written 7.6 years ago by | • modified 2.6 years ago |
Mumbai University > Computer Engineering > sem 4> database management system
Marks: 5M
Year: May16
written 7.6 years ago by | • modified 2.6 years ago |
Mumbai University > Computer Engineering > sem 4> database management system
Marks: 5M
Year: May16
written 7.6 years ago by |
i. Coordinates all the activities of the database system. The database administrator has a good understanding of the enterprise's information resources and needs.
ii. Database administrator's duties include:
a. Schema definition:
The DBA creates the original database schema by executing a set of data definition statements in the DDL.
b. Storage structure and access method definition.
c. 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.
d. Granting user authority to access the database:
By granting different types of authorization, the database administrator can regulate which parts of the database various users can access.
e. Specifying integrity constraints.
f. monitering performance and resposding to change its requirement
1. Schema Definition: The DBA definition the logical Schema of the database.A Schema refers to the overall logical structure of the database. According to this schema, database will be developed to store required data for an organization.
2. Storage Structure and Access Method Definition: The DBA decides how the data is to be represented in the stored database.
3. Assisting Application Programmers: The DBA provides assistance to application programmers to develop application programs.
4. Physical Organization Modification: The DBA modifies the physical organization of the database to reflext the changing needs of the organization or to improve performance.
5. Approving Data Access: The DBA determines which user needs access to which part of the database. According to this,various types of authorizations are granted to different users.
6. Monitoring Performance: The DBA monitors performance of the system.The DBA ensures that better performance is maintained by making changes in physical or logical schema if required.
7. Backup and Recovery: Database should not be lost or damaged. The DBA ensures this periodically backing up the database on magnetic tapes or remote servers. In case of failure, such as virus attack database is recovered from this backup.