in the database, you may want applications to sort the data returned from a
SELECT...ORDER BY statement according to different sort sequences depending on
the language. You can accomplish this without sacrificing performance by using
linguistic indexes. Although a linguistic index for a column slows down inserts and
updates, it greatly improves the performance of linguistic sorting with the ORDER BY
clause and the WHERE clause.
You can create a function-based index that uses languages other than English. The
index does not change the linguistic sort order determined by NLS_SORT. The
linquistic index simply improves the performance.
The following statement creates an index based on a German sort:
CREATE TABLE my_table(name VARCHAR(20) NOT NULL);
CREATE INDEX nls_index ON my_table (NLSSORT(name, 'NLS_SORT = German'));
/*The NOT NULL in the CREATE TABLE statement ensures that the index is used*/
After the index has been created, enter a SELECT statement similar to the following
example:
SELECT * FROM my_table ORDER BY name
WHERE name LIKE ’Hein%’;
It returns the result much faster than the same SELECT statement without a linguistic
index.
The rest of this section contains the following topics:
■Supported SQL Operations and Functions for Linguistic Indexes
Linguistic Indexes for Multiple Languages
■Requirements for Using Linguistic Indexes
See Also:
■Oracle Database Concepts
■Oracle Database SQL Reference for more information about
function-based indexes
Using Linguistic Indexes
5-18 Oracle Database Globalization Support Guide
Supported SQL Operations and Functions for Linguistic Indexes
Linguistic index support is available for the following collation-sensitive SQL
operations and SQL functions:
■Comparison conditions =, !=, >, <, >=, <=
■Range conditions BETWEEN | NOT BETWEEN
■IN | NOT IN
■ORDER BY
■GROUP BY
■LIKE (LIKE, LIKE2, LIKE4, LIKEC)
■DISTINCT
■UNIQUE
■UNION
■INTERSECT
■MINUS
The SQL functions in the following list cannot utilize linguistic index:
■INSTR (INSTR, INSTRB, INSTR2, INSTR4, INSTRC)
■MAX
■MIN
■REPLACE
■TRIM
■LTRIM
■RTRIM
■TRANSLATE
Linguistic Indexes for Multiple Languages
There are three ways to build linguistic indexes for data in multiple languages:
■Build a linguistic index for each language that the application supports. This
approach offers simplicity but requires more disk space. For each index, the rows
in the language other than the one on which the index is built are collated together
at the end of the sequence. The following example builds linguistic indexes for
French and German.
CREATE INDEX french_index ON employees (NLSSORT(employee_id, 'NLS_
SORT=FRENCH'));
CREATE INDEX german_index ON employees (NLSSORT(employee_id, 'NLS_
SORT=GERMAN'));
Oracle Database chooses the index based on the NLS_SORT session parameter or
the arguments of the NLSSORT function specified in the ORDER BY clause. For
example, if the NLS_SORT session parameter is set to FRENCH, then Oracle
Database uses french_index. When it is set to GERMAN, Oracle Database uses
german_index.
■Build a single linguistic index for all languages. This requires a language column
(LANG_COL in "Example: Setting Up a French Linguistic Index" on page 5-19) to be
Using Linguistic Indexes
Linguistic Sorting and String Searching 5-19
used as a parameter of the NLSSORT function. The language column contains
NLS_LANGUAGE values for the data in the column on which the index is built. The
following example builds a single linguistic index for multiple languages. With
this index, the rows with the same values for NLS_LANGUAGE are sorted together.
CREATE INDEX i ON t (NLSSORT(col, 'NLS_SORT=' || LANG_COL));
Queries choose an index based on the argument of the NLSSORT function specified
in the ORDER BY clause.
■Build a single linguistic index for all languages using one of the multilingual
linguistic sorts such as GENERIC_M or FRENCH_M. These indexes sort characters
according to the rules defined in ISO 14651. For example:
CREATE INDEX i on t (NLSSORT(col,
'NLS_SORT=GENERIC_M');
Requirements for Using Linguistic Indexes
The following are requirements for using linguistic indexes:
■Set NLS_SORT Appropriately
■Specify NOT NULL in a WHERE Clause If the Column Was Not Declared NOT
NULL
This section also includes:
■Example: Setting Up a French Linguistic Index
Set NLS_SORT Appropriately
The NLS_SORT parameter should indicate the linguistic definition you want to use for
the linguistic sort. If you want a French linguistic sort order, then NLS_SORT should be
set to FRENCH. If you want a German linguistic sort order, then NLS_SORT should be
set to GERMAN.
There are several ways to set NLS_SORT. You should set NLS_SORT as a client
environment variable so that you can use the same SQL statements for all languages.
Different linguistic indexes can be used when NLS_SORT is set in the client
environment.
Specify NOT NULL in a WHERE Clause If the Column Was Not Declared NOT NULL
When you want to use the ORDER BY column_name clause with a column that has a
linguistic index, include a WHERE clause like the following example:
WHERE NLSSORT(column_name) IS NOT NULL
This WHERE clause is not necessary if the column has already been defined as a NOT
NULL column in the schema.
Example: Setting Up a French Linguistic Index
The following example shows how to set up a French linguistic index. You may want
to set NLS_SORT as a client environment variable instead of using the ALTER SESSION
statement.
See Also: "Multilingual Linguistic Sorts" on page 5-3 for more
information about Unicode sorts
See Also: "NLS_SORT" on page 3-29
Searching Linguistic Strings
5-20 Oracle Database Globalization Support Guide
ALTER SESSION SET NLS_SORT='FRENCH';
CREATE INDEX test_idx ON test4(NLSSORT(name, 'NLS_SORT=FRENCH'));
SELECT * FROM test4 ORDER BY col;
ALTER SESSION SET NLS_COMP=LINGUISTIC;
SELECT * FROM test4 WHERE name > 'Henri';
Searching Linguistic Strings
Searching and sorting are related tasks. Organizing data and processing it in a
linguistically meaningful order is necessary for proper business processing. Searching
and matching data in a linguistically meaningful way depends on what sort order is
applied. For example, searching for all strings greater than c and less than f produces
different results depending on the value of NLS_SORT. In an ASCII binary sort the
search finds any strings that start with d or e but excludes entries that begin with
upper case D or E or accented e with a diacritic, such as ê. Applying an
accent-insensitive binary sort returns all strings that start with d, D, and accented e,
such as Ê or ê. Applying the same search with NLS_SORT set to XSPANISH also
returns strings that start with ch, because ch is treated as a composite character that
sorts between c and d in traditional Spanish. This chapter discusses the kinds of sorts
that Oracle Database offers and how they affect string searches by SQL and SQL
regular expressions.
SQL Regular Expressions in a Multilingual Environment
Regular expressions provide a powerful method of identifying patterns of strings
within a body of text. Usage ranges from a simple search for a string such as San
Francisco to the more complex task of extracting all URLs to finding all words
whose every second character is a vowel. SQL and PL/SQL support regular
expressions in Oracle Database 10g.
Traditional regular expression engines were designed to address only English text.
However, regular expression implementations can encompass a wide variety of
languages with characteristics that are very different from western European text. The
implementation of regular expressions in Oracle Database is based on the Unicode
Regular Expression Guidelines. The REGEXP SQL functions work with all character
sets that are supported as database character sets and national character sets.
Moreover, Oracle Database enhances the matching capabilities of the POSIX regular
expression constructs to handle the unique linguistic requirements of matching
multilingual data.
Oracle Database enhancements of the linguistic-sensitive operators are described in
the following sections:
■Character Range '[x-y]' in Regular Expressions
■Collation Element Delimiter '[. .]' in Regular Expressions
■Character Class '[: :]' in Regular Expressions
Note: The SQL functions MAX( ) and MIN( ) cannot use linguistic
indexes when NLS_COMP is set to LINGUISTIC.
See Also:
■"Linguistic Sort Features" on page 5-5
■"SQL Regular Expressions in a Multilingual Environment" on
page 5-20
SQL Regular Expressions in a Multilingual Environment
Linguistic Sorting and String Searching 5-21
■Equivalence Class '[= =]' in Regular Expressions
■Examples: Regular Expressions
Character Range '[x-y]' in Regular Expressions
According to the POSIX standard, a range in a regular expression includes all collation
elements between the start point and the end point of the range in the linguistic
definition of the current locale. Therefore, ranges in regular expressions are meant to
be linguistic ranges, not byte value ranges, because byte value ranges depend on the
platform, and the end user should not be expected to know the ordering of the byte
values of the characters. The semantics of the range expression must be independent of
the character set. This implies that a range such as [a-d] includes all the letters
between a and d plus all of those letters with diacritics, plus any special case collation
element such as ch in Traditional Spanish that is sorted as one character.
Oracle Database interprets range expressions as specified by the NLS_SORT parameter
to determine the collation elements covered by a given range. For example:
Expression: [a-d]e
NLS_SORT: BINARY
Does not match: cheremoya
NLS_SORT: XSPANISH
Matches: >>che<<remoya
Collation Element Delimiter '[. .]' in Regular Expressions
This construct is introduced by the POSIX standard to separate collating elements. A
collating element is a unit of collation and is equal to one character in most cases.
However, the collation sequence in some languages may define two or more characters
as a collating element. The historical regular expression syntax does not allow the user
to define ranges involving multicharacter collation elements. For example, there was
no way to define a range from a to ch because ch was interpreted as two separate
characters.
By using the collating element delimiter [. .], you can separate a multicharacter
collation element from other elements. For example, the range from a to ch can be
written as [a-[.ch.]]. It can also be used to separate single-character collating
elements. If you use [. .] to enclose a multicharacter sequence that is not a defined
collating element, then it is considered as a semantic error in the regular expression.
For example, [.ab.] is considered invalid if ab is not a defined multicharacter
collating element.
Character Class '[: :]' in Regular Expressions
In English regular expressions, the range expression can be used to indicate a character
class. For example, [a-z] can be used to indicate any lowercase letter. However, in
non-English regular expressions, this approach is not accurate unless a is the first
lowercase letter and z is the last lowercase letter in the collation sequence of the
language.
See Also:
■Oracle Database Application Developer's Guide - Fundamentals for
more information about regular expression syntax
■Oracle Database SQL Reference for more information about
REGEX SQL functions
SQL Regular Expressions in a Multilingual Environment
5-22 Oracle Database Globalization Support Guide
The POSIX standard introduces a new syntactical element to enable specifying explicit
character classes in a portable way. The [: :] syntax denotes the set of characters
belonging to a certain character class. The character class definition is based on the
character set classification data.
Equivalence Class '[= =]' in Regular Expressions
Oracle Database also supports equivalence classes through the [= =] syntax as
recommended by the POSIX standard. A base letter and all of the accented versions of
the base constitute an equivalence class. For example, the equivalence class [=a=]
matches ä as well as â. The current implementation does not support matching of
Unicode composed and decomposed forms for performance reasons. For example, ä (a
umlaut) does not match 'a followed by umlaut'.
Examples: Regular Expressions
The following examples show regular expression matches.
Example 5–12 Case-Insensitive Match Using the NLS_SORT Value
Case sensitivity in an Oracle Database regular expression match is determined at two
levels: the NLS_SORT initialization parameter and the runtime match option. The
REGEXP functions inherit the case-sensitivity behavior from the value of NLS_SORT by
default. The value can also be explicitly overridden by the runtime match option 'c'
(case sensitive) or 'i' (case insensitive).
Expression: catalog(ue)?
NLS_SORT: GENERIC_M_CI
Matches:
>>Catalog<<
>>catalogue<<
>>CATALOG<<
Oracle Database SQL syntax:
SQL> ALTER SESSION SET NLS_SORT='GENERIC_M_CI';
SQL> SELECT col FROM test WHERE REGEXP_LIKE(col,'catalog(ue)?');
Example 5–13 Case Insensitivity Overridden by the Runtime Match Option
Expression: catalog(ue)?
NLS_SORT: GENERIC_M_CI
Match option: 'c'
Matches:
>>catalogue<<
Does not match:
Catalog
CATALOG
Oracle Database SQL syntax:
SQL> ALTER SESSION SET NLS_SORT='GENERIC_M_CI';
SQL> SELECT col FROM test WHERE REGEXP_LIKE(col,'catalog(ue)?','c');
Example 5–14 Matching with the Collation Element Operator [..]
Expression: [^-a-[.ch.]]+ /*with NLS_SORT set to xspanish*/
Matches:
>>driver<<
Does not match:
SQL Regular Expressions in a Multilingual Environment
Linguistic Sorting and String Searching 5-23
cab
Oracle Database SQL syntax:
SQL> SELECT col FROM test WHERE REGEXP_LIKE(col,'[^-a-[.ch.]]+');
Example 5–15 Matching with the Character Class Operator [::]
This expression looks for 6-character strings with lowercase characters. Note that
accented characters are matched as lowercase characters.
Expression: [[:lower:]]{6}
Database character set: WE8ISO8859P1
Matches:
>>maître<<
>>mòbile<<
>>pájaro<<
>>zurück<<
Oracle Database SQL syntax:
SQL> SELECT col FROM test WHERE REGEXP_LIKE(col,'[[:lower:]]{6}');
Example 5–16 Matching with the Base Letter Operator [==]
Expression: r[[=e=]]sum[[=e=]]
Matches:
>>resume<<
>>résumé<<
>>résume<<
>>resumé<<
Oracle Database SQL syntax:
SQL> SELECT col FROM test WHERE REGEXP_LIKE(col,'r[[=e=]]sum[[=e=]]');
See Also:
■Oracle Database Application Developer's Guide - Fundamentals for
more information about regular expression syntax
■Oracle Database SQL Reference for more information about
REGEX SQL functions
SQL Regular Expressions in a Multilingual Environment
5-24 Oracle Database Globalization Support Guide
Supporting Multilingual Databases with Unicode 6-1
6
Supporting Multilingual Databases with
Unicode
This chapter illustrates how to use Unicode in an Oracle Database environment. This
chapter includes the following topics:
■Overview of Unicode
■What is Unicode?
■Implementing a Unicode Solution in the Database
■Unicode Case Studies
■Designing Database Schemas to Support Multiple Languages
Overview of Unicode
Unicode is a character encoding system that defines every character in most of the
spoken languages in the world.
To overcome the limitations of existing character encodings, several organizations
began working on the creation of a global character set in the late 1980s. The need for
this became even greater with the development of the World Wide Web in the
mid-1990s. The Internet has changed how companies do business, with an emphasis
on the global market that has made a universal character set a major requirement.
A global character set needs to fulfill the following conditions:
■Contain all major living scripts
■Support legacy data and implementations
■Be simple enough that a single implementation of an application is sufficient for
worldwide use
A global character set should also have the following capabilities:
■Support multilingual users and organizations
■Conform to international standards
■Enable worldwide interchange of data
Unicode, which is now in wide use, meets all of the requirments and capabilities of a
global character set.
What is Unicode?
6-2 Oracle Database Globalization Support Guide
What is Unicode?
Unicode is a universally encoded character set that enables information from any
language to be stored using a single character set. Unicode provides a unique code
value for every character, regardless of the platform, program, or language.
The Unicode standard has been adopted by many software and hardware vendors.
Many operating systems and browsers now support Unicode. Unicode is required by
standards such as XML, Java, JavaScript, LDAP, and WML. It is also synchronized
with the ISO/IEC 10646 standard.
Oracle Database introduced Unicode as a database character set in Oracle Database 7.
In Oracle Database 11g, Unicode support has been expanded. Oracle Database 11g
release 1 supports Unicode 5.0.
This section contains the following topics:
■Supplementary Characters
■Unicode Encodings
■Support for Unicode in Oracle Database
Supplementary Characters
The first version of Unicode was a 16-bit, fixed-width encoding that used two bytes to
encode each character. This enabled 65,536 characters to be represented. However,
more characters need to be supported, especially additional CJK ideographs that are
important for the Chinese, Japanese, and Korean markets.
Unicode defines supplementary characters to meet this need. It uses two 16-bit code
points (also known as supplementary characters) to represent a single character. The
implementation of supplementary characters enables more than a million additional
characters to be defined.
Adding supplementary characters has increased the complexity of Unicode; however,
this is less complex than managing several different encodings in the same
configuration.
Unicode Encodings
The Unicode standard encodes characters in different ways: UTF-8, UCS-2, and
UTF-16. Conversion between different Unicode encodings is a simple bit-wise
operation that is defined in the Unicode standard.
This section contains the following topics:
■UTF-8 Encoding
■UCS-2 Encoding
■UTF-16 Encoding
■Examples: UTF-16, UTF-8, and UCS-2 Encoding
UTF-8 Encoding
UTF-8 is the 8-bit encoding of Unicode. It is a variable-width encoding and a strict
superset of ASCII. This means that each and every character in the ASCII character set
See Also: http://www.unicode.org for more information
about the Unicode standard
What is Unicode?
Supporting Multilingual Databases with Unicode 6-3
is available in UTF-8 with the same code point values. One Unicode character can be 1
byte, 2 bytes, 3 bytes, or 4 bytes in UTF-8 encoding. Characters from the European
scripts are represented in either 1 or 2 bytes. Characters from most Asian scripts are
represented in 3 bytes. Supplementary characters are represented in 4 bytes.
UTF-8 is the Unicode encoding used for HTML and most Internet browsers.
The benefits of UTF-8 are as follows:
■Compact storage requirement for European scripts because it is a strict superset of
ASCII
■Ease of migration between ASCII-based characters sets and UTF-8
UCS-2 Encoding
UCS-2 is a fixed-width, 16-bit encoding. Each character is 2 bytes. UCS-2 is the
Unicode encoding used by Java and Microsoft Windows . UCS-2 supports characters
defined for Unicode 3.0, so there is no support for supplementary characters.
The benefits of UCS-2 over UTF-8 are as follows:
■More compact storage for Asian scripts, because all characters are two bytes
■Faster string processing, because characters are fixed-width
■Better compatibility with Java and Microsoft clients
UTF-16 Encoding
UTF-16 encoding is the 16-bit encoding of Unicode. UTF-16 is an extension of UCS-2
because it supports the supplementary characters by using two UCS-2 code points for
each supplementary character. UTF-16 is a strict superset of UCS-2.
One character can be either 2 bytes or 4 bytes in UTF-16. Characters from European
and most Asian scripts are represented in 2 bytes. Supplementary characters are
represented in 4 bytes. UTF-16 is the main Unicode encoding used by Microsoft
Windows 2000.
The benefits of UTF-16 over UTF-8 are as follows:
■More compact storage for Asian scripts because most of the commonly used Asian
characters are represented in two bytes.
■Better compatibility with Java and Microsoft clients
See Also:
■"Supplementary Characters" on page 6-2
■Table B–2, " Unicode Character Code Ranges for UTF-8
Character Codes" on page B-2
See Also: "Supplementary Characters" on page 6-2
See Also:
■"Supplementary Characters" on page 6-2
■Table B–1, " Unicode Character Code Ranges for UTF-16
Character Codes" on page B-1
What is Unicode?
6-4 Oracle Database Globalization Support Guide
Examples: UTF-16, UTF-8, and UCS-2 Encoding
Figure 6–1 shows some characters and their character codes in UTF-16, UTF-8, and
UCS-2 encoding. The last character is a treble clef (a music symbol), a supplementary
character.
Figure 6–1 UTF-16, UTF-8, and UCS-2 Encoding Examples
Support for Unicode in Oracle Database
Oracle Database began supporting Unicode as a database character set in release 7.
Table 6–1 summarizes the Unicode character sets supported by Oracle Database.
Table 6–1 Unicode Character Sets Supported by Oracle Database
Character Set
Supported in
RDBMS
Release
Unicode
Encoding Unicode Version
Database
Character Set
National
Character Set
AL24UTFFSS 7.2 - 8iUTF-8 1.1 Yes No
UTF8 8.0 - 11gUTF-8 For Oracle Database
release 8.0 through
Oracle8i release 8.1.6: 2.1
For Oracle8i Database
release 8.1.7 and later: 3.0
Yes Yes (Oracle9i
Database and
Oracle Database
10g only)
0041
0063
00F6
4E9C
D834 DD1E
41
63
C3 B6
E4 BA 9C
F0 9D 84 9E
A
c
Ö
Character UTF-16
0041
0063
00F6
4E9C
N/A
UCS-2UTF-8
Implementing a Unicode Solution in the Database
Supporting Multilingual Databases with Unicode 6-5
Implementing a Unicode Solution in the Database
Unicode characters can be stored in an Oracle database in two ways:
■You can create a Unicode database that enables you to store UTF-8 encoded
characters as SQL CHAR datatypes (CHAR, VARCHAR2, CLOB, and LONG).
■If you prefer to implement Unicode support incrementally, or if you need to
support multilingual data only in certain columns, then you can store Unicode
data in either the UTF-16 or UTF-8 encoding form in SQL NCHAR datatypes
(NCHAR, NVARCHAR2, and NCLOB). The SQL NCHAR datatypes are called Unicode
datatypes because they are used only for storing Unicode data.
The following sections explain how to use the two Unicode solutions and how to
choose between them:
■Enabling Multilingual Support with Unicode Databases
■Enabling Multilingual Support with Unicode Datatypes
■How to Choose Between a Unicode Database and a Unicode Datatype Solution
UTFE 8.0 - 11gUTF-EBCDIC For Oracle8i Database
releases 8.0 through 8.1.6:
2.1
For Oracle8i Database
release 8.1.7 and later: 3.0
Yes No
AL32UTF8 9i - 11gUTF-8 Oracle9i Database Release
1: 3.0
Oracle9i Database Release
2: 3.1
Oracle Database 10g,
Release 1: 3.2
Oracle Database 10g,
Release2: 4.0
Oracle Database 11g,
Release 1: 5.0
Yes No
AL16UTF16 9i - 11gUTF-16 Oracle9i Database Release
1: 3.0
Oracle9i Database Release
2: 3.1
Oracle Database 10g,
Release 1: 3.2
Oracle Database 10g,
Release 2: 4.0
Oracle Database 11g,
Release 1: 5.0
No Yes
Note: You can combine a Unicode database solution with a
Unicode datatype solution.
Table 6–1 (Cont.) Unicode Character Sets Supported by Oracle Database
Character Set
Supported in
RDBMS
Release
Unicode
Encoding Unicode Version
Database
Character Set
National
Character Set
Implementing a Unicode Solution in the Database
6-6 Oracle Database Globalization Support Guide
■Comparing Unicode Character Sets for Database and Datatype Solutions
Enabling Multilingual Support with Unicode Databases
The database character set specifies the encoding to be used in the SQL CHAR
datatypes as well as the metadata such as table names, column names, and SQL
statements. A Unicode database is a database with a UTF-8 character set as the
database character set. There are three Oracle character sets that implement the UTF-8
encoding. The first two are designed for ASCII-based platforms while the third one
should be used on EBCDIC platforms.
■AL32UTF8
The AL32UTF8 character set supports the latest version of the Unicode standard. It
encodes characters in one, two, or three bytes. Supplementary characters require
four bytes. It is for ASCII-based platforms.
■UTF8
The UTF8 character set encodes characters in one, two, or three bytes. It is for
ASCII-based platforms.
Supplementary characters inserted into a UTF8 database do not corrupt the data in
the database. A supplementary character is treated as two separate, user-defined
characters that occupy 6 bytes. Oracle recommends that you switch to AL32UTF8
for full support of supplementary characters in the database character set.
■UTFE
The UTFE character set is for EBCDIC platforms. It is similar to UTF8 on ASCII
platforms, but it encodes characters in one, two, three, and four bytes.
Supplementary characters are converted as two 4-byte characters.
Example 6–1 Creating a Database with a Unicode Character Set
To create a database with the AL32UTF8 character set, use the CREATE DATABASE
statement and include the CHARACTER SET AL32UTF8 clause. For example:
CREATE DATABASE sample
CONTROLFILE REUSE
LOGFILE
GROUP 1 ('diskx:log1.log', 'disky:log1.log') SIZE 50K,
GROUP 2 ('diskx:log2.log', 'disky:log2.log') SIZE 50K
MAXLOGFILES 5
MAXLOGHISTORY 100
MAXDATAFILES 10
MAXINSTANCES 2
ARCHIVELOG
CHARACTER SET AL32UTF8
NATIONAL CHARACTER SET AL16UTF16
DATAFILE
'disk1:df1.dbf' AUTOEXTEND ON,
'disk2:df2.dbf' AUTOEXTEND ON NEXT 10M MAXSIZE UNLIMITED
DEFAULT TEMPORARY TABLESPACE temp_ts
UNDO TABLESPACE undo_ts
SET TIME_ZONE = '+02:00';
Note: Specify the database character set when you create the
database.
Implementing a Unicode Solution in the Database
Supporting Multilingual Databases with Unicode 6-7
Enabling Multilingual Support with Unicode Datatypes
An alternative to storing Unicode data in the database is to use the SQL NCHAR
datatypes (NCHAR, NVARCHAR, NCLOB). You can store Unicode characters in columns
of these datatypes regardless of how the database character set has been defined. The
NCHAR datatype is exclusively a Unicode datatype, which means that it stores data
encoded as Unicode.
You can create a table using the NVARCHAR2 and NCHAR datatypes. The column length
specified for the NCHAR and NVARCHAR2 columns always equals the number of
characters instead of the number of bytes:
CREATE TABLE product_information
( product_id NUMBER(6)
, product_name NVARCHAR2(100)
, product_description VARCHAR2(1000));
The encoding used in the SQL NCHAR datatypes is the national character set specified
for the database. You can specify one of the following Oracle character sets as the
national character set:
■AL16UTF16
This is the default character set for SQL NCHAR datatypes. This character set
encodes Unicode data in the UTF-16 encoding. It supports supplementary
characters, which are stored as four bytes.
■UTF8
When UTF8 is specified for SQL NCHAR datatypes, the data stored in the SQL
datatypes is in UTF-8 encoding.
You can specify the national character set for the SQL NCHAR datatypes when you
create a database using the CREATE DATABASE statement with the NATIONAL
CHARACTER SET clause. The following statement creates a database with
WE8ISO8859P1 as the database character set and AL16UTF16 as the national character
set.
Example 6–2 Creating a Database with a National Character Set
CREATE DATABASE sample
CONTROLFILE REUSE
LOGFILE
GROUP 1 ('diskx:log1.log', 'disky:log1.log') SIZE 50K,
GROUP 2 ('diskx:log2.log', 'disky:log2.log') SIZE 50K
MAXLOGFILES 5
MAXLOGHISTORY 100
MAXDATAFILES 10
MAXINSTANCES 2
ARCHIVELOG
CHARACTER SET WE8ISO8859P1
NATIONAL CHARACTER SET AL16UTF16
DATAFILE
'disk1:df1.dbf' AUTOEXTEND ON,
'disk2:df2.dbf' AUTOEXTEND ON NEXT 10M MAXSIZE UNLIMITED
DEFAULT TEMPORARY TABLESPACE temp_ts
UNDO TABLESPACE undo_ts
SET TIME_ZONE = '+02:00';
Implementing a Unicode Solution in the Database
6-8 Oracle Database Globalization Support Guide
How to Choose Between a Unicode Database and a Unicode Datatype Solution
To choose the correct Unicode solution for your database, consider the following
questions:
■Programming environment: What are the main programming languages used in
your applications? How do they support Unicode?
■Ease of migration: How easily can your data and applications be migrated to take
advantage of the Unicode solution?
■Types of data: Is your data mostly Asian or European? Do you need to store
multilingual documents into LOB columns?
■Types of applications: What type of applications are you implementing: a
packaged application or a customized end-user application?
This section describes some general guidelines for choosing a Unicode database or a
Unicode datatype solution. The final decision largely depends on your exact
environment and requirements. This section contains the following topics:
■When Should You Use a Unicode Database?
■When Should You Use Unicode Datatypes?
When Should You Use a Unicode Database?
Use a Unicode database in the situations described in Table 6–2.
When Should You Use Unicode Datatypes?
Use Unicode datatypes in the situations described in Table 6–3.
Table 6–2 Using a Unicode Database
Situation Explanation
You need easy code
migration for Java or
PL/SQL.
If your existing application is mainly written in Java and PL/SQL and your main
concern is to minimize the code changes required to support multiple languages, then
you may want to use a Unicode database solution. If the datatypes used to stored
data remain as SQL CHAR datatypes, then the Java and PL/SQL code that accesses
these columns does not need to change.
You have evenly
distributed multilingual
data.
If the multilingual data is evenly distributed in existing schema tables and you are not
sure which tables contain multilingual data, then you should use a Unicode database
because it does not require you to identify the kind of data that is stored in each
column.
Your SQL statements and
PL/SQL code contain
Unicode data.
You must use a Unicode database. SQL statements and PL/SQL code are converted
into the database character set before being processed. If the SQL statements and
PL/SQL code contain characters that cannot be converted to the database character
set, then those characters are lost. A common place to use Unicode data in a SQL
statement is in a string literal.
You want to store
multilingual documents in
BLOB format and use
Oracle Text for content
searching.
You must use a Unicode database. The BLOB data is converted to the database
character set before being indexed by Oracle Text. If your database character set is not
UTF8, then data is lost when the documents contain characters that cannot be
converted to the database character set.
Implementing a Unicode Solution in the Database
Supporting Multilingual Databases with Unicode 6-9
Comparing Unicode Character Sets for Database and Datatype Solutions
Oracle provides two solutions to store Unicode characters in the database: a Unicode
database solution and a Unicode datatype solution. After you select the Unicode
database solution, the Unicode datatype solution, or a combination of both, you then
determine the character set to be used in the Unicode database or the Unicode
datatype.
Table 6–4 contains advantages and disadvantages of character sets for a Unicode
database solution. The Oracle character sets that can be Unicode database character
sets are AL32UTF8, UTF8, and UTFE.
Table 6–3 Using Unicode Datatypes
Situation Explanation
You want to add
multilingual support
incrementally.
If you want to add Unicode support to the existing database without migrating the
character set, then consider using Unicode datatypes to store Unicode data. You can add
columns of the SQL NCHAR datatypes to existing tables or new tables to support multiple
languages incrementally.
You want to build a
packaged application. If you are building a packaged application to sell to customers, then you may want to
build the application using SQL NCHAR datatypes. The SQL NCHAR datatype is a reliable
Unicode datatype in which the data is always stored in Unicode, and the length of the
data is always specified in UTF-16 code units. As a result, you need to test the application
only once. The application will run on customer databases with any database character
set.
You want better
performance with
single-byte database
character sets.
If performance is your main concern, then consider using a single-byte database character
set and storing Unicode data in the SQL NCHAR datatypes.
You require UTF-16
support in Windows
clients.
If your applications are written in Visual C/C++ or Visual Basic running on Windows,
then you may want to use the SQL NCHAR datatypes. You can store UTF-16 data in SQL
NCHAR datatypes in the same way that you store it in the wchar_t buffer in Visual
C/C++ and string buffer in Visual Basic. You can avoid buffer overflow in client
applications because the length of the wchar_t and string datatypes match the length
of the SQL NCHAR datatypes in the database.
Note: You can use a Unicode database with Unicode datatypes.
Implementing a Unicode Solution in the Database
6-10 Oracle Database Globalization Support Guide
Table 6–5 contains advantages and disadvantages of different character sets for a
Unicode datatype solution. The Oracle character sets that can be national character sets
are AL16UTF16 and UTF8. The default is AL16UTF16.
Table 6–4 Character Set Advantages and Disadvantages for a Unicode Database Solution
Database
Character Set Advantages Disadvantages
AL32UTF8 ■Supplementary characters are stored in 4
bytes, so there is no data conversion
when supplementary characters are
retrieved and inserted if the client setting
is UTF-8.
■The storage for supplementary characters
requires less disk space in AL32UTF8
than in UTF8.
■You cannot specify the length of SQL CHAR types in
number of UCS-2 code points for supplementary
characters. Supplementary characters are treated as
one code point rather than the standard two code
points.
■The binary order for SQL CHAR columns is different
from the binary order of SQL NCHAR columns when
the data consists of supplementary characters. As a
result, CHAR columns and NCHAR columns do not
always have the same sort for identical strings.
UTF8 ■You can specify the length of SQL CHAR
types in number of UCS-2 code points.
■The binary order of the SQL CHAR
columns is always the same as the binary
order of the SQL NCHAR columns when
the data consists of the same
supplementary characters. As a result,
CHAR columns and NCHAR columns have
the same sort for identical strings.
■Supplementary characters are stored as 6 bytes
instead of the 4 bytes defined by Unicode 4.0. As a
result, Oracle has to convert data for
supplementary characters if the client setting is
UTF-8.
UTFE ■This is the only Unicode character set for
the EBCDIC platform.
■You can specify the length of SQL CHAR
types in number of UCS-2 code points.
■The binary order of the SQL CHAR
columns is always the same as the binary
order of the SQL NCHAR columns when
the data consists of the same
supplementary characters. As a result,
CHAR columns and NCHAR columns have
the same sort for identical strings.
■Supplementary character are stored as 8 bytes (two
4-byte sequences) instead of the 5 bytes defined by
the Unicode standard. As a result, Oracle has to
convert data for those supplementary characters.
■UTFE is not a standard encoding in the Unicode
standard. As a result, clients requiring standard
UTF-8 encoding must convert data from UTFE to
the standard encoding when data is retrieved and
inserted.
Unicode Case Studies
Supporting Multilingual Databases with Unicode 6-11
Unicode Case Studies
This section describes typical scenarios for storing Unicode characters in an Oracle
database:
■Example 6–3, "Unicode Solution with a Unicode Database"
■Example 6–4, "Unicode Solution with Unicode Datatypes"
■Example 6–5, "Unicode Solution with a Unicode Database and Unicode Datatypes"
Example 6–3 Unicode Solution with a Unicode Database
An American company running a Java application would like to add German and
French support in the next release of the application. They would like to add Japanese
support at a later time. The company currently has the following system configuration:
■The existing database has a database character set of US7ASCII.
■All character data in the existing database is composed of ASCII characters.
■PL/SQL stored procedures are used in the database.
■The database is about 300 GB.
■There is a nightly downtime of 4 hours.
In this case, a typical solution is to choose UTF8 for the database character set because
of the following reasons:
Table 6–5 Character Set Advantages and Disadvantages for a Unicode Datatype Solution
National
Character Set Advantages Disadvantages
AL16UTF16 ■Asian data in AL16UTF16 is usually more
compact than in UTF8. As a result, you save disk
space and have less disk I/O when most of the
multilingual data stored in the database is Asian
data.
■It is usually faster to process strings encoded in
the AL16UTF16 character set than strings encoded
in UTF8 because Oracle processes most characters
in an AL16UTF16 encoded string as fixed-width
characters.
■The maximum length limits for the NCHAR and
NVARCHAR2 columns are 1000 and 2000
characters, respectively. Because the data is
fixed-width, the lengths are guaranteed.
■European ASCII data requires more disk
space to store in AL16UTF16 than in UTF8.
If most of your data is European data, then
it uses more disk space than if it were UTF8
data.
■The maximum lengths for NCHAR and
NVARCHAR2 are 1000 and 2000 characters,
which is less than the lengths for NCHAR
(2000) and NVARCHAR2 (4000) in UTF8.
UTF8 ■European data in UTF8 is usually more compact
than in AL16UTF16. As a result, you save disk
space and have better response time when most of
the multilingual data stored in the database is
European data.
■The maximum lengths for the NCHAR and
NVARCHAR2 columns are 2000 and 4000 characters
respectively, which is more than those for NCHAR
(1000) and NVARCHAR2 (2000) in AL16UTF16.
Although the maximum lengths of the NCHAR and
NVARCHAR2 columns are larger in UTF8, the
actual storage size is still bound by the byte limits
of 2000 and 4000 bytes, respectively. For example,
you can store 4000 UTF8 characters in an
NVARCHAR2 column if all the characters are single
byte, but only 4000/3 characters if all the
characters are three bytes.
■Asian data requires more disk space to
store in UTF8 than in AL16UTF16. If most
of your data is Asian data, then disk space
usage is not less efficient than when the
character set is AL16UTF16.
■Although you can specify larger length
limits for NCHAR and NVARCHAR, you are
not guaranteed to be able to insert the
number of characters specified by these
limits. This is because UTF8 allows
variable-width characters.
■It is usually slower to process strings
encoded in UTF8 than strings encoded in
AL16UTF16 because UTF8 encoded strings
consist of variable-width characters.
Unicode Case Studies
6-12 Oracle Database Globalization Support Guide
■The database is very large and the scheduled downtime is short. Fast migration of
the database to Unicode is vital. Because the database is in US7ASCII, the easiest
and fastest way of enabling the database to support Unicode is to switch the
database character set to UTF8 by running the CSALTER script. No data
conversion is required because US7ASCII is a subset of UTF8.
■Because most of the code is written in Java and PL/SQL, changing the database
character set to UTF8 is unlikely to break existing code. Unicode support is
automatically enabled in the application.
■Because the application supports French, German, and Japanese, there are few
supplementary characters. Both AL32UTF8 and UTF8 are suitable.
Example 6–4 Unicode Solution with Unicode Datatypes
A European company that runs its applications mainly on Windows platforms wants
to add new Windows applications written in Visual C/C++. The new applications will
use the existing database to support Japanese and Chinese customer names. The
company currently has the following system configuration:
■The existing database has a database character set of WE8ISO8859P1.
■All character data in the existing database is composed of Western European
characters.
■The database is around 50 GB.
A typical solution is take the following actions:
■Use NCHAR and NVARCHAR2 datatypes to store Unicode characters
■Keep WE8ISO8859P1 as the database character set
■Use AL16UTF16 as the national character set
The reasons for this solution are:
■Migrating the existing database to a Unicode database requires data conversion
because the database character set is WE8ISO8859P1 (a Latin-1 character set),
which is not a subset of UTF8. As a result, there will be some overhead in
converting the data to UTF8.
■The additional languages are supported in new applications only. They do not
depend on the existing applications or schemas. It is simpler to use the Unicode
datatype in the new schema and keep the existing schemas unchanged.
■Only customer name columns require Unicode support. Using a single NCHAR
column meets the customer's requirements without migrating the entire database.
■Because the languages to be supported are mostly Asian languages, AL16UTF16
should be used as the national character set so that disk space is used more
efficiently.
■The lengths of the SQL NCHAR datatypes are defined as number of characters. This
is the same as how they are treated when using wchar_t strings in Windows
C/C++ programs. This reduces programming complexity.
■Existing applications using the existing schemas are unaffected.
Example 6–5 Unicode Solution with a Unicode Database and Unicode Datatypes
A Japanese company wants to develop a new Java application. The company expects
that the application will support as many languages as possible in the long run.
Designing Database Schemas to Support Multiple Languages
Supporting Multilingual Databases with Unicode 6-13
■In order to store documents as is, the company decided to use the BLOB datatype
to store documents of multiple languages.
■The company may also want to generate UTF-8 XML documents from the
relational data for business-to-business data exchange.
■The back-end has Windows applications written in C/C++ using ODBC to access
the Oracle database.
In this case, the typical solution is to create a Unicode database using AL32UTF8 as the
database character set and use the SQL NCHAR datatypes to store multilingual data.
The national character set should be set to AL16UTF16. The reasons for this solution
are as follows:
■When documents of different languages are stored in BLOB format, Oracle Text
requires the database character set to be one of the UTF-8 character sets. Because
the applications may retrieve relational data as UTF-8 XML format (where
supplementary characters are stored as four bytes), AL32UTF8 should be used as
the database character set to avoid data conversion when UTF-8 data is retrieved
or inserted.
■Because applications are new and written in both Java and Windows C/C++, the
company should use the SQL NCHAR datatype for its relational data. Both Java and
Windows support the UTF-16 character datatype, and the length of a character
string is always measured in the number of characters.
■If most of the data is for Asian languages, then AL16UTF16 should be used with
the SQL NCHAR datatypes because AL16UTF16 offers better storage efficiency.
Designing Database Schemas to Support Multiple Languages
In addition to choosing a Unicode solution, the following issues should be taken into
consideration when the database schema is designed to support multiple languages:
■Specifying Column Lengths for Multilingual Data
■Storing Data in Multiple Languages
■Storing Documents in Multiple Languages in LOB Datatypes
■Creating Indexes for Searching Multilingual Document Contents
Specifying Column Lengths for Multilingual Data
When you use NCHAR and NVARCHAR2 datatypes for storing multilingual data, the
column size specified for a column is defined in number of characters. (The number of
characters means the number of Unicode code units.) Table 6–6 shows the maximum
size of the NCHAR and NVARCHAR2 datatypes for the AL16UTF16 and UTF8 national
character sets.
When you use CHAR and VARCHAR2 datatypes for storing multilingual data, the
maximum length specified for each column is, by default, in number of bytes. If the
Table 6–6 Maximum Datatype Size
National Character Set
Maximum Column Size of NCHAR
Datatype
Maximum Column Size of
NVARCHAR2 Datatype
AL16UTF16 1000 characters 2000 characters
UTF8 2000 bytes 4000 bytes
Designing Database Schemas to Support Multiple Languages
6-14 Oracle Database Globalization Support Guide
database needs to support Thai, Arabic, or multibyte languages such as Chinese and
Japanese, then the maximum lengths of the CHAR, VARCHAR, and VARCHAR2 columns
may need to be extended. This is because the number of bytes required to encode these
languages in UTF8 or AL32UTF8 may be significantly larger than the number of bytes
for encoding English and Western European languages. For example, one Thai
character in the Thai character set requires 3 bytes in UTF8 or AL32UTF8. In addition,
the maximum column lengths for CHAR, VARCHAR, and VARCHAR2 datatypes are 2000
bytes, 4000 bytes, and 4000 bytes respectively. If applications need to store more than
4000 bytes, then they should use the CLOB datatype.
Storing Data in Multiple Languages
The Unicode character set includes characters of most written languages around the
world, but it does not contain information about the language to which a given
character belongs. In other words, a character such as ä does not contain information
about whether it is a French or German character. In order to provide information in
the language a user desires, data stored in a Unicode database should accompany the
language information to which the data belongs.
There are many ways for a database schema to relate data to a language. The following
sections discuss different approaches:
■Store Language Information with the Data
■Select Translated Data Using Fine-Grained Access Control
Store Language Information with the Data
For data such as product descriptions or product names, you can add a language
column (language_id) of CHAR or VARCHAR2 datatype to the product table to
identify the language of the corresponding product information. This enables
applications to retrieve the information in the desired language. The possible values
for this language column are the 3-letter abbreviations of the valid NLS_LANGUAGE
values of the database.
You can also create a view to select the data of the current language. For example:
ALTER TABLE scott.product_information ADD (language_id VARCHAR2(50)):
CREATE OR REPLACE VIEW product AS
SELECT product_id, product_name
FROM product_information
WHERE language_id = SYS_CONTEXT('USERENV','LANG');
Select Translated Data Using Fine-Grained Access Control
Fine-grained access control enables you to limit the degree to which a user can view
information in a table or view. Typically, this is done by appending a WHERE clause.
When you add a WHERE clause as a fine-grained access policy to a table or view, Oracle
automatically appends the WHERE clause to any SQL statements on the table at run
time so that only those rows satisfying the WHERE clause can be accessed.
You can use this feature to avoid specifying the desired language of a user in the
WHERE clause in every SELECT statement in your applications. The following WHERE
clause limits the view of a table to the rows corresponding to the desired language of a
user:
See Also: Appendix A, "Locale Data" for a list of NLS_LANGUAGE
values and their abbreviations
Designing Database Schemas to Support Multiple Languages
Supporting Multilingual Databases with Unicode 6-15
WHERE language_id = SYS_CONTEXT('userenv', 'LANG')
Specify this WHERE clause as a fine-grained access policy for product_information
as follows:
CREATE FUNCTION func1 (sch VARCHAR2 , obj VARCHAR2 )
RETURN VARCHAR2(100);
BEGIN
RETURN 'language_id = SYS_CONTEXT(''userenv'', ''LANG'')';
END
/
DBMS_RLS.ADD_POLICY ('scott', 'product_information', 'lang_policy', 'scott',
'func1', 'select');
Then any SELECT statement on the product_information table automatically
appends the WHERE clause.
Storing Documents in Multiple Languages in LOB Datatypes
You can store documents in multiple languages in CLOB, NCLOB, or BLOB datatypes
and set up Oracle Text to enable content search for the documents.
Data in CLOB columns is stored in a format that is compatible with UCS-2 when the
database character set is multibyte, such as UTF8 or AL32UTF8. This means that the
storage space required for an English document doubles when the data is converted.
Storage for an Asian language document in a CLOB column requires less storage space
than the same document in a LONG column using UTF8, typically around 30% less,
depending on the contents of the document.
Documents in NCLOB format are also stored in a proprietary format that is compatible
with UCS-2 regardless of the database character set or national character set. The
storage space requirement is the same as for CLOB data. Document contents are
converted to UTF-16 when they are inserted into a NCLOB column. If you want to store
multilingual documents in a non-Unicode database, then choose NCLOB. However,
content search on NCLOB is not yet supported.
Documents in BLOB format are stored as they are. No data conversion occurs during
insertion and retrieval. However, SQL string manipulation functions (such as LENGTH
or SUBSTR) and collation functions (such as NLS_SORT and ORDER BY) cannot be
applied to the BLOB datatype.
Table 6–7 lists the advantages and disadvantages of the CLOB, NCLOB, and BLOB
datatypes when storing documents:
See Also: Oracle Database Application Developer's Guide -
Fundamentals for more information about fine-grained access
control
Designing Database Schemas to Support Multiple Languages
6-16 Oracle Database Globalization Support Guide
Creating Indexes for Searching Multilingual Document Contents
Oracle Text enables you to build indexes for content search on multilingual documents
stored in CLOB format and BLOB format. It uses a language-specific lexer to parse the
CLOB or BLOB data and produces a list of searchable keywords.
Create a multilexer to search multilingual documents. The multilexer chooses a
language-specific lexer for each row, based on a language column. This section
describes the high level steps to create indexes for documents in multiple languages. It
contains the following topics:
■Creating Multilexers
■Creating Indexes for Documents Stored in the CLOB Datatype
■Creating Indexes for Documents Stored in the BLOB Datatype
Creating Multilexers
The first step in creating the multilexer is the creation of language-specific lexer
preferences for each language supported. The following example creates English,
German, and Japanese lexers with PL/SQL procedures:
ctx_ddl.create_preference('english_lexer', 'basic_lexer');
ctx_ddl.set_attribute('english_lexer','index_themes','yes');
ctx_ddl.create_preference('german_lexer', 'basic_lexer');
ctx_ddl.set_attribute('german_lexer','composite','german');
ctx_ddl.set_attribute('german_lexer','alternate_spelling','german');
ctx_ddl.set_attribute('german_lexer','mixed_case','yes');
ctx_ddl.create_preference('japanese_lexer', 'JAPANESE_VGRAM_LEXER');
After the language-specific lexer preferences are created, they need to be gathered
together under a single multilexer preference. First, create the multilexer preference,
using the MULTI_LEXER object:
ctx_ddl.create_preference('global_lexer','multi_lexer');
Now add the language-specific lexers to the multilexer preference using the add_
sub_lexer call:
Table 6–7 Comparison of LOB Datatypes for Document Storage
Datatypes Advantages Disadvantages
CLOB ■Content search support
■String manipulation support
■Depends on database character set
■Data conversion is necessary for
insertion
■Cannot store binary documents
NCLOB ■Independent of database character set
■String manipulation support
■No content search support
■Data conversion is necessary for
insertion
■Cannot store binary documents
BLOB ■Independent of database character set
■Content search support
■No data conversion, data stored as is
■Can store binary documents such as Microsoft
Word or Microsoft Excel
■No string manipulation support
See Also: Oracle Text Reference
Designing Database Schemas to Support Multiple Languages
Supporting Multilingual Databases with Unicode 6-17
ctx_ddl.add_sub_lexer('global_lexer', 'german', 'german_lexer');
ctx_ddl.add_sub_lexer('global_lexer', 'japanese', 'japanese_lexer');
ctx_ddl.add_sub_lexer('global_lexer', 'default','english_lexer');
This nominates the german_lexer preference to handle German documents, the
japanese_lexer preference to handle Japanese documents, and the english_
lexer preference to handle everything else, using DEFAULT as the language.
Creating Indexes for Documents Stored in the CLOB Datatype
The multilexer decides which lexer to use for each row based on a language column in
the table. This is a character column that stores the language of the document in a text
column. Use the Oracle language name to identify the language of a document in this
column. For example, if you use the CLOB datatype to store your documents, then add
the language column to the table where the documents are stored:
CREATE TABLE globaldoc
(doc_id NUMBER PRIMARY KEY,
language VARCHAR2(30),
text CLOB);
To create an index for this table, use the multilexer preference and specify the name of
the language column:
CREATE INDEX globalx ON globaldoc(text)
indextype IS ctxsys.context
parameters ('lexer
global_lexer
language
column
language');
Creating Indexes for Documents Stored in the BLOB Datatype
In addition to the language column, the character set and format columns must be
added in the table where the documents are stored. The character set column stores the
character set of the documents using the Oracle character set names. The format
column specifies whether a document is a text or binary document. For example, the
CREATE TABLE statement can specify columns called characterset and format:
CREATE TABLE globaldoc (
doc_id NUMBER PRIMARY KEY,
language VARCHAR2(30),
characterset VARCHAR2(30),
format VARCHAR2(10),
text BLOB
);
You can put word-processing or spreadsheet documents into the table and specify
binary in the format column. For documents in HTML, XML and text format, you
can put them into the table and specify text in the format column.
Because there is a column in which to specify the character set, you can store text
documents in different character sets.
When you create the index, specify the names of the format and character set columns:
CREATE INDEX globalx ON globaldoc(text)
indextype is ctxsys.context
parameters ('filter inso_filter
lexer global_lexer
language column language
Designing Database Schemas to Support Multiple Languages
6-18 Oracle Database Globalization Support Guide
format column format
charset column characterset');
You can use the charset_filter if all documents are in text format. The charset_
filter converts data from the character set specified in the charset column to the
database character set.
Programming with Unicode 7-1
7
Programming with Unicode
This chapter describes how to use programming and access products for Oracle
Database with Unicode. This chapter contains the following topics:
■Overview of Programming with Unicode
■SQL and PL/SQL Programming with Unicode
■OCI Programming with Unicode
■Pro*C/C++ Programming with Unicode
■JDBC Programming with Unicode
■ODBC and OLE DB Programming with Unicode
■XML Programming with Unicode
Overview of Programming with Unicode
Oracle offers several database access products for inserting and retrieving Unicode
data. Oracle offers database access products for commonly used programming
environments such as Java and C/C++. Data is transparently converted between the
database and client programs, which ensures that client programs are independent of
the database character set and national character set. In addition, client programs are
sometimes even independent of the character datatype, such as NCHAR or CHAR, used
in the database.
To avoid overloading the database server with data conversion operations, Oracle
always tries to move them to the client side database access products. In a few cases,
data must be converted in the database, which affects performance. This chapter
discusses details of the data conversion paths.
Database Access Product Stack and Unicode
Oracle offers a comprehensive set of database access products that enable programs
from different development environments to access Unicode data stored in the
database. These products are listed in Table 7–1.
Overview of Programming with Unicode
7-2 Oracle Database Globalization Support Guide
Figure 7–1 shows how the database access products can access the database.
Figure 7–1 Oracle Database Access Products
The Oracle Call Interface (OCI) is the lowest level API that the rest of the client-side
database access products use. It provides a flexible way for C/C++ programs to access
Unicode data stored in SQL CHAR and NCHAR datatypes. Using OCI, you can
programmatically specify the character set (UTF-8, UTF-16, and others) for the data to
be inserted or retrieved. It accesses the database through Oracle Net.
Oracle Pro*C/C++ enables you to embed SQL and PL/SQL in your programs. It uses
OCI's Unicode capabilities to provide UTF-16 and UTF-8 data access for SQL CHAR
and NCHAR datatypes.
The Oracle ODBC driver enables C/C++, Visual Basic, and VBScript programs
running on Windows platforms to access Unicode data stored in SQL CHAR and NCHAR
datatypes of the database. It provides UTF-16 data access by implementing the
SQLWCHAR interface specified in the ODBC standard specification.
The Oracle Provider for OLE DB enables C/C++, Visual Basic, and VBScript programs
running on Windows platforms to access Unicode data stored in SQL CHAR and NCHAR
datatypes. It provides UTF-16 data access through wide string OLE DB datatypes.
Table 7–1 Oracle Database Access Products
Programming
Environment Oracle Database Access Products
C/C++ Oracle Call Interface (OCI)
Oracle Pro*C/C++
Oracle ODBC driver
Oracle Provider for OLE DB
Oracle Data Provider for .NET
Java Oracle JDBC OCI or thin driver
Oracle server-side thin driver
Oracle server-side internal driver
PL/SQL Oracle PL/SQL and SQL
Visual Basic/C# Oracle ODBC driver
Oracle Provider for OLE DB
· Visual Basic Programs
· VBScript using ADO
· C#
· ASP
C/C++ Programs
· OLE DB
· ODBC
· Oracle Data Provider
for .NET
Pro*C/C++
JDBC
Oracle Call Interface (OCI) Thin
Oracle
PL/SQL
SQL
Java
Oracle
Net
Oracle Net on TCP/IP
Java Programs
SQL and PL/SQL Programming with Unicode
Programming with Unicode 7-3
The Oracle Data Provider for .NET enables programs running in any .NET
programming environment on Windows platforms to access Unicode data stored in
SQL CHAR and NCHAR datatypes. It provides UTF-16 data access through Unicode
datatypes.
Oracle JDBC drivers are the primary Java programmatic interface for accessing an
Oracle database. Oracle provides the following JDBC drivers:
■The JDBC OCI driver that is used by Java applications and requires the OCI
library
■The JDBC thin driver, which is a pure Java driver that is primarily used by Java
applets and supports the Oracle Net protocol over TCP/IP
■The JDBC server-side thin driver, a pure Java driver used inside Java stored
procedures to connect to another Oracle server
■The JDBC server-side internal driver that is used inside the Oracle server to access
the data in the database
All drivers support Unicode data access to SQL CHAR and NCHAR datatypes in the
database.
The PL/SQL and SQL engines process PL/SQL programs and SQL statements on
behalf of client-side programs such as OCI and server-side PL/SQL stored procedures.
They allow PL/SQL programs to declare CHAR, VARCHAR2, NCHAR, and NVARCHAR2
variables and to access SQL CHAR and NCHAR datatypes in the database.
The following sections describe how each of the database access products supports
Unicode data access to an Oracle database and offer examples for using those
products:
■SQL and PL/SQL Programming with Unicode
■OCI Programming with Unicode
■Pro*C/C++ Programming with Unicode
■JDBC Programming with Unicode
■ODBC and OLE DB Programming with Unicode
SQL and PL/SQL Programming with Unicode
SQL is the fundamental language with which all programs and users access data in an
Oracle database either directly or indirectly. PL/SQL is a procedural language that
combines the data manipulating power of SQL with the data processing power of
procedural languages. Both SQL and PL/SQL can be embedded in other programming
languages. This section describes Unicode-related features in SQL and PL/SQL that
you can deploy for multilingual applications.
This section contains the following topics:
■SQL NCHAR Datatypes
■Implicit Datatype Conversion Between NCHAR and Other Datatypes
■Exception Handling for Data Loss During Datatype Conversion
■Rules for Implicit Datatype Conversion
■SQL Functions for Unicode Datatypes
■Other SQL Functions
SQL and PL/SQL Programming with Unicode
7-4 Oracle Database Globalization Support Guide
■Unicode String Literals
■Using the UTL_FILE Package with NCHAR Data
SQL NCHAR Datatypes
There are three SQL NCHAR datatypes:
■The NCHAR Datatype
■The NVARCHAR2 Datatype
■The NCLOB Datatype
The NCHAR Datatype
When you define a table column or a PL/SQL variable as the NCHAR datatype, the
length is always specified as the number of characters. For example, the following
statement creates a column with a maximum length of 30 characters:
CREATE TABLE table1 (column1 NCHAR(30));
The maximum number of bytes for the column is determined as follows:
maximum number of bytes = (maximum number of characters) x (maximum number of
bytes for each character)
For example, if the national character set is UTF8, then the maximum byte length is 30
characters times 3 bytes for each character, or 90 bytes.
The national character set, which is used for all NCHAR datatypes, is defined when the
database is created. The national character set can be either UTF8 or AL16UTF16. The
default is AL16UTF16.
The maximum column size allowed is 2000 characters when the national character set
is UTF8 and 1000 when it is AL16UTF16. The actual data is subject to the maximum
byte limit of 2000. The two size constraints must be satisfied at the same time. In
PL/SQL, the maximum length of NCHAR data is 32767 bytes. You can define an NCHAR
variable of up to 32767 characters, but the actual data cannot exceed 32767 bytes. If
you insert a value that is shorter than the column length, then Oracle pads the value
with blanks to whichever length is smaller: maximum character length or maximum
byte length.
The NVARCHAR2 Datatype
The NVARCHAR2 datatype specifies a variable length character string that uses the
national character set. When you create a table with an NVARCHAR2 column, you
specify the maximum number of characters for the column. Lengths for NVARCHAR2
are always in units of characters, just as for NCHAR. Oracle subsequently stores each
See Also:
■Oracle Database SQL Reference
■PL/SQL User's Guide and Reference
Note: UTF8 may affect performance because it is a variable-width
character set. Excessive blank padding of NCHAR fields decreases
performance. Consider using the NVARCHAR datatype or changing
to the AL16UTF16 character set for the NCHAR datatype.
SQL and PL/SQL Programming with Unicode
Programming with Unicode 7-5
value in the column exactly as you specify it, if the value does not exceed the column's
maximum length. Oracle does not pad the string value to the maximum length.
The maximum column size allowed is 4000 characters when the national character set
is UTF8 and 2000 when it is AL16UTF16. The maximum length of an NVARCHAR2
column in bytes is 4000. Both the byte limit and the character limit must be met, so the
maximum number of characters that is actually allowed in an NVARCHAR2 column is
the number of characters that can be written in 4000 bytes.
In PL/SQL, the maximum length for an NVARCHAR2 variable is 32767 bytes. You can
define NVARCHAR2 variables up to 32767 characters, but the actual data cannot exceed
32767 bytes.
The following statement creates a table with one NVARCHAR2 column whose
maximum length in characters is 2000 and maximum length in bytes is 4000.
CREATE TABLE table2 (column2 NVARCHAR2(2000));
The NCLOB Datatype
NCLOB is a character large object containing Unicode characters, with a maximum size
of 4 gigabytes. Unlike the BLOB datatype, the NCLOB datatype has full transactional
support so that changes made through SQL, the DBMS_LOB package, or OCI
participate fully in transactions. Manipulations of NCLOB value can be committed and
rolled back. Note, however, that you cannot save an NCLOB locator in a PL/SQL or
OCI variable in one transaction and then use it in another transaction or session.
NCLOB values are stored in the database in a format that is compatible with UCS-2,
regardless of the national character set. Oracle translates the stored Unicode value to
the character set requested on the client or on the server, which can be fixed-width or
variable-width. When you insert data into an NCLOB column using a variable-width
character set, Oracle converts the data into a format that is compatible with UCS-2
before storing it in the database.
Implicit Datatype Conversion Between NCHAR and Other Datatypes
Oracle supports implicit conversions between SQL NCHAR datatypes and other Oracle
datatypes, such as CHAR, VARCHAR2, NUMBER, DATE, ROWID, and CLOB. Any implicit
conversions for CHAR and VARCHAR2 datatypes are also supported for SQL NCHAR
datatypes. You can use SQL NCHAR datatypes the same way as SQL CHAR datatypes.
Type conversions between SQL CHAR datatypes and SQL NCHAR datatypes may
involve character set conversion when the database and national character sets are
different. Padding with blanks may occur if the target data is either CHAR or NCHAR.
Exception Handling for Data Loss During Datatype Conversion
Data loss can occur during datatype conversion when character set conversion is
necessary. If a character in the source character set is not defined in the target character
set, then a replacement character is used in its place. For example, if you try to insert
NCHAR data into a regular CHAR column and the character data in NCHAR (Unicode)
form cannot be converted to the database character set, then the character is replaced
by a replacement character defined by the database character set. The NLS_NCHAR_
CONV_EXCP initialization parameter controls the behavior of data loss during
See Also: Oracle Database Application Developer's Guide - Large
Objects for more information about the NCLOB datatype
See Also: Oracle Database SQL Reference
SQL and PL/SQL Programming with Unicode
7-6 Oracle Database Globalization Support Guide
character type conversion. When this parameter is set to TRUE, any SQL statements
that result in data loss return an ORA-12713 error and the corresponding operation is
stopped. When this parameter is set to FALSE, data loss is not reported and the
unconvertible characters are replaced with replacement characters. The default value
is TRUE. This parameter works for both implicit and explicit conversion.
In PL/SQL, when data loss occurs during conversion of SQL CHAR and NCHAR
datatypes, the LOSSY_CHARSET_CONVERSION exception is raised for both implicit
and explicit conversion.
Rules for Implicit Datatype Conversion
In some cases, conversion between datatypes is possible in only one direction. In other
cases, conversion in both directions is possible. Oracle defines a set of rules for
conversion between datatypes. Table 7–2 contains the rules for conversion between
datatypes.
Table 7–2 Rules for Conversion Between Datatypes
Statement Rule
INSERT/UPDATE
statement Values are converted to the datatype of the target database column.
SELECT INTO statement Data from the database is converted to the datatype of the target variable.
Variable assignments Values on the right of the equal sign are converted to the datatype of the target variable
on the left of the equal sign.
Parameters in SQL and
PL/SQL functions CHAR, VARCHAR2, NCHAR, and NVARCHAR2 are loaded the same way. An argument with
a CHAR, VARCHAR2, NCHAR or NVARCHAR2 datatype is compared to a formal parameter
of any of the CHAR, VARCHAR2, NCHAR or NVARCHAR2 datatypes. If the argument and
formal parameter datatypes do not match exactly, then implicit conversions are
introduced when data is copied into the parameter on function entry and copied out to
the argument on function exit.
Concatenation ||
operation or CONCAT
function
If one operand is a SQL CHAR or NCHAR datatype and the other operand is a NUMBER or
other non-character datatype, then the other datatype is converted to VARCHAR2 or
NVARCHAR2. For concatenation between character datatypes, see "SQL NCHAR datatypes
and SQL CHAR datatypes" on page 7-7.
SQL CHAR or NCHAR
datatypes and NUMBER
datatype
Character values are converted to NUMBER datatype.
SQL and PL/SQL Programming with Unicode
Programming with Unicode 7-7
SQL Functions for Unicode Datatypes
SQL NCHAR datatypes can be converted to and from SQL CHAR datatypes and other
datatypes using explicit conversion functions. The examples in this section use the
table created by the following statement:
CREATE TABLE customers
(id NUMBER, name NVARCHAR2(50), address NVARCHAR2(200), birthdate DATE);
Example 7–1 Populating the Customers Table Using the TO_NCHAR Function
The TO_NCHAR function converts the data at run time, while the N function converts
the data at compilation time.
INSERT INTO customers VALUES (1000,
TO_NCHAR('John Smith'),N'500 Oracle Parkway',sysdate);
Example 7–2 Selecting from the Customer Table Using the TO_CHAR Function
The following statement converts the values of name from characters in the national
character set to characters in the database character set before selecting them according
to the LIKE clause:
SELECT name FROM customers WHERE TO_CHAR(name) LIKE '%Sm%';
You should see the following output:
NAME
--------------------------------------
John Smith
Example 7–3 Selecting from the Customer Table Using the TO_DATE Function
Using the N function shows that either NCHAR or CHAR data can be passed as
parameters for the TO_DATE function. The datatypes can mixed because they are
converted at run time.
SQL CHAR or NCHAR
datatypes and DATE
datatype
Character values are converted to DATE datatype.
SQL CHAR or NCHAR
datatypes and ROWID
datatype
Character values are converted to ROWID datatype.
SQL NCHAR datatypes
and SQL CHAR
datatypes
Comparisons between SQL NCHAR datatypes and SQL CHAR datatypes are more
complex because they can be encoded in different character sets.
When CHAR and VARCHAR2 values are compared, the CHAR values are converted to
VARCHAR2 values.
When NCHAR and NVARCHAR2 values are compared, the NCHAR values are converted to
NVARCHAR2 values.
When there is comparison between SQL NCHAR datatypes and SQL CHAR datatypes,
character set conversion occurs if they are encoded in different character sets. The
character set for SQL NCHAR datatypes is always Unicode and can be either UTF8 or
AL16UTF16 encoding, which have the same character repertoires but are different
encodings of the Unicode standard. SQL CHAR datatypes use the database character set,
which can be any character set that Oracle supports. Unicode is a superset of any
character set supported by Oracle, so SQL CHAR datatypes can always be converted to
SQL NCHAR datatypes without data loss.
Table 7–2 (Cont.) Rules for Conversion Between Datatypes
Statement Rule
SQL and PL/SQL Programming with Unicode
7-8 Oracle Database Globalization Support Guide
DECLARE
ndatestring NVARCHAR2(20) := N'12-SEP-1975';
ndstr NVARCHAR2(50);
BEGIN
SELECT name INTO ndstr FROM customers
WHERE (birthdate)> TO_DATE(ndatestring, 'DD-MON-YYYY', N'NLS_DATE_LANGUAGE =
AMERICAN');
END;
As demonstrated in Example 7–3, SQL NCHAR data can be passed to explicit
conversion functions. SQL CHAR and NCHAR data can be mixed together when using
multiple string parameters.
Other SQL Functions
Most SQL functions can take arguments of SQL NCHAR datatypes as well as mixed
character datatypes. The return datatype is based on the type of the first argument. If a
non-string datatype like NUMBER or DATE is passed to these functions, then it is
converted to VARCHAR2. The following examples use the customer table created in
"SQL Functions for Unicode Datatypes" on page 7-7.
Example 7–4 INSTR Function
In this example, the string literal 'Sm' is converted to NVARCHAR2 and then scanned
by INSTR, to detect the position of the first occurrence of this string in name.
SELECT INSTR(name, N'Sm', 1, 1) FROM customers;
Example 7–5 CONCAT Function
SELECT CONCAT(name,id) FROM customers;
id is converted to NVARCHAR2 and then concatenated with name.
Example 7–6 RPAD Function
SELECT RPAD(name,100,' ') FROM customers;
The following output results:
RPAD(NAME,100,'')
------------------------------------------
John Smith
The space character ' ' is converted to the corresponding character in the NCHAR
character set and then padded to the right of name until the total display length
reaches 100.
