Entity Relationship Modelling

Abstract

In this chapter as well as in chapters 6 and 7 we cover the area of relational database design. Although database design can be regarded as falling within the scope of Systems Analysis, important design techniques have been influenced by the Relational Model. Normalisation in particular, covered in chapter 6, was introduced by Codd in his paper on the Relational Model. There are two aspects to relational database design. The first is the design of the relations (or tables): here the objective is to decide what data is stored in which table and to identify the primary keys for each table. The second aspect of design is that of program design: that is specifying the programs that operate on the tables. In relational systems these two activities are quite separate and can be undertaken independently. In this book we only cover the design of relations and not program design.