Introduction

This section contains the following topics:

Overview

A database is a computer representation of information that exists in the real world. Like a painting, a database tries to imitate reality. Designing a database is an art form, and a successful database bears the mark of a thoughtful, creative designer.

For a given database problem, there may be several solutions. While some designs are clearly better than others, there is no right or wrong design. The structure of your database will therefore be determined not only by the requirements of the business but also by your individual style as a designer. As you develop and refine the design for a database, let your intuition be your guide.

The purpose of creating a database is to satisfy the information requirements of business application programs. Before users can run their application programs, the database administrator (DBA) must design and implement the corporate database. As the DBA or database designer, you are responsible for database design and implementation.

Data models

To design a database, you must develop two different data models:

The logical model describes all corporate information to be maintained in the database. This model represents the way the user perceives the data.
The physical model describes how the data is stored and accessed by the system. The physical design for a database builds on the logical model. During the physical design process, you tailor the logical design to specific application performance requirements and plan the best use of storage resources.

Iterative process

Creating a design for a database is an iterative process. After you have developed the logical and physical models, you need to review the design process and the available documentation with users in your corporation. As users make suggestions for improvement, you should make appropriate changes to the design. Review the design repeatedly until it is acceptable to the user community.