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PowerDesigner CDM User's Guide
Contents
Index

Conceptual Data Model

User’s Guide

Sybase®PowerDesigner®

12.0

Windows

Part number: DC38084-01-1200-01

Last modiﬁed: December 2005

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Everywhere, Afaria, Answers Anywhere, Applied Meta, Applied Metacomputing, AppModeler, APT Workbench, APT-Build, APT-Edit,

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Contents

About This Manual v

1 Conceptual Data Model Basics 1

WhatisaCDM? ......................... 2

Deﬁning the CDM environment . . . . . . . . . . . . . . . . . 4

DeﬁningaCDM.......................... 13

Deﬁning packages in a CDM . . . . . . . . . . . . . . . . . . 18

2 Using Business Rules in a CDM 21

What is a business rule in CDM? . . . . . . . . . . . . . . . . 22

Deﬁning a business rule in a CDM . . . . . . . . . . . . . . . 23

Working with business rules in a CDM . . . . . . . . . . . . . 27

3 Building Conceptual Data Models 29

Deﬁning data items in a CDM . . . . . . . . . . . . . . . . . . 30

Deﬁning domains in a CDM . . . . . . . . . . . . . . . . . . . 40

Deﬁning entities in a CDM . . . . . . . . . . . . . . . . . . . . 52

Deﬁning entity attributes in a CDM . . . . . . . . . . . . . . . 59

Deﬁning identiﬁers in a CDM . . . . . . . . . . . . . . . . . . 69

Deﬁning relationships in a CDM . . . . . . . . . . . . . . . . . 75

Deﬁning associations in a CDM . . . . . . . . . . . . . . . . . 95

Deﬁning inheritances in a CDM . . . . . . . . . . . . . . . . . 110

Deﬁning check parameters in a CDM . . . . . . . . . . . . . . 123

4 Working with Conceptual Data Models 129

CheckingaCDM......................... 130

Object parameters veriﬁed by Check model . . . . . . . . . . 136

Opening a PAM into a CDM . . . . . . . . . . . . . . . . . . . 151

5 Generating from a Conceptual Data Model 153

Generationbasics ........................ 154

Generating a Conceptual Data Model from a Conceptual

DataModel ......................... 155

Generating a Physical Data Model from a Conceptual Data

Model ............................ 157

Generating an Object Oriented Model from a Conceptual

DataModel ......................... 171

6 CDM Glossary 177

iii

Index 179

About This Manual

Subject

This book describes the PowerDesigner Conceptual Data Model data

modeling environment. It shows you how to do the following:

♦Build a Conceptual Data Model (CDM)

♦Create and use business rules and other model objects

♦Verify the model and import an ERwin model

♦Generate other models from the CDM

Audience

This book is for anyone who will be building data models with the

PowerDesigner Conceptual Data Model. Although it does not assume you

have knowledge about any particular topic, having some familiarity with

relational databases, SQL, and design methodology is helpful. For more

information, see the Bibliography section at the end of this chapter.

Documentation primer

The PowerDesigner modeling environment supports several types of models:

♦Conceptual Data Model (CDM) to model the overall logical structure of

a database, independent from any software or data storage structure

considerations

♦Physical Data Model (PDM) to model the overall physical structure of a

database, taking into account DBMS software or data storage structure

considerations

♦Object Oriented Model (OOM) to model a software system using an

object-oriented approach for Java or other object languages

♦Business Process Model (BPM) to model the means by which one or

more processes are accomplished in operating business practices

♦XML Model (XSM) to model the structure of an XML ﬁle using a DTD

or an XML schema

♦Requirements Model (RQM) to list and document the customer needs

that must be satisﬁed during a development process

♦Information Liquidity Model (ILM) to model the replication of

information from a source database to one or several remote databases

using replication engines

♦Free Model (FEM) to create any kind of chart diagram, in a context-free

environment

This book only explains the Conceptual Data Model. For information on

other models or aspects of PowerDesigner, consult the following books:

General Features Guide To get familiar with the PowerDesigner interface

before learning how to use any of the models.

Physical Data Model User’s Guide To work with the PDM.

Object Oriented Model User’s Guide To work with the OOM.

Business Process Model User’s Guide To work with the BPM.

XML Model User’s Guide To work with an XSM.

Information Liquidity Model User’s Guide To work with an ILM.

Requirements Model User’s Guide To work with an RQM.

Reports User’s Guide To create reports for any or all models.

Repository User’s Guide To work in a multi-user environment using a

central repository.

Typographic conventions

PowerDesigner documentation uses speciﬁc typefaces to help you readily

identify speciﬁc items:

♦monospace text (normal and bold)

Used for: Code samples, commands, compiled functions and ﬁles,

references to variables.

Example: declare user_defined..., the BeforeInsertTrigger

template.

♦bold text

Any new term.

Example: A shortcut has a target object.

♦SMALL CAPS

Any key name.

Example: Press the ENTER key.

Bibliography

Data Modeling Essentials

Graeme Simsion, Van Nostrand Reinhold, 1994, 310 pages; paperbound;

ISBN 1850328773

Information Engineering

James Martin, Prentice Hall, 1990, three volumes of 178, 497, and 625

pages respectively; clothbound, ISBN 0-13-464462-X (vol. 1),

0-13-464885-4 (vol. 2), and 0-13-465501-X (vol. 3).

Celko95

Joe Celko, Joe Celko’s SQL for Smarties (Morgan Kaufmann Publishers,

Inc., 1995), 467 pages; paperbound; ISBN 1-55860-323-9.

vii

viii

CHAPTER 1

Conceptual Data Model Basics

About this chapter This chapter presents the Conceptual Data Model (CDM) and explains the

role of conceptual modeling in the design process.

Contents Topic: page

What is a CDM? 2

Deﬁning the CDM environment 4

Deﬁning a CDM 13

Deﬁning packages in a CDM 18

What is a CDM?

When designing a database, the design process normally starts at the

conceptual level. At the conceptual level, you do not need to consider the

details of actual physical implementation.

A CDM represents the overall logical structure of a database, which is

independent of any software or data storage structure. A conceptual model

often contains data objects not yet implemented in the physical database. It

gives a formal representation of the data needed to run an enterprise or a

business activity.

CDM roles

The CDM allows you to:

♦Represent the organization of data in a graphic format to create Entity

Relationship Diagrams (ERD)

♦Verify the validity of data design

♦Generate a Physical Data Model (PDM), which speciﬁes the physical

implementation of the database

♦Generate an Object-Oriented Model (OOM), which speciﬁes an object

representation of the CDM using the UML standard

♦Generate a Conceptual Data Model (CDM), to create another model

version in order to represent different design stages

+For more information on ERD, see the following book

Information

Engineering

, James Martin, Prentice Hall, 1990, three volumes of 178, 497,

and 625 pages respectively

Logical model

The logical model allows you to design the database structure and perform

some database denormalization actions.

In PowerDesigner, you design a logical model using a PDM with the

<Logical Model>DBMS. This PDM is a physical model with standard

objects, and without DBMS speciﬁc physical options and generation

capabilities.

In the database design process, you use a logical model as an intermediary

step between conceptual and physical design:

♦Start with a CDM containing entities, attributes, relationships, domains,

data items and business rules

Chapter 1. Conceptual Data Model Basics

♦Generate a logical model (PDM with the <Logical Model>DBMS).

Create indexes and specify FK column names and other common features

♦Generate a set of PDMs, each targeted to a speciﬁc DBMS

implementation

If need be, you may develop the CDM in several design steps starting from a

high level model to a low level CDM.

This design process allows you to keep everything consistent in a large

development effort.

+For more information on the physical data model, see the

PDM User’s

Guide

Objects in a CDM

A CDM represents the interaction of the following objects:

Object Tool Description

Domain — Set of values for which a data item is valid

Data item — Elementary piece of information

Entity Person, place, thing, or concept that has charac-

teristics of interest to the enterprise and about

which you want to store information

Entity attribute — Elementary piece of information attached to an

entity

Identiﬁer — Entity attribute, or a combination of entity at-

tributes, whose values uniquely identify each

occurrence of the entity

Relationship Named connection or relation between entities

(Entity Relationship (ER) modeling methodol-

ogy)

Inheritance Special relationship that deﬁnes an entity as a

special case of a more general entity

Association Named connection or association between enti-

ties (Merise modeling methodology)

Association

link

Link that connects an association to an entity and

on which you deﬁne the cardinality an entity has

relative to another

Deﬁning the CDM environment

The CDM environment includes a set of parameters and conﬁguration

options that deﬁne various aspects of the model content and behavior. You

can set these parameters:

♦At model creation

♦After creating a model with default options and parameters

♦When creating a model template

CDM options

♦You can set the following CDM options:

♦All Objects, see section “All objects” on page 5

♦Notation, see section “Notation” on page 6

♦Data item, see section “Data item” on page 9

♦Relationship, see section “Relationship” on page 10

♦Domain/attribute, see section “Domain and attribute” on page 10

Chapter 1. Conceptual Data Model Basics

vTo deﬁne CDM options

1. Select Tools äModel options.

Right-click the diagram background, and select Model Options from the

contextual menu.

The Model Options dialog box opens to the Model Settings page.

2. Select CDM options in the different groupboxes.

3. Click OK.

All objects

Name/Code case

sensitive

You can deﬁne the case sensitivity of names and codes for all objects in the

current model. When this check box is selected, it implies that you can have

two objects with identical name or code but different case in the same

namespace.

Unlike other model options, you can modify the name and code case

sensitivity during the design process. However, if you do so, make sure you

run the check model feature to verify if the model does not contain any

duplicate object.

Enable links to

requirements

Requirements are descriptions of customer needs that must be satisﬁed

during development processes.

You can enable links to requirements for all objects in the current model.

When this check box is selected, it implies that the Requirements tab

Deﬁning the CDM environment

appears in the objects property sheet. The Requirements page allows you to

attach requirements to objects; these requirements are deﬁned in the

Requirements models open in the workspace. Attached requirements and

Requirements models are synchronized.

+For more information on requirements, see the

Requirements Model

User’s Guide

Notation

You can choose to use one or both of the following notation types in the

current model:

Chapter 1. Conceptual Data Model Basics

Option Description Symbols

Entity / Rela-

tionships

Entity/relationship no-

tation connects entities

with links representing

one of four relationships

between them. These

relationships have prop-

erties that apply to both

entities involved in the

relationship

Merise Merise notation uses

associations instead of

relationships

E/R + Merise Both entity/relationship

and Merise are used in

the same model

Both types of symbols

IDEF1X Data modeling notation

for relationships and en-

tities. In this notation,

each set of relationship

symbols describes a

combination of the op-

tionality and cardinality

of the entity next to it

The Entity / Relationships notation is the default notation used in this

manual.

When you change notation, all symbols in all diagrams are updated

accordingly.

IDEF1X notation Entities display rounded rectangles when they depend on another entity

Deﬁning the CDM environment

either through an inheritance link or when the relationship has the dependent

property selected.

Relationships: unlike the other notations, relationship symbols cannot be

parsed in terms of optionality and cardinality independently. Each set of

symbols describes a combination of the optionality and cardinality of the

entity next to it.

Cardinality Representation

One - Many

One - One or Many - Many

One - One dependent dis-

plays a continuous line and

entity with rounded angles

PowerDesigner does not support the following notation:

Sub-type or inheritance symbol changes according to the Complete

property:

Chapter 1. Conceptual Data Model Basics

Complete Symbol

Yes

Data item

You can choose to use one or both of the following data item options in the

current model:

Option Description

Unique code When selected, requires that data items have unique codes

Allow reuse When selected, makes it possible to reuse one data item

as an attribute for more than one entity provided the

attributes have same name and data type and do not

belong to a primary key.

When deselected or when the attribute belongs to a

primary key, the data item cannot be reused. In this case,

if the Unique code check box is selected, a new data

item with identical name but different code is created,

otherwise a new data item with identical name and code

is created

Deleting entity attributes When you delete an entity or entity attributes, data item options determine

whether or not the corresponding data items are also deleted.

The following rules apply to deleted entity attributes:

Data item options Result of deleting an entity attribute

Unique Code

Allow Reuse

Deletes entity attribute

Does not delete corresponding data item

Unique Code only Deletes entity attribute

Does not delete corresponding data item

Allow Reuse only Deletes entity attribute

Deletes corresponding data item if it is not used by

another entity

None Deletes entity attribute

Deletes corresponding data item

Deﬁning the CDM environment

Relationship

You can choose to select or clear the Unique code option. When selected, it

requires that relationships have unique codes.

Domain and attribute

From the Attribute and Domain groupbox in Model Options, you can choose

to enforce non-divergence between a domain deﬁnition and the attributes

using the domain, for the following attribute properties:

Property Attributes in the domain cannot have divergent

Data type Data type, length, and precision

Check Check parameters

Rules Business rules

Mandatory Entity, association and inheritance attribute mandatory

property

Enforce non-divergence

selected

In this mode, the selected attribute properties must be consistent with the

domain properties.

When you apply the Enforce non-divergence options You are asked if

you want to apply domain properties to attributes attached to the domain in

the current model.

♦If you accept to apply domain properties, the attribute properties are

modiﬁed in order to be consistent with domain properties. However, if

the check parameters, business rules, and mandatory value of an attribute

are more constrained than those of the domain, these properties will not

be modiﬁed. You may indeed need to deﬁne a shorter range of values in

the attribute check parameters, or set an attribute as mandatory while the

domain is not

♦If you refuse to apply domain properties, the attribute is detached from

the domain

When you modify the properties of a domain The properties of the

attributes attached to the domain are updated provided these properties are

selected in the Model Options dialog box.

Attributes cannot be modiﬁed When you select an attribute property

under Enforce non-divergence, each instance of that attribute property in the

lists of attributes and the property sheets of attributes appears grayed and can

not be modiﬁed.

Chapter 1. Conceptual Data Model Basics

If you want to modify an attribute property that is deﬁned as non-divergent,

you must detach the attribute from its domain, or clear the Enforce

non-divergence check box in Model Options.

Enforce non-divergence

deselected

In this mode, it is still possible to select attribute properties under Enforce

non-divergence.

If you select one or more of the attribute properties When you modify

an attribute property so that it diverges from its current domain deﬁnition,

you are asked if you want to keep the modiﬁcations and diverge from the

domain.

If you do not select attribute properties When you modify an attribute or

domain property resulting in a divergence, you are not warned, and you can

no longer cascade the change on the attribute properties.

Default data type In a CDM, you can select a Default data type to apply to domains and

attributes if no data type is selected for them.

If you modify CDM options, these options apply only to the current CDM.

+For information on other model options, see chapter Working with

Models.

CDM extended model deﬁnitions

An extended model deﬁnition allows you to expand object deﬁnitions and

complement the generation targets and commands. Extended model

deﬁnitions are created and saved in ﬁles with the XEM extension. You can

create or attach one or several extended model deﬁnitions to a model.

Extended model deﬁnitions may contain:

♦Extended attributes for applicable objects in order to further deﬁne their

properties

Stereotypes to deﬁne extended dependencies established between model

objects

+For more information on extended dependencies, see “CDM extended

dependencies” on page 12.

♦Generation targets and commands to complement the generation of an

object model, or to perform an extended generation

+For more information on extended model deﬁnitions, see chapter

Extended Model Deﬁnitions Reference Guide in the Advanced User

Documentation.

Deﬁning the CDM environment

CDM extended dependencies

Extended dependencies are links between CDM objects. These links help to

make object relationships clearer but are not interpreted and checked by

PowerDesigner, as they are meant to be used for documentation purposes

only.

You can complement these links by applying stereotypes. Stereotypes are

used to deﬁne extended dependencies between objects in the CDM.

You can type stereotypes directly in the Stereotype column of the object

property sheet or select a value from the dropdown listbox if you have

previously deﬁned stereotypes in an embedded or imported extended model

deﬁnition (.XEM).

+For more information on extended dependencies, see section Using

Extended Dependencies in chapter Using the PowerDesigner Interface in the

General Features Guide.

Chapter 1. Conceptual Data Model Basics

Deﬁning a CDM

You can create a new CDM, or open an existing CDM.

CDM properties

The Model property sheet displays the deﬁnition of the current model. From

this property sheet you can modify the model deﬁnition.

A CDM has the following model properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the model

Filename Location of the model ﬁle. This box is empty if the model has

never been saved

Author Author of the model. You can insert a name, a space, or nothing.

If you insert a space, the Author ﬁeld in the title box remains

empty.

If you intentionally leave the box empty, the Author ﬁeld in the

title box displays the user name from the Version Info page of

the model property sheet

Version Version of the model. You can use this box to display the

repository version or a user deﬁned version of the model. This

parameter is deﬁned in the Title page of the model display

preferences

Default

diagram

Diagram displayed by default when you open the model

vTo modify CDM properties

1. Select Model äModel Properties.

Right-click the diagram background, and select Properties from the

contextual menu.

Deﬁning a CDM

If you have inserted a title box, click the Property tool and then click the

title box.

The model property sheet appears.

2. Type changes to model properties.

3. Click OK.

Creating a CDM

There are several ways to create a CDM:

♦Create a new CDM

♦Create a new CDM using a template

♦Create a new CDM using existing elements (importing one or more

CDMs, importing a ProcessAnalyst Model (.PAM) or an ERwin model

(.ERX) or generating from a PDM or OOM, etc.)

Creating a CDM using the New model option

Chapter 1. Conceptual Data Model Basics

vTo create a new CDM using the New model option

1. Select File äNew to display the New dialog box.

2. Select Conceptual Data Model in the list of model types.

3. Select the New model radio button in the upper right part of the dialog

box.

4. Type a model name in the Model name box. The code of the model,

which may be used for script or code generation, is derived from this

name according to the model naming conventions.

5. Click OK.

A new CDM is created in the Workspace.

6. Select Model äModel Properties.

The model property sheet appears.

7. Modify the name and code of the model.

8. Click OK.

Demo example

An example of a CDM is available in the Examples directory.

Deﬁning a CDM

Creating a CDM using the New model from template option

vTo create a new CDM using the New model from template option

1. Select File äNew to display the New dialog box.

2. Select Conceptual Data Model in the list of model types.

3. Select the New model from template radio button in the upper right part

of the dialog box.

4. Select a model template from the list.

List of templates

You can select user-deﬁned model templates (use the Change User-

Deﬁned Model Templates Folder tool to specify the user templates

folder) and copy some existing models as model templates using the

Copy Model to User-Deﬁned Model Templates Folder tool.

+For more information on model templates, see section Creating a

model in chapter Managing Models, in the

General Features Guide.

5. Click OK.

A new CDM is created in the Workspace.

6. Select Model äModel Properties.

The model property sheet appears.

7. Type a model name and code.

8. Click OK.

Demo example

An example of an CDM is available in the Examples directory.

Opening an existing CDM

A Conceptual Data Model has the ﬁle extension .CDM.

vTo open an existing CDM

1. Select File äOpen to display a standard open ﬁle dialog box.

2. Select a ﬁle with the .CDM extension.

Chapter 1. Conceptual Data Model Basics

3. Click Open.

The model appears in the Browser and the diagram opens in the diagram

window.

Detaching a CDM from the workspace

You can detach a CDM from a workspace. When a CDM is detached from a

Workspace its node is removed from the Browser and it is no longer deﬁned

in the workspace, but the ﬁle is not deleted from your operating environment.

vTo detach a CDM from a workspace

1. Right-click the CDM node in the Browser and select Detach From

Workspace from the contextual menu.

A conﬁrmation box asks if you want to save the CDM.

2. Click Yes if you want to save modiﬁcations to the CDM.

Select or browse to a directory.

Type a name for the ﬁle and click the Save button.

Click No if you do not want to save modiﬁcations to the ﬁle.

The CDM is removed from the workspace.

Saving and closing a CDM

You save a CDM by selecting File äSave.

You close a CDM by selecting File äClose.

Deﬁning packages in a CDM

A package is a piece of a model.

+When working with a large model, you can split the model into smaller

subdivisions to avoid manipulating the entire set of model objects. Packages

can be useful to assign portions of a model, representing different tasks and

subject areas, to different development teams.

