System Analysis and Design, Fifth Edition

CHAPTER 6

DATA MODELING

A data model describes the data that flow through the business processes in an organization. During the analysis phase, the data model presents the logical organization of data without indicating how the data are stored, created, or manipulated so that analysts can focus on the business without being distracted by technical details. Later, during the design phase, the data model is changed to reflect exactly how the data will be stored in databases and files. This chapter describes entity relationship diagramming, one of the most common data modeling techniques used in industry.

OBJECTIVES

• Explain the rules and style guidelines for creating entity relationship diagrams.
• Create an entity relationship diagram.
• Describe the use of a data dictionary and metadata.
• Explain how to balance entity relationship diagrams and data flow diagrams.
• Describe the process of normalization.

CHAPTER OUTLINE

Introduction

The Entity Relationship Diagram

Reading an Entity Relationship Diagram

Elements of an Entity Relationship Diagram

The Data Dictionary and Metadata

Creating an Entity Relationship Diagram

Building Entity Relationship Diagrams

Advanced Syntax

Applying the Concepts at Tune Source

Validating an ERD

Design Guidelines

Normalization

Balancing Entity Relationship Diagrams with Data Flow Diagrams

Summary

Appendix 6A: Normalizing the Data Model

INTRODUCTION

During ...