A database administrator’s responsibilities can include the following tasks:

• Installing and upgrading the Oracle Database server and application tools.

• Allocating system storage and planning future storage requirements for the database system.

• Creating primary database storage structures (tablespaces) after application developers have designed an application.

• Creating primary objects (tables, views, indexes) once application developers have designed an application.

• Modifying the database structure, as necessary, from information given by application developers.

• Enrolling users and maintaining system security.

• Ensuring compliance with Oracle license agreements.

• Controlling and monitoring user access to the database.

• Monitoring and optimizing the performance of the database.

• Planning for backup and recovery of database information.

• Maintaining archived data on tape.

• Backing up and restoring the database.

• Contacting Oracle for technical support.

Ref.: http://download.oracle.com/docs/cd/B28359_01/server.111/b28310/dba001.htm#i1006120