Normalisation

Abstract

Normalisation was first introduced by Codd in his seminal paper on the Relational Model. It is concerned with designing tables so that update anomalies and data redundancy in particular are resolved. Although normalisation, or functional dependency, theory has evolved with the Relational Model, the techniques are used for logical rather than physical database design. Thus the underlying database need not be relational (or even a database for that matter). Indeed normalisation has been used in methods such as SSADM long before Relational Database Systems became commercially available.