Chapter 1: Introduction

This section contains the following topics:

Data Modeling Concepts (see page 9)

Benefits of Data Modeling (see page 9)

Methods (see page 10)

Typographical Conventions (see page 10)

Data Modeling Concepts

While data modeling can be complex, this Methods Guide will help you understand data modeling and its uses. If you are just a beginner, you will understand enough to put the methods to work for you by the time you finish reading this guide.

Overall, this guide has the following purposes:

■To provide a basic level of understanding of the data modeling method used by CA ERwin DM that is sufficient to do real database design.

■To introduce some of the descriptive power and richness of the IDEF1X and IE modeling languages supported and to provide a foundation for future learning.

■Experienced IDEF1X or IE users can use this as a guide to the features of IDEF1X and IE supported, and the mapping between these methods.

Benefits of Data Modeling

Regardless of the type of DBMS you use or the types of data models you want to develop, modeling your database in CA ERwin DM has many benefits:

■Enables usage by database and application development staff to define system requirements and to communicate among themselves and with end-users.

■Provides a clear picture of referential integrity constraints. Maintaining referential integrity is essential in the relational model where relationships are encoded implicitly.

■Provides a logical RDBMS-independent picture of your database that can be used by automated tools to generate RDBMS-specific information. This way, you can use a single diagram to generate DB2 table schemas, as well as schemas for other relational DBMSs.

■Lets you produce a diagram summarizing the results of your data modeling efforts and generate a database schema from that model.

Chapter 1: Introduction 9

Methods

Methods

Two methods of data modeling are supported by CA ERwin DM, which include:

IDEF1X

The IDEF1X method was developed by the United States Air Force. It is now used in various governmental agencies, in the aerospace and financial industry, and in a wide variety of major corporations.

IE (Information Engineering)

The IE method was developed by James Martin, Clive Finkelstein, and other IE authorities and is widely deployed in a variety of industries.

Both methods are suited to environments where large-scale, rigorous, enterprise-wide data modeling is essential.

Typographical Conventions

This guide uses special typographic conventions to identify the user interface controls and key terms that appear in the text. The following table describes these conventions:

10 Methods Guide