Unicode String Literals
You can input Unicode string literals in SQL and PL/SQL as follows:
■Put a prefix N before a string literal that is enclosed with single quote marks. This
explicitly indicates that the following string literal is an NCHAR string literal. For
See Also: Oracle Database SQL Reference for more information
about explicit conversion functions for SQL NCHAR datatypes
See Also: Oracle Database SQL Reference
SQL and PL/SQL Programming with Unicode
Programming with Unicode 7-9
example, N'résumé' is an NCHAR string literal. For information about limitations
of this method, see NCHAR String Literal Replacement on page 7-9.
■Use the NCHR(n) SQL function, which returns a unit of character code in the
national character set, which is AL16UTF16 or UTF8. The result of concatenating
several NCHR(n) functions is NVARCHAR2 data. In this way, you can bypass the
client and server character set conversions and create an NVARCHAR2 string
directly. For example, NCHR(32) represents a blank character.
Because NCHR(n) is associated with the national character set, portability of the
resulting value is limited to applications that run with the same national character
set. If this is a concern, then use the UNISTR function to remove portability
limitations.
■Use the UNISTR('string') SQL function. UNISTR('string') converts a string to
the national character set. To ensure portability and to preserve data, include only
ASCII characters and Unicode encoding in the following form: \xxxx, where
xxxx is the hexadecimal value of a character code value in UTF-16 encoding
format. For example, UNISTR('G\0061ry') represents 'Gary'. The ASCII
characters are converted to the database character set and then to the national
character set. The Unicode encoding is converted directly to the national character
set.
The last two methods can be used to encode any Unicode string literals.
NCHAR String Literal Replacement
This section provides information on how to avoid data loss when performing NCHAR
string literal replacement.
Being part of a SQL or PL/SQL statement, the text of any literal, with or without the
prefix N, is encoded in the same character set as the rest of the statement. On the client
side, the statement is in the client character set, which is determined by the client
character set defined in NLS_LANG, or specified in the OCIEnvNlsCreate() call, or
predefined as UTF-16 in JDBC. On the server side the statement is in the database
character set.
■When the SQL or PL/SQL statement is transferred from client to the database
server, its character set is converted accordingly. It is important to note that if the
database character set does not contain all characters used in the text literals, then
the data is lost in this conversion. This problem affects NCHAR string literals more
than the CHAR text literals. This is because the N' literals are designed to be
independent of the database charactser set, and should be able to provide any data
that the client character set supports.
To avoid data loss in conversion to an incompatible database character set, you can
activate the NCHAR literal replacement functionality. The functionality
transparently replaces the N' literals on the client side with an internal format. The
database server then decodes this to Unicode when the statement is executed.
■The sections "Handling SQL NCHAR String Literals in OCI" on page 7-16 and
"Using SQL NCHAR String Literals in JDBC" on page 7-22 show how to switch on
the replacement functionality in OCI and JDBC, respectively. Because many
applications, for example, SQL*Plus, use OCI to connect to a database, and they do
not control NCHAR literal replacement explicitly, you can set the client environment
variable ORA_NCHAR_LITERAL_REPLACE to TRUE to control the functionality for
them. By default, the functionality is switched off to maintain backward
compatibility.
OCI Programming with Unicode
7-10 Oracle Database Globalization Support Guide
Using the UTL_FILE Package with NCHAR Data
The UTL_FILE package handles Unicode national character set data. The functions
and procedures include the following:
■FOPEN_NCHAR
This function opens a file in Unicode for input or output, with the maximum line
size specified. With this function, you can read or write a text file in Unicode
instead of in the database character set.
■GET_LINE_NCHAR
This procedure reads text from the open file identified by the file handle and
places the text in the output buffer parameter. With this procedure, you can read a
text file in Unicode instead of in the database character set.
■PUT_NCHAR
This procedure writes the text string stored in the buffer parameter to the open file
identified by the file handle. With this procedure, you can write a text file in
Unicode instead of in the database character set.
■PUT_LINE_NCHAR
This procedure writes the text string stored in the buffer parameter to the open file
identified by the file handle. With this procedure, you can write a text file in
Unicode instead of in the database character set.
■PUTF_NCHAR
This procedure is a formatted PUT_NCHAR procedure. With this procedure, you
can write a text file in Unicode instead of in the database character set.
OCI Programming with Unicode
OCI is the lowest-level API for accessing a database, so it offers the best possible
performance. When using Unicode with OCI, consider these topics:
■OCIEnvNlsCreate() Function for Unicode Programming
■OCI Unicode Code Conversion
■Setting UTF-8 to the NLS_LANG Character Set in OCI
■Binding and Defining SQL CHAR Datatypes in OCI
■Binding and Defining SQL NCHAR Datatypes in OCI
■Binding and Defining CLOB and NCLOB Unicode Data in OCI
OCIEnvNlsCreate() Function for Unicode Programming
The OCIEnvNlsCreate() function is used to specify a SQL CHAR character set and a
SQL NCHAR character set when the OCI environment is created. It is an enhanced
version of the OCIEnvCreate() function and has extended arguments for two
character set IDs. The OCI_UTF16ID UTF-16 character set ID replaces the Unicode
mode introduced in Oracle9i release 1 (9.0.1). For example:
See Also: PL/SQL Packages and Types Reference for more
information about the UTL_FILE package
See Also: Chapter 10, "OCI Programming in a Global
Environment"
OCI Programming with Unicode
Programming with Unicode 7-11
OCIEnv *envhp;
status = OCIEnvNlsCreate((OCIEnv **)&envhp,
(ub4)0,
(void *)0,
(void *(*) ()) 0,
(void *(*) ()) 0,
(void(*) ()) 0,
(size_t) 0,
(void **)0,
(ub2)OCI_UTF16ID, /* Metadata and SQL CHAR character set */
(ub2)OCI_UTF16ID /* SQL NCHAR character set */);
The Unicode mode, in which the OCI_UTF16 flag is used with the OCIEnvCreate()
function, is deprecated.
When OCI_UTF16ID is specified for both SQL CHAR and SQL NCHAR character sets, all
metadata and bound and defined data are encoded in UTF-16. Metadata includes SQL
statements, user names, error messages, and column names. Thus, all inherited
operations are independent of the NLS_LANG setting, and all metatext data parameters
(text*) are assumed to be Unicode text datatypes (utext*) in UTF-16 encoding.
To prepare the SQL statement when the OCIEnv() function is initialized with the
OCI_UTF16ID character set ID, call the OCIStmtPrepare() function with a
(utext*) string. The following example runs on the Windows platform only. You
may need to change wchar_t datatypes for other platforms.
const wchar_t sqlstr[] = L"SELECT * FROM ENAME=:ename";
...
OCIStmt* stmthp;
sts = OCIHandleAlloc(envh, (void **)&stmthp, OCI_HTYPE_STMT, 0,
NULL);
status = OCIStmtPrepare(stmthp, errhp,(const text*)sqlstr,
wcslen(sqlstr), OCI_NTV_SYNTAX, OCI_DEFAULT);
To bind and define data, you do not have to set the OCI_ATTR_CHARSET_ID attribute
because the OCIEnv() function has already been initialized with UTF-16 character set
IDs. The bind variable names also must be UTF-16 strings.
/* Inserting Unicode data */
OCIBindByName(stmthp1, &bnd1p, errhp, (const text*)L":ename",
(sb4)wcslen(L":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 *)
&ename_col_len,
(ub4) 0, (ub4)OCI_ATTR_MAXDATA_SIZE, errhp);
...
/* Retrieving Unicode data */
OCIDefineByPos (stmthp2, &dfn1p, errhp, (ub4)1, (void *)ename,
(sb4)sizeof(ename), SQLT_STR, (void *)0, (ub2 *)0,
(ub2*)0, (ub4)OCI_DEFAULT);
The OCIExecute() function performs the operation.
See Also: "Specifying Character Sets in OCI" on page 10-2
OCI Programming with Unicode
7-12 Oracle Database Globalization Support Guide
OCI Unicode Code Conversion
Unicode character set conversions take place between an OCI client and the database
server if the client and server character sets are different. The conversion occurs on
either the client or the server depending on the circumstances, but usually on the client
side.
Data Integrity
You can lose data during conversion if you call an OCI API inappropriately. If the
server and client character sets are different, then you can lose data when the
destination character set is a smaller set than the source character set. You can avoid
this potential problem if both character sets are Unicode character sets (for example,
UTF8 and AL16UTF16).
When you bind or define SQL NCHAR datatypes, you should set the OCI_ATTR_
CHARSET_FORM attribute to SQLCS_NCHAR. Otherwise, you can lose data because the
data is converted to the database character set before converting to or from the
national character set. This occurs only if the database character set is not Unicode.
OCI Performance Implications When Using Unicode
Redundant data conversions can cause performance degradation in your OCI
applications. These conversions occur in two cases:
■When you bind or define SQL CHAR datatypes and set the OCI_ATTR_CHARSET_
FORM attribute to SQLCS_NCHAR, data conversions take place from client character
set to the national database character set, and from the national character set to the
database character set. No data loss is expected, but two conversions happen, even
though it requires only one.
■When you bind or define SQL NCHAR datatypes and do not set OCI_ATTR_
CHARSET_FORM, data conversions take place from client character set to the
database character set, and from the database character set to the national database
character set. In the worst case, data loss can occur if the database character set is
smaller than the client's.
To avoid performance problems, you should always set OCI_ATTR_CHARSET_FORM
correctly, based on the datatype of the target columns. If you do not know the target
datatype, then you should set the OCI_ATTR_CHARSET_FORM attribute to SQLCS_
NCHAR when binding and defining.
Table 7–3 contains information about OCI character set conversions.
OCI Programming with Unicode
Programming with Unicode 7-13
OCI Unicode Data Expansion
Data conversion can result in data expansion, which can cause a buffer to overflow.
For binding operations, you need to set the OCI_ATTR_MAXDATA_SIZE attribute to a
large enough size to hold the expanded data on the server. If this is difficult to do, then
you need to consider changing the table schema. For defining operations, client
applications need to allocate enough buffer space for the expanded data. The size of
the buffer should be the maximum length of the expanded data. You can estimate the
maximum buffer length with the following calculation:
1. Get the column data byte size.
2. Multiply it by the maximum number of bytes for each character in the client
character set.
Table 7–3 OCI Character Set Conversions
Datatypes for
OCI Client Buffer
OCI_ATTR_
CHARSET_
FORM
Datatypes of the
Target Column in
the Database Conversion Between Comments
utext SQLCS_
IMPLICIT
CHAR,
VARCHAR2,
CLOB
UTF-16 and database
character set in OCI No unexpected data loss
utext SQLCS_
NCHAR
NCHAR,
NVARCHAR2,
NCLOB
UTF-16 and national
character set in OCI No unexpected data loss
utext SQLCS_
NCHAR
CHAR,
VARCHAR2,
CLOB
UTF-16 and national
character set in OCI
National character set and
database character set in
database server
No unexpected data loss,
but may degrade
performance because the
conversion goes through the
national character set
utext SQLCS_
IMPLICIT
NCHAR,
NVARCHAR2,
NCLOB
UTF-16 and database
character set in OCI
Database character set and
national character set in
database server
Data loss may occur if the
database character set is not
Unicode
text SQLCS_
IMPLICIT
CHAR,
VARCHAR2,
CLOB
NLS_LANG character set
and database character set
in OCI
No unexpected data loss
text SQLCS_
NCHAR
NCHAR,
NVARCHAR2,NCLOB
NLS_LANG character set
and national character set
in OCI
No unexpected data loss
text SQLCS_
NCHAR
CHAR,
VARCHAR2,
CLOB
NLS_LANG character set
and national character set
in OCI
National character set and
database character set in
database server
No unexpected data loss,
but may degrade
performance because the
conversion goes through the
national character set
text SQLCS_
IMPLICIT
NCHAR,
NVARCHAR2,NCLOB
NLS_LANG character set
and database character set
in OCI
Database character set and
national character set in
database server
Data loss may occur because
the conversion goes through
the database character set
OCI Programming with Unicode
7-14 Oracle Database Globalization Support Guide
This method is the simplest and quickest way, but it may not be accurate and can
waste memory. It is applicable to any character set combination. For example, for
UTF-16 data binding and defining, the following example calculates the client buffer:
ub2 csid = OCI_UTF16ID;
oratext *selstmt = "SELECT ename FROM emp";
counter = 1;
...
OCIStmtPrepare(stmthp, errhp, selstmt, (ub4)strlen((char*)selstmt),
OCI_NTV_SYNTAX, OCI_DEFAULT);
OCIStmtExecute ( svchp, stmthp, errhp, (ub4)0, (ub4)0,
(CONST OCISnapshot*)0, (OCISnapshot*)0,
OCI_DESCRIBE_ONLY);
OCIParamGet(stmthp, OCI_HTYPE_STMT, errhp, &myparam, (ub4)counter);
OCIAttrGet((void*)myparam, (ub4)OCI_DTYPE_PARAM, (void*)&col_width,
(ub4*)0, (ub4)OCI_ATTR_DATA_SIZE, errhp);
...
maxenamelen = (col_width + 1) * sizeof(utext);
cbuf = (utext*)malloc(maxenamelen);
...
OCIDefineByPos(stmthp, &dfnp, errhp, (ub4)1, (void *)cbuf,
(sb4)maxenamelen, SQLT_STR, (void *)0, (ub2 *)0,
(ub2*)0, (ub4)OCI_DEFAULT);
OCIAttrSet((void *) dfnp, (ub4) OCI_HTYPE_DEFINE, (void *) &csid,
(ub4) 0, (ub4)OCI_ATTR_CHARSET_ID, errhp);
OCIStmtFetch(stmthp, errhp, 1, OCI_FETCH_NEXT, OCI_DEFAULT);
...
Setting UTF-8 to the NLS_LANG Character Set in OCI
For OCI client applications that support Unicode UTF-8 encoding, use AL32UTF8 to
specify the NLS_LANG character set, unless the database character set is UTF8. Use
UTF8 if the database character set is UTF8.
Do not set NLS_LANG to AL16UTF16, because AL16UTF16 is the national character set
for the server. If you need to use UTF-16, then you should specify the client character
set to OCI_UTF16ID, using the OCIAttrSet() function when binding or defining
data
Binding and Defining SQL CHAR Datatypes in OCI
To specify a Unicode character set for binding and defining data with SQL CHAR
datatypes, you may need to call the OCIAttrSet() function to set the appropriate
character set ID after OCIBind() or OCIDefine() APIs. There are two typical cases:
■Call OCIBind() or OCIDefine() followed by OCIAttrSet() to specify UTF-16
Unicode character set encoding. For example:
...
ub2 csid = OCI_UTF16ID;
utext ename[100]; /* enough buffer for ENAME */
...
/* Inserting Unicode data */
OCIBindByName(stmthp1, &bnd1p, errhp, (oratext*)":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,
OCI Programming with Unicode
Programming with Unicode 7-15
(ub4) 0, (ub4)OCI_ATTR_MAXDATA_SIZE, errhp);
...
/* Retrieving Unicode data */
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);
...
If bound buffers are of the utext datatype, then you should add a cast (text*)
when OCIBind() or OCIDefine() is called. The value of the OCI_ATTR_
MAXDATA_SIZE attribute is usually determined by the column size of the server
character set because this size is only used to allocate temporary buffer space for
conversion on the server when you perform binding operations.
■Call OCIBind() or OCIDefine() with the NLS_LANG character set specified as
UTF8 or AL32UTF8.
UTF8 or AL32UTF8 can be set in the NLS_LANG environment variable. You call
OCIBind() and OCIDefine() in exactly the same manner as when you are not
using Unicode. Set the NLS_LANG environment variable to UTF8 or AL32UTF8
and run the following OCI program:
...
oratext ename[100]; /* enough buffer size for ENAME */
...
/* Inserting Unicode data */
OCIBindByName(stmthp1, &bnd1p, errhp, (oratext*)":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 *) &ename_col_len,
(ub4) 0, (ub4)OCI_ATTR_MAXDATA_SIZE, errhp);
...
/* Retrieving Unicode data */
OCIDefineByPos (stmthp2, &dfn1p, errhp, (ub4)1, (void *)ename,
(sb4)sizeof(ename), SQLT_STR, (void *)0, (ub2 *)0, (ub2*)0,
(ub4)OCI_DEFAULT);
...
Binding and Defining SQL NCHAR Datatypes in OCI
Oracle recommends that you access SQL NCHAR datatypes using UTF-16 binding or
defining when using OCI. Beginning with Oracle9i, SQL NCHAR datatypes are Unicode
datatypes with an encoding of either UTF8 or AL16UTF16. To access data in SQL
NCHAR datatypes, set the OCI_ATTR_CHARSET_FORM attribute to SQLCS_NCHAR
between binding or defining and execution so that it performs an appropriate data
conversion without data loss. The length of data in SQL NCHAR datatypes is always in
the number of Unicode code units.
The following program is a typical example of inserting and fetching data against an
NCHAR data column:
...
ub2 csid = OCI_UTF16ID;
ub1 cform = SQLCS_NCHAR;
utext ename[100]; /* enough buffer for ENAME */
...
/* Inserting Unicode data */
OCI Programming with Unicode
7-16 Oracle Database Globalization Support Guide
OCIBindByName(stmthp1, &bnd1p, errhp, (oratext*)":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 *) &cform, (ub4) 0,
(ub4)OCI_ATTR_CHARSET_FORM, errhp);
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 Unicode data */
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);
OCIAttrSet((void *) dfn1p, (ub4) OCI_HTYPE_DEFINE, (void *) &cform, (ub4) 0,
(ub4)OCI_ATTR_CHARSET_FORM, errhp);
...
Handling SQL NCHAR String Literals in OCI
By default, the NCHAR literal replacement is not performed in OCI. (Refer to "NCHAR
String Literal Replacement" on page 7-9.)
You can switch it on by setting the environment variable ORA_NCHAR_LITERAL_
REPLACE to TRUE. You can also achieve this behavior programmatically by using the
OCI_NCHAR_LITERAL_REPLACE_ON and OCI_NCHAR_LITERAL_REPLACE_OFF
modes in OCIEnvCreate() and OCIEnvNlsCreate(). So, for example,
OCIEnvCreate(OCI_NCHAR_LITERAL_REPLACE_ON) turns on NCHAR literal
replacement, while OCIEnvCreate(OCI_NCHAR_LITERAL_REPLACE_OFF) turns it
off.
As an example, consider the following statement:
int main(argc, argv)
{
OCIEnv *envhp;
if (OCIEnvCreate((OCIEnv **) &envhp,
(ub4)OCI_THREADED|OCI_NCHAR_LITERAL_REPLACE_ON,
(dvoid *)0, (dvoid * (*)(dvoid *, size_t)) 0,
(dvoid * (*)(dvoid *, dvoid *, size_t))0,
(void (*)(dvoid *, dvoid *)) 0,
(size_t) 0, (dvoid **) 0))
{
printf("FAILED: OCIEnvCreate()\n";
return 1;
}
...
}
Note that, when the NCHAR literal replacement is turned on, OCIStmtPrepare and
OCIStmtPrepare2 will transform N' literals with U' literals in the SQL text and
store 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 SQL
text will return U' instead of N' as specified in the original text.
See the Oracle Database SQL Reference for information regarding environment variables.
Pro*C/C++ Programming with Unicode
Programming with Unicode 7-17
Binding and Defining CLOB and NCLOB Unicode Data in OCI
In order to write (bind) and read (define) UTF-16 data for CLOB or NCLOB columns, the
UTF-16 character set ID must be specified as OCILobWrite() and OCILobRead().
When you write UTF-16 data into a CLOB column, call OCILobWrite() as follows:
...
ub2 csid = OCI_UTF16ID;
err = OCILobWrite (ctx->svchp, ctx->errhp, lobp, &amtp, offset, (void *) buf,
(ub4) BUFSIZE, OCI_ONE_PIECE, (void *)0,
(sb4 (*)()) 0, (ub2) csid, (ub1) SQLCS_IMPLICIT);
The amtp parameter is the data length in number of Unicode code units. The offset
parameter indicates the offset of data from the beginning of the data column. The
csid parameter must be set for UTF-16 data.
To read UTF-16 data from CLOB columns, call OCILobRead() as follows:
...
ub2 csid = OCI_UTF16ID;
err = OCILobRead(ctx->svchp, ctx->errhp, lobp, &amtp, offset, (void *) buf,
(ub4)BUFSIZE , (void *) 0, (sb4 (*)()) 0, (ub2)csid,
(ub1) SQLCS_IMPLICIT);
The data length is always represented in the number of Unicode code units. Note one
Unicode supplementary character is counted as two code units, because the encoding
is UTF-16. After binding or defining a LOB column, you can measure the data length
stored in the LOB column using OCILobGetLength(). The returning value is the data
length in the number of code units if you bind or define as UTF-16.
err = OCILobGetLength(ctx->svchp, ctx->errhp, lobp, &lenp);
If you are using an NCLOB, then you must set OCI_ATTR_CHARSET_FORM to SQLCS_
NCHAR.
Pro*C/C++ Programming with Unicode
Pro*C/C++ provides the following ways to insert or retrieve Unicode data into or
from the database:
■Using the VARCHAR Pro*C/C++ datatype or the native C/C++ text datatype, a
program can access Unicode data stored in SQL CHAR datatypes of a UTF8 or
AL32UTF8 database. Alternatively, a program could use the C/C++ native text
type.
■Using the UVARCHAR Pro*C/C++ datatype or the native C/C++ utext datatype, a
program can access Unicode data stored in NCHAR datatypes of a database.
■Using the NVARCHAR Pro*C/C++ datatype, a program can access Unicode data
stored in NCHAR datatypes. The difference between UVARCHAR and NVARCHAR in a
Pro*C/C++ program is that the data for the UVARCHAR datatype is stored in a
utext buffer while the data for the NVARCHAR datatype is stored in a text
datatype.
Pro*C/C++ does not use the Unicode OCI API for SQL text. As a result, embedded
SQL text must be encoded in the character set specified in the NLS_LANG environment
variable.
This section contains the following topics:
■Pro*C/C++ Data Conversion in Unicode
Pro*C/C++ Programming with Unicode
7-18 Oracle Database Globalization Support Guide
■Using the VARCHAR Datatype in Pro*C/C++
■Using the NVARCHAR Datatype in Pro*C/C++
■Using the UVARCHAR Datatype in Pro*C/C++
Pro*C/C++ Data Conversion in Unicode
Data conversion occurs in the OCI layer, but it is the Pro*C/C++ preprocessor that
instructs OCI which conversion path should be taken based on the datatypes used in a
Pro*C/C++ program. Table 7–4 illustrates the conversion paths:
Using the VARCHAR Datatype in Pro*C/C++
The Pro*C/C++ VARCHAR datatype is preprocessed to a struct with a length field
and text buffer field. The following example uses the C/C++ text native datatype
and the VARCHAR Pro*C/C++ datatypes to bind and define table columns.
#include <sqlca.h>
main()
{
...
/* Change to STRING datatype: */
EXEC ORACLE OPTION (CHAR_MAP=STRING) ;
text ename[20] ; /* unsigned short type */
varchar address[50] ; /* Pro*C/C++ varchar type */
EXEC SQL SELECT ename, address INTO :ename, :address FROM emp;
/* ename is NULL-terminated */
printf(L"ENAME = %s, ADDRESS = %.*s\n", ename, address.len, address.arr);
...
}
When you use the VARCHAR datatype or native text datatype in a Pro*C/C++
program, the preprocessor assumes that the program intends to access columns of SQL
CHAR datatypes instead of SQL NCHAR datatypes in the database. The preprocessor
Table 7–4 Pro*C/C++ Bind and Define Data Conversion
Pro*C/C++ Datatype SQL Datatype Conversion Path
VARCHAR or text CHAR NLS_LANG character set to and from the database character
set happens in OCI
VARCHAR or text NCHAR NLS_LANG character set to and from database character set
happens in OCI
Database character set to and from national character set
happens in database server
NVARCHAR NCHAR NLS_LANG character set to and from national character set
happens in OCI
NVARCHAR CHAR NLS_LANG character set to and from national character set
happens in OCI
National character set to and from database character set in
database server
UVARCHAR or utext NCHAR UTF-16 to and from the national character set happens in
OCI
UVARCHAR or utext CHAR UTF-16 to and from national character set happens in OCI
National character set to database character set happens in
database server
Pro*C/C++ Programming with Unicode
Programming with Unicode 7-19
generates C/C++ code to reflect this fact by doing a bind or define using the SQLCS_
IMPLICIT value for the OCI_ATTR_CHARSET_FORM attribute. As a result, if a bind or
define variable is bound to a column of SQL NCHAR datatypes in the database, then
implicit conversion occurs in the database server to convert the data from the database
character set to the national database character set and vice versa. During the
conversion, data loss occurs when the database character set is a smaller set than the
national character set.
Using the NVARCHAR Datatype in Pro*C/C++
The Pro*C/C++ NVARCHAR datatype is similar to the Pro*C/C++ VARCHAR datatype.
It should be used to access SQL NCHAR datatypes in the database. It tells Pro*C/C++
preprocessor to bind or define a text buffer to the column of SQL NCHAR datatypes.
The preprocessor specifies the SQLCS_NCHAR value for the OCI_ATTR_CHARSET_
FORM attribute of the bind or define variable. As a result, no implicit conversion occurs
in the database.
If the NVARCHAR buffer is bound against columns of SQL CHAR datatypes, then the
data in the NVARCHAR buffer (encoded in the NLS_LANG character set) is converted to
or from the national character set in OCI, and the data is then converted to the
database character set in the database server. Data can be lost when the NLS_LANG
character set is a larger set than the database character set.
Using the UVARCHAR Datatype in Pro*C/C++
The UVARCHAR datatype is preprocessed to a struct with a length field and utext
buffer field. The following example code contains two host variables, ename and
address. The ename host variable is declared as a utext buffer containing 20
Unicode characters. The address host variable is declared as a uvarchar buffer
containing 50 Unicode characters. The len and arr fields are accessible as fields of a
struct.
#include <sqlca.h>
#include <sqlucs2.h>
main()
{
...
/* Change to STRING datatype: */
EXEC ORACLE OPTION (CHAR_MAP=STRING) ;
utext ename[20] ; /* unsigned short type */
uvarchar address[50] ; /* Pro*C/C++ uvarchar type */
EXEC SQL SELECT ename, address INTO :ename, :address FROM emp;
/* ename is NULL-terminated */
wprintf(L"ENAME = %s, ADDRESS = %.*s\n", ename, address.len,
address.arr);
...
}
When you use the UVARCHAR datatype or native utext datatype in Pro*C/C++
programs, the preprocessor assumes that the program intends to access SQL NCHAR
datatypes. The preprocessor generates C/C++ code by binding or defining using the
SQLCS_NCHAR value for OCI_ATTR_CHARSET_FORM attribute. As a result, if a bind or
define variable is bound to a column of a SQL NCHAR datatype, then an implicit
conversion of the data from the national character set occurs in the database server.
However, there is no data lost in this scenario because the national character set is
always a larger set than the database character set.
JDBC Programming with Unicode
7-20 Oracle Database Globalization Support Guide
JDBC Programming with Unicode
Oracle provides the following JDBC drivers for Java programs to access character data
in an Oracle database:
■The JDBC OCI driver
■The JDBC thin driver
■The JDBC server-side internal driver
■The JDBC server-side thin driver
Java programs can insert or retrieve character data to and from columns of SQL CHAR
and NCHAR datatypes. Specifically, JDBC enables Java programs to bind or define Java
strings to SQL CHAR and NCHAR datatypes. Because Java's string datatype is UTF-16
encoded, data retrieved from or inserted into the database must be converted from
UTF-16 to the database character set or the national character set and vice versa. JDBC
also enables you to specify the PL/SQL and SQL statements in Java strings so that any
non-ASCII schema object names and string literals can be used.
At database connection time, JDBC sets the server NLS_LANGUAGE and NLS_
TERRITORY parameters to correspond to the locale of the Java VM that runs the JDBC
driver. This operation ensures that the server and the Java client communicate in the
same language. As a result, Oracle error messages returned from the server are in the
same language as the client locale.
This section contains the following topics:
■Binding and Defining Java Strings to SQL CHAR Datatypes
■Binding and Defining Java Strings to SQL NCHAR Datatypes
■Using the SQL NCHAR Datatypes Without Changing the Code
■Using SQL NCHAR String Literals in JDBC
■Data Conversion in JDBC
■Using oracle.sql.CHAR in Oracle Object Types
■Restrictions on Accessing SQL CHAR Data with JDBC
Binding and Defining Java Strings to SQL CHAR Datatypes
Oracle JDBC drivers allow you to access SQL CHAR datatypes in the database using
Java string bind or define variables. The following code illustrates how to bind a Java
string to a CHAR column.
int employee_id = 12345;
String last_name = "Joe";
PreparedStatement pstmt = conn.prepareStatement("INSERT INTO" +
"employees (last_name, employee_id) VALUES (?, ?)");
pstmt.setString(1, last_name);
pstmt.setInt(2, employee_id);
pstmt.execute(); /* execute to insert into first row */
employee_id += 1; /* next employee number */
last_name = "\uFF2A\uFF4F\uFF45"; /* Unicode characters in name */
pstmt.setString(1, last_name);
pstmt.setInt(2, employee_id);
pstmt.execute(); /* execute to insert into second row */
You can define the target SQL columns by specifying their datatypes and lengths.
When you define a SQL CHAR column with the datatype and the length, JDBC uses
JDBC Programming with Unicode
Programming with Unicode 7-21
this information to optimize the performance of fetching SQL CHAR data from the
column. The following is an example of defining a SQL CHAR column.
OraclePreparedStatement pstmt = (OraclePreparedStatement)
conn.prepareStatement("SELECT ename, empno from emp");
pstmt.defineColumnType(1,Types.VARCHAR, 3);
pstmt.defineColumnType(2,Types.INTEGER);
ResultSet rest = pstmt.executeQuery();
String name = rset.getString(1);
int id = reset.getInt(2);
You need to cast PreparedStatement to OraclePreparedStatement to call
defineColumnType(). The second parameter of defineColumnType() is the
datatype of the target SQL column. The third parameter is the length in number of
characters.
Binding and Defining Java Strings to SQL NCHAR Datatypes
For binding or defining Java string variables to SQL NCHAR datatypes, Oracle provides
an extended PreparedStatement which has the setFormOfUse() method through
which you can explicitly specify the target column of a bind variable to be a SQL
NCHAR datatype. The following code illustrates how to bind a Java string to an NCHAR
column.
int employee_id = 12345;
String last_name = "Joe"
oracle.jdbc.OraclePreparedStatement pstmt =
(oracle.jdbc.OraclePreparedStatement)
conn.prepareStatement("INSERT INTO employees (last_name, employee_id)
VALUES (?, ?)");
pstmt.setFormOfUse(1, oracle.jdbc.OraclePreparedStatement.FORM_NCHAR);
pstmt.setString(1, last_name);
pstmt.setInt(2, employee_id);
pstmt.execute(); /* execute to insert into first row */
employee_id += 1; /* next employee number */
last_name = "\uFF2A\uFF4F\uFF45"; /* Unicode characters in name */
pstmt.setString(1, last_name);
pstmt.setInt(2, employee_id);
pstmt.execute(); /* execute to insert into second row */
You can define the target SQL NCHAR columns by specifying their datatypes, forms of
use, and lengths. JDBC uses this information to optimize the performance of fetching
SQL NCHAR data from these columns. The following is an example of defining a SQL
NCHAR column.
OraclePreparedStatement pstmt = (OraclePreparedStatement)
conn.prepareStatement("SELECT ename, empno from emp");
pstmt.defineColumnType(1,Types.VARCHAR, 3,
OraclePreparedStatement.FORM_NCHAR);
pstmt.defineColumnType(2,Types.INTEGER);
ResultSet rest = pstmt.executeQuery();
String name = rset.getString(1);
int id = reset.getInt(2);
To define a SQL NCHAR column, you need to specify the datatype that is equivalent to
a SQL CHAR column in the first argument, the length in number of characters in the
second argument, and the form of use in the fourth argument of
defineColumnType().
JDBC Programming with Unicode
7-22 Oracle Database Globalization Support Guide
You can bind or define a Java string against an NCHAR column without explicitly
specifying the form of use argument. This implies the following:
■If you do not specify the argument in the setString() method, then JDBC
assumes that the bind or define variable is for the SQL CHAR column. As a result, it
tries to convert them to the database character set. When the data gets to the
database, the database implicitly converts the data in the database character set to
the national character set. During this conversion, data can be lost when the
database character set is a subset of the national character set. Because the national
character set is either UTF8 or AL16UTF16, data loss would happen if the database
character set is not UTF8 or AL32UTF8.
■Because implicit conversion from SQL CHAR to SQL NCHAR datatypes happens in
the database, database performance is degraded.
In addition, if you bind or define a Java string for a column of SQL CHAR datatypes but
specify the form of use argument, then performance of the database is degraded.
However, data should not be lost because the national character set is always a larger
set than the database character set.
Using the SQL NCHAR Datatypes Without Changing the Code
A Java system property has been introduced in the Oracle JDBC drivers for customers
to tell whether the form of use argument should be specified by default in a Java
application. This property has the following purposes:
■Existing applications accessing the SQL CHAR datatypes can be migrated to
support the SQL NCHAR datatypes for worldwide deployment without changing a
line of code.
■Applications do not need to call the setFormOfUse() method when binding and
defining a SQL NCHAR column. The application code can be made neutral and
independent of the datatypes being used in the backend database. With this
property set, applications can be easily switched from using SQL CHAR or SQL
NCHAR.
The Java system property is specified in the command line that invokes the Java
application. The syntax of specifying this flag is as follows:
java -Doracle.jdbc.defaultNChar=true <application class>
With this property specified, the Oracle JDBC drivers assume the presence of the form
of use argument for all bind and define operations in the application.
If you have a database schema that consists of both the SQL CHAR and SQL NCHAR
columns, then using this flag may have some performance impact when accessing the
SQL CHAR columns because of implicit conversion done in the database server.
Using SQL NCHAR String Literals in JDBC
When using NCHAR string literals in JDBC, there is a potential for data loss because
characters are converted to the database character set before processing. See NCHAR
String Literal Replacement on page 7-9 for more details.
The desired behavior for preserving the NCHAR string literals can be achieved by
enabling the property set oracle.jdbc.convertNcharLiterals. If the value is
true, then this option is enabled; otherwise, it is disabled. The default setting is false. It
See Also: "Data Conversion in JDBC" on page 7-23 for more
information about the performance impact of implicit conversion
JDBC Programming with Unicode
Programming with Unicode 7-23
can be enabled in two ways: a) as a Java system property or b) as a connection
property. Once enabled, conversion is performed on all SQL in the VM (system
property) or in the connection (connection property). For example, the property can be
set as a Java system property as follows:
java -Doracle.jdbc.convertNcharLiterals="true" ...
Alternatively, you can set this as a connection property as follows:
Properties props = new Properties();
...
props.setProperty("oracle.jdbc.convertNcharLiterals", "true");
Connection conn = DriverManager.getConnection(url, props);
If you set this as a connection property, it overrides a system property setting.
Data Conversion in JDBC
Because Java strings are always encoded in UTF-16, JDBC drivers transparently
convert data from the database character set to UTF-16 or the national character set.
The conversion paths taken are different for the JDBC drivers:
■Data Conversion for the OCI Driver
■Data Conversion for Thin Drivers
■Data Conversion for the Server-Side Internal Driver
Data Conversion for the OCI Driver
For the OCI driver, the SQL statements are always converted to the database character
set by the driver before it is sent to the database for processing. When the database
character set is neither US7ASCII nor WE8ISO8859P1, the driver converts the SQL
statements to UTF-8 first in Java and then to the database character set in C.
Otherwise, it converts the SQL statements directly to the database character set. For
Java string bind or define variables, Table 7–5 summarizes the conversion paths taken
for different scenarios.
Data Conversion for Thin Drivers
SQL statements are always converted to either the database character set or to UTF-8
by the driver before they are sent to the database for processing. When the database
character set is either US7ASCII or WE8ISO8859P1, the driver converts the SQL
statement to the database character set. Otherwise, the driver converts the SQL
statement to UTF-8 and notifies the database that a SQL statement requires further
Table 7–5 OCI Driver Conversion Path
Form of Use SQL Datatype Conversion Path
Const.CHAR
(Default)
CHAR Java string to and from database character set happens in the JDBC driver.
Const.CHAR
(Default)
NCHAR Java string to and from database character set happens in the JDBC driver.
Data in the database character set to and from national character set
happens in the database server.
Const.NCHAR NCHAR Java string to and from national character set happens in the JDBC driver.
Const.NCHAR CHAR Java string to and from national character set happens in the JDBC driver.
Data in national character set to and from database character set happens
in the database server.
JDBC Programming with Unicode
7-24 Oracle Database Globalization Support Guide
conversion before being processed. The database, in turn, converts the SQL statements
from UTF-8 to the database character set. The database, in turn, converts the SQL
statement to the database character set. For Java string bind and define variables, the
conversion paths shown in Table 7–6 are taken for the thin driver.
Data Conversion for the Server-Side Internal Driver
All data conversion occurs in the database server because the server-side internal
driver works inside the database.
Using oracle.sql.CHAR in Oracle Object Types
JDBC drivers support Oracle object types. Oracle objects are always sent from database
to client as an object represented in the database character set or national character set.
That means the data conversion path in "Data Conversion in JDBC" on page 7-23 does
not apply to Oracle object access. Instead, the oracle.sql.CHAR class is used for
passing SQL CHAR and SQL NCHAR data of an object type from the database to the
client.
This section includes the following topics:
■oracle.sql.CHAR
■Accessing SQL CHAR and NCHAR Attributes with oracle.sql.CHAR
oracle.sql.CHAR
The oracle.sql.CHAR class has a special functionality for conversion of character
data. The Oracle character set is a key attribute of the oracle.sql.CHAR class. The
Oracle character set is always passed in when an oracle.sql.CHAR object is
Table 7–6 Thin Driver Conversion Path
Form of Use SQL Datatype
Database
Character Set Conversion Path
Const.CHAR
(Default)
CHAR US7ASCII or
WE8ISO8859P1 Java string to and from the database character set
happens in the thin driver.
Const.CHAR
(Default)
NCHAR US7ASCII or
WE8ISO8859P1 Java string to and from the database character set
happens in the thin driver.
Data in the database character set to and from the
national character set happens in the database server.
Const.CHAR
(Default)
CHAR non-ASCII and
non-WE8ISO8859P1 Java string to and from UTF-8 happens in the thin
driver.
Data in UTF-8 to and from the database character set
happens in the database server.
Const.CHAR
(Default)
NCHAR non-ASCII and
non-WE8ISO8859P1 Java string to and from UTF-8 happens in the thin
driver.
Data in UTF-8 to and from national character set
happens in the database server.
Const.NCHAR CHAR Java string to and from the national character set
happens in the thin driver.
Data in the national character set to and from the
database character set happens in the database server.
Const.NCHAR NCHAR Java string to and from the national character set
happens in the thin driver.
JDBC Programming with Unicode
Programming with Unicode 7-25
constructed. Without a known character set, the bytes of data in the
oracle.sql.CHAR object are meaningless.
The oracle.sql.CHAR class provides the following methods for converting
character data to strings:
■getString()
Converts the sequence of characters represented by the oracle.sql.CHAR object
to a string, returning a Java string object. If the character set is not recognized, then
getString() returns a SQLException.
■toString()
Identical to getString(), except that if the character set is not recognized, then
toString() returns a hexadecimal representation of the oracle.sql.CHAR
data and does not returns a SQLException.
■getStringWithReplacement()
Identical to getString(), except that a default replacement character replaces
characters that have no Unicode representation in the character set of this
oracle.sql.CHAR object. This default character varies among character sets, but
it is often a question mark.
You may want to construct an oracle.sql.CHAR object yourself (to pass into a
prepared statement, for example). When you construct an oracle.sql.CHAR object,
you must provide character set information to the oracle.sql.CHAR object by using
an instance of the oracle.sql.CharacterSet class. Each instance of the
oracle.sql.CharacterSet class represents one of the character sets that Oracle
supports.
Complete the following tasks to construct an oracle.sql.CHAR object:
1. Create a CharacterSet instance by calling the static CharacterSet.make()
method. This method creates the character set class. It requires as input a valid
Oracle character set (OracleId). For example:
int OracleId = CharacterSet.JA16SJIS_CHARSET; // this is character set 832
...
CharacterSet mycharset = CharacterSet.make(OracleId);
Each character set that Oracle supports has a unique predefined OracleId. The
OracleId can always be referenced as a character set specified as Oracle_
character_set_name_CHARSET where Oracle_character_set_name is the
Oracle character set.
2. Construct an oracle.sql.CHAR object. Pass to the constructor a string (or the
bytes that represent the string) and the CharacterSet object that indicates how
to interpret the bytes based on the character set. For example:
String mystring = "teststring";
...
oracle.sql.CHAR mychar = new oracle.sql.CHAR(teststring, mycharset);
The oracle.sql.CHAR class has multiple constructors: they can take a string, a
byte array, or an object as input along with the CharacterSet object. In the case
of a string, the string is converted to the character set indicated by the
CharacterSet object before being placed into the oracle.sql.CHAR object.
The server (database) and the client (or application running on the client) can use
different character sets. When you use the methods of this class to transfer data
JDBC Programming with Unicode
7-26 Oracle Database Globalization Support Guide
between the server and the client, the JDBC drivers must convert the data between the
server character set and the client character set.
Accessing SQL CHAR and NCHAR Attributes with oracle.sql.CHAR
The following is an example of an object type created using SQL:
CREATE TYPE person_type AS OBJECT (
name VARCHAR2(30), address NVARCHAR2(256), age NUMBER);
CREATE TABLE employees (id NUMBER, person PERSON_TYPE);
The Java class corresponding to this object type can be constructed as follows:
public class person implement SqlData
{
oracle.sql.CHAR name;
oracle.sql.CHAR address;
oracle.sql.NUMBER age;
// SqlData interfaces
getSqlType() {...}
writeSql(SqlOutput stream) {...}
readSql(SqlInput stream, String sqltype) {...}
}
The oracle.sql.CHAR class is used here to map to the NAME attributes of the Oracle
object type, which is of VARCHAR2 datatype. JDBC populates this class with the byte
representation of the VARCHAR2 data in the database and the CharacterSet object
corresponding to the database character set. The following code retrieves a person
object from the employees table:
TypeMap map = ((OracleConnection)conn).getTypeMap();
map.put("PERSON_TYPE", Class.forName("person"));
conn.setTypeMap(map);
. . .
. . .
ResultSet rs = stmt.executeQuery(
"SELECT PERSON FROM EMPLOYEES");
rs.next();
person p = (person) rs.getObject(1);
oracle.sql.CHAR sql_name = p.name;
oracle.sql.CHAR sql_address=p.address;
String java_name = sql_name.getString();
String java_address = sql_address.getString();
The getString() method of the oracle.sql.CHAR class converts the byte array
from the database character set or national character set to UTF-16 by calling Oracle's
Java data conversion classes and returning a Java string. For the rs.getObject(1)
call to work, the SqlData interface has to be implemented in the class person, and
the Typemap map has to be set up to indicate the mapping of the object type PERSON_
TYPE to the Java class.
Restrictions on Accessing SQL CHAR Data with JDBC
This section contains the following topic:
■Character Integrity Issues in a Multibyte Database Environment
Character Integrity Issues in a Multibyte Database Environment
Oracle JDBC drivers perform character set conversions as appropriate when character
data is inserted into or retrieved from the database. The drivers convert Unicode
ODBC and OLE DB Programming with Unicode
Programming with Unicode 7-27
characters used by Java clients to Oracle database character set characters, and vice
versa. Character data that makes a round trip from the Java Unicode character set to
the database character set and back to Java can suffer some loss of information. This
happens when multiple Unicode characters are mapped to a single character in the
database character set. An example is the Unicode full-width tilde character (0xFF5E)
and its mapping to Oracle's JA16SJIS character set. The round-trip conversion for this
Unicode character results in the Unicode character 0x301C, which is a wave dash (a
character commonly used in Japan to indicate range), not a tilde.
Figure 7–2 shows the round-trip conversion of the tilde character.
Figure 7–2 Character Integrity
This issue is not a bug in Oracle's JDBC. It is an unfortunate side effect of the
ambiguity in character mapping specifications on different operating systems.
Fortunately, this problem affects only a small number of characters in a small number
of Oracle character sets such as JA16SJIS, JA16EUC, ZHT16BIG5, and KO16KS5601.
The workaround is to avoid making a full round-trip with these characters.
ODBC and OLE DB Programming with Unicode
You should use the Oracle ODBC driver or Oracle Provider for OLE DB to access the
Oracle server when using a Windows platform. This section describes how these
drivers support Unicode. It includes the following topics:
■Unicode-Enabled Drivers in ODBC and OLE DB
■OCI Dependency in Unicode
■ODBC and OLE DB Code Conversion in Unicode
■ODBC Unicode Datatypes
■OLE DB Unicode Datatypes
■ADO Access
Unicode-Enabled Drivers in ODBC and OLE DB
Oracle's ODBC driver and Oracle Provider for OLE DB can handle Unicode data
properly without data loss. For example, you can run a Unicode ODBC application
containing Japanese data on English Windows if you install Japanese fonts and an
input method editor for entering Japanese characters.
Oracle database
Character Set
(JA16SJIS) Java UnicodeJava Unicode
0x8160
0xFF5E
0x301C
0x301C
0xFF5E
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
ODBC and OLE DB Programming with Unicode
7-28 Oracle Database Globalization Support Guide
Oracle provides ODBC and OLE DB products for Windows platforms only. For Unix
platforms, contact your vendor.
OCI Dependency in Unicode
OCI Unicode binding and defining features are used by the ODBC and OLE DB
drivers to handle Unicode data. OCI Unicode data binding and defining features are
independent from NLS_LANG. This means Unicode data is handled properly,
irrespective of the NLS_LANG setting on the platform.
ODBC and OLE DB Code Conversion in Unicode
In general, no redundant data conversion occurs unless you specify a different client
datatype from that of the server. If you bind Unicode buffer SQL_C_WCHAR with a
Unicode data column like NCHAR, for example, then ODBC and OLE DB drivers
bypass it between the application and OCI layer.
If you do not specify datatypes before fetching, but call SQLGetData with the client
datatypes instead, then the conversions in Table 7–7 occur.
You must specify the datatype for inserting and updating operations.
The datatype of the ODBC client buffer is given when you call SQLGetData but not
immediately. Hence, SQLFetch does not have the information.
Because the ODBC driver guarantees data integrity, if you perform implicit bindings,
then redundant conversion may result in performance degradation. Your choice is the
trade-off between performance with explicit binding or usability with implicit binding.
See Also: "OCI Programming with Unicode" on page 7-10
Table 7–7 ODBC Implicit Binding Code Conversions
Datatypes of ODBC
Client Buffer
Datatypes of the
Target Column in
the Database Fetch Conversions Comments
SQL_C_WCHAR CHAR,
VARCHAR2,
CLOB
If the database character set is a subset
of the NLS_LANG character set, then the
conversions occur in the following
order:
■Database character set
■NLS_LANG
■UTF-16 in OCI
■UTF-16 in ODBC
No unexpected data loss
May degrade performance
if database character set is
a subset of the NLS_LANG
character set
SQL_C_CHAR CHAR,
VARCHAR2,
CLOB
If database character set is a subset of
NLS_LANG character set:
Database character set to NLS_LANG in
OCI
If database character set is NOT a subset
of NLS_LANG character set:
Database character set, UTF-16, to NLS_
LANG character set in OCI and ODBC
No unexpected data loss
May degrade performance
if database character set is
not a subset of NLS_LANG
character set
ODBC and OLE DB Programming with Unicode
Programming with Unicode 7-29
OLE DB Code Conversions
Unlike ODBC, OLE DB only enables you to perform implicit bindings for inserting,
updating, and fetching data. The conversion algorithm for determining the
intermediate character set is the same as the implicit binding cases of ODBC.
ODBC Unicode Datatypes
In ODBC Unicode applications, use SQLWCHAR to store Unicode data. All standard
Windows Unicode functions can be used for SQLWCHAR data manipulations. For
example, wcslen counts the number of characters of SQLWCHAR data:
SQLWCHAR sqlStmt[] = L"select ename from emp";
len = wcslen(sqlStmt);
Microsoft's ODBC 3.5 specification defines three Unicode datatype identifiers for the
SQL_C_WCHAR, SQL_C_WVARCHAR, and SQL_WLONGVARCHAR clients; and three
Unicode datatype identifiers for servers SQL_WCHAR, SQL_WVARCHAR, and SQL_
WLONGVARCHAR.
For binding operations, specify datatypes for both client and server using
SQLBindParameter. The following is an example of Unicode binding, where the
client buffer Name indicates that Unicode data (SQL_C_WCHAR) is bound to the first
bind variable associated with the Unicode column (SQL_WCHAR):
SQLBindParameter(StatementHandle, 1, SQL_PARAM_INPUT, SQL_C_WCHAR,
SQL_WCHAR, NameLen, 0, (SQLPOINTER)Name, 0, &Name);
Table 7–8 OLE DB Implicit Bindings
Datatypes of OLE_
DB Client Buffer
Datatypes of the
Target Column in the
Database
In-Binding and Out-Binding
Conversions Comments
DBTYPE_WCHAR CHAR,
VARCHAR2,
CLOB
If database character set is a
subset of the NLS_LANG character
set:
Database character set to and from
NLS_LANG character set in OCI.
NLS_LANG character set to UTF-16
in OLE DB
If database character set is NOT a
subset of NLS_LANG character set:
Database character set to and from
UTF-16 in OCI
No unexpected data loss
May degrade performance if
database character set is a
subset of NLS_LANG character
set
DBTYPE_CHAR CHAR,
VARCHAR2,
CLOB
If database character set is a
subset of the NLS_LANG character
set:
Database character set to and from
NLS_LANG in OCI
If database character set is not a
subset of NLS_LANG character set:
Database character set to and from
UTF-16 in OCI. UTF-16 to NLS_
LANG character set in OLE DB
No unexpected data loss
May degrade performance if
database character set is not a
subset of NLS_LANG character
set
ODBC and OLE DB Programming with Unicode
7-30 Oracle Database Globalization Support Guide
Table 7–9 represents the datatype mappings of the ODBC Unicode datatypes for the
server against SQL NCHAR datatypes.
According to ODBC specifications, SQL_WCHAR, SQL_WVARCHAR, and SQL_
WLONGVARCHAR are treated as Unicode data, and are therefore measured in the
number of characters instead of the number of bytes.
OLE DB Unicode Datatypes
OLE DB offers the wchar_t, BSTR, and OLESTR datatypes for a Unicode C client. In
practice, wchar_t is the most common datatype and the others are for specific
purposes. The following example assigns a static SQL statement:
wchar_t *sqlStmt = OLESTR("SELECT ename FROM emp");
The OLESTR macro works exactly like an "L" modifier to indicate the Unicode string. If
you need to allocate Unicode data buffer dynamically using OLESTR, then use the
IMalloc allocator (for example, CoTaskMemAlloc). However, using OLESTR is not
the normal method for variable length data; use wchar_t* instead for generic string
types. BSTR is similar. It is a string with a length prefix in the memory location
preceding the string. Some functions and methods can accept only BSTR Unicode
datatypes. Therefore, BSTR Unicode string must be manipulated with special
functions like SysAllocString for allocation and SysFreeString for freeing
memory.
Unlike ODBC, OLE DB does not allow you to specify the server datatype explicitly.
When you set the client datatype, the OLE DB driver automatically performs data
conversion if necessary.
Table 7–10 illustrates OLE DB datatype mapping.
If DBTYPE_BSTR is specified, then it is assumed to be DBTYPE_WCHAR because both
are Unicode strings.
ADO Access
ADO is a high-level API to access database with the OLE DB and ODBC drivers. Most
database application developers use the ADO interface on Windows because it is
easily accessible from Visual Basic, the primary scripting language for Active Server
Pages (ASP) for the Internet Information Server (IIS). To OLE DB and ODBC drivers,
ADO is simply an OLE DB consumer or ODBC application. ADO assumes that OLE
DB and ODBC drivers are Unicode-aware components; hence, it always attempts to
manipulate Unicode data.
Table 7–9 Server ODBC Unicode Datatype Mapping
ODBC Datatype Oracle Datatype
SQL_WCHAR NCHAR
SQL_WVARCHAR NVARCHAR2
SQL_WLONGVARCHAR NCLOB
Table 7–10 OLE DB Datatype Mapping
OLE DB Datatype Oracle Datatype
DBTYPE_WCHAR NCHAR or NVARCHAR2
XML Programming with Unicode
Programming with Unicode 7-31
XML Programming with Unicode
XML support of Unicode is essential for software development for global markets so
that text information can be exchanged in any language. Unicode uniformly supports
almost every character and language, which makes it much easier to support multiple
languages within XML. To enable Unicode for XML within an Oracle database, the
character set of the database must be UTF-8. By enabling Unicode text handling in
your application, you acquire a basis for supporting any language. Every XML
document is Unicode text and potentially multilingual, unless it is guaranteed that
only a known subset of Unicode characters will appear on your documents. Thus
Oracle recommends that you enable Unicode for XML. Unicode support comes with
Java and many other modern programming environments.
This section includes the following topics:
■Writing an XML File in Unicode with Java
■Reading an XML File in Unicode with Java
■Parsing an XML Stream in Unicode with Java
Writing an XML File in Unicode with Java
A common mistake in reading and writing XML files is using the Reader and Writer
classes for character input and output. Using Reader and Writer for XML files
should be avoided because it requires character set conversion based on the default
character encoding of the runtime environment.
For example, using FileWriter class is not safe because it converts the document to
the default character encoding. The output file can suffer from a parsing error or data
loss if the document contains characters that are not available in the default character
encoding.
UTF-8 is popular for XML documents, but UTF-8 is not usually the default file
encoding for Java. Thus using a Java class that assumes the default file encoding can
cause problems.
The following example shows how to avoid these problems:
import java.io.*;
import oracle.xml.parser.v2.*;
public class I18nSafeXMLFileWritingSample
{
public static void main(String[] args) throws Exception
{
// create a test document
XMLDocument doc = new XMLDocument();
doc.setVersion( "1.0" );
doc.appendChild(doc.createComment( "This is a test empty document." ));
doc.appendChild(doc.createElement( "root" ));
// create a file
File file = new File( "myfile.xml" );
// create a binary output stream to write to the file just created
FileOutputStream fos = new FileOutputStream( file );
// create a Writer that converts Java character stream to UTF-8 stream
OutputStreamWriter osw = new OutputStreamWriter( fos, "UTF8" );
XML Programming with Unicode
7-32 Oracle Database Globalization Support Guide
// buffering for efficiency
Writer w = new BufferedWriter( osw );
// create a PrintWriter to adapt to the printing method
PrintWriter out = new PrintWriter( w );
// print the document to the file through the connected objects
doc.print( out );
}
}
Reading an XML File in Unicode with Java
Do not read XML files as text input. When reading an XML document stored in a file
system, use the parser to automatically detect the character encoding of the document.
Avoid using a Reader class or specifying a character encoding on the input stream.
Given a binary input stream with no external encoding information, the parser
automatically figures out the character encoding based on the byte order mark and
encoding declaration of the XML document. Any well-formed document in any
supported encoding can be successfully parsed using the following sample code:
import java.io.*;
import oracle.xml.parser.v2.*;
public class I18nSafeXMLFileReadingSample
{
public static void main(String[] args) throws Exception
{
// create an instance of the xml file
File file = new File( "myfile.xml" );
// create a binary input stream
FileInputStream fis = new FileInputStream( file );
// buffering for efficiency
BufferedInputStream in = new BufferedInputStream( fis );
// get an instance of the parser
DOMParser parser = new DOMParser();
// parse the xml file
parser.parse( in );
}
}
Parsing an XML Stream in Unicode with Java
When the source of an XML document is not a file system, the encoding information is
usually available before reading the document. For example, if the input document is
provided in the form of a Java character stream or Reader, its encoding is evident and
no detection should take place. The parser can begin parsing a Reader in Unicode
without regard to the character encoding.
The following is an example of parsing a document with external encoding
information:
import java.io.*;
import java.net.*;
import org.xml.sax.*;
import oracle.xml.parser.v2.*;
XML Programming with Unicode
Programming with Unicode 7-33
public class I18nSafeXMLStreamReadingSample
{
public static void main(String[] args) throws Exception
{
// create an instance of the xml file
URL url = new URL( "http://myhost/mydocument.xml" );
// create a connection to the xml document
URLConnection conn = url.openConnection();
// get an input stream
InputStream is = conn.getInputStream();
// buffering for efficiency
BufferedInputStream bis = new BufferedInputStream( is );
/* figure out the character encoding here */
/* a typical source of encoding information is the content-type header */
/* we assume it is found to be utf-8 in this example */
String charset = "utf-8";
// create an InputSource for UTF-8 stream
InputSource in = new InputSource( bis );
in.setEncoding( charset );
// get an instance of the parser
DOMParser parser = new DOMParser();
// parse the xml stream
parser.parse( in );
}
}
XML Programming with Unicode
7-34 Oracle Database Globalization Support Guide
Oracle Globalization Development Kit 8-1
8
Oracle Globalization Development Kit
This chapter includes the following sections:
■Overview of the Oracle Globalization Development Kit
■Designing a Global Internet Application
■Developing a Global Internet Application
■Getting Started with the Globalization Development Kit
■GDK Quick Start
■GDK Application Framework for J2EE
■GDK Java API
■The GDK Application Configuration File
■GDK for Java Supplied Packages and Classes
■GDK for PL/SQL Supplied Packages
■GDK Error Messages
Overview of the Oracle Globalization Development Kit
Designing and developing a globalized application can be a daunting task even for the
most experienced developers. This is usually caused by lack of knowledge and the
complexity of globalization concepts and APIs. Application developers who write
applications using Oracle Database need to understand the Globalization Support
architecture of the database, including the properties of the different character sets,
territories, languages and linguistic sort definitions. They also need to understand the
globalization functionality of their middle-tier programming environment, and find
out how it can interact and synchronize with the locale model of the database. Finally,
to develop a globalized Internet application, they need to design and write code that is
capable of simultaneously supporting multiple clients running on different operating
systems, with different character sets and locale requirements.
Oracle Globalization Development Kit (GDK) simplifies the development process and
reduces the cost of developing Internet applications that will be used to support a
global environment. The GDK includes comprehensive programming APIs for both
Java and PL/SQL, code samples, and documentation that address many of the design,
development, and deployment issues encountered while creating global applications.
The GDK mainly consists of two parts: GDK for Java and GDK for PL/SQL. GDK for
Java provides globalization support to Java applications. GDK for PL/SQL provides
globalization support to the PL/SQL programming environment. The features offered
in GDK for Java and GDK for PL/SQL are not identical.
Designing a Global Internet Application
8-2 Oracle Database Globalization Support Guide
Designing a Global Internet Application
There are two architectural models for deploying a global Web site or a global Internet
application, depending on your globalization and business requirements. Which
model to deploy affects how the Internet application is developed and how the
application server is configured in the middle-tier. The two models are:
■Multiple instances of monolingual Internet applications
Internet applications that support only one locale in a single binary are classified
as monolingual applications. A locale refers to a national language and the region
in which the language is spoken. For example, the primary language of the United
States and Great Britain is English. However, the two territories have different
currencies and different conventions for date formats. Therefore, the United States
and Great Britain are considered to be two different locales.
This level of globalization support is suitable for customers who want to support
one locale for each instance of the application. Users need to have different entry
points to access the applications for different locales. This model is manageable
only if the number of supported locales is small.
■Single instance of a multilingual application
Internet applications that support multiple locales simultaneously in a single
binary are classified as multilingual applications. This level of globalization
support is suitable for customers who want to support several locales in an
Internet application simultaneously. Users of different locale preferences use the
same entry point to access the application.
Developing an application using the monolingual model is very different from
developing an application using the multilingual model. The Globalization
Development Kit consists of libraries, which can assist in the development of
global applications using either architectural model.
The rest of this section includes the following topics:
■Deploying a Monolingual Internet Application
■Deploying a Multilingual Internet Application
Deploying a Monolingual Internet Application
Deploying a global Internet application with multiple instances of monolingual
Internet applications is shown in Figure 8–1.
Designing a Global Internet Application
Oracle Globalization Development Kit 8-3
Figure 8–1 Monolingual Internet Application Architecture
Each application server is configured for the locale that it serves. This deployment
model assumes that one instance of an Internet application runs in the same locale as
the application in the middle tier.
The Internet applications access a back-end database in the native encoding used for
the locale. The following are advantages of deploying monolingual Internet
applications:
■The support of the individual locales is separated into different servers so that
multiple locales can be supported independently in different locations and that the
workload can be distributed accordingly. For example, customers may want to
support Western European locales first and then support Asian locales such as
Japanese (Japan) later.
■The complexity required to support multiple locales simultaneously is avoided.
The amount of code to write is significantly less for a monolingual Internet
application than for a multilingual Internet application.
The following are disadvantages of deploying monolingual Internet applications:
■Extra effort is required to maintain and manage multiple servers for different
locales. Different configurations are required for different application servers.
■The minimum number of application servers required depends on the number of
locales the application supports, regardless of whether the site traffic will reach the
capacity provided by the application servers.
English
Locale
Japanese
Locale
Hebrew
Locale
Monolingual
Application:
Japanese Locale
Shift-JIS
ISO-8859-1
ISO-8859-8
JAI6SJIS
Monolingual
Application:
English Locale
Application Server
WE8MSWIN1252
Monolingual
Application:
Hebrew Locale
IW8MSWIN1255
HTTP
Oracle Net
Oracle
Unicode
Database
Browsers Customer
Database
Application Server
Instance 1
Application Server
Instance 2
Server A
Application Server
Instance 3
Server B
Designing a Global Internet Application
8-4 Oracle Database Globalization Support Guide
■Load balancing for application servers is limited to the group of application
servers for the same locale.
■More QA resources, both human and machine, are required for multiple
configurations of application servers. Internet applications running on different
locales must be certified on the corresponding application server configuration.
■It is not designed to support multilingual content. For example, a web page
containing Japanese and Arabic data cannot be easily supported in this model.
As more and more locales are supported, the disadvantages quickly outweigh the
advantages. With the limitation and the maintenance overhead of the monolingual
deployment model, this deployment architecture is suitable for applications that
support only one or two locales.
Deploying a Multilingual Internet Application
Multilingual Internet applications are deployed to the application servers with a single
application server configuration that works for all locales. Figure 8–2 shows the
architecture of a multilingual Internet application.
Figure 8–2 Multilingual Internet Application Architecture
To support multiple locales in a single application instance, the application may need
to do the following:
■Dynamically detect the locale of the users and adapt to the locale by constructing
HTML pages in the language and cultural conventions of the locale
English
Locale
Japanese
Locale
Hebrew
Locale
Thai
Locale
Multilingual
Application with
Dynamic Locale
Switching
Application Server
Instance
Shift-JIS
ISO-8859-1
UTF-8
UTF-8
Oracle
Unicode
Database
Unicode
HTTP
Oracle Net
Browsers Customer
Database
Server
Developing a Global Internet Application
Oracle Globalization Development Kit 8-5
■Process character data in Unicode so that data in any language can be supported.
Character data can be entered by users or retrieved from back-end databases.
■Dynamically determine the HTML page encoding (or character set) to be used for
HTML pages and convert content from Unicode to the page encoding and the
reverse.
The following are major advantages of deploying multilingual Internet application:
■Using a single application server configuration for all application servers
simplifies the deployment configuration and hence reduces the cost of
maintenance.
■Performance tuning and capacity planning do not depend on the number of
locales supported by the Web site.
■Introducing additional locales is relatively easy. No extra machines are necessary
for the new locales.
■Testing the application across different locales can be done in a single testing
environment.
■This model can support multilingual content within the same instance of the
application. For example, a web page containing Japanese, Chinese, English and
Arabic data can be easily supported in this model.
The disadvantage of deploying multilingual Internet applications is that it requires
extra coding during application development to handle dynamic locale detection and
Unicode, which is costly when only one or two languages need to be supported.
Deploying multilingual Internet applications is more appropriate than deploying
monolingual applications when Web sites support multiple locales.
Developing a Global Internet Application
Building an Internet application that supports different locales requires good
development practices.
For multilingual Internet applications, the application itself must be aware of the user's
locale and be able to present locale-appropriate content to the user. Clients must be
able to communicate with the application server regardless of the client's locale. The
application server then communicates with the database server, exchanging data while
maintaining the preferences of the different locales and character set settings. One of
the main considerations when developing a multilingual Internet application is to be
able to dynamically detect, cache, and provide the appropriate contents according to
the user's preferred locale.
For monolingual Internet applications, the locale of the user is always fixed and
usually follows the default locale of the runtime environment. Hence the locale
configuration is much simpler.
The following sections describe some of the most common issues that developers
encounter when building a global Internet application:
■Locale Determination
■Locale Awareness
■Localizing the Content
Developing a Global Internet Application
8-6 Oracle Database Globalization Support Guide
Locale Determination
To be locale-aware or locale-sensitive, Internet applications need to be able to
determine the preferred locale of the user.
Monolingual applications always serve users with the same locale, and that locale
should be equivalent to the default runtime locale of the corresponding programming
environment.
Multilingual applications can determine a user locale dynamically in three ways. Each
method has advantages and disadvantages, but they can be used together in the
applications to complement each other. The user locale can be determined in the
following ways:
■Based on the user profile information from a LDAP directory server such as the
Oracle Internet Directory or other user profile tables stored inside the database
The schema for the user profile should include preferred locale attribute to
indicate the locale of a user. This way of determining a locale user does not work if
a user has not been logged on before.
■Based on the default locale of the browser
Get the default ISO locale setting from a browser. The default ISO locale of the
browser is sent through the Accept-Language HTTP header in every HTTP
request. If the Accept-Language header is NULL, then the desired locale should
default to English. The drawback of this approach is that the Accept-Language
header may not be a reliable source of information for the locale of a user.
■Based on user selection
Allow users to select a locale from a list box or from a menu, and switch the
application locale to the one selected.
The Globalization Development Kit provides an application framework that enables
you to use these locale determination methods declaratively.
Locale Awareness
To be locale-aware or locale-sensitive, Internet applications need to determine the
locale of a user. After the locale of a user is determined, applications should:
■Construct HTML content in the language of the locale
■Use the cultural conventions implied by the locale
Locale-sensitive functions, such as date, time, and monetary formatting, are built into
various programming environments such as Java and PL/SQL. Applications may use
them to format the HTML pages according to the cultural conventions of the locale of
a user. A locale is represented differently in different programming environments. For
example, the French (Canada) locale is represented in different environments as
follows:
■In the ISO standard, it is represented by fr-CA where fr is the language code
defined in the ISO 639 standard and CA is the country code defined in the ISO 3166
standard.
