Database Systems: Concepts, Design and Applications

10.1. Introduction

Relational database tables derived from ER models or from some other design method, suffer from serious problems in terms of performance, integrity and maintainability. A large database defined as a single table, results into a large amount of redundant data. Storing of large numbers of values of redundant nature can result in lengthy search operations for just a small number of target rows. It can also result in long and expensive updates. In other words, it becomes generally inefficient, error-prone and difficult in managing this large number of values. Fig. 10.1 illustrates a situation of a large single database of relation STUDENT-INFO (an example from Fig. 9.15 (a) of the previous chapter 9) with redundant data.

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