Purpose of database systems are to store the organizational information in computer systems such a way that the data can be manipulated easily by it’s user.
Consider part of a savings bank enterprise that keeps information about all customers and savings accounts. One way to keep the information on a computer is to store it in permanent system files to allow users to manipulate the information, the system has a number of application programs that manipulate the files including
- A program to debit or credit an account
- A program to add a new account
- A program to find the balance of an account
- A program to generate monthly statements
These application programs have been written by system programmers in response to the needs of the bank organization.
New application programs are added to the system as the need arises. For example, suppose that new government regulations allow the savings bank to offer checking accounts.
The typical file processing system just described is supported by a conventional operating system. Permanent records are stored in various files, and different application programs are written to extract records from, and to add records to the appropriate files.