■In Java, it is represented as a Java locale object constructed with fr, the ISO
language code for French, as the language and CA, the ISO country code for
Canada, as the country. The Java locale name is fr_CA.
See Also: "Getting Started with the Globalization Development
Kit" on page 8-7
Getting Started with the Globalization Development Kit
Oracle Globalization Development Kit 8-7
■In PL/SQL and SQL, it is represented mainly by the NLS_LANGUAGE and NLS_
TERRITORY session parameters where the value of the NLS_LANGUAGE parameter
is equal to CANADIAN FRENCH and the value of the NLS_TERRITORY parameter
is equal to CANADA.
If you write applications for more than one programming environment, then locales
must be synchronized between environments. For example, Java applications that call
PL/SQL procedures should map the Java locales to the corresponding NLS_LANGUAGE
and NLS_TERRITORY values and change the parameter values to match the user's
locale before calling the PL/SQL procedures.
The Globalization Development Kit for Java provides a set of Java classes to ensure
consistency on locale-sensitive behaviors with Oracle databases.
Localizing the Content
For the application to support a multilingual environment, it must be able to present
the content in the preferred language and in the locale convention of the user.
Hard-coded user interface text must first be externalized from the application, together
with any image files, so that they can be translated into the different languages
supported by the application. The translation files then must be staged in separate
directories, and the application must be able to locate the relevant content according to
the user locale setting. Special application handling may also be required to support a
fallback mechanism, so that if the user-preferred locale is not available, then the next
most suitable content is presented. For example, if Canadian French content is not
available, then it may be suitable for the application to switch to the French files
instead.
Getting Started with the Globalization Development Kit
The Globalization Development Kit (GDK) for Java provides a J2EE application
framework and Java APIs to develop globalized Internet applications using the best
globalization practices and features designed by Oracle. It reduces the complexities
and simplifies the code that Oracle developers require to develop globalized Java
applications.
GDK for Java complements the existing globalization features in J2EE. Although the
J2EE platform already provides a strong foundation for building globalized
applications, its globalization functionalities and behaviors can be quite different from
Oracle's functionalities. GDK for Java provides synchronization of locale-sensitive
behaviors between the middle-tier Java application and the database server.
GDK for PL/SQL contains a suite of PL/SQL packages that provide additional
globalization functionalities for applications written in PL/SQL.
Figure 8–3 shows the major components of the GDK and how they are related to each
other. User applications run on the J2EE container of Oracle Application Server in the
middle tier. GDK provides the application framework that the J2EE application uses to
simplify coding to support globalization. Both the framework and the application call
the GDK Java API to perform locale-sensitive tasks. GDK for PL/SQL offers PL/SQL
packages that help to resolve globalization issues specific to the PL/SQL environment.
Getting Started with the Globalization Development Kit
8-8 Oracle Database Globalization Support Guide
Figure 8–3 GDK Components
The functionalities offered by GDK for Java can be divided into two categories:
■The GDK application framework for J2EE provides the globalization framework
for building J2EE-based Internet application. The framework encapsulates the
complexity of globalization programming, such as determining user locale,
maintaining locale persistency, and processing locale information. It consists of a
set of Java classes through which applications can gain access to the framework.
These associated Java classes enable applications to code against the framework so
that globalization behaviors can be extended declaratively.
■The GDK Java API offers development support in Java applications and provides
consistent globalization operations as provided in Oracle database servers. The
API is accessible and is independent of the GDK framework so that standalone
Java applications and J2EE applications that are not based on the GDK framework
are able to access the individual features offered by the Java API. The features
provided in the Java API include data and number formatting, sorting, and
handling character sets in the same way as the Oracle Database.
GDK for Java is contained in nine .jar files, all in the form of orai18n*jar. These
files are shipped with the Oracle Database, in the $ORACLE_HOME/jlib directory. If
the application using the GDK is not hosted on the same machine as the database, then
Note: The GDK Java API is certified with JDK versions 1.3 and
later with the following exception: The character set conversion
classes depend on the java.nio.charset package, which is
available in JDK 1.4 and later.
Middle-Tier
Application
Server-Tier
Database
Client-Tier
Browser
GDK
PL / SQL
GDK - Java API
LDAP
GDK
Framework for J2EE
Oracle Application Server
Containers for J2EE
J2EE User
Application
Request
Response
GDK Quick Start
Oracle Globalization Development Kit 8-9
the GDK files must be copied to the application server and included into the
CLASSPATH to run your application. You do not need to install the Oracle Database
into your application server to be able to run the GDK inside your Java application.
GDK is a pure Java library that runs on every platform. The Oracle client parameters
NLS_LANG and ORACLE_HOME are not required.
GDK Quick Start
This section explains how to modify a monolingual application to be a global,
multilingual application using GDK. The subsequent sections in this chapter provide
detailed information on using GDK.
Figure 8–4 shows a screenshot from a monolingual Web application.
Figure 8–4 Original HelloWorld Web Page
The initial, non-GDK HelloWorld Web application simply prints a "Hello World!"
message, along with the current date and time in the top right hand corner of the page.
The following code shows the original HelloWorld JSP source code for the preceding
image.
Example 8–1 HelloWorld JSP Page Code
<%@ page contentType="text/html;charset=windows-1252"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>Hello World Demo</title>
</head>
<body>
<div style="color: blue;" align="right">
<%= new java.util.Date(System.currentTimeMillis()) %>
</div>
<hr/>
<h1>Hello World!</h1>
</body>
</html>
The following code example shows the corresponding Web application descriptor file
for the HelloWorld message.
GDK Quick Start
8-10 Oracle Database Globalization Support Guide
Example 8–2 HelloWorld web.xml Code
<?xml version = '1.0' encoding = 'windows-1252'?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<description>web.xml file for the monolingual Hello World</description>
<session-config>
<session-timeout>35</session-timeout>
</session-config>
<mime-mapping>
<extension>html</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>txt</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
</web-app>
The HelloWorld JSP code in Example 8–1 is only for English-speaking users. Some of
the problems with this code are as follows:
■There is no locale determination based on user preference or browser setting.
■The title and the heading are included in the code.
■The date and time value is not localized based on any locale preference.
■The character encoding included in the code is for Latin-1.
The GDK framework can be integrated into the HelloWorld code to make it a global,
multilingual application. The preceding code can be modified to include the following
features:
■Automatic locale negotiation to detect the user's browser locale and serve the
client with localized HTML pages. The supported application locales are
configured in the GDK configuration file.
■Locale selection list to map the supported application locales. The list can have
application locale display names which are the name of the country representing
the locale. The list will be included on the Web page so users can select a different
locale.
■GDK framework and API for globalization support for the HelloWorld JSP. This
involves selecting display strings in a locale-sensitive manner and formatting the
date and time value.
Modifying the HelloWorld Application
This section explains how to modify the HelloWorld application to support
globalization. The application will be modified to support three locales, Simplified
Chinese (zh-CN), Swiss German (de-CH), and American English (en-US). The
following rules will be used for the languages:
■If the client locale supports one of these languages, then that language will be used
for the application.
■If the client locale does not support one of these languages, then American English
will be used for the application.
GDK Quick Start
Oracle Globalization Development Kit 8-11
In addition, the user will be able to change the language by selecting a supported
locales from the locale selection list. The following tasks describe how to modify the
application:
■Task 1: Enable the Hello World Application to use the GDK Framework
■Task 2: Configure the GDK Framework for Hello World
■Task 3: Enable the JSP or Java Servlet
■Task 4: Create the Locale Selection List
■Task 5: Build the Application
Task 1: Enable the Hello World Application to use the GDK Framework
In this task, the GDK filter and a listener are configured in the Web application
deployment descriptor file, web.xml. This allows the GDK framework to be used with
the HelloWorld application. Example 8–3 shows the GDK-enabled web.xml file.
Example 8–3 The GDK-enabled web.xml File
<?xml version = '1.0' encoding = 'windows-1252'?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<description>web.xml file for Hello World</description>
<!-- Enable the application to use the GDK Application Framework.-->
<filter>
<filter-name>GDKFilter</filter-name>
<filter-class>oracle.i18n.servlet.filter.ServletFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>GDKFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
<listener>
<listener-class>oracle.i18n.servlet.listener.ContextListener</listener-class>
</listener>
<session-config>
<session-timeout>35</session-timeout>
</session-config>
<mime-mapping>
<extension>html</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>txt</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
</web-app>
The following tags were added to the file:
■<filter>
The filter name is GDKFilter, and the filter class is
oracle.i18n.servlet.filter.ServletFilter.
■<filter-mapping>
GDK Quick Start
8-12 Oracle Database Globalization Support Guide
The GDKFilter is specified in the tag, as well as the URL pattern.
■<listener>
The listener class is oracle.i18n.servlet.listener.ContextListener.
The default GDK listener is configured to instantiate GDK ApplicationContext,
which controls application scope operations for the framework.
Task 2: Configure the GDK Framework for Hello World
The GDK application framework is configured with the application configuration file
gdkapp.xml. The configuration file is located in the same directory as the web.xml
file. Example 8–4 shows the gdkapp.xml file.
Example 8–4 GDK Configuration File gdkapp.xml
<?xml version="1.0" encoding="UTF-8"?>
<gdkapp xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="gdkapp.xsd">
<!-- The Hello World GDK Configuration -->
<page-charset default="yes">UTF-8</page-charset>
<!-- The supported application locales for the Hello World Application -->
<application-locales>
<locale>de-CH</locale>
<locale default="yes">en-US</locale>
<locale>zh-CN</locale>
</application-locales>
<locale-determine-rule>
<locale-source>oracle.i18n.servlet.localesource.UserInput</locale-source>
<locale-source>oracle.i18n.servlet.localesource.HttpAcceptLanguage</locale-source>
</locale-determine-rule>
<message-bundles>
<resource-bundle name="default">com.oracle.demo.Messages</resource-bundle>
</message-bundles>
</gdkapp>
The file must be configured for J2EE applications. The following tags are used in the
file:
■<page-charset>
The page encoding tag specifies the character set used for HTTP requests and
responses. The UTF-8 encoding is used as the default because many languages can
be represented by this encoding.
■<application-locales>
Configuring the application locales in the gdkapp.xml file makes a central place
to define locales. This makes it easier to add and remove locales without changing
source code. The locale list can be retrieved using the GDK API call
ApplicationContext.getSupportedLocales.
■<locale-determine-rule>
The language of the initial page is determined by the language setting of the
browser. The user can override this language by choosing from the list. The
GDK Quick Start
Oracle Globalization Development Kit 8-13
locale-determine-rule is used by GDK to first try the Accept-Language
HTTP header as the source of the locale. If the user selects a locale from the list,
then the JSP posts a locale parameter value containing the selected locale. The
GDK then sends a response with the contents in the selected language.
■<message-bundles>
The message resource bundles allow an application access to localized static
content that may be displayed on a Web page. The GDK framework configuration
file allows an application to define a default resource bundle for translated text for
various languages. In the HelloWorld example, the localized string messages are
stored in the Java ListResourceBundle bundle named Messages. The Messages
bundle consists of base resources for the application which are in the default
locale. Two more resource bundles provide the Chinese and German translations.
These resource bundles are named Messages_zh_CN.java and Messages_
de.java respectively. The HelloWorld application will select the right translation
for "Hello World!" from the resource bundle based on the locale determined by the
GDK framework. The <message-bundles> tag is used to configure the resource
bundles that the application will use.
Task 3: Enable the JSP or Java Servlet
JSPs and Java servlets must be enabled to use the GDK API. Example 8–5 shows a JSP
that has been modified to enable to use the GDK API and services. This JSP can
accommodate any language and locale.
Example 8–5 Enabled HelloWorld JSP
. . .
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title><%= localizer.getMessage("helloWorldTitle") %></title>
</head>
<body>
<div style="color: blue;" align="right">
<% Date currDate= new Date(System.currentTimeMillis()); %>
<%=localizer.formatDateTime(currDate, OraDateFormat.LONG)%>
</div>
<hr/>
<div align="left">
<form>
<select name="locale" size="1">
<%= getCountryDropDown(request)%>
</select>
<input type="submit" value="<%= localizer.getMessage("changeLocale") %>">
</input>
</form>
</div>
<h1><%= localizer.getMessage("helloWorld") %></h1>
</body>
</html>
Figure 8–5 shows the HelloWorld application that has been configured with the zh-CN
locale as the primary locale for the browser preference. The HelloWorld string and
page title are displayed in Simplified Chinese. In addition, the date is formatted in the
zh-CN locale convention. This example allows the user to override the locale from the
locale selection list.
GDK Quick Start
8-14 Oracle Database Globalization Support Guide
Figure 8–5 HelloWorld Localized for the zh-CN Locale
When the locale changes or is initialized using the HTTP Request Accept-Language
header or the locale selection list, the GUI behaves appropriately for that locale. This
means the date and time value in the upper right corner is localized properly. In
addition, the strings are localized and displayed on the HelloWorld page.
The GDK Java Localizer class provides capabilities to localize the contents of a Web
page based on the automatic detection of the locale by the GDK framework.
The following code retrieves an instance of the localizer based on the current
HTTPServletRequest object. In addition, several imports are declared for use of the
GDK API within the JSP page. The localizer retrieves localized strings in a
locale-sensitive manner with fallback behavior, and formats the date and time.
<%@page contentType="text/html;charset=UTF-8"%>
<%@page import="java.util.*, oracle.i18n.servlet.*" %>
<%@page import="oracle.i18n.util.*, oracle.i18n.text.*" %>
<%
Localizer localizer = ServletHelper.getLocalizerInstance(request);
%>
The following code retrieves the current date and time value stored in the currDate
variable. The value is formatted by the localizer formatDateTime method. The
OraDateFormat.LONG parameter in the formatDateTime method instructs the
localizer to format the date using the locale's long formatting style. If the locale of the
incoming request is changed to a different locale with the locale selection list, then the
date and time value will be formatted according to the conventions of the new locale.
No code changes need to be made to support newly-introduced locales.
div style="color: blue;" align="right">
<% Date currDate= new Date(System.currentTimeMillis()); %>
<%=localizer.formatDateTime(currDate, OraDateFormat.LONG)%>
</div>
The HelloWorld JSP can be reused for any locale because the HelloWorld string and
title are selected in a locale-sensitive manner. The translated strings are selected from a
resource bundle.
GDK Quick Start
Oracle Globalization Development Kit 8-15
The GDK uses the OraResourceBundle class for implementing the resource bundle
fallback behavior. The following code shows how the Localizer picks the HelloWorld
message from the resource bundle.
The default application resource bundle Messages is declared in the gdkapp.xml file.
The localizer uses the message resource bundle to pick the message and apply the
locale-specific logic. For example, if the current locale for the incoming request is
"de-CH", then the message will first be looked for in the messages_de_CH bundle. If it
does not exist, then it will look up in the Messages_de resource bundle.
<h1><%= localizer.getMessage("helloWorld") %></h1>
Task 4: Create the Locale Selection List
The locale selection list is used to override the selected locale based on the HTTP
Request Accept-Language header. The GDK framework checks the locale parameter
passed in as part of the HTTP POST request as a value for the new locale. A locale
selected with the locale selection list is posted as the locale parameter value. GDK uses
this value for the request locale. All this happens implicitly within the GDK code.
The following code sample displays the locale selection list as an HTML select tag with
the name locale. The submit tag causes the new value to be posted to the server. The
GDK framework retrieves the correct selection.
<form>
<select name="locale" size="1">
<%= getCountryDropDown(request)%>
</select>
<input type="submit" value="<%= localizer.getMessage("changeLocale") %>">
</input>
</form>
The locale selection list is constructed from the HTML code generated by the
getCountryDropDown method. The method converts the configured application
locales into localized country names.
A call is made to the ServletHelper class to get the ApplicationContext object
associated with the current request. This object provides the globalization context for
an application, which includes information such as supported locales and
configuration information. The getSupportedLocales call retrieves the list of
locales in the gdkapp.xml file. The configured application locale list is displayed as
options of the HTML select. The OraDisplayLocaleInfo class is responsible for
providing localization methods of locale-specific elements such as country and
language names.
An instance of this class is created by passing in the current locale automatically
determined by the GDK framework. GDK creates requests and response wrappers for
HTTP request and responses. The request.getLocale() method returns the GDK
determined locale based on the locale determination rules.
The OraDsiplayLocaleInfo.getDisplayCountry method retrieves the localized
country names of the application locales. An HTML option list is created in the
ddOptBuffer string buffer. The getCountryDropDown call returns a string containing
the following HTML values:
<option value="en_US" selected>United States [en_US]</option>
<option value="zh_CN">China [zh_CN]</option>
<option value="de_CH">Switzerland [de_CH]</option>
In the preceding values, the en-US locale is selected for the locale. Country names are
generated are based on the current locale.
GDK Application Framework for J2EE
8-16 Oracle Database Globalization Support Guide
Example 8–6 shows the code for constructing the locale selection list.
Example 8–6 Constructing the Locale Selection List
<%!
public String getCountryDropDown(HttpServletRequest request)
{
StringBuffer ddOptBuffer=new StringBuffer();
ApplicationContext ctx =
ServletHelper.getApplicationContextInstance(request);
Locale[] appLocales = ctx.getSupportedLocales();
Locale currentLocale = request.getLocale();
if (currentLocale.getCountry().equals(""))
{
// Since the Country was not specified get the Default Locale
// (with Country) from the GDK
OraLocaleInfo oli = OraLocaleInfo.getInstance(currentLocale);
currentLocale = oli.getLocale();
}
OraDisplayLocaleInfo odli =
OraDisplayLocaleInfo.getInstance(currentLocale);
for (int i=0;i<appLocales.length; i++)
{
ddOptBuffer.append("<option value=\"" + appLocales[i] + "\"" +
(appLocales[i].getLanguage().equals(currentLocale.getLanguage()) ? "
selected" : "") +
">" + odli.getDisplayCountry(appLocales[i]) +
" [" + appLocales[i] + "]</option>\n");
}
return ddOptBuffer.toString();
}
%>
Task 5: Build the Application
In order to build the application, the following files must be specified in the classpath:
■orai18n.jar
■regexp.jar
The orai18n.jar file contains the GDK framework and the API. The regexp.jar
file contains the regular expression library. The GDK API also has locale determination
capabilities. The classes are supplied by the ora18n-lcsd.jar file.
GDK Application Framework for J2EE
GDK for Java provides the globalization framework for middle-tier J2EE applications.
The framework encapsulates the complexity of globalization programming, such as
determining user locale, maintaining locale persistency, and processing locale
information. This framework minimizes the effort required to make Internet
applications global-ready. The GDK application framework is shown in Figure 8–6.
GDK Application Framework for J2EE
Oracle Globalization Development Kit 8-17
Figure 8–6 GDK Application Framework for J2EE
The main Java classes composing the framework are as follows:
■ApplicationContext provides the globalization context of an application. The
context information includes the list of supported locales and the rule for
determining user-preferred locale. The context information is obtained from the
GDK application configuration file for the application.
■The set of LocaleSource classes can be plugged into the framework. Each
LocaleSource class implements the LocaleSource interface to get the locale
from the corresponding source. Oracle bundles several LocaleSource classes in
GDK. For example, the DBLocaleSource class obtains the locale information of
the current user from a database schema. You can also write a customized
LocaleSource class by implementing the same LocaleSource interface and
plugging it into the framework.
■ServletRequestWrapper and ServletResponseWrapper are the main
classes of the GDK Servlet filter that transforms HTTP requests and HTTP
responses. ServletRequestWrapper instantiates a Localizer object for each
HTTP request based on the information gathered from the
ApplicationContext and LocaleSource objects and ensures that forms
parameters are handled properly. ServletResponseWrapper controls how
HTTP response should be constructed.
■Localizer is the all-in-one object that exposes the important functions that are
sensitive to the current user locale and application context. It provides a
centralized set of methods for you to call and make your applications behave
appropriately to the current user locale and application context.
■The GDK Java API is always available for applications to enable finer control of
globalization behavior.
The GDK application framework simplifies the coding required for your applications
to support different locales. When you write a J2EE application according to the
application framework, the application code is independent of what locales the
application supports, and you control the globalization support in the application by
Request Response
ServletResponseWrapperServletRequestWrapper
Localizer
J2EE User Application
GDK
Configuration
File
GDK Framework for J2EE
ApplicationContext
LocalSource
GDK Java API
GDK Application Framework for J2EE
8-18 Oracle Database Globalization Support Guide
defining it in the GDK application configuration file. There is no code change required
when you add or remove a locale from the list of supported application locales.
The following list gives you some idea of the extent to which you can define the
globalization support in the GDK application configuration file:
■You can add and remove a locale from the list of supported locales.
■You can change the way the user locale is determined.
■You can change the HTML page encoding of your application.
■You can specify how the translated resources can be located.
■You can plug a new LocaleSource object into the framework and use it to detect
a user locale.
This section includes the following topics:
■Making the GDK Framework Available to J2EE Applications
■Integrating Locale Sources into the GDK Framework
■Getting the User Locale From the GDK Framework
■Implementing Locale Awareness Using the GDK Localizer
■Defining the Supported Application Locales in the GDK
■Handling Non-ASCII Input and Output in the GDK Framework
■Managing Localized Content in the GDK
Making the GDK Framework Available to J2EE Applications
The behavior of the GDK application framework for J2EE is controlled by the GDK
application configuration file, gdkapp.xml. The application configuration file allows
developers to specify the behaviors of globalized applications in one centralized place.
One application configuration file is required for each J2EE application using the GDK.
The gdkapp.xml file should be placed in the ./WEB-INF directory of the J2EE
environment of the application. The file dictates the behavior and the properties of the
GDK framework and the application that is using it. It contains locale mapping tables,
character sets of content files, and globalization parameters for the configuration of the
application. The application administrator can modify the application configuration
file to change the globalization behavior in the application, without needing to change
the programs and to recompile them.
For a J2EE application to use the GDK application framework defined by the
corresponding GDK application configuration file, the GDK Servlet filter and the GDK
context listener must be defined in the web.xml file of the application. The web.xml
file should be modified to include the following at the beginning of the file:
<web-app>
<!-- Add GDK filter that is called after the authentication -->
<filter>
<filter-name>gdkfilter</filter-name>
<filter-class>oracle.i18n.servlet.filter.ServletFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>gdkfilter</filter-name>
<url-pattern>*.jsp</url-pattern>
See Also: "The GDK Application Configuration File" on page 8-35
GDK Application Framework for J2EE
Oracle Globalization Development Kit 8-19
</filter-mapping>
<!-- Include the GDK context listener -->
<listener>
<listener-class>oracle.i18n.servlet.listener.ContextListener</listener-class>
</listener>
</web-app>
Examples of the gdkapp.xml and web.xml files can be found in the $ORACLE_
HOME/nls/gdk/demo directory.
The GDK application framework supports Servlet container version 2.3 and later. It
uses the Servlet filter facility for transparent globalization operations such as
determining the user locale and specifying the character set for content files. The
ContextListener instantiates GDK application parameters described in the GDK
application configuration file. The ServletFilter overrides the request and
response objects with a GDK request (ServletRequestWrapper) and response
(ServletResponseWrapper) objects, respectively.
If other application filters are used in the application to also override the same
methods, then the filter in the GDK framework may return incorrect results. For
example, if getLocale returns en_US, but the result is overridden by other filters,
then the result of the GDK locale detection mechanism is affected. All of the methods
that are being overridden in the filter of the GDK framework are documented in Oracle
Globalization Development Kit Java API Reference. Be aware of potential conflicts when
using other filters together with the GDK framework.
Integrating Locale Sources into the GDK Framework
Determining the user's preferred locale is the first step in making an application
global-ready. The locale detection offered by the J2EE application framework is
primitive. It lacks the method that transparently retrieves the most appropriate user
locale among locale sources. It provides locale detection by the HTTP language
preference only, and it cannot support a multilevel locale fallback mechanism. The
GDK application framework provides support for predefined locale sources to
complement J2EE. In a web application, several locale sources are available. Table 8–1
summarizes locale sources that are provided by the GDK.
Table 8–1 Locale Resources Provided by the GDK
Locale Description
HTTP language preference Locales included in the HTTP protocol as a value of Accept-Language. This is set
at the web browser level. A locale fallback operation is required if the browser
locale is not supported by the application.
User input locale Locale specified by the user from a menu or a parameter in the HTTP protocol
User profile locale preference
from database Locale preference stored in the database as part of the user profiles
Application default locale A locale defined in the GDK application configuration file. This locale is defined as
the default locale for the application. Typically, this is used as a fallback locale
when the other locale sources are not available.
See Also: "The GDK Application Configuration File" on page 8-35
for information about the GDK multilevel locale fallback
mechanism
GDK Application Framework for J2EE
8-20 Oracle Database Globalization Support Guide
The GDK application framework provides seamless support for predefined locale
sources, such as user input locale, HTTP language preference, user profile locale
preference in the database, and the application default locale. You can incorporate the
locale sources to the framework by defining them under the
<locale-determine-rule> tag in the GDK application configuration file as
follows:
<locale-determine-rule>
<locale-source>oracle.i18n.servlet.localesource.UserInput</locale-source>
<locale-source>oracle.i18n.servlet.localesource.HTTPAcceptLanguage</locale-source>
</locale-determine-rule>
The GDK framework uses the locale source declaration order and determines whether
a particular locale source is available. If it is available, then it is used as the source,
otherwise, it tries to find the next available locale source for the list. In the preceding
example, if the UserInput locale source is available, it is used first, otherwise, the
HTTPAcceptLanguage locale source will be used.
Custom locale sources, such as locale preference from an LDAP server, can be easily
implemented and integrated into the GDK framework. You need to implement the
LocaleSource interface and specify the corresponding implementation class under
the <locale-determine-rule> tag in the same way as the predefined locale
sources were specified.
The LocaleSource implementation not only retrieves the locale information from the
corresponding source to the framework but also updates the locale information to the
corresponding source when the framework tells it to do so. Locale sources can be
read-only or read/write, and they can be cacheable or noncacheable. The GDK
framework initiates updates only to read/write locale sources and caches the locale
information from cacheable locale sources. Examples of custom locale sources can be
found in the $ORACLE_HOME/nls/gdk/demo directory.
Getting the User Locale From the GDK Framework
The GDK offers automatic locale detection to determine the current locale of the user.
For example, the following code retrieves the current user locale in Java. It uses a
Locale object explicitly.
Locale loc = request.getLocale();
The getLocale() method returns the Locale that represents the current locale. This
is similar to invoking the HttpServletRequest.getLocale() method in JSP or
Java Servlet code. However, the logic in determining the user locale is different,
because multiple locale sources are being considered in the GDK framework.
Alternatively, you can get a Localizer object that encapsulates the Locale object
determined by the GDK framework. For the benefits of using the Localizer object,
see "Implementing Locale Awareness Using the GDK Localizer" on page 8-21.
Localizer localizer = ServletHelper.getLocalizerInstance(request);
Locale loc = localizer.getLocale();
The locale detection logic of the GDK framework depends on the locale sources
defined in the GDK application configuration file. The names of the locale sources are
registered in the application configuration file. The following example shows the
locale determination rule section of the application configuration file. It indicates that
the user-preferred locale can be determined from either the LDAP server or from the
See Also: Oracle Globalization Development Kit Java API Reference
for more information about implementing a LocaleSource
GDK Application Framework for J2EE
Oracle Globalization Development Kit 8-21
HTTP Accept-Language header. The LDAPUserSchema locale source class should
be provided by the application. Note that all of the locale source classes have to be
extended from the LocaleSource abstract class.
<locale-determine-rule>
<locale-source>LDAPUserSchema</locale-source>
<locale-source>oracle.i18n.localesource.HTTPAcceptLanguage</locale-source>
</locale-determine-rule>
For example, when the user is authenticated in the application and the user locale
preference is stored in an LDAP server, then the LDAPUserSchema class connects to
the LDAP server to retrieve the user locale preference. When the user is anonymous,
then the HttpAcceptLanguage class returns the language preference of the web
browser.
The cache is maintained for the duration of a HTTP session. If the locale source is
obtained from the HTTP language preference, then the locale information is passed to
the application in the HTTP Accept-Language header and not cached. This enables
flexibility so that the locale preference can change between requests. The cache is
available in the HTTP session.
The GDK framework exposes a method for the application to overwrite the locale
preference information persistently stored in locale sources such as the LDAP server or
the user profile table in the database. This method also resets the current locale
information stored inside the cache for the current HTTP session. The following is an
example of overwriting the preferred locale using the store command.
<input type="hidden"
name="<%=appctx.getParameterName(LocaleSource.Parameter.COMMAND)%>"
value="store">
To discard the current locale information stored inside the cache, the clean command
can be specified as the input parameter. The following table shows the list of
commands supported by the GDK:
Note that the GDK parameter names can be customized in the application
configuration file to avoid name conflicts with other parameters used in the
application.
Implementing Locale Awareness Using the GDK Localizer
The Localizer object obtained from the GDK application framework is an all-in-one
globalization object that provides access to functions that are commonly used in
building locale awareness in your applications. In addition, it provides functions to get
information about the application context, such as the list of supported locales. The
Localizer object simplifies and centralizes the code required to build consistent
locale awareness behavior in your applications.
The oracle.i18n.servlet package contains the Localizer class. You can get the
Localizer instance as follows:
Localizer lc = ServletHelper.getLocalizerInstance(request);
Command Functionality
store Updates user locale preferences in the available locale sources with the
specified locale information. This command is ignored by the read-only
locale sources.
clean Discards the current locale information in the cache.
GDK Application Framework for J2EE
8-22 Oracle Database Globalization Support Guide
The Localizer object encapsulates the most commonly used locale-sensitive
information determined by the GDK framework and exposes it as locale-sensitive
methods. This object includes the following functionalities pertaining to the user
locale:
■Format date in long and short formats
■Format numbers and currencies
■Get collation key value of a string
■Get locale data such as language, country and currency names
■Get locale data to be used for constructing user interface
■Get a translated message from resource bundles
■Get text formatting information such as writing direction
■Encode and decode URLs
■Get the common list of time zones and linguistic sorts
For example, when you want to display a date in your application, you may want to
call the Localizer.formatDate() or Localizer.formateDateTime()
methods. When you want to determine the writing direction of the current locale, you
can call the Localizer.getWritingDirection() and
Localizer.getAlignment() to determine the value used in the <DIR> tag and
<ALIGN> tag respectively.
The Localizer object also exposes methods to enumerate the list of supported
locales and their corresponding languages and countries in your applications.
The Localizer object actually makes use of the classes in the GDK Java API to
accomplish its tasks. These classes include, but are not limited to, the following:
OraDateFormat, OraNumberFormat, OraCollator, OraLocaleInfo,
oracle.i18n.util.LocaleMapper, oracle.i18n.net.URLEncoder, and
oracle.i18n.net.URLDecoder.
The Localizer object simplifies the code you need to write for locale awareness. It
maintains caches of the corresponding objects created from the GDK Java API so that
the calling application does not need to maintain these objects for subsequent calls to
the same objects. If you require more than the functionality the Localizer object can
provide, then you can always call the corresponding methods in the GDK Java API
directly.
Defining the Supported Application Locales in the GDK
The number of locales and the names of the locales that an application needs to
support are based on the business requirements of the application. The names of the
locales that are supported by the application are registered in the application
configuration file. The following example shows the application locales section of the
application configuration file. It indicates that the application supports German (de),
Japanese (ja), and English for the US (en-US), with English defined as the default
fallback application locale. Note that the locale names are based on the IANA
convention.
<application-locales>
<locale>de</locale>
See Also: Oracle Globalization Development Kit Java API Reference
for detailed information about the Localizer object
GDK Application Framework for J2EE
Oracle Globalization Development Kit 8-23
<locale>ja</locale>
<locale default="yes">en-US</locale>
</application-locales>
When the GDK framework detects the user locale, it verifies whether the locale that is
returned is one of the supported locales in the application configuration file. The
verification algorithm is as follows:
1. Retrieve the list of supported application locales from the application
configuration file.
2. Check whether the locale that was detected is included in the list. If it is included
in the list, then use this locale as the current client's locale.
3. If there is a variant in the locale that was detected, then remove the variant and
check whether the resulting locale is in the list. For example, the Java locale de_
DE_EURO has a EURO variant. Remove the variant so that the resulting locale is
de_DE.
4. If the locale includes a country code, then remove the country code and check
whether the resulting locale is in the list. For example, the Java locale de_DE has a
country code of DE. Remove the country code so that the resulting locale is de.
5. If the detected locale does not match any of the locales in the list, then use the
default locale that is defined in the application configuration file as the client
locale.
By performing steps 3 and 4, the application can support users with the same language
requirements but with different locale settings than those defined in the application
configuration file. For example, the GDK can support de-AT (the Austrian variant of
German), de-CH (the Swiss variant of German), and de-LU (the Luxembourgian
variant of German) locales.
The locale fallback detection in the GDK framework is similar to that of the Java
Resource Bundle, except that it is not affected by the default locale of the Java VM.
This exception occurs because the Application Default Locale can be used during the
GDK locale fallback operations.
If the application-locales section is omitted from the application configuration file,
then the GDK assumes that the common locales, which can be returned from the
OraLocaleInfo.getCommonLocales method, are supported by the application.
Handling Non-ASCII Input and Output in the GDK Framework
The character set (or character encoding) of an HTML page is a very important piece of
information to a browser and an Internet application. The browser needs to interpret
this information so that it can use correct fonts and character set mapping tables for
displaying pages. The Internet applications need to know so they can safely process
input data from a HTML form based on the specified encoding.
The page encoding can be translated as the character set used for the locale to which
an Internet application is serving.
In order to correctly specify the page encoding for HTML pages without using the
GDK framework, Internet applications must:
1. Determine the desired page input data character set encoding for a given locale.
2. Specify the corresponding encoding name for each HTTP request and HTTP
response.
GDK Application Framework for J2EE
8-24 Oracle Database Globalization Support Guide
Applications using the GDK framework can ignore these steps. No application code
change is required. The character set information is specified in the GDK application
configuration file. At runtime, the GDK automatically sets the character sets for the
request and response objects. The GDK framework does not support the scenario
where the incoming character set is different from that of the outgoing character set.
The GDK application framework supports the following scenarios for setting the
character sets of the HTML pages:
■A single local character set is dedicated to the whole application. This is
appropriate for a monolingual Internet application. Depending on the properties
of the character set, it may be able to support more than one language. For
example, most Western European languages can be served by ISO-8859-1.
■Unicode UTF-8 is used for all contents regardless of the language. This is
appropriate for a multilingual application that uses Unicode for deployment.
■The native character set for each language is used. For example, English contents
are represented in ISO-8859-1, and Japanese contents are represented in Shift_JIS.
This is appropriate for a multilingual Internet application that uses a default
character set mapping for each locale. This is useful for applications that need to
support different character sets based on the user locales. For example, for mobile
applications that lack Unicode fonts or Internet browsers that cannot fully support
Unicode, the character sets must to be determined for each request.
The character set information is specified in the GDK application configuration file.
The following is an example of setting UTF-8 as the character set for all the application
pages.
<page-charset>UTF-8</page-charset>
The page character set information is used by the ServletRequestWrapper class,
which sets the proper character set for the request object. It is also used by the
ContentType HTTP header specified in the ServletResponseWrapper class for
output when instantiated. If page-charset is set to AUTO-CHARSET, then the
character set is assumed to be the default character set for the current user locale. Set
page-charset to AUTO-CHARSET as follows:
<page-charset>AUTO-CHARSET</page-charset>
The default mappings are derived from the LocaleMapper class, which provides the
default IANA character set for the locale name in the GDK Java API.
Table 8–2 lists the mappings between the common ISO locales and their IANA
character sets.
Table 8–2 Mapping Between Common ISO Locales and IANA Character Sets
ISO Locale NLS_LANGUAGE Value NLS_TERRITORY Value IANA Character Set
ar-SA ARABIC SAUDI ARABIA WINDOWS-1256
de-DE GERMAN GERMANY WINDOWS-1252
en-US AMERICAN AMERICA WINDOWS-1252
en-GB ENGLISH UNITED KINGDOM WINDOWS-1252
el GREEK GREECE WINDOWS-1253
es-ES SPANISH SPAIN WINDOWS-1252
fr FRENCH FRANCE WINDOWS-1252
fr-CA CANADIAN FRENCH CANADA WINDOWS-1252
GDK Application Framework for J2EE
Oracle Globalization Development Kit 8-25
The locale to character set mapping in the GDK can also be customized. To override
the default mapping defined in the GDK Java API, a locale-to-character-set mapping
table can be specified in the application configuration file.
<locale-charset-maps>
<locale-charset>
<locale>ja</locale><charset>EUC-JP</charset>
</locale-charset>
</locale-charset-maps>
The previous example shows that for locale Japanese (ja), the GDK changes the
default character set from SHIFT_JIS to EUC-JP.
Managing Localized Content in the GDK
This section includes the following topics:
■Managing Localized Content in JSPs and Java Servlets
■Managing Localized Content in Static Files
Managing Localized Content in JSPs and Java Servlets
Resource bundles enable access to localized contents at runtime in J2SE. Translatable
strings within Java servlets and Java Server Pages (JSPs) are externalized into Java
resource bundles so that these resource bundles can be translated independently into
different languages. The translated resource bundles carry the same base class names
as the English bundles, using the Java locale name as the suffix.
To retrieve translated data from the resource bundle, the getBundle() method must
be invoked for every request.
<% Locale user_locale=request.getLocale();
ResourceBundle rb=ResourceBundle.getBundle("resource",user_locale); %>
<%= rb.getString("Welcome") %>
The GDK framework simplifies the retrieval of text strings from the resource bundles.
Localizer.getMessage() is a wrapper to the resource bundle.
iw HEBREW ISRAEL WINDOWS-1255
ko KOREAN KOREA EUC-KR
ja JAPANESE JAPAN SHIFT_JIS
it ITALIAN ITALY WINDOWS-1252
pt PORTUGUESE PORTUGAL WINDOWS-1252
pt-BR BRAZILIAN
PORTUGUESE BRAZIL WINDOWS-1252
tr TURKISH TURKEY WINDOWS-1254
nl DUTCH THE NETHERLANDS WINDOWS-1252
zh SIMPLIFIED CHINESE CHINA GBK
zh-TW TRADITIONAL CHINESE TAIWAN BIG5
See Also: "Oracle Locale Information in the GDK" on page 8-28
Table 8–2 (Cont.) Mapping Between Common ISO Locales and IANA Character Sets
ISO Locale NLS_LANGUAGE Value NLS_TERRITORY Value IANA Character Set
GDK Application Framework for J2EE
8-26 Oracle Database Globalization Support Guide
<% Localizer.getMessage ("Welcome") %>
Instead of specifying the base class name as getBundle() in the application, you can
specify the resource bundle in the application configuration file, so that the GDK
automatically instantiates a ResourceBundle object when a translated text string is
requested.
<message-bundles>
<resource-bundle name="default">resource</resource-bundle>
</message-bundles>
This configuration file snippet declares a default resource bundle whose translated
contents reside in the "resource" Java bundle class. Multiple resource bundles can be
specified in the configuration file. To access a nondefault bundle, specify the name
parameter in the getMessage method. The message bundle mechanism uses the
OraResourceBundle GDK class for its implementation. This class provides the
special locale fallback behaviors on top of the Java behaviors. The rules are as follows:
■If the given locale exactly matches the locale in the available resource bundles, it
will be used.
■If the resource bundle for Chinese in Singapore (zh_SG) is not found, it will fall
back to the resource bundle for Chinese in China (zh_CN) for Simplified Chinese
translations.
■If the resource bundle for Chinese in Hong Kong (zh_HK) is not found, it will fall
back to the resource bundle for Chinese in Taiwan (zh_TW) for Traditional Chinese
translations.
■If the resource bundle for Chinese in Macau (zh_MO) is not found, it will fall back
to the resource bundle for Chinese in Taiwan (zh_TW) for Traditional Chinese
translations.
■If the resource bundle for any other Chinese (zh_ and zh) is not found, it will fall
back to the resource bundle for Chinese in China (zh_CN) for Simplified Chinese
translations.
■The default locale, which can be obtained by the Locale.getDefault()
method, will not be considered in the fallback operations.
For example, assume the default locale is ja_JP and the resource handle for it is
available. When the resource bundle for es_MX is requested, and neither resource
bundle for es or es_MX is provided, the base resource bundle object that does not have
a local suffix is returned.
The usage of the OraResourceBundle class is similar to the
java.util.ResourceBundle class, but the OraResearchBundle class does not
instantiate itself. Instead, the return value of the getBundle method is an instance of
the subclass of the java.util.ResourceBundle class.
Managing Localized Content in Static Files
For a application, which supports only one locale, the URL that has a suffix of
/index.html typically takes the user to the starting page of the application.
In a globalized application, contents in different languages are usually stored
separately, and it is common for them to be staged in different directories or with
different file names based on the language or the country name. This information is
then used to construct the URLs for localized content retrieval in the application.
The following examples illustrate how to retrieve the French and Japanese versions of
the index page. Their suffixes are as follows:
GDK Java API
Oracle Globalization Development Kit 8-27
/fr/index.html
/ja/index.html
By using the rewriteURL() method of the ServletHelper class, the GDK
framework handles the logic to locate the translated files from the corresponding
language directories. The ServletHelper.rewriteURL() method rewrites a URL
based on the rules specified in the application configuration file. This method is used
to determine the correct location where the localized content is staged.
The following is an example of the JSP code:
<img src="<%="ServletHelper.rewriteURL("image/welcome.jpg", request)%>">
<a href="<%="ServletHelper.rewriteURL("html/welcome.html", request)%>">
The URL rewrite definitions are defined in the GDK application configuration file:
<url-rewrite-rule fallback="yes">
<pattern>(.*)/(a-zA-Z0-9_\]+.)$</pattern>
<result>$1/$A/$2</result>
</url-rewrite-rule>
The pattern section defined in the rewrite rule follows the regular expression
conventions. The result section supports the following special variables for replacing:
■$L is used to represent the ISO 639 language code part of the current user locale
■$C represents the ISO 3166 country code
■$A represents the entire locale string, where the ISO 639 language code and ISO
3166 country code are connected with an underscore character (_)
■$1 to $9 represent the matched substrings
For example, if the current user locale is ja, then the URL for the welcome.jpg
image file is rewritten as image/ja/welcome.jpg, and welcome.html is changed
to html/ja/welcome.html.
Both ServletHelper.rewriteURL()and Localizer.getMessage() methods
perform consistent locale fallback operations in the case where the translation files for
the user locale are not available. For example, if the online help files are not available
for the es_MX locale (Spanish for Mexico), but the es (Spanish for Spain) files are
available, then the methods will select the Spanish translated files as the substitute.
GDK Java API
The globalization features and behaviors in Java are not the same as those offered in
Oracle Database. For example, J2SE supports a set of locales and character sets that are
different from locales and character sets in Oracle Database. This inconsistency can be
confusing for users when their application contains data that is formatted based on
two different conventions. For example, dates that are retrieved from the database are
formatted using Oracle conventions, such as number and date formatting and
linguistic sort ordering. However, the static application data is typically formatted
using Java locale conventions. The globalization functionalities in Java can also be
different depending on the version of the JDK on which the application runs.
Before Oracle Database 10g, when an application was required to incorporate Oracle
globalization features, it had to make connections to the database and issue SQL
statements. Such operations make the application complicated and generate more
network connections to the database.
GDK Java API
8-28 Oracle Database Globalization Support Guide
In Oracle Database 10g and later, the GDK Java API extends the globalization features
to the middle tier. By enabling applications to perform globalization logic such as
Oracle date and number formatting and linguistic sorting in the middle tier, the GDK
Java API enables developers to eliminate expensive programming logic in the
database. The GDK Java API also provides standard compliance for XQuery. This
improves the overall application performance by reducing the database processing
load, and by decreasing unnecessary network traffic between the application tier and
the backend.
The GDK Java API also offers advanced globalization features, such as language and
character set detection, and the enumeration of common locale data for a territory or a
language (for example, all time zones supported in Canada). These features are not
available in most programming platforms. Without the GDK Java API, developers
must write business logic to handle these processes inside the application.
The key functionalities of the GDK Java API are as follows:
■Oracle Locale Information in the GDK
■Oracle Locale Mapping in the GDK
■Oracle Character Set Conversion (JDK 1.4 and Later) in the GDK
■Oracle Date, Number, and Monetary Formats in the GDK
■Oracle Binary and Linguistic Sorts in the GDK
■Oracle Language and Character Set Detection in the GDK
■Oracle Translated Locale and Time Zone Names in the GDK
■Using the GDK with E-Mail Programs
Oracle Locale Information in the GDK
Oracle locale definitions, which include languages, territories, linguistic sorts, and
character sets, are exposed in the GDK Java API. The naming convention that Oracle
uses may be different from other vendors. Although many of these names and
definitions follow industry standards, some are Oracle-specific, tailored to meet
special customer requirements.
OraLocaleInfois an Oracle locale class that includes language, territory, and collator
objects. It provides a method for applications to retrieve a collection of locale-related
objects for a given locale. Examples include: a full list of the Oracle linguistic sorts
available in the GDK, the local time zones defined for a given territory, or the common
languages used in a particular territory.
Following are examples of using the OraLocaleInfo class:
// All Territories supported by GDK
String[] avterr = OraLocaleInfo.getAvailableTerritories();
// Local TimeZones for a given Territory
OraLocaleInfo oloc = OraLocaleInfo.getInstance("English", "Canada");
TimeZone[] loctz = oloc.getLocalTimeZones();
Oracle Locale Mapping in the GDK
The GDK Java API provides the LocaleMapper class. It maps equivalent locales and
character sets between Java, IANA, ISO, and Oracle. A Java application may receive
locale information from the client that is specified in an Oracle Database locale name
GDK Java API
Oracle Globalization Development Kit 8-29
or an IANA character set name. The Java application must be able to map to an
equivalent Java locale or Java encoding before it can process the information correctly.
The follow example shows using the LocaleMapper class.
// Mapping from Java locale to Oracle language and Oracle territory
Locale locale = new Locale("it", "IT");
String oraLang = LocaleMapper.getOraLanguage(locale);
String oraTerr = LocaleMapper.getOraTerritory(locale);
// From Oracle language and Oracle territory to Java Locale
locale = LocaleMapper.getJavaLocale("AMERICAN","AMERICA");
locale = LocaleMapper.getJavaLocale("TRADITONAL CHINESE", "");
// From IANA & Java to Oracle Character set
String ocs1 = LocaleMapper.getOraCharacterSet(
LocaleMapper.IANA, "ISO-8859-1");
String ocs2 = LocaleMapper.getOraCharacterSet(
LocaleMapper.JAVA, "ISO8859_1");
The LocaleMapper class can also return the most commonly used e-mail character
set for a specific locale on both Windows and UNIX platforms. This is useful when
developing Java applications that need to process e-mail messages.
Oracle Character Set Conversion (JDK 1.4 and Later) in the GDK
The GDK Java API contains a set of character set conversion classes APIs that enable
users to perform Oracle character set conversions. Although Java JDK is already
equipped with classes that can perform conversions for many of the standard
character sets, they do not support Oracle-specific character sets and Oracle's
user-defined character sets.
In JDK 1.4, J2SE introduced an interface for developers to extend Java's character sets.
The GDK Java API provides implicit support for Oracle's character sets by using this
plug-in feature. You can access the J2SE API to obtain Oracle-specific behaviors.
Figure 8–7 shows that the GDK character set conversion tables are plugged into J2SE in
the same way as the Java character set tables. With this pluggable framework of J2SE,
the Oracle character set conversions can be used in the same way as other Java
character set conversions.
Figure 8–7 Oracle Character Set Plug-In
See Also: "Using the GDK with E-Mail Programs" on page 8-34
J2SE
Runtime
Java character set
conversion table
GDK character set
conversion table
GDK Java API
8-30 Oracle Database Globalization Support Guide
Because the java.nio.charset Java package is not available in JDK versions before
1.4, you must install JDK 1.4 or later to use Oracle's character set plug-in feature.
The GDK character conversion classes support all Oracle character sets including
user-defined characters sets. It can be used by Java applications to properly convert to
and from Java's internal character set, UTF-16.
Oracle's character set names are proprietary. To avoid potential conflicts with Java's
own character sets, all Oracle character set names have an X-ORACLE- prefix for all
implicit usage through Java's API.
The following is an example of Oracle character set conversion:
// Converts the Chinese character "three" from UCS2 to JA16SJIS
String str = "\u4e09";
byte[] barr = str.getBytes("x-oracle-JA16SJIS");
Just as with other Java character sets, the character set facility in
java.nio.charset.Charset is applicable to all of the Oracle character sets. For
example, if you wish to check whether the specified character set is a superset of
another character set, then you can use the Charset.contains method as follows:
Charset cs1 = Charset.forName("x-oracle-US7ASCII");
Charset cs2 = Charset.forName("x-oracle-WE8WINDOWS1252");
// true if WE8WINDOWS1252 is the superset of US7ASCII, otherwise false.
boolean osc = cs2.contains(cs1);
For a Java application that is using the JDBC driver to communicate with the database,
the JDBC driver provides the necessary character set conversion between the
application and the database. Calling the GDK character set conversion methods
explicitly within the application is not required. A Java application that interprets and
generates text files based on Oracle's character set encoding format is an example of
using Oracle character set conversion classes.
Oracle Date, Number, and Monetary Formats in the GDK
The GDK Java API provides formatting classes that support date, number, and
monetary formats using Oracle conventions for Java applications in the
oracle.i18n.text package.
New locale formats introduced in Oracle Database 10g, such as the short and long
date, number, and monetary formats, are also exposed in these format classes.
The following are examples of Oracle date, Oracle number, and Oracle monetary
formatting:
// Obtain the current date and time in the default Oracle LONG format for
// the locale de_DE (German_Germany)
Locale locale = new Locale("de", "DE");
OraDateFormat odf =
OraDateFormat.getDateTimeInstance(OraDateFormat.LONG, locale);
// Obtain the numeric value 1234567.89 using the default number format
// for the Locale en_IN (English_India)
locale = new Locale("en", "IN");
OraNumberFormat onf = OraNumberFormat.getNumberInstance(locale);
String nm = onf.format(new Double(1234567.89));
GDK Java API
Oracle Globalization Development Kit 8-31
// Obtain the monetary value 1234567.89 using the default currency
// format for the Locale en_US (American_America)
locale = new Locale("en", "US");
onf = OraNumberFormat.getCurrencyInstance(locale);
nm = onf.format(new Double(1234567.89));
Oracle Binary and Linguistic Sorts in the GDK
Oracle provides support for binary, monolingual, and multilingual linguistic sorts in
the database. In Oracle Database, these sorts provide case-insensitive and
accent-insensitive sorting and searching capabilities inside the database. By using the
OraCollator class, the GDK Java API enables Java applications to sort and search for
information based on the latest Oracle binary and linguistic sorting features, including
case-insensitive and accent-insensitive options.
Normalization can be an important part of sorting. The composition and
decomposition of characters are based on the Unicode standard; therefore, sorting also
depends on the Unicode standard. The GDK contains methods to perform
composition.
The sorting order of a binary sort is based on the Oracle character set that is being
used. Except for the UTFE character set, the binary sorts of all Oracle character sets are
supported in the GDK Java API. The only linguistic sort that is not supported in the
GDK Java API is JAPANESE, but a similar and more accurate sorting result can be
achieved by using JAPANESE_M.
The following example shows string comparisons and string sorting.
Example 8–7 String Comparisons and String Sorting
// compares strings using XGERMAN
private static String s1 = "abcSS";
private static String s2 = "abc\u00DF";
String cname = "XGERMAN";
OraCollator ocol = OraCollator.getInstance(cname);
int c = ocol.compare(s1, s2);
// sorts strings using GENERIC_M
private static String[] source =
new String[]
{
"Hochgeschwindigkeitsdrucker",
"Bildschirmfu\u00DF",
"Skjermhengsel",
"DIMM de Mem\u00F3ria",
"M\u00F3dulo SDRAM com ECC",
};
Note: Because each version of the JDK may support a different
version of the Unicode standard, the GDK provides an OraNormalizer
class that is based on the latest version of the standard, which for this
release is Unicode 5.0.
GDK Java API
8-32 Oracle Database Globalization Support Guide
cname = "GENERIC_M";
ocol = OraCollator.getInstance(cname);
List result = getCollationKeys(source, ocol);
private static List getCollationKeys(String[] source, OraCollator ocol)
{
List karr = new ArrayList(source.length);
for (int i = 0; i < source.length; ++i)
{
karr.add(ocol.getCollationKey(source[i]));
}
Collections.sort(karr); // sorting operation
return karr;
}
Oracle Language and Character Set Detection in the GDK
The Oracle Language and Character Set Detection Java classes in the GDK Java API
provide a high performance, statistically based engine for determining the character
set and language for unspecified text. It can automatically identify language and
character set pairs from throughout the world. With each text, the language and
character set detection engine sets up a series of probabilities, each probability
corresponding to a language and character set pair. The most probable pair statistically
identifies the dominant language and character set.
The purity of the text submitted affects the accuracy of the language and character set
detection. Only plain text strings are accepted, so any tagging needs to be stripped
before hand. The ideal case is literary text with almost no foreign words or
grammatical errors. Text strings that contain a mix of languages or character sets, or
nonnatural language text like addresses, phone numbers, and programming language
code may yield poor results.
The LCSDetector class can detect the language and character set of a byte array, a
character array, a string, and an InputStream class. It supports both plain text and
HTML file detection. It can take the entire input for sampling or only portions of the
input for sampling, when the length or both the offset and the length are supplied. For
each input, up to three potential language and character set pairs can be returned by
the LCSDetector class. They are always ranked in sequence, with the pair with the
highest probability returned first.
The following are examples of using the LCSDetector class to enable language and
character set detection:
// This example detects the character set of a plain text file "foo.txt" and
// then appends the detected ISO character set name to the name of the text file
LCSDetector lcsd = new LCSDetector();
File oldfile = new File("foo.txt");
FileInputStream in = new FileInputStream(oldfile);
lcsd.detect(in);
String charset = lcsd.getResult().getIANACharacterSet();
File newfile = new File("foo."+charset+".txt");
oldfile.renameTo(newfile);
See Also: "Language and Character Set Detection Support" on
page A-18 for a list of supported language and character set pairs
GDK Java API
Oracle Globalization Development Kit 8-33
// This example shows how to use the LCSDector class to detect the language and
// character set of a byte array
int offset = 0;
LCSDetector led = new LCSDetector();
/* loop through the entire byte array */
while ( true )
{
bytes_read = led.detect(byte_input, offset, 1024);
if ( bytes_read == -1 )
break;
offset += bytes_read;
}
LCSDResultSet res = led.getResult();
/* print the detection results with close ratios */
System.out.println("the best guess " );
System.out.println("Langauge " + res.getOraLanguage() );
System.out.println("CharacterSet " + res.getOraCharacterSet() );
int high_hit = res.getHiHitPairs();
if ( high_hit >= 2 )
{
System.out.println("the second best guess " );
System.out.println("Langauge " + res.getOraLanguage(2) );
System.out.println("CharacterSet " +res.getOraCharacterSet(2) );
}
if ( high_hit >= 3 )
{
System.out.println("the third best guess ");
System.out.println("Langauge " + res.getOraLanguage(3) );
System.out.println("CharacterSet " +res.getOraCharacterSet(3) );
}
Oracle Translated Locale and Time Zone Names in the GDK
All of the Oracle language names, territory names, character set names, linguistic sort
names, and time zone names have been translated into 27 languages including
English. They are readily available for inclusion into the user applications, and they
provide consistency for the display names across user applications in different
languages. OraDisplayLocaleInfo is a utility class that provides the translations of
locale and attributes. The translated names are useful for presentation in user interface
text and for drop-down selection boxes. For example, a native French speaker prefers
to select from a list of time zones displayed in French than in English.
The following example shows using OraDisplayLocaleInfo to return a list of time
zones supported in Canada, using the French translation names.
Example 8–8 Using OraDisplayLocaleInfo to Return a Specific List of Time Zones
OraLocaleInfo oloc = OraLocaleInfo.getInstance("CANADIAN FRENCH", "CANADA");
OraDisplayLocaleInfo odloc = OraDisplayLocaleInfo.getInstance(oloc);
TimeZone[] loctzs = oloc.getLocaleTimeZones();
String [] disptz = new string [loctzs.length];
for (int i=0; i<loctzs.length; ++i)
{
disptz [i]= odloc.getDisplayTimeZone(loctzs[i]);
...
}
GDK Java API
8-34 Oracle Database Globalization Support Guide
Using the GDK with E-Mail Programs
You can use the GDK LocaleMapper class to retrieve the most commonly used e-mail
character set. Call LocaleMapper.getIANACharSetFromLocale, passing in the
locale object. The return value is an array of character set names. The first character set
returned is the most commonly used e-mail character set.
The following example illustrates sending an e-mail message containing Simplified
Chinese data in the GBK character set encoding.
Example 8–9 Sending E-mail Containing Simplified Chinese Data in GBK Character Set
Encoding
import oracle.i18n.util.LocaleMapper;
import java.util.Date;
import java.util.Locale;
import java.util.Properties;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeUtility;
/**
* Email send operation sample
*
* javac -classpath orai18n.jar:j2ee.jar EmailSampleText.java
* java -classpath .:orai18n.jar:j2ee.jar EmailSampleText
*/
public class EmailSampleText
{
public static void main(String[] args)
{
send("localhost", // smtp host name
"your.address@your-company.com", // from email address
"You", // from display email
"somebody@some-company.com", // to email address
"Subject test zh CN", // subject
"Content •4E02 from Text email", // body
new Locale("zh", "CN") // user locale
);
}
public static void send(String smtp, String fromEmail, String fromDispName,
String toEmail, String subject, String content, Locale locale
)
{
// get the list of common email character sets
final String[] charset = LocaleMapper.getIANACharSetFromLocale(LocaleMapper.
EMAIL_WINDOWS,
locale
);
// pick the first one for the email encoding
final String contentType = "text/plain; charset=" + charset[0];
try
{
Properties props = System.getProperties();
props.put("mail.smtp.host", smtp);
// here, set username / password if necessary
Session session = Session.getDefaultInstance(props, null);
MimeMessage mimeMessage = new MimeMessage(session);
mimeMessage.setFrom(new InternetAddress(fromEmail, fromDispName,
The GDK Application Configuration File
Oracle Globalization Development Kit 8-35
charset[0]
)
);
mimeMessage.setRecipients(Message.RecipientType.TO, toEmail);
mimeMessage.setSubject(MimeUtility.encodeText(subject, charset[0], "Q"));
// body
mimeMessage.setContent(content, contentType);
mimeMessage.setHeader("Content-Type", contentType);
mimeMessage.setHeader("Content-Transfer-Encoding", "8bit");
mimeMessage.setSentDate(new Date());
Transport.send(mimeMessage);
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
The GDK Application Configuration File
The GDK application configuration file dictates the behavior and the properties of the
GDK application framework and the application that is using it. It contains locale
mapping tables and parameters for the configuration of the application. One
configuration file is required for each application.
The gdkapp.xml application configuration file is an XML document. This file resides
in the ./WEB-INF directory of the J2EE environment of the application.
The following sections describe the contents and the properties of the application
configuration file in detail:
■locale-charset-maps
■page-charset
■application-locales
■locale-determine-rule
■locale-parameter-name
■message-bundles
■url-rewrite-rule
■Example: GDK Application Configuration File
locale-charset-maps
This section enables applications to override the mapping from the language to the
default character set provided by the GDK. This mapping is used when the
page-charset is set to AUTO-CHARSET.
For example, for the en locale, the default GDK character set is windows-1252.
However, if the application requires ISO-8859-1, this can be specified as follows:
<locale-charset-maps>
<locale-charset>
<locale>en</locale>
<charset>ISO_8859-1</charset>
</locale-charset>
</locale-charset-maps>
The GDK Application Configuration File
8-36 Oracle Database Globalization Support Guide
The locale name is comprised of the language code and the country code, and they
should follow the ISO naming convention as defined in ISO 639 and ISO 3166,
respectively. The character set name follows the IANA convention.
Optionally, the user-agent parameter can be specified in the mapping table to
distinguish different clients as follows:
<locale-charset>
<locale>en,de</locale>
<user-agent>^Mozilla
⁄
4.0</user-agent>
<charset>ISO-8859-1</charset>
</locale-charset>
The previous example shows that if the user-agent value in the HTTP header starts
with Mozilla/4.0 (which indicates an older version of Web clients) for English (en)
and German (de) locales, then the GDK sets the character set to ISO-8859-1.
Multiple locales can be specified in a comma-delimited list.
page-charset
This tag section defines the character set of the application pages. If this is explicitly set
to a given character set, then all pages use this character set. The character set name
must follow the IANA character set convention, for example:
<page-charset>UTF-8</page-charset>
However, if the page-charset is set to AUTO-CHARSET, then the character set is
based on the default character set of the current user locale. The default character set is
derived from the locale to character set mapping table specified in the application
configuration file.
If the character set mapping table in the application configuration file is not available,
then the character set is based on the default locale name to IANA character set
mapping table in the GDK. Default mappings are derived from OraLocaleInfo
class.
application-locales
This tag section defines a list of the locales supported by the application. For example:
<application-locales>
<locale default="yes">en-US</locale>
<locale>de</locale>
<locale>zh-CN</locale>
</application-locales>
If the language component is specified with the * country code, then all locale names
with this language code qualify. For example, if de-* (the language code for German)
is defined as one of the application locales, then this supports de-AT (German-
Austria), de (German-Germany), de-LU (German-Luxembourg), de-CH
See Also: "page-charset" on page 8-36
See Also:
■"locale-charset-maps" on page 8-35
■"Handling Non-ASCII Input and Output in the GDK
Framework" on page 8-23
The GDK Application Configuration File
Oracle Globalization Development Kit 8-37
(German-Switzerland), and even irregular locale combination such as de-CN
(German-China). However, the application can be restricted to support a predefined
set of locales.
It is recommended to set one of the application locales as the default application locale
(by specifying default="yes") so that it can be used as a fall back locale for
customers who are connecting to the application with an unsupported locale.
locale-determine-rule
This section defines the order in which the preferred user locale is determined. The
locale sources should be specified based on the scenario in the application. This section
includes the following scenarios:
■Scenario 1: The GDK framework uses the accept language at all times.
<locale-source>oracle.i18n.servlet.localesource.HTTPAcceptLanguage</locale-source>
■Scenario 2: By default, the GDK framework uses the accept language. After the
user specifies the locale, the locale is used for further operations.
<locale-source>oracle.i18n.servlet.localesource.UserInput</locale-source>
<locale-source>oracle.i18n.servlet.localesource.HTTPAcceptLanguage</locale-source>
■Scenario 3: By default, the GDK framework uses the accept language. After the
user is authenticated, the GDK framework uses the database locale source. The
database locale source is cached until the user logs out. After the user logs out, the
accept language is used again.
<db-locale-source
data-source-name="jdbc/OracleCoreDS"
locale-source-table="customer"
user-column="customer_email"
user-key="userid"
language-column="nls_language"
territory-column="nls_territory"
timezone-column="timezone"
>oracle.i18n.servlet.localesource.DBLocaleSource</db-locale-source>
<locale-source>oracle.i18n.servlet.localesource.HttpAcceptLanguage</locale-source>
Note that Scenario 3 includes the predefined database locale source,
DBLocaleSource. It enables the user profile information to be specified in the
configuration file without writing a custom database locale source. In the example, the
user profile table is called "customer". The columns are "customer_email",
"nls_language", "nls_territory", and "timezone". They store the unique
e-mail address, the Oracle name of the preferred language, the Oracle name of the
preferred territory, and the time zone ID of a customer. The user-key is a mandatory
attribute that specifies the attribute name used to pass the user ID from the application
to the GDK framework.
■Scenario 4: The GDK framework uses the accept language in the first page. When
the user inputs a locale, it is cached and used until the user logs into the
application. After the user is authenticated, the GDK framework uses the database
locale source. The database locale source is cached until the user logs out. After the
user logs out, the accept language is used again or the user input is used if the user
inputs a locale.
<locale-source>demo.DatabaseLocaleSource</locale-source>
<locale-source>oracle.i18n.servlet.localesource.UserInput</locale-source>
<locale-source>oracle.i18n.servlet.localesource.HttpAcceptLanguage</locale-source>
The GDK Application Configuration File
8-38 Oracle Database Globalization Support Guide
Note that Scenario 4 uses the custom database locale source. If the user profile schema
is complex, such as user profile information separated into multiple tables, then the
custom locale source should be provided by the application. Examples of custom
locale sources can be found in the $ORACLE_HOME/nls/gdk/demo directory.
locale-parameter-name
This tag defines the name of the locale parameters that are used in the user input so
that the current user locale can be passed between requests.
Table 8–3 shows the parameters used in the GDK framework.
The parameter names are used in either the parameter in the HTML form or in the
URL.
message-bundles
This tag defines the base class names of the resource bundles used in the application.
The mapping is used in the Localizer.getMessage method for locating translated
text in the resource bundles.
<message-bundles>
<resource-bundle>Messages</resource-bundle>
<resource-bundle name="newresource">NewMessages</resource-bundle>
</message-bundles>
Table 8–3 Locale Parameters Used in the GDK Framework
Default Parameter Name Value
locale ISO locale where ISO 639 language code and ISO 3166 country code are connected
with an underscore (_).or a hyphen (-). For example, zh_CN for Simplified Chinese
used in China
language Oracle language name. For example, AMERICAN for American English
territory Oracle territory name. For example, SPAIN
timezone Timezone name. For example, American/Los_Angeles
iso-currency ISO 4217 currency code. For example, EUR for the euro
date-format Date format pattern mask. For example, DD_MON_RRRR
long-date-format Long date format pattern mask. For example, DAY-YYY-MM-DD
date-time-format Date and time format pattern mask. For example, DD-MON-RRRR HH24:MI:SS
long-date-time-format Long date and time format pattern mask. For example, DAY YYYY-MM-DD
HH12:MI:SS AM
time-format Time format pattern mask. For example, HH:MI:SS
number-format Number format. For example, 9G99G990D00
currency-format Currency format. For example, L9G99G990D00
linguistic-sorting Linguistic sort order name. For example, JAPANESE_M for Japanese multilingual
sort
charset Character set. For example, WE8ISO8859P15
writing-direction Writing direction string. For example, LTR for left-to-right writing direction or RTL
for right-to-left writing direction
command GDK command. For example, store for the update operation
The GDK Application Configuration File
Oracle Globalization Development Kit 8-39
If the name attribute is not specified or if it is specified as name="default" to the
<resource-bundle> tag, then the corresponding resource bundle is used as the
default message bundle. To support more than one resource bundle in an application,
resource bundle names must be assigned to the nondefault resource bundles. The
nondefault bundle names must be passed as a parameter of the getMessage method.
