Chapter 6 - Normalization

Abstract

This chapter introduces the process of normalization, through which such relations are created that they avoid most of the problems that arise from bad relational design. There are at least two ways to approach normalization. The first is to work from an entity relationship (ER) diagram. If the diagram is drawn correctly, then there are some simple rules that can be used to translate it into relations that avoid most relational design problems. However, the drawback to this approach is that it can be difficult to determine whether or not the design is correct. The second approach is to use the theoretical concepts behind good design to create relations. This is a bit more difficult than working from an ER diagram, but it often results in a better design. In practice, it is practical and common to use a combination of both approaches. First, an ER diagram is created and used to design relations. Then, those relations are checked against the theoretical rules for good design and necessary changes are made to meet the rules.