CA ERwin
®
Data Modeler
Methods Guide
r7.3
This documentation and any related computer software help programs (hereinafter referred to as the
“Documentation”) is for the end user’s informational purposes only and is subject to change or withdrawal by CA at
any time.
This Documentation may not be copied, transferred, reproduced, disclosed, modified or duplicated, in whole or in
part, without the prior written consent of CA. This Documentation is confidential and proprietary information of CA
and protected by the copyright laws of the United States and international treaties.
Notwithstanding the foregoing, licensed users may print a reasonable number of copies of the Documentation for
their own internal use, and may make one copy of the related software as reasonably required for back-up and
disaster recovery purposes, provided that all CA copyright notices and legends are affixed to each reproduced copy.
Only authorized employees, consultants, or agents of the user who are bound by the provisions of the license for
the Product are permitted to have access to such copies.
The right to print copies of the Documentation and to make a copy of the related software is limited to the period
during which the applicable license for the Product remains in full force and effect. Should the license terminate for
any reason, it shall be the user’s responsibility to certify in writing to CA that all copies and partial copies of the
Documentation have been returned to CA or destroyed.
EXCEPT AS OTHERWISE STATED IN THE APPLICABLE LICENSE AGREEMENT, TO THE EXTENT PERMITTED BY
APPLICABLE LAW, CA PROVIDES THIS DOCUMENTATION “AS IS” WITHOUT WARRANTY OF ANY KIND, INCLUDING
WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
OR NONINFRINGEMENT. IN NO EVENT WILL CA BE LIABLE TO THE END USER OR ANY THIRD PARTY FOR ANY
LOSS OR DAMAGE, DIRECT OR INDIRECT, FROM THE USE OF THIS DOCUMENTATION, INCLUDING WITHOUT
LIMITATION, LOST PROFITS, BUSINESS INTERRUPTION, GOODWILL, OR LOST DATA, EVEN IF CA IS EXPRESSLY
ADVISED OF SUCH LOSS OR DAMAGE.
The use of any product referenced in the Documentation is governed by the end user’s applicable license
agreement.
The manufacturer of this Documentation is CA.
Provided with “Restricted Rights.” Use, duplication or disclosure by the United States Government is subject to the
restrictions set forth in FAR Sections 12.212, 52.227-14, and 52.227-19(c)(1) - (2) and DFARS Section 252.227-
7014(b)(3), as applicable, or their successors.
All trademarks, trade names, service marks, and logos referenced herein belong to their respective companies.
Copyright © 2008 CA. All rights reserved.
CA Product References
This document references the following CA products:
■
CA
®
ERwin
®
Data Modeler (CA ERwin DM)
■
CA
®
Model Manager (CA ERwin MM)
■
CA
®
Process Modeler (CA ERwin PM)
Contact CA
Contact Technical Support
For your convenience, CA provides one site where you can access the
information you need for your Home Office, Small Business, and Enterprise CA
products. At http://ca.com/support
, you can access:
■
Online and telephone contact information for technical assistance and
customer services
■
Information about user communities and forums
■
Product and documentation downloads
■
CA Support policies and guidelines
■
Other helpful resources appropriate for your product
Provide Feedback
If you have comments or questions about CA product documentation, you can
send a message to techpubs@ca.com.
If you would like to provide feedback about CA product documentation, please
complete our short customer survey, which is also available on the CA support
website, found at http://ca.com/support
.
Contents
Chapter 1: Introduction 9
Data Modeling Concepts........................................................................ 9
Benefits of Data Modeling ..................................................................... 10
Methods ..................................................................................... 10
Typographical Conventions .................................................................... 10
Chapter 2: Information Systems, Databases, and Models 13
Introduction.................................................................................. 13
Data Modeling ............................................................................ 14
Process Modeling ......................................................................... 15
Data Modeling Sessions ....................................................................... 15
Session Roles............................................................................. 16
Sample IDEF1X Modeling Methodology ......................................................... 17
Modeling Architecture ......................................................................... 18
Logical Models................................................................................ 18
Entity Relationship Diagram ............................................................... 19
Key-Based Model ......................................................................... 19
Fully-Attributed Model..................................................................... 19
Physical Models............................................................................... 19
Transformation Model ..................................................................... 20
DBMS Model .............................................................................. 20
Chapter 3: Logical Models 21
How to Construct a Logical Model .............................................................. 21
Entity Relationship Diagram ................................................................... 22
Entities and Attributes Defined............................................................. 23
Logical Relationships ...................................................................... 24
Many-to-Many Relationships ............................................................... 25
Logical Model Design Validation................................................................ 26
Data Model Example .......................................................................... 27
Chapter 4: The Key-Based Data Model 29
Key Based Data Model ........................................................................ 29
Key Types.................................................................................... 30
Entity and Non-Key Areas ................................................................. 30
Contents 5