For example:
Localizer loc = ServletHelper.getLocalizerInstance(request);
String translatedMessage = loc.getMessage("Hello");
String translatedMessage2 = loc.getMessage("World", "newresource");
url-rewrite-rule
This tag is used to control the behavior of the URL rewrite operations. The rewriting
rule is a regular expression.
<url-rewrite-rule fallback="no">
<pattern>(.*)/([^/]+)$</pattern>
<result>$1/$L/$2</result>
</url-rewrite-rule>
If the localized content for the requested locale is not available, then it is possible for
the GDK framework to trigger the locale fallback mechanism by mapping it to the
closest translation locale. By default the fallback option is turned off. This can be
turned on by specifying fallback="yes".
For example, suppose an application supports only the following translations: en, de,
and ja, and en is the default locale of the application. If the current application locale
is de-US, then it falls back to de. If the user selects zh-TW as its application locale,
then it falls back to en.
A fallback mechanism is often necessary if the number of supported application
locales is greater than the number of the translation locales. This usually happens if
multiple locales share one translation. One example is Spanish. The application may
need to support multiple Spanish-speaking countries and not just Spain, with one set
of translation files.
Multiple URL rewrite rules can be specified by assigning the name attribute to
nondefault URL rewrite rules. To use the nondefault URL rewrite rules, the name must
be passed as a parameter of the rewrite URL method. For example:
<img src="<%=ServletHelper.rewriteURL("images/welcome.gif", request) %>">
<img src="<%=ServletHelper.rewriteURL("US.gif", "flag", request) %>">
The first rule changes the "images/welcome.gif" URL to the localized welcome
image file. The second rule named "flag" changes the "US.gif" URL to the user's
country flag image file. The rule definition should be as follows:
<url-rewrite-rule fallback="yes">
<pattern>(.*)/([^/]+)$</pattern>
<result>$1/$L/$2</result>
</url-rewrite-rule>
<url-rewrite-rule name="flag">
<pattern>US.gif/pattern>
<result>$C.gif</result>
</url-rewrite-rule>
See Also: "Managing Localized Content in the GDK" on page 8-25
The GDK Application Configuration File
8-40 Oracle Database Globalization Support Guide
Example: GDK Application Configuration File
This section contains an example of an application configuration file with the
following application properties:
■The application supports the following locales: Arabic (ar), Greek (el), English
(en), German (de), French (fr), Japanese (ja) and Simplified Chinese for China
(zh-CN).
■English is the default application locale.
■The page character set for the ja locale is always UTF-8.
■The page character set for the en and de locales when using an Internet Explorer
client is windows-1252.
■The page character set for the en, de, and fr locales on other web browser clients
is iso-8859-1.
■The page character sets for all other locales are the default character set for the
locale.
■The user locale is determined by the following order: user input locale and then
Accept-Language.
■The localized contents are stored in their appropriate language subfolders. The
folder names are derived from the ISO 639 language code. The folders are located
in the root directory of the application. For example, the Japanese file for
/shop/welcome.jpg is stored in /ja/shop/welcome.jpg.
<?xml version="1.0" encoding="utf-8"?>
<gdkapp
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="gdkapp.xsd">
<!-- Language to Character set mapping -->
<locale-charset-maps>
<locale-charset>
<locale>ja</locale>
<charset>UTF-8</charset>
</locale-charset>
<locale-charset>
<locale>en,de</locale>
<user-agent>^Mozilla\/[0-9\. ]+\(compatible; MSIE [^;]+; \)</user-agent>
<charset>WINDOWS-1252</charset>
</locale-charset>
<locale-charset>
<locale>en,de,fr</locale>
<charset>ISO-8859-1</charset>
</locale-charset>
</locale-charset-maps>
<!-- Application Configurations -->
<page-charset>AUTO-CHARSET</page-charset>
<application-locales>
<locale>ar</locale>
<locale>de</locale>
<locale>fr</locale>
<locale>ja</locale>
<locale>el</locale>
<locale default="yes">en</locale>
<locale>zh-CN</locale>
</application-locales>
<locale-determine-rule>
<locale-source>oracle.i18n.servlet.localesource.UserInput</locale-source>
<locale-source>oracle.i18n.servlet.localesource.HttpAcceptLanguage</locale-source>
</locale-determine-rule>
GDK for Java Supplied Packages and Classes
Oracle Globalization Development Kit 8-41
<!-- URL rewriting rule -->
<url-rewrite-rule fallback="no">
<pattern>(.*)/([^/]+)$</pattern>
<result>/$L/$1/$2</result>
</url-rewrite-rule>
</gdkapp>
GDK for Java Supplied Packages and Classes
Oracle Globalization Services for Java contains the following packages:
■oracle.i18n.lcsd
■oracle.i18n.net
■oracle.i18n.servlet
■oracle.i18n.text
■oracle.i18n.util
oracle.i18n.lcsd
Package oracle.i18n.lcsd provides classes to automatically detect and recognize
language and character set based on text input. It supports the detection of both plain
text and HTML files. Language is based on ISO; encoding is based on IANA or Oracle
character sets. It includes the following classes:
■LCSDetector: Contains methods to automatically detect and recognize language
and character set based on text input.
■LCSDResultSet: The LCSDResultSet class is for storing the result generated by
LCSDetector. Methods in this class can be used to retrieve specific information
from the result.
■LCSDetectionInputStream: Transparently detects the language and encoding
for the stream object.
■LCSDetectionReader: Transparently detects the language and encoding and
converts the input data to Unicode.
■LCSDetectionHTMLInputStream: Extends the LCSDetectionInputStream
class to support the language and encoding detection for input in HTML format.
■LCSDetectionHTMLReader: Extends the LCSDetectionReader class to
support the language and encoding detection for input in HTML format.
oracle.i18n.net
Package oracle.i18n.net provides Internet-related data conversions for
globalization. It includes the following classes:
■CharEntityReference: A utility class to escape or unescape a string into
character reference or entity reference form
■CharEntityReference.Form: A form parameter class that specifies the
escaped form
See Also: Oracle Globalization Development Kit Java API Reference
GDK for PL/SQL Supplied Packages
8-42 Oracle Database Globalization Support Guide
oracle.i18n.servlet
Package oracle.i18n.Servlet enables JSP and JavaServlet to have automatic
locale support and also returns the localized contents to the application. It includes the
following classes:
■ApplicationContext: An application context class that governs application
scope operation in the framework
■Localizer: An all-in-one object class that enables access to the most commonly
used globalization information
■ServletHelper: A delegate class that bridges between Java servlets and
globalization objects
oracle.i18n.text
Package oracle.i18n.text provides general text data globalization support. It
includes the following classes:
■OraCollationKey: A class which represents a String under certain rules of a
specific OraCollator object
■OraCollator: A class to perform locale-sensitive string comparison, including
linguistic collation and binary sorting
■OraDateFormat: An abstract class to do formatting and parsing between
datetime and string locale. It supports Oracle datetime formatting behavior.
■OraDecimalFormat: A concrete class to do formatting and parsing between
number and string locale. It supports Oracle number formatting behavior.
■OraDecimalFormatSymbol: A class to maintain Oracle format symbols used by
Oracle number and currency formatting
■OraNumberFormat: An abstract class to do formatting and parsing between
number and string locale. It supports Oracle number formatting behavior.
■OraSimpleDateFormat: A concrete class to do formatting and parsing between
datetime and string locale. It supports Oracle datetime formatting behavior.
oracle.i18n.util
Package oracle.i18n.util provides general utilities for globalization support. It
includes the following classes:
■LocaleMapper: Provides mappings between Oracle locale elements and
equivalent locale elements in other vendors and standards
■OraDisplayLocaleInfo: A translation utility class that provides the
translations of locale and attributes
■OraLocaleInfo: An Oracle locale class that includes the language, territory, and
collator objects
■OraSQLUtil: An Oracle SQL Utility class that includes some useful methods of
dealing with SQL
GDK for PL/SQL Supplied Packages
The GDK for PL/SQL includes the following PL/SQL packages:
■UTL_I18N
GDK Error Messages
Oracle Globalization Development Kit 8-43
■UTL_LMS
UTL_I18N is a set of PL/SQL services that help developers to build globalized
applications. The UTL_I18N PL/SQL package provides the following functions:
■String conversion functions for various datatypes
■Escape and unescape sequences for predefined characters and multibyte
characters used by HTML and XML documents
■Functions that map between Oracle, Internet Assigned Numbers Authority
(IANA), ISO, and e-mail application character sets, languages, and territories
■A function that returns the Oracle character set name from an Oracle language
name
■A function that performs script transliteration
■Functions that return the ISO currency code, local time zones, and local languages
supported for a given territory
■Functions that return the most commonly used linguistic sort, a listing of all
applicable linguistic sorts, and the local territories supported for a given language
■Functions that map between Oracle full and short language names
■A function that returns the language translation of a given language and territory
name
■A function that returns a listing of the most commonly used time zones
UTL_LMS retrieves and formats error messages in different languages.
GDK Error Messages
GDK-03001 Invalid or unsupported sorting rule
Cause: An invalid or unsupported sorting rule name was specified.
Action: Choose a valid sorting rule name and check the Globalization Support
Guide for the list of sorting rule names.
GDK-03002 The functional-driven sort is not supported.
Cause: A functional-driven sorting rule name was specified.
Action: Choose a valid sorting rule name and check the Globalization Support
Guide for the list of sorting rule names.
GDK-03003 The linguistic data file is missing.
Cause: A valid sorting rule was specified, but the associated data file was not
found.
Action: Make sure the GDK jar files are correctly installed in the Java application.
GDK-03005 Binary sort is not available for the specified character set .
Cause: Binary sorting for the specified character set is not supported.
Action: Check the Globalization Support Guide for a character set that supports
binary sort.
GDK-03006 The comparison strength level setting is invalid.
Cause: An invalid comparison strength level was specified.
See Also: PL/SQL Packages and Types Reference
GDK Error Messages
8-44 Oracle Database Globalization Support Guide
Action: Choose a valid comparison strength level from the list -- PRIMARY,
SECONDARY or TERTIARY.
GDK-03007 The composition level setting is invalid.
Cause: An invalid composition level setting was specified.
Action: Choose a valid composition level from the list -- NO_COMPOSITION or
CANONICAL_COMPOSITION.
GDK-04001 Cannot map Oracle character to Unicode
Cause: The program attempted to use a character in the Oracle character set that
cannot be mapped to Unicode.
Action: Write a separate exception handler for the invalid character, or call the
withReplacement method so that the invalid character can be replaced with a valid
replacement character.
GDK-04002 Cannot map Unicode to Oracle character
Cause: The program attempted to use an Unicode character that cannot be
mapped to a character in the Oracle character set.
Action: Write a separate exception handler for the invalid character, or call the
withReplacement method so that the invalid character can be replaced with a valid
replacement character.
GDK-05000 A literal in the date format is too large.
Cause: The specified string literal in the date format was too long.
Action: Use a shorter string literal in the date format.
GDK-05001 The date format is too long for internal buffer.
Cause: The date format pattern was too long.
Action: Use a shorter date format pattern.
GDK-05002 The Julian date is out of range.
Cause: An illegal date range was specified.
Action: Make sure that date is in the specified range 0 - 3439760.
GDK-05003 Failure in retrieving date/time
Cause: This is an internal error.
Action: Contact Oracle Support Services.
GDK-05010 Duplicate format code found
Cause: The same format code was used more than once in the format pattern.
Action: Remove the redundant format code.
GDK-05011 The Julian date precludes the use of the day of the year.
Cause: Both the Julian date and the day of the year were specified.
Action: Remove either the Julian date or the day of the year.
GDK-05012 The year may only be specified once.
Cause: The year format code appeared more than once.
Action: Remove the redundant year format code.
GDK-05013 The hour may only be specified once.
Cause: The hour format code appeared more than once.
GDK Error Messages
Oracle Globalization Development Kit 8-45
Action: Remove the redundant hour format code.
GDK-05014 The AM/PM conflicts with the use of A.M./P.M.
Cause: AM/PM was specified along with A.M./P.M.
Action: Use either AM/PM or A.M./P.M; do not use both.
GDK-05015 The BC/AD conflicts with the use of B.C./A.D.
Cause: BC/AD was specified along with B.C./A.D.
Action: Use either BC/AD or B.C./A.D.; do not use both.
GDK-05016 Duplicate month found
Cause: The month format code appeared more than once.
Action: Remove the redundant month format code.
GDK-05017 The day of the week may only be specified once.
Cause: The day of the week format code appeared more than once.
Action: Remove the redundant day of the week format code.
GDK-05018 The HH24 precludes the use of meridian indicator.
Cause: HH24 was specified along with the meridian indicator.
Action: Use either the HH24 or the HH12 with the meridian indicator.
GDK-05019 The signed year precludes the use of BC/AD.
Cause: The signed year was specified along with BC/AD.
Action: Use either the signed year or the unsigned year with BC/AD.
GDK-05020 A format code cannot appear in a date input format.
Cause: A format code appeared in a date input format.
Action: Remove the format code.
GDK-05021 Date format not recognized
Cause: An unsupported format code was specified.
Action: Correct the format code.
GDK-05022 The era format code is not valid with this calendar.
Cause: An invalid era format code was specified for the calendar.
Action: Remove the era format code or use anther calendar that supports the era.
GDK-05030 The date format pattern ends before converting entire input string.
Cause: An incomplete date format pattern was specified.
Action: Rewrite the format pattern to cover the entire input string.
GDK-05031 The year conflicts with the Julian date.
Cause: An incompatible year was specified for the Julian date.
Action: Make sure that the Julian date and the year are not in conflict.
GDK-05032 The day of the year conflicts with the Julian date.
Cause: An incompatible day of year was specified for the Julian date.
Action: Make sure that the Julian date and the day of the year are not in conflict.
GDK-05033 The month conflicts with the Julian date.
GDK Error Messages
8-46 Oracle Database Globalization Support Guide
Cause: An incompatible month was specified for the Julian date.
Action: Make sure that the Julian date and the month are not in conflict.
GDK-05034 The day of the month conflicts with the Julian date.
Cause: An incompatible day of the month was specified for the Julian date.
Action: Make sure that the Julian date and the day of the month are not in
conflict.
GDK-05035 The day of the week conflicts with the Julian date.
Cause: An incompatible day of the week was specified for the Julian date.
Action: Make sure that the Julian date and the day of week are not in conflict.
GDK-05036 The hour conflicts with the seconds in the day.
Cause: The specified hour and the seconds in the day were not compatible.
Action: Make sure the hour and the seconds in the day are not in conflict.
GDK-05037 The minutes of the hour conflicts with the seconds in the day.
Cause: The specified minutes of the hour and the seconds in the day were not
compatible.
Action: Make sure the minutes of the hour and the seconds in the day are not in
conflict.
GDK-05038 The seconds of the minute conflicts with the seconds in the day.
Cause: The specified seconds of the minute and the seconds in the day were not
compatible.
Action: Make sure the seconds of the minute and the seconds in the day are not in
conflict.
GDK-05039 Date not valid for the month specified
Cause: An illegal date for the month was specified.
Action: Check the date range for the month.
GDK-05040 Input value not long enough for the date format
Cause: Too many format codes were specified.
Action: Remove unused format codes or specify a longer value.
GDK-05041 A full year must be between -4713 and +9999, and not be 0.
Cause: An illegal year was specified.
Action: Specify the year in the specified range.
GDK-05042 A quarter must be between 1 and 4.
Cause: Cause: An illegal quarter was specified.
Action: Action: Make sure that the quarter is in the specified range.
GDK-05043 Not a valid month
Cause: An illegal month was specified.
Action: Make sure that the month is between 1 and 12 or has a valid month name.
GDK-05044 The week of the year must be between 1 and 52.
Cause: An illegal week of the year was specified.
Action: Make sure that the week of the year is in the specified range.
GDK Error Messages
Oracle Globalization Development Kit 8-47
GDK-05045 The week of the month must be between 1 and 5.
Cause: An illegal week of the month was specified.
Action: Make sure that the week of the month is in the specified range.
GDK-05046 Not a valid day of the week
Cause: An illegal day of the week was specified.
Action: Make sure that the day of the week is between 1 and 7 or has a valid day
name.
GDK-05047 A day of the month must be between 1 and the last day of the month.
Cause: An illegal day of the month was specified.
Action: Make sure that the day of the month is in the specified range.
GDK-05048 A day of year must be between 1 and 365 (366 for leap year).
Cause: An illegal day of the year was specified.
Action: Make sure that the day of the year is in the specified range.
GDK-05049 An hour must be between 1 and 12.
Cause: An illegal hour was specified.
Action: Make sure that the hour is in the specified range.
GDK-05050 An hour must be between 0 and 23.
Cause: An illegal hour was specified.
Action: Make sure that the hour is in the specified range.
GDK-05051 A minute must be between 0 and 59.
Cause: Cause: An illegal minute was specified.
Action: Action: Make sure the minute is in the specified range.
GDK-05052 A second must be between 0 and 59.
Cause: An illegal second was specified.
Action: Make sure the second is in the specified range.
GDK-05053 A second in the day must be between 0 and 86399.
Cause: An illegal second in the day was specified.
Action: Make sure second in the day is in the specified range.
GDK-05054 The Julian date must be between 1 and 5373484.
Cause: An illegal Julian date was specified.
Action: Make sure that the Julian date is in the specified range.
GDK-05055 Missing AM/A.M. or PM/P.M.
Cause: Neither AM/A.M. nor PM/P.M. was specified in the format pattern.
Action: Specify either AM/A.M. or PM/P.M.
GDK-05056 Missing BC/B.C. or AD/A.D.
Cause: Neither BC/B.C. nor AD/A.D. was specified in the format pattern.
Action: Specify either BC/B.C. or AD/A.D.
GDK-05057 Not a valid time zone
Cause: An illegal time zone was specified.
GDK Error Messages
8-48 Oracle Database Globalization Support Guide
Action: Specify a valid time zone.
GDK-05058 Non-numeric character found
Cause: A non-numeric character was found where a numeric character was
expected.
Action: Make sure that the character is a numeric character.
GDK-05059 Non-alphabetic character found
Cause: A non-alphabetic character was found where an alphabetic was expected.
Action: Make sure that the character is an alphabetic character.
GDK-05060 The week of the year must be between 1 and 53.
Cause: An illegal week of the year was specified.
Action: Make sure that the week of the year is in the specified range.
GDK-05061 The literal does not match the format string.
Cause: The string literals in the input were not the same length as the literals in
the format pattern (with the exception of the leading whitespace).
Action: Correct the format pattern to match the literal. If the "FX" modifier has
been toggled on, the literal must match exactly, with no extra whitespace.
GDK-05062 The numeric value does not match the length of the format item.
Cause: The numeric value did not match the length of the format item.
Action: Correct the input date or turn off the FX or FM format modifier. When the
FX and FM format codes are specified for an input date, then the number of digits
must be exactly the number specified by the format code. For example, 9 will not
match the format code DD but 09 will.
GDK-05063 The year is not supported for the current calendar.
Cause: An unsupported year for the current calendar was specified.
Action: Check the Globalization Support Guide to find out what years are
supported for the current calendar.
GDK-05064 The date is out of range for the calendar.
Cause: The specified date was out of range for the calendar.
Action: Specify a date that is legal for the calendar.
GDK-05065 Invalid era
Cause: An illegal era was specified.
Action: Make sure that the era is valid.
GDK-05066 The datetime class is invalid.
Cause: This is an internal error.
Action: Contact Oracle Support Services.
GDK-05067 The interval is invalid.
Cause: An invalid interval was specified.
Action: Specify a valid interval.
GDK-05068 The leading precision of the interval is too small.
Cause: The specified leading precision of the interval was too small to store the
interval.
GDK Error Messages
Oracle Globalization Development Kit 8-49
Action: Increase the leading precision of the interval or specify an interval with a
smaller leading precision.
GDK-05069 Reserved for future use
Cause: Reserved.
Action: Reserved.
GDK-05070 The specified intervals and datetimes were not mutually comparable.
Cause: The specified intervals and datetimes were not mutually comparable.
Action: Specify a pair of intervals or datetimes that are mutually comparable.
GDK-05071 The number of seconds must be less than 60.
Cause: The specified number of seconds was greater than 59.
Action: Specify a value for the seconds to 59 or smaller.
GDK-05072 Reserved for future use
Cause: Reserved.
Action: Reserved.
GDK-05073 The leading precision of the interval was too small.
Cause: The specified leading precision of the interval was too small to store the
interval.
Action: Increase the leading precision of the interval or specify an interval with a
smaller leading precision.
GDK-05074 An invalid time zone hour was specified.
Cause: The hour in the time zone must be between -12 and 13.
Action: Specify a time zone hour between -12 and 13.
GDK-05075 An invalid time zone minute was specified.
Cause: The minute in the time zone must be between 0 and 59.
Action: Specify a time zone minute between 0 and 59.
GDK-05076 An invalid year was specified.
Cause: A year must be at least -4713.
Action: Specify a year that is greater than or equal to -4713.
GDK-05077 The string is too long for the internal buffer.
Cause: This is an internal error.
Action: Contact Oracle Support Services.
GDK-05078 The specified field was not found in the datetime or interval.
Cause: The specified field was not found in the datetime or interval.
Action: Make sure that the specified field is in the datetime or interval.
GDK-05079 An invalid hh25 field was specified.
Cause: The hh25 field must be between 0 and 24.
Action: Specify an hh25 field between 0 and 24.
GDK-05080 An invalid fractional second was specified.
Cause: The fractional second must be between 0 and 999999999.
GDK Error Messages
8-50 Oracle Database Globalization Support Guide
Action: Specify a value for fractional second between 0 and 999999999.
GDK-05081 An invalid time zone region ID was specified.
Cause: The time zone region ID specified was invalid.
Action: Contact Oracle Support Services.
GDK-05082 Time zone region name not found
Cause: The specified region name cannot be found.
Action: Contact Oracle Support Services.
GDK-05083 Reserved for future use
Cause: Reserved.
Action: Reserved.
GDK-05084 Internal formatting error
Cause: This is an internal error.
Action: Contact Oracle Support Services.
GDK-05085 Invalid object type
Cause: An illegal object type was specified.
Action: Use a supported object type.
GDK-05086 Invalid date format style
Cause: An illegal format style was specified.
Action: Choose a valid format style.
GDK-05087 A null format pattern was specified.
Cause: The format pattern cannot be null.
Action: Provide a valid format pattern.
GDK-05088 Invalid number format model
Cause: An illegal number format code was specified.
Action: Correct the number format code.
GDK-05089 Invalid number
Cause: An invalid number was specified.
Action: Correct the input.
GDK-05090 Reserved for future use
Cause: Reserved.
Action: Reserved.
GDK-0509 Datetime/interval internal error
Cause: This is an internal error.
Action: Contact Oracle Support Services.
GDK-05098 Too many precision specifiers
Cause: Extra data was found in the date format pattern while the program
attempted to truncate or round dates.
Action: Check the syntax of the date format pattern.
GDK Error Messages
Oracle Globalization Development Kit 8-51
GDK-05099 Bad precision specifier
Cause: An illegal precision specifier was specified.
Action: Use a valid precision specifier.
GDK-05200 Missing WE8ISO8859P1 data file
Cause: The character set data file for WE8ISO8859P1 was not installed.
Action: Make sure the GDK jar files are installed properly in the Java application.
GDK-05201 Failed to convert to a hexadecimal value
Cause: An invalid hexadecimal string was included in the HTML/XML data.
Action: Make sure the string includes the hexadecimal character in the form of
&x[0-9A-Fa-f]+;.
GDK-05202 Failed to convert to a decimal value
Cause: An invalid decimal string was found in the HTML/XML data.
Action: Make sure the string includes the decimal character in the form of
&[0-9]+;.
GDK-05203 Unregistered character entity
Cause: An invalid character entity was found in the HTML/XML data.
Action: Use a valid character entity value in HTML/XML data. See HTML/XML
standards for the registered character entities.
GDK-05204 Invalid Quoted-Printable value
Cause: An invalid Quoted-Printable data was found in the data.
Action: Make sure the input data has been encoded in the proper
Quoted-Printable form.
GDK-05205 Invalid MIME header format
Cause: An invalid MIME header format was specified.
Action: Check RFC 2047 for the MIME header format. Make sure the input data
conforms to the format.
GDK-05206 Invalid numeric string
Cause: An invalid character in the form of %FF was found when a URL was being
decoded.
Action: Make sure the input URL string is valid and has been encoded correctly;
%FF needs to be a valid hex number.
GDK-05207 Invalid class of the object, key, in the user-defined locale to charset
mapping"
Cause: The class of key object in the user-defined locale to character set mapping
table was not java.util.Locale.
Action: When you construct the Map object for the user-defined locale to
character set mapping table, specify java.util.Locale for the key object.
GDK-05208 Invalid class of the object, value, in the user-defined locale to charset
mapping
Cause: The class of value object in the user-defined locale to character set
mapping table was not java.lang.String.
Action: When you construct the Map object for the user-defined locale to
character set mapping table, specify java.lang.String for the value object.
GDK Error Messages
8-52 Oracle Database Globalization Support Guide
GDK-05209 Invalid rewrite rule
Cause: An invalid regular expression was specified for the match pattern in the
rewrite rule.
Action: Make sure the match pattern for the rewriting rule uses a valid regular
expression.
GDK-05210 Invalid character set
Cause: An invalid character set name was specified.
Action: Specify a valid character set name.
GDK-0521 Default locale not defined as a supported locale
Cause: The default application locale was not included in the supported locale
list.
Action: Include the default application locale in the supported locale list or
change the default locale to the one that is in the list of the supported locales.
GDK-05212 The rewriting rule must be a String array with three elements.
Cause: The rewriting rule parameter was not a String array with three elements.
Action: Make sure the rewriting rule parameter is a String array with three
elements. The first element represents the match pattern in the regular expression,
the second element represents the result pattern in the form specified in the
JavaDoc of ServletHelper.rewriteURL, and the third element represents the
Boolean value "True" or "False" that specifies whether the locale fallback operation
is performed or not.
GDK-05213 Invalid type for the class of the object, key, in the user-defined
parameter name mapping
Cause: The class of key object in the user-defined parameter name mapping table
was not java.lang.String.
Action: When you construct the Map object for the user-defined parameter name
mapping table, specify java.lang.String for the key object.
GDK-05214 The class of the object, value, in the user-defined parameter name
mapping, must be of type \"java.lang.String\".
Cause: The class of value object in the user-defined parameter name mapping
table was not java.lang.String.
Action: When you construct the Map object for the user-defined parameter name
mapping table, specify java.lang.String for the value object.
GDK-05215 Parameter name must be in the form [a-z][a-z0-9]*.
Cause: An invalid character was included in the parameter name.
Action: Make sure the parameter name is in the form of [a-z][a-z0-9]*.
GDK-05216 The attribute \"var\" must be specified if the attribute \"scope\" is set.
Cause: Despite the attribute "scope" being set in the tag, the attribute "var" was
not specified.
Action: Specify the attribute "var" for the name of variable.
GDK-05217 The \"param\" tag must be nested inside a \"message\" tag.
Cause: The "param" tag was not nested inside a "message" tag.
Action: Make sure the tag "param" is inside the tag "message".
GDK Error Messages
Oracle Globalization Development Kit 8-53
GDK-05218 Invalid \"scope\" attribute is specified.
Cause: An invalid "scope" value was specified.
Action: Specify a valid scope as either "application," "session," "request," or
"page".
GDK-05219 Invalid date format style
Cause: The specified date format style was invalid.
Action: Specify a valid date format style as either "default," "short," or "long"
GDK-05220 No corresponding Oracle character set exists for the IANA character set.
Cause: An unsupported IANA character set name was specified.
Action: Specify the IANA character set that has a corresponding Oracle character
set.
GDK-05221 Invalid parameter name
Cause: An invalid parameter name was specified in the user-defined parameter
mapping table.
Action: Make sure the specified parameter name is supported. To get the list of
supported parameter names, call LocaleSource.Parameter.toArray.
GDK-05222 Invalid type for the class of the object, key, in the user-defined message
bundle mapping.
Cause: The class of key object in the user-defined message bundle mapping table
was not "java.lang.String."
Action: When you construct the Map object for the user-defined message bundle
mapping table, specify java.lang.String for the key object.
GDK-05223 Invalid type for the class of the object, value, in the user-defined
message bundle mapping
Cause: The class of value object in the user-defined message bundle mapping
table was not "java.lang.String."
Action: When you construct the Map object for the user-defined message bundle
mapping table, specify java.lang.String for the value object.
GDK-05224 Invalid locale string
Cause: An invalid character was included in the specified ISO locale names in the
GDK application configuration file.
Action: Make sure the ISO locale names include only valid characters. A typical
name format is an ISO 639 language followed by an ISO 3166 country connected
by a dash character; for example, "en-US" is used to specify the locale for
American English in the United States.
GDK-06001 LCSDetector profile not available
Cause: The specified profile was not found.
Action: Make sure the GDK jar files are installed properly in the Java application.
GDK-06002 Invalid IANA character set name or no corresponding Oracle name
found
Cause: The IANA character set specified was either invalid or did not have a
corresponding Oracle character set.
Action: Check that the IANA character is valid and make sure that it has a
corresponding Oracle character set.
GDK Error Messages
8-54 Oracle Database Globalization Support Guide
GDK-06003 Invalid ISO language name or no corresponding Oracle name found
Cause: The ISO language specified was either invalid or did not have a
corresponding Oracle language.
Action: Check to see that the ISO language specified is valid and has a
corresponding Oracle language.
GDK-06004 A character set filter and a language filter cannot be set at the same
time.
Cause: A character set filter and a language filter were set at the same time in a
LCSDetector object.
Action: Set only one of the two -- character set or language.
GDK-06005 Reset is necessary before LCSDetector can work with a different data
source.
Cause: The reset method was not invoked before a different type of data source
was used for a LCSDetector object.
Action: Call LCSDetector.reset to reset the detector before switching to detect
other types of data source.
ORA-17154 Cannot map Oracle character to Unicode
Cause: The Oracle character was either invalid or incomplete and could not be
mapped to an Unicode value.
Action: Write a separate exception handler for the invalid character, or call the
withReplacement method so that the invalid character can be replaced with a valid
replacement character.
ORA-17155 Cannot map Unicode to Oracle character
Cause: The Unicode character did not have a counterpart in the Oracle character
set.
Action: Write a separate exception handler for the invalid character, or call the
withReplacement method so that the invalid character can be replaced with a valid
replacement character.
SQL and PL/SQL Programming in a Global Environment 9-1
9
SQL and PL/SQL Programming in a Global
Environment
This chapter contains information useful for SQL programming in a globalization
support environment. This chapter includes the following topics:
■Locale-Dependent SQL Functions with Optional NLS Parameters
■Other Locale-Dependent SQL Functions
■Miscellaneous Topics for SQL and PL/SQL Programming in a Global Environment
Locale-Dependent SQL Functions with Optional NLS Parameters
All SQL functions whose behavior depends on globalization support conventions
enable NLS parameters to be specified. These functions are:
TO_CHAR
TO_DATE
TO_NUMBER
NLS_UPPER
NLS_LOWER
NLS_INITCAP
NLSSORT
Explicitly specifying the optional NLS parameters for these functions enables the
functions to be evaluated independently of the session's NLS parameters. This feature
can be important for SQL statements that contain numbers and dates as string literals.
For example, the following query is evaluated correctly if the language specified for
dates is AMERICAN:
SELECT last_name FROM employees WHERE hire_date > '01-JAN-1999';
Such a query can be made independent of the current date language by using a
statement similar to the following:
SELECT last_name FROM employees
WHERE hire_date > TO_DATE('01-JAN-1999','DD-MON-YYYY',
'NLS_DATE_LANGUAGE = AMERICAN');
In this way, SQL statements that are independent of the session language can be
defined where necessary. Such statements are necessary when string literals appear in
SQL statements in views, CHECK constraints, or triggers.
Locale-Dependent SQL Functions with Optional NLS Parameters
9-2 Oracle Database Globalization Support Guide
All character functions support both single-byte and multibyte characters. Except
where explicitly stated, character functions operate character by character, rather than
byte by byte.
The rest of this section includes the following topics:
■Default Values for NLS Parameters in SQL Functions
■Specifying NLS Parameters in SQL Functions
■Unacceptable NLS Parameters in SQL Functions
Default Values for NLS Parameters in SQL Functions
When SQL functions evaluate views and triggers, default values from the current
session are used for the NLS function parameters. When SQL functions evaluate
CHECK constraints, they use the default values that were specified for the NLS
parameters when the database was created.
Specifying NLS Parameters in SQL Functions
NLS parameters are specified in SQL functions as follows:
'parameter = value'
For example:
'NLS_DATE_LANGUAGE = AMERICAN'
The following NLS parameters can be specified in SQL functions:
NLS_DATE_LANGUAGE
NLS_NUMERIC_CHARACTERS
NLS_CURRENCY
NLS_ISO_CURRENCY
NLS_DUAL_CURRENCY
NLS_CALENDAR
NLS_SORT
Table 9–1 shows which NLS parameters are valid for specific SQL functions.
Note: Only SQL statements that must be independent of the
session NLS parameter values should explicitly specify optional
NLS parameters in locale-dependent SQL functions. Using session
default values for NLS parameters in SQL functions usually results
in better performance.
Table 9–1 SQL Functions and Their Valid NLS Parameters
SQL Function Valid NLS Parameters
TO_DATE NLS_DATE_LANGUAGE
NLS_CALENDAR
TO_NUMBER NLS_NUMERIC_CHARACTERS
NLS_CURRENCY
NLS_DUAL_CURRENCY
NLS_ISO_CURRENCY
Locale-Dependent SQL Functions with Optional NLS Parameters
SQL and PL/SQL Programming in a Global Environment 9-3
The following examples show how to use NLS parameters in SQL functions:
TO_DATE ('1-JAN-99', 'DD-MON-YY',
'nls_date_language = American')
TO_CHAR (hire_date, 'DD/MON/YYYY',
'nls_date_language = French')
TO_CHAR (SYSDATE, 'DD/MON/YYYY',
'nls_date_language=''Traditional Chinese'' ')
TO_NUMBER ('13.000,00', '99G999D99',
'nls_numeric_characters = '',.''')
TO_CHAR (salary, '9G999D99L', 'nls_numeric_characters = '',.''
nls_currency = ''EUR''')
TO_CHAR (salary, '9G999D99C', 'nls_numeric_characters = ''.,''
nls_iso_currency = Japan')
NLS_UPPER (last_name, 'nls_sort = Swiss')
NLSSORT (last_name, 'nls_sort = German')
Unacceptable NLS Parameters in SQL Functions
The following NLS parameters are not accepted in SQL functions except for NLSSORT:
TO_CHAR NLS_DATE_LANGUAGE
NLS_NUMERIC_CHARACTERS
NLS_CURRENCY
NLS_ISO_CURRENCY
NLS_DUAL_CURRENCY
NLS_CALENDAR
TO_NCHAR NLS_DATE_LANGUAGE
NLS_NUMERIC_CHARACTERS
NLS_CURRENCY
NLS_ISO_CURRENCY
NLS_DUAL_CURRENCY
NLS_CALENDAR
NLS_UPPER NLS_SORT
NLS_LOWER NLS_SORT
NLS_INITCAP NLS_SORT
NLSSORT NLS_SORT
Note: In some languages, some lowercase characters correspond
to more than one uppercase character or vice versa. As a result, the
length of the output from the NLS_UPPER, NLS_LOWER, and NLS_
INITCAP functions can differ from the length of the input.
See Also: "Special Uppercase Letters" on page 5-8 and "Special
Lowercase Letters" on page 5-8
Table 9–1 (Cont.) SQL Functions and Their Valid NLS Parameters
SQL Function Valid NLS Parameters
Other Locale-Dependent SQL Functions
9-4 Oracle Database Globalization Support Guide
■NLS_LANGUAGE
■NLS_TERRITORY
■NLS_DATE_FORMAT
NLS_DATE_FORMAT and NLS_TERRITORY_FORMAT are not accepted as parameters
because they can interfere with required format masks. A date format must always be
specified if an NLS parameter is in a TO_CHAR or TO_DATE function. As a result, NLS_
DATE_FORMAT and NLS_TERRITORY_FORMAT are not valid NLS parameters for the
TO_CHAR or TO_DATE functions. If you specify NLS_DATE_FORMAT or NLS_
TERRITORY_FORMAT in the TO_CHAR or TO_DATE function, then an error is returned.
NLS_LANGUAGE can interfere with the session value of NLS_DATE_LANGUAGE. If you
specify NLS_LANGUAGE in the TO_CHAR function, for example, then its value is
ignored if it differs from the session value of NLS_DATE_LANGUAGE.
Other Locale-Dependent SQL Functions
This section includes the following topics:
■The CONVERT Function
■SQL Functions for Different Length Semantics
■LIKE Conditions for Different Length Semantics
■Character Set SQL Functions
■The NLSSORT Function
The CONVERT Function
The CONVERT function enables conversion of character data between character sets.
The CONVERT function converts the binary representation of a character string in one
character set to another. It uses exactly the same technique as conversion between
database and client character sets. Hence, it uses replacement characters and has the
same limitations.
The syntax for CONVERT is as follows:
CONVERT(char, dest_char_set[, source_char_set])
char is the value to be converted. source_char_set is the source character set and
dest_char_set is the destination character set. If the source_char_set parameter
is not specified, then it defaults to the database character set.
See Also: "Character Set Conversion Between Clients and the
Server" on page 2-12
See Also:
■Oracle Database SQL Reference for more information about the
CONVERT function
■"Character Set Conversion Support" on page A-16 for character
set encodings that are used only for the CONVERT function
Other Locale-Dependent SQL Functions
SQL and PL/SQL Programming in a Global Environment 9-5
SQL Functions for Different Length Semantics
Oracle provides SQL functions that work in accordance with different length
semantics. There are three groups of such SQL functions: SUBSTR, LENGTH, and
INSTR. Each function in a group is based on a different kind of length semantics and is
distinguished by the character or number appended to the function name. For
example, SUBSTRB is based on byte semantics.
The SUBSTR functions return a requested portion of a substring. The LENGTH
functions return the length of a string. The INSTR functions search for a substring in a
string.
The SUBSTR functions calculate the length of a string differently. Table 9–2
summarizes the calculation methods.
The LENGTH and INSTR functions calculate string length in the same way, according to
the character or number added to the function name.
The following examples demonstrate the differences between SUBSTR and SUBSTRB
on a database whose character set is AL32UTF8.
For the string Fußball, the following statement returns a substring that is 4
characters long, beginning with the second character:
SELECT SUBSTR ('Fußball', 2 , 4) SUBSTR FROM DUAL;
SUBS
----
ußba
For the string Fußball, the following statement returns a substring 4 bytes long,
beginning with the second byte:
SELECT SUBSTRB ('Fußball', 2 , 4) SUBSTRB FROM DUAL;
SUB
---
ußb
Table 9–2 How the SUBSTR Functions Calculate the Length of a String
Function Calculation Method
SUBSTR Calculates the length of a string in characters based on the length semantics associated with the
character set of the datatype. For example, AL32UTF8 characters are calculated in UCS-4
characters. UTF8 and AL16UTF16 characters are calculated in UCS-2 characters. A supplementary
character is counted as one character in AL32UTF8 and as two characters in UTF8 and
AL16UTF16. Because VARCHAR and NVARCHAR may use different character sets, SUBSTR may
give different results for different datatypes even if two strings are identical. If your application
requires consistency, then use SUBSTR2 or SUBSTR4 to force all semantic calculations to be
UCS-2 or UCS-4, respectively.
SUBSTRB Calculates the length of a string in bytes.
SUBSTR2 Calculates the length of a string in UCS-2 characters, which is compliant with Java strings and
Windows client environments. Characters are represented in UCS-2 or 16-bit Unicode values.
Supplementary characters are counted as two characters.
SUBSTR4 Calculates the length of a string in UCS-4 characters. Characters are represented in UCS-4 or
32-bit Unicode values. Supplementary characters are counted as one character.
SUBSTRC Calculates the length of a string in Unicode composed characters. Supplementary characters and
composed characters are counted as one character.
Other Locale-Dependent SQL Functions
9-6 Oracle Database Globalization Support Guide
LIKE Conditions for Different Length Semantics
The LIKE conditions specify a test that uses pattern-matching. The equality operator
(=) exactly matches one character value to another, but the LIKE conditions match a
portion of one character value to another by searching the first value for the pattern
specified by the second.
LIKE calculates the length of strings in characters using the length semantics
associated with the input character set. The LIKE2, LIKE4, and LIKEC conditions are
summarized in Table 9–3.
There is no LIKEB condition.
Character Set SQL Functions
Two SQL functions, NLS_CHARSET_NAME and NLS_CHARSET_ID, can convert
between character set ID numbers and character set names. They are used by
programs that need to determine character set ID numbers for binding variables
through OCI.
Another SQL function, NLS_CHARSET_DECL_LEN, returns the declaration length of a
column in number of characters, given the byte length of the column.
This section includes the following topics:
■Converting from Character Set Number to Character Set Name
■Converting from Character Set Name to Character Set Number
■Returning the Length of an NCHAR Column
Converting from Character Set Number to Character Set Name
The NLS_CHARSET_NAME(n) function returns the name of the character set
corresponding to ID number n. The function returns NULL if n is not a recognized
character set ID value.
Converting from Character Set Name to Character Set Number
NLS_CHARSET_ID(text) returns the character set ID corresponding to the name
specified by text. text is defined as a run-time VARCHAR2 quantity, a character set
name. Values for text can be NLSRTL names that resolve to character sets that are not
the database character set or the national character set.
See Also: Oracle Database SQL Reference for more information
about the SUBSTR, LENGTH, and INSTR functions
Table 9–3 LIKE Conditions
Function Description
LIKE2 Use when characters are represented in UCS-2 semantics. A supplementary character
is considered as two characters.
LIKE4 Use when characters are represented in UCS-4 semantics. A supplementary character
is considered as one character.
LIKEC Use when characters are represented in Unicode complete character semantics. A
composed character is treated as one character.
See Also: Oracle Database SQL Reference
Other Locale-Dependent SQL Functions
SQL and PL/SQL Programming in a Global Environment 9-7
If the value CHAR_CS is entered for text, then the function returns the ID of the
database character set. If the value NCHAR_CS is entered for text, then the function
returns the ID of the database’s national character set. The function returns NULL if
text is not a recognized name.
Returning the Length of an NCHAR Column
NLS_CHARSET_DECL_LEN(BYTECNT, CSID) returns the declaration length of a
column in number of characters, given the byte length of the column. BYTECNT is the
byte length of the column. CSID is the character set ID of the column.
The NLSSORT Function
The NLSSORT function enables you to use any linguistic sort for an ORDER BY clause.
It replaces a character string with the equivalent sort string used by the linguistic sort
mechanism so that sorting the replacement strings produces the desired sorting
sequence. For a binary sort, the sort string is the same as the input string.
The kind of linguistic sort used by an ORDER BY clause is determined by the NLS_
SORT session parameter, but it can be overridden by explicitly using the NLSSORT
function.
Example 9–1 specifies a German sort with the NLS_SORT session parameter.
Example 9–1 Specifying a German Sort with the NLS_SORT Session Parameter
ALTER SESSION SET NLS_SORT = GERMAN;
SELECT * FROM table1
ORDER BY column1;
Example 9–2 Specifying a French Sort with the NLSSORT Function
This example first sets the NLS_SORT session parameter to German, but the NLSSORT
function overrides it by specifying a French sort.
ALTER SESSION SET NLS_SORT = GERMAN;
SELECT * FROM table1
ORDER BY NLSSORT(column1, 'NLS_SORT=FRENCH');
The WHERE clause uses binary comparison when NLS_COMP is set to BINARY, but this
can be overridden by using the NLSSORT function in the WHERE clause.
Example 9–3 Making a Linguistic Comparison with the WHERE Clause
ALTER SESSION SET NLS_COMP = BINARY;
SELECT * FROM table1
WHERE NLSSORT(column1, 'NLS_SORT=FRENCH')>
NLSSORT(column2, 'NLS_SORT=FRENCH');
Setting the NLS_COMP session parameter to LINGUISTIC causes the NLS_SORT value
to be used in the WHERE clause.
The rest of this section contains the following topics:
■NLSSORT Syntax
■Comparing Strings in a WHERE Clause
Note: The value for text must be entered in uppercase
characters.
Other Locale-Dependent SQL Functions
9-8 Oracle Database Globalization Support Guide
■Using the NLS_COMP Parameter to Simplify Comparisons in the WHERE Clause
■Controlling an ORDER BY Clause
NLSSORT Syntax
There are four ways to use NLSSORT:
■NLSSORT(), which relies on the NLS_SORT parameter
■NLSSORT(column1, 'NLS_SORT=xxxx')
■NLSSORT(column1, 'NLS_LANG=xxxx')
■NLSSORT(column1, 'NLS_LANGUAGE=xxxx')
The NLS_LANG parameter of the NLSSORT function is not the same as the NLS_LANG
client environment setting. In the NLSSORT function, NLS_LANG specifies the
abbreviated language name, such as US for American or PL for Polish. For example:
SELECT * FROM table1
ORDER BY NLSSORT(column1, 'NLS_LANG=PL');
Comparing Strings in a WHERE Clause
NLSSORT enables applications to perform string matching that follows alphabetic
conventions. Normally, character strings in a WHERE clause are compared by using the
binary values of the characters. One character is considered greater than another
character if it has a greater binary value in the database character set. Because the
sequence of characters based on their binary values might not match the alphabetic
sequence for a language, such comparisons may not follow alphabetic conventions.
For example, if a column (column1) contains the values ABC, ABZ, BCD, and ÄBC in
the ISO 8859-1 8-bit character set, then the following query returns both BCD and ÄBC
because Ä has a higher numeric value than B:
SELECT column1 FROM table1 WHERE column1 > 'B';
In German, Ä is sorted alphabetically before B, but in Swedish, Ä is sorted after Z.
Linguistic comparisons can be made by using NLSSORT in the WHERE clause:
WHERE NLSSORT(col) comparison_operator NLSSORT(comparison_string)
Note that NLSSORT must be on both sides of the comparison operator. For example:
SELECT column1 FROM table1 WHERE NLSSORT(column1) > NLSSORT('B');
If a German linguistic sort has been set, then the statement does not return strings
beginning with Ä because Ä comes before B in the German alphabet. If a Swedish
linguistic sort has been set, then strings beginning with Ä are returned because Ä
comes after Z in the Swedish alphabet.
Using the NLS_COMP Parameter to Simplify Comparisons in the WHERE Clause
Comparison in the WHERE clause or PL/SQL blocks is binary by default. Using the
NLSSORT function for linguistic comparison can be tedious, especially when the
linguistic sort has already been specified in the NLS_SORT session parameter. You can
use the NLS_COMP parameter to indicate that the comparisons in a WHERE clause or in
PL/SQL blocks must be linguistic according to the NLS_SORT session parameter.
Miscellaneous Topics for SQL and PL/SQL Programming in a Global Environment
SQL and PL/SQL Programming in a Global Environment 9-9
Controlling an ORDER BY Clause
If a linguistic sort is in use, then ORDER BY clauses use an implicit NLSSORT on
character data. The sort mechanism (linguistic or binary) for an ORDER BY clause is
transparent to the application. However, if the NLSSORT function is explicitly specified
in an ORDER BY clause, then the implicit NLSSORT is not done.
If a linguistic sort has been defined by the NLS_SORT session parameter, then an
ORDER BY clause in an application uses an implicit NLSSORT function. If you specify
an explicit NLSSORT function, then it overrides the implicit NLSSORT function.
When the sort mechanism has been defined as linguistic, the NLSSORT function is
usually unnecessary in an ORDER BY clause.
When the sort mechanism either defaults or is defined as binary, then a query like the
following uses a binary sort:
SELECT last_name FROM employees
ORDER BY last_name;
A German linguistic sort can be obtained as follows:
SELECT last_name FROM employees
ORDER BY NLSSORT(last_name, 'NLS_SORT = GERMAN');
Miscellaneous Topics for SQL and PL/SQL Programming in a Global
Environment
This section contains the following topics:
■SQL Date Format Masks
■Calculating Week Numbers
■SQL Numeric Format Masks
■Loading External BFILE Data into LOB Columns
SQL Date Format Masks
Several format masks are provided with the TO_CHAR, TO_DATE, and TO_NUMBER
functions.
The RM (Roman Month) format element returns a month as a Roman numeral. You can
specify either upper case or lower case by using RM or rm. For example, for the date 7
Sep 2007, DD-rm-YYYY returns 07-ix-2007 and DD-RM-YYYY returns 07-IX-2007.
Note that the MON and DY format masks explicitly support month and day
abbreviations that may not be three characters in length. For example, the
Note: The NLS_COMP parameter does not affect comparison
behavior for partitioned tables. String comparisons that are based
on a VALUES LESS THAN partition are always binary.
See Also: "NLS_COMP" on page 3-30
See Also: "Using Linguistic Sorts" on page 5-2
See Also: Oracle Database SQL Reference for a complete description
of format masks
Miscellaneous Topics for SQL and PL/SQL Programming in a Global Environment
9-10 Oracle Database Globalization Support Guide
abbreviations "Lu" and "Ma" can be specified for the French "Lundi" and "Mardi",
respectively.
Calculating Week Numbers
The week numbers returned by the WW format mask are calculated according to the
following algorithm: int(dayOfYear+6)/7. This algorithm does not follow the ISO
standard (2015, 1992-06-15).
To support the ISO standard, the IW format element is provided. It returns the ISO
week number. In addition, the I, IY, IYY, and IYYY format elements, equivalent in
behavior to the Y, YY, YYY, and YYYY format elements, return the year relating to the
ISO week number.
In the ISO standard, the year relating to an ISO week number can be different from the
calendar year. For example, 1st Jan 2007 is in ISO week number 53 of 2008. A week
always starts on a Monday and ends on a Sunday. The week number is determined
according the following rules:
■If January 1 falls on a Friday, Saturday, or Sunday, then the week including
January 1 is the last week of the previous year, because most of the days in the
week belong to the previous year.
■If January 1 falls on a Monday, Tuesday, Wednesday, or Thursday, then the week is
the first week of the new year, because most of the days in the week belong to the
new year.
For example, January 1, 1991, is a Tuesday, so Monday, December 31, 1990, to Sunday,
January 6, 1991, is in week 1. Thus, the ISO week number and year for December 31,
1990, is 1, 1991. To get the ISO week number, use the IW format mask for the week
number and one of the IY formats for the year.
SQL Numeric Format Masks
Several additional format elements are provided for formatting numbers:
For Roman numerals, you can specify either upper case or lower case, using RN or rn,
respectively. The number being converted must be an integer in the range 1 to 3999.
Loading External BFILE Data into LOB Columns
The DBMS_LOB PL/SQL package can load external BFILE data into LOB columns.
Oracle Database performs character set conversion before loading the binary data into
CLOB or NCLOB columns. Thus, the BFILE data does not need to be in the same
character set as the database or national character set to work properly. The APIs
convert the data from the specified BFILE character set into the database character set
for the CLOB datatype, or the national character set for the NCLOB datatype. The
loading takes place on the server because BFILE data is not supported on the client.
Element Description Purpose
DDecimal Returns the decimal point character
GGroup Returns the group separator
LLocal currency Returns the local currency symbol
CInternational currency Returns the ISO currency symbol
RN Roman numeral Returns the number as its Roman numeral equivalent
Miscellaneous Topics for SQL and PL/SQL Programming in a Global Environment
SQL and PL/SQL Programming in a Global Environment 9-11
■Use DBMS_LOB.LOADBLOBFROMFILE to load BLOB columns.
■Use DBMS_LOB.LOADCLOBFROMFILE to load CLOB and NCLOB columns.
See Also:
■PL/SQL Packages and Types Reference
■Oracle Database Application Developer's Guide - Large Objects
Miscellaneous Topics for SQL and PL/SQL Programming in a Global Environment
9-12 Oracle Database Globalization Support Guide
OCI Programming in a Global Environment 10-1
10
OCI Programming in a Global Environment
This chapter contains information about OCI programming in a globalized
environment. This chapter includes the following topics:
■Using the OCI NLS Functions
■Specifying Character Sets in OCI
■Getting Locale Information in OCI
■Mapping Locale Information Between Oracle and Other Standards
■Manipulating Strings in OCI
■Classifying Characters in OCI
■Converting Character Sets in OCI
■OCI Messaging Functions
■lmsgen Utility
Using the OCI NLS Functions
Many OCI NLS functions accept one of the following handles:
■The environment handle
■The user session handle
The OCI environment handle is associated with the client NLS environment and
initialized 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 is associated with the server session environment. Its 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 any NLS settings associated with it
until the first transaction begins in the session. SELECT statements do not begin a
transaction.
See Also: Oracle Call Interface Programmer's Guide for detailed
information about the OCI NLS functions
Specifying Character Sets in OCI
10-2 Oracle Database Globalization Support Guide
Specifying Character Sets in OCI
Use the OCIEnvNlsCreate function to specify client-side database and national
character sets when the OCI environment is created. This function enables users to set
character set information dynamically in applications, independent of the NLS_LANG
and NLS_NCHAR initialization parameter settings. In addition, one application can
initialize several environment handles for different client environments in the same
server environment.
Any Oracle character set ID except AL16UTF16 can be specified through the
OCIEnvNlsCreate function to specify the encoding of metadata, SQL CHAR data, and
SQL NCHAR data. Use OCI_UTF16ID in the OCIEnvNlsCreate function to specify
UTF-16 data.
Getting Locale Information in OCI
An Oracle 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 complies with 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.
You can use the OCINlsGetInfo() function to retrieve the following locale
information:
Days of the week (translated)
Abbreviated days of the week (translated)
Month names (translated)
Abbreviated month names (translated)
Yes/no (translated)
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
Table 10–1 summarizes OCI functions that return locale information.
See Also: Oracle Call Interface Programmer's Guide for more
information about the OCIEnvNlsCreate function
Table 10–1 OCI Functions That Return Locale Information
Function Description
OCINlsGetInfo() Returns locale information. See preceding text.
OCINlsCharSetNameTold() Returns the Oracle character set ID for the specified Oracle character set name
Manipulating Strings in OCI
OCI Programming in a Global Environment 10-3
Mapping Locale Information Between Oracle and Other Standards
The OCINlsNameMap function maps Oracle character set names, language names, and
territory names to and from Internet Assigned Numbers Authority (IANA) and
International Organization for Standardization (ISO) names.
Manipulating Strings in OCI
Two types of data structures are supported for string manipulation:
■Native character strings
■Wide character strings
Native character strings are encoded in native Oracle character sets. Functions that
operate on native character 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 datatype is Oracle-specific and should not be confused with the
wchar_t datatype defined by the ANSI/ISO C standard. The Oracle wide character
datatype is always 4 bytes in all platforms, while the size of wchar_t depends on the
implementation and the platform. The Oracle wide character datatype normalizes
native 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 format and
the native character format.
String manipulation includes the :
■Conversion of strings between native character format and wide character format
■Character classifications
■Case conversion
■Calculations of display length
■General string manipulation, such as comparison, concatenation, and searching
Table 10–2 summarizes the OCI string manipulation functions.
OCINlsCharSetIdToName() Returns the Oracle character set name from the specified character set ID
OCINlsNumericInfoGet() Returns specified numeric information such as maximum character size
OCINlsEnvironmentVariable
Get()
Returns the character set ID from NLS_LANG or the national character set ID
from NLS_NCHAR
See Also: Oracle Call Interface Programmer's Guide
Note: The functions and descriptions in Table 10–2 that refer to
multibyte strings apply to native character strings.
Table 10–1 (Cont.) OCI Functions That Return Locale Information
Function Description
Manipulating Strings in OCI
10-4 Oracle Database Globalization Support Guide
Table 10–2 OCI String Manipulation Functions
Function Description
OCIMultiByteToWideChar() Converts an entire null-terminated string into the wchar format
OCIMultiByteInSizeToWideChar() Converts part of a string into the wchar format
OCIWideCharToMultiByte() Converts an entire null-terminated wide character string into a multibyte string
OCIWideCharInSizeToMultiByte() Converts part of a wide character string into the multibyte format
OCIWideCharToLower() Converts the wchar character 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.
OCIWideCharToUpper() Converts the wchar character 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.
OCIWideCharStrcmp() Compares two wide character strings by binary, linguistic, or case-insensitive
comparison method.
Note: The UNICODE_BINARY sort method cannot be used with
OCIWideCharStrcmp() to perform a linguistic comparison of the supplied
wide character arguments.
OCIWideCharStrncmp() Similar to OCIWideCharStrcmp(). Compares two wide character strings by
binary, linguistic, or case-insensitive comparison methods. At most len1 bytes
form str1, and len2 bytes form str2.
Note: As with OCIWideCharStrcmp(), the UNICODE_BINARY sort method
cannot be used with OOCIWideCharStrncmp() to perform a linguistic
comparison of the supplied wide character arguments.
OCIWideCharStrcat() Appends a copy of the string pointed to by wsrcstr. Then it returns the
number of characters in the resulting string.
OCIWideCharStrncat() Appends a copy of the string pointed to by wsrcstr. Then it returns the
number of characters in the resulting string. At most n characters are
appended.
OCIWideCharStrchr() Searches for the first occurrence of wc in the string pointed to by wstr. Then it
returns a pointer to the wchar if the search is successful.
OCIWideCharStrrchr() Searches for the last occurrence of wc in the string pointed to by wstr
OCIWideCharStrcpy() Copies the wchar string pointed to by wsrcstr into the array pointed to by
wdststr. Then it returns the number of characters copied.
OCIWideCharStrncpy() Copies the wchar string pointed to by wsrcstr into the array pointed to by
wdststr. Then it returns the number of characters copied. At most n
characters are copied from the array.
OCIWideCharStrlen() Computes the number of characters in the wchar string pointed to by wstr
and returns this number
OCIWideCharStrCaseConversion() Converts the wide character string pointed to by wsrcstr into the case
specified by a flag and copies the result into the array pointed to by wdststr
OCIWideCharDisplayLength() Determines the number of column positions required for wc in display
OCIWideCharMultibyteLength() Determines the number of bytes required for wc in multibyte encoding
OCIMultiByteStrcmp() Compares two multibyte strings by binary, linguistic, or case-insensitive
comparison methods
OCIMultiByteStrncmp() Compares two multibyte strings by binary, linguistic, or case-insensitive
comparison methods. At most len1 bytes form str1 and len2 bytes form
str2.
OCIMultiByteStrcat() Appends a copy of the multibyte string pointed to by srcstr
OCIMultiByteStrncat() Appends a copy of the multibyte string pointed to by srcstr. At most n bytes
from srcstr are appended to dststr.
OCIMultiByteStrcpy() Copies the multibyte string pointed to by srcstr into an array pointed to by
dststr. It returns the number of bytes copied.
OCIMultiByteStrncpy() Copies the multibyte string pointed to by srcstr into an array pointed to by
dststr. It returns the number of bytes copied. At most n bytes are copied from
the array pointed to by srcstr to the array pointed to by dststr.
Converting Character Sets in OCI
OCI Programming in a Global Environment 10-5
Classifying Characters in OCI
Table 10–3 shows the OCI character classification functions.
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.
Table 10–4 summarizes the OCI character set conversion functions.
OCIMultiByteStrlen() Returns the number of bytes in the multibyte string pointed to by str
OCIMultiByteStrnDisplayLength() Returns the number of display positions occupied by the complete characters
within the range of n bytes
OCIMultiByteStrCaseConversion() Converts part of a string from one character set to another
See Also: Oracle Call Interface Programmer’s Guide
Table 10–3 OCI Character Classification Functions
Function Description
OCIWideCharIsAlnum() Tests whether the wide character is an alphabetic letter or decimal digit
OCIWideCharIsAlpha() Tests whether the wide character is an alphabetic letter
OCIWideCharIsCntrl() Tests whether the wide character is a control character
OCIWideCharIsDigit() Tests whether the wide character is a decimal digit
OCIWideCharIsGraph() Tests whether the wide character is a graph character
OCIWideCharIsLower() Tests whether the wide character is a lowercase letter
OCIWideCharIsPrint() Tests whether the wide character is a printable character
OCIWideCharIsPunct() Tests whether the wide character is a punctuation character
OCIWideCharIsSpace() Tests whether the wide character is a space character
OCIWideCharIsUpper() Tests whether the wide character is an uppercase character
OCIWideCharIsXdigit() Tests whether the wide character is a hexadecimal digit
OCIWideCharIsSingleByte() Tests whether wc is a single-byte character when converted into multibyte
See Also: Oracle Call Interface Programmer’s Guide
Table 10–4 OCI Character Set Conversion Functions
Function Description
OCICharSetToUnicode() Converts a multibyte string pointed to by src to Unicode into the
array pointed to by dst
OCIUnicodeToCharSet() Converts a Unicode string pointed to by src to multibyte into the
array pointed to by dst
OCINlsCharSetConvert() Converts a string from one character set to another
OCICharSetConversionIsReplacementUsed() Indicates whether replacement characters were used for
characters that could not be converted in the last invocation of
OCINlsCharSetConvert() or OCIUnicodeToCharSet()
Table 10–2 (Cont.) OCI String Manipulation Functions
Function Description
OCI Messaging Functions
10-6 Oracle Database Globalization Support Guide
OCI Messaging Functions
The user message API provides a simple interface for cartridge developers to retrieve
their own messages as well as Oracle messages.
Table 10–5 summarizes the OCI messaging functions.
lmsgen Utility
Purpose
The lmsgen utility converts text-based message files (.msg) into binary format (.msb)
so that Oracle messages and OCI messages provided by the user can be returned to
OCI functions in the desired language.
Messages used by the server are stored in binary-format files that are placed in the
$ORACLE_HOME/product_name/mesg directory, or the equivalent for your
operating system. Multiple versions of these files can exist, one for each supported
language, using the following filename convention:
<product_id><language_abbrev>.msb
For example, the file containing the server messages in French is called oraf.msb,
because ORA is the product ID (<product_id>) and F is the language abbreviation
(<language_abbrev>) for French. The value for product_name is rdbms, so it is in
the $ORACLE_HOME/rdbms/mesg directory.
Syntax
LMSGEN text_file product facility [language] [-i indir] [-o outdir]
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.
indir is the optional directory to specify the text file location.
outdir is the optional directory to specify the output file location.
See Also:
■Oracle Call Interface Programmer’s Guide
■"OCI Programming with Unicode" on page 7-10
Table 10–5 OCI Messaging Functions
Function Description
OCIMessageOpen() Opens a message handle in a language pointed to by hndl
OCIMessageGet() Retrieves a message with message number identified by msgno. If the buffer
is not zero, then the function copies the message into the buffer specified by
msgbuf.
OCIMessageClose() Closes a message handle pointed to by msgh and frees any memory associated
with this handle
See Also: Oracle Data Cartridge Developer's Guide
lmsgen Utility
OCI Programming in a Global Environment 10-7
The output (.msb) file will be generated under the $ORACLE_HOME/product/mesg/
directory.
Text Message Files
Text message files must follow these guidelines:
■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. Use 0.
The message text cannot be longer than 511 bytes.
The following example shows an Oracle message text file:
/ Copyright (c) 2006 by Oracle. 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)"
Example: Creating a Binary Message File from a Text Message File
The following table contains sample values for the lmsgen parameters:
One of the lines in the text message file is the following:
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. The directory $ORACLE_HOME/myapp/mesg
must already exist.
% lmsgen impus.msg myapp imp AMERICAN
The following output results:
Generating message file impus.msg -->
$ORACLE_HOME/myapp/mesg/impus.msb
NLS Binary Message File Generation Utility: Version 10.2.0.1.0 - Production
Copyright (c) Oracle 1979, 2006. All rights reserved.
Parameter Value
product myapp
facility imp
language AMERICAN
text_file impus.msg
lmsgen Utility
10-8 Oracle Database Globalization Support Guide
CORE 10.2.0.1.0 Production
Character Set Migration 11-1
11
Character Set Migration
This chapter discusses character set conversion and character set migration. This
chapter includes the following topics:
■Overview of Character Set Migration
■Changing the Database Character Set of an Existing Database
■Migrating to NCHAR Datatypes
■Tasks to Recover Database Schema After Character Set Migration
Overview of Character Set Migration
Choosing the appropriate character set for your database is an important decision.
When you choose the database character set, consider the following factors:
■The type of data you need to store
■The languages that the database needs to accommodate now and in the future
■The different size requirements of each character set and the corresponding
performance implications
A related topic is choosing a new character set for an existing database. Changing the
database character set for an existing database is called character set migration. When
you migrate from one database character set to another you must choose an
appropriate character set. You should also plan to minimize data loss from the
following sources:
■Data Truncation
■Character Set Conversion Issues
Data Truncation
When the database is created using byte semantics, the sizes of the CHAR and
VARCHAR2 datatypes are specified in bytes, not characters. For example, the
specification CHAR(20) in a table definition allows 20 bytes for storing character data.
When the database character set uses a single-byte character encoding scheme, no data
loss occurs when characters are stored because the number of characters is equivalent
to the number of bytes. If the database character set uses a multibyte character set,
then the number of bytes no longer equals the number of characters because a
character can consist of one or more bytes.
See Also: Chapter 2, "Choosing a Character Set"
Overview of Character Set Migration
11-2 Oracle Database Globalization Support Guide
During migration to a new character set, it is important to verify the column widths of
existing CHAR and VARCHAR2 columns because they may need to be extended to
support an encoding that requires multibyte storage. Truncation of data can occur if
conversion causes expansion of data.
Table 11–1 shows an example of data expansion when single-byte characters become
multibyte characters through conversion.
The first column of Table 11–1 shows selected characters. The second column shows
the hexadecimal representation of the characters in the WE8MSWIN1252 character set.
The third column shows the hexadecimal representation of each character in the
AL32UTF8 character set. Each pair of letters and numbers represents one byte. For
example, ä (a with an umlaut) is a single-byte character (E4) in WE8MSWIN1252, but
it becomes a two-byte character (C3 A4) in AL32UTF8. Also, the encoding for the euro
symbol expands from one byte (80) to three bytes (E2 82 AC).
If the data in the new character set requires storage that is greater than the supported
byte size of the datatypes, then you need to change your schema. You may need to use
CLOB columns.
Additional Problems Caused by Data Truncation
Data truncation can cause the following problems:
■In the database data dictionary, schema object names cannot exceed 30 bytes in
length. You must rename schema objects if their names exceed 30 bytes in the new
database character set. For example, one Thai character in the Thai national
character set requires 1 byte. In AL32UTF8, it requires 3 bytes. If you have defined
a table whose name is 11 Thai characters, then the table name must be shortened to
10 or fewer Thai characters when you change the database character set to
AL32UTF8.
