TABLE OF CONTENTS In the methodology presented in Section 2.3.2, we used top-down approach that begins by identifying main entities and relationships. Once a database has been designed, the application of normalization techniques is intended to optimize its performance and storage needs.
The process of normalization is seen as a procedure or series of tests to determine whether it satisfies or violates the requirements of a given normal form (Codd, 1982). Four most commonly-used methodologies for database normalization will be presented in this section: first normal form (INF), second normal form (2NF), third normal form (3NF) and Boyce-Codd normal form (BCNF). The fourth normal form (4FN) and fifth normal form (5FN) are not very commonly used in practice, and will not be presented here. If interested the reader is advised to refer to the relevant literature given at the end of this chapter.
Normalization is defined as a technique for producing a set of relations with desirable properties, given the data requirements of an enterprise. Consequently, the process of normalization is a formal method that identifies relations based on their primary key (or candidate keys in the case of BCNF) and the functional dependencies among their attributes. Normalization supports database designers by presenting a series of tests that can be applied to individual relations so that a relational schema can be normalized to a specific form to prevent possible occurrence of update anomalies.
The purpose of database normalization is:
to minimize duplication (redundancy) of...
