OCM OCM Database Administration & SQL

Question 1

Which Oracle feature allows you to recover a dropped table without restoring from a backup?

Accepted Answer

Flashback Table

Answer

Flashback Table uses the Oracle Recycle Bin to restore a dropped table to its state before the DROP command.

Question 2

What is the purpose of the UNDO tablespace in Oracle Database?

Accepted Answer

Providing read consistency and supporting transaction rollback

Answer

The UNDO tablespace stores before-images of modified data to support transaction rollback and provide consistent reads for concurrent queries.

Question 3

Which SQL hint forces the Oracle optimizer to use a full table scan instead of an index?

Accepted Answer

/*+ FULL(table) */

Answer

The FULL hint instructs the Cost-Based Optimizer to perform a full table scan on the specified table, bypassing available indexes.

Question 4

In Oracle, what does the PCTFREE storage parameter control?

Accepted Answer

Percentage of block space reserved for future row updates

Answer

PCTFREE specifies the percentage of each data block kept free to accommodate future updates that increase the size of existing rows.

Question 5

Which Oracle background process is responsible for writing dirty buffers from the buffer cache to datafiles?

Accepted Answer

DBWR

Answer

DBWR (Database Writer) writes modified (dirty) buffers from the database buffer cache to the datafiles on disk.

OCM - Oracle Certified Master Practice Test