Package hierarchy You can create several packages at the same hierarchical level within a

model or decompose a package into other packages and continue this

process without limitation in decomposition depth. Each package appears

with a default diagram window. At each level of decomposition you can

create several diagrams.

+For more information on packages, see the

General Features Guide

Composite view You can expand a package to have a global view of the whole diagram

content.

To do so, you have to right-click a package and select Composite View from

the contextual menu. You must resize the composite package symbol to

visualize its content:

To return to the package normal view, re-select the Composite View

command in the contextual menu of the expanded package.

Note that if you double-click the composite view, you automatically open

the sub-package diagram.

Chapter 1. Conceptual Data Model Basics

+For more information on the composite view feature, see section

Expanding the symbol of a composite object in chapter Model Graphics in

the General Features Guide.

CDM package properties

Packages have properties displayed on property sheets. All packages share

the following common properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Optional label that describes a package and provides additional

information

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Default dia-

gram

Diagram displayed by default when you open the package

Use Parent

Namespace

Deﬁnes the package as being the area in which the name of an

object must be unique in order to be used.

Creating a CDM package

A package always belongs to a model. You create a package like any other

model objects.

The name of each package must be unique in the model.

There are several ways to create a package:

♦From a diagram

♦From the Browser

♦From the list of packages

At creation, a package has a default name including a number, this number is

assigned in the order of creation.

Deﬁning packages in a CDM

+For more information on the different ways to create a package, see

section Creating an object in chapter managing Objects.

Modifying package display preference

You can modify the following display preference for packages using the

Tools äDisplay Preferences command:

Preference Description

Stereotype Displays the stereotype of the package

CHAPTER 2

Using Business Rules in a CDM

About this chapter This chapter describes how business rules help you model information.

Contents Topic: page

What is a business rule in CDM? 22

Deﬁning a business rule in a CDM 23

Working with business rules in a CDM 27

What is a business rule in CDM?

A business rule is a rule that your business follows. A business rule could be

a government-imposed law, a customer requirement, or an internal guideline.

Starts as an observation Business rules often start as simple observations, for example “customers

call toll-free numbers to place orders.” During the design process they

develop into more detailed expressions, for example what information a

customer supplies when placing an order or how much a customer can spend

based on a credit limit.

Guides modeling Business rules guide and document the creation of a model. For example,

the rule “an employee belongs to only one division” can help you

graphically build the link between an employee and a division.

Complements graphics Business rules complement model graphics with information that is not

easily represented graphically. For example, some rules specify physical

concerns in the form of formulas and validation rules. These technical

expressions do not have a graphical representation.

CDM to PDM generation During generation of a Physical Data Model (PDM), or an Object-Oriented

Model (OOM), from a CDM, the business rules transfer directly into the

PDM or OOM. In the generated model, you further specify business rules to

suit physical concerns.

Chapter 2. Using Business Rules in a CDM

Deﬁning a business rule in a CDM

You can deﬁne a business rule which can be attached to CDM objects.

Business rule properties in a CDM

A business rule deﬁnition includes the following properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the rule

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Type Indicates whether the rule is a deﬁnition, a fact, a formula, or

a validation

A business rule deﬁnition also includes the following properties, each with

their respective page:

Property Description

Expression Presence of associated expression

Notes Presence of associated notes

Types of business rule in an CDM

The different business rule types that you can deﬁne in a CDM are described

below:

Deﬁning a business rule in a CDM

Rule type Describes Example

Deﬁnition Properties of the element in

the information system

A customer is a person identi-

ﬁed by a name and an address

Fact Certainty, existence in the

information system

A client may place one or

more orders

Formula Calculation used in the in-

formation system

The total order is the sum of

all the order line costs

Requirement Functional speciﬁcation in

the information system

The model is designed so that

total losses do not exceed 10%

of total sales

Validation Constraint on a value in the

information system

The sum of all orders for a

client must not be greater than

that client’s allowance

Constraint Additional check constraint

on a value. Constraint busi-

ness rules are used in the

PDM, they are generated in

the database

The start date should be in-

ferior to the end date of a

project

+For more information on constraint type, see section Using constraint

business rules in a PDM in chapter Using Business Rules in a PDM in the

Physical Data Model User’s Guide

Creating a business rule in a CDM

Before you create business rules, formulate your rules by asking yourself the

following questions:

♦What business problems do I want to address?

♦Are there any procedures that my system must respect?

♦Do any speciﬁcations dictate the scope of my project?

♦Do any constraints limit my options?

♦How do I describe each of these procedures, speciﬁcations, and

constraints?

♦How do I classify these descriptions: as deﬁnitions, facts, formulas, or

validation rules?

Chapter 2. Using Business Rules in a CDM

vTo create a business rule in a CDM

1. Select Model äBusiness Rules to display the List of Business Rules. It

displays the business rules deﬁned for the model.

2. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line.

3. Type a name and a code for the business rule.

4. Click Apply.

The creation of the new business rule is committed.

5. Click the new business rule line.

An arrow appears at the beginning of the line.

6. Click the Properties tool.

Double click the arrow at the beginning of the line.

The property sheet for the new business rule appears.

7. Click the General tab and select a business rule type from the Type

dropdown listbox.

8. Click OK in each of the dialog boxes.

Deﬁning a business rule in a CDM

Attaching an expression to a business rule in a CDM

A business rule typically starts out as a description. As you develop your

model and analyze your business problem, you can complete a rule by

adding a technical expression. The syntax of expressions depends on the

target database.

Each business rule can include two types of expression:

♦Server

♦Client

Only the server expression can be generated to a database. You can generate

server expressions as check parameters if they are attached to tables,

domains, or columns.

A client expression is used mainly for documentation purposes. However,

you can insert both types of expression into a trigger or a stored procedure.

vTo attach an expression to a business rule in a CDM

1. Select Model äBusiness Rules to display the List of Business Rules.

2. Double-click the new business rule line to display the business rule

property sheet.

3. Click the Expression tab to display the Expression page.

4. Click the Server tab at the bottom of the page to deﬁne a server

expression.

Click the Client tab at the bottom of the page to deﬁne a client expression.

5. Type an expression in the Expression textbox.

6. Click OK in each of the dialog boxes.

Chapter 2. Using Business Rules in a CDM

Working with business rules in a CDM

You can apply a business rule to an object from its property sheet.

Applying a business rule to the current CDM object

You can choose a rule to apply to the current object from its property sheet.

vTo apply a business rule to the current CDM object

1. Double-click an object in the diagram to display the object property sheet.

2. Click the Rules tab to display the Rules page showing any business rules

attached to the object.

3. Click the Add Objects tool to display a selection list of business rules.

It contains a list of all the business rules of the model, except the rules

that already belong to the object.

4. Select the business rules you want to add to the object.

5. Click OK.

The business rules are added to the object and appear in the list of

business rules for the object.

Working with business rules in a CDM

6. Click OK.

U Column in the List of business rules

When you apply a business rule to an object, the U (Used) column

beside this business rule is automatically checked in the List of business

rules to indicate that the business rule is used by at least one object in

the model. The U column allows you to visualize unused business rules,

you can then delete them if necessary.

CHAPTER 3

Building Conceptual Data Models

About this chapter This chapter describes how to build a Conceptual Data Model (CDM). It

explains the role of each object in a conceptual model and shows how to

modify them in a conceptual diagram.

Contents Topic: page

Deﬁning data items in a CDM 30

Deﬁning domains in a CDM 40

Deﬁning entities in a CDM 52

Deﬁning entity attributes in a CDM 59

Deﬁning identiﬁers in a CDM 69

Deﬁning relationships in a CDM 75

Deﬁning associations in a CDM 95

Deﬁning inheritances in a CDM 110

Deﬁning check parameters in a CDM 123

Deﬁning data items in a CDM

Adata item is an elementary piece of information in a model. It represents

a fact or a deﬁnition in an information system, which may or may not have

any eventual existence as a modeled object.

You can attach a data item to an entity. It then becomes an entity attribute of

that entity. When a physical data model (PDM) is generated from a CDM,

an entity attribute generates a column in a table.

You can also deﬁne a data item, but not attach it to an entity. It remains

deﬁned in the model and can be attached to an entity at any time.

Depending on its deﬁned model options, a data item can be unique in the

model, or unique only for a particular entity. In the latter case, a data item is

equivalent to an entity attribute.

Example In the information system for a publishing company, the last names for

authors and customers are both important pieces of business information.

The data item LAST NAME is created to represent this information. It is

attached to the entities AUTHOR and CUSTOMER, and becomes entity

attributes of those entities.

Another piece of information is the date of birth of each author. The data

item BIRTH DATE is created in the CDM, but as there is no immediate need

for this information in the model, it remains in the CDM, but is not attached

to any entity.

Data item properties

You can access data item properties from the list of data items. Each data

item deﬁnition includes the following general properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the data item

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Chapter 3. Building Conceptual Data Models

Property Description

Data type Code indicating the data format, such as N for numeric or A

for alphanumeric, followed by the number of characters

Length Maximum number of characters

Precision Number of places after the decimal point, for data values that

can take a decimal point

Domain Name of the associated domain

A data item deﬁnition also includes the following properties, each with their

own respective property sheets:

Property Description

Standard checks Check parameters deﬁned for the domain

Additional checks Domain constraints or validation rules not deﬁned by

standard check parameters

Rules Business rules attached to the domain

Creating a data item

There are several ways to create a data item:

♦From the list of data items

♦From the Browser

At creation, a data item has a default name including a number. This number

is assigned in the order of creation of objects.

+For more information on the different ways to create a data item, see

section Creating an object in chapter Managing objects in the

General

Features Guide

Deﬁning data items in a CDM

vTo create a data item from the list of data items

1. Select Model äData Items to display the list of data items.

2. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line.

3. Type a data item name and a data item code.

4. (Optional) Click the Data Type column for the same row.

Display the column you need

If you do not see the column you need, display it with the Customize

Columns and Filter tool. For details, see the

General Features Guide

Click the down arrowhead and select a data type from the dropdown

listbox.

Click the ellipsis button to display the list of standard data types and click

the radio button corresponding to the data type you want to apply.

Type the maximum number of characters for the data item in the Length

box.

If the data type can include values that take a decimal point, type the

number of places after the decimal point in the Precision box.

Click OK.

Chapter 3. Building Conceptual Data Models

5. (Optional) Click the Domain column for the same row.

Select a domain from the dropdown listbox.

6. Click OK.

+For more information on selecting a data type for a domain see section

“Selecting a data type for a domain in a CDM” on page 42.

+For information on indicating data type length and precision, see section

“Indicating data type, length, and precision in a CDM” on page 42.

+For more information on attaching a data item to a domain, see section

“Attaching a data item to a domain” on page 36.

Deleting a data item

You delete a data item from the list of data items. When you delete a data

item you also delete all entity attributes using that data item.

vTo delete a data item

1. Select äModel äData Items to display the list of data items.

2. Click a data item in the list.

An arrow appears at the beginning of the line.

Deﬁning data items in a CDM

Selecting a line in a list

You can select a line in a list by clicking the number at the beginning of

the line. An arrow replaces the number and the line is selected.

3. Click the arrow at the beginning of the line.

The line is selected.

4. Click the Delete tool.

Press DELETE.

The data item and all entity attributes using the data item are deleted.

5. Click OK.

Copying a data item in the list

You can copy and paste a data item in the list of data items. Copying a data

item creates a new data item.

Same code for different data items

If you do not choose the Unique Code data item option, you can use the

same code for different data items as long as each of these data items is

attached to a different entity. You access data item options by selecting

Tools äModel Options.

vTo copy a data item in the list

1. Select Model äData Items to display the list of data items.

It lists the data items deﬁned in the model.

2. Click the line for the data item that you want to copy.

An arrow appears at the beginning of the line.

3. Click the arrow at the beginning of the line.

The line is selected.

4. Click the Copy tool.

5. Click the Paste tool.

The data item is copied to the next line in the list. If the Unique code data

item option is selected in Model Options, the copied data item is

renamed.

Chapter 3. Building Conceptual Data Models

Deﬁning code and reuse options for data items

You can deﬁne the following options for data items:

Option Result when selected Result when cleared

Unique code Each data item has a unique

code

Different data items can

have the same code

Allow reuse One data item can be an entity

attribute for more than one

entity

One data item can be an

entity attribute for only one

entity

If you do not select Unique Code, two data items can have the same code. In

this case, you differentiate the data items by the entities that use them. The

entities are listed in the Dependencies column of the list of data items.

Item not visible in list

To make an item visible in a list, click the Customize Columns and Filter

tool in the list toolbar, select the appropriate check box from the list of ﬁlter

options that appears, and click OK.

vTo deﬁne code and reuse options for data items

1. Select Tools äModel Options.

The Model Options dialog box opens to the Model Settings page.

Deﬁning data items in a CDM

2. Select the Unique Code check box in the Data Item groupbox to require a

unique code for each data item.

Clear the Unique Code check box in the Data Item groupbox to allow

more than one data item to have the same code.

3. Select the Allow Reuse check box to allow the one data item to be an

entity attribute for more than one entity.

Clear the Allow Reuse check box to prohibit the one data item from

being an entity attribute for more than one entity.

4. Click OK.

Error message The following error message appear when you select the Unique Code, when

it is incompatible with the current CDM:

Error message Solution

Unique Code option could not be

selected because two data items have

the same code:

data_item_code

Assign unique codes to all data

items

Attaching a data item to a domain

If you attach a data item to a domain, the domain supplies the data type and

related data characteristics.

The domain applies a standard data type to the data item. It can also apply

length, decimal precision, and check parameters.

vTo attach a data item to a domain

1. Select Model äData Items to display the list of data items.

2. Click the data item to deﬁne.

An arrow appears at the beginning of the line.

3. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The data item property sheet opens to the General page.

Chapter 3. Building Conceptual Data Models

Opening property sheets at last accessed page

You can choose to open property sheets at the last accessed page by

selecting Tools äGeneral Options äDialog, and selecting the option

Keep Last Tab in the Property Sheets groupbox.

4. Select a domain from the Domain dropdown listbox at the bottom of the

dialog box and click OK.

Click the Ellipsis button at the end of the Domain dropdown listbox.

Select a domain from the list that appears and click OK.

You return to the list of data items. In the Data Type column, the data type

for the domain replaces the data type previously deﬁned for the data item.

5. Click OK.

Selecting a data type for a data item

There are two ways to select a data type for a data item.

♦Attach the data item to a domain The domain dictates a standard

data type, a length, and a level of precision, as well as optional check

parameters

♦Manually select a data type You select a standard data type along

with a length, a level of precision, and optional check parameters

Deﬁning data items in a CDM

+For more information on attaching a data item to a domain, see

section “Attaching a data item to a domain” on page 36.

About check parameters

Check parameters indicate data ranges and validation rules. You can attach

check parameters to entity attributes, data items, or domains.

vTo select a data type for a data item

1. Select Model äData Items to display the list of data items.

2. Click the data item to deﬁne.

An arrow appears at the beginning of the line.

3. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The data item property sheet opens to the General page.

4. Select a data type from the Data Type dropdown listbox.

Click the Question mark button at the end of the Data Type dropdown

listbox.

Chapter 3. Building Conceptual Data Models

A list of standard data types appears.

Select the radio button corresponding to the data type you want to apply.

Click OK.

Undeﬁned data type

If you do not want to select a data type immediately, you can choose the

<UNDEF>data type.

5. Type the maximum number of characters for the data type in the Length

box.

6. If the data type can include values that take a decimal point, type the

number of places after the decimal point in the Precision box.

7. Click OK.

The new data type appears in the list of data items.

Conﬁguring the display of the list of data items

You can sort the data items in the list:

♦By any property that appears in the column header in the lists

♦Alphabetical or reverse alphabetical order

The listed order is indicated by an arrowhead that appears in the property

column header. Each time you click a column header, you change the listed

order for that column, according to the displayed arrow.

Each arrow type corresponds to the following list orders:

Arrow type Listed order

Down arrow Alphabetically

Up arrow Reverse alphabetically

For example, when you click the column header Name, the data items are

listed by name alphabetically when the Down arrow is indicated, and in

reverse order when the Up arrow is indicated.

vTo conﬁgure the display of the list of data items

1. Select Model äData Items to display the list of data items.

2. Click a property title bar.

The listed columns are ordered by the indicated property.

3. Click OK.

Deﬁning domains in a CDM

Domains help you identify the types of information in your model. Applying

domains to data items makes it easier to standardize data characteristics for

entity attributes in different entities.

In a CDM, you can associate the following information with the domain:

♦Data type, length, and precision

♦Check parameters

♦Business rules

♦Mandatory

Domain properties in a CDM

You can access domain properties from the list of domains.

Each domain deﬁnition includes the following general properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the domain

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Data type Form of the data corresponding to the domain, such as

numeric, alphanumeric, boolean, or others

Length Maximum number of characters

Precision Number of places after the decimal point, for data values that

can take a decimal point

Mandatory Domain values are mandatory for all entity attributes using

that domain

A domain deﬁnition can also include the following properties, which have

Chapter 3. Building Conceptual Data Models

associated values or information used by entity attributes using the domain:

Property Description

Standard checks Check parameters deﬁned for the domain

Additional checks Domain constraints or validation rules not deﬁned by

standard check parameters

Rules Business rules attached to the domain

Creating a domain in a CDM

There are several ways to create a domain:

♦From the list of domains

♦From the Browser

At creation, a domain has a default name including a number. This number

is assigned in the order of creation of objects.

+For more information on the different ways to create a domain, see

section Creating an object in chapter Managing objects in the

General

Features Guide

vTo create a domain in a CDM from the list of domain

1. Select Model äDomains to display the list of domains.

2. Click a blank line in the list.

Click the Add a Row tool.

Deﬁning domains in a CDM

An arrow appears at the beginning of the line.

3. Type a domain name and a domain code.

4. Click Apply.

5. Click the Properties tool.

Double-click the arrow at the beginning of the line.

6. Select a data type from the dropdown listbox.

7. Specify length and precision as required.

8. Click OK in each of the dialog boxes.

Indicating data type, length, and precision in a CDM

Length and precision The properties length and precision do not apply to all data types.

Depending on data type, length may indicate a maximum or a ﬁxed number

of characters.

In the list of available data types, a variable indicates where you have to type

a length or precision, as follows:

Variable Replace with

%n Length

%s Length with precision

%p Decimal precision

For example, if you are using Sybase Adaptive Server Anywhere and you

choose the data type char(%n), you can choose a length of ten by typing

char(10).

Undeﬁned data type All target DBMS allow you to select the <undeﬁned>data type. The

<undeﬁned>data type indicates which domains remain without data types.

If an <undeﬁned>data type is present when you generate your database, it

is replaced by the default data type for your database.

Selecting a data type for a domain in a CDM

You can select a data type for a domain in two ways:

♦From the list of domains

♦From the domain property sheet

Chapter 3. Building Conceptual Data Models

The list of standard data

types

When you select a data type for a domain from its property sheet, you can

choose from a list of standard data types. This list presents the available data

types in full details instead of the abbreviated format used in the data type

dropdown listbox in the list of domains.

Selecting a data type for a CDM domain from the list

vTo select a data type for a CDM domain from the list

1. Select Model äDomains to display the list of domains.

2. Click the domain to deﬁne.

An arrow appears at the beginning of the line.

3. Click the Data Type column.

4. Select a data type from the Data Type dropdown listbox.

Deﬁning a data type later

If you do not want to select a data type immediately, you can choose the

<UNDEF>data type.

5. Click OK.

The data type appears in the Data Type column of the list of domains.

Selecting a data type for a CDM domain from its property sheet

vTo select a data type for a CDM domain from its property sheet

1. Select Model äDomains to display the list of domains.

2. Click the domain to deﬁne.

An arrow appears at the beginning of the line.

3. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The domain property sheet appears.

4. Select a data type from the Data Type dropdown listbox.

Selecting a data type from a list of standard data types

To select a data type from a list of standard data types, click the Question

Mark button at the end of the Data Type dropdown listbox, and select

the radio button for a data type from the list that appears.

