What are the roles and responsibilites of Database Administrator (DBA) ?

Following are the roles and responsibilities of Database Administrator:

• Installing and updating the Oracle server and application tools.
• Allocating system storage and planning future storage requirements for the database system.
• Creating primary database storage structures (table spaces) after application developers have designed an application.
• Creating primary objects (tables, views, indexes ) etc once application developers have designed an application.
• Modifying the database structure, as necessary from information giveny by application developers.
• Enrolling users and maintinging system security.
• Ensuring compliance with your oracle license agreements.
• Controlling and monitory user access to the database. 
• Monitoring and optimizing the performance of the database.
• Planning for backup and restoring the database. 
• Contacting Oracle corporation for technical support.