5 - Database Design

Abstract

This chapter discusses the designing of database. Databases with different data models have different structures for representing data; with relational databases, the fundamental data structures to provide such representations calling relational tables. It is the responsibility of the database administrator (DBA) to perform this design, assigning the related data items of the database to columns of tables in a manner that preserves desirable properties. The most important test of logical design is that the tables and attributes faithfully reflect interrelationships among objects in the real world. The DBA starts by studying some real-world enterprise, such as a wholesale order business, a company personnel office, or a college registration department, whose operation needs to be supported on a computerized database system. One of the major features of logical database design is the emphasis it places on the rules of interrelationships among data items. The naive user often sees a relational table as made up of a set of descriptive columns, one column much like another. The interrelationships among columns in relational tables must be understood at a reasonably deep level to properly appreciate some constraints.