Deﬁning domains in a CDM

5. Type the maximum number of characters for the data item in the Length

box.

6. If the data type can include values that take a decimal point, type the

number of places after the decimal point in the Precision box.

7. Click OK.

The change of data type appears in the list of domains.

Undeﬁned data type

If you do not want to select a data type immediately, you can choose the

<Undeﬁned>data type.

Selecting a data type from a list of standard data types in a CDM

You can select a data type from a list of standard data types. This is the same

list that is available in the Physical Data Model. PowerDesigner

automatically maps the standard data type to a conceptual data type.

The length and precision are properties that do not apply to all data types.

Furthermore, depending on data type, length may indicate a maximum or a

ﬁxed number of characters.

The tables below indicates the data types for which you can specify:

♦Fixed length

♦Maximum length

♦Decimal precision

Numeric data types

Conceptual data

type

Physical data type

(depending on the

DBMS)

Content Length

Integer int / INTEGER 32-bit integer —

Short Integer smallint / SMALL-

INT

16-bit integer —

Long Integer int / INTEGER 32-bit integer —

Byte tinyint / SMALLINT 256 values —

Number numeric / NUMBER Numbers with

a ﬁxed deci-

mal point

Fixed

Chapter 3. Building Conceptual Data Models

Conceptual data

type

Physical data type

(depending on the

DBMS)

Content Length

Decimal decimal / NUMBER Numbers with

a ﬁxed deci-

mal point

Fixed

Float ﬂoat / FLOAT 32-bit ﬂoating

point numbers

Fixed

Short Float real / FLOAT Less than 32-

bit point deci-

mal number ♦—

Long Float double precision /

BINARY DOUBLE

64-bit ﬂoating

point numbers

—

Money money / NUMBER Numbers with

a ﬁxed deci-

mal point

Fixed

Serial numeric / NUMBER Automatically

incremented

numbers

Fixed

Boolean bit / SMALLINT Two oppos-

ing values

(true/false;

yes/no; 1/0)

—

Character data types

Deﬁning domains in a CDM

Conceptual data

type

Physical data

type (depend-

ing on the

DBMS)

Content Length

Characters char / CHAR Character strings Fixed

Variable Charac-

ters

varchar / VAR-

CHAR2

Character strings Maximum

Long Characters varchar /

CLOB

Character strings Maximum

Long Var Charac-

ters

text / CLOB Character strings Maximum

Text text / CLOB Character strings Maximum

Multibyte nchar /

NCHAR

Multibyte character

strings

Fixed

Variable Multibyte nvarchar /

NVARCHAR2

Multibyte character

strings

Maximum

Time data types

Conceptual data type Physical data type

(depending on the

DBMS)

Content

Date date / DATE Day, month, year

Time time / DATE Hour, minute, and second

Date & Time datetime / DATE Date and time

Timestamp timestamp / TIMES-

TAMP

System date and time

Other data types

Chapter 3. Building Conceptual Data Models

Conceptual data

type

Physical data

type (depend-

ing on the

DBMS)

Content Length

Binary binary / RAW Binary strings Maximum

Long Binary image / BLOB Binary strings Maximum

Bitmap image / BLOB Images in bitmap

format (BMP)

Maximum

Image image / BLOB Images Maximum

OLE image / BLOB OLE links Maximum

Other — User-deﬁned data

type

—

Undeﬁned undeﬁned Not yet deﬁned data

type

—

vTo select a data type from a list of standard data types in a CDM

1. Select Model äDomains to display the list of domains.

2. Click the domain to deﬁne and display an arrow at the beginning of the

line.

3. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The domain property sheet appears.

4. Click the Question Mark button next to the Data Type dropdown listbox.

Selecting from the Data Type dropdown listbox

You can also select a data type directly from the Data Type dropdown

listbox.

A list of standard data types appears.

Deﬁning domains in a CDM

5. Click the radio button corresponding to the data type you want to apply.

The code for the data type appears in the Code box.

Undeﬁned data type

If you do not want to select a data type immediately, you can choose the

Undeﬁned data type.

6. Type the maximum number of characters for the data type in the Length

box.

7. If the data type includes values after a decimal point, type the number of

places after the decimal point in the Precision box.

8. Click OK.

The change of data type appears in the Data Type box.

Modifying domain properties in a CDM

You can modify domain properties from the domain property sheet.

When you modify domain properties, a conﬁrmation box appears asking if

you want to modify the data items and attributes currently using the domain.

Chapter 3. Building Conceptual Data Models

The Data Type check box is automatically selected and available for an

update, depending on the options set to enforce non-divergence from a

domain.

For information on domain divergence, see section “Enforcing

non-divergence from domains in a CDM” on page 50.

You can also select other properties (Check, Rules) that will be updated in

their use of the domain.

You can now click one of the following buttons with the following effects:

Button Effect

Yes The data items currently using the domain are modiﬁed

according to the update

No The data items currently using the domain are not modiﬁed

according to the update but the current modiﬁcation is accepted

if domain divergence is allowed in the model options

Cancel The update is cancelled and nothing is changed

vTo modify domain properties in a CDM

1. Select Model äDomains to display the list of domains.

2. Click a domain from the list.

An arrow appears at the beginning of the line.

3. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The Domain property sheet appears.

Deﬁning domains in a CDM

4. Type changes to domain properties.

Click on a page tab.

Type or select domain properties as required.

5. Click OK.

If the domain is used by one or more data items, an update conﬁrmation

box appears asking if you want to modify domain properties for the data

items using the domain.

6. Select the properties that you want to update for all data items using the

domain.

7. Click Yes.

Enforcing non-divergence from domains in a CDM

From the Model Options dialog box, you can choose to enforce

non-divergence between a domain and the data items and attributes that use

the domain.

+For more information on non-divergence enforcement, see section

Deﬁning CDM Options in chapter Conceptual Data Model Basics.

Chapter 3. Building Conceptual Data Models

vTo enforce domain non-divergence in a CDM

1. Select Tools äModel Options.

Right click the diagram background.

Select Model Options from the contextual menu.

The Model Options dialog box opens to the Model Settings page.

2. Select the Enforce non-divergence check box in the Domain/Attribute

groupbox.

3. Select check boxes for the entity attribute properties that are not

permitted to diverge from the domain deﬁnition.

4. Click OK.

Deﬁning entities in a CDM

An entity represents an object deﬁned within the information system about

which you want to store information. For example, in a model concerning

employees and divisions, the entities are Employee and Division.

An occurrence of an entity is an individual element belonging to the entity.

For example, the employee Martin is one occurrence of the entity Employee.

Entity properties

You can double-click any entity symbol in the diagram to display its

property sheet:

Property Description

Name The name of the item which should be clear and meaning-

ful, and should convey the item’s purpose to non-technical

users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the entity

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or

user-deﬁned

Number Estimated number of occurrences in the physical database

for the entity (the number of records)

Generate Indicates if the entity will generate a table in a PDM

An entity deﬁnition also includes the following properties, each with their

own respective property sheets that can be accessed independently of the

entity:

♦Attributes

♦Identiﬁers

♦Rules

Creating an entity

There are several ways to create an entity:

♦From a diagram

Chapter 3. Building Conceptual Data Models

♦From the Browser

♦From the list of entities

At creation, an entity has a default name including a number. This number is

assigned in the order of creation of objects.

+For more information on the different ways to create an entity, see

section Creating an object in chapter Managing objects in the

General

Features Guide

vTo create an entity from a diagram

1. Click the Entity tool in the Palette.

2. Click anywhere in the diagram.

The following symbol appears at the click position:

3. Click the Pointer tool.

Click the right mouse button.

You release the Entity tool.

4. Double-click the new entity symbol in the diagram to display the entity

property sheet.

5. Type a name and a code.

Deﬁning entities in a CDM

6. Click OK.

Modifying entity properties

You can modify the entity properties using the following methods:

♦From the entity property sheet

♦From the list of entities

+For more information on the different ways to modify the entity

properties, see section Modifying object properties in chapter Managing

objects in the

General Features Guide

Copying an entity

You can make a copy of an entity within the same model or between models.

When you copy an entity, the selections for the model options Unique code

and Allow reuse determine the way that identiﬁers and entity attributes are

copied and named.

The following rules apply to copied entities. The indicated selections for

Unique code and Allow reuse apply to the model that receives the copied

entity:

Chapter 3. Building Conceptual Data Models

Data item options

selected

Result of copying an entity

Unique Code

Allow Reuse

New entity with new name and code

New identiﬁer with new name code

Reuses other entity attributes

Unique Code only New entity with new name and code

New identiﬁer with new name and code

New attributes with new names and codes

Allow Reuse only New entity with new name and code

New identiﬁer with same name and code

Reuses other entity attributes

None New entity with new name and code

New identiﬁer with same name code

New entity attributes with same names and codes

vTo copy an entity within a model

1. Select an entity in the CDM.

2. Select Edit äCopy.

Select Edit äPaste.

Press CTRL and drag the entity to a new position in the diagram.

The new entity appears in the diagram

vTo copy an entity to a different model

1. Select an entity in a CDM.

2. Select Edit äCopy.

Click in the diagram of the target model.

Select Edit äPaste.

Press CTRL and drag the entity to the diagram of the target model.

The new entity appears in the diagram of the target model.

Deﬁning entities in a CDM

Modifying the entity display preferences

You can modify the following display preferences for an entity using the

Tools äDisplay Preferences command:

Preference Display description Examples

All attributes All attributes includ-

ing all identifying

attributes

Primary attributes Only entity attributes

that are primary iden-

tiﬁer attributes

Identifying at-

tributes

All attributes that are

deﬁned as identiﬁer

attributes for the en-

tity, including primary

identiﬁer attributes

Display limit (x) Number of entity

attributes shown de-

pending on deﬁned

value of x. In the

example, x is 5

Identiﬁers All identiﬁer attributes

for the entity are listed

at the bottom of the

entity symbol

Stereotype Stereotype of the en-

tity

—

Comment Comment of the entity.

When selected, all

other check boxes are

deselected, except for

Stereotype

Chapter 3. Building Conceptual Data Models

Preference Display description Examples

Data types Data type for each

entity attribute

Replace by Do-

mains

Domain for each entity

attribute. You can only

display domains when

the Data type check

box is selected

Domains Domain of an attribute

in an entity. This dis-

play option interacts

with the selection for

Data types. As a re-

sult, there are four

display options

See Display domain and data

type for options and examples

Mandatory The letter <

>be-

side each entity at-

tribute when it is

mandatory

Identiﬁer indicators <

>indicators next

to attributes that are

primary identiﬁer at-

tributes

>indicators next

to identiﬁer attributes

that are not primary

identiﬁer attributes

Stereotype (Entity

attributes)

Stereotype of the en-

tity attributes

—

Stereotype (Entity

identiﬁers)

Stereotype of the en-

tity identiﬁers

—

Deﬁning entities in a CDM

Display domain and data

type

You can display the domain of an attribute in the symbol of an entity. There

are four display options available:

Selected check box Result Symbol

Data type Displays only the

data type, if it exists

Domains Displays only the

domain, if it exists

Data types

Domains

Displays both data

type and domain, if

they exist

Data types

Replace by domains

If domain exists and

data type does not

exist, then displays

domain.

If domain does not

exist and data type

exists, then displays

data type.

Chapter 3. Building Conceptual Data Models

Deﬁning entity attributes in a CDM

Entity attributes are data items attached to an entity. When you generate a

Physical Data Model (PDM) from a Conceptual Data Model (CDM), entity

attributes are generated as columns in tables (entities).

Entity attribute properties

You can access entity attribute properties from the list of entity attributes or

from the entity property sheet.

Each entity attribute deﬁnition includes the following properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the entity attribute

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Data type Form of the data corresponding to the entity attribute, such as

numeric, alphanumeric, boolean, or others

Length Maximum length of the data type

Precision Maximum number of places after the decimal point

Domain Name of the associated domain

Primary

Identiﬁer

Indicates whether or not the entity attribute is the primary

identiﬁer of the current entity

Displayed When selected, the attribute is displayed in the entity symbol.

When cleared, the attribute is not displayed in the entity symbol

Mandatory Indicates whether or not this entity attribute must be assigned a

value

An entity attribute also includes the following properties:

Deﬁning entity attributes in a CDM

Property Description

Rules Business rules associated with entity attribute

Standard

Checks

Common data constraints

Additional

Checks

Customized rules for data validation

Notes Description associated with entity

Creating an entity attribute

There are several ways to create an entity attribute:

♦From a data item used as an entity attribute

♦From the attribute list for an entity

At creation, an entity attribute has a default name including a number. This

number is assigned in the order of creation of objects.

Using a data item as an entity attribute

You can use the data item as an entity attribute by attaching it to an entity.

This choice does not create a new data item. The resulting entity attribute

has the same code as the data item.

Reusing a data item as

an entity attribute

If you select Allow Reuse as a data item option, the same data item can be

an entity attribute for more than one entity. However, you cannot reuse a

data item that is an identiﬁer.

Reusing a data item does not create a new data item. The data item and the

corresponding entity attributes have the same code.

Setting data item options

You set data item options by selecting Tools äModel Options.

A new data item can be added by creating a new one or copying an existing

one as the basis for a new one. The following speciﬁc tools are available to

add data items:

Chapter 3. Building Conceptual Data Models

Tool Description/Effect of Model Options

Add Data Item This tool is only available if the Allow Reuse option is

selected in Model Options.

This tool displays all model data items. If you click this

tool and select a data item that is unused in the list of entity

attributes, a new data item is created and added to the list.

If you click this tool and select a currently used data item,

the data item is copied and used as the basis for a new data

item

Reuse Data

Item

No new unused data item can be created with this tool.

This tool displays all model data items. If you click this

tool and select a data item that is used in the list of entity

attributes, the data item is copied, added to the list and used

as the basis for a new data item

vTo use a data item as an entity attribute

1. Select the Attributes tab in the entity property sheet to display the

corresponding page.

It lists entity attributes associated with the entity.

2. Click the Add Data Item tool.

Deﬁning entity attributes in a CDM

A Selection box appears listing all of the available data items.

3. Select one or more data items.

4. Click OK.

The selected data items are added to the list of entity attributes.

5. Click OK in each of the dialog boxes.

Creating an entity attribute from the list of entity attributes

You can create an entity attribute directly in the list of entity attributes for an

entity. When you create an entity attribute, it is automatically added to the

list of data items. If you select Allow Reuse as a model option, the new data

item can be used as an entity attribute for other entities.

vTo create an entity attribute from the list of entity attributes

1. Select the Attributes tab in the entity property sheet to display the

corresponding page.

It lists entity attributes associated with the entity.

2. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line.

Chapter 3. Building Conceptual Data Models

3. Type an entity attribute name and an entity attribute code.

Automatically reuse a data item

If you select the data item options Allow Reuse and Unique Code and

you type the name of a data item that is already in use, you automatically

reuse the data item.

4. Click OK.

Attaching an entity attribute to a domain

If you attach an entity attribute to a domain, the domain supplies the data

type and related data characteristics. It may also indicate check parameters

and business rules.

vTo attach an entity attribute to a domain

1. Double-click an entity in the diagram to display its property sheet.

2. Click the Attributes tab to display the corresponding page.

It list entity attributes associated with the entity.

3. Click an entity attribute to deﬁne.

An arrow appears at the beginning of the line.

4. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The entity attribute property sheet opens to the General page.

Deﬁning entity attributes in a CDM

Opening property sheets at last accessed page

You can choose to open property sheets at the last accessed page by

selecting Tools äGeneral Options äDialog, and selecting the option

Keep Last Tab in the Property Sheets groupbox.

5. Select a domain from the Domain dropdown listbox at the bottom of the

dialog box.

Click the Ellipsis button at the end of the Domain dropdown listbox.

The list of domains appears.

Select a domain from the list.

Click OK.

6. Click OK.

You return to the Entity attributes page. In the Data Type column, the

data type of the domain replaces the data type previously deﬁned for the

entity attribute.

7. Click OK.

Selecting a data type for an entity attribute

There are two ways to select a data type for an entity attribute:

Chapter 3. Building Conceptual Data Models

♦Attach the entity attribute to a domain The domain dictates a

standard data type, a length, and a level of precision, as well as optional

check parameters.

♦Manually select the data type You select a standard data type along

with a length, a level of precision, and optional check parameters

About check parameters

Check parameters indicate data ranges and validation rule. You can attach

check parameters to entity attributes, data items, or domains.

vTo select a data type for an entity attribute

1. Double-click an entity in the diagram to display the entity property sheet.

2. Click the Attributes tab to display the corresponding page.

It lists entity attributes associated with the entity.

3. Click the Entity attribute to deﬁne.

An arrow appears at the beginning of the line.

4. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The entity attribute property sheet opens to the General page.

Deﬁning entity attributes in a CDM

5. Select a data type from the Data Type dropdown listbox.

Click the Question mark button at the end of the Data Type dropdown

listbox.

A list of standard data types supported by PowerDesigner appears.

Select the radio button corresponding to the data type you want to apply.

Undeﬁned data type

If you do not want to select a data type immediately, you can choose the

<UNDEF>data type.

6. Type the maximum number of characters for the data type in the Length

box.

7. If the data type can include values that take a decimal point, type the

number of places after the decimal point in the Precision box.

8. Click OK.

You return to the Entity attributes page. The change of data type appears

in the list of entity attributes.

Deﬁning an entity attribute as mandatory or optional

If an entity attribute is mandatory, every entity occurrence must have a value

for that entity attribute. If an entity attribute is optional, entity occurrences

do not have to have a value for that entity attribute.

By default all identiﬁers are mandatory.

vTo deﬁne an entity attribute as mandatory or optional

1. Double-click an entity in the diagram to display the entity property sheet.

2. Click the Attributes tab to display the corresponding page.

It lists entity attributes associated with the entity.

3. Click the Entity attribute to deﬁne.

An arrow appears at the beginning of the line.

4. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The entity attribute property sheet opens to the General page.

Chapter 3. Building Conceptual Data Models

5. Select the Mandatory check box at the bottom of the dialog box to make

the entity attribute mandatory.

Clear the Mandatory check box to make the entity attribute optional.

You cannot clear the Mandatory check box for an identiﬁer because it

must always be mandatory.

6. Click OK in each of the dialog boxes.

Deleting entity attributes

When you delete an entity or entity attributes, data item options determine

whether or not the corresponding data items are also deleted.

The following rules apply to deleted entity attributes:

Data item options Result of deleting an entity attribute

Unique Code

Allow Reuse

Deletes entity attribute

Does not delete corresponding data item

Unique Code only Deletes entity attribute

Does not delete corresponding data item

Allow Reuse only Deletes entity attribute

Deletes corresponding data item if it is not used by

another entity

None Deletes entity attribute

Deletes corresponding data item

Arranging a list of entity attributes

Each entity has its own list of entity attributes.

In a list of entity attributes, you can arrange items in any order. When you

generate a PDM, the order of entity attributes becomes the order of column

generation.

vTo arrange a list of entity attributes

1. Double-click an entity symbol to display the entity property sheet.

2. Click the Attributes tab to display the corresponding page.

Deﬁning entity attributes in a CDM

It lists the data items attached to the entity.

3. Select one or more entity attributes in the list.

4. Use the arrow buttons at the bottom left corner of the list to move the

items in the list.

5. Click OK.

Chapter 3. Building Conceptual Data Models

Deﬁning identiﬁers in a CDM

An identiﬁer is an entity attribute, or a combination of entity attributes,

whose values uniquely identify each occurrence of the entity. An identiﬁer is

the CDM equivalent of a primary key or an alternate key in a physical data

model (PDM).

Each entity must have at least one identiﬁer. If an entity has only one

identiﬁer, it is designated by default as the primary identiﬁer for the entity. A

primary identiﬁer is the main identiﬁer for an entity.

Designating an identiﬁer

You designate an identiﬁer from the Identiﬁers page of the entity property

sheet.

+For information on how to display identiﬁers in an entity symbol, see

section “Modifying the entity display preferences” on page 56.

