REQUIREMENTS OF DATABASE

Requirements of database help in determining the prerequisites before storing the data in
the database. Following are the requirements for database management.

1) Non-redundancy
As already suggested, non-redundancy is beneficial in eliminating the contradictions and in saving storage space. Occasionally, amount of redundancy is acceptable such as when the need for data security or rapid access is paramount.

2) Data independence

This means that the data and the programs are independent, which means that the data can be moved or restructured without the need to make alterations to the programs. Similarly an enforced program change does not call for rearrangement of the data layout. If there is no data independency, then a program requiring more data items from a file necessitates rearranging it, and consequently other programs have to be modified to cope with the rearrangement of the file.

3) Program usage
A database needs to be usable by not only all the existing applications but also by all foreseeable applications. These are ambitious aims, but nonetheless a database must be open-ended so as to accept new sets of data items and change to the existing data item sets.

4) Data Inter-relationships
Data inter-relationships are necessary because of the fact that various applications use data in different ways. For example, one application may demand a link between an employee's name and his pension contribution, another between his tax payment and his previous employer. Requirements such as these impose stringent demands upon the database's accuracy, security and flexibility.

5) Common approach
Common approach is based on simplicity and understanding of data and programs. Although application programmers are not concerned with .the database's structure and techniques, a common approach simplifies the database control programs and facilitates the database administrator's work.