Database Administration is implemented by a person or group of persons under the supervision of a knowledgeable person called the Administrator. This person is known as Database Administrator (DBA). DBA is responsible for supervising the creation, modification, and maintenance of the database. The DBA controls the database structure and sets up the definition for physical as well as the logical implementation of the database.
Role of DBA:
(i) Schema Definition : The original database schema is created by writing a set of definitions that are translated by the DDL compiler to a set of tables that are permanently stored in the data dictionary.
(ii) Storage structure and access method definition : Appropriate storage structure and access methods are created by writing a set of definitions that are translated by the data storage and definition language compiler.
(iii) 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 alter the physical organization to improve performance.
(iv) Granting of authorization for data access : DBA also maintains that the database is not accessible to unauthorized users. The DBA is responsible for granting permission to use the database and stores the profile of each user of a database. This profile describes the permissible activities of a user on that portion of the database which is authorized to him. The user profile can be used by the DBA to verify that a particular user is only allowed to perform a given operation on the database within the limited time frame.
(v) Routine maintenance : The DBA is responsible for defining procedures to recover data from failures due to human, natural or hardware malfunctioning with minimal loss. This recovery procedure would thus enable an organization to continue working with the available intact portion of the database.
(vi) Maintaining integrity : DBA ensures that appropriate measures are taken to maintain the integrity of a database. Integrity constraints are kept in a special system structure that is consulted by the database manager whenever an update takes place in the system.