You can also create an identiﬁer from the list of entity attributes: click the

Attributes tab in the entity property sheet, select one or more attributes to

include into the identiﬁer and click the Create Identiﬁer tool.

vTo designate an identiﬁer

1. Double-click an entity in the diagram to display the entity property sheet.

2. Click the Identiﬁers tab to display the corresponding page.

It lists identiﬁers deﬁned for the entity.

Deﬁning identiﬁers in a CDM

3. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line.

4. Type an identiﬁer name and code.

5. Click Apply.

The constraint name and code are committed.

6. Double-click the new identiﬁer name to display the identiﬁer property

sheet.

7. Click the Attributes tab to display the corresponding page.

It lists all entity attributes deﬁned for the identiﬁer. At identiﬁer creation,

the list is empty.

8. Click the Add Attributes tool.

A list of entity attributes deﬁned for the entity appears.

Chapter 3. Building Conceptual Data Models

9. Select check boxes for one or more entity attributes that you want to

designate as an identiﬁer.

10. Click OK in each of the dialog boxes.

Adding attributes to an entity identiﬁer

You can add attributes to an entity identiﬁer.

Deﬁning identiﬁers in a CDM

vTo add attributes to an identiﬁer

1. Click the Attributes tab in the identiﬁer property sheet to display the

corresponding page.

It lists the attributes currently deﬁned for the identiﬁer.

2. Click the Add Attributes tool.

A list of entity attributes deﬁned for the entity appears.

3. Select check boxes for one or more entity attributes that you want to

designate as an identiﬁer.

4. Click OK in each of the dialog boxes.

Designating a primary identiﬁer

Aprimary identiﬁer is an identiﬁer that has been designated as the main

identiﬁer for the entity. It generates a primary key in a PDM.

vTo designate a primary identiﬁer

1. Double-click an entity in the diagram to display the entity property sheet.

2. Click the Identiﬁers tab to display the corresponding page.

It lists the Identiﬁers deﬁned for the entity.

3. Select an identiﬁer from the list.

An arrow appears at the beginning of the line.

Chapter 3. Building Conceptual Data Models

4. Click the Property tool.

Double-click the arrow at the beginning of the line.

The identiﬁer property sheet appears.

5. Select the Primary Identiﬁer check box.

6. Click OK.

You return to the Identiﬁers page. The P column is selected for the new

primary identiﬁer.

Item not visible in list

To make an item visible in a list, click the Customize Columns and

Filter tool in the list toolbar, select the appropriate check box from the

list of ﬁlter options that appears, and click OK.

7. Click OK.

Modifying an identiﬁer name or code from the list

You can modify an identiﬁer name and code using the following methods:

♦From the identiﬁer property sheet accessible from the entity property

sheet

Deﬁning identiﬁers in a CDM

♦From the list of identiﬁers

+For more information on the different ways to modify the identiﬁer

properties, see section Modifying object properties in chapter Managing

objects in the

General Features Guide

Chapter 3. Building Conceptual Data Models

Deﬁning relationships in a CDM

A relationship is a link between entities. For example, in a CDM that

manages human resources, the relationship Member links the entities

Employee and Team, because employees can be members of teams. This

relationship expresses that each employee works in a team and that each

team has employees.

An occurrence of a relationship corresponds to one instance of each of the

two entities involved in the relationship. For example,

the employee Martin

working in the Marketing team

is one occurrence of the relationship

Member.

Relationships and

association

Relationships are used in the Entity Relationship (ER) and IDEF1X

modeling methodologies. In PowerDesigner you can also use associations

used in the Merise methodology to link entities. You can use either

relationships or associations exclusively, or combine the two methodologies

in the same model.

+For more information on using associations, see section “Deﬁning

associations in a CDM” on page 95.

This section analyzes relationships in the Entity Relationship methodology,

for more information on IDEF1X, see section CDM Options in chapter

Conceptual Data Model Basics.

Relationship properties

You can double-click any relationship symbol in the diagram to display its

properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the relationship

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Entity1

Entity2

The two entities linked by the relationship

Deﬁning relationships in a CDM

Property Description

Generate Indicates to generate a reference in PDM

Cardinalities Contains data about cardinality as the number of instances of

one entity in relation to another entity

Creating a relationship

There are several ways to create a relationship between entities:

♦From a diagram

♦From the Browser

♦From the list of relationships

At creation, a relationship has a default name including a number. This

number is assigned in the order of creation of objects.

When you create a relationship from the Browser or from the list of

relationships, you must previously deﬁne source and destination objects for

the relationship.

+For more information on the different ways to create a relationship, see

section Creating an object in chapter Managing objects in the

General

Features Guide

vTo create a relationship from a diagram

1. Click the Relationship tool in the Palette.

2. Click inside the ﬁrst entity and while continuing to hold down the mouse

button, drag the cursor to a second entity. Release the mouse button

inside the second entity.

A relationship symbol appears between the two entities.

Dragging a relationship to a different entity

You change the entity at either end of a relationship by clicking the

relationship to select it, holding the CTRL key down, and dragging one

of the attach points to a different entity.

Chapter 3. Building Conceptual Data Models

3. Click the Pointer tool.

Click the right mouse button.

You release the Relationship tool.

4. Double-click the new relationship symbol in the diagram to display the

relationship property sheet. It displays the deﬁnition of the selected

relationship.

5. Type a relationship name and a relationship code.

Opening the property sheet of objects at ends

You can open the property sheet of the source and destination objects

by clicking the Entity 1 and Entity 2 buttons located in the upper part of

the ﬂow property sheet.

6. Type or select relationship properties as required in the tabbed pages.

Deﬁning relationships in a CDM

7. Click OK.

Displaying relationships from the entity property sheet

Relationships linked to an entity are also displayed in the entity property

sheet. You can display those relationships from the Relationships tabbed

page of the Dependencies page.

Creating a reﬂexive relationship

A reﬂexive relationship is a relationship between an entity and itself.

Example The reﬂexive relationship

Supervise

expresses that an employee (Manager)

can supervise other employees.

Getting neat relationship lines

To obtain clean lines with rounded corners when you create a reﬂexive

relationship, select Display Preferences äFormat äRelationship and

modify the Line Style with the appropriate type from the Corners dropdown

listbox.

vTo create a reﬂexive relationship

1. Click the Relationship tool in the Palette.

2. Click inside the ﬁrst entity and while continuing to hold down the mouse

button, drag the cursor to a space next to the entity.

3. Click the entity.

A relationship symbol loops back to the same entity.

Chapter 3. Building Conceptual Data Models

Entity dependencies

In the Dependencies page of the entity, you can see two identical occur-

rences of the relationship, this is to indicate that the relationship is reﬂexive

and serves as origin and destination for the link

Modifying relationship properties

You can modify the relationship properties using the following methods:

♦From the relationship property sheet

♦From the list of relationships

+For more information on the different ways to modify the relationship

properties, see section Modifying object properties in chapter Managing

objects in the

General Features Guide

Deﬁning a code option for relationships

You can deﬁne the following code option for relationships:

Option Result when selected Result when cleared

Unique code Each relationship has a

unique code

Different relationships can have

the same code

If you do not select Unique Code, two relationships can have the same code.

In this case, you differentiate the relationships by the entities they link.

Error message The following error message appears when the option you choose is

incompatible with the current CDM:

Error message Solution

Unique Code option could not be

selected because at least two re-

lationships have the same code:

relationship_code

Change the code of one relationship

Deﬁning relationships in a CDM

vTo deﬁne a code option for relationships

1. Select Tools äModel Options.

The Model Options dialog box opens to the Model Settings page.

2. Select the Unique Code check box in the Relationship groupbox to

require a unique code for each relationship.

Clear the Unique Code check box in the Relationship groupbox to allow

more than one relationship to have the same code.

3. Click OK.

Deﬁning cardinality for relationships

Cardinality indicates the number of instances (none, one, or many) of an

entity in relation to another entity. You can select the following values for

cardinality:

Chapter 3. Building Conceptual Data Models

Cardinality Symbol Description

One-to-one <1..1>One instance of the ﬁrst entity can correspond

to only one instance of the second entity

One-to-many <1..n>One instance of the ﬁrst entity can correspond

to more than one instance of the second entity

Many-to-one <n..1>More than one instance of the ﬁrst entity can

correspond to the same one instance of the

second entity

Many-to-many <n..n>More than one instance of the ﬁrst entity can

correspond to more than one instance of the

second entity

The Cardinalities page contains a groupbox for each direction of the

relationship. The title of the groupbox takes the following form:

’EntityA’to ’EntityB’

The following properties apply to each direction of the relationship:

Property Description

Dominant role In a One to One relationship, indicates to generate a

reference in the PDM for this direction of the relationship

only

Role name Text that describes the relationship of EntityA to EntityB

Dependent Indicates that each instance of the EntityA is identiﬁed by

an instance of EntityB

Mandatory Indicates that each instance of the EntityA requires an

instance of the EntityB

Cardinality Maximum and minimum number of instances of EntityA

in relation to EntityB (if mandatory, at least 1). You can

indicate the following cardinalities:

0..1

0..n

1..1

1..n

Termination points In a diagram, termination points indicate cardinality at each end of a

relationship. A termination with a single contact point denotes a cardinality

Deﬁning relationships in a CDM

of one. A termination with three contact points denotes a cardinality of

many.

Termination point Cardinality

One

Many

+For more information on IDEF1X cardinality notation, see section CDM

options in chapter Conceptual Data Model Basics.

vTo deﬁne cardinality

1. Double-click the relationship to display the relationship property sheet.

It displays the deﬁnition of the selected relationship.

2. Click the Cardinalities tab to display the corresponding page.

3. Select one of the cardinality radio buttons.

4. Click OK.

Example The Cardinalities page below indicates that an employee must belong to one

and only one division, while a division must include one or more employees.

Chapter 3. Building Conceptual Data Models

Deﬁning a mandatory relationship

The property Mandatory indicates whether the relationship between entities

is mandatory or optional. You deﬁne options from the point of view of both

entities in the relationship.

Termination points In the resulting relationship symbol, a bar represents a mandatory

relationship. A circle represents an optional relationship.

Deﬁning relationships in a CDM

Termination

point

Existence Cardinality Description

Mandatory One Must exist one and only one

Mandatory Many Must exist one or more

Optional One May exist one, or none

Optional Many May exist one or more, or

none

+For more information on IDEF1X existence notation, see section CDM

options in chapter Conceptual Data Model Basics.

vTo deﬁne a mandatory relationship

1. Double-click the relationship symbol to display the relationship property

sheet.

2. Click the Cardinalities tab to display the corresponding page.

3. Select the Mandatory check box in one or both of the groupboxes

corresponding to a relationship direction.

4. Click OK.

Example The Cardinalities page below indicates that the subcontract relationship is

optional from customer to project, and mandatory from project to customer.

Each project must have a customer, while each customer does not have to

have a project.

Chapter 3. Building Conceptual Data Models

Deﬁning a dependent relationship

In a dependent relationship, one entity is partially identiﬁed by another.

Each entity must have an identiﬁer. In some cases, however, the attributes of

an entity are not sufﬁcient to identify an occurrence of the entity. For these

entities, their identiﬁers incorporate the identiﬁer of another entity with

which they have a dependent relationship.

Example An entity named Task has two entity attributes, TASK NAME and TASK

COST. A task may be performed in many different projects and the task cost

will vary with each project. To identify each occurrence of TASK COST the

unique Task entity identiﬁer is the compound of its

Task name

entity

attribute and the

Project number

identiﬁer from the Project entity.

Many to many relationship

A many-to-many relationship cannot be a dependent relationship.

Termination points In the resulting model, a triangle just before the termination point of the

relationship indicates a dependent relationship. The triangle points away

Deﬁning relationships in a CDM

from the dependent entity.

For example, here Entity B depends on Entity A.

The bar indicates that the relationship in not only dependent, but also

mandatory. The single contact point indicates the one-to-one cardinality of

the relationship. In this case, for each occurrence of Entity B there must be

only one occurrence of Entity A.

The tip of the triangle shown above has a bar to note a mandatory

relationship: every occurrence of Entity A requires an occurrence of Entity

+For more information on IDEF1X notation, see section CDM options in

chapter Conceptual Data Model Basics.

vTo deﬁne a dependent relationship

1. Double-click the relationship symbol to display the relationship property

sheet.

It displays the deﬁnition of the selected relationship.

2. Click the Cardinalities tab to display the corresponding page.

3. Select or clear the Dependent check box in each groupbox corresponding

to a relationship direction.

4. Click OK.

Example The property sheet below shows that the Task entity is dependent on the

Project entity.

Chapter 3. Building Conceptual Data Models

The relationship pictured here expresses this dependency.

The circle at the tip of the triangle indicates that occurrences of the Project

entity do not require an occurrence of the Task entity. But an occurrence of

the Task entity requires an occurrence of the Project entity on which it

depends.

Deﬁning a dominant relationship

In a one-to-one relationship, you can deﬁne one direction of the relationship

as dominant. If you deﬁne a dominant direction, the one-to-one relationship

generates one reference in the PDM. The dominant entity becomes the

parent table. If you do not deﬁne a dominant direction, the one-to-one

relationship generates two references.

Deﬁning relationships in a CDM

vTo deﬁne a dominant relationship

1. Double-click a relationship symbol in the diagram to display the

relationship property sheet.

It displays the deﬁnition of the selected relationship.

2. Click the Cardinalities tab to display the corresponding page.

3. Select the One to One check box.

4. Select the direction for the dominance from the Dominant Role

dropdown listbox.

5. Click OK.

Example For example, in the property sheet below, the Author to Picture direction is

dominant in the relationship.

The relationship pictured here shows the one-to-one relationship.

Chapter 3. Building Conceptual Data Models

In a PDM, this relationship generates the following reference: Author is the

parent table, and its primary key migrates to the Picture table as foreign key.

Changing a relationship into an associative entity

You can transform a relationship into an associative entity linked by two

relationships. Next, you can attach entity attributes to this associative entity,

that you could not attach to the relationship.

The associative entity gets the name and code of the relationship. The two

new relationships handle cardinality properties.

vTo change a relationship into an associative entity

1. Right-click a relationship symbol.

The relationship contextual menu appears.

2. Select Change to Entity äStandard from the contextual menu.

Customizing entity wizard

You can also select Change to Entity äWizard from the contextual

menu. A step by step wizard takes you through a more detailed

procedure for deﬁning an associative entity.

An associative entity with two relationships replaces the relationship.

The associative entity takes the name of the original relationship.

Creating an associative entity using the Change to Entity Wizard

You can use the Change to Entity wizard to transform a relationship into an

associative entity linked by two relationships.

You create the associative entity in three stages. Each stage corresponds to a

page in the wizard process. You move through each stage by clicking the

Next button.

You can enter the following information for each stage of the wizard:

Deﬁning relationships in a CDM

Stage Description

Customizing

entity

You type the name and code for the new entity. You can also

type a description in the Comment box

Customizing

Relationship

(New entity

to ﬁrst entity)

You type the name and code for the relationship that will

be created between the ﬁrst entity and the new entity. The

ﬁrst entity is deﬁned as Entity 1 in the property sheet for the

original relationship. You can also enter a role name for the

relationship and a cardinality value

Customizing

Relationship

(New entity

to second

entity)

You type the name and code for the relationship that will be

created between the new entity and the second entity. The

second entity is deﬁned as Entity 2 in the property sheet for

the original relationship. You can also enter a role name for

the relationship and a cardinality value

vTo create an associative entity using the Change to Entity Wizard

1. Right-click a relationship symbol.

A contextual menu appears.

2. Select äChange to Entity äWizard to display the Customizing Entity

page.

3. Type an entity name and an entity code.

4. Click Next.

The Customizing Relationship page appears.

5. Fill in details for the ﬁrst entity to new entity relationship.

6. Click Next.

The second Customizing Relationship page appears.

7. Fill in details for the new entity to second entity relationship.

8. Click Finish.

The associative entity with two relationships replaces the relationship.

Sorting the list of relationships

You can sort the list of relationships alphabetically or in reverse alphabetical

order by any list property.

The listed order is indicated by an arrowhead that appears at the end of the

column heading for the property as follows:

Chapter 3. Building Conceptual Data Models

Arrow type Listed order

Down arrow Alphabetically

Up arrow Reverse alphabetically

For example, when you click the column heading Name, the relationships

are listed by relationship name alphabetically when the down arrow is

indicated, and in reverse order when the up arrow is indicated.

Item not visible in list

To make an item visible in a list, click the Customize Columns and Filter

tool in the list, and from the list of ﬁlter options that appears, select the

appropriate item check box and click OK.

vTo sort the list of relationships

1. Select Model äRelationships to display the list of relationships.

2. Click a column header.

The listed references are ordered by the indicated property.

3. Click OK.

Relationship examples

This section shows the graphic representation of various relationship

properties.

One-to-many relationship Description

Each division may have zero

or more employees

Each employee may belong to

zero or one division

Each division must have one or

more employees

Each employee may belong to

zero or one division

Each division may have zero

or more employees

Each employee must belong to

one and only one division

Deﬁning relationships in a CDM

One-to-many relationship Description

Each division must have one or

more employees

Each employee must belong to

one and only one division

Each division may have zero

or more employees

Each employee must belong to

one and only one division

Each employee is identiﬁed

uniquely by division number

and employee number

Each division must have one or

more employees

Each employee must belong to

one and only one division

Each employee is identiﬁed

uniquely by division number

and employee number

One-to-one relationship Description

Each team works on zero or

one project

Each project is managed by

zero or one team

Each team works on one and

one project only

Each project is managed by

zero or one team

Each team works on zero or

one project

Each project is managed by

one and one team only

Chapter 3. Building Conceptual Data Models

Many-to-many relationship Description

Each division may have zero

or more employees

Each employee may belong to

zero or more divisions

Each division must have one or

more employees

Each employee may belong to

zero or more divisions

Each division may have zero

or more employees

Each employee must belong to

one or more divisions

Each division must have one or

more employees

Each employee must belong to

one or more divisions

Modifying the relationship display preferences

You can modify the following display preferences for a relationship using

the Tools äDisplay Preferences command:

Preference Display description

Name Name or code of the relationship*

Role Role of each direction in the relationship

Cardinality Minimum and maximum number of instances that the

ﬁrst entity can have relative to the second entity

Dominance Letter

on the dominant entity side of the relationship

Stereotype Stereotype of the relationship

*Displayed text depends on whether the Name or Code radio button is

selected.

Deﬁning relationships in a CDM

Modifying a relationship graphically

From the CDM graphic, you can modify a relationship as follows:

♦Bend a relationship symbol

♦Straighten a relationship symbol

♦Drag a relationship to a different entity

Bending a relationship symbol

vTo bend a relationship symbol

1. Press CTRL while you click a point on the relationship to insert an angle.

The point becomes a handle.

2. Release CTRL.

3. Drag and drop the handle to create the bend.

Straightening a relationship symbol

vTo straighten a relationship symbol

1. Click a relationship symbol that has angles.

Handles appear on the relationship symbol.

2. Press CTRL while you click a handle.

The handle and its angle disappear.

Dragging a relationship to a different entity

vTo drag a relationship to a different entity

1. Click a relationship.

2. Press CTRL while you drag one of its attach points to a different entity.

Chapter 3. Building Conceptual Data Models

Deﬁning associations in a CDM

An association is a connection between entities. In the Merise modeling

methodology an association is used to connect several entities that each

represents clearly deﬁned objects, but are linked by an event, which may not

be so clearly represented by another entity.

Each instance of an association corresponds to an instance of each entity

linked to the association.

Example Three entities VIDEOK7, CLIENT, and STORE contain video cassette,

client, and store information. They are linked by an association which

represents a video cassette rental (K7RENTAL). The K7RENTAL

association also contains the attributes DATE and STAFF_ID, which give

the date of the rental, and the identity of the staff member who rented out the

video cassette.

When you generate a PDM, K7RENTED is generated as a table with ﬁve

columns, STORE_ID,K7_ID, CLIENT_ID, DATE, and STAFF_ID.

