Role and Functions of the database Administrator:

One of the main reasons for using DBMS is to have central control of both the data and the programs that access those data. A person who has such central control over the system is called a database administrator (DBA). The functions of DBA include:

  • Schema Definition: The DBA creates the original database schema by executing a set of data definition statements in the DDL.


  • Storage structure and access-method definition.
  • Schema and physical-organization modification: The DBA carries out changes to the schema and physical organization to reflect the changing needs of the organization, or to later the physical organization to improve performance.


  • Granting of authorization for data access: By granting different types of authorization, the database administrator can regulate which parts of the database various users can access. The authorization information is kept in a special system structure that the database system consults whenever someone attempts to access the data in the system.
  • Routine maintenance: Examples of the database administrator’s routine maintenance activities are:
      • Periodically backing up the database, either onto tapes or onto remote servers, to prevent loss of data in case of disasters such as flooding.
      • Ensuring that enough free disk space is available for normal operations, and upgrading disk space as required.
      • Monitoring jobs running on the database and ensuring that performance is not degraded by expensive tasks submitted by some users.