Subject: Oracle DBA I.) True/False : – Choose “True” or “False” and give explana
ID: 3850422 • Letter: S
Question
Subject: Oracle DBA
I.) True/False: – Choose “True” or “False” and give explanation
1. One Oracle listener can listen for more than one database instance.
2. Oracle dispatcher can handle multiple user sessions.
3. Oracle shared SQL area is usually held in PGA.
4. A foreign key table can have multiple parents.
5. Oracle shared pool is used for large database backup and restore operations
6. You can use pseudocolumn to specify a default value for a column
7. SMON performs recovery at instance shutdown.
8. To Rename a column you use UPDATE TABLE command.
9. A foreign key constraint prevents the deletion of the child table.
Explanation / Answer
1. true: - A listner can have assigned multiple listening addresses, from which multiple database instances can be processed.
2. True: - At a time multiple user sessions can co exist and one Oracle dispatcher can handle it via multiplexing the sessions.
3. False: - Shared SQL area is help in SGA i.e. System Global Area which is shared by all servers and background processes.
4. True: - A foreign key table can reference multiple tables provided, each foreign key can reference single parent table. So if it having multiple foreign keys, it can have multiple parent tables.
5. False: - For backup and restore operation large memory area is needed, So large pool of Oracle is used for this purpose.
6. True: - Pseudocolumns can be used as default value. eg. CURRVAL,NEXTVAL,SYSDATE etc
7. False: - SMON performs recovery at instance startup.
8. False: - Renaming a column is Data Definition operation. It is done using ALTER TABLE command
9. True: - deletion of child table rows are prevented unless ON DELETE CASCADE is used.