Deﬁning associations in a CDM

In PowerDesigner you can use associations exclusively in your CDM, or use

both associations and relationships in the same model.

Association links An association is connected to an entity by an association link. An

Association Link symbolizes the role and the cardinality between an

association and an entity.

Association properties in CDM

You can double-click any association symbol in the diagram to display its

properties:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the association

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Number Estimated number of occurrences in the physical database for

the association (the number of records)

Generate Indicates if the association will generate a table in a PDM

Attributes Data item attached to an association

Rules Business rules associated with the association

Association link properties

You can double-click any association link symbol in the diagram to display

its properties:

Chapter 3. Building Conceptual Data Models

Property Description

Entity Entity connected by the association link

Associa-

tion

Association connected by the association link

Role Label indicating the role of the association link

Identiﬁer Indicates if the entity is dependent on the other entity

Cardinality Number of occurrences (one or many) of one entity to another

entity

Stereotype Sub-classiﬁcation used to extend the semantics of an object

without changing its structure; it can be predeﬁned or user-

deﬁned

Creating an association in a CDM

There are several ways to create an association:

♦From a diagram

♦From the Browser

♦From the list of associations

At creation, an association has a default name including a number. This

number is assigned in the order of creation of objects.

+For more information on the different ways to create an association, see

section Creating an object in chapter Managing objects in the

General

Features Guide

vTo create an association from a diagram

1. Click the Association Link tool in the Palette.

2. Click inside the ﬁrst entity and while continuing to hold down the mouse

button, drag the cursor to a second entity. Release the mouse button.

An association symbol is created between the two entities.

3. Double-click the new association symbol in the diagram to display the

association property sheet.

Deﬁning associations in a CDM

4. Type an association name and an association code.

5. Click OK.

Creating an association link

There are several ways to create an association link between an entity and an

association:

♦From a diagram

♦From the list of associations links

Creating an association link from a diagram:

vTo create an association link from a diagram

1. Click the Association Link tool in the Palette.

2. Click inside the ﬁrst entity and while continuing to hold down the mouse

button, drag the cursor to a second entity. Release the mouse button.

An association symbol with two associations links is created between the

two entities.

Chapter 3. Building Conceptual Data Models

3. Double-click one of the two associations links symbols in the diagram to

open the association link property sheet.

It displays the deﬁnition of the selected association link.

4. Type or select association link properties as required.

5. Click OK.

Creating an association link from the list of associations links

vTo create an association link from the list of associations links

1. Select Model äLinks to display the list of associations links.

2. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line. <None>is displayed by

default in the Entity and Association columns.

Deﬁning associations in a CDM

3. Click the down arrowhead in the Entity column and select an entity from

the dropdown listbox.

4. Click the Association column to display the down arrowhead and select

an association from the dropdown listbox.

5. Click the Cardinality of role column to display the down arrowhead and

select a cardinality from the dropdown listbox.

6. Click OK.

A symbol for this association link is created between the entity and the

association in the current diagram.

Creating a reﬂexive association in a CDM

A reﬂexive association is a relationship between an entity and itself.

Example The reﬂexive association Manager expresses that an employee (Manager)

can manage other employees.

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Chapter 3. Building Conceptual Data Models

vTo create a reﬂexive association

1. Click the Association Link tool in the Palette.

2. Click inside the entity and while continuing to hold down the mouse

button, drag the cursor to a space next to the entity.

3. Click the entity.

An association symbol loops back to the same entity.

Deﬁning cardinality for an association link

Cardinality indicates the number of occurrences (one or many) that one

entity has relative to another. You deﬁne the cardinality for each association

link between the association and the entity.

The cardinality of an association link can have the following values:

101

Deﬁning associations in a CDM

Cardinality Description

0,1 There can be zero or one occurrence of the association in

relation to one instance of the entity. The association is not

mandatory

0,n There can be zero or many occurrences of the association in

relation to one instance of the entity. The association is not

mandatory

1,1 One occurrence of the entity can be related to only one

occurrence of the association. The association is mandatory

1,n One occurrence of the entity can be related to one or many

occurrences of the association. The association is mandatory

You can change the default format of cardinalities from the registry:

HKEY_CURRENT_USER\Software\Sybase\PowerDesigner 11\ModelOptions\

Conceptual Options

CardinalityNotation=1 (0..1) or 2 (0,1)

vTo deﬁne cardinality for an association link

1. Double-click the association link between an association and an entity to

display the association link property sheet.

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Chapter 3. Building Conceptual Data Models

2. Select a cardinality from the Cardinality dropdown listbox.

3. Click OK.

You can repeat the procedure for each association link.

Deﬁning a dependent association in a CDM

In a dependent association, one entity is partially identiﬁed by another. Each

entity must have an identiﬁer. In some cases, however, the attributes of an

entity are not sufﬁcient to identify an occurrence of the entity. For these

entities, their identiﬁers incorporate the identiﬁer of another entity with

which they have a dependent association.

Example An entity named Task has two entity attributes, TASK NAME and TASK

COST. A task may be performed in many different projects and the task cost

will vary with each project. To identify each occurrence of TASK COST the

unique Task entity identiﬁer is the compound of its

Task name

entity

attribute and the

Project number

identiﬁer from the Project entity.

103

Deﬁning associations in a CDM

When you generate a PDM, the TASK table contains the PROJECT

NUMBER column as a foreign key, which is also a primary key column.

The primary key therefore consists of both PROJECT NUMBER and TASK

NAME columns.

Association link identiﬁers and associations

The same association can not have two identiﬁer association links.

vTo deﬁne a dependent association

1. Double-click an association link symbol to display the association link

property sheet.

2. Select the Identiﬁer check box.

3. Click OK.

The cardinality of the association link is enclosed in parenthesis to

indicate that the association link is an identiﬁer.

Changing an association into an associative entity

You can transform an association into an associative entity linked by two

associations. The associative entity gets the name and code of the

association. The two new associations handle cardinality properties.

Example Two entities PROJECT MANAGER and CONTRACTOR are linked by the

association WORKS ON PROJECT WITH:

You can represent this association with an associative entity:

The two new associations can be represented as follows:

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Chapter 3. Building Conceptual Data Models

vTo change an association into an associative entity

1. Right-click an association symbol.

The association contextual menu appears.

2. Select Change to Entity from the contextual menu.

An associative entity that is linked to two associations replaces the

original association. The associative entity takes the name of the original

association.

Creating an association attribute

There are several ways to create an association attribute:

♦From a data item used as an association attribute

♦From the attribute list for an association

At creation, an association attribute has a default name including a number.

This number is assigned in the order of creation of objects.

Using a data item as an association attribute

You can use a data item deﬁned in the model as an attribute for an

association.

Allow Reuse

If the model option Allow Reuse is not selected, you can not create an

association attribute by reusing an existing data item. In this case the Add

Data Items tool is not available.

105

Deﬁning associations in a CDM

vTo use a data item as an association attribute

1. Double-click the association in the diagram to display the association

property sheet.

2. Click the Attributes tab to display the corresponding page.

It lists attributes associated with the association.

3. Click the Add Data items tool.

A Selection box appears listing all of the available data items.

4. Select one or more data items.

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Chapter 3. Building Conceptual Data Models

5. Click OK.

The selected data items are added to the list of attributes for the

association.

6. Click OK in each of the dialog boxes.

Creating an association attribute from the list of association attributes

You can create an association attribute directly in the list of attributes for an

association. When you create an association attribute, it is automatically

added to the list of data items. If you select Allow Reuse as a model option,

the new data item can be used as an attribute for other associations or

entities.

vTo create an association attribute from the list of association at-

tributes

1. Double-click the association to display the association property sheet.

2. Click the Attributes tab to display the corresponding page.

It lists association attributes associated with the association.

3. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line.

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Deﬁning associations in a CDM

4. Type an association attribute name and an association attribute code.

Automatically reuse a data item

If you select the data item model options Allow Reuse and Unique

Code and you type the name of a data item that is already in use, you

automatically reuse the data item.

5. Click OK.

Modifying the association display preferences in a CDM

You can modify the following display preferences of an association using

the Tools äDisplay Preferences command:

Group box Preference Display description

Association Attributes Name or code of the association*

Display Limit Maximum number of attributes displayed in

symbol

Stereotype Stereotype of the association

Comment Comment of the association. When se-

lected, all other check boxes are deselected,

except for Stereotype

Association

attributes

Data types Data type of association attribute

Replace by

domains

Domain for each association attribute. You

can only display domains when the Data

types check box is selected

Domains Domain of each association attribute

Mandatory Letter

beside each mandatory association

attribute

Stereotype Stereotype of the association attributes

*Displayed text depends on whether the Name or Code radio button is

selected.

Display domain and data

type

You can display the domain and data types in the symbol of an association.

There are four display options available:

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Chapter 3. Building Conceptual Data Models

Selected checkbox Result Symbol

Data types Displays only the

data type, if it exists

Domains Displays only the

domain, if it exists

Data types

Domains

Displays both data

type and domain, if

they exist

Data types

Replace by domains

If domain exists and

data type does not

exist, then displays

domain.

If domain does not

exist and data type

exists, then displays

data type.

Moving text on a relationship symbol

When a relationship symbol displays text, the text position is based on the

position of handles. You can add a handle on the relationship symbol by

pressing CTRL while you click the symbol.

Modifying the association link display preferences

You can modify the following display preferences of an association link

using the Tools äDisplay Preferences command:

Preference Description

Role Displays the role of the association link

Cardinality Displays the cardinality of the association link

Stereotype Stereotype of the association link

109

Deﬁning inheritances in a CDM

Inheritance allows you to deﬁne an entity as a special case of a more

general entity. The entities involved in an inheritance have many similar

characteristics but are nonetheless different. The general entity is known as a

supertype (or parent) entity and contains all of the common characteristics.

The special case entity is known as a subtype (or child), entity and contains

all of the particular characteristics.

Between entities, it is also possible to deﬁne an inheritance link. In an

inheritance link, one or more subtype (or child) entities inherit, at the

physical level, all or part of the entity attributes carried by one supertype (or

parent) entity.

The Account entity below represents all the bank accounts in the

information system. It includes two subtypes: checking accounts and

savings accounts. The notion of inheritance represents the entities Checking

and Savings as specialized types of the parent entity Account.

Inheritance properties

You can double-click any inheritance symbol in the diagram to display its

properties:

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Chapter 3. Building Conceptual Data Models

Property Description

Name The name of the item which should be clear and mean-

ingful, and should convey the item’s purpose to non-

technical users

Code The technical name of the item used for generating code

or scripts, which may be abbreviated, and should not

generally include spaces

Comment Descriptive label for the inheritance link

Stereotype Sub-classiﬁcation used to extend the semantics of

an object without changing its structure; it can be

predeﬁned or user-deﬁned

Parent Name of the parent entity

Mutually exclu-

sive children

Indicates if only one child can exist for one occurrence

of the parent entity.

Complete Indicates that all instances of the parent entity (surtype)

must belong to one of the children (subtypes). For ex-

ample, entity Person has 2 sub-types Male and Female;

each instance of entity Person is either a male or a

female

An inheritance link deﬁnition also includes the following properties, which

are deﬁned on associated property sheets:

Property Description

Generation Group of properties that affect physical implementation

Children List of child entities

Notes Description associated with inheritance link

Rules Business rules attached to the inheritance link

Inheritance display Depending on the model notation, the inheritance symbol displays the

inheritance status:

111

Deﬁning inheritances in a CDM

IDEF1X E/R and Merise notation Description

Standard

— Mutually exclusive

inheritance

Complete inheritance

— Mutually exclusive and

complete inheritance

Creating an inheritance link

You can create an inheritance link graphically in the diagram by dragging

and dropping an inheritance link symbol from the child entity to the parent

entity using the Inheritance tool.

vTo create an inheritance link

1. Click the Inheritance tool in the Palette.

2. Click the child entity, while continuing to hold down the mouse button,

drag the cursor to the parent entity. Release the mouse button inside the

child entity.

The link appears between the two entities and has a half-circle in the

middle and an arrowhead that points to the parent entity.

3. If you want to create additional child entities for the same link, drag and

drop an inheritance link from the half-circle to the additional child entity.

The symbol links all the child entities to the parent.

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Dragging an inheritance link to a different child entity

You can change the child entity at the end of an inheritance link by

clicking the inheritance link and holding down CTRL as you drag one of

its attach points to a different entity.

4. Double-click the new link in the diagram to display the inheritance

property sheet.

5. Type an inheritance name and an inheritance code.

6. Click OK.

Adding a child entity to an inheritance link

You can add a child entity to an inheritance link.

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Deﬁning inheritances in a CDM

vTo add a child entity to an inheritance link

1. Double-click an inheritance symbol to display the inheritance property

sheet.

2. Click the Children tab to display the corresponding page.

3. Click the Add Children tool.

A selection box appears. It lists the entities available in the model.

4. Select one or more entities.

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5. Click OK.

The new entity is added to the list of child entities on the Children page.

6. Click OK.

The new child entity is linked to the inheritance symbol in the diagram.

Making inheritance links mutually exclusive

When an inheritance link is mutually exclusive between children, one

occurrence of the parent entity cannot be matched to more than one child

entity.

This information is for documentation only and has no impact in generating

the PDM.

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Deﬁning inheritances in a CDM

vTo make an inheritance link mutually exclusive

1. Double-click the inheritance link in the diagram to display the inheritance

link property sheet.

2. Select the Mutually Exclusive Children check box.

3. Click OK.

The mutually exclusive inheritance links display an X on the half-circle

symbol.

The inheritance link shown above is mutually exclusive. It means that an

account is either checking or savings, never both.

Generation mode properties

Generation mode deﬁnes the physical implementation of an inheritance

structure.

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Chapter 3. Building Conceptual Data Models

In the CDM, the generation mode indicates which entities in an inheritance

structure should correspond to tables in the PDM, as follows:

Generation mode Generates table(s)

corresponding to

Which have the following

properties

Generate parent Parent entity Inherits entity attributes of

each child entity

Is affected by child entity

relationships.

Contains reference to any

table which has a many-to-

one relationship with child

entity

Generate children

Inherit all attributes

Each child entity Inherits all entity attributes of

the parent entity

Generate children

Inherit only primary

attributes

Each child entity Inherits only the identiﬁer of

the parent entity

Primary keys for child tables

When you generate a child table, its primary key is the concatenation of the

child entity identiﬁer and the parent entity identiﬁer.

Deﬁning generation mode

You deﬁne the generation mode which speciﬁes the physical implementation

of an inheritance structure.

Generating specifying

attributes

In the case of parent only generation, you can choose to deﬁne a specifying

attribute to differentiate occurrences of a child.

+For more information on specifying attribute properties see section

“Specifying entity attribute properties” on page 118.

+For more information on deﬁning a specifying attribute, see section

“Deﬁning a specifying entity attribute” on page 120.

vTo deﬁne generation mode

1. Double-click the inheritance link in the diagram to display the inheritance

property sheet.

2. Click the Generation tab to display the corresponding page.

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Deﬁning inheritances in a CDM

3. Select Generate Parent.

Select Generate Children.

Select both Generate Parent and Generate Children.

4. If you selected Generate Children, do one of the following actions:

Click the Inherit All Attributes radio button.

Click the Only Primary Attributes radio button. Primary attributes are the

attributes deﬁned in the primary identiﬁer.

5. Click OK.

Specifying entity attribute properties

Aspecifying entity attribute is an entity attribute that is deﬁned for a

parent entity which differentiates occurrences of each child. It only applies

to parent only generation.

Example In the example below, the TITLE entity has two children,

NONPERIODICAL and PERIODICAL.

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Chapter 3. Building Conceptual Data Models

As only the parent table TITLE will be generated in a PDM, a specifying

entity attribute PERIODICAL is deﬁned for the inheritance link to

differentiate between the two child entities.

In the PDM, each of the child entity attributes will generate columns in the

table TITLE, however the specifying entity attribute PERIODICAL will

generate a corresponding column PERIODICAL. The values of this column

indicate whether an instance of TITLE is a periodical or not.

You can specify the following properties for a specifying entity attribute:

Property Description

Name The name of the item which should be clear and meaningful,

and should convey the item’s purpose to non-technical users

Code The technical name of the item used for generating code or

scripts, which may be abbreviated, and should not generally

include spaces

Comment Descriptive label for the specifying entity attribute

Data type Data type that you want to apply to the specifying entity

attribute

Length Maximum length of the data type

Precision Number of places after the decimal point, for data values that

can take a decimal point

Domain Name of the associated domain

Mandatory Indicates whether or not the specifying entity attribute must be

assigned a value

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Deﬁning inheritances in a CDM

Deﬁning a specifying entity attribute

You deﬁne a specifying entity attribute only in the case of parent only

generation. In a PDM the specifying attribute differentiates occurrences of

each child. There are several ways to create a specifying attribute:

♦From a data item used as a specifying attribute

♦From the specifying attribute list for an inheritance

Using a data item as a specifying attribute

You can use a data item deﬁned in the model as an specifying attribute.

Allow Reuse

If the model option Allow Reuse is not selected, you can not create an

specifying attribute by reusing an existing data item. In this case the Add

Data Item tool is not available.

vTo use a data item as a specifying attribute

1. Double-click an inheritance symbol to display the inheritance property

sheet.

2. Click the Generation tab to display the corresponding page.

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3. Select the Generate Parent check box.

4. Clear the Generate Children check box.

5. Click the Add Data items tool.

A Selection box appears listing all of the available data items.

6. Select a data item.

7. Click OK.

The selected data item is added to the list of specifying attributes for the

inheritance.

8. Click OK.

Using the Generate option

The option Generate Children generates a table for each child in the

inheritance. If you do not select Generate Children, you can control the

generation of child tables using the option Generate in the property sheet

of each child entity.

Creating a specifying attribute from the specifying attributes list for an inheritance

You can create a specifying attribute directly in the list of specifying

attributes for an inheritance. When you create an specifying attribute, it is

automatically added to the list of data items. If you select Allow Reuse as a

model option, the new data item is available to be re-used as an attribute for

an entity, association, or inheritance.

vTo create a specifying attribute from the specifying attributes list

for an inheritance

1. Double-click the inheritance symbol to display the inheritance property

sheet.

2. Click the Generation tab to display the corresponding page.

3. Select the Generate Parent check box.

4. Clear the Generate Children check box.

5. Click a blank line in the list.

Click the Add a Row tool.

An arrow appears at the beginning of the line.

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Deﬁning inheritances in a CDM

6. Type a specifying attribute name and a specifying attribute code.

7. Click Apply.

You commit the creation of the new attribute.

8. Click the new attribute line.

An arrow appears at the beginning of the line.

9. Click the Properties tool.

Double-click the arrow at the beginning of the line.

The attribute property sheet appears.

10. Type or select attribute properties.

11. Click OK.

Modifying the inheritance display preferences

You can modify the following display preference of an inheritance using the

Tools äDisplay Preferences command:

Preference Description

Name Displays the name of the inheritance

Stereotype Stereotype of the inheritance

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Deﬁning check parameters in a CDM

Check parameters are set of conditions which data must satisfy to remain

valid.

There are three types of check parameters:

Parameter type Description Can be at-

tached to

Standard check

parameters

Common data constraints which

deﬁne a data range. For example

minimum and maximum values for a

column

Entity attributes

Domains

Additional check

parameters

SQL expression deﬁning a data con-

straint using the %MINMAX%,

%LISTVAL%, and %RULES% vari-

ables that are instantiated with stan-

dard parameter values

Entity attributes

Domains

Validation rule Business rule that is deﬁned as a

server expression, and is attached to

one of the following listed objects

Entities

Entity attributes

Domains

Setting standard parameters for objects in a CDM

Standard parameters indicate common data constraints. The following table

lists standard parameters:

Parameter Description

Minimum Lowest acceptable numeric value

Maximum Highest acceptable numeric value

Default Value assigned in absence of an expressly entered value

Unit Standard measure

Format Data format (for example, 9999.99)

Lowercase Forces all alphabetical characters to lowercase

Uppercase Forces all alphabetical characters to uppercase

Cannot Modify Protects from changes, results in a non-modiﬁable column

in the physical data table

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Deﬁning check parameters in a CDM

Parameter Description

List of Values Authorized values

Label String that identiﬁes an authorized value in the list

vTo set standard parameters for objects in a CDM

1. Click the Standard Checks tab in the property sheet of a domain or an

entity attribute to display the corresponding page.

