Database Systems: Concepts, Design and Applications

2.4. Data Independence

Data independence (briefly discussed in Section 1.8.5 (b)) is a major objective of implementing DBMS in an organisation. It may be defined as the immunity of application programs to change in physical representation and access techniques. Alternatively, data independence is the characteristics of a database system to change the schema at one level without having to change the schema at the next higher level. In other words, the application programs do not depend on any one particular physical representation or access technique. This characteristic of DBMS insulates the application programs from changes in the way the data is structured and stored. The data independence in achieved by DBMS through the use of the three-tier ...