DATABASE ADMINISTRATOR (DBA)

   The person who have central control of both data and the programs that access those data in the database is called the Database Administrator (DBA).

THE FUNCTIONS OF THE DBA:

SCHEMA DEFINITION:

   The DBA creates the original database schema (schema means arrangement of data) by writing a set of definitions that is translated by a special language called a Data - Definition Language (DDL).The result of compilation of DDL statements is a set of tablets of database that is stored permanently in a special file called data dictionary, or data directory which contains metadata - that is,data about data.

STORAGE STRUCTURE AND ACCESS -METHODS:

    The DBA creates storage structure and access methods by writing a set of definitions,which is translated by the Data Definition Language Compiler.

SCHEMA & PHYSICAL ORGANISATION MODIFICATION:

   The DBA carries out changes to the schema and physical organisation to make the changing in physical organisation to improve performance.

GRANTING OF AUTHORIZATION OF DATA ACCESS:

   The DBA grants permission for accessing different parts of the database to various users.

INTEGRITY- CONSTRAINT SPECIFICATION:

   The data values stored in the database must satisfy a consistent constraint (condition) specified only by DBA,Known as integrity constraint.So that,the data values stored in the database must be according to Integrity Constraints (conditions).

ROUTINE MAINTENANCE:

•    DBA periodically updates the database,to prevent loss of data in case of disasters.
•    DBA ensures that there is enough free space available for doing normal operations.
•    DBA monitors all the jobs running on the database and ensure that performance is not              degraded by very expensive tasks submitted by some users.