2. Type your choice of Standard Parameters.

3. Click OK.

Deﬁning additional check parameters for objects in a CDM

You can write an SQL statement using the following standard variables

deﬁned as standard check parameters and validation rules:

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Chapter 3. Building Conceptual Data Models

Variable Description

%MINMAX%, Minimum and maximum values deﬁned in Values group-

box on Standard Checks page

%LISTVAL% Customized values deﬁned in List Values groupbox on

Standard Checks page

%RULES% Validation rule expression deﬁned on Expression page of

the Rules property sheet

You deﬁne additional check parameters for data constraints where standard

check parameters are not sufﬁcient.

Example An entity in a data model for a clothing shop may contain check parameters

deﬁned for an entity attribute SIZE, which depend on the check parameters

deﬁned for another entity attribute COUNTRY, as clothing size for a skirt in

France may be different from the same size in the United States.

In this case an expression is required to create a constraint which uses check

parameters deﬁned for both entity attributes.

vTo deﬁne additional check parameters for objects

1. Click the Additional Checks tab in the property sheet of a domain or an

entity attribute to display the corresponding page.

2. Type SQL expression using the variables %MINMAX%, %LISTVAL%,

and %RULES%.

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Deﬁning check parameters in a CDM

3. Click OK.

Using a validation rule in check parameters in a CDM

A validation rule is a rule that validates data based on a corresponding

business rule. A validation rule can be generated as a check parameter when

the following conditions apply:

♦Validation rule is attached to an entity, entity attribute, or domain

♦Validation rule is deﬁned as a server expression

At generation, validation rule variables are instantiated with the following

values:

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Chapter 3. Building Conceptual Data Models

Variable Value

%COLUMN% Code of the column to which the business rule applies

%DOMAIN% Code of the domain to which the business rule applies

%TABLE% Code of the table to which the business rule applies

%MINMAX% Minimum and maximum values for the entity attribute

or domain

%LISTVAL% List values for the entity attribute or domain

%RULES% Server validation rules for the entity attribute or domain

+For more information on deﬁning business rules, see section Deﬁning a

business rule in a CDM in chapter Using Business Rules in a CDM.

vTo use a validation rule in check parameters

1. Click the Rules tab in the property sheet of a domain, an entity or an

entity attribute to display the corresponding page.

2. Click the Add Rules tool.

A list appears displaying the available business rules in the model.

3. Select a business rule in the list.

4. Click OK in each of the dialog boxes.

Validation rule expressions

You must click the Rules button to modify the expression attached to a

validation rule. You can also modify validation rule expressions from

the list of business rules, by clicking the Deﬁne button.

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CHAPTER 4

Working with Conceptual Data Models

About this chapter This chapter describes how to check the validity of a Conceptual Data Model

and how you can import an ERwin model into a CDM. It also gives

information on how you can open a ProcessAnalyst Model (PAM) into a

CDM.

Contents Topic: page

Checking a CDM 130

Object parameters veriﬁed by Check model 136

Opening a PAM into a CDM 151

129

Checking a CDM

You can use the Check Model to check the validity of a CDM at any time.

A valid CDM conforms to the following rules:

♦Each object name must be unique

♦Each entity must have at least one attribute

♦Each relationship must be attached to at least one entity

CDM check options

When you check a CDM, you can deﬁne levels of severity for problems that

Check model ﬁnds and have certain problems automatically corrected.

Levels of problem

severity

You can set a level of problem severity for each object parameter that is

veriﬁed by the Check model. This severity level can depend on the degree of

normalization that you want to achieve in a your model.

When you check a CDM, you can display an invalid parameter with one of

two types of messages, depending on the degree of problem severity you

assigned to that parameter:

Message Description

Error Major problem that impedes database generation

Warning Minor problem or recommendation

Automatic correction You can choose to have certain problems corrected automatically by

PowerDesigner. Automatic correction primarily ﬁxes non-unique names in

the CDM. However, before using automatic correction, make sure you

understand how it will affect your model.

+As automatic correction is not available for most object parameters, they

must be corrected manually.

+For more information on manual and automatic correction, see “Object

parameters veriﬁed by Check model” on page 136.

Setting problem severity

and automatic correction

You can use the following tools from the Check Model Parameters dialog

box to set either an error or warning level of problem severity, and also if

you want PowerDesigner to automatically correct an error:

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Chapter 4. Working with Conceptual Data Models

Tool Indicates Description

Error Indicates a major problem that impedes database

generation

Warning Indicates a minor problem or recommendation

Automatic

correction

Indicates that PowerDesigner will correct the

problem automatically

CDM object selection in the Check Model

You select objects to be checked from the Selection page of the Check

Model Parameters dialog box (Tools äCheck Model).

You can list all objects created in the current model, current package, or

sub-packages by selecting the Include Sub-Objects tool.

You have the following selection options:

Parent

object

Include Sub-Objects se-

lected

Include Sub-Objects not se-

lected

Model All objects created in model

including those in packages

and sub-packages

All objects created in model

except those in packages and

sub-packages

Package All objects created in pack-

age including those in sub-

packages

All objects created in package

except those in sub-packages

Selecting objects in the diagram

If you graphically select objects in your diagram before starting the Check

Model, they can be automatically selected for veriﬁcation by the Check

Model by clicking the Use Graphical Selection tool in the Selection page

toolbar.

Checking a global CDM

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Checking a CDM

vTo check a global CDM

1. Select Tools äCheck Model.

Right-click the diagram background and select Check Model from the

contextual menu.

The Check Model Parameters dialog box opens to the Options page.

2. Expand an object parameter node.

The object parameters which are veriﬁed by the Check Model are

displayed with the symbols indicating a degree of problem severity.

3. If you want to change a degree of problem severity, select the object

parameter and then select either the Error or Warning tool.

The symbol changes to the appropriate severity level.

4. If you want PowerDesigner to automatically correct a problem, select the

object parameter and then select the Automatic Correction tool.

The Automatic Correction symbol appears superimposed on the Error or

Warning symbol for that object parameter.

5. Click the Selection tab to display the corresponding page.

6. Select a model from the dropdown list at the top of the dialog box.

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Chapter 4. Working with Conceptual Data Models

7. Click an object tab.

The corresponding object page displays all the objects in the current

CDM.

8. Select check boxes for objects that you want to be checked.

Clear check boxes for objects that you do not want to be checked.

Selecting all or clearing all check boxes

You can select all object check boxes by clicking the Select All tool.

You can clear all object check boxes by clicking the Deselect All tool.

9. Click OK.

The Check Model Result List dialog box displays errors and warnings,

based on your choice of check options.

Dockable result window

When you right-click an object parameter a menu appears listing correction

options. Among these, you can also select options to clear, dock or hide

the result window.

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Checking a CDM

Displaying previously applied check options

If you click the Apply button in the Check Model Parameters dialog box, all

error and warning selections are stored in memory.

vTo display errors and warnings selected in the last check

1. Select Tools äCheck Model.

The Check Model Parameters dialog box opens to the Options page. The

object parameters are displayed with the Error or Warning icons selected

in the last check.

Making corrections based on CDM check results

You can use the Check Model to locate and correct problems in the CDM.

You can choose one of the following correction options from the Check

toolbar:

Symbol Option Description

Manual correction Displays property sheet of problem object

Display help Displays description of the error and sugges-

tion for correction

Check again Checks selected object parameter, normally

after a correction has been done

Automatic correc-

tion

Automatically corrects certain errors

Navigating in the error list The Check tool bar also contains navigation tools that you can use to move

to the ﬁrst, previous, next, or last errors that are listed. You can also navigate

in the list of errors by right-clicking an object parameter and selecting Go To

First error, Previous error, Next error, or Last error from the contextual

menu.

Contextual menu

When you right-click an object parameter in the Result List to open

a contextual menu that lists the following correction options: Correct

(manual correction), Help (error description), Check again, and Automatic

Correction. You can also select options to navigate among errors, clear the

Result List, dock and hide the result window.

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Chapter 4. Working with Conceptual Data Models

Making manual corrections to a CDM

vTo make manual corrections to a CDM

1. Select an object parameter from the Result List.

2. Right-click the object parameter and select Correct from the contextual

menu.

The object property sheet appears.

3. Select the appropriate tab and make the necessary correction.

4. Close the property sheet.

5. Re-select the object parameter.

6. Right-click the object parameter and select Check again from the

contextual menu.

Verify that the problem has been corrected.

Making automatic corrections to a CDM

vTo make automatic corrections to a CDM

1. Select an object parameter, from the Result List.

2. Right-click the object parameter and select Automatic Correction from

the contextual menu.

3. Right-click the object parameter and select Check again from the

contextual menu.

Verify that the problem has been corrected.

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Object parameters veriﬁed by Check model

The Check Model veriﬁes the validity of the following CDM objects.

When errors are encountered during a check model, corrections can be made

manually or automatically. Manual corrections depend on how you are using

your model.

Use the Help command to select object control options

When you right-click a CDM object control in the Check Model Parameters

page, a menu appears listing several options. The Help command opens

a contextual help page explaining the checks performed for the selected

object type.

Business Rule check in a CDM

During a business rule check, the following object controls are made.

Business rule name and code uniqueness

A model cannot contain two business rules with identical name and/or code.

Manual correction Automatic correction

Modify the duplicated business

rule name/code

Modiﬁes the business rule name/code of

a selected object by appending a number

to its current name

Unused business rule

The business rule you have created is not used in the model.

Manual correction Automatic correction

Apply the business rule to an

object in the model

—

Package check

During a package check, the following object controls are made.

Circular dependency

A circular dependency occurs when an entity depends on another and so on

until a dependency loop is created between entities. A package cannot

contain circular dependencies.

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Chapter 4. Working with Conceptual Data Models

Manual correction Automatic correction

Clear the Dependent check box

for the link or delete an inheri-

tance link

—

Circularity with mandatory links

A circular dependency occurs when an entity depends on another and so on

until a dependency loop is created between entities through mandatory links.

Manual correction Automatic correction

Clear the Mandatory parent

check box or delete a depen-

dency on a relationship

—

Shortcut code uniqueness

Two shortcuts with the same code cannot be in the same namespace.

Manual correction Automatic correction

Change the code of one of the

shortcuts

—

Shortcut potentially generated as child table of a reference

The package should not contain associations or relationships with an

external shortcut as child entity. Although this can be tolerated in the CDM,

the association or relationship will not be generated in a PDM if the external

shortcut is generated as a shortcut.

Manual correction Automatic correction

Modify the design of your model

in order to create the association or

relationship in the package where

the child entity is deﬁned

—

Domain check

During a domain check, the following object controls are made.

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Object parameters veriﬁed by Check model

Domain name and code uniqueness

Domain names and codes cannot be used more than once in the model.

Manual correction Automatic correction

Modify the duplicate domain

name/code

Modiﬁes the domain name/code of a

selected object by appending a number

to its current name

Inconsistency in check parameters

The values entered in the check parameters page are inconsistent for numeric

and string data types: default does not respect minimum and maximum

values, or default does not belong to list of values, or values in list are not

included in minimum and maximum values, or minimum is greater than

maximum value. Check parameters must be deﬁned consistently.

Manual correction Automatic correction

Modify default, minimum, maxi-

mum or list of values in the check

parameters page

—

Data type precision and length

The data type precision should not be greater than or equal to the length.

Manual correction Automatic correction

Make the data type length greater

than or equal to the precision

—

Undeﬁned data type

Undeﬁned data types for domains exist. To be complete, a model should

have all its domain data types deﬁned.

Manual correction Automatic correction

While undeﬁned data types are

tolerated, you must select data

types for currently undeﬁned data

types before you can generate a

PDM

—

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Chapter 4. Working with Conceptual Data Models

Non-valid data type

Invalid data types for domains exist. To be complete, a model should have

all its domain data types correctly deﬁned.

Manual correction Automatic correction

While tolerated, you must select

valid data types for currently

non-valid data types to generate

the PDM

—

Data item check

During a data item check, the following object controls are made.

Data item name and code uniqueness

Data item names and codes cannot be used more than once in the namespace.

Manual correction Automatic correction

Modify the duplicate data item

name/code

Modiﬁes the data item name/code of a

selected object by appending a number

to its current name

Unused data items

There are unused data items. These are useless for PDM generation.

Manual correction Automatic correction

To use a data item, add it to an

entity. If you do not need an

unused data item, delete it to

allow PDM generation

—

Re-used data items

There are entities using the same data items. This can be tolerated if you

deﬁned this check as a warning.

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Object parameters veriﬁed by Check model

Manual correction Automatic correction

Take care to ensure consistency

when deﬁning data item proper-

ties

—

Data item and domain divergence

There is a divergence between data items and associated domains. This can

be tolerated if you deﬁned this check as a warning.

Manual correction Automatic correction

Ensure consistency when deﬁn-

ing data item properties

Restores divergent attributes from do-

main to data items (domain values over-

write data item values)

Inconsistency in check parameters

The values entered in the check parameters page are inconsistent for numeric

and string data types: default does not respect minimum and maximum

values, or default does not belong to list of values, or values in list are not

included in minimum and maximum values, or minimum is greater than

maximum value. Check parameters must be deﬁned consistently.

Manual correction Automatic correction

Modify default, minimum, maxi-

mum or list of values in the check

parameters page

—

Data type precision and length

The data type precision should not be greater than or equal to the length.

Manual correction Automatic correction

Make the data type length greater

than or equal to the precision

—

Undeﬁned data type

Undeﬁned data types for data items exist. To be complete, a model should

have all its data items data types deﬁned.

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Chapter 4. Working with Conceptual Data Models

Manual correction Automatic correction

While undeﬁned data types are

tolerated, you must select data

types for currently undeﬁned data

types before you can generate a

PDM

—

Non-valid data type

Invalid data types for data items exist. To be complete, a model should have

all its data types for data items correctly deﬁned.

Manual correction Automatic correction

While tolerated, you must select

valid data types for currently

non-valid data types to generate

the PDM

—

Entity check

During an entity check, the following object controls are made.

Entity name and code uniqueness

Entity names and codes cannot be used more than once in the namespace.

Manual correction Automatic correction

Modify the duplicate entity

name/code

Modiﬁes the entity name/code of a se-

lected object by appending a number to

its current name

Entity name and code length

The entity name and code length are limited to a maximum length of 254

characters speciﬁed in the naming conventions of the model options.

Manual correction Automatic correction

Modify the entity name/code

length to meet this requirement

Truncates the entity name/code length

to the maximum length speciﬁed in the

naming conventions

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Object parameters veriﬁed by Check model

Existence of attributes

An entity must always contain at least one attribute.

Manual correction Automatic correction

Add an attribute to the entity or

delete the entity

—

Number of serial types greater than 1

An entity cannot have more than one serial type attribute. Serial types are

automatically calculated values.

Manual correction Automatic correction

Change the types of the appropri-

ate entity attributes to have only

one serial type attribute

—

Existence of identiﬁers

An entity must contain at least one identiﬁer.

Manual correction Automatic correction

Add an identiﬁer to the entity or

delete the entity

—

Existence of relationship or association link

An entity must have at least one relationship or association link.

Manual correction Automatic correction

Add a relationship or an associ-

ation link to the entity or delete

the entity

—

Redundant inheritance

An entity inherits from another entity more than once. This is redundant and

adds nothing to the model.

Manual correction Automatic correction

Delete redundant inheritances —

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Chapter 4. Working with Conceptual Data Models

Multiple inheritance

An entity has multiple inheritance. This is unusual but can be tolerated if

you deﬁned this check as a warning.

Manual correction Automatic correction

Make sure that the multiple in-

heritance is necessary in your

model

—

Parent of several inheritances

An entity is the parent of multiple inheritances. This is unusual but can be

tolerated if you deﬁned this check as a warning.

Manual correction Automatic correction

Verify if the multiple inheritances

could not be merged

—

Entity attribute check

During an entity attribute check, the following object controls are made.

Entity attribute name and code uniqueness

Attribute names and codes cannot be used more than once in the entity.

Manual correction Automatic correction

Modify the duplicate entity at-

tribute name/code

Modiﬁes the entity attribute name/code

of a selected object by appending a

number to its current name

Entity identiﬁer check

During an entity identiﬁer check, the following object controls are made.

Entity identiﬁer name and code uniqueness

Entity identiﬁer names and codes cannot be used more than once in the

namespace.

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Object parameters veriﬁed by Check model

Manual correction Automatic correction

Modify duplicate entity identiﬁer

names and codes

Modiﬁes the entity identiﬁer name/code

of a selected object by appending a

number to its current name

Existence of an attribute

At least one attribute must exist for an entity identiﬁer.

Manual correction Automatic correction

Add an attribute to the entity

identiﬁer or delete the identiﬁer

—

Identiﬁer inclusion

An identiﬁer cannot include another one.

Manual correction Automatic correction

Delete the identiﬁer that includes

an existing identiﬁer

—

Relationship check

During a relationship check, the following object controls are made.

Relationship name and code uniqueness

Relationship names and codes cannot be used more than once in the model.

Manual correction Automatic correction

Modify the duplicate relationship

name/code

Modiﬁes the relationship name/code of

a selected object by appending a number

to its current name

Reﬂexive dependency

A dependency means that one entity is deﬁned through a relationship with

another. A dependent relationship cannot therefore be reﬂexive.

Manual correction Automatic correction

Change or delete the reﬂexive

dependency

—

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Chapter 4. Working with Conceptual Data Models

Reﬂexive mandatory relationship

A reﬂexive mandatory relationship exists.

Manual correction Automatic correction

Deselect the Mandatory check

boxes for the relationship to be

non-mandatory

—

Bijective relationship between two entities

There is a bijective relationship between two entities when there is a

two-way one to one relationship between the entities. This is equivalent to a

merge of two entities.

Manual correction Automatic correction

Merge the entities or modify the

relationship

—

Name uniqueness constraint for many to many relationships and entities

A many-to-many relationship and an entity cannot have the same name or

code.

Manual correction Automatic correction

Change the name or code of the

many-to-many relationship or the

name or code of the entity. If

you do not, PDM generation will

rename the generated table

—

Consistency between dominant and dependent relationships

A dependent relationship between entities cannot also be a dominant

relationship.

Manual correction Automatic correction

Select the Dominant check box

on the other (correct) side of the

relationship

—

145

Object parameters veriﬁed by Check model

Association check

During an association check, the following object controls are made.

Association name and code uniqueness

Association names and codes cannot be used more than once in the

namespace.

Manual correction Automatic correction

Modify the duplicate association

name/code

Modiﬁes the association name/code of a

selected object by appending a number

to its current name

Association has at least two links

An association is isolated and therefore does not deﬁne a relationship

between entities.

Manual correction Automatic correction

Deﬁne at least two links between

the isolated association and one

or several entities

—

Association has two links with identiﬁer link

An identiﬁer link introduces a dependency between two entities. An

association with this type of link must be binary.

Manual correction Automatic correction

Delete the unnecessary links or

clear the Identiﬁer check box for

a link

—

Association has no more than one identiﬁer link

An identiﬁer link introduces a dependency between two entities. There can

only be one identiﬁer link between two entities otherwise a circular

dependency is created.

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Chapter 4. Working with Conceptual Data Models

Manual correction Automatic correction

Clear the Identiﬁer check box for

one of the links

—

Absence of properties with identiﬁer links

An association with an identiﬁer link cannot have any properties.

Manual correction Automatic correction

Move the association properties

into the dependent entity (the one

linked to the association with an

identiﬁer link)

—

Bijective association between two entities

There are bijective associations between two entities when a two-way one to

one association between the entities exist. This is equivalent to a merge of

two entities.

Manual correction Automatic correction

Merge the entities or modify the

cardinality links

—

Maximum cardinality links

An association with more than two links can only have links with a

maximum cardinality greater than one.

