Learn online DBMS “Need of Database Management System” Lesson 2

Need for a Database
In Traditional file processing, data is stored in the form of files. A number of application programs are written by programmer’s to insert, delete, modifyand retrieve data from these files. New application programs will be added to the system as the need arises. For example, consider the Sales and Payroll departments of a company. One user will maintain information about all the salespersons in the Sales department in some file say File1 and another user will maintain details about the payroll of the salesperson in a separate file say File2 in the Payroll Department as shown in Figure 3.

Although both the departments need information about the salesperson but they will store information about the salesperson in different files and will use different application programs to access those filesand this would result in:
1. Data Redundancy – Same information is stored in more than one file. This would result in wastage of space.
2. Data Inconsistency – If a file is updated then all the files containing similar information must be updated else it would result in inconsistency of data.
3. Data Isolation – For new application programs, it might be difficult to retrieve the required data which might be stored in different files.
4. Lack of Data Integration – As data files are independent, accessing information out of multiple files becomes very difficult.
Database approach overcomes these problems and also adds a lot of advantages as discussed later. In database approach a single repository of data is maintained which is accessed by different users as per their needs.