■If existing Oracle usernames or passwords are created based on characters that
change in size in the new character set, then users will have trouble logging in
because of authentication failures after the migration to a new character set. This
occurs because the encrypted usernames and passwords stored in the data
dictionary may not be updated during migration to a new character set. For
example, if the current database character set is WE8MSWIN1252 and the new
database character set is AL32UTF8, then the length of the username scött (o
with an umlaut) changes from 5 bytes to 6 bytes. In AL32UTF8, scött can no
longer log in because of the difference in the username. Oracle recommends that
usernames and passwords be based on ASCII characters. If they are not, then you
must reset the affected usernames and passwords after migrating to a new
character set
Table 11–1 Single-Byte and Multibyte Encoding
Character WE8MSWIN 1252 Encoding AL32UTF8 Encoding
äE4C3 A4
öF6C3 B6
©A9C2 A9
€80 E2 82 AC
See Also: "Length Semantics" on page 2-8
Overview of Character Set Migration
Character Set Migration 11-3
■When CHAR data contains characters that expand after migration to a new
character set, space padding is not removed during database export by default.
This means that these rows will be rejected upon import into the database with the
new character set. The workaround is to set the BLANK_TRIMMING initialization
parameter to TRUE before importing the CHAR data.
Character Set Conversion Issues
This section includes the following topics:
■Replacement Characters that Result from Using the Export and Import Utilities
■Invalid Data That Results from Setting the Client's NLS_LANG Parameter
Incorrectly
■Conversion from Single-byte to Multibyte Character Set and Oracle Data Pump
Replacement Characters that Result from Using the Export and Import Utilities
The Export and Import utilities can convert character sets from the original database
character set to the new database character set. However, character set conversions can
sometimes cause data loss or data corruption. For example, if you are migrating from
character set A to character set B, then the destination character set B should be a
superset of character set A. The destination character, B, is a superset if it contains all
the characters defined in character set A. Characters that are not available in character
set B are converted to replacement characters, which are often specified as ? or ¿ or as
a character that is related to the unavailable character. For example, ä (a with an
umlaut) can be replaced by a. Replacement characters are defined by the target
character set.
Figure 11–1 shows an example of a character set conversion in which the copyright
and euro symbols are converted to ? and ä is converted to a.
Note: Encrypted usernames and passwords stored in the data
dictionary are not updated when migration is accomplished with
the CSALTER script, but they are updated if the migration is
accomplished with the Import and Export utilities.
See Also: Oracle Database Reference for more information about the
BLANK_TRIMMING initialization parameter
Note: There is an exception to the requirement that the destination
character set B should be a superset of character set A. If your data
contains no characters that are in character set A but are not in
character set B, then the destination character set does not need to
be a superset of character set A to avoid data loss or data
corruption.
Overview of Character Set Migration
11-4 Oracle Database Globalization Support Guide
Figure 11–1 Replacement Characters in Character Set Conversion
To reduce the risk of losing data, choose a destination character set with a similar
character repertoire. Migrating to Unicode may be the best option, because AL32UTF8
contains characters from most legacy character sets.
Invalid Data That Results from Setting the Client's NLS_LANG Parameter
Incorrectly
Another character set migration scenario that can cause the loss of data is migrating a
database that contains invalid data. Invalid data usually occurs in a database because
the NLS_LANG parameter is not set properly on the client. The NLS_LANG value should
reflect the client operating system code page. For example, in an English Windows
environment, the code page is WE8MSWIN1252. When the NLS_LANG parameter is set
properly, the database can automatically convert incoming data from the client
operating system. When the NLS_LANG parameter is not set properly, then the data
coming into the database is not converted properly. For example, suppose that the
database character set is AL32UTF8, the client is an English Windows operating
system, and the NLS_LANG setting on the client is AL32UTF8. Data coming into the
database is encoded in WE8MSWIN1252 and is not converted to AL32UTF8 data
because the NLS_LANG setting on the client matches the database character set. Thus
Oracle assumes that no conversion is necessary, and invalid data is entered into the
database.
This can lead to two possible data inconsistency problems. One problem occurs when
a database contains data from a character set that is different from the database
character set but the same code points exist in both character sets. For example, if the
database character set is WE8ISO8859P1 and the NLS_LANG setting of the Chinese
Windows NT client is SIMPLIFIED CHINESE_CHINA.WE8ISO8859P1, then all
multibyte Chinese data (from the ZHS16GBK character set) is stored as multiples of
single-byte WE8ISO8859P1 data. This means that Oracle treats these characters as
single-byte WE8ISO8859P1 characters. Hence all SQL string manipulation functions
such as SUBSTR or LENGTH are based on bytes rather than characters. All bytes
constituting ZHS16GBK data are legal WE8ISO8859P1 codes. If such a database is
migrated to another character set such as AL32UTF8, then character codes are
converted as if they were in WE8ISO8859P1. This way, each of the two bytes of a
ZHS16GBK character are converted separately, yielding meaningless values in
AL32UTF8. Figure 11–2 shows an example of this incorrect character set replacement.
Character Set
A
a
b
c
?
Character Set
B
Overview of Character Set Migration
Character Set Migration 11-5
Figure 11–2 Incorrect Character Set Replacement
The second possible problem is having data from mixed character sets inside the
database. For example, if the data character set is WE8MSWIN1252, and two separate
Windows clients using German and Greek are both using WE8MSWIN1252 as the
NLS_LANG character set, then the database contains a mixture of German and Greek
characters. Figure 11–3 shows how different clients can use different character sets in
the same database.
Figure 11–3 Mixed Character Sets
For database character set migration to be successful, both of these cases require
manual intervention because Oracle Database cannot determine the character sets of
the data being stored. Incorrect data conversion can lead to data corruption, so
perform a full backup of the database before attempting to migrate the data to a new
character set.
Conversion from Single-byte to Multibyte Character Set and Oracle Data Pump
If Oracle Data Pump is being used, and if a character set migration from single-byte to
multibyte is performed, then the Data Pump PL/SQL packages must be reloaded.
Simplified Chinese
Windows NT
(WE8ISO8859P1)
Database Server
(WE8ISO8859P1)
0xB1 0xED OxB1ED
Greek Windows
Database Server
(WE8MSWIN1252)
0xE4 0xF6
= 0xE4
= 0xF6
German Windows
= 0xE4
= 0xF6
Changing the Database Character Set of an Existing Database
11-6 Oracle Database Globalization Support Guide
Changing the Database Character Set of an Existing Database
Database character set migration has two stages: data scanning and data conversion.
Before you change the database character set, you need to identify possible database
character set conversion problems and truncation of data. This step is called data
scanning.
Data scanning identifies the amount of effort required to migrate data into the new
character encoding scheme before changing the database character set. Some examples
of what may be found during a data scan are the number of schema objects where the
column widths need to be expanded and the extent of the data that does not exist in
the target character repertoire. This information helps to determine the best approach
for converting the database character set.
Incorrect data conversion can lead to data corruption, so perform a full backup of the
database before attempting to migrate the data to a new character set.
There are three approaches to converting data from one database character set to
another if the database does not contain any of the inconsistencies described in
"Character Set Conversion Issues" on page 11-3. A description of methods to migrate
databases with such inconsistencies is out of the scope of this documentation. For
more information, contact Oracle Consulting Services for assistance.
The approaches are:
■Migrating Character Data Using a Full Export and Import
■Migrating a Character Set Using the CSALTER Script
■Migrating Character Data Using the CSALTER Script and Selective Imports
Migrating Character Data Using a Full Export and Import
In most cases, a full export and import is recommended to properly convert all data to
a new character set. It is important to be aware of data truncation issues, because
columns with character datatypes may need to be extended before the import to
handle an increase in size. Existing PL/SQL code should be reviewed to ensure that all
byte-based SQL functions such as LENGTHB, SUBSTRB, and INSTRB, and PL/SQL
CHAR and VARCHAR2 declarations are still valid.
Migrating a Character Set Using the CSALTER Script
The CSALTER script is part of the Database Character Set Scanner utility. The CSALTER
script is the most straightforward way to migrate a character set, but it can be used
only if all of the schema data is a strict subset of the new character set. The new
character set is a strict superset of the current character set if:
■Each and every character in the current character set is available in the new
character set.
■Each and every character in the current character set has the same code point
value in the new character set. For example, many character sets are strict
supersets of US7ASCII.
See Also: Chapter 12, "Character Set Scanner Utilities" for more
information about data scanning
See Also: Oracle Database Utilities for more information about the
Export and Import utilities
Changing the Database Character Set of an Existing Database
Character Set Migration 11-7
With the strict superset criteria in mind, only the metadata is converted to the new
character set by the CSALTER script, with the following exception: the CSALTER script
performs data conversion only on CLOB columns in the data dictionary and sample
schemas that have been created by Oracle. CLOB columns that users have created may
need to be handled separately. Beginning with Oracle9i, some internal fields in the
data dictionary and sample schemas are stored in CLOB columns. Customers may also
store data in CLOB fields. When the database character set is multibyte, then CLOB data
is stored in a format that is compatible with UCS-2 data. When the database character
set is single-byte, then CLOB data is stored using the database character set. Because
the CSALTER script converts data only in CLOB columns in the data dictionary and
sample schemas that were created by Oracle, any other CLOB columns that are created
must be first exported and then dropped from the schema before the CSALTER script
can be run.
To change the database character set, perform the following steps:
1. Shut down the database, using either a SHUTDOWN IMMEDIATE or a SHUTDOWN
NORMAL statement.
2. Do a full backup of the database, because the CSALTER script cannot be rolled
back.
3. Start up the database.
4. Run the Database Character Set Scanner utility.
CSSCAN /AS SYSDBA FULL=Y...
5. Run the CSALTER script.
@@CSALTER.PLB
SHUTDOWN IMMEDIATE; -- or SHUTDOWN NORMAL;
STARTUP;
Note that the CSALTER script does not perform any user data conversion. It only
changes the character set metadata in the data dictionary.Thus, after the CSALTER
operation, Oracle will behave as if the database was created using the new character
set.
Using the CSALTER Script in an Oracle Real Application Clusters Environment
In an Oracle Real Application Clusters environment, ensure that no other Oracle
background processes are running, with the exception of the background processes
associated with the instance through which a user is connected, before attempting to
issue the CSALTER script. With DBA privileges, use the following SQL statement to
verify that no other Oracle background processes are running:
SELECT SID, SERIAL#, PROGRAM FROM V$SESSION;
Set the CLUSTER_DATABASE initialization parameter to FALSE to allow the character
set change to be completed. Reset it to TRUE after the character set has been changed.
See Also:
■"Migrating Character Data Using the CSALTER Script and
Selective Imports" on page 11-8
■"Database Character Set Scanner CSALTER Script" on
page 12-37
Migrating to NCHAR Datatypes
11-8 Oracle Database Globalization Support Guide
Migrating Character Data Using the CSALTER Script and Selective Imports
Another approach to migrating character data is to perform selective exports followed
by rescanning and running the CSALTER script. This approach is most common when
the subset character set is single-byte and the migration is to a multibyte character set.
In this scenario, user-created CLOBs must be converted because the encoding changes
from the single- byte character set to a UCS-2-compatible format which Oracle uses for
storage of CLOBs regardless of the multibyte encoding. The Database Character Set
Scanner identifies these columns as convertible. It is up to the user to export these
columns and then drop them from the schema, rescan, and, if the remaining data is
clean, run the CSALTER script. When these steps have been completed, then import the
CLOB columns to the database to complete migration.
Migrating to NCHAR Datatypes
In Oracle Database, data that is stored in columns of the NCHAR datatypes is stored
exclusively in a Unicode encoding regardless of the database character set. This
enables users to store Unicode in a database that does not use Unicode as the database
character set.
This section includes the following topics:
■Migrating Version 8 NCHAR Columns to Oracle9i and Later
■Changing the National Character Set
■Migrating CHAR Columns to NCHAR Columns
Migrating Version 8 NCHAR Columns to Oracle9i and Later
In version 8 of Oracle Database, Oracle introduced a national character datatype
(NCHAR) that enables a second, alternative character set in addition to the database
character set. The NCHAR datatypes support several fixed-width Asian character sets
that were introduced to provide better performance when processing Asian character
data.
Beginning with Oracle9i, the SQL NCHAR datatypes are limited to Unicode character
set encoding (UTF8 and AL16UTF16). Any other version 8 character sets that were
available for the NCHAR datatypes, including Asian character sets such as
JA16SJISFIXED are no longer supported.
The steps for migrating existing NCHAR, NVARCHAR2, and NCLOB columns to NCHAR
datatypes in Oracle9i and later are as follows:
1. Export all NCHAR columns from the version 8 or Oracle8i database.
2. Drop the NCHAR columns.
3. Upgrade the database to the later release.
4. Import the NCHAR columns into the upgraded database.
The migration utility can also convert version 8 and Oracle8i NCHAR columns to NCHAR
columns in later releases. A SQL NCHAR upgrade script called utlnchar.sql is
supplied with the migration utility. Run it at the end of the database migration to
convert version 8 and Oracle8i NCHAR columns to the NCHAR columns in later releases.
After the script has been executed, the data cannot be downgraded. The only way to
move back to version 8 or Oracle8i is to drop all NCHAR columns, downgrade the
database, and import the old NCHAR data from a previous version 8 or Oracle8i export
file. Ensure that you have a backup (export file) of version 8 or Oracle8i NCHAR data, in
case you need to downgrade your database in the future.
Migrating to NCHAR Datatypes
Character Set Migration 11-9
Changing the National Character Set
Use the CSALTER script to change the national character set.
Migrating CHAR Columns to NCHAR Columns
You can change a column's datatype definition using the following methods:
■The ALTER TABLE MODIFY statement
■Online table redefinition
The ALTER TABLE MODIFY statement has the following advantages over online table
redefinition:
■Easier to use
■Fewer restrictions
Online table redefinition has the following advantages over the ALTER TABLE
MODIFY statement:
■Faster for columns with a large amount of data
■Can migrate several columns at one time
■Table is available for DML during most of the migration process
■Avoids table fragmentation, which saves space and allows faster access to data.
■Can be used for migration from the CLOB datatype to the NCLOB datatype
This section contains the following topics:
■Using the ALTER TABLE MODIFY Statement to Change CHAR Columns to
NCHAR Columns
■Using Online Table Redefinition to Migrate a Large Table to Unicode
Using the ALTER TABLE MODIFY Statement to Change CHAR Columns to NCHAR
Columns
The ALTER TABLE MODIFY statement can be used to change table column definitions
from the CHAR datatypes to NCHAR datatypes. It also converts all of the data in the
column from the database character set to the NCHAR character set. The syntax of the
ALTER TABLE MODIFY statement is as follows:
ALTER TABLE table_name MODIFY (column_name datatype);
If indexes have been built on the migrating column, then dropping the indexes can
improve the performance of the ALTER TABLE MODIFY statement because indexes
are updated when each row is updated.
The maximum column lengths for NCHAR and NVARCHAR2 columns are 2000 and 4000
bytes. When the NCHAR character set is AL16UTF16, the maximum column lengths for
See Also:
■Oracle Database Utilities for a description of export and import
procedures
■Oracle Database Upgrade Guide for NCHAR migration information
See Also: Chapter 12, "Character Set Scanner Utilities" for the
syntax of the CSALTER script
Migrating to NCHAR Datatypes
11-10 Oracle Database Globalization Support Guide
NCHAR and NVARCHAR2 columns are 1000 and 2000 characters, which are 2000 and
4000 bytes. If this size limit is violated during migration, then consider changing the
column to the NCLOB datatype instead.
Using Online Table Redefinition to Migrate a Large Table to Unicode
It takes significant time to migrate a large table with a large number of rows to
Unicode datatypes. During the migration, the column data is unavailable for both
reading and updating. Online table redefinition can significantly reduce migration
time. Using online table redefinition also allows the table to be accessible to DML
during most of the migration time.
Perform the following tasks to migrate a table to Unicode datatypes using online table
redefinition:
1. Use the DBMS_REDEFINITION.CAN_REDEF_TABLE PL/SQL procedure to verify
that the table can be redefined online. For example, to migrate the scott.emp
table, enter the following command:
DBMS_REDEFINITION.CAN_REDEF_TABLE('scott','emp');
2. Create an empty interim table in the same schema as the table that is to be
redefined. Create it with NCHAR datatypes as the attributes. For example, enter a
statement similar to the following:
CREATE TABLE int_emp(
empno NUMBER(4),
ename NVARCHAR2(10),
job NVARCHAR2(9),
mgr NUMBER(4),
hiredate DATE,
sal NUMBER(7,2),
deptno NUMBER(2),
org NVARCHAR2(10));
3. Start the online table redefinition. Enter a command similar to the following:
DBMS_REDEFINITION.START_REDEF_TABLE('scott',
'emp',
'int_emp',
'empno empno,
to_nchar(ename) ename,
to_nchar(job) job,
mgr mgr,
hiredate hiredate,
sal sal,
deptno deptno,
to_nchar(org) org');
If you are migrating CLOB columns to NCLOB columns, then use the TO_NCLOB
SQL conversion function instead of the TO_NCHAR SQL function.
Note: CLOB columns cannot be migrated to NCLOB columns using
the ALTER TABLE MODIFY statement. Use online table
redefinition to change a column from the CLOB datatype to the
NCLOB datatype.
See Also: "Using Online Table Redefinition to Migrate a Large
Table to Unicode" on page 11-10
Tasks to Recover Database Schema After Character Set Migration
Character Set Migration 11-11
4. Create triggers, indexes, grants, and constraints on the interim table. Referential
constraints that apply to the interim table (the interim table is a parent or child
table of the referential constraint) must be created in DISABLED mode. Triggers
that are defined on the interim table are not executed until the online table
redefinition process has been completed.
5. You can synchronize the interim table with the original table. If many DML
operations have been applied to the original table since the online redefinition
began, then execute the DBMS_REDEFINITION.SYNC_INTERIM_TABLE
procedure. This reduces the time required for the DBMS_
REDEFINITION.FINISH_REDEF_TABLE procedure. Enter a command similar to
the following:
DBMS_REDEFINITION.SYNC_INTERIM_TABLE('scott', 'emp', 'int_emp');
6. Execute the DBMS_REDEFINITION.FINISH_REDEF_TABLE procedure. Enter a
command similar to the following:
DBMS_REDEFINITION.RINISH_REDEF_TABLE('scott', 'emp', 'int_emp');
When this procedure has been completed, the following conditions are true:
■The original table is redefined so that it has all the attributes, indexes,
constraints, grants, and triggers of the interim table.
■The referential constraints that apply to the interim table apply to the
redefined original table.
7. Drop the interim table. Enter a statement similar to the following:
DROP TABLE int_emp;
The results of the online table redefinition tasks are as follows:
■The original table is migrated to Unicode columns.
■The triggers, grants, indexes, and constraints defined on the interim table after the
START_REDEF_TABLE subprogram and before the FINISH_REDEF_TABLE
subprogram are defined for the redefined original table. Referential constraints
that apply to the interim table now apply to the redefined original table and are
enabled.
■The triggers, grants, indexes, and constraints defined on the original table before
redefinition are transferred to the interim table and are dropped when you drop
the interim table. Referential constraints that applied to the original table before
redefinition were applied to the interim table and are now disabled.
■PL/SQL procedures and cursors that were defined on the original table before
redefinition are invalidated. They are automatically revalidated the next time they
are used. Revalidation may fail because the table definition has changed.
Tasks to Recover Database Schema After Character Set Migration
You may need to perform additional tasks to recover a migrated database schema to its
original state. Consider the issues described in Table 11–2.
See Also: Oracle Database Administrator's Guide for more
information about online table redefinition
Tasks to Recover Database Schema After Character Set Migration
11-12 Oracle Database Globalization Support Guide
Table 11–2 Issues During Recovery of a Migrated Database Schema
Issue Description
Indexes When table columns are changed from CHAR datatypes to NCHAR datatypes by the ALTER
TABLE MODIFY statement, indexes that are built on the columns are changed automatically by
the database. This slows down performance for the ALTER TABLE MODIFY statement. If you
drop indexes before issuing the ALTER TABLE MODIFY statement, then re-create them after
migration.
Constraints If you disable constraints before migration, then re-enable them after migration.
Triggers If you disable triggers before migration, then re-enable them after migration.
Replication If the columns that are migrated to Unicode datatypes are replicated across several sites, then
the changes should be executed at the master definition site. Then they are propagated to the
other sites.
Binary order The migration from CHAR datatypes to NCHAR datatypes involves character set conversion if
the database and NCHAR data have different character sets. The binary order of the same data
in different encodings can be different. This affects applications that rely on binary order.
Character Set Scanner Utilities 12-1
12
Character Set Scanner Utilities
This chapter introduces the Language and Character Set File Scanner and the Database
Character Set Scanner. The character set scanner utilities are tools for detecting and
verifying valid and invalid data. The Language and Character Set File Scanner
supports text files, while the Database Character Set Scanner scans data inside the
database.
This chapter contains these topics:
■The Language and Character Set File Scanner
■The Database Character Set Scanner
■Scan Modes in the Database Character Set Scanner
■Installing and Starting the Database Character Set Scanner
■Database Character Set Scanner Parameters
■Database Character Set Scanner Sessions: Examples
■Database Character Set Scanner Reports
■How to Handle Convertible or Lossy Data in the Data Dictionary
■Storage and Performance Considerations in the Database Character Set Scanner
■Database Character Set Scanner CSALTER Script
■Database Character Set Scanner Views
■Database Character Set Scanner Error Messages
The Language and Character Set File Scanner
The Language and Character Set File Scanner (LCSSCAN) is a high-performance,
statistically based utility for determining the language and character set for unknown
file text. It can automatically identify a wide variety of language and character set
pairs. With each text, the language and character set detection engine sets up a series
of probabilities, each probability corresponding to a language and character set pair.
The most statistically probable pair identifies the dominant language and character set.
The purity of the text affects the accuracy of the language and character set detection.
The ideal case is literary text of one single language with no spelling or grammatical
errors. These types of text may require 100 characters of data or more and can return
results with a very high factor of confidence. On the other hand, some technical
documents can require longer segments before they are recognized. Documents that
contain a mix of languages or character sets or text such as addresses, phone numbers,
or programming language code may yield poor results. For example, if a document
The Language and Character Set File Scanner
12-2 Oracle Database Globalization Support Guide
has both French and German embedded, then the accuracy of guessing either
language successfully is statistically reduced. Both plain text and HTML files are
accepted. If the format is known, you should set the FORMAT parameter to improve
accuracy.
This section includes the following topics:
■Syntax of the LCSSCAN Command
■Examples: Using the LCSSCAN Command
■Getting Command-Line Help for the Language and Character Set File Scanner
■Supported Languages and Character Sets
■LCSSCAN Error Messages
Syntax of the LCSSCAN Command
Start the Language and Character Set File Scanner with the LCSSCAN command. Its
syntax is as follows:
LCSSCAN [RESULTS=number] [FORMAT=file_type] [BEGIN=number] [END=number]
FILE=file_name
The parameters are described in the rest of this section.
RESULTS
The RESULTS parameter is optional.
FORMAT
The FORMAT paramater is optional.
BEGIN
The BEGIN parameter is optional.
Property Description
Default value 1
Minimum value 1
Maximum value 3
Purpose The number of language and character set pairs that are returned.
They are listed in order of probability. The comparative weight of
the first choice cannot be quantified. The recommended value for
this parameter is the default value of 1.
Property Description
Default Value text
Purpose This parameter identifies the type of file to be scanned. The possible
values are html, text, and auto.
Property Description
Default value 1
Minimum value 1
The Language and Character Set File Scanner
Character Set Scanner Utilities 12-3
END
The END parameter is optional.
FILE
The FILE parameter is required.
Examples: Using the LCSSCAN Command
Example 12–1 Specifying Only the File Name in the LCSSCAN Command
LCSSCAN FILE=example.txt
In this example, the entire example.txt file is scanned because the BEGIN and END
parameters have not been specified. One language and character set pair will be
returned because the RESULTS parameter has not been specified.
Example 12–2 Specifying the Format as HTML
LCSSCAN FILE=example.html FORMAT=html
In this example, the entire example.html file is scanned because the BEGIN and END
parameters have not been specified. The scan will strip HTML tags before the scan,
thus results are more accurate. One language and character set pair will be returned
because the RESULTS parameter has not been specified.
Example 12–3 Specifying the RESULTS and BEGIN Parameters for LCSSCAN
LCSSCAN RESULTS=2 BEGIN=50 FILE=example.txt
The scanning process starts at the 50th byte of the file and continues to the end of the
file. Two language and character set pairs will be returned.
Example 12–4 Specifying the RESULTS and END Parameters for LCSSCAN
LCSSCAN RESULTS=3 END=100 FILE=example.txt
Maximum value Number of bytes in file
Purpose The byte of the input file where LCSSCAN begins the scanning
process. The default value is the first byte of the input file.
Property Description
Default value End of file
Minimum value 3
Maximum value Number of bytes in file
Purpose The last byte of the input file that LCSSCAN scans. The default value
is the last byte of the input file.
Property Description
Default value None
Purpose Specifies the name of a text file to be scanned
Property Description
The Language and Character Set File Scanner
12-4 Oracle Database Globalization Support Guide
The scanning process starts at the beginning of the file and ends at the 100th byte of
the file. Three language and character set pairs will be returned.
Example 12–5 Specifying the BEGIN and END Parameters for LCSSCAN
LCSSCAN BEGIN=50 END=100 FILE=example.txt
The scanning process starts at the 50th byte and ends at the 100th byte of the file. One
language and character set pair will be returned because the RESULTS parameter has
not been specified.
Getting Command-Line Help for the Language and Character Set File Scanner
To obtain a summary of the Language and Character Set File Scanner parameters,
enter the following command:
LCSSCAN HELP=y
The resulting output shows a summary of the Language and Character Set Scanner
parameters.
Supported Languages and Character Sets
The Language and Character Set File Scanner supports several character sets for each
language.
When the binary values for a language match two or more encodings that have a
subset/superset relationship, the subset character set is returned. For example, if the
language is German and all characters are 7-bit, then US7ASCII is returned instead of
WE8MSWIN1252, WE8ISO8859P15, or WE8ISO8859P1.
When the character set is determined to be UTF-8, the Oracle character set UTF8 is
returned by default unless 4-byte characters (supplementary characters) are detected
within the text. If 4-byte characters are detected, then the character set is reported as
AL32UTF8.
LCSSCAN Error Messages
LCD-00001 An unknown error occured.
Cause: An error occurred accessing an internal structure.
Action: Report this error to Oracle Support.
LCD-00002 NLS data could not be loaded.
Cause: An error occurred accessing $ORACLE_HOME/nls/data.
Action: Check to make sure $ORACLE_HOME/nls/data exists and is accessible.
If not found check $ORA_NLS10 directory.
LCD-00003 An error occurred while reading the profile file.
Cause: An error occurred accessing $ORACLE_HOME/nls/data.
Action: Check to make sure $ORACLE_HOME/nls/data exists and is accessible.
If not found check $ORA_NLS10 directory.
LCD-00004 The beginning or ending offset has been set incorrectly.
See Also: "Language and Character Set Detection Support" on
page A-18 for a list of supported languages and character sets
The Database Character Set Scanner
Character Set Scanner Utilities 12-5
Cause: The beginning and ending offsets must be an integer greater than 0.
Action: Change the offset to a positive number.
LCD-00005 The ending offset has been set incorrectly.
Cause: The ending offset must be greater than the beginning offset.
Action: Change the ending offset to be greater than the beginning offset.
LCD-00006 An error occurred when opening the input file.
Cause: The file was not found or could not be opened.
Action: Check the name of the file specified. Make sure the full file name is
specified and that the file is not in use.
LCD-00007 The beginning offset has been set incorrectly.
Cause: The beginning offset must be less than the number of bytes in the file.
Action: Check the size of the file and specify a smaller beginning offset.
LCD-00008 No result was returned.
Cause: Not enough text was inputted to produce a result.
Action: A larger sample of text needs to be inputted to produce a reliable result.
The Database Character Set Scanner
The Database Character Set Scanner assesses the feasibility of migrating an Oracle
database to a new database character set. The Database Character Set Scanner checks
all character data in the database and tests for the effects and problems of changing the
character set encoding. A summary report is generated at the end of the scan that
shows the scope of work required to convert the database to a new character set.
Based on the information in the summary report, you can decide on the most
appropriate method to migrate the database's character set. The methods are:
■Export and Import utilities
■CSALTER script
■CSALTER script with Export and Import utilities on selected tables
Conversion Tests on Character Data
The Database Character Set Scanner reads the character data and tests for the
following conditions on each data cell:
Note: If the Database Character Set Scanner shows conversion
exceptions, then these problems must be fixed before using any of
the described methods. This may involve further data analysis and
modifying the problem data to eliminate those exceptions. In
extreme cases, both the database and the application might need to
be modified. Oracle recommends you contact Oracle Consulting
Services for services in database character set migration.
See Also: "Changing the Database Character Set of an Existing
Database" on page 11-6
Scan Modes in the Database Character Set Scanner
12-6 Oracle Database Globalization Support Guide
■Do character code points of the data cells change when converted to the new
character set?
■Can the data cells be successfully converted to the new character set?
■Will the post-conversion data fit into the current column size?
The Database Character Set Scanner reads and tests for data in CHAR, VARCHAR2,
LONG, CLOB, NCHAR, NVARCHAR2, NCLOB and VARRAY columns as well as nested
tables. The Database Character Set Scanner does not perform post-conversion column
size testing for LONG, CLOB, and NCLOB columns.
Scan Modes in the Database Character Set Scanner
The Database Character Set Scanner provides four modes of database scan:
■Full Database Scan
■User Scan
■Table Scan
■Column Scan
Full Database Scan
The Database Character Set Scanner reads and verifies the character data of all tables
belonging to all users in the database including the data dictionary (such as SYS and
SYSTEM users), and it reports on the effects of the simulated migration to the new
database character set. It scans all schema objects including stored packages,
procedures and functions, and object definitions stored as part of the data dictionary.
To understand the feasibility of migrating your database to a new database character
set, you need to perform a full database scan.
User Scan
The Database Character Set Scanner reads and verifies character data of all tables
belonging to the specified user and reports on the effects on the tables of changing the
character set.
Table Scan
The Database Character Set Scanner reads and verifies the character data of the
specified tables, and reports the effects on the tables of changing the character set.
Column Scan
The Database Character Set Scanner reads and verifies the character data of the
specified columns, and reports the effects on the tables of changing the character set.
Installing and Starting the Database Character Set Scanner
This section describes how to install and start the Database Character Set Scanner. It
includes the following topics:
■Access Privileges for the Database Character Set Scanner
■Installing the Database Character Set Scanner System Tables
Installing and Starting the Database Character Set Scanner
Character Set Scanner Utilities 12-7
■Starting the Database Character Set Scanner
■Creating the Database Character Set Scanner Parameter File
■Getting Command-Line Help for the Database Character Set Scanner
Access Privileges for the Database Character Set Scanner
To use the Database Character Set Scanner, you must have DBA privileges for Oracle
Database.
Installing the Database Character Set Scanner System Tables
Before using the Database Character Set Scanner, you must run the csminst.sql
script to set up the necessary system tables on the database that you plan to scan. The
csminst.sql script needs to be run only once. The script performs the following
tasks to prepare the database for scanning:
■Creates a user named CSMIG
■Assigns the necessary privileges to CSMIG
■Assigns the default tablespace to CSMIG
■Creates the Character Set Scanner system tables under CSMIG
You can modify the default tablespace for CSMIG by editing the csminst.sql script.
Modify the following statement in csminst.sql to assign the preferred tablespace to
CSMIG as follows:
ALTER USER csmig DEFAULT TABLESPACE tablespace_name;
Ensure that there is sufficient storage space available in the assigned tablespace before
scanning the database. The amount of space required depends on the type of scan and
the nature of the data in the database.
On UNIX platforms, run csminst.sql using these commands and SQL statement:
% cd $ORACLE_HOME/rdbms/admin
% sqlplus sys/password as sysdba
SQL> START csminst.sql
Starting the Database Character Set Scanner
You can start the Database Character Set Scanner from the command line by one of
these methods:
■Using the Database Character Set Scanner parameter file
CSSCAN username/password PARFILE=file_name
■Using the command line to specify parameter values. For example:
CSSCAN username/password FULL=y TOCHAR=al32utf8 ARRAY=10240 PROCESS=3
■Using an interactive session
CSSCAN username/password
See Also: "Storage and Performance Considerations in the Database
Character Set Scanner" on page 12-35
Database Character Set Scanner Parameters
12-8 Oracle Database Globalization Support Guide
In an interactive session, the Database Character Set Scanner prompts you for the
values of the following parameters:
FULL/TABLE/USER
TOCHAR
ARRAY
PROCESS
If you want to specify other parameters, then use the Database Character Set
Parameter file or specify the parameter values in the CSSCAN command.
Creating the Database Character Set Scanner Parameter File
The Database Character Set Scanner parameter file enables you to specify Database
Character Set Scanner parameters in a file where they can be easily modified or reused.
Create a parameter file using a text editor.
Use one of the following formats to specify parameters in the Database Character Set
Scanner parameter file:
parameter_name=value
parameter_name=(value1, value2, ...)
You can add comments to the parameter file by preceding them with the pound sign
(#). All characters to the right of the pound sign are ignored.
The following is an example of a parameter file:
USERID=system/manager
USER=HR # scan HR tables
TOCHAR=al32utf8
ARRAY=4096000
PROCESS=2 # use two concurrent scan processes
FEEDBACK=1000
Getting Command-Line Help for the Database Character Set Scanner
The Database Character Set Scanner provides command-line help. Enter the following
command:
CSSCAN HELP=Y
The resulting output shows a summary of the Database Character Set Scanner
parameters.
Database Character Set Scanner Parameters
The following table shows a summary of parameters for the Database Character Set
Scanner. The rest of this section contains detailed descriptions of the parameters.
See Also: "Database Character Set Scanner Parameters" on
page 12-8
Parameter Default Prompt Description
USERID - yes Username/password
FULL Nyes Scan entire database
USER -yes Owner of the tables to be scanned
Database Character Set Scanner Parameters
Character Set Scanner Utilities 12-9
ARRAY
The following formula estimates the number of rows fetched at one time for a given
table:
rows fetched =
(ARRAY value) / [(sum of all the CHAR and VARCHAR2 column sizes) +
(number of CLOB columns * 4000) + (number of VARRAY columns * 4000)]
For example, suppose table A contains two CHAR columns (5 bytes and 10 bytes), two
VARCHAR2 columns (100 bytes and 200 bytes), and one CLOB column. If
TABLE - yes List of tables to scan
EXCLUDE - no List of tables to exclude
TOCHAR - yes New database character set name
FROMCHAR - no Current database character set name
TONCHAR - no New national character set name
FROMNCHAR - no Current national character set name
ARRAY 1024000 yes Size of array fetch buffer
PROCESS 1yes Number of concurrent scan processes
MAXBLOCKS - no The maximum number of blocks that can be in a table without the table
being split
CAPTURE Nno Capture convertible data
COLUMN - no List of columns to scan
QUERY - no Query to apply to restrict output before scan
SUPPRESS - no Maximum number of exceptions logged for each table
FEEDBACK - no Report progress every n rows
BOUNDARIES - no List of column size boundaries for summary report
LASTRPT Nno Generate report of the previous database scan
LOG scan no Base file name for report files
PARFILE - no Parameter file name
PRESERVE Nno Preserve existing scan results
LCSD Nno Enable language and character set detection
LCSDDATA LOSSY no Define the scope of the language and character set detection
HELP Nno Show help screen
Property Description
Default value 1024000
Minimum value 4096
Maximum value Unlimited
Purpose Specifies the size in bytes of the array buffer used to fetch data. The
size of the array buffer determines the number of rows fetched by
the Database Character Set Scanner at any one time.
Parameter Default Prompt Description
Database Character Set Scanner Parameters
12-10 Oracle Database Globalization Support Guide
ARRAY=1024000 (the default), then the number of rows fetched is calculated as
follows:
1024000/[5 + 10 + 100 + 200 + (1*4000) + (0*4000)] = 237.3
The Database Character Set Scanner can fetch 23 rows of data at one time from table A.
If the sum in the denominator exceeds the value of the ARRAY parameter, then the
Database Character Set Scanner fetches only one row at a time. Tables with LONG
columns are fetched only one row at a time.
This parameter affects the duration of a database scan. In general, the larger the size of
the array buffer, the shorter the duration time. Each scan process allocates the specified
size of array buffer.
BOUNDARIES
For example, if you specify a BOUNDARIES value of (10, 100, 1000), then the
application data conversion summary report produces a breakdown of the CHAR data
into the following groups by their column length, CHAR(1..10), CHAR(11..100)
and CHAR(101..1000). The behavior is the same for the VARCHAR2, NCHAR, and
NVARCHAR2 datatypes.
CAPTURE
COLUMN
Property Description
Default value None
Purpose Specifies the list of column boundary sizes that are used for an
application data conversion summary report. This parameter is
used to locate the distribution of the application data for the CHAR,
VARCHAR2, NCHAR, and NVARCHAR2 datatypes.
Property Description
Default value N
Range of values Y or N
Purpose Indicates whether to capture the information on the individual
convertible rows, as well as the default of storing only the exception
rows. Information regarding the convertible rows is written to the
CSM$ERRORS table if the CAPTURE parameter is set to Y. It records the
data that needs to be converted during the conversion to the target
character set. When CAPTURE is set to Y, the data dictionary
CONVERTIBLE data cells are also listed in the database scan individual
exception report scan.err. With CAPTURE set to Y, the amount of time
required to complete the scan can increase and more storage space may
be required.
Property Description
Default value None
Purpose Specifies the names of the columns to be scanned
Database Character Set Scanner Parameters
Character Set Scanner Utilities 12-11
When this parameter is specified, the Database Character Set Scanner scans the
specified columns. You can specify the following when you specify the name of the
column:
■schemaname specifies the names of the user's schema from which to scan the table
■tablename specifies the name of the table from which to scan the column
■columnname specifies the name of the column to be scanned
For example, the following command scans the columns LASTNAME and FIRSTNAME
in the hr sample schema:
CSSCAN system/manager COLUMN=(HR.EMPLOYEES.LASTNAME, HR.EMPLOYEES.FIRSTNAME) ...
EXCLUDE
When this parameter is specified, the Database Character Set Scanner excludes the
specified tables from the scan. You can specify the following when you specify the
name of the table:
■schemaname specifies the name of the user's schema from which to exclude the
table
■tablename specifies the name of the table or tables to be excluded
For example, the following command scans all of the tables that belong to the hr
sample schema except for the employees and departments tables:
CSSCAN system/manager USER=HR EXCLUDE=(HR.EMPLOYEES , HR.DEPARTMENTS) ...
FEEDBACK
For example, if you specify FEEDBACK=1000, then the Database Character Set Scanner
displays a dot for every 1000 rows scanned. The FEEDBACK value applies to all tables
being scanned. It cannot be set for individual tables.
FROMCHAR
Property Description
Default value None
Purpose Specifies the names of the tables to be excluded from the scan
Property Description
Default value None
Minimum value 100
Maximum value 100000
Purpose Specifies that the Database Character Set Scanner should display a
progress meter in the form of a dot for every N number of rows
scanned
Property Description
Default value None
Database Character Set Scanner Parameters
12-12 Oracle Database Globalization Support Guide
Use this parameter to override the default database character set definition for CHAR,
VARCHAR2, LONG, and CLOB data in the database.
FROMNCHAR
Use this parameter to override the default database character set definition for NCHAR,
NVARCHAR2, and NCLOB data in the database.
FULL
HELP
Purpose Specifies the current character set name for CHAR, VARCHAR2,
LONG, and CLOB datatypes in the database. By default, the Database
Character Set Scanner assumes the character set for these datatypes
to be the database character set.
Property Description
Default value The current database character set.
Purpose Specifies the current national database character set name for
NCHAR, NVARCHAR2, and NCLOB datatypes in the database. By
default, the Database Character Set Scanner assumes the character
set for these datatypes to be the database national character set.
Property Description
Default value N
Range of values Y or N
Purpose Indicates whether to perform the full database scan (that is, to scan
the entire database including the data dictionary). Specify FULL=Y
to scan in full database mode.
See Also: "Scan Modes in the Database Character Set Scanner" on
page 12-6 for more information about full database scans
Property Description
Default value N
Range of values Y or N
Purpose Displays a help message with the descriptions of the Database
Character Set Scanner parameters
See Also: Getting Command-Line Help for the Database
Character Set Scanner on page 12-8
Property Description
Database Character Set Scanner Parameters
Character Set Scanner Utilities 12-13
LASTRPT
If LASTRPT=Y is specified, then the Database Character Set Scanner does not scan the
database, but creates the report files using the information left by the previous
database scan session instead.
If LASTRPT=Y is specified, then only the USERID, BOUNDARIES, and LOG parameters
take effect.
LCSD
If LCSD=Y is specified, then the Database Character Set Scanner (CSSCAN) performs
language and character set detection on the data cells categorized by the LCSDDATA
parameter. The accuracy of the detection depends greatly on the size and the quality of
the text being analyzed. The ideal case is literary text of one single language with no
spelling or grammatical errors. Data cells that contain a mixture of languages or
character sets or text such as addresses and names can yield poor results. When
CSSCAN cannot determine the most likely language and character set, it may return up
to three most likely languages and character sets for each cell. In some cases it may
return none. CSSCAN ignores any data cells with less than 10 bytes of data and
returns UNKNOWN for their language and character set.
The language and character set detection is a statistically-based technology, so its
accuracy varies depending on the quality of the input data. The goal is to provide
CSSCAN users with additional information about unknown data inside the database. It
is important for CSSCAN users to review the detection results and the data itself before
migrating the data to another character set.
Note that language and character set detection can affect the performance of the
Database Character Set Scanner, depending on the amount of data that is being
analyzed.
LCSDDATA
Property Description
Default value N
Range of values Y or N
Purpose Indicates whether to regenerate the Database Character Set Scanner
reports based on statistics gathered from the previous database scan
Property Description
Default value N
Range of values Y or N
Purpose Indicates whether to apply language and character set detection
during scanning
See Also: "The Language and Character Set File Scanner" on
page 12-1
Property Description
Default value LOSSY
Database Character Set Scanner Parameters
12-14 Oracle Database Globalization Support Guide
This parameter takes effect only when LCSD=Y is specified. For example, if LCSD=Y
and LCSDDATA=LOSSY, CONVERTIBLE, then the Database Character Set Scanner
tries to detect the character sets and languages of the data cells that are either LOSSY
or CONVERTIBLE. Data that is classified as CHANGELESS and TRUNCATION will not be
processed. Setting LCSDDATA=ALL results in language and character set detection for
all data cells scanned in the current session.
After language and character set detection has been applied to CONVERTIBLE and
TRUNCATION data cells, some data cells may change from their original classification
to LOSSY. This occurs when the character set detection process determines that the
character set of these data cells is not the character set specified in the FROMCHAR
parameter.
LOG
By default, the Database Character Set Scanner generates the three text files,
scan.txt, scan.err, and scan.out in the current directory.
MAXBLOCKS
For example, if the MAXBLOCKS parameter is set to 1000, then any tables that are
greater than 1000 blocks in size are divided into n chunks, where
n=CEIL(table block size/1000).
Dividing large tables into smaller pieces is beneficial only when the number of
processes set with PROCESS is greater than 1. If the MAXBLOCKS parameter is not set,
then the Database Character Set Scanner attempts to split up large tables based on its
own optimization rules.
Range of values LOSSY, TRUNCATION, CONVERTIBLE, CHANGELESS, ALL
Purpose Specifies the scope of the language and character set detection. The
default is to apply the detection to only the LOSSY data cells.
Property Description
Default value scan
Purpose Specifies a base file name for the following Database Character Set
Scanner report files:
■Database Scan Summary Report file, whose extension is .txt
■Individual Exception Report file, whose extension is .err
■Screen log file, whose extension is .out
Property Description
Default value None
Minimum value 1000
Maximum value Unlimited
Purpose Specifies the maximum block size for each table, so that large tables
can be split into smaller chunks for the Database Character Set
Scanner to process
Property Description
Database Character Set Scanner Parameters
Character Set Scanner Utilities 12-15
PARFILE
PRESERVE
If PRESERVE=Y is specified, then the Database Character Set Scanner preserves all of
the statistics from the previous scan. It adds (if PRESERVE=Y) or overwrites (if
PRESERVE=N) the new statistics for the tables being scanned in the current scan
request.
PROCESS
QUERY
The value of the query parameter is a string that contains a WHERE clause for a SELECT
statement that will be applied to all tables and columns listed in the TABLE and
COLUMN parameters.
Only one query clause is allowed per scan session. The QUERY parameter is only
applicable when performing table or column scans. The parameter will be ignored
when performing a Full database or a User scan. QUERY can be applied to multiple
Property Description
Default value None
Purpose Specifies the name for a file that contains a list of Database
Character Set Scanner parameters
See Also: "Starting the Database Character Set Scanner" on
page 12-7
Property Description
Default value N
Range of values Y or N
Purpose Indicates whether to preserve the statistics gathered from the
previous scan session
Property Description
Default value 1
Minimum value 1
Maximum value 32
Purpose Specifies the number of concurrent scan processes to utilize for the
database scan
Property Description
Default value None
Purpose Applies a filter to restrict the data to be scanned by specifying a
clause for a SELECT statement, which is applied to all tables and
columns in the scanner session
Database Character Set Scanner Parameters
12-16 Oracle Database Globalization Support Guide
tables and columns scans, however, the identical WHERE clause will be appended to all
specified tables and columns.
For example, the following command scans the employess who were hired within the
last 30 days:
CSSCAN system/manager TABLE=HR.EMPLOYEES QUERY= 'hire_date > SYSDATE - 180' ...
Note that the WHERE clause is not required inside the QUERY parameter. CSSCAN will
automatically remove the WHERE clause if it is found to be the first five characters in
the QUERY parameter.
SUPPRESS
The Database Character Set Scanner inserts information into the CSM$ERRORS table
when an exception is found in a data cell. The table grows depending on the number
of exceptions reported.
This parameter is used to suppress the logging of individual exception information
after a specified number of exceptions are inserted for each table. For example, if
SUPPRESS is set to 100, then the Database Character Set Scanner records a maximum
of 100 exception records for each table.
TABLE
You can specify the following when you specify the name of the table:
■schemaname specifies the name of the user's schema from which to scan the table
■tablename specifies the name of the table or tables to be scanned
For example, the following command scans the employees and departments tables
in the HR sample schema:
CSSCAN system/manager TABLE=(HR.EMPLOYEES, HR.DEPARTMENTS)
TOCHAR
Property Description
Default value Unset (results in unlimited number of rows)
Minimum value 0
Maximum value Unlimited
Purpose Specifies the maximum number of data exceptions being logged for
each table
See Also: "Storage Considerations for the Database Character Set
Scanner" on page 12-35
Property Description
Default value None
Purpose Specifies the names of the tables to scan
Property Description
Default value None
Database Character Set Scanner Sessions: Examples
Character Set Scanner Utilities 12-17
TONCHAR
If you do not specify a value for TONCHAR, then the Database Character Set Scanner
does not scan NCHAR, NVARCHAR2, and NCLOB data.
USER
If the USER parameter is specified, then the Database Character Set Scanner scans all
tables belonging to the specified owner. For example, the following statement scans all
tables belonging to HR:
CSSCAN system/manager USER=hr ...
USERID
The following formats are all valid:
username/password
username/password@connect_string
username
username@connect_string
Database Character Set Scanner Sessions: Examples
The following examples show you how to use the command-line and parameter-file
methods for the Full Database, User, Single Table, and Column scan modes.
Purpose Specifies a target database character set name for the CHAR,
VARCHAR2, LONG, and CLOB data
Property Description
Default value None
Purpose Specifies a target database character set name for the NCHAR,
NVARCHAR2, and NCLOB data
Property Description
Default value None
Purpose Specifies the owner of the tables to be scanned
Property Description
Default value None
Purpose Specifies the username and password (and optional connect string)
of the user who scans the database. If you omit the password, then
the Database Character Set Scanner prompts you for it
Property Description
Database Character Set Scanner Sessions: Examples
12-18 Oracle Database Globalization Support Guide
Full Database Scan Examples
The following examples show how to scan the full database to see the effects of
migrating it to AL32UTF8. These examples assume that the current database character
set is WE8ISO8859P1.
Example 12–6 Database Scan Using the Parameter-File Method
% csscan system/manager parfile=param.txt
The param.txt file contains the following information:
full=y
tochar=al32utf8
array=4096000
process=4
Example 12–7 Database Scan Using the Command-Line Method
% csscan system/manager full=y tochar=al32utf8 array=4096000 process=4
Database Character Set Scanner Messages
The scan.out file shows which tables were scanned. The default file name for the
report can be changed by using the LOG parameter.
Database Character Set Scanner vx.x : Release xx.x.x.x.x - Production
Copyright (c) 1982, 200x, Oracle. All rights reserved.
Connected to:
Oracle Database xxx Enterprise Edition Release xx.x.x.x.x - Production
With the Partitioning and Data Mining options
Enumerating tables to scan...
. process 1 scanning SYS.SOURCE$[AAAABHAABAAAAJqAAA]
. process 2 scanning SYS.TAB$[AAAAACAABAAAAA0AAA]
. process 2 scanning SYS.CLU$[AAAAACAABAAAAA0AAA]
. process 2 scanning SYS.ICOL$[AAAAACAABAAAAA0AAA]
. process 2 scanning SYS.COL$[AAAAACAABAAAAA0AAA]
. process 1 scanning SYS.IND$[AAAAACAABAAAAA0AAA]
. process 1 scanning SYS.TYPE_MISC$[AAAAACAABAAAAA0AAA]
. process 1 scanning SYS.LOB$[AAAAACAABAAAAA0AAA]
.
.
.
. process 1 scanning IX.AQ$_ORDERS_QUEUETABLE_G
. process 2 scanning IX.AQ$_ORDERS_QUEUETABLE_I
Creating Database Scan Summary Report...
Creating Individual Exception Report...
Scanner terminated successfully.
See Also: "LOG" on page 12-14
Database Character Set Scanner Sessions: Examples
Character Set Scanner Utilities 12-19
User Scan Examples
The following examples show how to scan the user tables to see the effects of
migrating them to AL32UTF8. These examples assume that the current database
character set is US7ASCII, but the actual data stored is in Western European
WE8MSWIN1252 encoding.
Example 12–8 User Scan with Parameter-File Method
% csscan system/manager parfile=param.txt
The param.txt file contains the following information:
user=hr
fromchar=we8mswin1252
tochar=al32utf8
array=4096000
process=1
Example 12–9 User Scan with Command-Line Method
% csscan system/manager user=hr fromchar=we8mswin1252
tochar=al32utf8 array=4096000 process=1
Database Character Set Scanner Messages
The scan.out file shows which tables were scanned.
Database Character Set Scanner vx.x : Release xx.x.x.x.x - Production
Copyright (c) 1982, 200x, Oracle. All rights reserved.
Connected to:
Oracle Database xxx Enterprise Edition Release xx.x.x.x.x - Production
With the Partitioning and Data Mining options
Copyright (c) 1983, 200x Oracle. All rights reserved.
Enumerating tables to scan...
. process 1 scanning HR.JOBS
. process 1 scanning HR.DEPARTMENTS
. process 1 scanning HR.JOB_HISTORY
. process 1 scanning HR.EMPLOYEES
Creating Database Scan Summary Report...
Creating Individual Exception Report...
Scanner terminated successfully.
Single Table Scan Examples
The following examples show how to scan a single table to see the effects of migrating
it to WE8MSWIN1252. These examples assume that the current database character set
is in US7ASCII. Language and character set detection is performed on the LOSSY data
cells.
Example 12–10 Single Table Scan with Parameter-File Method
% csscan system/manager parfile=param.txt
Database Character Set Scanner Sessions: Examples
12-20 Oracle Database Globalization Support Guide
The param.txt file contains the following information:
table=hr.employees
tochar=we8mswin1252
array=4096000
process=1
suppress=100
lcsd=y
Example 12–11 Single Table Scan with Command-Line Method
% csscan system/manager table=hr.employees tochar=we8mswin1252 array=4096000
process=1 supress=100 lcsd=y
Database Character Set Scanner Messages
The scan.out file shows which tables were scanned.
Database Character Set Scanner vx.x : Release xx.x.x.x.x - Production
Copyright (c) 1982, 200x, Oracle. All rights reserved.
Connected to:
Oracle Database xxx Enterprise Edition Release xx.x.x.x.x - Production
With the Partitioning and Data Mining options
Copyright (c) 1983, 200x Oracle. All rights reserved.
. process 1 scanning HR.EMPLOYEES
Creating Database Scan Summary Report...
Creating Individual Exception Report...
Scanner terminated successfully.
The following example shows how to scan a single table to see the effect of migrating
it to WE8MSWIN1252. Before scanning, a query is run against the table to limit the
rows that will be scanned. This example assumes the current database character set is
in US7ASCII. Language and character set detection is performed on the LOSSY data
cells.
Example 12–12 Single Table Scan with Parameter-File Method, Showing the Effect of
Migrating to WE8MSWIN1252
% csscan system/manager parfile=param.txt
The param.txt file contains the following information:
table=hr.employees
query='hire_date > SYSDATE - 180'
tochar=we8mswin1252
array=4096000
process=1
suppress=100
lcsd=y
Example 12–13 Single Table Scan with Command-File Method, Showing the Effect of
Migrating to WE8MSWIN1252
% csscan system/manager table=hr.employees query='hire_date > SYSDATE - 180'
Database Character Set Scanner Sessions: Examples
Character Set Scanner Utilities 12-21
tochar=we8mswin1252 array=4096000 process=1 supress=100 lcsd=y
Database Character Set Scanner Messages
The scan.out file shows which tables were scanned.
Database Character Set Scanner vx.x : Release xx.x.x.x.x - Production
Copyright (c) 1982, 200x, Oracle. All rights reserved.
Connected to:
Oracle Database xxx Enterprise Edition Release xx.x.x.x.x - Production
With the Partitioning and Data Mining options
Copyright (c) 1983, 200x Oracle. All rights reserved.
. process 1 scanning HR.EMPLOYEES
Creating Database Scan Summary Report...
Creating Individual Exception Report...
Scanner terminated successfully.
Column Scan Examples
The following example shows how to scan columns within a table to see the effects of
migrating it to WE8MSWIN1252. This example assumes the current database character
set is in US7ASCII. Language and character set detection is performed on the LOSSY
data cells.
Example 12–14 Column Scan with Parameter-File Method
% csscan system/manager parfile=param.txt
The param.txt file contains the following information:
column=(hr.employees.lastname, hr.employees.firstname)
tochar=we8mswin1252
array=4096000
process=1
suppress=100
lcsd=y
Example 12–15 Column Scan with Command-Line Method
% csscan system/manager column=(hr.employees.lastname, hr.employees.firstname)
tochar=we8mswin1252 array=4096000 process=1 supress=100 lcsd=y
Database Character Set Scanner Messages
The scan.out file shows which tables were scanned.
Database Character Set Scanner vx.x : Release xx.x.x.x.x - Production
Copyright (c) 1982, 200x, Oracle. All rights reserved.
Connected to:
Oracle Database xxx Enterprise Edition Release xx.x.x.x.x - Production
With the Partitioning and Data Mining options
Copyright (c) 1983, 200x Oracle. All rights reserved.
Database Character Set Scanner Reports
12-22 Oracle Database Globalization Support Guide
. process 1 scanning HR.EMPLOYEES
Creating Database Scan Summary Report...
Creating Individual Exception Report...
Scanner terminated successfully.
Database Character Set Scanner Reports
The Database Character Set Scanner generates two reports for each scan:
■Database Scan Summary Report
■Database Scan Individual Exception Report
The Database Scan Summary Report is found in the scan.txt file. The Database Scan
Individual Exception Report is found in the scan.err file.
The default file names for the reports can be changed by using the LOG parameter.
Database Scan Summary Report
The scan.txt file contains the Database Scan Summary Report. The following output
is an example of the report header. This section contains the time when each process of
the scan was performed.
Database Scan Summary Report
Time Started : 200x-12-16 20:35:56
Time Completed: 200x-12-16 20:37:31
Process ID Time Started Time Completed
---------- -------------------- --------------------
1 200x-12-16 20:36:07 2002-12-16 20:37:30
2 200x-12-16 20:36:07 2002-12-16 20:37:30
---------- -------------------- --------------------
The report consists of the following sections:
■Database Size
■Database Scan Parameters
■Scan Summary
■Data Dictionary Conversion Summary
■Application Data Conversion Summary
■Application Data Conversion Summary Per Column Size Boundary
■Distribution of Convertible Data Per Table
■Distribution of Convertible Data Per Column
■Indexes To Be Rebuilt
■Truncation Due To Character Semantics
The information available for each section depends on the type of scan and the
parameters you select.
See Also: "LOG" on page 12-14
Database Character Set Scanner Reports
Character Set Scanner Utilities 12-23
Database Size
This section reports on the current database size as well as identifying the amount of
potential data expansion after the character set migration.
The following output is an example.
Tablespace Used Free Total Expansion
------------------------- --------------- --------------- --------------- ---------------
SYSTEM 206.63M 143.38M 350.00M 588.00K
SYSAUX 8.25M 131.75M 140.00M .00K
------------------------- --------------- --------------- --------------- ---------------
Total 214.88M 275.13M 490.00M 588.00K
The size of the largest CLOB is 57370 bytes
Database Scan Parameters
This section describes the parameters selected and the type of scan you chose. The
following output is an example.
Parameter Value
------------------------------ ------------------------------------------------
CSSCAN Version v2.1
Instance Name rdbms06
Database Version 10.2.0.0.0
Scan type Full database
Scan CHAR data? YES
Database character set WE8ISO8859P1
FROMCHAR WE8ISO8859P1
TOCHAR AL32UTF8
Scan NCHAR data? NO
Array fetch buffer size 1024000
Number of processes 2
Capture convertible data? NO
Charset Language Detections Yes
Charset Language Parameter LOSSY
------------------------------ ------------------------------------------------
Scan Summary
This section indicates the feasibility of the database character set migration. There are
two basic criteria that determine the feasibility of the character set migration of the
database. One is the condition of the data dictionary and the other is the condition of
the application data.
The Scan Summary section consists of two status lines: one line reports on the data
dictionary, and the other line reports on the application data.
The following is sample output from the Scan Summary:
All character type data in the data dictionary are convertible to the new character set
Some character type application data are not convertible to the new character set
Table 12–1 shows the types of status that can be reported for the data dictionary and
application data.
See Also: "Database Character Set Scanner CSALTER Script" on
page 12-37
Database Character Set Scanner Reports
12-24 Oracle Database Globalization Support Guide
When all data remains the same in the new character set, it means that the encoding
values of the original character set are identical in the target character set. For example,
ASCII data is stored using the same binary values in both WE8ISO8859P1 and AL32
UTF8. In this case, the database character set can be migrated using the CSALTER
script.
If all the data is convertible to the new character set, then the data can be safely
migrated using the Export and Import utilities. However, the migrated data will have
different encoding values in the target character set.
Data Dictionary Conversion Summary
This section contains the statistics about the conversion of the data in the data
dictionary. The numbers of data cells with each type of status are reported by
datatype. To achieve a comprehensive data dictionary conversion summary, you need
to use a full database scan.
Table 12–2 describes the possible types of status of a data cell.
In order to provide more information on how to convert data in the data dictionary,
the Data Dictionary Conversion Summary report has been divided into two parts:
Data Dictionary Tables, and XML CSX Dictionary Tables. Compact binary XML (CSX)
is a new format for XML documents in XML DB in Oracle Database 11g Release 1
(11.1). When you insert an XML document into a CSX column, the database saves CSX
data into a BLOB column in the application data part. Simultaneously, the database
saves the data into the tables of the XDB user, which belong to data dictionary. In the
data dictionary, these tables are called as XML CSX Dictionary Tables.
Table 12–1 Possible Status of the Data Dictionary and Application Data
Data Dictionary Status Application Data Status
All character-type data in the data dictionary remains
the same in the new character set. All character-type application data remains the same in
the new character set.
All character-type data in the data dictionary is
convertible to the new character set. All character-type application data is convertible to the
new character set.
Some character-type data in the data dictionary is not
convertible to the new character set. Some character-type application data is not convertible to
the new character set.
See Also:
■"Database Scan Individual Exception Report" on page 12-31 for
more information about non-convertible data
■"Migrating a Character Set Using the CSALTER Script" on
page 11-6
■"Migrating Character Data Using a Full Export and Import" on
page 11-6
Table 12–2 Possible Status of Data
Status Description
Changeless Data remains the same in the new character set
Convertible Data can be successfully converted to the new character set
Truncation Data will be truncated if conversion takes place
Lossy Character data will be lost if conversion takes place
Database Character Set Scanner Reports
Character Set Scanner Utilities 12-25
Similarly, the tables for "Distribution of Convertible, Truncated and Lossy Data by
Table" and "Distribution of Convertible, Truncated and Lossy Data by Column" have
been organized into three parts, respectively: Data Dictionary Tables, XML CSX
Dictionary Tables, and Application Data.
The following output is an example of the expanded Data Dictionary Conversion
Summary report.
Database Scan Summary Report
Time Started : 2006-08-15 01:13:24
Time Completed: 2006-08-15 01:16:32
Process ID Time Started Time Completed
---------- -------------------- --------------------
1 2006-08-15 01:13:28 2006-08-15 01:16:30
---------- -------------------- --------------------
[Database Size]
Tablespace Used Free Total Expansion
------------------------- --------------- --------------- --------------- ---------------
SYSTEM 542.77M 9.82M 552.59M 1.41M
SYSAUX 80.00M .00K 80.00M 574.00K
TEMP .00K .00K .00K .00K
XDB_RESINFO 51.81M 48.19M 100.00M 18.00K
XDB_TEMP .00K .00K .00K .00K
------------------------- --------------- --------------- --------------- ---------------
Total 674.59M 58.01M 732.59M 1.98M
The size of the largest CLOB is 61115 bytes
[Database Scan Parameters]
Parameter Value
------------------------------ ------------------------------------------------
CSSCAN Version v2.1
Instance Name cm2
Database Version 11.1.0.0.0
Scan type Full database
Scan CHAR data? YES
Database character set WE8ISO8859P1
FROMCHAR we8iso8859p1
TOCHAR utf8
Scan NCHAR data? YES
NCHAR character set AL16UTF16
FROMNCHAR al16utf16
TONCHAR utf8
Array fetch buffer size 102400
Number of processes 1
Capture convertible data? NO
------------------------------ ------------------------------------------------
[Scan Summary]
All character type data in the data dictionary are convertible to the new character set
All character type application data are convertible to the new character set
[Data Dictionary Conversion Summary]
Data Dictionary Tables:
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 3,294,477 0 0 0
CHAR 1,941 0 0 0
Database Character Set Scanner Reports
12-26 Oracle Database Globalization Support Guide
LONG 133,551 0 0 0
CLOB 21,633 841 0 0
NVARCHAR2 0 0 0 0
NCHAR 0 0 0 0
NCLOB 0 0 0 0
VARRAY 26,965 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 3,478,567 841 0 0
Total in percentage 99.976% 0.024% 0.000% 0.000%
The data dictionary can be safely migrated using the CSALTER script
XML CSX Dictionary Tables:
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 173 8 0 0
CHAR 0 0 0 0
LONG 0 0 0 0
CLOB 0 0 0 0
NVARCHAR2 0 0 0 0
NCHAR 0 0 0 0
NCLOB 0 0 0 0
VARRAY 0 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 173 8 0 0
Total in percentage 95.580% 4.420% 0.000% 0.000%
[Application Data Conversion Summary]
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 36,011 0 0 0
CHAR 5,533 0 0 0
LONG 0 0 0 0
CLOB 27 26 0 0
NVARCHAR2 0 17,280 0 0
NCHAR 0 0 0 0
NCLOB 4 0 0 0
VARRAY 319 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 41,894 17,306 0 0
Total in percentage 70.767% 29.233% 0.000% 0.000%
[Distribution of Convertible, Truncated and Lossy Data by Table]
Data Dictionary Tables:
USER.TABLE Convertible Truncation Lossy
-------------------------------------------------- ---------------- ---------------- ----------------
SYS.EXTERNAL_TAB$ 1 0 0
SYS.METASTYLESHEET 145 0 0
SYS.RULE$ 1 0 0
SYS.SCHEDULER$_EVENT_LOG 26 0 0
SYS.WRH$_SQLTEXT 239 0 0
SYS.WRH$_SQL_PLAN 217 0 0
SYS.WRI$_ADV_DIRECTIVE_META 5 0 0
SYS.WRI$_ADV_OBJECTS 1 0 0
SYS.WRI$_DBU_FEATURE_METADATA 94 0 0
SYS.WRI$_DBU_FEATURE_USAGE 3 0 0
SYS.WRI$_DBU_HWM_METADATA 17 0 0
SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY 71 0 0
SYS.WRI$_REPT_FILES 4 0 0
XDB.XDB$RESCONFIG 9 0 0
XDB.XS$PRINCIPALS 1 0 0
XDB.XS$SECURITYCLASS 7 0 0
Database Character Set Scanner Reports
Character Set Scanner Utilities 12-27
-------------------------------------------------- ---------------- ---------------- ----------------
XML CSX Dictionary Tables:
USER.TABLE Convertible Truncation Lossy
-------------------------------------------------- ---------------- ---------------- ----------------
XDB.X$QN0S0VE2C21FAJ8E0G5PHDLAO3BO 8 0 0
-------------------------------------------------- ---------------- ---------------- ----------------
Application Data:
USER.TABLE Convertible Truncation Lossy
-------------------------------------------------- ---------------- ---------------- ----------------
OE.PRODUCT_DESCRIPTIONS 17,280 0 0
OE.WAREHOUSES 4 0 0
PM.ONLINE_MEDIA 14 0 0
PM.PRINT_MEDIA 8 0 0
-------------------------------------------------- ---------------- ---------------- ----------------
[Distribution of Convertible, Truncated and Lossy Data by Column]
Data Dictionary Tables:
USER.TABLE|COLUMN Convertible Truncation Lossy
-------------------------------------------------- ---------------- ---------------- ----------------
SYS.EXTERNAL_TAB$|PARAM_CLOB 1 0 0
SYS.METASTYLESHEET|STYLESHEET 145 0 0
SYS.RULE$|CONDITION 1 0 0
SYS.SCHEDULER$_EVENT_LOG|ADDITIONAL_INFO 26 0 0
SYS.WRH$_SQLTEXT|SQL_TEXT 239 0 0
SYS.WRH$_SQL_PLAN|OTHER_XML 217 0 0
SYS.WRI$_ADV_DIRECTIVE_META|DATA 5 0 0
SYS.WRI$_ADV_OBJECTS|ATTR4 1 0 0
SYS.WRI$_DBU_FEATURE_METADATA|INST_CHK_LOGIC 11 0 0
SYS.WRI$_DBU_FEATURE_METADATA|USG_DET_LOGIC 83 0 0
SYS.WRI$_DBU_FEATURE_USAGE|FEATURE_INFO 3 0 0
SYS.WRI$_DBU_HWM_METADATA|LOGIC 17 0 0
SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY|EXPRESSION 71 0 0
SYS.WRI$_REPT_FILES|SYS_NC00005$ 4 0 0
XDB.XDB$RESCONFIG|XMLDATA 9 0 0
XDB.XS$PRINCIPALS|XMLDATA 1 0 0
XDB.XS$SECURITYCLASS|XMLDATA 7 0 0
-------------------------------------------------- ---------------- ---------------- ----------------
XML CSX Dictionary Tables:
USER.TABLE|COLUMN Convertible Truncation Lossy
-------------------------------------------------- ---------------- ---------------- ----------------
XDB.X$QN0S0VE2C21FAJ8E0G5PHDLAO3BO|LOCALNAME 8 0 0
-------------------------------------------------- ---------------- ---------------- ----------------
Application Data:
USER.TABLE|COLUMN Convertible Truncation Lossy
-------------------------------------------------- ---------------- ---------------- ----------------
OE.PRODUCT_DESCRIPTIONS|TRANSLATED_DESCRIPTION 8,640 0 0
OE.PRODUCT_DESCRIPTIONS|TRANSLATED_NAME 8,640 0 0
OE.WAREHOUSES|SYS_NC00003$ 4 0 0
PM.ONLINE_MEDIA|SYS_NC00042$ 7 0 0
PM.ONLINE_MEDIA|SYS_NC00062$ 7 0 0
PM.PRINT_MEDIA|AD_FINALTEXT 4 0 0
PM.PRINT_MEDIA|AD_SOURCETEXT 4 0 0
-------------------------------------------------- ---------------- ---------------- ----------------
Database Character Set Scanner Reports
12-28 Oracle Database Globalization Support Guide
[Indexes to be Rebuilt]
USER.INDEX on USER.TABLE(COLUMN)
-----------------------------------------------------------------------------------------
SYS.I_WRI$_OPTSTAT_HH_ST on SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY(SYS_NC00024$)
SYS.I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST on SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY(SYS_NC00024$)
SYS.I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST on SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY(OBJ#)
SYS.I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST on SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY(INTCOL#)
SYS.I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST on SYS.WRI$_OPTSTAT_HISTHEAD_HISTORY(COLNAME)
OE.PROD_NAME_IX on OE.PRODUCT_DESCRIPTIONS(TRANSLATED_NAME)
XDB.X$QQ0S0VE2C21FAJ8E0G5PHDLAO3BO on XDB.X$QN0S0VE2C21FAJ8E0G5PHDLAO3BO(NMSPCID)
XDB.X$QQ0S0VE2C21FAJ8E0G5PHDLAO3BO on XDB.X$QN0S0VE2C21FAJ8E0G5PHDLAO3BO(LOCALNAME)
XDB.X$QQ0S0VE2C21FAJ8E0G5PHDLAO3BO on XDB.X$QN0S0VE2C21FAJ8E0G5PHDLAO3BO(FLAGS)
-----------------------------------------------------------------------------------------
The following output is an example of the Data Dictionary Conversion Summary
report in previous releases.