Manual correction Automatic correction

Change the maximum cardinality

of such links to be greater than 1

—

Reﬂexive identiﬁer links

An identiﬁer link introduces a dependency between two entities. An

association with this type of link cannot therefore be reﬂexive.

Manual correction Automatic correction

Change the relationship between

the entities or clear the Identiﬁer

check box for a link

—

147

Object parameters veriﬁed by Check model

Name unicity constraint between many-to-many associations and entities

A many-to-many association and an entity cannot have the same name or

code.

Manual correction Automatic correction

Change the name or code of the

many-to-many association or the

name or code of the entity. If

you do not, PDM generation will

rename the generated table

—

Inheritance check

During an inheritance check, the following object controls are made.

Inheritance name and code uniqueness

Inheritance names and codes cannot be used more than once in the model.

Manual correction Automatic correction

Modify the duplicate inheritance

name/code

Modiﬁes the inheritance name/code of a

selected object by appending a number

to its current name

Existence of inheritance link

An inheritance must have at least one inheritance link, from the inheritance

to the parent entity.

Manual correction Automatic correction

Deﬁne the inheritance link or

delete the inheritance

—

File object check

During a ﬁle object check, the following object controls are made.

Embedded ﬁle name uniqueness

You cannot have two embedded ﬁle objects with the same name in a model.

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Chapter 4. Working with Conceptual Data Models

Manual correction Automatic correction

Rename one of the embedded

ﬁle objects

Renames the ﬁle object by appending a

number to its name

Existence of external ﬁle location

External ﬁle objects must have a valid location path.

Manual correction Automatic correction

Deﬁne a valid path location —

Replication check

During a replication check, the following object controls are made.

Partial replication

A replica object is partially synchronized with its replicated object.

Manual correction Automatic correction

Modify the list of replicated

attributes from the replication

property sheet

Enforces the replication of desynchro-

nized attributes of the replica object in

the replication property sheet

Extended object check

During an extended object check, the following object controls are made.

Extended object name and code uniqueness

Extended object names and codes must be unique in the namespace.

Manual correction Automatic correction

Modify the duplicate extended ob-

ject name/code

Modiﬁes the extended object name or

code of a selected object by appending

a number to its current name or code

Extended link check

During an extended link check, the following object controls are made.

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Object parameters veriﬁed by Check model

Extended link name and code uniqueness

Extended link names and codes must be unique in the namespace.

Manual correction Automatic correction

Modify the duplicate extended link

name/code

Modiﬁes the extended link name or

code of a selected object by appending

a number to its current name or code

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Chapter 4. Working with Conceptual Data Models

Opening a PAM into a CDM

You can recover process model information into a conceptual model by

opening a PAM into a CDM.

You will then retrieve PAM objects into your CDM.

The open process translates PAM objects into CDM objects as follows:

Object in a PAM Imported object in a CDM

Business rule Business rule

Domain Domain

Data store Entity

Data item Data item

When opening a PAM, you are asked to choose between opening into a BPM

or opening into a CDM knowing that opening a PAM into a BPM allows you

to recover processes.

+For more information on opening a PAM into a BPM, see the

BPM

User’s Guide

vTo open a PAM into a CDM

1. Select File äOpen.

An open ﬁle dialog box appears.

2. Select or browse to the folder that contains the PAM ﬁle.

3. Select ProcessAnalyst Model (*.pam) ﬁle from the Files As Type

dropdown list box to display only PAM ﬁles.

The available PAM ﬁles are listed.

4. Select a ﬁle.

5. Click Open.

The Formats for ProcessAnalyst Model window appears.

151

Opening a PAM into a CDM

6. Select PowerDesigner Conceptual Data Model and click OK.

The Output window displays a message following the successful import

and the default diagram of the model appears. Each imported object type

can be viewed from its respective list.

152

CHAPTER 5

Generating from a Conceptual Data Model

About this chapter This chapter describes how you can generate a CDM, a PDM, and an OOM

from a Conceptual Data Model.

Contents Topic: page

Generation basics 154

Generating a Conceptual Data Model from a Conceptual Data

Model

155

Generating a Physical Data Model from a Conceptual Data Model 157

Generating an Object Oriented Model from a Conceptual Data

Model

171

153

Generation basics

You can generate a CDM, a PDM, or an OOM from a CDM.

+For more information on model to model or inter-model generation

common features, see the “Linking and Synchronizing Models in

PowerDesigner” chapter in the

General Features Guide

154

Chapter 5. Generating from a Conceptual Data Model

Generating a Conceptual Data Model from a

Conceptual Data Model

This section explains how to generate a Conceptual Data Model from a

Conceptual Data Model.

Why generate a CDM into a CDM?

You can generate a CDM into a CDM when you need to keep two models

synchronized during the design process.

This kind of generation allows you to create a copy of a given model and

deﬁne generation links between objects in the source CDM and their

equivalent in the generated CDM. When changes are made to the source

model, they can then be easily propagated to the generated models using the

Update Existing Model generation mode.

The generated model is the one that usually contains more information.

Generating and updating a CDM

To generate a CDM, you must choose between one of the following

methods:

♦Generate new Conceptual Data Model

♦Update existing Conceptual Data Model

You must indicate the following parameters when you generate a new CDM:

Parameter Description

Name File name for the resulting CDM

Code Reference code for the resulting CDM

Conﬁgure

Model Options

Lets you deﬁne the model options for the new CDM

+For more information, see the “Linking and Synchronizing Models in

PowerDesigner” chapter in the

General Features Guide

Deﬁning CDM generation options

You can set the following general generation options:

155

Generating a Conceptual Data Model from a Conceptual Data Model

Option Description

Check Model When selected, veriﬁes the model before generating the

CDM, and stops generation if an error is found

Save Genera-

tion Dependen-

cies

When selected, PowerDesigner keeps track of the identity

of the origin of each generated object. It is useful when

merging two CDM which have been generated from the

same CDM. Objects can be compared and recognized as

the same object, even if the object has been modiﬁed in

the merged CDM. If not selected, origin objects have no

link with generated objects

Enable transfor-

mations

This button is used to activate transformations during

generation.

When you click this button, the Pre-generation tab appears

if the source model contains transformations. You can

select the transformations to execute before generation.

The Extended Model Deﬁnitions tab also appears for you

to select extended model deﬁnition ﬁles to attach to the

generated model. These ﬁles may contain post-generation

transformations, in this case, the Post-Generation tab

appears to let you select the transformations you want

to be executed in the generated model. If the generation

is an update, and the generated model contains extended

model deﬁnitions with post-generation transformations,

the Post-generation tab automatically appears as soon as

you click the Enable Transformations button

Check model before generation

If you select the Check Model option, the procedure to generate a CDM

starts by checking the validity of the CDM . A CDM results when no errors

are found. You can set check options by selecting Tools äCheck Model.

156

Chapter 5. Generating from a Conceptual Data Model

Generating a Physical Data Model from a

Conceptual Data Model

This section explains how to generate a Physical Data Model from a

Conceptual Data Model.

Generating PDM objects

When you generate a physical data model (PDM) from a CDM,

PowerDesigner converts CDM objects and data types to PDM objects and

data types supported by the current DBMS.

Converting CDM to PDM objects

PDM generation converts conceptual objects into physical objects as

follows:

CDM objects Generated object in a PDM

Entity Table

Entity attribute Table column

Primary identiﬁer Primary or foreign key depending on independent or

dependent relationship

Identiﬁer Alternate key

Relationship Reference

Changing the name of a column automatically

Two columns in the same table cannot have the same name. If column

names conﬂict due to foreign key migration, PowerDesigner automatically

renames the migrated columns. The new name is composed of the ﬁrst

three letters of the original entity name followed by the code of the attribute.

Generating keys from identiﬁers

Primary identiﬁers generate primary and foreign keys in the PDM.

Identiﬁers that are not primary identiﬁers generate alternate keys.

The type of key that is generated in the PDM depends on the cardinality and

type of dependency deﬁned for a relationship in the CDM.

Aprimary key is a column or columns whose values uniquely identify a

row in a table.

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Generating a Physical Data Model from a Conceptual Data Model

Aforeign key is a column or columns that depend on and migrate from a

primary key column in another table.

An alternate key is a column or columns whose values uniquely identify a

row in a table, and is not a primary key.

Independent

one-to-many

relationships

In independent one-to-many relationships, the primary identiﬁer of the entity

on the one side of the relationship becomes a:

♦Primary key in the table generated by the entity on the one side of the

relationship

♦Foreign key in the table generated by the entity on the many side of the

relationship

The CDM below shows an independent relationship. Each division contains

one or more employees:

The CDM above generates two tables:

Table Primary key Foreign key

Division Division number —

Employee Employee number Division number

The following PDM results from generation:

Dependent one-to-many

relationships

In dependent relationships, the primary identiﬁer of the nondependent entity

becomes a primary/foreign key in the table generated by the dependent

entity.

The migrated column is integrated into the primary key if it already exists.

The CDM below shows a dependent relationship. Each task must have a

project number.

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Chapter 5. Generating from a Conceptual Data Model

The CDM above generates two tables:

Table Primary key Foreign key

Project Project number —

Task Project number/Task num-

ber

Project number

The following PDM results from generation.

Independent

many-to-many

relationships

In independent many-to-many relationships, the primary identiﬁers of both

entities migrate to a join table as primary/foreign keys. The CDM below

shows an independent relationship. Each employee can be a member of one

or more teams, and each team can have one or more employees as members.

Table Primary key Foreign key

Team Team number —

Employee Employee number —

Member Team number/Employee num-

ber

Team number/Employee num-

ber

The following PDM results from generation.

Independent one-to-one

relationships

In independent one-to-one relationships, the primary identiﬁer of one entity

migrates to the other generated table as a foreign key.

159

Generating a Physical Data Model from a Conceptual Data Model

Generating tables from entities with inheritance links

Two properties inﬂuence the generation of tables from entities with

inheritance links.

Object Property When selected generates

Entity Generate table Table for the entity (parent or child)

Inheritance Generation mode Parent and/or children as indicated

Converting CDM to PDM data types

PowerDesigner supports both conceptual and physical data types. Data types

that you select in the CDM are not always supported by the current DBMS.

In this case, the data type is converted to a data type supported by the current

DBMS when you generate the PDM.

Accessing the DBMS to deﬁne data type conversions

Each DBMS contains rules for data type conversion.

The correspondence between the PowerDesigner data type and the physical

data type for the current DBMS is listed under the Data Type node, under the

Script node in the DBMS tree view.

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Chapter 5. Generating from a Conceptual Data Model

The Physical Model column lists the data types for the current DBMS and

the Internal column lists the PowerDesigner equivalent. You can modify the

deﬁnition of an existing physical data type by making modiﬁcations directly

to either of the two columns.

Modifying the DBMS

You should only modify a copy of the DBMS shipped with PowerDesigner.

Once a modiﬁcation has been committed in the DBMS you cannot return

to the default value for the data type.

+For more information on modifying a DBMS, see chapter DBMS Basics

in the Physical Data Model User’s Guide.

vTo access a DBMS

1. Select Tools äResources äDBMS to display the List of DBMS.

2. Select a DBMS from the list.

Click the Properties tool.

Double-click a DBMS name in the list.

The DBMS property sheet appears.

3. From the General page, expand the Script node, then expand the Data

Type node.

4. Select the item PhysDataType.

The values for the DBMS data types and the corresponding

PowerDesigner data types appear in the Value pane to the left of the tree

view.

5. Click OK.

Converting conceptual data types

The following table lists the conceptual data types to which the DBMS

assigns conversions:

Numeric data types

Conceptual

data type

Code in

DBMS

What it stores Conversion example

for SQL Anywhere

Integer I 32-bit integer integer

Short Integer SI 16-bit integer smallint

161

Generating a Physical Data Model from a Conceptual Data Model

Conceptual

data type

Code in

DBMS

What it stores Conversion example

for SQL Anywhere

Long Integer LI 32-bit integer integer

Byte BT 256 values smallint

Number N Numbers with a ﬁxed

decimal point

numeric

Decimal DC Numbers with a ﬁxed

decimal point

decimal

Float F 32-bit ﬂoating point

decimal numbers

ﬂoat

Short Float SF Less than 32-bit ﬂoat-

ing point decimal num-

ber

real

Long Float LF 64-bit ﬂoating point

decimal numbers

double

Money MN Numbers with a ﬁxed

decimal point

numeric

Serial NO Automatically incre-

mented numbers

numeric

Boolean BL Two opposing values

(true/false; yes/no;

1/0)

numeric(1)

Character data types

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Chapter 5. Generating from a Conceptual Data Model

Conceptual

data type

DBMS What it stores Conversion example for

SQL Anywhere

Characters A Character strings char

Variable

Characters

VA Character strings varchar

Long Charac-

ters

LA Character strings varchar

Long Var

Characters

LVA Character strings long varchar

Text TXT Character strings long varchar

Multibyte MB Multibyte charac-

ter strings

char

Variable

Multibyte

VMB Multibyte charac-

ter strings

varchar

Time data types

Conceptual

data type

DBMS What it stores Conversion example

for SQL Anywhere

Date D Day, month, year date

Time T Hour, minute, and

second

time

Date & Time DT Date and time timestamp

Timestamp TS System date and time timestamp

Other data types

163

Generating a Physical Data Model from a Conceptual Data Model

Conceptual

data type

DBMS What it stores Conversion example

for SQL Anywhere

Binary BIN Binary strings binary

Long Binary LBIN Binary strings long binary

Image PIC Images long binary

Bitmap BMP Images in bitmap

format (BMP)

long binary

OLE OLE OLE links long binary

Other * User-deﬁned data

type

char(10)

Undeﬁned

<UNDEF>

Not yet deﬁned data

type

<undeﬁned>

Generating and updating a PDM

To generate a PDM, you must choose between one of the following methods:

♦Generate new Physical Data Model

♦Update existing Physical data Model

You must indicate the following parameters when you generate a new PDM:

Parameter Description

DBMS Database Management System deﬁnition (DBMS) for the

resulting PDM

Share The resulting PDM uses a shared DBMS deﬁnition ﬁle

stored in the DBMS library

Copy The resulting PDM uses a copy of the DBMS deﬁnition

ﬁle stored in the model

Name File name for the resulting PDM

Code Reference code for the resulting PDM

Conﬁgure

Model Options

Lets you deﬁne the model options for the new PDM

+For more information, see the “Linking and Synchronizing Models in

PowerDesigner” chapter in the

General Features Guide

164

Chapter 5. Generating from a Conceptual Data Model

Conﬁguring the generated PDM options

When you conﬁgure the options of a PDM to generate, you may deﬁne

options diverging from the CDM options.

To avoid conﬂicts, PowerDesigner applies the following rule for default

values of PDM options: an option deﬁned for the generated PDM should

respect the equivalent option of the CDM.

Equivalent options are model options found in both models. The Enforce

non-divergence option exists in both CDM and PDM.

CDM option PDM option Result in generated PDM

4En-

force non-

divergence

— Enforce non-divergence in model ac-

cording to CDM options. Columns

attached to the domain cannot have

divergent deﬁnitions

—4Enforce non-

divergence

Enforce non-divergence in model ac-

cording to PDM options deﬁned using

the Conﬁgure Model Options feature

References unique code Unique Code for references is not selected by default in the PDM options.

However, if you select Unique Code for references in the PDM options,

relationships are renamed during the generation of a CDM to a PDM.

Options with no equivalent, like Use Data Type Full Name in the CDM

without any corresponding option in a PDM, are generated using default

values found in the registry.

Deﬁning PDM generation options

You can set the following general generation options from the Detail page:

165

Generating a Physical Data Model from a Conceptual Data Model

Option Description

Check Model When selected, checks the model before generating the

PDM, and stops generation if an error is found

Save Genera-

tion Dependen-

cies

When selected, PowerDesigner keeps track of the identity

of the origin of each generated object. This is useful when

merging two PDM which have been generated from the

same CDM. Objects can be compared and recognized as

the same object, even if the object has been modiﬁed in

the target PDM. If not selected, origin objects have no link

with generated objects

Convert Names

into Codes

When selected, object codes are generated from names

using the corresponding conversion script. This is useful

when generating models with very different naming con-

ventions . For example a Java class attribute code may be

“customerName” whereas a PDM table column code may

be “CUSTOMER_NAME”. With this option selected,

both objects will have their codes generated from their

names. If you do not select this option, generated object

codes will be copied from original object codes

Rebuild Trig-

gers

When selected, allows to build triggers with preservation

option, after the PDM generation. Rebuild takes place

after merge if you are updating an existing PDM

Enable transfor-

mations

This button is used to activate transformations during

generation.

When you click this button, the Pre-generation tab appears

if the source model contains transformations. You can

select the transformations to execute before generation.

The Extended Model Deﬁnitions tab also appears for you

to select extended model deﬁnition ﬁles to attach to the

generated model. These ﬁles may contain post-generation

transformations, in this case, the Post-Generation tab

appears to let you select the transformations you want

to be executed in the generated model. If the generation

is an update, and the generated model contains extended

model deﬁnitions with post-generation transformations,

the Post-generation tab automatically appears as soon as

you click the Enable Transformations button

+For more information conversion scripts, see section Using a conversion

script in chapter Managing models in the

General Features Guide

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Chapter 5. Generating from a Conceptual Data Model

Check model before generation

If you select the Check Model option, the procedure to generate a PDM

starts by checking the validity of the CDM . A PDM results when no errors

are found. You can set check options by selecting Tools äCheck Model.

Table parameters The following parameter deﬁnes the naming convention for tables:

Parameter Description

Table Preﬁx Preﬁx for the names of tables generated from entities in the

CDM

Reference parameters The following parameters deﬁne default referential integrity constraints:

Parameter Description

Update Rule Default update constraint for referential integrity

Delete Rule Default delete constraint for referential integrity

Foreign key name By default, the name of the migrated foreign keys generated in a PDM is

identical to the name of the primary key. In case of column name conﬂict,

the ﬁrst 3 letters of the name of the parent table are added before the name of

the migrated column.

You can modify this default behavior and use templates for naming the

migrated foreign keys. In the Reference groupbox, you can select one of the

predeﬁned templates in the FK Column Name Template dropdown listbox.

These templates are saved in the registry, you can modify them, but their

default value is preserved.

You can also create your own foreign key naming templates by typing a

template directly in the FK Column Name Template box using the following

variables:

167

Generating a Physical Data Model from a Conceptual Data Model

Variable Value

%REFR% Name / Code of the reference

%PARENT% Name / Code of the parent table

%COLUMN% Name / Code of the parent column

%KEY% Name / Code of the key constraint attached to the

reference

%CONSTNAME% Name of the key constraint attached to the reference

(same as %KEY%)

%PROLE% Role of the entity that generated the parent table, this

variable proceeds from the conceptual environment.

If no role is deﬁned on the relationship or association,

%PROLE% takes the content of %PARENT% to

avoid generating a column with no name

You can use the default PowerDesigner formatting variables in the template

as explained in section List of PowerDesigner formatting variables in

chapter Variables in PowerDesigner in the

PDM User’s Guide

You can also use square brackets [ ] for evaluating optional variables as

explained in “Optional strings and variables” in the “DBMS Reference

Guide” chapter in the

Advanced User Documentation

Customized naming templates reappear in the generation dialog box the next

time you open it, but are not saved in the registry thus not added to the

dropdown list of predeﬁned templates.

For example, if you deﬁne the template %PROLE%, the name of the foreign

key will be made of the role beside the entity that generated the parent table

containing the primary key. If the parent table contains multiple keys, the

foreign key names will be automatically renamed.

Other example:

[%PROLE%=%PARENT%?%.3:PARENT%_%COLUMN%:%PROLE%]

This checks the %PROLE% value; if it is equal to the parent name (which is

the replacement value) then the template “%.3:PARENT%_%COLUMN%”

will be used, otherwise template “%PROLE%” will be used because the user

has entered a parent role for the relationship.

In the Reference groupbox, you can select the Always Use Template radio

button to always use the default or customized template for naming FK

168

Chapter 5. Generating from a Conceptual Data Model

columns, even if there is no conﬂict with an existing column.

Index parameters The following parameters deﬁne naming conventions for indexes:

Parameter Description

PK index names Naming convention for primary keys, by default

%TABLE%_PK

Key index names Naming convention for alternate keys, by default

%TABLE%_AK

FK index names Naming convention for foreign keys, by default

%REFR%_FK

FK threshold Minimum number of estimated occurrences of an entity

necessary to create an index on a foreign key

If you enter a value for the index threshold, indexes on foreign keys are only

generated if the number of estimated occurrences is greater than the

threshold. The estimated number of occurrences is an entity property that

you can include in the entity deﬁnition.

If the entity has no speciﬁed number of occurrences, the foreign key indexes

are generated by default.

PK index name variables You can use the following variables in the PK index names and Key Index

Names ﬁelds:

Variable Value

%TABLE% Generated code of the table. This is the table code that is

generated in the database. It may or may not be truncated

if the code contains characters not supported by the

DBMS

%TNAME% Table name

%TCODE% Table code

%TLABL% Table comment

FK index name variables You can use the following variables in the FK index name ﬁeld. The

generated code of a variable is the code deﬁned in the object property sheet,

but which may or may not be truncated when generated if the code contains

characters not supported by the DBMS

Variable Value

%REFR% Generated code of the reference

169

Generating a Physical Data Model from a Conceptual Data Model

Variable Value

%REFNAME% Reference name

%REFRCODE% Reference code

%PARENT% Generated code of the parent table

%PNAME% Parent table name

%PCODE% Parent table code

%CHILD% Generated code of the child

%CNAME% Child table name

%CCODE% Child table code

%PQUALI-

FIER%

Parent table qualiﬁer

%CQUALI-

FIER%

Child table qualiﬁer

Preserving a modiﬁed primary key

If you modify a primary key in a PDM, then regenerate the PDM from a

CDM, the modiﬁed primary key is not preserved. If you want to preserve a

modiﬁed primary key, you need to modify the identiﬁer in the CDM before

regeneration.

170

Chapter 5. Generating from a Conceptual Data Model

Generating an Object Oriented Model from a

Conceptual Data Model

This section explains how to generate an Object Oriented Model from a

Conceptual Data Model.

Generating OOM Objects

When you generate an Object Oriented Model (OOM) from a CDM,

PowerDesigner converts CDM objects into speciﬁed object language objects

as follows:

CDM Objects Generated object in an OOM

Entity Class

Attribute Attribute

Association Relationship or association

Binary association with at-

tributes

Association class

Inheritance Generalization

Persistent entities All entities are generated as persistent classes with the “Generate table”

persistence mode.

When the Generate check box of an entity is not selected, the generated class

has the “Migrate columns” persistence mode.

OOM naming conventions

If the code of the generated OOM objects does not correspond to the target

language naming conventions, you can deﬁne a code naming convention

script to convert object names into codes. For more information on

conversion scripts, see section .convert_name & .convert_code macros in

chapter Managing Models in the

General Features Guide.

Converting CDM to OOM data types

PowerDesigner supports both conceptual and object language data types.

The following table lists the conceptual data types to which the object

language deﬁnition assigns conversions:

171

Generating an Object Oriented Model from a Conceptual Data Model

Conceptual

data type

Code in

CDM

What it stores Conversion exam-

ple with Java

Characters A Character strings Char

Boolean BL Two opposing values

(true/false; yes/no; 1/0)

Boolean

Byte BT 256 values Byte

Short Integer SI 16-bit integer Short

Long Integer LI 32 bit integer Long integer

Integer I 32 bit integer Integer

Float F 32 ﬂoating decimal num-

bers

Float

Number N Numbers with a ﬁxed deci-

mal point

Double

Text TXT Character strings *

Generating and updating an OOM

To generate an OOM, you must choose between one of the following

methods:

♦Generate new Object-Oriented Model

♦Update existing Object-Oriented Model

You must indicate the following parameters when you generate a new OOM:

172

Chapter 5. Generating from a Conceptual Data Model

Parameter Description

Object Language Target object language

Share Object language for the resulting OOM uses a shared

Object language deﬁnition ﬁle stored in the Object

language library

Copy Object language for the resulting OOM uses a copy of

the Object language deﬁnition ﬁle stored in the Object

language library

Name File name for the resulting OOM

Code Reference code for the resulting OOM

Conﬁgure Model

Options

Lets you deﬁne the model options for the new OOM,

you can select the naming conventions corresponding

to the target language for example

+For more information, see the “Linking and Synchronizing Models in

PowerDesigner” chapter in the

General Features Guide

Conﬁguring the generated OOM options

When you conﬁgure the options of an OOM to generate, you may deﬁne

options diverging from the CDM options.

To avoid conﬂicts, PowerDesigner applies the following rule for default

values of OOM options: an option deﬁned for the generated OOM should

respect the equivalent option of the CDM.

Equivalent options are model options found in both models. The Enforce

non-divergence option exists in both CDM and OOM.

CDM option OOM option Result in generated OOM

4En-

force non-

divergence

— Enforce non-divergence in model ac-

cording to CDM options

—4Enforce non-

divergence

Enforce non-divergence in model ac-

cording to OOM options deﬁned using

the Conﬁgure Model Options feature

Options with no equivalent, like Use Data Type Full Name in the CDM

without any corresponding option in an OOM, are generated using default

values found in the registry.

173

Generating an Object Oriented Model from a Conceptual Data Model

Deﬁning OOM generation options

You can set the following general generation options from the Detail page:

Option Description

Check Model When selected, checks the model before generating the

OOM, and stops generation if an error is found

Save Genera-

tion Dependen-

cies

When selected, PowerDesigner keeps track of the identity

of the origin of each generated object. It is useful when

merging two OOM which have been generated from the

same CDM. Objects can be compared and recognized as

the same object, even if the object has been modiﬁed in the

target OOM. If not selected, origin objects have no link

with generated objects

Convert Names

into Codes

When selected, object codes are generated from names

using the corresponding conversion script. This is use-

ful when generating models with very different naming

conventions since conversion macros are used to modify

codes. For example a Java class attribute code may be

“customerName” whereas a PDM table column may be

“CUSTOMER_NAME”. With this option selected, both

objects will have their codes generated from their names.

If you do not select this option, generated object codes

will be copied from original object codes

Enable transfor-

mations

This button is used to activate transformations during

generation.

When you click this button, the Pre-generation tab appears

if the source model contains transformations. You can

select the transformations to execute before generation.

The Extended Model Deﬁnitions tab also appears for you

to select extended model deﬁnition ﬁles to attach to the

generated model. These ﬁles may contain post-generation

transformations, in this case, the Post-Generation tab

appears to let you select the transformations you want

to be executed in the generated model. If the generation

is an update, and the generated model contains extended

model deﬁnitions with post-generation transformations,

the Post-generation tab automatically appears as soon as

you click the Enable Transformations button

Class Preﬁx Preﬁx for a class. It can help identify a class in a model

174

Chapter 5. Generating from a Conceptual Data Model

+For more information conversion scripts, see section Using a conversion

script in chapter Managing models in the

General Features Guide

Check model before generation

If you select the Check Model option, the procedure to generate an OOM

starts by checking the validity of the CDM . An OOM results when no

errors are found. You can set check options by selecting Tools äCheck

Model.

175

CHAPTER 6

CDM Glossary

association In the Merise modeling methodology an association is a connection between

entities

business rule Written statement specifying what the information system must do or how it

must be structured to support business needs

column Data structure that contains an individual data item within a row in a PDM

Conceptual Data Model

(CDM)

Entity-relationship diagram that models the information system without

considering the details of physical implementation

constraint Named check that enforces data requirements, default values, or referential

integrity on an entity or a entity attribute

data item Elementary piece of information

domain Set of values for which a data item is valid

entity Person, place, thing, or concept that has characteristics of interest to the

enterprise and about which you want to store information

entity attribute Elementary piece of information attached to an entity

foreign key Column or columns in a PDM whose values depend on and migrate from a

primary key, or an alternate key, in another table

Identiﬁer Entity attribute, or a combination of entity attributes, whose values uniquely

identify each occurrence of the entity

Inheritance Special relationship that deﬁnes an entity as a special case of a more general

entity

Object-Oriented Model

(OOM)

Structure that is the logical design view of a software system. An OOM is a

conceptual model of a software system

Physical Data Model

(PDM)

Table-reference diagram that models the information system including the

details of physical implementation

primary key Column or columns whose values uniquely identify a row in a table in PDM

property sheet Window that displays the properties of an object

reference Link between a parent table and a child table in a PDM. A reference can link

177

tables by shared keys or by speciﬁed columns

referential integrity Rules governing data consistency, speciﬁcally the relationships among

primary keys and foreign keys of different tables in a PDM

relationship Named connection or association between entities

stereotype Sub-classiﬁcation used to extend the semantics of an object without

changing its structure; it can be predeﬁned or user-deﬁned

table Collection of rows (records) in a PDM that have associated columns (ﬁelds)

178

Index

All Objects option 5

association (CDM) 3

cardinality 101

change to entity 104

check model 146

create from Browser 97

create from diagram 97

create from list 97

deﬁne 95, 104

dependent 103

display preferences 108

entity 104

entity attribute 104

properties 96

reﬂexive 100

validity check 136

association attribute (CDM)

create 105

create from list 107

list 105

validity check 136

association link

cardinality 101

create from diagram 98

create from list 98, 99

deﬁne 96

display preferences 109

drag 98

properties 96

symbol 98

attribute (CDM) 3

association 105

enforce coherence 10

bibliography vii

binary data type 46, 163

bitmap data type 46, 163

boolean data type 44, 161

business rule (CDM) 22, 23

apply 27, 126

check model 136

create 24

deﬁnition 23

domain (CDM) 50

expression 26, 126

fact 23

formula 23

properties 23

requirement 23

type 23

validation 23

validation rule 126

byte data type 44, 161

cardinality

association (CDM) 101

change format 101

change from the registry 101

deﬁne 80

deﬁne for an association link 101

many to many 80

many to one 80

one to many 80

one to one 80

relationship 80, 91

CDM

check 130, 131, 135

check options 130

check results 134

close 17

correct 134, 135

create 14

data type 161

deﬁne 2, 13

detach from workspace 17

domain 40

enable transformations 155

enforce domain 4

Entity Relationship Diagram 2

ERD 2

179

Index

error 36, 79, 130, 131, 134, 135

extended dependency 12

extended model deﬁnition 11

generate 154, 155

generation option 155

generation parameter 155

logical model 2

modify properties 13

object 3, 157, 171

open 16

open PAM 151

option 11, 35, 79

package 18

role 2

save 17

validate 130

warning 130, 131, 134, 135

CDM environment 4

Change to Entity Wizard 89

check model

association (CDM) check 146

automatic correction 130

business rule (CDM) 136

CDM 130, 131, 135

correct 134, 135

data item check 139

domain check 137

entity attribute check 143

entity check 141

entity identiﬁer check 143

error severity 130

extended link 149

extended object 149

ﬁle object 148

global model 131

inheritance check 148

model 136

object parameters 136

option 130, 131, 136

package (CDM) check 136

relationship 144

replication (CDM) check 149

set error severity 130

warning 130

check parameter

column 123, 126

data type 37, 65

deﬁne 123

domain (CDM) 50, 123, 126

properties 123

standard 123

type 123

validation rule 22, 123, 126

client

business rule (CDM) 26

expression 26, 126

close CDM 17

code

data item 35

option 79

package (CDM) 19

relationship 79

unique 35, 79

code naming convention 171

column

check parameter 123, 126

generate 157

rename 157

validation rule 126

variable 126

composite view 18

conﬁgure

OOM options 173

PDM options 165

convert

CDM to OOM objects 171

CDM to PDM objects 157, 160

data type 160, 171

correct

automatic 130

CDM 134, 135

check 134, 135

error 130

manual 135

data item 3

add as entity attribute 34, 60

associate domain 36

association 105

check model 139

code 35

copy 54

create from Browser 31

180

Index

create from list 31

data type 37, 66

deﬁne 30

delete 33, 67

domain (CDM) 36

duplicate 34

error 36

non-divergence 50

option 34, 54

properties 30

reuse 4, 35, 60, 67

sort list 39

unique 4

unique code 35

use as entity attribute 60

validity check 136

data type 42, 44

binary 46, 163

bitmap 46, 163

boolean 44, 161

byte 44, 161

character 45

conceptual 161

conversion in DBMS 160

convert to OOM 171

convert to PDM 160

data item 37, 66

date 46, 163

decimal 44, 161

default 4

deﬁne 160

domain (CDM) 42, 43, 48, 50

entity attribute 64

ﬂoat 44, 161

image 46, 163

integer 44, 161

length 42, 44

map to OOM 171

map to PDM 160

money 44, 161

number 44, 161

OLE 46, 163

precision 42, 44

select 37, 64

select from list 42

select from property sheet 42, 43

select from the list 43

serial 44, 161

show full name 4

time 46, 163

undeﬁned 37, 42, 43, 46, 48, 66, 163

Data Type Full Name option 10

date data type 46, 163

DBMS data type conversion 160

decimal data type 44, 161

Default Data Type option 11

delete data item 67

dependent association (CDM) 103

detach CDM from workspace 17

display preference

association (CDM) 108

association link 109

entity 56

inheritance 122

package (CDM) 20

relationship 93

diverge from domain 10

domain (CDM) 3

business rule 50

CDM 40

check model 137

check parameter 50, 123, 126

create from Browser 41

create from list 41

data item 36

data type 42–44, 48, 50

deﬁne 40

diverge from 10

enforce 50

enforce coherence 4, 10

entity attribute 50, 63

length 42, 44

modify properties 48

non-divergence 50

precision 42, 44

properties 40

use 50

validation rule 126

validity check 136

variable 126

Domain and Attribute option 10

dominant relationship 87

duplicate data item 34

181

Index

E/R + Merise 6

enforce domain (CDM) 50

entity 3

add to inheritance 113

association 104

associative 89

change from association 104

change from relationship 89

check model 141

copy 54

create from Browser 52

create from diagram 52

create from list 52

deﬁne 52

delete 67

display preferences 56

entity attribute 54, 67

generate table 160

identiﬁer 54, 67, 69

inheritance 110, 160

modify from list 54

modify from property sheet 54

properties 52, 54

validity check 136

wizard 89

entity attribute

add 34, 60

add to identiﬁer 71

associate domain 63

association 104

attach to domain 63

check model 143

copy 54

create 62

create from data item 60

create from list 60

data item 34, 60

data type 64

deﬁne 59

delete 67

domain (CDM) 50, 63

entity 67

identiﬁer 54, 67, 69

inheritance 118

list 62, 67

mandatory 66

optional 66

properties 59, 118

relationship 89

reuse 60, 67

specifying entity attribute 118, 120

validity check 136

entity identiﬁer check 143

entity/relationship 6

notation 4

ERD

CDM 2

Entity Relationship Diagram 2

Relationship tool 3

error

check model 130

severity 130

error message

CDM 130, 131, 134

data item 36

display 134

relationship 79

unique code 36, 79

expression

business rule (CDM) 26, 126

client 26, 126

server 26, 126

extended dependency (CDM) 12

extended link

check 149

code uniqueness 150

name uniqueness 150

extended model deﬁnition (CDM) 11

extended object

check 149

code uniqueness 149

name uniqueness 149

ﬁle object

check 148

external 149

name uniqueness 148

ﬂoat data type 44, 161

foreign key 167

generate 169

generate from identiﬁer 157

index 169

182

Index

name 169

name template for generation 167

general option 35, 79

generate

CDM 154, 155

CDM from CDM 155

column 157

conﬁgure OOM options 173

conﬁgure PDM options 165

foreign key 157, 169

foreign key name 167

index parameter 169

inheritance 160

new CDM 155

new model 154

new OOM 172

new PDM 164

OOM 172–174

OOM from CDM 171

OOM object 171

OOM object conversion 171

PDM 164, 165

PDM from CDM 157

PDM object 157

PDM object conversion 160

PDM option 165

primary key 157, 169

reference parameter 167

table 160

table parameter 167

update existing CDM 155

update model 154

validation rule 126

global model

CDM 131

check 131

IDEF1X 6

identiﬁer 69

child 117

copy 54

deﬁne 69

delete 67

designate 69

entity attribute 54, 67, 71

generate key 157

modify from list 73

modify from property sheet 73

parent 117

primary identiﬁer 72

image data type 46, 163

Include Sub-Objects tool 131

index

foreign key 169

generate 169

primary key 169

inheritance 3

add child entity 113

check model 148

child 116

complete 110

create 112

deﬁne 110, 117, 120

display preferences 122

entity attribute 118

generate 116

generation mode 116, 117

link 112

mutually exclusive 115

parent 116

primary key 117

properties 110, 116

specifying entity attribute 120

validity check 136

integer data type 44, 161

list

arrange 67

order 67

location for ﬁle object 149

logical model 2

manual correction 135

map

CDM to OOM 171

CDM to PDM 160

Merise 6

association (CDM) 95

notation 4

183

Index

model

object selection 131

OOM options 173

open 151

option 35, 79

PDM options 165

sub-object 131

model option

all objects 5

data item 9

data type full name 10

default data type 11

domain and attribute 10

notation 6

relationship 10

money data type 44, 161

name

ﬁle object 148

foreign key 169

package (CDM) 19

primary key 169

name uniqueness

extended link 150

extended object 149

Name/Code Case Sensitive option 4

namespace for package (CDM) 19

non-divergence

data item 50

domain (CDM) 50

notation

Entity/Relationship 4

Merise 4

Notation option 6

number data type 44, 161

object

business rule (CDM) 27

CDM 3

object selection

check 131

model 131

package 131

OLE data type 46, 163

OOM

code naming convention 171

enable transformations 174

generate object 171

generation option 174

generation parameter 172

map CDM object 171

object 171

option

CDM 35, 79

check 130, 131, 136

code 79

conﬁgure for generated OOM 173

conﬁgure for generated PDM 165

data item 34, 54

general 35, 79

model 35, 79

relationship 79

package (CDM)

CDM 18

check model 136

code 19

comment 19

composite view 18

create 19

deﬁne 18

display preferences 20

name 19

namespace 19

object selection 131

properties 19

shortcut code uniqueness 137

shortcut generated as child table 137

validity check 136

PAM opened into CDM 151

PDM

enable transformations 165

generate 164

generate object 157

generation option 165

generation parameter 164

map CDM object 160

object 157

update 164

precision 42, 44

primary identiﬁer 72

184

Index

primary key

child 117

generate 169

generate from identiﬁer 157

index 169

inheritance 117

name 169

reference

foreign key name 167

generate 167

reﬂexive association (CDM) 100

relationship 3

associative entity 89

bend 94

cardinality 80, 91

change to entity 89

check model 144

code 79

create 78

create from Browser 76

create from diagram 76

create from list 76

deﬁne 75, 85, 87, 89

dependent 85

display 94

display preferences 93

dominant 87

drag 94

entity attribute 89

ERD 3

error 79

example 91

mandatory 83

modify 94

modify from list 79

modify from property sheet 79

option 79

optional 83

properties 75, 79

reﬂexive 78

sort list 90

termination point 81, 83

unique code 4, 79

Relationship option 10

replication (CDM) check 149

rule 23

save CDM 17

serial data type 44, 161

server

business rule (CDM) 26

expression 26, 126

shortcut code uniqueness in package 137

shortcut generated as child table 137

specifying attribute

create 120, 121

list 120, 121

specifying entity attribute 118, 120

standard data type list 44

sub-object check 131

Sybase SQL Anywhere data types 161

table generation 160, 167

time data type 46, 163

type of business rule (CDM) 23

typographic conventions vi

undeﬁned data type 37, 42, 43, 48, 66

validation rule 123

apply 126

business rule (CDM) 126

check parameter 126

column 126

domain (CDM) 126

generate 126

variable

column 126

domain (CDM) 126

warning in CDM check 130, 131, 134, 135

warning message of last check 134

185

CDM User Guide

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