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 1,214,557 0 0 0
CHAR 967 0 0 0
LONG 88,657 0 0 0
CLOB 138 530 0 0
VARRAY 18 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 1,304,337 530 0 0
Total in percentage 99.959% 0.041% 0.000% 0.000%
The data dictionary can be safely migrated using the CSALTER script.
If the numbers of data cells recorded in the Convertible, Truncation, and Lossy
columns are zero in the data dictionary tables and the XML CSX dictionary tables, then
no data conversion is required to migrate the data dictionary from the FROMCHAR
character set to the TOCHAR character set.
If the numbers in the Truncation and Lossy columns are zero and some numbers in
the Convertible columns are not zero in both data dictionary tables and XML CSX
dictionary tables, then all data in the data dictionary is convertible to the new
character set. However, it is dangerous to convert the data in the data dictionary
without understanding their impact on the database. All convertible cells in the XML
CSX dictionary tables can be safely converted, so they are output explicitly out of the
data dictionary tables. The CSALTER script can convert some of the convertible cells in
the data dictionary. The message that follows the conversion summary table indicates
whether this conversion can be supported by the CSALTER script.
If the numbers in the Lossy column are not zero in the data dictionary tables or XML
CSX dictionary tables, then there is data in the data dictionary that is not convertible.
Therefore, it is not feasible to migrate the current database to the new character
because the export and import processes cannot convert the data into the new
character set. For example, you might have a table name with invalid characters or a
PL/SQL procedure with a comment line that includes data that cannot be mapped to
the new character set. These changes to schema objects must be corrected manually
before migration to a new character set.
If the numbers in the Truncation column are not zero in the data dictionary tables or
XML CSX dictionary tables, then the export and import process will truncate the data.
Database Character Set Scanner Reports
Character Set Scanner Utilities 12-29
Application Data Conversion Summary
This section contains the statistics on conversion summary of the application data. The
numbers of data cells with each type of status are reported by datatype. Table 12–2
describes the types of status that can be reported.
The following output is an example.
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 37,757 3 0 0
CHAR 6,404 0 0 0
LONG 4 0 0 0
CLOB 23 20 0 1
VARRAY 319 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 44,507 23 0 1
Total in percentage 99.946% 0.051% 0% 0.002%
Application Data Conversion Summary Per Column Size Boundary
This section contains the conversion summary of the CHAR and VARCHAR2 application
data. The number of data cells with each type of status are reported by column size
boundaries specified by the BOUNDARIES parameter. Table 12–2 describes the possible
types of status. This information is available only when the BOUNDARIES parameter is
specified. The following output is an example.
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2(1..30) 28,702 2 0 0
VARCHAR2(31..4000) 9,055 1 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
CHAR(1..30) 6,404 0 0 0
CHAR(31..4000) 0 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 44,161 3 0 0
Distribution of Convertible Data Per Table
This section shows how Convertible, Truncation, and Lossy data is distributed
within the database. The statistics are reported by table. If the list contains only a few
rows, then the Convertible data is localized. If the list contains many rows, then the
Convertible data occurs throughout the database. The following output is an
example.
USER.TABLE Convertible Truncation Lossy
---------------------------- ---------------- ---------------- ----------------
HR.EMPLOYEES 1 0 0
OE.CUSTOMERS 2 0 0
PM.ONLINE_MEDIA 13 0 0
PM.PRINT_MEDIA 7 0 1
SYS.EXTERNAL_TAB$ 1 0 0
SYS.METASTYLESHEET 80 0 0
---------------------------- ---------------- ---------------- ----------------
See Also:
■"Database Character Set Scanner CSALTER Script" on
page 12-37
■"How to Handle Convertible or Lossy Data in the Data
Dictionary" on page 12-33
Database Character Set Scanner Reports
12-30 Oracle Database Globalization Support Guide
Distribution of Convertible Data Per Column
This section shows how Convertible, Truncation, and Lossy data is distributed
within the database. The statistics are reported by column. The following output is an
example.
USER.TABLE|COLUMN Convertible Truncation Lossy
------------------------------------- ---------------- ---------------- ----------------
HR.EMPLOYEES|FIRST_NAME 1 0 0
OE.CUSTOMERS|CUST_EMAIL 1 0 0
OE.CUSTOMERS|CUST_FIRST_NAME 1 0 0
PM.ONLINE_MEDIA|SYS_NC00042$ 6 0 0
PM.ONLINE_MEDIA|SYS_NC00062$ 7 0 0
PM.PRINT_MEDIA|AD_FINALTEXT 3 0 1
PM.PRINT_MEDIA|AD_SOURCETEXT 4 0 0
SYS.EXTERNAL_TAB$|PARAM_CLOB 1 0 0
SYS.METASTYLESHEET|STYLESHEET 80 0 0
------------------------------------- ---------------- ---------------- ----------------
Indexes To Be Rebuilt
This generates a list of all the indexes that are affected by the database character set
migration. These can be rebuilt after the data has been imported. The following output
is an example.
USER.INDEX on USER.TABLE(COLUMN)
--------------------------------------------------------------------------------------
HR.EMP_NAME_IX on HR.EMPLOYEES(FIRST_NAME)
HR.EMP_NAME_IX on HR.EMPLOYEES(LAST_NAME)
OE.CUST_EMAIL_IX on OE.CUSTOMERS(CUST_EMAIL)
--------------------------------------------------------------------------------------
Truncation Due To Character Semantics
This section applies only to columns that are defined using character semantics. The
Truncation Due to Character Semantics section identifies the number of data cells that
would be truncated if they were converted to the target character set (for example, by
the SQL CONVERT function or another inline conversion process) before the database
character set is updated with the CSALTER script. If the data conversion occurs after
the database character set is changed, then this section can be ignored.
For example, a VARCHAR2(5 char) column in a WE8MSWIN1252 database can store
up to 5 characters, using 5 bytes. When these characters are migrated to AL32UTF8,
the same 5 characters can expand to as much as 20 bytes in length. Because the
physical byte limits allocated for the column are determined by the current database
character set, this column must be manually expanded to 20 bytes before the data can
be converted in the target character set. Alternatively, you can apply the character set
conversion to this column after the database character set has been changed. Then the
same VARCHAR2(5 char) definition will automatically allocate 20 bytes, and no
special handling is required.
The following output is an example of the Truncation Due To Character Semantics
section of the report.
USER.TABLE|COLUMN Truncation
-------------------------------------------------- ----------------
HR.EMPLOYEES|FIRST_NAME 1
Character Set Detection Result
This section appears when the language and character set detection is turned on by the
LCSD parameter. It displays a list of character sets detected by the Database Character
Database Character Set Scanner Reports
Character Set Scanner Utilities 12-31
Set Scanner. The character sets are ordered by occurrence. NUMBER refers to the
number of data cells.
The following output is an example of the Character Set Detection Result section.
CHARACTER SET NUMBER PERCENTAGE
------------------------------ ---------------- ----------------
WE8MSWIN1252 38 97.436%
UNKNOWN 1 2.564%
------------------------------ ---------------- ----------------
Language Detection Result
This section appears when the language and character set detection is turned on by the
LCSD parameter. It displays a list of the languages detected by the Database Character
Set Scanner. The languages are ordered by occurrence.
The following output is an example of the Language Detection Result Section.
LANGUAGE NUMBER PERCENTAGE
------------------------------ ---------------- ----------------
ENGLISH 36 92.308%
FRENCH 2 5.128%
UNKNOWN 1 2.564%
------------------------------ ---------------- ----------------
Database Scan Individual Exception Report
The scan.err file contains the Individual Exception Report. It consists of the following
summaries:
■Database Scan Parameters
■Data Dictionary Individual Exceptions
■Application Data Individual Exceptions
Database Scan Parameters
This section describes the parameters and the type of scan chosen. The following
output is an example.
Parameter Value
------------------------------ ------------------------------------------------
CSSCAN Version v2.1
Instance Name rdbms06
Database Version 10.2.0.0.0
Scan type Full database
Scan CHAR data? YES
Database character set WE8ISO8859P1
FROMCHAR WE8ISO8859P1
TOCHAR AL32UTF8
Scan NCHAR data? NO
Array fetch buffer size 1024000
Number of processes 2
Capture convertible data? NO
Charset Language Detection Yes
Charset Language Parameter LOSSY
------------------------------ ------------------------------------------------
Database Character Set Scanner Reports
12-32 Oracle Database Globalization Support Guide
Data Dictionary Individual Exceptions
This section reports on whether data dictionary data is convertible or has exceptions.
There are two types of exceptions:
■exceed column size
■lossy conversion
The following output is an example for a data dictionary that contains convertible
data.
User : SYS
Table : OBJ$
Column: NAME
Type : VARCHAR2(30)
Number of Exceptions : 0
Max Post Conversion Data Size: 30
ROWID Exception Type Size Cell Data(first 30 bytes)
------------------ ------------------ ----- ------------------------------
AAAAASAABAAAikLAAQ convertible Aufträge
------------------ ------------------ ----- ------------------------------
Application Data Individual Exceptions
This report identifies the data with exceptions so that this data can be modified if
necessary.
There are two types of exceptions:
■exceed column size
The column size should be extended if the maximum column width has been
surpassed. Otherwise, data truncation occurs.
■lossy conversion
The data must be corrected before migrating to the new character set. Otherwise
the invalid characters are converted to a replacement character. Replacement
characters are usually specified as ? or ¿ or as a character that is linguistically
similar to the source character.
The following example shows an individual exception report that illustrates some
possible problems when changing the database character set from WE8ISO8859P1 to
AL32UTF8.
User: USER1
Table: TEST
Column: NAME
Type: VARCHAR2(10)
Number of Exceptions: 2
Max Post Conversion Data Size: 11
ROWID Exception Type Size Cell Data(first 30 bytes)
------------------ ------------------ ----- ------------------------------
AAAA2fAAFAABJwQAAg exceed column size 11 Ährenfeldt
See Also:
■"Application Data Individual Exceptions" on page 12-32 for
more information about exceptions
■"How to Handle Convertible or Lossy Data in the Data
Dictionary" on page 12-33
How to Handle Convertible or Lossy Data in the Data Dictionary
Character Set Scanner Utilities 12-33
AAAA2fAAFAABJwQAAu lossy conversion órâclë8™
AAAA2fAAFAABJwQAAu exceed column size 11 órâclë8™
------------------ ------------------ ----- ------------------------------
The values Ährenfeldt and órâclë8™ exceed the column size (10 bytes) because
each of the characters Ä, ó, â, and ë occupies one byte in WE8ISO8859P1 but two bytes
in AL32UTF8. The value órâclë8™ has lossy conversion to AL32UTF8 because the
trademark sign ™ (code 153) is not a valid WE8ISO8859P1 character. It is a
WE8MSWIN1252 character, which is a superset of WE8ISO8859P1.
You can view the data that has an exception by issuing a SELECT statement:
SELECT name FROM user1.test WHERE ROWID='AAAA2fAAFAABJwQAAu';
You can modify the data that has the exception by issuing an UPDATE statement:
UPDATE user1.test SET name = 'Oracle8 TM'
WHERE ROWID='AAAA2fAAFAABJwQAAu';
If the language and character set detection option is enabled, then CSSCAN attempts to
provide the most probable languages and character sets for the data cells specified by
the LCSDDATA parameter.
The following example shows an individual exception report that illustrates language
and character set detection results for lossy data cells when changing the database
character set from US7ASCII to AL32UTF8.
User: USER2
Table: TEST
Column: NAME
Type: VARCHAR2(30)
Number of Exceptions: 2
Max Post Conversion Data Size: 11
ROWID Exception Type Size Cell Data(first 30 bytes) Language & Character Set
------------------ ------------------ ----- --------------------------- ------------------------
AAAA2fAAFAABJwQAAt lossy conversion C'est français (French,UTF8)
AAAA2fAAFAABJwQAAu lossy conversion Ciò è italiana (Italian,WE8MSWIN1252)
------------------ ------------------ ----- --------------------------- ------------------------
How to Handle Convertible or Lossy Data in the Data Dictionary
Unlike modifying user application data, updating and changing the contents of data
dictionary tables directly is not supported. Updating the system tables without
understanding the internal dependencies can lead to database corruption.
If the data dictionary is convertible, then the data cells are encoded in the FROMCHAR
character set. Three common scenarios for the existence of convertible data in the data
dictionary are:
■CLOB data in the data dictionary
For single-byte character sets, CLOB data is stored in the database character set
encoding. For multibyte character sets, CLOB data is stored in an internal Oracle
Database format which is compatible with UCS-2. For example, the byte
representation of the string 'ABC' stored inside a VARCHAR2 column in a US7ASCII
See Also:
■"Data Truncation" on page 11-1
■"Character Set Conversion Issues" on page 11-3
How to Handle Convertible or Lossy Data in the Data Dictionary
12-34 Oracle Database Globalization Support Guide
database remains unchanged when migrated to AL32UTF8. The same string
stored inside a CLOB column doubles in size and is stored completely differently.
When migrating from a single-byte character set to a multibyte character set, CLOB
data is never CHANGELESS.
■XML CSX data in the data dictionary
All XML CSX data in the data dictionary can be safely converted like convertible
application data.
■Migrating a database to a character set that is a superset in the sense that it
contains all of the characters of the original character set, but the binary values of
some characters is not the same in the two character sets
This is similar to user application data whose data cells need to be manually
converted to the new character set. A common cause of this is that the user 's
object definitions (such as table names, column names, package names and
package bodies) were created using non-ASCII characters. These are typically
characters or symbols that are part of the user's native language.
The easiest approach to migrating convertible data dictionary data is to create a new
database in the target character set and then re-create all of the data dictionary and
schema definitions by exporting and importing. However, this method means creating
a new database.
If you want to migrate the existing database instead of building a new one, then the
CSALTER script is the simplest way to migrate convertible CLOB data inside the data
dictionary and to change the existing database character set to the target character set.
For data dictionary CONVERTIBLE data cells that are not CLOB data, you must find the
schema objects containing the convertible data. Then you can choose to do one of the
following actions:
■Amend the object definitions (such as removing non-ASCII characters from
comments inside a package body) so that the data cells become CHANGELESS
■Drop these objects from the database schema altogether and then re-create them
after the database character set has been migrated to the target character set
LOSSY dictionary data cells require further examination of the data dictionary to see
whether the current FROMCHAR character set is the actual character set of the database.
If it is, you have to correct these object definitions (such as removing the offending
characters from comments inside a package body) so that the data cells become
CHANGELESS and they can be migrated safely to the target character set.
Three SQL scripts are included with the Database Character Set Scanner to help users
to locate the CONVERTIBLE and LOSSY data cells in the data dictionary:
■analyze_source.sql
■analyze_histgrm.sql
■analyze_rule.sql
The scripts are stored in the $ORACLE_HOME/nls/csscan/sql directory. They
perform SQL SELECT operations on the SYS.SOURCE$, SYS.HISTGRM$ and
SYS.RULE$ data dictionary tables so that the offending data dictionary objects can be
identified.
The following example shows output from the analyze_source.sql script:
See Also: "Database Character Set Scanner CSALTER Script" on
page 12-37
Storage and Performance Considerations in the Database Character Set Scanner
Character Set Scanner Utilities 12-35
SQL> @$ORACLE_HOME/nls/csscan/sql/analyze_source.sql
Table: SYS.SOURCE$
Error: CONVERTIBLE DATA
no rows selected
Table: SYS.SOURCE$
Error: EXCEPTIONAL DATA
OWNER OBJECT_NAME OBJECT_TYPE EXCEPTIONAL
----------- -------------- ------------- -----------
SCOTT FOO FUNCTION 1
Storage and Performance Considerations in the Database Character Set
Scanner
This section describes storage and performance issues in the Database Character Set
Scanner. It contains the following topics:
■Storage Considerations for the Database Character Set Scanner
■Performance Considerations for the Database Character Set Scanner
■Recommendations and Restrictions for the Database Character Set Scanner
Storage Considerations for the Database Character Set Scanner
This section describes the size and the growth of the Database Character Set Scanner's
system tables, and explains the approach to maintain them. There are three system
tables that can increase rapidly depending on the nature of the data stored in the
database.
You may want to assign a large tablespace to the user CSMIG by amending the
csminst.sql script. By default, the SYSTEM tablespace is assigned to the user
CSMIG.
This section includes the following topics:
■CSM$TABLES
■CSM$COLUMNS
■CSM$ERRORS
CSM$TABLES
The Database Character Set Scanner enumerates all tables that need to be scanned into
the CSM$TABLES table.
You can look up the number of tables (to get an estimate of how large CSM$TABLES
can become) in the database by issuing the following SQL statement:
SELECT COUNT(*) FROM DBA_TABLES;
CSM$COLUMNS
The Database Character Set Scanner stores statistical information for each column
scanned into the CSM$COLUMNS table.
You can look up the number of character type columns (to get an estimate of how large
CSM$COLUMNS can become) in the database by issuing the following SQL statement:
Storage and Performance Considerations in the Database Character Set Scanner
12-36 Oracle Database Globalization Support Guide
SELECT COUNT(*) FROM DBA_TAB_COLUMNS
WHERE DATA_TYPE IN ('CHAR', 'VARCHAR2', 'LONG', 'CLOB', 'VARRAY');
CSM$ERRORS
When exceptions are detected with cell data, the Database Character Set Scanner
inserts individual exception information into the CSM$ERRORS table. This information
then appears in the Individual Exception Report and facilitates identifying records to
be modified if necessary.
If your database contains a lot of data that is signaled as Exceptional or
Convertible (when the parameter CAPTURE=Y is set), then the CSM$ERRORS table
can grow very large. You can prevent the CSM$ERRORS table from growing
unnecessarily large by using the SUPPRESS parameter.
The SUPPRESS parameter applies to all tables. The Database Character Set Scanner
suppresses inserting individual Exceptional information after the specified number
of exceptions is inserted. Limiting the number of exceptions to be recorded may not be
useful if the exceptions are spread over different tables.
Performance Considerations for the Database Character Set Scanner
This section describes how to improve performance when scanning the database.
Using Multiple Scan Processes
If you plan to scan a relatively large database, for example, over 50GB, then you might
want to consider using multiple scan processes. This shortens the duration of database
scans by using hardware resources such as CPU and memory available on the
machine. A guideline for determining the number of scan processes to use is to set the
number equal to the CPU_COUNT initialization parameter.
Setting the Array Fetch Buffer Size
The Database Character Set Scanner fetches multiple rows at a time when an array
fetch is allowed. You can usually improve performance by letting the Database
Character Set Scanner use a bigger array fetch buffer. Each process allocates its own
fetch buffer.
Optimizing the QUERY Clause
When the Character Set Scanner is run without specifying the QUERY parameter, each
SELECT operation created by CSSCAN will automatically include a /*+ROWID*/ hint.
This is to enable faster access, so that all data retrieval will be performed using ROWID
when performing table scans. When a QUERY parameter is supplied, the scanner
assumes that the condition in the WHERE clause may already be optimized by other
means, hence the ROWID hint will not be added to the QUERY clause.
To ensure optimal performance when using the QUERY parameter, careful tuning (for
example, creating additional indexes) will be needed in the SELECT statements.
Suppressing Exception and Convertible Log
The Database Character Set Scanner inserts individual Exceptional and
Convertible (when CAPTURE=Y) information into the CSM$ERRORS table. In
general, insertion into the CSM$ERRORS table is more costly than data fetching. If your
database has a lot of data that is signaled as Exceptional or Convertible, then the
Database Character Set Scanner issues many insert statements, causing performance
Database Character Set Scanner CSALTER Script
Character Set Scanner Utilities 12-37
degradation. Oracle recommends setting a limit on the number of exception rows to be
recorded using the SUPPRESS parameter.
Recommendations and Restrictions for the Database Character Set Scanner
All the character-based data in CHAR, VARCHAR2, LONG, CLOB, and VARRAY columns
are stored in the database character set, which is specified with the CREATE
DATABASE statement when the database is first created. However, in some
configurations, it is possible to store data in a different character set from the database
character set either intentionally or unintentionally. This happens most often when the
NLS_LANG character set is the same as the database character set, because in such cases
Oracle Database sends and receives data as is, without conversion or validation being
guaranteed. It can also happen if one of the two character sets is a superset of the
other, in which case many of the code points appear as if they were not converted. For
example, if NLS_LANG is set to WE8ISO8859P1 and the database character set is
WE8MSWIN1252, then all code points except the range 128-159 are preserved through
the client/server conversion.
The same binary code point value can be used to represent different characters
between the different character sets. Most European character sets share liberal use of
the 8-bit range to encode native characters, so it is very possible for a cell to be
reported as convertible but for the wrong reasons. When you set the FROMCHAR
parameter, the assumption is that all character data is encoded in that character set,
but the Database Character Set Scanner may not be able to accurately determine its
validity.
For example, this can occur when the Database Character Set Scanner is used with the
FROMCHAR parameter set to WE8MSWIN1252. This single-byte character set encodes a
character in every available code point so that no matter what data is being scanned,
the scanner always identifies a data cell as being available in the source character set.
Scanning Database Containing Data Not in the Database Character Set
If a database contains data that is not in the database character set, but it is encoded in
another character set, then the Database Character Set Scanner can perform a scan if
the FROMCHAR parameter specifies the encoded character set.
Scanning Database Containing Data from Two or More Character Sets
If a database contains data from more than one character set, then the Database
Character Set Scanner cannot accurately test the effects of changing the database
character set by a single scan. If the data can be divided into separate tables, one for
each character set, then the Database Character Set Scanner can perform multiple table
scans to verify the validity of the data.
For each scan, use a different value of the FROMCHAR parameter to tell the Database
Character Set Scanner to treat all target columns in the table as if they were in the
specified character set.
Database Character Set Scanner CSALTER Script
The CSALTER script is a DBA tool for special character set migration. Similar to the
obsolete ALTER DATABASE CHARACTER SET SQL statement, CSALTER should be
used only by the system administrator. System administrators must run the Database
Character Set Scanner first to confirm that the proper conditions exist for running
CSALTER. Also, the database must be backed up before running CSALTER.
Database Character Set Scanner CSALTER Script
12-38 Oracle Database Globalization Support Guide
To run the CSALTER script, start SQL*Plus and connect to the database whose
character set is to be migrated. Note that the Database Character Set Scanner must be
run before the CSALTER script. Then enter the following command:
sqlplus> @@CSALTER.PLB
The CSALTER script includes the following phases:
■Checking Phase of the CSALTER Script
■Updating Phase of the CSALTER Script
Checking Phase of the CSALTER Script
In the checking phase, the CSALTER script performs the following tasks:
1. It checks whether the user login is SYS. Only user SYS is allowed to run the script.
2. It checks whether a full database scan has been previously run within the last 7
days. If a full database scan has not been previously run, then the script stops and
reports an error. It is the DBA's responsibility to ensure that no one updates the
database between the times when the full database scans and the CSALTER script
is run.
3. It checks whether CLOB columns in the data dictionary that were created by Oracle
Database are changeless or convertible. Convertible CLOB columns occur when
migrating from a single-byte character set to a multibyte character set. If there are
any lossy cells found in CLOB columns in the data dictionary, then the script stops.
The lossy CLOB columns may need to be specially handled; contact Oracle Support
Services for more information.
Any table that belongs to the following schemas is considered to be part of the
data dictionary:
SYS
SYSTEM
CTXSYS
DIP
DMSYS
EXFSYS
LBACSYS
MDSYS
ORDPLUGINS
ORDSYS
SI_INFORMTN_SCHEMA
XDB
4. It checks whether all CLOB columns in the Sample Schemas created by Oracle
Database are changeless or convertible. Convertible CLOB columns occur when
migrating from a single-byte character set to a multibyte character set. The tables
that belong to the following schemas are part of the Sample Schemas:
HR
OE
SH
PM
5. It checks whether the CLOB dataype is the only datatype that contains convertible
data in the data dictionary and Sample Schemas. It checks that all other users'
tables have no convertible data for all datatypes including the CLOB datatype.
Database Character Set Scanner Views
Character Set Scanner Utilities 12-39
Because the CSALTER script is meant to be run only when the current database is a
proper subset of the new database, all data should be changeless with the possible
exception of the CLOB data. When migrating from a single-byte character set to a
multibyte character set, user-created CLOB data requires conversion and must first
be exported and deleted from the schema. The database must be rescanned in
order to run the CSALTER script. Cells of all other datatypes that are reported to be
convertible or subject to truncation must be corrected before the Database
Character Set Scanner is rerun.
Updating Phase of the CSALTER Script
After the CSALTER script confirms that every CLOB in the data dictionary passes the
checks described in "Checking Phase of the CSALTER Script" on page 12-38, the
CSALTER script performs the conversion. After all CLOB data in the data dictionary
and the Sample Schemas have been updated, the script commits the change and saves
the information in the CSM$TABLES view. After all CLOB data in the data dictionary
have been updated, the CSALTER script updates the database metadata to the new
character set. The entire migration process is then completed.
The CSALTER script is resumable. If the update of the database to the new character
set fails at any time, then the DBA must shut down and restart the database and rerun
the CSALTER script before doing anything else. Because the updated information is
already saved in the CSM$TABLES view, the script will not update the CLOB data in the
data dictionary tables twice. The process of migration is simply resumed to finish the
update of the database to the new character set.
If the CSALTER script fails, then use the following method to resume the update:
1. From the SQL*Plus session where the CSALTER script was run, enter the following
command immediately:
SHUTDOWN ABORT
2. Start up the database and open it, because CSALTER requires an open database.
STARTUP OPEN
3. Run the CSALTER script:
@@CSALTER.PLB
4. Shut down the database with either the IMMEDIATE or the NORMAL option.
5. Start up the database.
Database Character Set Scanner Views
The Database Character Set Scanner uses the following views:
■CSMV$COLUMNS
■CSMV$CONSTRAINTS
■CSMV$ERRORS
See Also:
■"Subsets and Supersets" on page A-16
■"Migrating a Character Set Using the CSALTER Script" on
page 11-6 for more information about the CSALTER script and
CLOB data
Database Character Set Scanner Views
12-40 Oracle Database Globalization Support Guide
■CSMV$INDEXES
■CSMV$TABLES
CSMV$COLUMNS
This view contains statistical information about columns that were scanned.
CSMV$CONSTRAINTS
This view contains statistical information about constraints that were scanned.
Column Name Datatype NULL Description
OWNER_ID NUMBER NOT NULL User ID of the table owner
OWNER_NAME VARCHAR2(30) NOT NULL User name of the table owner
TABLE_ID NUMBER NOT NULL Object ID of the table
TABLE_NAME VARCHAR2(30) NOT NULL Object name of the table
COLUMN_ID NUMBER NOT NULL Column ID
COLUMN_INTID NUMBER NOT NULL Internal column ID (for abstract datatypes)
COLUMN_NAME VARCHAR2(30) NOT NULL Column name
COLUMN_TYPE VARCHAR2(9) NOT NULL Column datatype
TOTAL_ROWS NUMBER NOT NULL Number of rows in this table
NULL_ROWS NUMBER NOT NULL Number of NULL data cells
CONV_ROWS NUMBER NOT NULL Number of data cells that need to be converted
ERROR_ROWS NUMBER NOT NULL Number of data cells that have exceptions
EXCEED_SIZE_ROWS NUMBER NOT NULL Number of data cells that have truncations
DATA_LOSS_ROWS NUMBER - Number of data cells that undergo lossy
conversion
MAX_POST_CONVERT_
SIZE
NUMBER - Maximum post-conversion data size
Column Name Datatype NULL Description
OWNER_ID NUMBER NOT NULL User ID of the constraint owner
OWNER_NAME VARCHAR2(30) NOT NULL User name of the constraint owner
CONSTRAINT_ID NUMBER NOT NULL Object ID of the constraint
CONSTRAINT_NAME VARCHAR2(30) NOT NULL Object name of the constraint
CONSTRAINT_TYPE# NUMBER NOT NULL Constraint type number
CONSTRAINT_TYPE VARCHAR2(11) NOT NULL Constraint type name
TABLE_ID NUMBER NOT NULL Object ID of the table
TABLE_NAME VARCHAR2(30) NOT NULL Object name of the table
CONSTRAINT_RID NUMBER NOT NULL Root constraint ID
CONSTRAINT_LEVEL NUMBER NOT NULL Constraint level
Database Character Set Scanner Views
Character Set Scanner Utilities 12-41
CSMV$ERRORS
This view contains individual exception information for cell data and object
definitions.
CSMV$INDEXES
This view contains individual exception information for indexes.
CSMV$TABLES
This view contains information about database tables to be scanned. The Database
Character Set Scanner enumerates all tables to be scanned into this view.
Column Name Datatype NULL Description
OWNER_ID NUMBER NOT NULL User ID of the table owner
OWNER_NAME VARCHAR2(30) NOT NULL User name of the table owner
TABLE_ID NUMBER NOT NULL Object ID of the table
TABLE_NAME VARCHAR2(30) - Object name of the table
COLUMN_ID NUMBER - Column ID
COLUMN_INTID NUMBER - Internal column ID (for abstract datatypes)
COLUMN_NAME VARCHAR2(30) - Column name
DATA_ROWID VARCHAR2(1000) - The rowid of the data
COLUMN_TYPE VARCHAR2(9) - Column datatype of object type
ERROR_TYPE VARCHAR2(11) - Type of error encountered
Column Name Datatype NULL Description
INDEX_OWNER_ID NUMBER NOT NULL User ID of the index owner
INDEX_OWNER_NAME VARCHAR2(30) NOT NULL User name of the index owner
INDEX_ID NUMBER NOT NULL Object ID of the index
INDEX_NAME VARCHAR2(30) - Object name of the index
INDEX_STATUS# NUMBER - Status number of the index
INDEX_STATUS VARCHAR2(8) - Status of the index
TABLE_OWNER_ID NUMBER - User ID of the table owner
TABLE_OWNER_NAME VARCHAR2(30) - User name of the table owner
TABLE_ID NUMBER - Object ID of the table
TABLE_NAME VARCHAR2(30) - Object name of the table
COLUMN_ID NUMBER - Column ID
COLUMN_INTID NUMBER - Internal column ID (for abstract datatypes)
COLUMN_NAME VARCHAR2(30) - Column name
Column Name Datatype NULL Description
OWNER_ID NUMBER NOT NULL User ID of the table owner
OWNER_NAME VARCHAR2(30) NOT NULL User name of the table owner
Database Character Set Scanner Error Messages
12-42 Oracle Database Globalization Support Guide
Database Character Set Scanner Error Messages
The Database Character Set Scanner has the following error messages:
CSS-00100: failed to allocate memory size of number (%d)
Cause: An attempt was made to allocate memory with size 0 or a value larger
than the maximum allowed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00101: failed to release memory
Cause: An attempt was made to release memory with an invalid pointer.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00102: failed to release memory, null pointer given
Cause: An attempt was made to release memory with a null pointer.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00105: failed to parse BOUNDARIES parameter
Cause: BOUNDARIES parameter was specified in an invalid format.
Action: Refer to the documentation for the correct syntax.
CSS-00106: failed to parse SPLIT parameter
Cause: SPLIT parameter was specified in an invalid format.
Action: Refer to the documentation for the correct syntax.
CSS-00107: Character set migration utility schema not installed
Cause: CSM$VERSION table not found in the database.
Action: Run CSMINST.SQL on the database.
CSS-00108: Character set migration utility schema not compatible
Cause: Incompatible CSM$* tables found in the database.
Action: Run CSMINST.SQL on the database.
CSS-00110: failed to parse USERID
Cause: USERID parameter was specified in an invalid format.
Action: Refer to the documentation for the correct syntax.
CSS-00111: failed to get RDBMS version
TABLE_ID NUMBER - Object ID of the table
TABLE_NAME VARCHAR2(30) - Object name of the table
MIN_ROWID VARCHAR2(18) - Minimum rowid of the split range of the table
MAX_ROWID VARCHAR2(18) - Maximum rowid of the split range of the table
BLOCKS NUMBER - Number of blocks in the split range
SCAN_COLUMNS NUMBER - Number of columns to be scanned
SCAN_ROWS NUMBER - Number of rows to be scanned
SCAN_START VARCHAR2(8) - Time table scan started
SCAN_END VARCHAR2(8) - Time table scan completed
Column Name Datatype NULL Description
Database Character Set Scanner Error Messages
Character Set Scanner Utilities 12-43
Cause: Failed to retrieve the value of the version of the database.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00112: database version not supported
Cause: The database version was older than release 8.0.5.0.0.
Action: Upgrade the database to release 8.0.5.0.0 or later. Then try again.
CSS-00113: user username (%s) is not allowed to access data dictionary
Cause: The specified user cannot access the data dictionary.
Action: Set O7_DICTIONARY_ACCESSIBILITY parameter to TRUE, or use SYS
user.
CSS-00114: failed to get database character set name characterset_name (%s)
Cause: Failed to retrieve value of NLS_CHARACTERSET or NLS_NCHAR_
CHARACTERSET parameter from NLS_DATABASE_PARAMETERS view.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00115: invalid character set name characterset_name (%s)
Cause: The specified character set was not a valid Oracle character set.
Action: Retry with a valid Oracle character set name.
CSS-00116: failed to reset NLS_LANG or NLS_NCHAR parameter
Cause: Failed to force NLS_LANG character set to be the same as the database
character set.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00117: failed to clear previous scan log
Cause: Failed to delete all rows from CSM$* tables.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00118: failed to save command parameters
Cause: Failed to insert rows into CSM$PARAMETERS table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00119: failed to save scan start time
Cause: Failed to insert a row into CSM$PARAMETERS table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00120: failed to enumerate tables to scan
Cause: Failed to enumerate tables to scan into CSM$TABLES table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00121: failed to save scan complete time
Cause: Failed to insert a row into CSM$PARAMETERS table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00122: failed to create scan report
Cause: Failed to create database scan report.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00123: failed to check if user username (%s) exists
Database Character Set Scanner Error Messages
12-44 Oracle Database Globalization Support Guide
Cause: SELECT statement that checks if the specified user exists in the database
failed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00124: user username (%s) not found
Cause: The specified user does not exist in the database.
Action: Check to make sure that the the user name exists and/or is spelled
correctly.
CSS-00125: failed to check if table username.tablename (%s.%s) not found
Cause: SELECT statement that checks if the specified table exists in the database
failed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00126: table username.tablename (%s.%s) not found
Cause: The specified table does not exist in the database.
Action: Check the user name and table name for correctness.
CSS-00127: user username (%s) does not have DBA privilege
Cause: The specified user did not have DBA privileges, which are required to
scan the database.
Action: Choose a user with DBA privileges.
CSS-00128: failed to get server version string
Cause: Failed to retrieve the version string of the database.
Action: None.
CSS-00129: query cannot be used in ALL or USER scan mode
Cause: The query parameter should not be used with FULL Database Scan and
User Scan mode.
Action: Remove the query parameter.
CSS-00130: failed to initialize semaphore
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00131: failed to spawn scan process number (%d)
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00132: failed to destroy semaphore
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00133: failed to wait semaphore
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00134: failed to post semaphore
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
Database Character Set Scanner Error Messages
Character Set Scanner Utilities 12-45
CSS-00140: failed to scan table (tid=number (%d), oid=number (%d))
Cause: Data scan on specified table failed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00141: failed to save table scan start time
Cause: Failed to update a row in the CSM$TABLES table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00142: failed to get table information
Cause: Failed to retrieve various information from userID and object ID of the
table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00143: failed to get column attributes
Cause: Failed to retrieve column attributes of the table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00144: failed to scan table username.tablename (%s.%s)
Cause: Data scan on specified table failed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00145: failed to save scan result for columns
Cause: Failed to insert rows into CSM$COLUMNS table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00146: failed to save scan result for table
Cause: Failed to update a row of CSM$TABLES table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00147: unexpected data truncation
Cause: Scanner allocated the exactly same size of memory as the column byte size
for fetch buffer, resulting in unexpected data truncation.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00150: failed to enumerate table
Cause: Failed to retrieve the specified table information.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00151: failed to enumerate user tables
Cause: Failed to enumerate all tables that belong to the specified user.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00152: failed to enumerate all tables
Cause: Failed to enumerate all tables in the database.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00153: failed to enumerate character type columns
Cause: Failed to enumerate all CHAR, VARCHAR2, LONG, and CLOB columns of
tables to scan.
Action: This is an internal error. Contact Oracle Support Services.
Database Character Set Scanner Error Messages
12-46 Oracle Database Globalization Support Guide
CSS-00154: failed to create list of tables to scan
Cause: Failed to enumerate the tables into CSM$TABLES table.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00155: failed to split tables for scan
Cause: Failed to split the specified tables.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00156: failed to get total number of tables to scan
Cause: SELECT statement that retrieves the number of tables to scan failed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00157: failed to retrieve list of tables to scan
Cause: Failed to read all table IDs into the scanner memory.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00158: failed to retrieve index defined on column
Cause: SELECT statement that retrieves index defined on the column failed.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00160: failed to open summary report file
Cause: FILE OPEN function returned error.
Action: Check if you have create or write privilege on the disk and check if the file
name specified for the LOG parameter is valid.
CSS-00161: failed to report scan elapsed time
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00162: failed to report database size information
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00163: failed to report scan parameters
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00164: failed to report scan summary
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00165: failed to report conversion summary
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00166: failed to report conversion per table and column
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00167: failed to open exception report file
Cause: FILE OPEN function returned error.
Database Character Set Scanner Error Messages
Character Set Scanner Utilities 12-47
Action: Check if you have create or write privilege on the disk and check if the file
name specified for LOG parameter is valid.
CSS-00168: failed to report individual exceptions
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00170: failed to retrieve size of tablespace tablespacename (%s)
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00171: failed to retrieve free size of tablespace tablespacename (%s)
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00172: failed to retrieve total size of tablespace tablespacename (%s)
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00173: failed to retrieve used size of the database
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00174: scanner capture data not available
Cause: Unknown.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00175: TOCHAR or TONCHAR parameter not specified
Cause: TOCHAR or TONCHAR parameter was not specified.
Action: Specify the TOCHAR or TONCHAR parameter.
CSS-00176: failed to enumerate user tables in bitmapped tablespace
Cause: Failed to enumerate tables in bitmapped tablespace.
Action: This is an internal error. Contact Oracle Support Services.
CSS-00177: failed to retrive max LOB size
Cause: Unknown
Action: This is an internal error. Contact Oracle Support Services.
CSS-00178: failed to check if column username.tablename.columnname(%s.%s.%s)
exists
Cause: SELECT statement that checks if the specified column exists in the
database failed
Action: This is an internal error. Contact Oracle Support Services.
CSS-00179: column %s.%s.%s not found
Cause: The specified column did not exist in the database
Action: Check the user name, table name, and column name.
CSS-00180: failed to check the index on the csm$columns table
Cause: SELECT statement that checks if the index IDX_CSM$COLUMNS exists
failed
Database Character Set Scanner Error Messages
12-48 Oracle Database Globalization Support Guide
Action: This is an internal error. Contact Oracle Support Services.
CSS-00181: failed to drop index on the csm$columns table
Cause: The SQL Statement to drop the index IDX_CSM$COLUMNS failed
Action: This is an internal error. Contact Oracle Support Services.
Customizing Locale Data 13-1
13
Customizing Locale Data
This chapter describes how to customize locale data and includes the following topics:
■Overview of the Oracle Locale Builder Utility
■Creating a New Language Definition with Oracle Locale Builder
■Creating a New Territory Definition with the Oracle Locale Builder
■Displaying a Code Chart with the Oracle Locale Builder
■Creating a New Character Set Definition with the Oracle Locale Builder
■Creating a New Linguistic Sort with the Oracle Locale Builder
■Adding Custom Locale Definitions to Java Components with the GINSTALL
Utility
■Generating and Installing NLB Files
■Deploying Custom NLB Files on Other Platforms
■Upgrading Custom NLB Files from Previous Releases of Oracle Database
■Transporting NLB Data from One Platform to Another
Overview of the Oracle Locale Builder Utility
The Oracle Locale Builder offers an easy and efficient way to customize locale data. It
provides a graphical user interface through which you can easily view, modify, and
define locale-specific data. It extracts data from the text and binary definition files and
presents them in a readable format so that you can process the information without
worrying about the formats used in these files.
The Oracle Locale Builder manages four types of locale definitions: language, territory,
character set, and linguistic sort. It also supports user-defined characters and
customized linguistic rules. You can view definitions in existing text and binary
definition files and make changes to them, or create your own definitions.
This section contains the following topics:
■Configuring Unicode Fonts for the Oracle Locale Builder
■The Oracle Locale Builder User Interface
■Oracle Locale Builder Pages and Dialog Boxes
Overview of the Oracle Locale Builder Utility
13-2 Oracle Database Globalization Support Guide
Configuring Unicode Fonts for the Oracle Locale Builder
The Oracle Locale Builder uses Unicode characters in many of its functions. For
example, it shows the mapping of local character code points to Unicode code points.
Oracle Locale Builder depends on the local fonts that are available on the operating
system where the characters are rendered. Therefore, Oracle recommends that you use
a Unicode font to fully support the Oracle Locale Builder. If a character cannot be
rendered with your local fonts, then it will probably be displayed as an empty box.
Font Configuration on Windows
There are many Windows TrueType and OpenType fonts that support Unicode.
Oracle recommends using the Arial Unicode MS font from Microsoft, because it
includes over 50,000 glyphs and supports most of the characters in Unicode 5.0.
After installing the Unicode font, add the font to the Java Runtime
font.properties file so it can be used by the Oracle Locale Builder. The
font.properties file is located in the $JAVAHOME/jre/lib directory. For
example, for the Arial Unicode MS font, add the following entries to the
font.properties file:
dialog.n=Arial Unicode MS, DEFAULT_CHARSET
dialoginput.n=Arial Unicode MS, DEFAULT_CHARSET
serif.n=Arial Unicode MS, DEFAULT_CHARSET
sansserif.n=Arial Unicode MS, DEFAULT_CHARSET
n is the next available sequence number to assign to the Arial Unicode MS font in the
font list. Java Runtime searches the font mapping list for each virtual font and uses the
first font available on your system.
After you edit the font.properties file, restart the Oracle Locale Builder.
Font Configuration on Other Platforms
There are fewer choices of Unicode fonts for non-Windows platforms than for
Windows platforms. If you cannot find a Unicode font with satisfactory character
coverage, then use multiple fonts for different languages. Install each font and add the
font entries into the font.properties file using the steps described for the
Windows platform.
For example, to display Japanese characters on Sun Solaris using the font ricoh-hg
mincho, add entries to the existing font.properties file in $JAVAHOME/lib in the
dialog, dialoginput, serif, and sansserif sections. For example:
serif.plain.3=-ricoh-hg mincho l-medium-r-normal--*-%d-*-*-m-*-jisx0201.1976-0
See Also: Sun's internationalization Web site for more
information about the font.properties file
Note: Depending on the operating system locale, the
locale-specific font.properties file might be used. For example,
if the current operating system locale is ja_JP.eucJP on Sun
Solaris, then font.properties.ja may be used.
See Also: Your operating system documentation for more
information about available fonts
Overview of the Oracle Locale Builder Utility
Customizing Locale Data 13-3
The Oracle Locale Builder User Interface
Ensure that the ORACLE_HOME parameter is set before starting Oracle Locale Builder.
In the UNIX operating system, start the Oracle Locale Builder by changing into the
$ORACLE_HOME/nls/lbuilder directory and issuing the following command:
% ./lbuilder
In a Windows operating system, start the Oracle Locale Builder from the Start menu as
follows: Start > Programs > Oracle-OraHome10 > Configuration and Migration
Tools > Locale Builder. You can also start it from the DOS prompt by entering the
%ORACLE_HOME%\nls\lbuilder directory and executing the lbuilder.bat
command.
When you start the Oracle Locale Builder, the screen shown in Figure 13–1 appears.
Figure 13–1 Oracle Locale Builder Utility
Oracle Locale Builder Pages and Dialog Boxes
Before using Oracle Locale Builder for a specific task, you should become familiar with
the following tab pages and dialog boxes:
■Existing Definitions Dialog Box
■Session Log Dialog Box
■Preview NLT Tab Page
■Open File Dialog Box
Note: Oracle Locale Builder includes online help.
Overview of the Oracle Locale Builder Utility
13-4 Oracle Database Globalization Support Guide
Existing Definitions Dialog Box
When you choose New Language, New Territory, New Character Set, or New
Linguistic Sort, the first tab page that you see is labelled General. Click Show
Existing Definitions to see the Existing Definitions dialog box.
The Existing Definitions dialog box enables you to open locale objects by name. If you
know a specific language, territory, linguistic sort (collation), or character set that you
want to start with, then click its displayed name. For example, you can open the
AMERICAN language definition file as shown in Figure 13–2.
Figure 13–2 Existing Definitions Dialog Box
Choosing AMERICAN opens the lx00001.nlb file. An NLB file is a binary file that
contains the settings for a specific language, territory, character set, or linguistic sort.
Language and territory abbreviations are for reference only and cannot be opened.
Session Log Dialog Box
Choose Tools > View Log to see the Session Log dialog box. The Session Log dialog
box shows what actions have been taken in the current session. Click Save Log to keep
a record of all changes. Figure 13–3 shows an example of a session log.
Figure 13–3 Session Log Dialog Box
Preview NLT Tab Page
The NLT (National Languare Text) file is an XML file with the file extension .nlt that
stores the settings for a specific language, territory, character set, or linguistic sort. The
Overview of the Oracle Locale Builder Utility
Customizing Locale Data 13-5
Preview NLT tab page presents a readable form of the file so that you can see whether
the changes you have made are correct. You cannot modify the NLT file from the
Preview NLT tab page. You must use the specific tools and procedures available in
Oracle Locale Builder to modify the NLT file.
Figure 13–4 shows an example of the Preview NLT tab page for a user-defined
language called AMERICAN FRENCH.
Figure 13–4 Previewing the NLT File
Open File Dialog Box
You can see the Open File dialog box by choosing File > Open > By File Name. Then
choose the NLB (National Language Binary) file that you want to modify or use as a
template. An NLB file is a binary file with the file extension .nlb that contains the
binary equivalent of the information in the NLT file. Figure 13–5 shows the Open File
dialog box with the lx00001.nlb file selected. The Preview pane shows that this
NLB file is for the AMERICAN language.
Creating a New Language Definition with Oracle Locale Builder
13-6 Oracle Database Globalization Support Guide
Figure 13–5 Open File Dialog Box
Creating a New Language Definition with Oracle Locale Builder
This section shows how to create a new language based on French. This new language
is called AMERICAN FRENCH. First, open FRENCH from the Existing Definitions dialog
box. Then change the language name to AMERICAN FRENCH and the Language
Abbreviation to AF in the General tab page. Retain the default values for the other
fields. Figure 13–6 shows the resulting General tab page.
Figure 13–6 Language General Information
Creating a New Language Definition with Oracle Locale Builder
Customizing Locale Data 13-7
The following restrictions apply when choosing names for locale objects such as
languages:
■Names must contain only ASCII characters
■Names must start with a letter
■Language, territory, and character set names cannot contain underscores
The valid range for the Language ID field for a user-defined language is 1,000 to
10,000. You can accept the value provided by Oracle Locale Builder or you can specify
a value within the range.
Figure 13–7 shows how to set month names using the Month Names tab page.
Figure 13–7 Month Names Tab Page
All names are shown as they appear in the NLT file. If you choose Yes for
capitalization, then the month names are capitalized in your application, but they do
not appear capitalized in the Month Names tab page.
Figure 13–8 shows the Day Names tab page.
Note: Only certain ID ranges are valid values for user-defined
LANGUAGE, TERRITORY, CHARACTER SET, MONOLINGUAL
COLLATION, and MULTILINGUAL COLLATION definitions. The
ranges are specified in the sections of this chapter that concern each
type of user-defined locale object.
Creating a New Language Definition with Oracle Locale Builder
13-8 Oracle Database Globalization Support Guide
Figure 13–8 Day Names Tab Page
You can choose day names for your user-defined language. All names are shown as
they appear in the NLT file. If you choose Yes for capitalization, then the day names
are capitalized in your application, but they do not appear capitalized in the Day
Names tab page.
Figure 13–9 shows the Common Info tab page.
Creating a New Territory Definition with the Oracle Locale Builder
Customizing Locale Data 13-9
Figure 13–9 Common Info Tab Page
You can display the territories, character sets, Windows character sets, and linguistic
sorts that have associations with the current language. In general, the most
appropriate or the most commonly used items are displayed first. For example, with a
language of FRENCH, the common territories are FRANCE, BELGIUM, CANADA,
and DJIBOUTI, while the character sets for supporting French are WE8ISO8859P1,
WE8MSWIN1252, AL32UTF8, and WE8ISO8859P15. As WE8MSWIN1252 is more
common than WE8ISO8859P1 in a Windows environment, it is displayed first.
Creating a New Territory Definition with the Oracle Locale Builder
This section shows how to create a new territory called REDWOOD SHORES and use RS
as a territory abbreviation. The new territory is not based on an existing territory
definition.
The basic tasks are as follows:
■Assign a territory name
■Choose formats for the calendar, numbers, date and time, and currency
Figure 13–10 shows the General tab page with REDWOOD SHORES specified as the
Territory Name, 1001 specified as the Territory ID, and RS specified as the Territory
Abbreviation.
Creating a New Territory Definition with the Oracle Locale Builder
13-10 Oracle Database Globalization Support Guide
Figure 13–10 General Tab Page for Territories
The valid range for Territory ID for a user-defined territory is 1000 to 10000.
Figure 13–11 shows settings for calendar formats in the Calendar tab page.
Creating a New Territory Definition with the Oracle Locale Builder
Customizing Locale Data 13-11
Figure 13–11 Choosing Calendar Formats
Monday is set as the first day of the week, and the first week of the calendar year is set
as an ISO week. Figure 13–11 displays a sample calendar.
Figure 13–12 shows the Date&Time tab page.
See Also:
■"Calendar Formats" on page 3-20 for more information about
choosing the first day of the week and the first week of the
calendar year
■"Customizing Calendars with the NLS Calendar Utility" on
page 13-15 for information about customizing calendars
themselves
Creating a New Territory Definition with the Oracle Locale Builder
13-12 Oracle Database Globalization Support Guide
Figure 13–12 Choosing Date and Time Formats
When you choose a format from a list, Oracle Locale Builder displays an example of
the format. In this case, the Short Date Format is set to DD-MM-YY. The Short Time
Format is set to HH24:MI:SS. The Oracle Date Format is set to DD-MM-YY. The Long
Date Format is set to fmDay, Month dd, yyyy. The TimeStamp Timezone Format
is not set.
You can also enter your own formats instead of using the selection from the
drop-down menus.
Figure 13–13 shows the Number tab page.
See Also:
■"Date Formats" on page 3-15
■"Time Formats" on page 3-17
■"Customizing Time Zone Data" on page 13-15
Creating a New Territory Definition with the Oracle Locale Builder
Customizing Locale Data 13-13
Figure 13–13 Choosing Number Formats
A period has been chosen for the Decimal Symbol. The Negative Sign Location is
specified to be on the left of the number. The Numeric Group Separator is a comma.
The Number Grouping is specified as 3 digits. The List Separator is a comma. The
Measurement System is metric. The Rounding Indicator is 4.
You can enter your own values instead of using values in the lists.
When you choose a format from a list, Oracle Locale Builder displays an example of
the format.
Figure 13–14 shows settings for currency formats in the Monetary tab page.
See Also: "Numeric Formats" on page 3-23
Creating a New Territory Definition with the Oracle Locale Builder
13-14 Oracle Database Globalization Support Guide
Figure 13–14 Choosing Currency Formats
The Local Currency Symbol is set to $. The Alternative Currency Symbol is the euro
symbol. The Currency Presentation shows one of several possible sequences of the
local currency symbol, the debit symbol, and the number. The Decimal Symbol is the
period. The Group Separator is the comma. The Monetary Number Grouping is 3.
The Monetary Precision, or number of digits after the decimal symbol, is 3. The
Credit Symbol is +. The Debit Symbol is -. The International Currency Separator is a
blank space, so it is not visible in the field. The International Currency Symbol (ISO
currency symbol) is USD. Oracle Locale Builder displays examples of the currency
formats you have selected.
You can enter your own values instead of using the lists.
Figure 13–15 shows the Common Info tab page.
See Also: "Currency Formats" on page 3-25
Creating a New Territory Definition with the Oracle Locale Builder
Customizing Locale Data 13-15
Figure 13–15 Common Info Tab Page
You can display the common languages and time zones for the current territory. For
example, with a territory of CANADA, the common languages are ENGLISH,
CANADIAN FRENCH, and FRENCH. The common time zones are
America/Montreal, America/St_Johns, America/Halifax, America/Winnipeg,
America/Regina, America/Edmonton, and America/Vancouver.
The rest of this section contains the following topics:
■Customizing Time Zone Data
■Customizing Calendars with the NLS Calendar Utility
Customizing Time Zone Data
The time zone files contain the valid time zone names. The following information is
included for each time zone:
■Offset from Coordinated Universal Time (UTC)
■Transition times for daylight savings time
■Abbreviations for standard time and daylight savings time. The abbreviations are
used with the time zone names.
Two time zone files are included in the Oracle Database home directory. The default
file is oracore/zoneinfo/timezlrg.dat. The commonly used and smaller time
zones are included in oracore/zoneinfo/timezone.dat.
Customizing Calendars with the NLS Calendar Utility
Oracle Database supports several calendars. All of them are defined with data derived
from globalization support in Oracle Database, but some of them may require the
See Also: "Choosing a Time Zone File" on page 4-15 for more
information about the contents of the time zone files and how to
install the smaller time zone file
Displaying a Code Chart with the Oracle Locale Builder
13-16 Oracle Database Globalization Support Guide
addition of ruler eras or deviation days in the future. To add this information without
waiting for a new release of Oracle Database, you can use an external file that is
automatically loaded when the calendar functions are executed.
Calendar data is first defined in a text file. The text definition file must be converted
into binary format. You can use the NLS Calendar Utility (lxegen) to convert the text
definition file into binary format.
The name of the text definition file and its location for the lxegen utility are
hard-coded and depend on the platform. On UNIX platforms, the file name is
lxecal.nlt. It is located in the $ORACLE_HOME/nls directory. A sample text
definition file is included in the $ORACLE_HOME/nls/demo directory.
The lxegen utility produces a binary file from the text definition file. The name of the
binary file is also hard-coded and depends on the platform. On UNIX platforms, the
name of the binary file is lxecal.nlb. The binary file is generated in the same
directory as the text file and overwrites an existing binary file.
After the binary file has been generated, it is automatically loaded during system
initialization. Do not move or rename the file.
Invoke the calendar utility from the command line as follows:
% lxegen
Displaying a Code Chart with the Oracle Locale Builder
You can display and print the code charts of character sets with the Oracle Locale
Builder. From the opening screen for Oracle Locale Builder, choose File > New >
Character Set. Figure 13–16 shows the resulting screen.
See Also:
■Operating system documentation for the location of the files on
your system
■"Calendar Systems" on page A-22
Displaying a Code Chart with the Oracle Locale Builder
Customizing Locale Data 13-17
Figure 13–16 General Tab Page for Character Sets
Click Show Existing Definitions. Highlight the character set you wish to display.
Figure 13–17 shows the Existing Definitions combo box with US7ASCII highlighted.
Figure 13–17 Choosing US7ASCII in the Existing Definitions Dialog Box
Click Open to choose the character set. Figure 13–18 shows the General tab page when
US7ASCII has been chosen.
Displaying a Code Chart with the Oracle Locale Builder
13-18 Oracle Database Globalization Support Guide
Figure 13–18 General Tab Page When US7ASCII Has Been Chosen
Click the Character Data Mapping tab. Figure 13–19 shows the Character Data
Mapping tab page for US7ASCII.
Displaying a Code Chart with the Oracle Locale Builder
Customizing Locale Data 13-19
Figure 13–19 Character Data Mapping Tab Page for US7ASCII
Click View CodeChart. Figure 13–20 shows the code chart for US7ASCII.
Figure 13–20 US7ASCII Code Chart
Creating a New Character Set Definition with the Oracle Locale Builder
13-20 Oracle Database Globalization Support Guide
It shows the encoded value of each character in the local character set, the glyph
associated with each character, and the Unicode value of each character in the local
character set.
If you want to print the code chart, then click Print Page.
Creating a New Character Set Definition with the Oracle Locale Builder
You can customize a character set to meet specific user needs. You can extend an
existing encoded character set definition. User-defined characters are often used to
encode special characters that represent the following language elements:
■Proper names
■Historical Han characters that are not defined in an existing character set standard
■Vendor-specific characters
■New symbols or characters that you define
This section describes how Oracle Database supports user-defined characters. It
includes the following topics:
■Character Sets with User-Defined Characters
■Oracle Database Character Set Conversion Architecture
■Unicode 5.0 Private Use Area
■User-Defined Character Cross-References Between Character Sets
■Guidelines for Creating a New Character Set from an Existing Character Set
■Example: Creating a New Character Set Definition with the Oracle Locale Builder
Character Sets with User-Defined Characters
User-defined characters are typically supported within East Asian character sets.
These East Asian character sets have at least one range of reserved code points for
user-defined characters. For example, Japanese Shift-JIS preserves 1880 code points for
user-defined characters. They are shown in Table 13–1.
Table 13–1 Shift JIS User-Defined Character Ranges
Japanese Shift JIS User-Defined Character Range Number of Code Points
F040-F07E, F080-F0FC 188
F140-F17E, F180-F1FC 188
F240-F27E, F280-F2FC 188
F340-F37E, F380-F3FC 188
F440-F47E, F480-F4FC 188
F540-F57E, F580-F5FC 188
FF640-F67E, F680-F6FC 188
F740-F77E, F780-F7FC 188
F840-F87E, F880-F8FC 188
F940-F97E, F980-F9FC 188
Creating a New Character Set Definition with the Oracle Locale Builder
Customizing Locale Data 13-21
The Oracle Database character sets listed in Table 13–2 contain predefined ranges that
support user-defined characters.
Oracle Database Character Set Conversion Architecture
The code point value that represents a particular character can vary among different
character sets. A Japanese kanji character is shown in Figure 13–21.
Figure 13–21 Japanese Kanji Character
The following table shows how the character is encoded in different character sets.
Oracle Database defines all character sets with respect to Unicode 5.0 code points. That
is, each character is defined as a Unicode 5.0 code value. Character conversion takes
place transparently by using Unicode as the intermediate form. For example, when a
JA16SJIS client connects to a JA16EUC database, the character shown in Figure 13–21
has the code point value 889F when it is entered from the JA16SJIS client. It is
internally converted to Unicode (with code point value 4E9C), and then converted to
JA16EUC (code point value B0A1).
Unicode 5.0 Private Use Area
Unicode 5.0 reserves the range E000-F8FF for the Private Use Area (PUA). The PUA is
intended for end users’ or vendors’ private use character definition.
User-defined characters can be converted between two Oracle Database character sets
by using Unicode 5.0 PUA as the intermediate form, which is the same as for standard
characters.
Table 13–2 Oracle Database Character Sets with User-Defined Character Ranges
Character Set Name
Number of Code Points Available for User-Defined
Characters
JA16DBCS 4370
JA16EBCDIC930 4370
JA16SJIS 1880
JA16SJISYEN 1880
KO16DBCS 1880
KO16MSWIN949 1880
ZHS16DBCS 1880
ZHS16GBK 2149
ZHT16DBCS 6204
ZHT16MSWIN950 6217
Unicode
Encoding
JA16SJIS
Encoding
JA16EUC
Encoding
JA16DBCS
Encoding
4E9C 889F B0A1 4867
Creating a New Character Set Definition with the Oracle Locale Builder
13-22 Oracle Database Globalization Support Guide
User-Defined Character Cross-References Between Character Sets
Cross-references between different character sets are required when registering
user-defined characters across operating systems. Cross-references ensure that the
user-defined characters can be converted correctly across the different character sets
when they are mapped to a Unicode PUA value.
For example, when registering a user-defined character on both a Japanese Shift-JIS
operating system and a Japanese IBM Host operating system, you may want to assign
the F040 code point on the Shift-JIS operating system and the 6941 code point on the
IBM Host operating system for this character. This is so that Oracle Database can map
this character correctly between the character sets JA16SJIS and JA16DBCS.
User-defined character cross-reference information can be found by viewing the
character set definitions using the Oracle Locale Builder. For example, you can
determine that both the Shift-JIS UDC value F040 and the IBM Host UDC value 6941
are mapped to the same Unicode PUA value E000.
Guidelines for Creating a New Character Set from an Existing Character Set
By default, the Oracle Locale Builder generates the next available character set ID for
you. You can also choose your own character set ID. Use the following format for
naming character set definition NLT files:
lx2dddd.nlt
dddd is the 4-digit character set ID in hex.
When you modify a character set, observe the following guidelines:
■Do not remap existing characters.
■All character mappings must be unique.
■New characters should be mapped into the Unicode private use range e000 to f4ff.
(Note that the actual Unicode 5.0 private use range is e000-f8ff. However, Oracle
Database reserves f500-f8ff for its own private use.)
■No line in the character set definition file can be longer than 80 characters.
If you derive a new character set from an existing Oracle Database character set, then
Oracle recommends using the following character set naming convention:
<Oracle_character_set_name><organization_name>EXT<version>
For example, if a company such as Sun Microsystems adds user-defined characters to
the JA16EUC character set, then the following character set name is appropriate:
JA16EUCSUNWEXT1
The character set name contains the following parts:
■JA16EUC is the character set name defined by Oracle Database
See Also: Appendix B, "Unicode Character Code Assignments"
Note: When you create a new multibyte character set from an
existing character set, use an 8-bit or multibyte character set as the
original character set.
Creating a New Character Set Definition with the Oracle Locale Builder
Customizing Locale Data 13-23
■SUNW represents the organization name (company stock trading abbreviation for
Sun Microsystems)
■EXT specifies that this character set is an extension to the JA16EUC character set
■1 specifies the version
Example: Creating a New Character Set Definition with the Oracle Locale Builder
This section shows how to create a new character set called MYCHARSET with 10001
for its Character Set ID. The example uses the WE8ISO8859P1 character set and adds
10 Chinese characters.
Figure 13–22 shows the General tab page for MYCHARSET.
Figure 13–22 General Tab Page for MYCHARSET
Click Show Existing Definitions and choose the WE8ISO8859P1 character set from
the Existing Definitions dialog box.
The ISO Character Set ID and Base Character Set ID fields are optional. The Base
Character Set ID is used for inheriting values so that the properties of the base
character set are used as a template. The Character Set ID is automatically generated,
but you can override it. The valid range for a user-defined character set ID is 8000 to
8999 or 10000 to 20000.
The ISO Character Set ID field remains blank for user-defined character sets.
Note: If you are using Pro*COBOL, then choose a character set ID
between 8000 and 8999.
Creating a New Character Set Definition with the Oracle Locale Builder
13-24 Oracle Database Globalization Support Guide
In this example, the Base Character Set ID field remains blank. However, you can
specify a character set to use as a template. The settings in the Type Specification tab
page must match the type settings of the base character set that you enter in the Base
Character Set ID field. If the type settings do not match, then you will receive an error
when you generate your custom character set.
Figure 13–23 shows the Type Specification tab page.
Figure 13–23 Type Specification Tab Page
The Character Set Category is ASCII_BASED. The BYTE_UNIQUE button is checked.
When you have chosen an existing character set, the fields for the Type Specification
tab page should already be set to appropriate values. You should keep these values
unless you have a specific reason for changing them. If you need to change the
settings, then use the following guidelines:
■FIXED_WIDTH is used to identify character sets whose characters have a uniform
length.
■BYTE_UNIQUE means that the single-byte range of code points is distinct from
the multibyte range. The code in the first byte indicates whether the character is
single-byte or multibyte. An example is JA16EUC.
■DISPLAY identifies character sets that are used only for display on clients and not
for storage. Some Arabic, Devanagari, and Hebrew character sets are display
character sets.
■SHIFT is used for character sets that require extra shift characters to distinguish
between single-byte characters and multibyte characters.
Creating a New Character Set Definition with the Oracle Locale Builder
Customizing Locale Data 13-25
Figure 13–24 shows how to add user-defined characters.
Figure 13–24 Importing User-Defined Character Data
Open the Character Data Mapping tab page. Highlight the character that you want to
add characters after in the character set. In this example, the 0xff local character
value is highlighted.
You can add one character at a time or use a text file to import a large number of
characters. In this example, a text file is imported. The first column is the local
character value. The second column is the Unicode value. The file contains the
following character values:
88a2 963f
88a3 54c0
88a4 611b
88a5 6328
88a6 59f6
88a7 9022
88a8 8475
88a9 831c
88aa 7a50
88ab 60aa
Choose File > Import > User-Defined Characters Data.
Figure 13–25 shows that the imported characters are added after 0xff in the character
set.
See Also: "Variable-width multibyte encoding schemes" on
page 2-7 for more information about shift-in and shift-out character
sets
Creating a New Linguistic Sort with the Oracle Locale Builder
13-26 Oracle Database Globalization Support Guide
Figure 13–25 New Characters in the Character Set
Creating a New Linguistic Sort with the Oracle Locale Builder
This section shows how to create a new multilingual linguistic sort called
MY_GENERIC_M with a collation ID of 10001. The GENERIC_M linguistic sort is used
as the basis for the new linguistic sort. Figure 13–26 shows how to begin.
Creating a New Linguistic Sort with the Oracle Locale Builder
Customizing Locale Data 13-27
Figure 13–26 General Tab Page for Collation
Settings for the flags are automatically derived. SWAP_WITH_NEXT is relevant for
Thai and Lao sorts. REVERSE_SECONDARY is for French sorts. CANONICAL_
EQUIVALENCE determines whether canonical rules are used. In this example,
CANONICAL_EQUIVALENCE is checked.
The valid range for Collation ID (sort ID) for a user-defined sort is 1000 to 2000 for
monolingual collation and 10000 to 11000 for multilingual collation.
Figure 13–27 shows the Unicode Collation Sequence tab page.
See Also:
■Figure 13–30, "Canonical Rules Dialog Box" for more
information about canonical rules
■Chapter 5, "Linguistic Sorting and String Searching"
Creating a New Linguistic Sort with the Oracle Locale Builder
13-28 Oracle Database Globalization Support Guide
Figure 13–27 Unicode Collation Sequence Tab Page
This example customizes the linguistic sort by moving digits so that they sort after
letters. Complete the following steps:
1. Highlight the Unicode value that you want to move. In Figure 13–27, the \x0034
Unicode value is highlighted. Its location in the Unicode Collation Sequence is
called a node.
2. Click Cut. Select the location where you want to move the node.
3. Click Paste. Clicking Paste opens the Paste Node dialog box, shown in
Figure 13–28.
Figure 13–28 Paste Node Dialog Box
■The Paste Node dialog box enables you to choose whether to paste the node after
or before the location you have selected. It also enables you to choose the level
(Primary, Secondary, or Tertiary) of the node in relation to the node that you want
to paste it next to.
Select the position and the level at which you want to paste the node.
Creating a New Linguistic Sort with the Oracle Locale Builder
Customizing Locale Data 13-29
In Figure 13–28, the After button and the Primary button are selected.
■Click OK to paste the node.
Use similar steps to move other digits to a position after the letters a through z.
Figure 13–29 shows the resulting Unicode Collation Sequence tab page after the digits
0 through 4 have been moved to a position after the letters a through z.
Figure 13–29 Unicode Collation Sequence After Modification
The rest of this section contains the following topics:
■Changing the Sort Order for All Characters with the Same Diacritic
■Changing the Sort Order for One Character with a Diacritic
Changing the Sort Order for All Characters with the Same Diacritic
This example shows how to change the sort order for characters with diacritics. You
can do this by changing the sort for all characters containing a particular diacritic or by
changing one character at a time. This example changes the sort of each character with
a circumflex (for example, û) to be after the same character containing a tilde.
Verify the current sort order by choosing Tools > Canonical Rules. This opens the
Canonical Rules dialog box, shown in Figure 13–30.
Creating a New Linguistic Sort with the Oracle Locale Builder
13-30 Oracle Database Globalization Support Guide
Figure 13–30 Canonical Rules Dialog Box
Figure 13–30 shows how characters are decomposed into their canonical equivalents
and their current sorting orders. For example, û is represented as u plus ^.
In the Oracle Locale Builder collation window (shown in Figure 13–26), click the
Non-Spacing Characters tab. If you use the Non-Spacing Characters tab page, then
changes for diacritics apply to all characters. Figure 13–31 shows the Non-Spacing
Characters tab page.
Figure 13–31 Changing the Sort Order for All Characters with the Same Diacritic
See Also: Chapter 5, "Linguistic Sorting and String Searching" for
more information about canonical rules
Creating a New Linguistic Sort with the Oracle Locale Builder
Customizing Locale Data 13-31
Select the circumflex and click Cut. Click Yes in the Removal Confirmation dialog box.
Select the tilde and click Paste. Choose After and Secondary in the Paste Node dialog
box and click OK.
Figure 13–32 illustrates the new sort order.
Figure 13–32 The New Sort Order for Characters with the Same Diacritic
Changing the Sort Order for One Character with a Diacritic
To change the order of a specific character with a diacritic, insert the character directly
into the appropriate position. Characters with diacritics do not appear in the Unicode
Collation Sequence tab page, so you cannot cut and paste them into the new location.
This example changes the sort order for ä so that it sorts after Z.
Select the Unicode Collation tab. Highlight the character, Z, that you want to put ä
next to. Click Add. The Insert New Node dialog box appears, as shown in
Figure 13–33.
Creating a New Linguistic Sort with the Oracle Locale Builder
13-32 Oracle Database Globalization Support Guide
Figure 13–33 Changing the Sort Order of One Character with a Diacritic
Choose After and Primary in the Insert New Node dialog box. Enter the Unicode code
point value of ä. The code point value is \x00e4. Click OK.
Figure 13–34 shows the resulting sort order.
Generating and Installing NLB Files
Customizing Locale Data 13-33
Figure 13–34 New Sort Order After Changing a Single Character
Generating and Installing NLB Files
After you have defined a new language, territory, character set, or linguistic sort,
generate new NLB files from the NLT files as follows.
1. As the user who owns the files (typically user oracle), back up the NLS
installation boot file (lx0boot.nlb) and the NLS system boot file
(lx1boot.nlb) in the ORA_NLS10 directory. On a UNIX platform, enter
commands similar to the following example:
% setenv ORA_NLS10 $ORACLE_HOME/nls/data
% cd $ORA_NLS10
% cp -p lx0boot.nlb lx0boot.nlb.orig
% cp -p lx1boot.nlb lx1boot.nlb.orig
Note that the -p option preserves the timestamp of the original file.
2. In Oracle Locale Builder, choose Tools > Generate NLB or click the Generate NLB
icon in the left side bar.
3. Click Browse to find the directory where the NLT file is located. The location
dialog box is shown in Figure 13–35.
Figure 13–35 Location Dialog Box
Deploying Custom NLB Files on Other Platforms
13-34 Oracle Database Globalization Support Guide
Do not try to specify an NLT file. Oracle Locale Builder generates an NLB file for
each NLT file.
4. Click OK to generate the NLB files.
Figure 13–36 illustrates the final notification that you have successfully generated
NLB files for all NLT files in the directory.
Figure 13–36 NLB Generation Success Dialog Box
5. Copy the lx1boot.nlb file into the path that is specified by the ORA_NLS10
environment variable. For example, on a UNIX platform, enter a command similar
to the following example:
% cp /directory_name/lx1boot.nlb $ORA_NLS10/lx1boot.nlb
6. Copy the new NLB files into the ORA_NLS10 directory. For example, on a UNIX
platform, enter commands similar to the following example:
% cp /directory_name/lx22710.nlb $ORA_NLS10
% cp /directory_name/lx52710.nlb $ORA_NLS10
7. Restart the database to use the newly created locale data.
8. To use the new locale data on the client side, exit the client and re-invoke the client
after installing the NLB files.
Deploying Custom NLB Files on Other Platforms
When deploying your locale customization files on other Oracle Database installations,
running with the same Oracle Database release, and under the same operating system
platform, you will need to copy all the custom NLB files together with the
lx1boot.nlb file over to the target machine. In order to deploy the custom NLB files
on a different platform, you will need to copy over the custom .NLT files to your new
platform, and then repeat the NLB generation and installation steps as described in the
section "Generating and Installing NLB Files" on page 13-33.
Note: Oracle Locale Builder generates NLB files in the directory
where the NLT files reside, which is typically
../nlsrtl3/admin/data.
See Also: "Locale Data on Demand" on page 1-1 for more
information about the ORA_NLS10 environment variable
Adding Custom Locale Definitions to Java Components with the GINSTALL Utility
Customizing Locale Data 13-35
Upgrading Custom NLB Files from Previous Releases of Oracle Database
Locale definition files are database release-dependent. For example, NLB files from
Oracle Database 9i and Oracle Database 10g are not directly supported in an Oracle
Database 11g Release 1 installation, and so forth. In order to migrate your locale
customization files from a previous release of the database to your current release, you
first need to convert the files into the latest NLT format. This is achieved by loading
the locale customization files (either NLB or NLT), and saving them individually into
NLT files using the current version of the Oracle Locale Builder. Next, you need to
repeat the NLB generation and installation steps as described in the section
"Generating and Installing NLB Files" on page 13-33.
Please note that Oracle Locale Builder can read and process previous versions of the
NLT and NLB files, as well as read and process these files from different platforms.
However, Oracle Locale Builder always saves NLT files and generates NLB files in the
latest format for the release of Oracle Database that you have installed.
Transporting NLB Data from One Platform to Another
NLB files that are generated on one platform can be transported to another platform
by FTP or other copy utilities. The transported NLB files can be used the same way as
the NLB files that were generated on the original platform. For example, NLB files that
are generated on a Solaris platform can be copied by FTP to a Windows platform and
will provide the same functionality there. This is convenient because locale data can be
modified on one platform and copied to other platforms. Note that you must copy all
of the NLB files from one platform to another, not just the files that have been
modified. Also note that "Generating and Installing NLB Files" described on
page 13-33 is performed the same way as in previous releases.
Different binary formats (such as 32-bit, 64-bit, big-endian, little-endian, ASCII, and
EBCDIC) are processed transparently during NLB loading.
Adding Custom Locale Definitions to Java Components with the
GINSTALL Utility
The ginstall utility adds custom character sets, language, territory, and linguistic
sorts to Java components in your applications. You use Locale Builder to define your
custom character sets, language, territory, and linguistic sort. Locale Builder generates
NLT files, which contain the custom definitions. Then to add the custom definitions to
the Java components, you run ginstall to generate gdk_custom.jar. The same
procedures can be used for Oracle Database release 10.2 and 10.1, as well as release
11.1.
To add custom definitions for character set, language, territory, and linguistic sort:
1. Generate the NLT file using Oracle Locale Builder.
■If you are upgrading custom NLB files from a previous release, follow the
procedure described in Upgrading Custom NLB Files from Previous Releases
of Oracle Database on page 13-35.
2. Run ginstall with -add or -a option to generate gdk_custom.jar.
ginstall –[add | a] lx2dddd.nlt
■To generate multiple NLT files:
ginstall -[add | a] lx2dddd.nlt lx2dddd.nlt lx2dddd.nlt
Adding Custom Locale Definitions to Java Components with the GINSTALL Utility
13-36 Oracle Database Globalization Support Guide
3. Copy gdk_custom.jar to the same directory as orai18n.jar or
orai18n-mapping.jar.
To remove a custom definition:
■Run ginstall as follows.
ginstall –[remove | r] <path to gdk_custom.jar> <name of NLT file>
To update a custom definition:
■Run ginstall as follows.
ginstall –[update | u] <path to gdk_custom.jar> <name of NLT file>
Locale Data A-1
A
Locale Data
This appendix lists the languages, territories, character sets, and other locale data
supported by Oracle Database. This appendix includes these topics:
■Languages
■Translated Messages
■Territories
■Character Sets
■Language and Character Set Detection Support
■Linguistic Sorts
■Calendar Systems
■Time Zone Names
■Obsolete Locale Data
You can obtain information about character sets, languages, territories, and linguistic
sorts by querying the V$NLS_VALID_VALUES dynamic performance view.
Languages
Languages in Table A–1 provide support for locale-sensitive information such as:
■Day and month names and their abbreviations
■Symbols for equivalent expressions for A.M., P.M., A.D., and B.C.
■Default sorting sequence for character data when the ORDER BY SQL clause is
specified
■Writing direction (left to right or right to left)
■Affirmative and negative response strings (for example, YES and NO)
By using Unicode databases and datatypes, you can store, process, and retrieve data
for almost all contemporary languages, including many that do not appear in
Table A–1.
See Also: Oracle Database Reference for more information about the
data that can be returned by this view
Languages
A-2 Oracle Database Globalization Support Guide
Table A–1 Oracle Database Supported Languages
Language Name
Language
Abbreviation Default Sort
ALBANIAN sq GENERIC_M
AMERICAN us binary
ARABIC ar ARABIC
ASSAMESE as binary
AZERBAIJANI az AZERBAIJANI
BANGLA bn binary
BELARUSIAN be RUSSIAN
BRAZILIAN PORTUGUESE ptb WEST_EUROPEAN
BULGARIAN bg BULGARIAN
CANADIAN FRENCH frc CANADIAN FRENCH
CATALAN ca CATALAN
CROATIAN hr CROATIAN
CYRILLIC KAZAKH ckk GENERIC_M
CYRILLIC SERBIAN csr GENERIC_M
CYRILLIC UZBEK cuz GENERIC_M
CZECH cs CZECH
DANISH dk DANISH
DUTCH nl DUTCH
EGYPTIAN eg ARABIC
ENGLISH gb binary
ESTONIAN et ESTONIAN
FINNISH sf FINNISH
FRENCH f FRENCH
GERMAN DIN din GERMAN
GERMAN d GERMAN
GREEK el GREEK
GUJARATI gu binary
HEBREW iw HEBREW
HINDI hi binary
HUNGARIAN hu HUNGARIAN
ICELANDIC is ICELANDIC
INDONESIAN in INDONESIAN
IRISH ga binary
ITALIAN i WEST_EUROPEAN
JAPANESE ja binary
KANNADA kn binary
Translated Messages
Locale Data A-3
Translated Messages
Oracle Database error messages have been translated into the languages which are
listed in Table A–2.
KOREAN ko binary
LATIN AMERICAN SPANISH esa SPANISH
LATIN SERBIAN lsr binary
LATIN UZBEK luz GENERIC_M
LATVIAN lv LATVIAN
LITHUANIAN lt LITHUANIAN
MACEDONIAN mk binary
MALAY ms MALAY
MALAYALAM ml binary
MARATHI mr binary
MEXICAN SPANISH esm WEST_EUROPEAN
NORWEGIAN n NORWEGIAN
ORIYA or binary
POLISH pl POLISH
PORTUGUESE pt WEST_EUROPEAN
PUNJABI pa binary
ROMANIAN ro ROMANIAN
RUSSIAN ru RUSSIAN
SIMPLIFIED CHINESE zhs binary
SLOVAK sk SLOVAK
SLOVENIAN sl SLOVENIAN
SPANISH e SPANISH
SWEDISH s SWEDISH
TAMIL ta binary
TELUGU te binary
THAI th THAI_DICTIONARY
TRADITIONAL CHINESE zht binary
TURKISH tr TURKISH
UKRAINIAN uk UKRAINIAN
VIETNAMESE vn VIETNAMESE
Table A–1 (Cont.) Oracle Database Supported Languages
Language Name
Language
Abbreviation Default Sort
Territories
A-4 Oracle Database Globalization Support Guide
Territories
Table A–3 lists the territories that Oracle Database supports.
Table A–2 Oracle Database Supported Messages
Name Abbreviation
ARABIC ar
BRAZILIAN PORTUGUESE ptb
CATALAN ca
CZECH cs
DANISH dk
DUTCH nl
FINNISH sf
FRENCH f
GERMAN d
GREEK el
HEBREW iw
HUNGARIAN hu
ITALIAN i
JAPANESE ja
KOREAN ko
NORWEGIAN n
POLISH pl
PORTUGUESE pt
ROMANIAN ro
RUSSIAN ru
SIMPLIFIED CHINESE zhs
SLOVAK sk
SPANISH e
SWEDISH s
THAI th
TRADITIONAL CHINESE zht
TURKISH tr
Table A–3 Oracle Database Supported Territories
Name Name Name
ALBANIA GREECE PUERTO RICO
ALGERIA HONG KONG QATAR
AMERICA HUNGARY ROMANIA
ARGENTINA ICELAND RUSSIA
Character Sets
Locale Data A-5
Character Sets
The character sets that Oracle Database supports are listed in the following sections
according to three broad categories.
■Recommended Database Character Sets
■Other Character Sets
■Client-Only Character Sets
AUSTRALIA INDIA SAUDI ARABIA
AUSTRIA INDONESIA SERBIA AND MONTENEGRO
AZERBAIJAN IRAQ SINGAPORE
BAHRAIN IRELAND SLOVAKIA
BANGLADESH ISRAEL SLOVENIA
BELARUS ITALY SOMALIA
BELGIUM JAPAN SOUTH AFRICA
BRAZIL JORDAN SPAIN
BULGARIA KAZAKHSTAN SUDAN
CANADA KOREA SWEDEN
CATALONIA KUWAIT SWITZERLAND
CHILE LATVIA SYRIA
CHINA LEBANON TAIWAN
COLOMBIA LIBYA THAILAND
COSTA RICA LITHUANIA THE NETHERLANDS
CROATIA LUXEMBOURG TUNISIA
CYPRUS MALAYSIA TURKEY
CZECH REPUBLIC MAURITANIA UKRAINE
DENMARK MEXICO UNITED ARAB EMIRATES
DJIBOUTI MOROCCO UNITED KINGDOM
ECUADOR NEW ZEALAND UZBEKISTAN
EGYPT NICARAGUA VENEZUELA
EL SALVADOR NORWAY VIETNAM
ESTONIA OMAN YEMEN
FINLAND PANAMA
FRANCE PERU
FYR MACEDONIA PHILIPPINES
GUATEMALA POLAND
GERMANY PORTUGAL
Table A–3 (Cont.) Oracle Database Supported Territories
Name Name Name
Character Sets
A-6 Oracle Database Globalization Support Guide
In addition, common character set subset/superset combinations are listed. Some
character sets can only be used with certain data types. For example, the AL16UTF16
character set can only be used as an NCHAR character set, and not as a database
character set.
Also documented in the comment section are other unique features of the character set
that may be important to users or your database administrator. For example, the
information includes whether the character set supports the euro currency symbol,
whether user-defined characters are supported, and whether the character set is a
strict superset of ASCII. (You can use the CSALTER script to migrate an existing
database to a new character set, only if all of the schema data is a strict subset of the
new character set.)
The key for the comment column of the character set tables is:
SB: single-byte encoding
MB: multibyte encoding
FIXED: fixed-width multibyte encoding
ASCII: strict superset of ASCII
EURO: euro symbol supported
UDC: user-defined characters supported
Oracle Database does not document individual code page layouts. For specific details
about a particular character set, its character repertoire, and code point values, you can
use Oracle Locale Builder. Otherwise, you should refer to the actual national,
international, or vendor-specific standards.
Recommended Database Character Sets
Table A–4 lists the recommended and most commonly used ASCII-based Oracle
Database character sets. The list is ordered alphabetically within their respective
language group.
See Also: Chapter 13, "Customizing Locale Data"
Table A–4 Recommended ASCII Database Character Sets
Name Description Comments
Asian
JA16EUC EUC 24-bit Japanese MB, ASCII
JA16EUCTILDE The same as JA16EUC except for the way that the wave
dash and the tilde are mapped to and from Unicode. MB, ASCII
JA16SJIS Shift-JIS 16-bit Japanese MB, ASCII, UDC
JA16SJISTILDE The same as JA16SJIS except for the way that the wave dash
and the tilde are mapped to and from Unicode. MB, ASCII, UDC
KO16MSWIN949 MS Windows Code Page 949 Korean MB, ASCII, UDC
TH8TISASCII Thai Industrial Standard 620-2533 - ASCII 8-bit SB, ASCII, EURO
VN8MSWIN1258 MS Windows Code Page 1258 8-bit Vietnamese SB, ASCII, EURO
ZHS16GBK GBK 16-bit Simplified Chinese MB, ASCII, UDC
ZHT16HKSCS MS Windows Code Page 950 with Hong Kong
Supplementary Character Set HKSCS-2001 (character set
conversion to and from Unicode is based on Unicode 3.0)
MB, ASCII,
EURO
ZHT16MSWIN950 MS Windows Code Page 950 Traditional Chinese MB, ASCII, UDC
Character Sets
Locale Data A-7
Table A–5 lists the recommended and most commonly used EBCDIC-based Oracle
Database character sets. The list is ordered alphabetically within their respective
language group.
ZHT32EUC EUC 32-bit Traditional Chinese MB, ASCII
European
BLT8ISO8859P13 ISO 8859-13 Baltic SB, ASCII
BLT8MSWIN1257 MS Windows Code Page 1257 8-bit Baltic SB, ASCII, EURO
CL8ISO8859P5 ISO 8859-5 Latin/Cyrillic SB, ASCII
CL8MSWIN1251 MS Windows Code Page 1251 8-bit Latin/Cyrillic SB, ASCII, EURO
EE8ISO8859P2 ISO 8859-2 East European SB, ASCII
EL8ISO8859P7 ISO 8859-7 Latin/Greek SB, ASCII, EURO
EL8MSWIN1253 MS Windows Code Page 1253 8-bit Latin/Greek SB, ASCII, EURO
EE8MSWIN1250 MS Windows Code Page 1250 8-bit East European SB, ASCII, EURO
NE8ISO8859P10 ISO 8859-10 North European SB, ASCII
NEE8ISO8859P4 ISO 8859-4 North and North-East European SB, ASCII
WE8ISO8859P15 ISO 8859-15 West European SB, ASCII, EURO
WE8MSWIN1252 MS Windows Code Page 1252 8-bit West European SB, ASCII, EURO
Middle
Eastern
AR8ISO8859P6 ISO 8859-6 Latin/Arabic SB, ASCII
AR8MSWIN1256 MS Windows Code Page 1256 8-Bit Latin/Arabic SB, ASCII, EURO
IW8ISO8859P8 ISO 8859-8 Latin/Hebrew SB, ASCII
IW8MSWIN1255 MS Windows Code Page 1255 8-bit Latin/Hebrew SB, ASCII, EURO
TR8MSWIN1254 MS Windows Code Page 1254 8-bit Turkish SB, ASCII, EURO
WE8ISO8859P9 ISO 8859-9 West European & Turkish SB, ASCII
Universal
AL32UTF8 Unicode 5.0 UTF-8 Universal character set MB, ASCII,
EURO
Table A–5 Recommended EBCDIC Database Character Sets
Name Description Comments
Asian
JA16DBCS IBM EBCDIC 16-bit Japanese MB, UDC
JA16EBCDIC930 IBM DBCS Code Page 290 16-bit Japanese MB, UDC
KO16DBCS IBM EBCDIC 16-bit Korean MB, UDC
TH8TISEBCDICS Thai Industrial Standard 620-2533-EBCDIC Server 8-bit SB
European
BLT8EBCDIC1112S EBCDIC Code Page 1112 8-bit Server Baltic Multilingual SB
Table A–4 (Cont.) Recommended ASCII Database Character Sets
Name Description Comments
Character Sets
A-8 Oracle Database Globalization Support Guide
Other Character Sets
Table A–6 lists the other ASCII-based Oracle Database character sets. The list is
ordered alphabetically within their language groups.
CE8BS2000 Siemens EBCDIC.DF.04 8-bit Central European SB
CL8BS2000 Siemens EBCDIC.EHC.LC 8-bit Cyrillic SB
CL8EBCDIC1025R EBCDIC Code Page 1025 Server 8-bit Cyrillic SB
CL8EBCDIC1158R EBCDIC Code Page 1158 Server 8-bit Cyrillic SB
D8EBCDIC1141 EBCDIC Code Page 1141 8-bit Austrian German SB, EURO
DK8DBCDIC1142 EBCDIC Code Page 1142 8-bit Danish SB, EURO
EE8BS2000 Siemens EBCDIC.DF.04 8-bit East European SB
EE8EBCDIC870S EBCDIC Code Page 870 Server 8-bit East European SB
EL8EBCDIC423R IBM EBCDIC Code Page 423 for RDBMS server-side SB
EL8EBCDIC875R EBCDIC Code Page 875 Server 8-bit Greek SB
F8EBCDIC1147 EBCDIC Code Page 1147 8-bit French SB, EURO
I8EBCDIC1144 EBCDIC Code Page 1144 8-bit Italian SB, EURO
S8EBCDCI1143 EBCDIC Code Page 1143 8-bit Swedish SB, EURO
WE8BS2000 Siemens EBCDIC.DF.04 8-bit West European SB
WE8BS2000E Siemens EBCDIC.DF.04 8-bit West European SB, EURO
WE8BS2000L5 Siemens EBCDIC.DF.L5 8-bit West European/Turkish SB
WE8EBCDIC1047E Latin 1/Open Systems 1047 SB, EBCDIC,
EURO
WE8EBCDIC1140 EBCDIC Code Page 1140 8-bit West European SB, EURO
WE8EBCDIC1145 EBCDIC Code Page 1145 8-bit West European SB, EURO
WE8DBCDIC1146 EBCDIC Code Page 1146 8-bit West European SB, EURO
WE8EBCDIC1148 EBCDIC Code Page 1148 8-bit West European SB, EURO
Middle
Eastern
AR8EBCDIC420S EBCDIC Code Page 420 Server 8-bit Latin/Arabic SB
IW8EBCDIC424S EBCDIC Code Page 424 Server 8-bit Latin/Hebrew SB
TR8EBCDIC1026S EBCDIC Code Page 1026 Server 8-bit Turkish SB
Table A–6 Other ASCII-based Database Character Sets
Name Description Comments
Asian
BN8BSCII Bangladesh National Code 8-bit BSCII SB, ASCII
IN8ISCII Multiple-Script Indian Standard 8-bit Latin/Indian
Languages SB, ASCII
JA16VMS JVMS 16-bit Japanese MB, ASCII
Table A–5 (Cont.) Recommended EBCDIC Database Character Sets
Name Description Comments
Character Sets
Locale Data A-9
KO16KSC5601 KSC5601 16-bit Korean MB, ASCII
KO16KSCCS KSCCS 16-bit Korean MB, ASCII
TH8MACTHAIS Mac Server 8-bit Latin/Thai SB, ASCII
VN8VN3 VN3 8-bit Vietnamese SB, ASCII
ZHS16CGB231280 CGB2312-80 16-bit Simplified Chinese MB, ASCII
ZHT16BIG5 BIG5 16-bit Traditional Chinese MB, ASCII
ZHT16CCDC HP CCDC 16-bit Traditional Chinese MB, ASCII
ZHT16DBT Taiwan Taxation 16-bit Traditional Chinese MB, ASCII
ZHT16HKSCS31 MS Windows Code Page 950 with Hong Kong
Supplementary Character Set HKSCS-2001 (character set
conversion to and from Unicode is based on Unicode 3.1)
MB, ASCII,
EURO
ZHT32SOPS SOPS 32-bit Traditional Chinese MB, ASCII
ZHT32TRIS TRIS 32-bit Traditional Chinese MB, ASCII
Middle
Eastern
AR8ADOS710 Arabic MS-DOS 710 Server 8-bit Latin/Arabic SB, ASCII
AR8ADOS720 Arabic MS-DOS 720 Server 8-bit Latin/Arabic SB, ASCII
AR8APTEC715 APTEC 715 Server 8-bit Latin/Arabic SB, ASCII
AR8ASMO8X ASMO Extended 708 8-bit Latin/Arabic SB, ASCII
AR8ISO8859P6 ISO 8859-6 Latin/Arabic SB, ASCII
AR8MUSSAD768 Mussa'd Alarabi/2 768 Server 8-bit Latin/Arabic SB, ASCII
AR8NAFITHA711 Nafitha Enhanced 711 Server 8-bit Latin/Arabic SB, ASCII
AR8NAFITHA721 Nafitha International 721 Server 8-bit Latin/Arabic SB, ASCII
AR8SAKHR706 SAKHR 706 Server 8-bit Latin/Arabic SB, ASCII
AR8SAKHR707 SAKHR 707 Server 8-bit Latin/Arabic SB, ASCII
AZ8ISO8859PE ISO 8859-9 Latin Azerbaijani SB, ASCII
IN8ISCII Multiple-Script Indian Standard 8-bit Latin/Indian
Languages SB, ASCII
IW8MACHEBREW Mac Client 8-bit Hebrew SB
IW8PC1507 IBM-PC Code Page 1507/862 8-bit Latin/Hebrew SB, ASCII
LA8ISO6937 ISO 6937 8-bit Coded Character Set for Text
Communication SB, ASCII
TR8DEC DEC 8-bit Turkish SB, ASCII
TR8PC857 IBM-PC Code Page 857 8-bit Turkish SB, ASCII
European
AR8ARABICMAC Mac Client 8-bit Latin/Arabic SB
AR8ARABICMACS Mac Server 8-bit Latin/Arabic SB, ASCII
BG8MSWIN MS Windows 8-bit Bulgarian Cyrillic SB, ASCII
BG8PC437S IBM-PC Code Page 437 8-bit (Bulgarian Modification) SB, ASCII
Table A–6 (Cont.) Other ASCII-based Database Character Sets
Name Description Comments
Character Sets
A-10 Oracle Database Globalization Support Guide
BLT8CP921 Latvian Standard LVS8-92(1) Windows/Unix 8-bit Baltic SB, ASCII
BLT8PC775 IBM-PC Code Page 775 8-bit Baltic SB, ASCII
CDN8PC863 IBM-PC Code Page 863 8-bit Canadian French SB, ASCII
CEL8ISO8859P14 ISO 8859-13 Celtic SB, ASCII
CL8ISOIR111 ISOIR111 Cyrillic SB
CL8KOI8R RELCOM Internet Standard 8-bit Latin/Cyrillic SB, ASCII
CL8KOI8U KOI8 Ukrainian Cyrillic SB
CL8MACCYRILLICS Mac Server 8-bit Latin/Cyrillic SB, ASCII
EE8MACCES Mac Server 8-bit Central European SB, ASCII
EE8MACCROATIANS Mac Server 8-bit Croatian SB, ASCII
EE8PC852 IBM-PC Code Page 852 8-bit East European SB, ASCII
EL8DEC DEC 8-bit Latin/Greek SB
EL8MACGREEKS Mac Server 8-bit Greek SB, ASCII
EL8PC437S IBM-PC Code Page 437 8-bit (Greek modification) SB, ASCII
EL8PC851 IBM-PC Code Page 851 8-bit Greek/Latin SB, ASCII
EL8PC869 IBM-PC Code Page 869 8-bit Greek/Latin SB, ASCII
ET8MSWIN923 MS Windows Code Page 923 8-bit Estonian SB, ASCII
HU8ABMOD Hungarian 8-bit Special AB Mod SB, ASCII
HU8CWI2 Hungarian 8-bit CWI-2 SB, ASCII
IS8PC861 IBM-PC Code Page 861 8-bit Icelandic SB, ASCII
IW8ISO8859P8 ISO 8859-8 Latin/Hebrew SB, ASCII
LA8ISO6937 ISO 6937 8-bit Coded Character Set for Text
Communication SB, ASCII
LA8PASSPORT German Government Printer 8-bit All-European Latin SB, ASCII
LT8MSWIN921 MS Windows Code Page 921 8-bit Lithuanian SB, ASCII
LT8PC772 IBM-PC Code Page 772 8-bit Lithuanian (Latin/Cyrillic) SB, ASCII
LT8PC774 IBM-PC Code Page 774 8-bit Lithuanian (Latin) SB, ASCII
LV8PC8LR Latvian Version IBM-PC Code Page 866 8-bit Latin/Cyrillic SB, ASCII
LV8PC1117 IBM-PC Code Page 1117 8-bit Latvian SB, ASCII
LV8RST104090 IBM-PC Alternative Code Page 8-bit Latvian
(Latin/Cyrillic) SB, ASCII
N8PC865 IBM-PC Code Page 865 8-bit Norwegian SB, ASCII
RU8BESTA BESTA 8-bit Latin/Cyrillic SB, ASCII
RU8PC855 IBM-PC Code Page 855 8-bit Latin/Cyrillic SB, ASCII
RU8PC866 IBM-PC Code Page 866 8-bit Latin/Cyrillic SB, ASCII
SE8ISO8859P3 ISO 8859-3 South European SB, ASCII
TR8MACTURKISH Mac Client 8-bit Turkish SB
TR8MACTURKISHS Mac Server 8-bit Turkish SB, ASCII
Table A–6 (Cont.) Other ASCII-based Database Character Sets
Name Description Comments
Character Sets
Locale Data A-11
Table A–7 lists the other EBCDIC-based Oracle Database character sets. The list is
ordered alphabetically within their language groups.
TR8PC857 IBM-PC Code Page 857 8-bit Turkish SB, ASCII
US7ASCII ASCII 7-bit American SB, ASCII
US8PC437 IBM-PC Code Page 437 8-bit American SB, ASCII
WE8DEC DEC 8-bit West European SB, ASCII
WE8DG DG 8-bit West European SB, ASCII
WE8ISO8859P1 ISO 8859-1 West European SB, ASCII
WE8MACROMAN8S Mac Server 8-bit Extended Roman8 West European SB, ASCII
WE8NCR4970 NCR 4970 8-bit West European SB, ASCII
WE8NEXTSTEP NeXTSTEP PostScript 8-bit West European SB, ASCII
WE8PC850 IBM-PC Code Page 850 8-bit West European SB, ASCII
WE8PC858 IBM-PC Code Page 858 8-bit West European SB, ASCII,
EURO
WE8PC860 IBM-PC Code Page 860 8-bit West European SB, ASCII
WE8ROMAN8 HP Roman8 8-bit West European SB, ASCII
Universal
UTF8 Unicode 5.0 UTF-8 Universal character set, CESU-8
compliant MB, ASCII,
EURO
Table A–7 Other EBCDIC-based Database Character Sets
Name Description Comments
Asian
TH8TISEBCDIC Thai Industrial Standard 620-2533 - EBCDIC 8-bit SB
ZHS16DBCS IBM EBCDIC 16-bit Simplified Chinese MB, UDC
ZHT16DBCS IBM EBCDIC 16-bit Traditional Chinese MB, UDC
Middle
Eastern
AR8EBCDICX EBCDIC XBASIC Server 8-bit Latin/Arabic SB
IW8EBCDIC424 EBCDIC Code Page 424 8-bit Latin/Hebrew SB
IW8EBCDIC1086 EBCDIC Code Page 1086 8-bit Hebrew SB
TR8EBCDIC1026 EBCDIC Code Page 1026 8-bit Turkish SB
WE8EBCDIC37C EBCDIC Code Page 37 8-bit Oracle/c SB
European
BLT8EBCDIC1112 EBCDIC Code Page 1112 8-bit Server Baltic Multilingual SB
CL8EBCDIC1025 EBCDIC Code Page 1025 8-bit Cyrillic SB
CL8EBCDIC1025C EBCDIC Code Page 1025 Client 8-bit Cyrillic SB
CL8EBCDIC1025S EBCDIC Code Page 1025 Server 8-bit Cyrillic SB
Table A–6 (Cont.) Other ASCII-based Database Character Sets
Name Description Comments
Character Sets
A-12 Oracle Database Globalization Support Guide
Character Sets that Support the Euro Symbol
Table A–8 lists the character sets that support the Euro symbol.
CL8EBCDIC1025X EBCDIC Code Page 1025 (Modified) 8-bit Cyrillic SB
CL8EBCDIC1158 EBCDIC Code Page 1158 8-bit Cyrillic SB
D8BS2000 Siemens 9750-62 EBCDIC 8-bit German SB
D8EBCDIC273 EBCDIC Code Page 273/1 8-bit Austrian German SB
DK7SIEMENS9780X Siemens 97801/97808 7-bit Danish SB
DK8BS2000 Siemens 9750-62 EBCDIC 8-bit Danish SB
DK8EBCDIC277 EBCDIC Code Page 277/1 8-bit Danish SB
E8BS2000 Siemens 9750-62 EBCDIC 8-bit Spanish SB
EE8EBCDIC870 EBCDIC Code Page 870 8-bit East European SB
EE8EBCDIC870C EBCDIC Code Page 870 Client 8-bit East European SB
EL8EBCDIC875 EBCDIC Code Page 875 8-bit Greek SB
EL8GCOS7 Bull EBCDIC GCOS7 8-bit Greek SB
F8BS2000 Siemens 9750-62 EBCDIC 8-bit French SB
F8EBCDIC297 EBCDIC Code Page 297 8-bit French SB
I8EBCDIC280 EBCDIC Code Page 280/1 8-bit Italian SB
S8BS2000 Siemens 9750-62 EBCDIC 8-bit Swedish SB
S8EBCDIC278 EBCDIC Code Page 278/1 8-bit Swedish SB
US8ICL ICL EBCDIC 8-bit American SB
US8BS2000 Siemens 9750-62 EBCDIC 8-bit American SB
WE8EBCDIC924 Latin 9 EBCDIC 924 SB, EBCDIC
WE8EBCDIC37 EBCDIC Code Page 37 8-bit West European SB
WE8EBCDIC284 EBCDIC Code Page 284 8-bit Latin American/Spanish SB
WE8EBCDIC285 EBCDIC Code Page 285 8-bit West European SB
WE8EBCDIC1047 EBCDIC Code Page 1047 8-bit West European SB
WE8EBCDIC1140C EBCDIC Code Page 1140 8-bit West European SB, EURO
WE8EBCDIC1148C EBCDIC Code Page 1148 Client 8-bit West European SB, EURO
WE8EBCDIC500C EBCDIC Code Page 500 8-bit Oracle/c SB
WE8EBCDIC500 EBCDIC Code Page 500 8-bit West European SB
WE8EBCDIC871 EBCDIC Code Page 871 8-bit Icelandic SB
WE8ICL ICL EBCDIC 8-bit West European SB
WE8GCOS7 Bull EBCDIC GCOS7 8-bit West European SB
Universal
UTFE EBCDIC form of Unicode 5.0 UTF-8 Universal character set
(UTF-EBCDIC) MB, EURO
Table A–7 (Cont.) Other EBCDIC-based Database Character Sets
Name Description Comments
Character Sets
Locale Data A-13
Table A–8 Character Sets that Support the Euro Symbol
Character Set Name Hexadecimal Code Value of the Euro Symbol
AL16UTF16 20AC
AL32UTF8 E282AC
AR8MSWIN1256 80
BLT8MSWIN1257 80
CL8EBCDIC1158 E1
CL8EBCDIC1158R 9F
CL8MSWIN1251 88
D8EBCDIC1141 9F
DK8EBCDIC1142 5A
EE8MSWIN1250 80
EL8EBCDIC423R FD
EL8EBCDIC875R DF
EL8ISO8859P7 A4
EL8MSWIN1253 80
F8EBCDIC1147 9F
I8EBCDIC1144 9F
IW8MSWIN1255 80
KO16KSC5601 A2E6
KO16KSCCS D9E6
KO16MSWIN949 A2E6
S8EBCDIC1143 5A
TH8TISASCII 80
TR8MSWIN1254 80
UTF8 E282AC
UTFE CA4653
VN8MSWIN1258 80
WE8BS2000E 9F
WE8EBCDIC1047E 9F
WE8EBCDIC1140 9F
WE8EBCDIC1140C 9F
WE8EBCDIC1145 9F
WE8EBCDIC1146 9F
WE8EBCDIC1148 9F
WE8EBCDIC1148C 9F
WE8EBCDIC924 9F
WE8ISO8859P15 A4
Character Sets
A-14 Oracle Database Globalization Support Guide
Client-Only Character Sets
Table A–9 lists the Oracle Database character sets that are supported as client-only
character sets. The list is ordered alphabetically within their respective language
groups.
WE8MACROMAN8 DB
WE8MACROMAN8S DB
WE8MSWIN1252 80
WE8PC858 DF
ZHS32GB18030 A2E3
ZHT16HKSCS A3E1
ZHT16HKSCS31 A3E1
ZHT16MSWIN950 A3E1
Table A–9 Client-Only Character Sets
Name Description Comments
Asian
JA16EUCYEN EUC 24-bit Japanese with '\' mapped to the Japanese yen
character MB
JA16MACSJIS Mac client Shift-JIS 16-bit Japanese MB
JA16SJISYEN Shift-JIS 16-bit Japanese with '\' mapped to the Japanese
yen character MB, UDC
TH8MACTHAI Mac Client 8-bit Latin/Thai SB
ZHS32GB18030 GB18030-2000 MB, ASCII,
EURO
ZHS16MACCGB231280 Mac client CGB2312-80 16-bit Simplified Chinese MB
European
CH7DEC DEC VT100 7-bit Swiss (German/French) SB
CL8MACCYRILLIC Mac Client 8-bit Latin/Cyrillic SB
D7SIEMENS9780X Siemens 97801/97808 7-bit German SB
D7DEC DEC VT100 7-bit German SB
EEC8EUROASCI EEC Targon 35 ASCI West European/Greek SB
EEC8EUROPA3 EEC EUROPA3 8-bit West European/Greek SB
EE8MACCROATIAN Mac Client 8-bit Croatian SB
EE8MACCE Mac Client 8-bit Central European SB
EL8PC737 IBM-PC Code Page 737 8-bit Greek/Latin SB
EL8MACGREEK Mac Client 8-bit Greek SB
E7DEC DEC VT100 7-bit Spanish SB
E7SIEMENS9780X Siemens 97801/97808 7-bit Spanish SB
F7DEC DEC VT100 7-bit French SB
Table A–8 (Cont.) Character Sets that Support the Euro Symbol
Character Set Name Hexadecimal Code Value of the Euro Symbol
Character Sets
Locale Data A-15
Universal Character Sets
Table A–10 lists the Oracle Database character sets that provide universal language
support. They attempt to support all languages of the world, including, but not limited
to, Asian, European, and Middle Eastern languages.
F7SIEMENS9780X Siemens 97801/97808 7-bit French SB
I7DEC DEC VT100 7-bit Italian SB
I7SIEMENS9780X Siemens 97801/97808 7-bit Italian SB
IS8MACICELANDICS Mac Server 8-bit Icelandic SB
IS8MACICELANDIC Mac Client 8-bit Icelandic SB
NL7DEC DEC VT100 7-bit Dutch SB
NDK7DEC DEC VT100 7-bit Norwegian/Danish SB
N7SIEMENS9780X Siemens 97801/97808 7-bit Norwegian SB
SF7DEC DEC VT100 7-bit Finnish SB
S7SIEMENS9780X Siemens 97801/97808 7-bit Swedish SB
S7DEC DEC VT100 7-bit Swedish SB
SF7ASCII ASCII 7-bit Finnish SB
TR7DEC DEC VT100 7-bit Turkish SB
WE8ISOICLUK ICL special version ISO8859-1 SB
WE8MACROMAN8 Mac Client 8-bit Extended Roman8 West European SB
WE8HP HP LaserJet 8-bit West European SB
YUG7ASCII ASCII 7-bit Yugoslavian SB
Middle
Eastern
AR8ARABICMAC Mac Client 8-bit Latin/Arabic SB
AR8MUSSAD768 Mussa'd Alarabi/2 768 Server 8-bit Latin/Arabic SB, ASCII
IW7IS960 Israeli Standard 960 7-bit Latin/Hebrew SB
IW8MACHEBREW Mac Client 8-bit Hebrew SB
TR8MACTURKISH Mac Client 8-bit Turkish SB
Table A–10 Universal Character Sets
Name Description Comments
AL16UTF16 Unicode 5.0 UTF-16 Universal character set MB, EURO, FIXED
AL32UTF8 Unicode 5.0 UTF-8 Universal character set MB, ASCII, EURO
UTF8 Unicode 5.0 UTF-8 Universal character set, CESU-8 compliant MB, ASCII, EURO
UTFE EBCDIC form of Unicode 5.0 UTF-8 Universal character set
(UTF-EBCDIC) MB, EURO
Table A–9 (Cont.) Client-Only Character Sets
Name Description Comments
Character Sets
A-16 Oracle Database Globalization Support Guide
Character Set Conversion Support
The following character set encodings are supported for conversion only. They cannot
be used as the database or national character set:
AL16UTF16LE
ISO2022-CN
ISO2022-JP
ISO2022-KR
HZ-GB-2312
You can use these character sets as the source_char_set or dest_char_set in the
CONVERT function.
See Oracle Database SQL Reference for more information about the CONVERT function
and "The CONVERT Function" on page 9-4.
Subsets and Supersets
Table A–11 lists common subset/superset relationships.
Note: CESU-8 defines an encoding scheme for Unicode that is
identical to UTF-8 except for its representation of supplementary
characters. In CESU-8, supplementary characters are represented as
six-byte sequences that result from the transformation of each
UTF-16 surrogate code unit into an eight-bit form that is similar to
the UTF-8 transformation, but without first converting the input
surrogate pairs to a scalar value. See Unicode Technical Report #26.
See Also: Chapter 6, "Supporting Multilingual Databases with
Unicode"
Table A–11 Subset-Superset Pairs
Subset Superset
AR8ARABICMACT AR8ARABICMAC
AR8ISO8859P6 AR8ASMO8X
BLT8CP921 BLT8ISO8859P13
BLT8CP921 LT8MSWIN921
D7DEC D7SIEMENS9780X
D7SIEMENS9780X D7DEC
DK7SIEMENS9780X N7SIEMENS9780X
I7DEC I7SIEMENS9780X
I7SIEMENS9780X IW8EBCDIC424
IW8EBCDIC424 IW8EBCDIC1086
KO16KSC5601 KO16MSWIN949
LT8MSWIN921 BLT8ISO8859P13
LT8MSWIN921 BLT8CP921
N7SIEMENS9780X DK7SIEMENS9780X
Character Sets
Locale Data A-17
US7ASCII is a special case because so many other character sets are supersets of it.
Table A–12 lists supersets for US7ASCII.
US7ASCII See Table A–12, " US7ASCII Supersets".
UTF8 AL32UTF8
WE8DEC TR8DEC
WE8DEC WE8NCR4970
WE8ISO8859P1 WE8MSWIN1252
WE8ISO8859P9 TR8MSWIN1254
WE8NCR4970 TR8DEC
WE8NCR4970 WE8DEC
WE8PC850 WE8PC858
Table A–12 US7ASCII Supersets
Supersets a-c Supersets e-n Supersets r-z
AL32UTF8 EE8ISO8859P2 RU8BESTA
AR8ADOS710 EE8MACCES RU8PC855
AR8ADOS720 EE8MACCROATIANS RU8PC866
AR8APTEC715 EE8MSWIN1250 SE8ISO8859P3
AR8ARABICMACS EE8PC852 TH8MACTHAIS
AR8ASMO8X EL8DEC TH8TISASCII
AR8ISO8859P6 EL8ISO8859P7 TR8DEC
AR8MSWIN1256 EL8MACGREEKS TR8MACTURKISHS
AR8MUSSAD768 EL8MSWIN1253 TR8MSWIN1254
AR8NAFITHA711 EL8PC437S TR8PC857
AR8NAFITHA721 EL8PC851 US8PC437
AR8SAKHR706 EL8PC869 UTF8
AR8SAKHR707 ET8MSWIN923 VN8MSWIN1258
AZ8ISO8859PE HU8ABMOD VN8VN3
BG8MSWIN HU8CWI2 WE8DEC
BG8PC437S IN8ISCII WE8DG
BLT8CP921 IS8PC861 WE8ISO8859P1
BLT8ISO8859P13 IW8ISO8859P8 WE8ISO8859P15
BLT8MSWIN1257 IW8MACHEBREWS WE8ISO8859P9
BLT8PC775 IW8MSWIN1255 WE8MACROMAN8S
BN8BSCII IW8PC1507 WE8MSWIN1252
CDN8PC863 JA16EUC WE8NCR4970
CEL8ISO8859P14 JA16SJIS WE8NEXTSTEP
Table A–11 (Cont.) Subset-Superset Pairs
Subset Superset
Language and Character Set Detection Support
A-18 Oracle Database Globalization Support Guide
Language and Character Set Detection Support
Table A–13 displays the languages and character sets that are supported by the
language and character set detection in the Character Set Scanner utilities (CSSCAN
and LCSSCAN) and the Globalization Development Kit (GDK).
Each language has several character sets that can be detected.
When the binary values for a language match two or more encodings that have a
subset/superset relationship, the subset character set is returned. For example, if the
language is German and all characters are 7-bit, then US7ASCII is returned instead of
WE8MSWIN1252, WE8ISO8859P15, or WE8ISO8859P1.
When the character set is determined to be UTF-8, the Oracle Database character set
UTF8 is returned by default unless 4-byte characters (supplementary characters) are
detected within the text. If 4-byte characters are detected, then the character set is
reported as AL32UTF8.
CL8ISO8859P5 JA16VMS WE8PC850
CL8KOI8R KO16KSC5601 WE8PC858
CL8KOI8U KO16KSCCS WE8PC860
CL8ISOIR111 KO16MSWIN949 WE8ROMAN8
CL8MACCYRILLICS LA8ISO6937 ZHS16CGB231280
CL8MSWIN1251 LA8PASSPORT ZHS16GBK
LT8MSWIN921 ZHT16BIG5
LT8PC772 ZHT16CCDC
LT8PC774 ZHT16DBT
LV8PC1117 ZHT16HKSCS
LV8PC8LR ZHT16MSWIN950
LV8RST104090 ZHT32EUC
N8PC865 ZHT32SOPS
NE8ISO8859P10 ZHT32TRIS
NEE8ISO8859P4 ZHS32GB18030
Table A–13 Languages and Character Sets Supported by CSSCAN, LCSSCAN, and GDK
Language Character Sets
Arabic AL16UTF16, AL32UTF8, AR8ISO8859P6, AR8MSWIN1256, UTF8
Bulgarian AL16UTF16, AL32UTF8, CL8ISO8859P5, CL8MSWIN1251, UTF8
Catalan AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Croatian AL16UTF16, AL32UTF8, EE8ISO8859P2, EE8MSWIN1250, UTF8
Czech AL16UTF16, AL32UTF8, EE8ISO8859P2, EE8MSWIN1250, UTF8
Danish AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Table A–12 (Cont.) US7ASCII Supersets
Supersets a-c Supersets e-n Supersets r-z
Linguistic Sorts
Locale Data A-19
Linguistic Sorts
Oracle Database offers two kinds of linguistic sorts, monolingual and multilingual. In
addition, monolingual sorts can be extended to handle special cases. These special
cases (represented with a prefix X) typically mean that the characters are sorted
differently from their ASCII values. For example, ch and ll are treated as a single
character in XSPANISH.
Dutch AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
English AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Estonian AL16UTF16, AL32UTF8, NEE8IOS8859P4, UTF8
Finnish AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
French AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
German AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Greek AL16UTF16, AL32UTF8, EL8ISO8859P7, EL8MSWIN1253, UTF8
Hebrew AL16UTF16, AL32UTF8, IW8ISO8859P8, IW8MSWIN1255, UTF8
Hungarian AL16UTF16, AL32UTF8, EE8ISO8859P2, EE8MSWIN1250, UTF8
Italian AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Japanese AL16UTF16, AL32UTF8, ISO2022-JP, JA16EUC, JA16SJIS, UTF8
Korean AL16UTF16, AL32UTF8, ISO2022-KR, KO16KSC5601, KO16MSWIN949, UTF8
Malay AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Norwegian AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Polish AL16UTF16, AL32UTF8, EE8ISO8859P2, EE8MSWIN1250, UTF8
Portuguese AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Romanian AL16UTF16, AL32UTF8, EE8ISO8859P2, EE8MSWIN1250, UTF8
Russian AL16UTF16, AL32UTF8, CL8ISO8859P5, CL8KOI8R, CL8MSWIN1251, UTF8
Simplified Chinese AL16UTF16, AL32UTF8, HZ-GB-2312, UTF8, ZHS16GBK, ZHS16CGB231280
Slovak AL16UTF16, AL32UTF8, EE8ISO8859P2, EE8MSWIN1250, UTF8
Spanish AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Swedish AL16UTF16, AL32UTF8, US7ASCII, UTF8, WE8ISO8859P1, WE8ISO8859P15,
WE8MSWIN1252
Thai AL16UTF16, AL32UTF8, TH8TISASCII, UTF8
Traditional Chinese AL16UTF16, AL32UTF8, UTF8, ZHT16MSWIN950
Turkish AL16UTF16, AL32UTF8, TR8MSWIN1254, UTF8, WE8ISO8859P9
Table A–13 (Cont.) Languages and Character Sets Supported by CSSCAN, LCSSCAN, and GDK
Language Character Sets
Linguistic Sorts
A-20 Oracle Database Globalization Support Guide
All of the linguistic sorts can be also be performed as case-insensitive or
accent-insensitive by appending _CI or _AI to the linguistic sort name.
Table A–14 lists the monolingual linguistic sorts supported by Oracle Database.
See Also: Table A–1, " Oracle Database Supported Languages" on
page A-2 for a list of the default sort for each language
Table A–14 Monolingual Linguistic Sorts
Basic Name Extended Name Special Cases
ARABIC - -
ARABIC_MATCH - -
ARABIC_ABJ_SORT - -
ARABIC_ABJ_MATCH - -
ASCII7 - -
AZERBAIJANI XAZERBAIJANI i, I, lowercase i without dot, uppercase
I with dot
BENGALI - -
BIG5 - -
BINARY - -
BULGARIAN - -
CATALAN XCATALAN æ, AE, ß
CROATIAN XCROATIAN D, L, N, d, l, n, ß
CZECH XCZECH ch, CH, Ch, ß
CZECH_PUNCTUATION XCZECH_
PUNCTUATION ch, CH, Ch, ß
DANISH XDANISH A, ß, Å, å
DUTCH XDUTCH ij, IJ
EBCDIC - -
EEC_EURO - -
EEC_EUROPA3 - -
ESTONIAN - -
FINNISH - -
FRENCH XFRENCH -
GERMAN XGERMAN ß
GERMAN_DIN XGERMAN_DIN ß, ä, ö, ü, Ä, Ö, Ü
GBK - -
GREEK - -
HEBREW - -
HKSCS - -
HUNGARIAN XHUNGARIAN cs, gy, ny, sz, ty, zs, ß, CS, Cs, GY, Gy,
NY, Ny, SZ, Sz, TY, Ty, ZS, Zs
ICELANDIC - -
Linguistic Sorts
Locale Data A-21
Table A–15 lists the multilingual linguistic sorts available in Oracle Database. All of
them include GENERIC_M (an ISO standard for sorting Latin-based characters) as a
base. Multilingual linguistic sorts are used for a specific primary language together
with Latin-based characters. For example, KOREAN_M sorts Korean and Latin-based
characters, but it does not collate Chinese, Thai, or Japanese characters.
INDONESIAN - -
ITALIAN - -
LATIN - -
LATVIAN - -
LITHUANIAN - -
MALAY - -
NORWEGIAN - -
POLISH - -
PUNCTUATION XPUNCTUATION -
ROMANIAN - -
RUSSIAN - -
SLOVAK XSLOVAK dz, DZ, Dz, ß (caron)
SLOVENIAN XSLOVENIAN ß
SPANISH XSPANISH ch, ll, CH, Ch, LL, Ll
SWEDISH - -
SWISS XSWISS ß
TURKISH XTURKISH æ, AE, ß
UKRAINIAN - -
UNICODE_BINARY - -
VIETNAMESE - -
WEST_EUROPEAN XWEST_EUROPEAN ß
Table A–15 Multilingual LInguistic Sorts
Sort Name Description
CANADIAN_M Canadian French sort supports reverse secondary, special expanding characters
DANISH_M Danish sort supports sorting uppercase characters before lowercase characters
FRENCH_M French sort supports reverse sort for secondary
GENERIC_M Generic sorting order which is based on ISO14651 and Unicode canonical equivalence
rules but excluding compatible equivalence rules
JAPANESE_M Japanese sort supports SJIS character set order and EUC characters which are not
included in SJIS
KOREAN_M Korean sort: Hangul characters are based on Unicode binary order. Hanja characters
based on pronunciation order. All Hangul characters are before Hanja characters
SPANISH_M Traditional Spanish sort supports special contracting characters
Table A–14 (Cont.) Monolingual Linguistic Sorts
Basic Name Extended Name Special Cases
Calendar Systems
A-22 Oracle Database Globalization Support Guide
Calendar Systems
By default, most territory definitions use the Gregorian calendar system. Table A–14
lists the other calendar systems supported by Oracle Database.
Figure A–1 shows how March 27, 1998 appears in Japanese Imperial.
THAI_M Thai sort supports swap characters for some vowels and consonants
SCHINESE_RADICAL_M Simplified Chinese sort based on radical as primary order and number of strokes
order as secondary order
SCHINESE_STROKE_M Simplified Chinese sort uses number of strokes as primary order and radical as
secondary order
SCHINESE_PINYIN_M Simplified Chinese PinYin sorting order
TCHINESE_RADICAL_M Traditional Chinese sort based on radical as primary order and number of strokes
order as secondary order
TCHINESE_STROKE_M Traditional Chinese sort uses number of strokes as primary order and radical as
secondary order. It supports supplementary characters.
See Also: Chapter 5, "Linguistic Sorting and String Searching"
Table A–16 Supported Calendar Systems
Name Default Date Format
Character Set Used
For Default Date Format
Japanese Imperial EEYYMMDD JA16EUC
ROC Official EEyymmdd ZHT32EUC
Thai Buddha dd month EE yyyy TH8TISASCII
Persian DD Month YYYY AR8ASMO8X
Arabic Hijrah DD Month YYYY AR8ISO8859P6
English Hijrah DD Month YYYY AR8ISO8859P6
Table A–15 (Cont.) Multilingual LInguistic Sorts
Sort Name Description
Time Zone Names
Locale Data A-23
Figure A–1 Japanese Imperial Example
Time Zone Names
Table A–17 shows the time zone names in the default time zone file that is supplied
with the Oracle Database. The default time zone file is $ORACLE_
HOME/oracore/zoneinfo/timezlrg.dat. Oracle Database also supplies a smaller
time zone file, $ORACLE_HOME/oracore/zoneinfo/timezone/dat. See
Chapter 4, "Datetime Datatypes and Time Zone Support" for more information
regarding time zone files.
Table A–17 Time Zone Names
Time Zone Name
Is It in the
Smaller Time
Zone File? Time Zone Name
Is It in the Smaller
Time Zone File?
Africa/Algiers No Australia/Perth Yes
Africa/Cairo Yes Australia/Queensland Yes
Africa/Casablanca No Australia/South Yes
Africa/Ceuta No Australia/Sydney Yes
Africa/Djibouti No Australia/Tasmania Yes
Africa/Freetown No Australia/Victoria Yes
Africa/Johannesburg No Australia/West Yes
Africa/Khartoum No Australia/Yancowinna Yes
Africa/Mogadishu No Brazil/Acre Yes
Africa/Nairobi No Brazil/DeNoronha Yes
Africa/Nouakchott No Brazil/East Yes
Time Zone Names
A-24 Oracle Database Globalization Support Guide
Africa/Tripoli Yes Brazil/West Yes
Africa/Tunis No CET Yes
Africa/Windhoek No CST Yes
America/Adak Yes CST6CDT Yes
America/Anchorage Yes Canada/Atlantic Yes
America/Anguilla No Canada/Central Yes
America/Araguaina No Canada/East-Saskatchewan Yes
America/Aruba No Canada/Eastern Yes
America/Asuncion No Canada/Mountain Yes
America/Atka Yes Canada/Newfoundland Yes
America/Belem No Canada/Pacific Yes
America/Boa_Vista No Canada/Saskatchewan Yes
America/Bogota No Canada/Yukon Yes
America/Boise No Chile/Continental Yes
America/Buenos_Aires No Chile/EasterIsland Yes
America/Cambridge_Bay No Cuba Yes
America/Cancun No EET Yes
America/Caracas No EST Yes
America/Cayenne No EST5EDT Yes
America/Cayman No Egypt Yes
America/Chicago Yes Eire Yes
America/Chihuahua No Etc/GMT Yes
America/Costa_Rica No Etc/GMT+0 Yes
America/Cuiaba No Etc/GMT+1 Yes
America/Curacao No Etc/GMT+10 Yes
America/Dawson No Etc/GMT+11 Yes
America/Dawson_Creek No Etc/GMT+12 Yes
America/Denver Yes Etc/GMT+2 Yes
America/Detroit Yes Etc/GMT+3 Yes
America/Edmonton Yes Etc/GMT+4 Yes
America/El_Salvador No Etc/GMT+5 Yes
America/Ensenada Yes Etc/GMT+6 Yes
America/Fort_Wayne Yes Etc/GMT+7 Yes
America/Fortaleza No Etc/GMT+8 Yes
America/Godthab No Etc/GMT+9 Yes
America/Goose_Bay No Etc/GMT-0 Yes
Table A–17 (Cont.) Time Zone Names
Time Zone Name
Is It in the
Smaller Time
Zone File? Time Zone Name
Is It in the Smaller
Time Zone File?
Time Zone Names
Locale Data A-25
America/Grand_Turk No Etc/GMT-1 Yes
America/Guadeloupe No Etc/GMT-10 Yes
America/Guatemala No Etc/GMT-11 Yes
America/Guayaquil No - -
America/Halifax Yes Etc/GMT-12 Yes
America/Havana Yes Etc/GMT-13 Yes
America/Indiana/Indianapolis Yes Etc/GMT-2 Yes
America/Indiana/Knox No Etc/GMT-3 Yes
America/Indiana/Marengo No Etc/GMT-4 Yes
America/Indiana/Vevay No Etc/GMT-5 Yes
America/Indianapolis Yes Etc/GMT-6 Yes
America/Inuvik No Etc/GMT-7 Yes
America/Iqaluit No Etc/GMT-8 Yes
America/Jamaica Yes Etc/GMT-9 Yes
America/Juneau No Etc/GMT0 Yes
America/Knox_IN No Etc/Greenwich Yes
America/La_Paz No Europe/Amsterdam No
America/Lima No Europe/Athens No
America/Los_Angeles Yes Europe/Belfast No
America/Louisville No Europe/Belgrade No
America/Maceio No Europe/Berlin No
America/Managua No Europe/Bratislava No
America/Manaus Yes Europe/Brussels No
America/Martinique No Europe/Bucharest No
America/Mazatlan Yes Europe/Budapest No
America/Mexico_City Yes Europe/Copenhagen No
America/Miquelon No Europe/Dublin Yes
America/Montevideo No Europe/Gibraltar No
America/Montreal Yes Europe/Helsinki No
America/Montserrat No Europe/Istanbul Yes
America/New_York Yes Europe/Kaliningrad No
America/Nome No Europe/Kiev No
America/Noronha Yes Europe/Lisbon Yes
America/Panama No Europe/Ljubljana No
America/Phoenix Yes Europe/London Yes
America/Porto_Acre No Europe/Luxembourg No
Table A–17 (Cont.) Time Zone Names
Time Zone Name
Is It in the
Smaller Time
Zone File? Time Zone Name
Is It in the Smaller
Time Zone File?
Time Zone Names
A-26 Oracle Database Globalization Support Guide
America/Porto_Velho No Europe/Madrid No
America/Puerto_Rico No Europe/Minsk No
America/Rankin_Inlet No Europe/Monaco No
America/Regina Yes Europe/Moscow Yes
America/Rio_Branco Yes - -
America/Santiago Yes Europe/Oslo No
America/Sao_Paulo Yes Europe/Paris No
America/Scoresbysund No Europe/Prague No
America/Shiprock Yes Europe/Riga No
America/St_Johns Yes Europe/Rome No
America/St_Thomas No Europe/Samara No
America/Swift_Current No Europe/San_Marino No
America/Tegucigalpa No Europe/Sarajevo No
America/Thule No Europe/Simferopol No
America/Thunder_Bay No Europe/Skopje No
America/Tijuana Yes Europe/Sofia No
America/Tortola No Europe/Stockholm No
America/Vancouver Yes Europe/Tallinn No
America/Virgin No Europe/Tirane No
America/Whitehorse Yes Europe/Vatican No
America/Winnipeg Yes Europe/Vienna No
America/Yellowknife No Europe/Vilnius No
Arctic/Longyearbyen No Europe/Warsaw Yes
Asia/Aden No Europe/Zagreb No
Asia/Almaty No Europe/Zurich No
Asia/Amman No GB Yes
Asia/Anadyr No GB-Eire Yes
Asia/Aqtau No GMT Yes
Asia/Aqtobe No GMT+0 Yes
Asia/Baghdad No GMT-0 Yes
Asia/Bahrain No GMT0 Yes
Asia/Baku No Greenwich Yes
Asia/Bangkok No HST Yes
Asia/Beirut No Hongkong Yes
Asia/Bishkek No Iceland Yes
Asia/Calcutta Yes Indian/Chagos No
Table A–17 (Cont.) Time Zone Names
Time Zone Name
Is It in the
Smaller Time
Zone File? Time Zone Name
Is It in the Smaller
Time Zone File?
Time Zone Names
Locale Data A-27
Asia/Chongqing No - -
Asia/Chungking No Indian/Christmas No
Asia/Dacca No Indian/Cocos No
Asia/Damascus No Indian/Mayotte No
Asia/Dhaka No - -
Asia/Dubai No Indian/Reunion No
Asia/Gaza No Iran Yes
Asia/Harbin No Israel Yes
Asia/Hong_Kong Yes Jamaica Yes
Asia/Irkutsk No Japan Yes
Asia/Istanbul Yes Kwajalein Yes
Asia/Jakarta No Libya Yes
Asia/Jayapura No MET Yes
Asia/Jerusalem Yes MST Yes
Asia/Kabul No MST7MDT Yes
Asia/Kamchatka No Mexico/BajaNorte Yes
Asia/Karachi No Mexico/BajaSur Yes
Asia/Kashgar No Mexico/General Yes
Asia/Krasnoyarsk No NZ Yes
Asia/Kuala_Lumpur No NZ-CHAT Yes
Asia/Kuching No Navajo Yes
Asia/Kuwait No PRC Yes
Asia/Macao No PST Yes
Asia/Macau No - -
Asia/Magadan No PST8PDT Yes
Asia/Manila No Pacific/Auckland Yes
Asia/Muscat No Pacific/Chatham Yes
Asia/Nicosia No Pacific/Easter Yes
Asia/Novosibirsk No Pacific/Fakaofo No
Asia/Omsk No Pacific/Fiji No
Asia/Qatar No Pacific/Gambier No
Asia/Rangoon No Pacific/Guam No
Asia/Riyadh Yes Pacific/Honolulu Yes
Asia/Saigon No Pacific/Johnston No
Asia/Seoul Yes Pacific/Kiritimati No
Asia/Shanghai Yes Pacific/Kwajalein Yes
Table A–17 (Cont.) Time Zone Names
Time Zone Name
Is It in the
Smaller Time
Zone File? Time Zone Name
Is It in the Smaller
Time Zone File?
Time Zone Names
A-28 Oracle Database Globalization Support Guide
Asia/Singapore Yes Pacific/Marquesas No
Asia/Taipei Yes Pacific/Midway No
Asia/Tashkent No Pacific/Niue No
Asia/Tbilisi No Pacific/Norfolk No
Asia/Tehran Yes Pacific/Noumea No
Asia/Tel_Aviv Yes Pacific/Pago_Pago Yes
Asia/Tokyo Yes Pacific/Pitcairn No
Asia/Ujung_Pandang No Pacific/Rarotonga No
Asia/Urumqi No Pacific/Saipan No
Asia/Vladivostok No Pacific/Samoa Yes
Asia/Yakutsk No Pacific/Tahiti No
Asia/Yekaterinburg No Pacific/Tongatapu No
Asia/Yerevan No Pacific/Wake No
Atlantic/Azores No Pacific/Wallis No
Atlantic/Bermuda No Poland Yes
Atlantic/Canary No Portugal Yes
Atlantic/Faeroe No ROC Yes
Atlantic/Madeira No ROK Yes
Atlantic/Reykjavik Yes Singapore Yes
Atlantic/St_Helena No Turkey Yes
Atlantic/Stanley No US/Alaska Yes
Australia/ACT Yes US/Aleutian Yes
Australia/Adelaide Yes US/Arizona Yes
Australia/Brisbane Yes US/Central Yes
Australia/Broken_Hill Yes US/East-Indiana Yes
Australia/Canberra Yes US/Eastern Yes
Australia/Darwin Yes US/Hawaii Yes
Australia/Hobart Yes US/Indiana-Starke No
Australia/LHI Yes US/Michigan Yes
Australia/Lindeman Yes US/Mountain Yes
Australia/Lord_Howe Yes US/Pacific Yes
Australia/Melbourne Yes US/Pacific-New Yes
Australia/NSW Yes US/Samoa Yes
Australia/North Yes UTC No
--W-SUYes
--WETYes
Table A–17 (Cont.) Time Zone Names
Time Zone Name
Is It in the
Smaller Time
Zone File? Time Zone Name
Is It in the Smaller
Time Zone File?
Obsolete Locale Data
Locale Data A-29
Obsolete Locale Data
This section contains information about obsolete linguistic sorts, character sets,
languages, and territories. The obsolete linguistic sort, language, and territory
definitions are still available. However, they are supported for backward compatibility
only; they may be desupported in a future release. You can obtain a listing of the
obsolete character sets, languages, territories, and linguistic sorts for the current
database release by querying the V$NLS_VALID_VALUES view.
Obsolete Linguistic Sorts
Table A–18 contains linguistic sorts that have been desupported as of Oracle Database
10g.
Obsolete Territories
Table A–19 contains territories that have been desupported as of Oracle Database 10g.
Obsolete Languages
Table A–20 contains languages that have been desupported in Oracle Database 10g.
Obsolete Character Sets and Replacement Character Sets
Table A–21 lists the obsolete character sets. If you reference any of these character sets
in your code, then replace them with the new character set.
See Also: "Choosing a Time Zone File" on page 4-15
Table A–18 Obsolete Linguistic Sorts
Obsolete Sort Name Replacement Sort
THAI_TELEPHONE THAI_M
THAI_DICTIONARY THAI_M
CANADIAN FRENCH CANADIAN_M
JAPANESE JAPANESE_M
Table A–19 Obsolete Territories
Obsolete Territory Name Replacement Territory
CIS RUSSIA
MACEDONIA FYR MACEDONIA
YUGOSLAVIA SERBIA AND MONTENEGRO
CZECHOSLOVAKIA CZECH REPUBLIC or SLOVAKIA
Table A–20 Obsolete Languages
Obsolete Language Name Replacement Language
BENGALI BANGLA
Obsolete Locale Data
A-30 Oracle Database Globalization Support Guide
Table A–21 Obsolete Character Sets and Replacements
Old Character Set Replacement Character Set
AL24UTFSS UTF8, AL32UTF8
AR8ADOS710T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8ADOS720T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8APTEC715T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8ASMO708PLUS AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8HPARABIC8T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8MUSSAD768T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8NAFITHA711T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8NAFITHA721T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8SAKHR707T AR8ISO8859P6, AR8MSWIN1256, and AL32UTF8
AR8MSAWIN AR8MSWIN1256
AR8XBASIC AR8EBCDIC420S
CL8EBCDIC875S CL8EBCDIC875R
CL8MSWINDOW31 CL8MSWIN1251
EL8EBCDIC875S EL8EBCDIC875R
JVMS JA16VMS
JEUC JA16EUC
SJIS JA16SJIS
JDBCS JA16DBCS
KSC5601 KO16KSC5601
KDBCS KO16DBCS
CGB2312-80 ZHS16CGB231280
CNS 11643-86 ZHT32EUC
JA16EUCFIXED UTF8 and AL16UTF16. See Also: the Note in this section.
ZHS32EUCFIXED UTF8 and AL16UTF16
ZHS16GBKFIXED UTF8 and AL16UTF16
JA16DBCSFIXED UTF8 and AL16UTF16
KO16DBCSFIXED UTF8 and AL16UTF16
ZHS16DBCSFIXED UTF8 and AL16UTF16
ZHS16CGB231280FIXED UTF8 and AL16UTF16
ZHT16DBCSFIXED UTF8 and AL16UTF16
KO16KSC5601FIXED UTF8 and AL16UTF16
JA16SJISFIXED UTF8 and AL16UTF16. See Also: the Note in this section.
ZHT16BIG5FIXED UTF8 and AL16UTF16
ZHT32TRISFIXED UTF8 and AL16UTF16
Obsolete Locale Data
Locale Data A-31
AL24UTFFSS Character Set Desupported
The Unicode Character Set AL24UTFFSS was desupported in Oracle9i. With Oracle
Database 10g, Oracle Database began offering the Unicode database character set
AL32UTF8, which is based on Unicode 4.0, and UTF8, which is based on Unicode 3.0.
These have been subsumed into Unicode 5.0.
The migration path for an existing AL24UTFFSS database is to upgrade to UTF8 prior
to upgrading to Oracle Database 11g. As with all migrations to a new database
character set, Oracle recommends that you use the Character Set Scanner for data
analysis before attempting to migrate your existing database character set to UTF8.
Updates to the Oracle Database Language and Territory Definition Files
Changes have been made to the content in some of the language and territory
definition files in Oracle Database 11g. These updates are necessary to correct the
legacy definitions that no longer meet the local conventions in some of the languages
and territories that Oracle Database supports. These changes include modifications to
the currency symbols, month names, and group separators. One example is the local
currency symbol for Brazil. This was updated from Cr$ to R$ in Oracle Database 10g.
Please refer to the "Oracle Database Language and Territory Definition Changes" table
documented in the $ORACLE_HOME/nls/data/old/data_changes.html file for a
detailed list of the changes.
Oracle Database 11g customers should review their existing application code to make
sure that the correct cultural conventions, which were introduced and defined in
Oracle Database 10g, are being used. For customers who may not be able to make the
necessary code changes to support their applications, Oracle Database offers Oracle9i
locale definition files with this release of Oracle Database.
To revert back to the Oracle9i language and territory behavior:
1. Shutdown the database.
2. Run the script cr9idata.pl from the $ORACLE_HOME/nls/data/old
directory.
Note: The character sets JA16EUCFIXED (1830) and
JA16SJISFIXED (1832) are supported on the database client side as
follows:
■when specified in the NLS_NCHAR client environment variable,
■in the ncharset (last) parameter of the OCIEnvNlsCreate() call,
■or as a value of the OCI_ATTR_CHARSET_ID attribute of a bind or
a define handle.
Note: AL24UTFFSS was introduced in Oracle Database version 7 as
the Unicode character set to support the UTF-8 encoding scheme,
which was based on the Unicode standard 1.1, and which is now
obsolete.
See Also: Chapter 12, "Character Set Scanner Utilities"
Obsolete Locale Data
A-32 Oracle Database Globalization Support Guide
3. Set the ORA_NLS10 environment variable to the newly created $ORACLE_
HOME/nls/data/9idata directory.
4. Restart the database.
Steps 2 and 3 will need to be repeated for all Oracle Database 11g clients that need to
revert back to the Oracle9i definition files.
Oracle strongly recommends that customers use Oracle Database 11g or Oracle
Database 10g locale definition files. Oracle9i locale definition files will be desupported
in a future release.
Unicode Character Code Assignments B-1
B
Unicode Character Code Assignments
This appendix offers an introduction to Unicode character assignments. This appendix
contains these topics:
■Unicode Code Ranges
■UTF-16 Encoding
■UTF-8 Encoding
Unicode Code Ranges
Table B–1 contains code ranges that have been allocated in Unicode for UTF-16
character codes.
Table B–2 contains code ranges that have been allocated in Unicode for UTF-8
character codes.
Table B–1 Unicode Character Code Ranges for UTF-16 Character Codes
Types of Characters First 16 Bits Second 16 Bits
ASCII 0000-007F -
European (except ASCII), Arabic, Hebrew 0080-07FF -
Iindic, Thai, certain symbols (such as the euro symbol), Chinese, Japanese,
Korean 0800-0FFF
1000 - CFFF
D000 - D7FF
F900 - FFFF
-
Private Use Area #1 E000 - EFFF
F000 - F8FF
-
Supplementary characters: Additional Chinese, Japanese, and Korean
characters; historic characters; musical symbols; mathematical symbols D800 - D8BF
D8CO - DABF
DAC0 - DB7F
DC00 - DFFF
DC00 - DFFF
DC00 - DFFF
Private Use Area #2 DB80 - DBBF
DBC0 - DBFF
DC00 - DFFF
DC00 - DFFF
UTF-16 Encoding
B-2 Oracle Database Globalization Support Guide
UTF-16 Encoding
As shown in Table B–1, UTF-16 character codes for some characters (Additional
Chinese/Japanese/Korean characters and Private Use Area #2) are represented in two
units of 16-bits. These are supplementary characters. A supplementary character
consists of two 16-bit values. The first 16-bit value is encoded in the range from
0xD800 to 0xDBFF. The second 16-bit value is encoded in the range from 0xDC00 to
0xDFFF. With supplementary characters, UTF-16 character codes can represent more
than one million characters. Without supplementary characters, only 65,536 characters
can be represented. The AL16UTF16 character set in Oracle Database supports
supplementary characters.
UTF-8 Encoding
The UTF-8 character codes in Table B–2 show that the following conditions are true:
■ASCII characters use 1 byte
■European (except ASCII), Arabic, and Hebrew characters require 2 bytes
■Indic, Thai, Chinese, Japanese, and Korean characters as well as certain symbols
such as the euro symbol require 3 bytes
■Characters in the Private Use Area #1 require 3 bytes
■Supplementary characters require 4 bytes
■Characters in the Private Use Area #2 require 4 bytes
Table B–2 Unicode Character Code Ranges for UTF-8 Character Codes
Types of Characters First Byte Second Byte Third Byte Fourth Byte
ASCII 00 - 7F - - -
European (except ASCII), Arabic, Hebrew C2 - DF 80 - BF - -
Indic, Thai, certain symbols (such as the
euro symbol), Chinese, Japanese, Korean E0
E1 - EC
ED
EF
A0 - BF
80 - BF
80 - 9F
A4 - BF
80 - BF
80 - BF
80 - BF
80 - BF
-
Private Use Area #1 EE
EF
80 - BF
80 - A3
80 - BF
80 - BF
-
Supplementary characters: Additional
Chinese, Japanese, and Korean characters;
historic characters; musical symbols;
mathematical symbols
F0
F1 - F2
F3
90 - BF
80 - BF
80 - AF
80 - BF
80 - BF
80 - BF
80 - BF
80 - BF
80 - BF
Private Use Area #2 F3
F4
B0 - BF
80 - 8F
80 - BF
80 - BF
80 - BF
80 - BF
Note: Blank spaces represent nonapplicable code assignments.
Character codes are shown in hexadecimal representation.
See Also: "Supplementary Characters" on page 6-2
UTF-8 Encoding
Unicode Character Code Assignments B-3
In Oracle Database, the AL32UTF8 character set supports 1-byte, 2-byte, 3-byte, and
4-byte values. In Oracle Database, the UTF8 character set supports 1-byte, 2-byte, and
3-byte values, but not 4-byte values.
UTF-8 Encoding
B-4 Oracle Database Globalization Support Guide
Glossary-1
Glossary
accent
A mark that changes the sound of a character. Because the common meaning of accent
is associated with the stress or prominence of the character's sound, the preferred
word in Oracle Database Globalization Support Guide is diacritic.
See also diacritic.
accent-insensitive linguistic sort
A linguistic sort that uses information only about base letters, not diacritics or case.
See also linguistic sort, base letter, diacritic, case.
AL16UTF16
The default Oracle Database character set for the SQL NCHAR data type, which is used
for the national character set. It encodes Unicode data in the UTF-16 encoding.
See also national character set.
AL32UTF8
An Oracle Database character set for the SQL CHAR data type, which is used for the
database character set. It encodes Unicode data in the UTF-8 encoding.
See also database character set.
ASCII
American Standard Code for Information Interchange. A common encoded 7-bit
character set for English. ASCII includes the letters A-Z and a-z, as well as digits,
punctuation symbols, and control characters. The Oracle Database character set name
is US7ASCII.
base letter
A character without diacritics. For example, the base letter for a, A, ä, and Ä is a.
See also diacritic.
binary sorting
Ordering character strings based on their binary coded values.
byte semantics
Treatment of strings as a sequence of bytes.
See also character semantics and length semantics.
Glossary-2
canonical equivalence
A basic equivalence between characters or sequences of characters. For example, ç is
equivalent to the combination of c and ,. They cannot be distinguished when they are
correctly rendered.
case
Refers to the condition of being uppercase or lowercase. For example, in a Latin
alphabet, A is the uppercase glyph for a, the lowercase glyph.
case conversion
Changing a character from uppercase to lowercase or vice versa.
case-insensitive linguistic sort
A linguistic sort that uses information about base letters and diacritics but not case.
See also base letter, case, diacritic, linguistic sort.
character
A character is an abstract element of text. A character is different from a glyph, which
is a specific representation of a character. For example, the first character of the English
upper-case alphabet can be displayed as A, A, A, and so on. These forms are different
glyphs that represent the same character. A character, a character code, and a glyph are
related as follows:
character --(encoding)--> character code --(font)--> glyph
For example, the first character of the English uppercase alphabet is represented in
computer memory as a number. The number is called the encoding or the character
code. The character code for the first character of the English uppercase alphabet is
0x41 in the ASCII encoding scheme. The character code is 0xc1 in the EBCDIC
encoding scheme.
You must choose a font to display or print the character. The available fonts depend on
which encoding scheme is being used. The character can be printed or displayed as A,
A, or A, for example. The forms are different glyphs that represent the same character.
See also character code and glyph.
character classification
Information provides details about the type of character associated with each character
code. For example, a character can be uppercase, lowercase, punctuation, or control
character.
character code
A character code is a number that represents a specific character. The number depends
on the encoding scheme. For example, the character code of the first character of the
English uppercase alphabet is 0x41 in the ASCII encoding scheme, but it is 0xc1 in the
EBCDIC encoding scheme.
See also character.
character encoding scheme
A rule that assigns numbers (character codes) to all characters in a character set.
Encoding scheme, encoding method, and encoding also mean character encoding
scheme.
Glossary-3
character repertoire
The characters that are available to be used, or encoded, for a specific character set.
character semantics
Treatment of strings as a sequence of characters.
See also byte semantics and length semantics.
character set
A collection of elements that represent textual information for a specific language or
group of languages. One language can be represented by more than one character set.
A character set does not always imply a specific character encoding scheme. A
character encoding scheme is the assignment of a character code to each character in a
character set.
In this manual, a character set usually does imply a specific character encoding
scheme. Therefore, a character set is the same as an encoded character set in this
manual.
character set migration
Changing the character set of an existing database.
character string
An ordered group of characters.
A character string can also contain no characters. In this case, the character string is
called a null string. The number of characters in a null string is 0 (zero).
client character set
The encoded character set used by the client. A client character set can differ from the
server character set. The server character set is called the database character set. If the
client character set is different from the database character set, then character set
conversion must occur.
See also database character set.
code point
The numeric representation of a character in a character set. For example, the code
point of A in the ASCII character set is 0x41. The code point of a character is also called
the encoded value of a character.
See also Unicode code point.
code unit
The unit of encoded text for processing and interchange. The size of the code unit
varies depending on the character encoding scheme. In most character encodings, a
code unit is 1 byte. Important exceptions are UTF-16 and UCS-2, which use 2-byte
code units, and wide character, which uses 4 bytes.
See also character encoding scheme.
collation
Ordering of character strings according to rules about sorting characters that are
associated with a language in a specific locale. Also called linguistic sort.
See also linguistic sort, monolingual linguistic sort, multilingual linguistic sort,
accent-insensitive linguistic sort, case-insensitive linguistic sort.
Glossary-4
data scanning
The process of identifying potential problems with character set conversion and
truncation of data before migrating the database character set.
database character set
The encoded character set that is used to store text in the database. This includes CHAR,
VARCHAR2, LONG, and fixed-width CLOB column values and all SQL and PL/SQL text.
diacritic
A mark near or through a character or combination of characters that indicates a
different sound than the sound of the character without the diacritical mark. For
example, the cedilla in façade is a diacritic. It changes the sound of c.
EBCDIC
Extended Binary Coded Decimal Interchange Code. EBCDIC is a family of encoded
character sets used mostly on IBM systems.
encoded character set
A character set with an associated character encoding scheme. An encoded character
set specifies the number (character code) that is assigned to each character.
See also character encoding scheme.
encoded value
The numeric representation of a character in a character set. For example, the code
point of A in the ASCII character set is 0x41. The encoded value of a character is also
called the code point of a character.
font
An ordered collection of character glyphs that provides a graphical representation of
characters in a character set.
globalization
The process of making software suitable for different linguistic and cultural
environments. Globalization should not be confused with localization, which is the
process of preparing software for use in one specific locale (for example, translating
error messages or user interface text from one language to another).
glyph
A glyph (font glyph) is a specific representation of a character. A character can have
many different glyphs. For example, the first character of the English uppercase
alphabet can be printed or displayed as A, A, A, and so on. These forms are different
glyphs that represent the same character.
See also character.
ideograph
A symbol that represents an idea. Chinese is an example of an ideographic writing
system.
ISO
International Organization for Standards. A worldwide federation of national
standards bodies from 130 countries. The mission of ISO is to develop and promote
standards in the world to facilitate the international exchange of goods and services.
Glossary-5
ISO 8859
A family of 8-bit encoded character sets. The most common one is ISO 8859-1 (also
known as ISO Latin1), and is used for Western European languages.
ISO 14651
A multilingual linguistic sort standard that is designed for almost all languages of the
world.
See also multilingual linguistic sort.
ISO/IEC 10646
A universal character set standard that defines the characters of most major scripts
used in the modern world. In 1993, ISO adopted Unicode version 1.1 as ISO/IEC
10646-1:1993. ISO/IEC 10646 has two formats: UCS-2 is a 2-byte fixed-width format,
and UCS-4 is a 4-byte fixed-width format. There are three levels of implementation, all
relating to support for composite characters:
■Level 1 requires no composite character support.
■Level 2 requires support for specific scripts (including most of the Unicode scripts
such as Arabic and Thai).
■Level 3 requires unrestricted support for composite characters in all languages.
ISO currency
The 3-letter abbreviation used to denote a local currency, based on the ISO 4217
standard. For example, USD represents the United States dollar.
ISO Latin1
The ISO 8859-1 character set standard. It is an 8-bit extension to ASCII that adds 128
characters that include the most common Latin characters used in Western Europe.
The Oracle Database character set name is WE8ISO8859P1.
See also ISO 8859.
length semantics
Length semantics determines how you treat the length of a character string. The length
can be treated as a sequence of characters or bytes.
See also character semantics and byte semantics.
linguistic index
An index built on a linguistic sort order.
linguistic sort
An ordering of strings based on requirements from a locale instead of the binary
representation of the strings.
See also multilingual linguistic sort and monolingual linguistic sort.
locale
A collection of information about the linguistic and cultural preferences from a
particular region. Typically, a locale consists of language, territory, character set,
linguistic, and calendar information defined in NLS data files.
Glossary-6
localization
The process of providing language-specific or culture-specific information for software
systems. Translation of an application's user interface is an example of localization.
Localization should not be confused with globalization, which is the making software
suitable for different linguistic and cultural environments.
monolingual linguistic sort
An Oracle Database sort that has two levels of comparison for strings. Most European
languages can be sorted with a monolingual sort, but it is inadequate for Asian
languages.
See also multilingual linguistic sort.
monolingual support
Support for only one language.
multibyte
Two or more bytes.
When character codes are assigned to all characters in a specific language or a group of
languages, one byte (8 bits) can represent 256 different characters. Two bytes (16 bits)
can represent up to 65,536 different characters. Two bytes are not enough to represent
all the characters for many languages. Some characters require 3 or 4 bytes.
One example is the UTF8 Unicode encoding. In UTF8, there are many 2-byte and
3-byte characters.
Another example is Traditional Chinese, used in Taiwan. It has more than 80,000
characters. Some character encoding schemes that are used in Taiwan use 4 bytes to
encode characters.
See also single byte.
multibyte character
A character whose character code consists of two or more bytes under a certain
character encoding scheme.
Note that the same character may have different character codes under different
encoding schemes. Oracle Database cannot tell whether a character is a multibyte
character without knowing which character encoding scheme is being used. For
example, Japanese Hankaku-Katakana (half-width Katakana) characters are one byte
in the JA16SJIS encoded character set, two bytes in JA16EUC, and three bytes in UTF8.
See also single-byte character.
multibyte character string
A character string that consists of one of the following strings:
■No characters (called a null string)
■One or more single-byte characters
■A mixture of one or more single-byte characters and one or more multibyte
characters
■One or more multibyte characters
Glossary-7
multilingual linguistic sort
An Oracle Database sort that evaluates strings on three levels. Asian languages require
a multilingual linguistic sort even if data exists in only one language. Multilingual
linguistic sorts are also used when data exists in several languages.
national character set
An alternate character set from the database character set that can be specified for
NCHAR, NVARCHAR2, and NCLOB columns. National character sets are in Unicode only.
NLB files
Binary files used by the Locale Builder to define locale-specific data. They define all of
the locale definitions that are shipped with a specific release of Oracle Database. You
can create user-defined NLB files with Oracle Locale Builder.
See also Oracle Locale Builder and NLT files.
NLS
National Language Support. NLS enables users to interact with the database in their
native languages. It also enables applications to run in different linguistic and cultural
environments. The term is somewhat obsolete because Oracle Database supports
multiple global users at one time.
NLSRTL
National Language Support Runtime Library. This library is responsible for providing
locale-independent algorithms for internationalization. The locale-specific information
(that is, NLSDATA) is read by the NLSRTL library during run-time.
NLT files
Text files used by the Locale Builder to define locale-specific data. Because they are in
text, you can view the contents.
null string
A character string that contains no characters.
Oracle Locale Builder
A GUI utility that offers a way to view, modify, or define locale-specific data. You can
also create your own formats for language, territory, character set, and linguistic sort.
replacement character
A character used during character conversion when the source character is not
available in the target character set. For example, ? (question mark) is often used as the
default replacement character for Oracle Database.
restricted multilingual support
Multilingual support that is restricted to a group of related languages.Western
European languages can be represented with ISO 8859-1, for example. If multilingual
support is restricted, then Thai could not be added to the group.
SQL CHAR datatypes
Includes CHAR, VARCHAR, VARCHAR2, CLOB, and LONG datatypes.
SQL NCHAR datatypes
Includes NCHAR, NVARCHAR, NVARCHAR2, and NCLOB datatypes.
Glossary-8
script
A particular system of writing. A collection of related graphic symbols that are used in
a writing system. Some scripts can represent multiple languages, and some languages
use multiple scripts. Examples of scripts include Latin, Arabic, and Han.
single byte
One byte. One byte usually consists of 8 bits. When character codes are assigned to all
characters for a specific language, one byte (8 bits) can represent 256 different
characters.
See also multibyte.
single-byte character
A single-byte character is a character whose character code consists of one byte under
a specific character encoding scheme. Note that the same character may have different
character codes under different encoding schemes. Oracle Database cannot tell which
character is a single-byte character without knowing which encoding scheme is being
used. For example, the euro currency symbol is one byte in the WE8MSWIN1252
encoded character set, two bytes in AL16UTF16, and three bytes in UTF8.
See also multibyte character.
single-byte character string
A single-byte character string consists of one of the following strings:
■No character (called a null string)
■One or more single-byte characters
supplementary characters
The first version of Unicode was a 16-bit, fixed-width encoding that used two bytes to
encode each character. This enabled 65,536 characters to be represented. However,
more characters need to be supported because of the large number of Asian
ideograms.
Unicode 3.1 defined supplementary characters to meet this need. Unicode 3.1 began
using two 16-bit code units (also known as surrogate pairs) to represent a single
character. This enabled an additional 1,048,576 characters to be defined. The Unicode
3.1 standard added the first group of 44,944 supplementary characters. More were
added with Unicode 4.0 versions, and 1,369 more have been added with Unicode 5.0.
surrogate pairs
See also supplementary characters.
syllabary
Provide a mechanism for communicating phonetic information along with the
ideographic characters used by languages such as Japanese.
UCS-2
A 1993 ISO/IEC standard character set. It is a fixed-width, 16-bit Unicode character
set. Each character occupies 16 bits of storage. The ISO Latin1 characters are the first
256 code points, so it can be viewed as a 16-bit extension of ISO Latin1.
Glossary-9
UCS-4
A fixed-width, 32-bit Unicode character set. Each character occupies 32 bits of storage.
The UCS-2 characters are the first 65,536 code points in this standard, so it can be
viewed as a 32-bit extension of UCS-2. This is also sometimes referred to as ISO-10646.
Unicode
Unicode is a universal encoded character set that enables information from any
language to be stored by using a single character set. Unicode provides a unique code
value for every character, regardless of the platform, program, or language.
Unicode database
A database whose database character set is UTF-8.
Unicode code point
A value in the Unicode codespace, which ranges from 0 to 0x10FFFF. Unicode assigns
a unique code point to every character.
Unicode datatype
A SQL NCHAR datatype (NCHAR, NVARCHAR2, and NCLOB). You can store Unicode
characters in columns of these datatypes even if the database character set is not
Unicode.
unrestricted multilingual support
The ability to use as many languages as desired. A universal character set, such as
Unicode, helps to provide unrestricted multilingual support because it supports a very
large character repertoire, encompassing most modern languages of the world.
UTFE
A Unicode 5.0 UTF-8 Oracle Database character set with 6-byte supplementary
character support. It is used only on EBCDIC platforms.
UTF8
The UTF8 Oracle Database character set encodes characters in one, two, or three bytes.
It is for ASCII-based platforms. The UTF8 character set supports Unicode 5.0 and it is
compliant to the CESU-8 standard. Although specific supplementary characters were
not assigned code points in Unicode until version 3.1, the code point range was
allocated for supplementary characters in Unicode 3.0. Supplementary characters are
treated as two separate, user-defined characters that occupy 6 bytes.
UTF-8
The 8-bit encoding of Unicode. It is a variable-width encoding. One Unicode character
can be 1 byte, 2 bytes, 3 bytes, or 4 bytes in UTF-8 encoding. Characters from the
European scripts are represented in either 1 or 2 bytes. Characters from most Asian
scripts are represented in 3 bytes. Supplementary characters are represented in 4 bytes.
The Oracle Database character set that supports UTF-8 is AL32UTF8.
UTF-16
The 16-bit encoding of Unicode. It is an extension of UCS-2 and supports the
supplementary characters defined in Unicode by using a pair of UCS-2 code points.
One Unicode character can be 2 bytes or 4 bytes in UTF-16 encoding. Characters
(including ASCII characters) from European scripts and most Asian scripts are
represented in 2 bytes. Supplementary characters are represented in 4 bytes. The
Oracle Database character set that supports UTF-16 is AL16UTF16.
Glossary-10
wide character
A fixed-width character format that is useful for extensive text processing because it
enables data to be processed in consistent, fixed-width chunks. Wide characters are
intended to support internal character processing.
Index-1
Index
Symbols
$ORACLE_HOME/nls/data directory, 1-2
$ORACLE_HOME/oracore/zoneinfo/timezlrg.dat
time zone file, 4-15
$ORACLE_HOME/oracore/zoneinfo/timezone.dat
time zone file, 4-15
Numerics
7-bit encoding schemes, 2-7
8-bit encoding schemes, 2-7
A
abbreviations
languages, A-1
abstract datatype
creating as NCHAR, 2-14
accent, 5-9
accent-insensitive linguistic sort, 5-9
ADCS script
migrating character sets in Real Application
Clusters, 11-7
ADD_MONTHS SQL function, 4-12
ADO interface and Unicode, 7-30
AL16UTF16 character set, 6-5, A-15
AL24UTFFSS character set, 6-4
AL32UTF8 character set, 6-5, 6-6, A-15
ALTER SESSION statement
SET NLS_CURRENCY clause, 3-26, 3-27
SET NLS_LANGUAGE clause, 3-13
SET NLS_NUMERIC_CHARACTERS
clause, 3-24
SET NLS_TERRITORY clause, 3-13
ALTER TABLE MODIFY statement
migrating from CHAR to NCHAR, 11-9
analyse_histgrm.sql script, 12-34
analyse_rule.sql script, 12-34
analyse_source.sql script, 12-34
application-locales, 8-36
Arial Unicode MS font, 13-2
array parameter
Database Character Set Scanner, 12-9
ASCII encoding, 2-4
AT LOCAL clause, 4-22
AT TIME ZONE clause, 4-22
B
base letters, 5-4, 5-5
BFILE data
loading into LOBs, 9-10
binary sorts, 5-2
case-insensitive and accent-insensitive, 5-11
example, 5-12
binding and defining CLOB and NCLOB data in
OCI, 7-17
binding and defining SQL CHAR datatypes in
OCI, 7-14
binding and defining SQL NCHAR datatypes in
OCI, 7-15
BLANK_TRIMMING parameter, 11-3
BLOBs
creating indexes, 6-17
boundaries parameter
Database Character Set Scanner, 12-10
byte semantics, 2-8, 3-31
C
C number format mask, 3-26
Calendar Utility, 13-15
calendars
customizing, 13-15
parameter, 3-19
supported, A-22
canonical equivalence, 5-3, 5-7
capture parameter
Database Character Set Scanner, 12-10
case, 5-1
case-insensitive linguistic sort, 5-9
CESU-8 compliance, A-16
CHAR columns
migrating to NCHAR columns, 11-9
character data
converting with CONVERT SQL function, 9-4
character data conversion
database character set, 11-6
character data scanning
before character set migration, 11-6
character rearrangement, 5-8
Index-2
character repertoire, 2-2
character semantics, 2-8, 3-31
character set
conversion, 13-21
data loss
during conversion, 2-12
detecting with Globalization Development
Kit, 8-32
national, 7-4
character set conversion
between OCI client and database server, 7-12
parameters, 3-31
character set definition
customizing, 13-23
guidelines for editing files, 13-22
naming files, 13-22
character set migration
CSALTER script, 11-6
identifying character data conversion
problems, 11-6
postmigration tasks, 11-11
scanning character data, 11-6
character sets
AL16UTF16, 6-5
AL24UTFFSS, 6-4
AL32UTF8, 6-5
Asian, A-6, A-7
changing after database creation, 2-15
choosing, 11-1
choosing a character set for a Unicode
database, 6-9
choosing a national character set, 6-10
conversion, 2-12, 2-16, 9-4
conversion using OCI, 10-5
customizing, 13-20
data loss, 11-3
encoding, 2-1
European, A-8, A-11
ISO 8859 series, 2-5
Middle Eastern, A-14
migrating and the data dictionary, 12-33
migration, 11-1, 11-2
naming, 2-8
national, 6-7, 7-4
restrictions on character sets used to express
names, 2-12
supersets and subsets, A-16
supported, A-5
supporting different character repertoires, 2-3
universal, A-15
UTFE, 6-5
character snational, 2-14
character type conversion
error reporting, 3-31
characters
available in all Oracle database character sets, 2-3
context-sensitive, 5-6
contracting, 5-6
user-defined, 13-20
choosing a character set, 11-1
choosing between a Unicode database and Unicode
datatypes, 6-8
client operating system
character set compatibility with
applications, 2-11
CLOB and NCLOB data
binding and defining in OCI, 7-17
CLOBs
creating indexes, 6-17
code chart
displaying and printing, 13-16
code point, 2-2
collation
customizing, 13-26
column parameter
Database Character Set Scanner, 12-10
compatibility
client operating system and application character
sets, 2-11
composed characters, 5-6
context-sensitive characters, 5-6
contracting characters, 5-6
contracting letters, 5-8
control characters, encoding, 2-3
conversion
between character set ID number and character set
name, 9-6
CONVERT SQL function, 9-4
character sets, A-16
convert time zones, 4-23
convertible data
data dictionary, 12-33
converting character data
CONVERT SQL function, 9-4
converting character data between character
sets, 9-4
Coordinated Universal Time, 4-4, 4-5
creating a database with Unicode datatypes, 6-7
creating a Unicode database, 6-6
CSALTER script, 11-6, 11-7
checking phase, 12-38
running, 12-37
updating phase, 12-39
CSM$COLUMNS table, 12-35
CSM$ERRORS table, 12-36
CSM$TABLES table, 12-35
CSMIG user, 12-7
csminst.sql script
running, 12-7
CSMV$COLUMNS view, 12-40
CSMV$CONSTRAINTS view, 12-40
CSMV$ERROR view, 12-41
CSMV$INDEXES view, 12-41
CSMV$TABLES view, 12-41
currencies
formats, 3-25
CURRENT_DATE SQL function, 4-12
CURRENT_TIMESTAMP SQL function, 4-12
customizing time zone data, 13-15
Index-3
D
data conversion
in Pro*C/C++, 7-18
OCI driver, 7-23
ODBC and OLE DB drivers, 7-28
thin driver, 7-23
Unicode Java strings, 7-23
data dictionary
changing character sets, 12-33
convertible or lossy data, 12-33
data dictionary views
NLS_DATABASE_PARAMETERS, 3-8
NLS_INSTANCE_PARAMETERS, 3-8
NLS_SESSION_PARAMETER, 3-8
data expansion
during character set migration, 11-2
during data conversion, 7-13
data inconsistencies causing data loss, 11-4
data loss
caused by data inconsistencies, 11-4
during character set conversion, 2-12
during character set migration, 11-3
during datatype conversion
exceptions, 7-5
during OCI Unicode character set
conversion, 7-12
from mixed character sets, 11-5
Data Pump PL/SQL packages and character set
migration, 11-5
data truncation, 11-1
restrictions, 11-2
database character set
character data conversion, 11-6
choosing, 2-10
compatibility between client operating system and
applications, 2-11
performance, 2-12
Database Character Set Scanner, 12-12
analyse_histgrm.sql script, 12-34
analyse_rule.sql script, 12-34
analyse_source.sql script, 12-34
array parameter, 12-9
boundaries parameter, 12-10
capture parameter, 12-10
column parameter, 12-10
CSM$COLUMNS table, 12-35
CSM$ERRORS table, 12-36
CSM$TABLES table, 12-35
CSMV$COLUMNS view, 12-40
CSMV$CONSTRAINTS view, 12-40
CSMV$ERROR view, 12-41
CSMV$INDEXES view, 12-41
CSMV$TABLES view, 12-41
Database Scan Summary Report, 12-22
error messages, 12-42
exclude parameter, 12-11
feedback parameter, 12-11
fromnchar parameter, 12-12
full parameter, 12-12
help parameter, 12-12
Individual Exception Report, 12-31
invoking, 12-7
lastrpt parameter, 12-13, 12-14
maxblocks parameter, 12-14
online help, 12-8
performance, 12-36
preserve parameter, 12-15
query parameter, 12-15
restrictions, 12-37
scan modes, 12-6
suppress parameter, 12-16
table parameter, 12-16
tochar parameter, 12-16
user parameter, 12-17
userid parameter, 12-17
utility, 12-5
views, 12-39
Database Scan Summary Report, 12-22
database schemas
designing for multiple languages, 6-13
database time zone, 4-21
datatype conversion
data loss and exceptions, 7-5
implicit, 7-6
SQL functions, 7-7
datatypes
abstract, 2-14
DATE, 4-2
datetime, 4-1
inserting values into datetime datatypes, 4-5
inserting values into interval datatypes, 4-10
interval, 4-1, 4-9
INTERVAL DAY TO SECOND, 4-10
INTERVAL YEAR TO MONTH, 4-9
supported, 2-14
TIMESTAMP, 4-3
TIMESTAMP WITH LOCAL TIME ZONE, 4-5
TIMESTAMP WITH TIME ZONE, 4-4
date and time parameters, 3-15
DATE datatype, 4-2
date formats, 3-15, 9-9
and partition bound expressions, 3-16
dates
ISO standard, 3-20, 9-10
NLS_DATE_LANGUAGE parameter, 3-17
datetime datatypes, 4-1
inserting values, 4-5
datetime format parameters, 4-13
Daylight Saving Time
Oracle support, 4-23
daylight saving time session parameter, 4-14
days
format element, 3-17
language of names, 3-17
DB_TZ database time zone, 4-22
DBMS_LOB PL/SQL package, 9-10
DBMS_LOB.LOADBLOBFROMFILE
procedure, 9-11
DBMS_LOB.LOADCLOBFROMFILE
procedure, 9-11
Index-4
DBMS_REDEFINITION.CAN_REDEF_TABLE
procedure, 11-10
DBTIMEZONE SQL function, 4-12
dest_char_set parameter, A-16
detecting language and character sets
Globalization Development Kit, 8-32
detection
supported languages and character sets, A-18
diacritic, 5-1
dynamic performance views
V$NLS_PARAMETERS, 3-8
V$NLS_VALID_VALUES, 3-8
E
encoding
control characters, 2-3
ideographic writing systems, 2-3
numbers, 2-3
phonetic writing systems, 2-3
punctuation, 2-3
symbols, 2-3
encoding schemes
7-bit, 2-7
8-bit, 2-7
fixed-width, 2-7
multibyte, 2-7
shift-sensitive variable-width, 2-8
shift-sensitive variable-width multibyte, 2-8
single-byte, 2-7
variable-width, 2-7
environment variables
ORA_SDTZ, 4-14, 4-21
ORA_TZFILE, 4-14
error messages
languages, A-3
translation, A-3
ERROR_ON_OVERLAP_TIME session
parameter, 4-14
euro
Oracle support, 3-27
exclude parameter
Database Character Set Scanner, 12-11
expanding characters, 5-8
characters
expanding, 5-6
EXTRACT (datetime) SQL function, 4-12
F
feedback parameter
Database Character Set Scanner, 12-11
fixed-width multibyte encoding schemes, 2-7
fonts
Unicode, 13-2
Unicode for UNIX, 13-2
Unicode for Windows, 13-2
format elements, 9-10
C, 9-10
D, 9-10
day, 3-17
G, 9-10
IW, 9-10
IY, 9-10
L, 9-10
month, 3-17
RM, 9-9
RN, 9-10
format masks, 3-23, 9-9
formats
currency, 3-25
date, 3-15, 4-14
numeric, 3-23
time, 3-17
FROM_TZ SQL function, 4-12
fromchar parameter, 12-12
Database Character Set Scanner, 12-12
fromnchar parameter
Database Character Set Scanner, 12-12
full parameter
Database Character Set Scanner, 12-12
G
GDK
application configuration file, 8-18
GDK application configuration file, 8-35
example, 8-40
GDK application framework for J2EE, 8-16
GDK components, 8-7
GDK error messages, 8-43
GDK Java API, 8-27
GDK Java supplied packages and classes, 8-41
GDK Localizer object, 8-21
gdkapp.xml application configuration file, 8-35
gdkapp.xml GDK application configuration
file, 8-18
getString() method, 7-25
getStringWithReplacement() method, 7-25
Globalization Development Kit, 8-1
application configuration file, 8-35
character set conversion, 8-29
components, 8-7
defining supported application locales, 8-22
e-mail programs, 8-34
error messages, 8-43
framework, 8-16
integrating locale sources, 8-19
Java API, 8-27
Java supplied packages and classes, 8-41
locale detection, 8-20
Localizer object, 8-21
managing localized content in static files, 8-26
managing strings in JSPs and Java servlets, 8-25
non_ASCII input and output in an HTML
page, 8-23
Oracle binary and linguistic sorts, 8-31
Oracle date, number, and monetary formats, 8-30
Oracle language and character set detection, 8-32
Oracle locale information, 8-28
Index-5
Oracle locale mapping, 8-28
Oracle translated locale and time zone
names, 8-33
supported locale resources, 8-19
globalization features, 1-4
globalization support
architecture, 1-1
Greenwich Mean Time, 4-4, 4-5
guessing the language or character set, 12-1
H
help parameter
Database Character Set Scanner, 12-12
I
IANA character sets
mapping with ISO locales, 8-24
ideographic writing systems, encoding, 2-3
ignorable characters, 5-6
implicit datatype conversion, 7-6
indexes
creating for documents stored as CLOBs, 6-17
creating for multilingual document search, 6-16
creating indexes for documents stored as
BLOBs, 6-17
partitioned, 9-9
Individual Exception Report, 12-31
initialization parameters
NLS_DATE_FORMAT, 4-14
NLS_TIMESTAMP_FORMAT, 4-14
NLS_TIMESTAMP_TZ_FORMAT, 4-14
INSTR SQL functions, 7-8, 9-5
Internet application
locale
determination, 8-6
monolingual, 8-2
multilingual, 8-2, 8-4
interval datatypes, 4-1, 4-9
inserting values, 4-10
INTERVAL DAY TO SECOND datatype, 4-10
INTERVAL YEAR TO MONTH datatype, 4-9
ISO 8859 character sets, 2-5
ISO locales
mapping with IANA character sets, 8-24
ISO standard
date format, 9-10
ISO standard date format, 3-20, 9-10
ISO week number, 9-10
IW format element, 9-10
IY format element, 9-10
J
Java
Unicode data conversion, 7-23
Java strings
binding and defining in Unicode, 7-20
JDBC drivers
form of use argument, 7-22
JDBC OCI driver
and Unicode, 7-3
JDBC programming
Unicode, 7-20
JDBC Server Side internal driver
and Unicode, 7-3
JDBC Server Side thin driver
and Unicode, 7-3
JDBC thin driver
and Unicode, 7-3
L
language
detecting with Globalization Development
Kit, 8-32
language abbreviations, A-1
Language and Character Set File Scanner, 12-1
language definition
customizing, 13-6
overriding, 3-6
language support, 1-4
languages
error messages, A-3
languages and character sets
supported by LCSSCAN, A-18
LAST_DAY SQL function, 4-12
lastrpt parameter
Database Character Set Scanner, 12-13, 12-14
LCSCCAN
error messages, 12-4
LCSSCAN, 12-1
supported languages and character sets, 12-4,
A-18
LCSSCAN command
BEGIN parameter, 12-2
END parameter, 12-3
examples, 12-3
FILE parameter, 12-3
HELP parameter, 12-4
online help, 12-4
RESULTS parameter, 12-2
syntax, 12-2
length semantics, 2-8, 3-31
LENGTH SQL functions, 9-5
LIKE conditions in SQL statements, 9-6
LIKE2 SQL condition, 9-6
LIKE4 SQL condition, 9-6
LIKEC SQL condition, 9-6
linguistic sort definitions
supported, A-19
linguistic sorts
accent-insensitive, 5-9
BINARY, 5-11
BINARY_AI, linguistic sorts
BINARY_CI, 5-11
case-insensitive, 5-9
controlling, 9-9
customizing, 13-26
characters with diacritics, 13-29, 13-31
Index-6
levels, 5-4
list of defaults, A-2
parameters, 3-29
list parameter, 3-22
lmsgen utility, 10-6
loading external BFILE data into LOBs, 9-10
LOBs
loading external BFILE data, 9-10
storing documents in multiple languages, 6-15
locale, 3-3
dependencies, 3-6
detection
Globalization Development Kit, 8-20
of Internet application
determining, 8-6
variant, 3-6
locale information
mapping between Oracle and other
standards, 10-3
locale-charset-map, 8-35
locale-determine-rule, 8-37
LocaleMapper class, 8-34
locale-parameter-name, 8-38
LOCALTIMESTAMP SQL function, 4-13
lossy data
data dictionary, 12-33
lxegen utility, 13-16
M
maxblocks parameter
Database Character Set Scanner, 12-14
message-bundles, 8-38
migrating a character set
CSALTER script, 11-6
migrating character sets in Real Application
Clusters, 11-7
migration
CHAR columns to NCHAR columns, 11-9
character sets, 11-1
to NCHAR datatypes, 11-8
version 8 NCHAR columns to Oracle9i and
later, 11-8
mixed character sets
causing data loss, 11-5
monetary parameters, 3-24
monolingual Internet application, 8-2
monolingual linguistic sorts
example, 5-12
supported, A-20
months
format element, 3-17
language of names, 3-17
MONTHS_BETWEEN SQL function, 4-12
multibyte encoding schemes, 2-7
fixed-width, 2-7
shift-sensitive variable-width, 2-8
variable-width, 2-7
multilexers
creating, 6-16
multilingual data
specifying column lengths, 6-13
multilingual document search
creating indexes, 6-16
multilingual Internet application, 8-4
multilingual linguistic sorts
example, 5-13
supported, A-21
multilingual support
restricted, 2-18
unrestricted, 2-18
multiple languages
designing database schemas, 6-13
storing data, 6-14
storing documents in LOBs, 6-15
N
N SQL function, 7-7
national character set, 2-14, 6-7, 7-4
NCHAR columns
migrating from version 8 to Oracle9i and
later, 11-8
NCHAR datatype, 7-4
creating abstract datatype, 2-14
migrating, 11-8
migration, 11-8
NCHR SQL function, 7-9
NCLOB datatype, 7-5
NEW_TIME SQL function, 4-12
NEXT_DAY SQL function, 4-12
NLB data
transportable, 13-35
NLB file, 13-4
NLB files, 13-1
generating and installing, 13-33
NLS Calendar Utility, 13-15
NLS parameters
default values in SQL functions, 9-2
list, 3-2
setting, 3-1
specifying in SQL functions, 9-2
unacceptable in SQL functions, 9-3
NLS Runtime Library, 1-1
NLS_CALENDAR parameter, 3-22
NLS_CHARSET_DECL_LEN SQL function, 9-7
NLS_CHARSET_ID SQL function, 9-6
NLS_CHARSET_NAME SQL function, 9-6
NLS_COMP parameter, 3-30, 9-8
NLS_CREDIT parameter, 3-28
NLS_CURRENCY parameter, 3-25
NLS_DATABASE_PARAMETERS data dictionary
view, 3-8
NLS_DATE_FORMAT initialization parameter, 4-14
NLS_DATE_FORMAT parameter, 3-15
NLS_DATE_LANGUAGE parameter, 3-16
NLS_DEBIT parameter, 3-29
NLS_DUAL_CURRENCY parameter, 3-27
NLS_INITCAP SQL function, 5-8, 9-1
NLS_INSTANCE_PARAMETERS data dictionary
Index-7
view, 3-8
NLS_ISO_CURRENCY parameter, 3-26
NLS_LANG parameter, 3-3
choosing a locale, 3-3
client setting, 3-7
examples, 3-5
OCI client applications, 7-14
specifying, 3-5
UNIX client, 3-7
Windows client, 3-7
NLS_LANGUAGE parameter, 3-9
NLS_LENGTH_SEMANTICS parameter, 2-9
NLS_LIST_SEPARATOR parameter, 3-31
NLS_LOWER SQL function, 5-8, 5-9, 9-1
NLS_MONETARY_CHARACTERS parameter, 3-28
NLS_NCHAR_CONV_EXCP parameter, 3-31
NLS_NUMERIC_CHARACTERS parameter, 3-23
NLS_SESSION_PARAMETERS data dictionary
view, 3-8
NLS_SORT parameter, 3-29, 5-19
NLS_TERRITORY parameter, 3-11
NLS_TIMESTAMP_FORMAT initialization
parameter, 4-14
NLS_TIMESTAMP_FORMAT parameter
parameters
NLS_TIMESTAMP_FORMAT, 3-18, 3-19
NLS_TIMESTAMP_TZ_FORMAT initialization
parameter, 4-14
NLS_UPPER SQL function, 5-8, 5-9, 9-1
NLSRTL, 1-1
NLSSORT SQL function, 9-1, 9-7
syntax, 9-8
NLT files, 13-1
numbers, encoding, 2-3
numeric formats, 3-23
SQL masks, 9-10
numeric parameters, 3-22
NUMTODSINTERVAL SQL function, 4-13
NUMTOYMINTERVAL SQL function, 4-13
NVARCHAR datatype
Pro*C/C++, 7-19
NVARCHAR2 datatype, 7-4
O
obsolete locale data, A-29
OCI
binding and defining CLOB and NCLOB data in
OCI, 7-17
binding and defining SQL NCHAR
datatypes, 7-15
setting the character set, 10-2
SQL CHAR datatypes, 7-14
OCI and Unicode, 7-2
OCI character set conversion, 7-12
data loss, 7-12
performance, 7-12
OCI client applications
using Unicode character sets, 7-14
OCI data conversion
data expansion, 7-13
OCI_ATTR_CHARSET_FORM attribute, 7-12
OCI_ATTR_MAXDATA_SIZE attribute, 7-13
OCI_UTF16ID character set ID, 7-10
OCIBind() function, 7-14
OCICharSetConversionIsReplacementUsed(), 10-5
OCICharSetConvert(), 10-5
OCICharsetToUnicode(), 10-5
OCIDefine() function, 7-14
OCIEnvNlsCreate(), 7-10, 10-2
OCILobRead() function, 7-17
OCILobWrite() function, 7-17
OCIMessageClose(), 10-6
OCIMessageGet(), 10-6
OCIMessageOpen(), 10-6
OCIMultiByteInSizeToWideChar(), 10-4
OCIMultiByteStrCaseConversion(), 10-5
OCIMultiByteStrcat(), 10-4
OCIMultiByteStrcmp(), 10-4
OCIMultiByteStrcpy(), 10-4
OCIMultiByteStrlen(), 10-5
OCIMultiByteStrncat(), 10-4
OCIMultiByteStrncmp(), 10-4
OCIMultiByteStrncpy(), 10-4
OCIMultiByteStrnDisplayLength(), 10-5
OCIMultiByteToWideChar(), 10-4
OCINlsCharSetIdToName(), 10-3
OCINlsCharSetNameTold(), 10-2
OCINlsEnvironmentVariableGet(), 10-3
OCINlsGetInfo(), 10-2
OCINlsNameMap(), 10-3
OCINlsNumericInfoGet(), 10-3
OCIUnicodeToCharset(), 10-5
OCIWideCharDisplayLength(), 10-4
OCIWideCharInSizeToMultiByte(), 10-4
OCIWideCharIsAlnum(), 10-5
OCIWideCharIsAlpha(), 10-5
OCIWideCharIsCntrl(), 10-5
OCIWideCharIsDigit(), 10-5
OCIWideCharIsGraph(), 10-5
OCIWideCharIsLower(), 10-5
OCIWideCharIsPrint(), 10-5
OCIWideCharIsPunct(), 10-5
OCIWideCharIsSingleByte(), 10-5
OCIWideCharIsSpace(), 10-5
OCIWideCharIsUpper(), 10-5
OCIWideCharIsXdigit(), 10-5
OCIWideCharMultibyteLength(), 10-4
OCIWideCharStrCaseConversion(), 10-4
OCIWideCharStrcat(), 10-4
OCIWideCharStrchr(), 10-4
OCIWideCharStrcmp(), 10-4
OCIWideCharStrcpy(), 10-4
OCIWideCharStrlen(), 10-4
OCIWideCharStrncat(), 10-4
OCIWideCharStrncmp(), 10-4
OCIWideCharStrncpy(), 10-4
OCIWideCharStrrchr(), 10-4
OCIWideCharToLower(), 10-4
OCIWideCharToMultiByte(), 10-4
Index-8
OCIWideCharToUpper(), 10-4
ODBC Unicode applications, 7-29
OLE DB Unicode datatypes, 7-30
online table redefinition
migrating from CHAR to NCHAR, 11-9, 11-10
operating system
character set compatibility with
applications, 2-11
ORA_NLS10 environment variable, 1-2
ORA_SDTZ environment variable, 4-14, 4-21
ORA_TZFILE environment variable, 4-14
Oracle Call Interface and Unicode, 7-2
Oracle Data Provide for .NET and Unicode, 7-3
Oracle Data Pump and character set
conversion, 11-5
Oracle Language and Character Set Detection Java
classes, 8-32
Oracle Locale Builder
choosing a calendar format, 13-10
choosing currency formats, 13-13
choosing date and time formats, 13-11
displaying code chart, 13-16
Existing Definitions dialog box, 13-4
fonts, 13-2
Open File dialog box, 13-5
Preview NLT screen, 13-4
restrictions on names for locale objects, 13-7
Session Log dialog box, 13-4
starting, 13-3
Oracle ODBC driver and Unicode, 7-2
Oracle OLE DB driver and Unicode, 7-2
Oracle Pro*C/C++ and Unicode, 7-2
oracle.i18n.lcsd package, 8-41
oracle.i18n.net package, 8-41
oracle.i18n.servlet package, 8-42
oracle.i18n.text package, 8-42
oracle.i18n.util package, 8-42
oracle.sql.CHAR class
character set conversion, 7-24
getString() method, 7-25
getStringWithReplacement() method, 7-25
toString() method, 7-25
ORDER BY clause, 9-9
OS_TZ local operating system time zone, 4-22
overriding language and territory definitions, 3-6
P
page-charset, 8-36
parameters
BLANK_TRIMMING, 11-3
calendar, 3-19
character set conversion, 3-31
linguistic sorts, 3-29
methods of setting, 3-2
monetary, 3-24
NLS_CALENDAR, 3-22
NLS_COMP, 3-30
NLS_CREDIT, 3-28
NLS_CURRENCY, 3-25
NLS_DATE_FORMAT, 3-15
NLS_DATE_LANGUAGE, 3-16
NLS_DEBIT, 3-29
NLS_DUAL_CURRENCY, 3-27
NLS_ISO_CURRENCY, 3-26
NLS_LANG, 3-3
NLS_LANGUAGE, 3-9
NLS_LIST_SEPARATOR, 3-31
NLS_MONETARY_CHARACTERS, 3-28
NLS_NCHAR_CONV_EXCP, 3-31
NLS_NUMERIC_CHARACTERS, 3-23
NLS_SORT, 3-29
NLS_TERRITORY, 3-11
numeric, 3-22
setting, 3-1
time and date, 3-15
time zone, 3-18, 3-19
partitioned
indexes, 9-9
tables, 9-9
performance
choosing a database character set, 2-12
during OCI Unicode character set
conversion, 7-12
phonetic writing systems, encoding, 2-3
PL/SQL and SQL and Unicode, 7-3
preserve parameter
Database Character Set Scanner, 12-15
primary level sort, 5-4
Private Use Area, 13-21
Pro*C/C++
data conversion, 7-18
NVARCHAR datatype, 7-19
UVARCHAR datatype, 7-19
VARCHAR datatype, 7-18
punctuation, encoding, 2-3
Q
query parameter
Database Character Set Scanner, 12-15
R
Real Application Clusters
database character set migration, 11-7
REGEXP SQL functions, 5-20
regular expressions
character class, 5-21
character range, 5-21
collation element delimiter, 5-21
equivalence class, 5-22
examples, 5-22
multilingual environment, 5-20
replacement characters
CONVERT SQL function, 9-4
restricted multilingual support, 2-17, 2-18
restrictions
data truncation, 11-2
passwords, 11-2
Index-9
space padding during export, 11-3
usernames, 11-2
reverse secondary sorting, 5-7
ROUND (date) SQL function, 4-12
RPAD SQL function, 7-8
S
scan modes
Database Character Set Scanner, 12-6
full database scan, 12-6
single table scan, 12-6
user tables scan, 12-6
scan.err file, 12-22
scan.out file, 12-18, 12-19, 12-20, 12-21
scan.txt file, 12-22
searching multilingual documents, 6-16
searching string, 5-20
secondary level sort, 5-4
session parameters
ERROR_ON_OVERLAP, 4-14
session time zone, 4-21
SESSIONTIMEZONE SQL function, 4-13
setFormOfUse() method, 7-22
shift-sensitive variable-width multibyte encoding
schemes, 2-8
single-byte encoding schemes, 2-7
sorting
reverse secondary, 5-7
specifying nondefault linguistic sorts, 3-29, 3-30
source_char_set parameter, A-16
space padding
during export, 11-3
special combination letters, 5-6, 5-8
special letters, 5-6, 5-8
special lowercase letters, 5-8
special uppercase letters, 5-8
SQL CHAR datatypes, 2-10
OCI, 7-14
SQL conditions
LIKE2, 9-6
LIKE4, 9-6
LIKEC, 9-6
SQL functions
ADD_MONTHS, 4-12
CONVERT, 9-4
CURRENT_DATE, 4-12
CURRENT_TIMESTAMP, 4-12
datatype conversion, 7-7
DBTIMEZONE, 4-12
default values for NLS parameters, 9-2
EXTRACT (datetime), 4-12
FROM_TZ, 4-12
INSTR, 7-8, 9-5
LAST_DAY, 4-12
LENGTH, 9-5
LOCALTIMESTAMP, 4-13
MONTHS_BETWEEN, 4-12
N, 7-7
NCHR, 7-9
NEW_TIME, 4-12
NEXT_DAY, 4-12
NLS_CHARSET_DECL_LEN, 9-7
NLS_CHARSET_ID, 9-6
NLS_CHARSET_NAME, 9-6
NLS_INITCAP, 5-8, 9-1
NLS_LOWER, 5-8, 5-9, 9-1
NLS_UPPER, 5-8, 5-9, 9-1
NLSSORT, 9-1, 9-7
NUMTODSINTERVAL, 4-13
NUMTOYMINTERVAL, 4-13
ROUND (date), 4-12
RPAD, 7-8
SESSIONTIMEZONE, 4-13
specifying NLS parameters, 9-2
SUBSTR, 9-5
SUBSTR2, 9-5
SUBSTR4, 9-5
SUBSTRB, 9-5
SUBSTRC, 9-5
SYS_EXTRACT_UTC, 4-13
SYSDATE, 4-13
SYSTIMESTAMP, 4-13
TO_CHAR, 9-1
TO_CHAR (datetime), 4-13
TO_DATE, 7-7, 9-1
TO_DSINTERVAL, 4-13
TO_NCHAR, 7-7
TO_NUMBER, 9-1
TO_TIMESTAMP, 4-13
TO_TIMESTAMP_TZ, 4-13
TO_YMINTERVAL, 4-13
TRUNC (date), 4-12
TZ_OFFSET, 4-13
unacceptable NLS parameters, 9-3
UNISTR, 7-9
SQL NCHAR datatypes
binding and defining in OCI, 7-15
SQL statements
LIKE conditions, 9-6
strict superset, 6-2
string comparisons
WHERE clause, 9-8
string literals
Unicode, 7-8
string manipulation using OCI, 10-3
strings
searching, 5-20
SUBSTR SQL function, 9-5
SUBSTR SQL functions, 9-5
SUBSTR, 9-5
SUBSTR2, 9-5
SUBSTR4, 9-5
SUBSTRB, 9-5
SUBSTRC, 9-5
SUBSTR4 SQL function, 9-5
SUBSTRB SQL function, 9-5
SUBSTRC SQL function, 9-5
superset, strict, 6-2
supersets and subsets, A-16
Index-10
supplementary characters, 5-3, 6-2
linguistic sort support, A-22
supported datatypes, 2-14
supported territories, A-4
suppress parameter
Database Character Set Scanner, 12-16
surrogate pairs, 6-2
syllabary, 2-3
symbols, encoding, 2-3
SYS_EXTRACT_UTC SQL function, 4-13
SYSDATE SQL function, 4-13
effect of session time zone, 4-22
SYSTIMESTAMP SQL function, 4-13
T
table parameter
Database Character Set Scanner, 12-16
tables
partitioned, 9-9
territory
dependencies, 3-6
territory definition, 3-11
customizing, 13-9
overriding, 3-6
territory support, 1-5, A-4
territory variant, 3-6
tertiary level sort, 5-4
Thai and Laotian character rearrangement, 5-8
tilde, 7-27
time and date parameters, 3-15
time zone
abbreviations, 4-15
data source, 4-15
database, 4-21
effect on SYSDATE SQL function, 4-22
environment variables, 4-14
names, 4-15
parameters, 3-18, 3-19
session, 4-21
time zone file
choosing, 4-15
default, 4-15
time zones
converting, 4-23
customizing, 13-15
upgrading definitions, 4-17
TIMESTAMP datatype, 4-3
when to use, 4-8
TIMESTAMP datatypes
choosing, 4-8
timestamp format, 3-18
TIMESTAMP WITH LOCAL TIME ZONE
datatype, 4-5
when to use, 4-8
TIMESTAMP WITH TIME ZONE datatype, 4-4
when to use, 4-8
timezlrg.dat file, 13-15
timezone.dat file, 13-15
TO_CHAR (datetime) SQL function, 4-13
TO_CHAR SQL function, 9-1
default date format, 3-15, 4-14
format masks, 9-9
group separator, 3-23
language for dates, 3-16
spelling of days and months, 3-17
TO_DATE SQL function, 7-7, 9-1
default date format, 3-15, 4-14
format masks, 9-9
language for dates, 3-16
spelling of days and months, 3-17
TO_DSINTERVAL SQL function, 4-13
TO_NCHAR SQL function, 7-7
TO_NUMBER SQL function, 9-1
format masks, 9-9
TO_TIMESTAMP SQL function, 4-13
TO_TIMESTAMP_TZ SQL function, 4-13
TO_YMINTERVAL SQL function, 4-13
tochar parameter
Database Character Set Scanner, 12-16
toString() method, 7-25
transportable NLB data, 13-35
TRUNC (date) SQL function, 4-12
TZ_OFFSET SQL function, 4-13
TZABBREV, 4-15
TZNAME, 4-15
U
UCS-2 encoding, 6-3
Unicode, 6-1
binding and defining Java strings, 7-20
character code assignments, B-1
character set conversion between OCI client and
database server, 7-12
code ranges for UTF-16 characters, B-1
code ranges for UTF-8 characters, B-1
data conversion in Java, 7-23
encoding, 6-2
fonts, 13-2
JDBC OCI driver, 7-3
JDBC programming, 7-20
JDBC Server Side internal driver, 7-3
JDBC Server Side thin driver, 7-3
JDBC thin driver, 7-3
mode, 7-10
ODBC and OLE DB programming, 7-27
Oracle Call Interface, 7-2
Oracle Data Provide for .NET, 7-3
Oracle ODBC driver, 7-2
Oracle OLE DB driver, 7-2
Oracle Pro*C/C++, 7-2
Oracle support, 6-4
parsing an XML stream with Java, 7-32
PL/SQL and SQL, 7-3
Private Use Area, 13-21
programming, 7-1
reading an XML file with Java, 7-32
string literals, 7-8
UCS-2 encoding, 6-3
Index-11
UTF-16 encoding, 6-3
UTF-8 encoding, 6-2
writing an XML file with Java, 7-31
XML programming, 7-31
Unicode database, 6-6
case study, 6-11
choosing a character set, 6-9
using with Unicode datatypes (case study), 6-12
when to use, 6-8
Unicode datatypes, 6-7
case study, 6-12
choosing a national character set, 6-10
using with a Unicode database (case study), 6-12
when to use, 6-8
UNISTR SQL function, 7-9
unrestricted multilingual support, 2-18
url-rewrite-rule, 8-39
US7ASCII
supersets, A-17
user parameter
Database Character Set Scanner, 12-17
user-defined characters, 13-20
adding to a character set definition, 13-25
cross-references between character sets, 13-22
userid parameter
Database Character Set Scanner, 12-17
UTC, 4-4, 4-5
UTF-16 encoding, 6-3, B-2
UTF8 character set, 6-6, A-15
UTF-8 encoding, 6-2, B-2
UTFE character set, 6-5, 6-6, A-15
UTL_FILE package, using with NCHAR, 7-10
UTL_I18N PL/SQL package, 8-43
UTL_LMS PL/SQL package, 8-43
utltzuv2.sql script, 4-18
UVARCHAR datatype
Pro*C/C++, 7-19
V
V$NLS_PARAMETERS dynamic performance
view, 3-8
V$NLS_VALID_VALUES dynamic performance
view, 3-8
VARCHAR datatype
Pro*C/C++, 7-18
variable-width multibyte encoding schemes, 2-7
version 8 NCHAR columns
migrating to Oracle9i and later, 11-8
W
wave dash, 7-27
WHERE clause
string comparisons, 9-8
X
XML
parsing in Unicode with Java, 7-32
reading in Unicode with Java, 7-32
writing in Unicode with Java, 7-31
XML programming
Unicode, 7-31
Index-12

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