Oracle OCP原创试题解析（40）

ITAA-OCM

You are working on an online transaction processing (OLTP) system. You notice that a PL/SQL procedure got executed twice at 2) 00 p.m. This has incorrectly updated the EMP_SAL table. How would you revert the table to its state at 2) 00 p.m.?

A) Perform point-in-time recovery to 2: 00 p.m.

B) Use Flashback Table feature to revert the changes.

C) Restore the entire database from the recent backup and open it.

D) Issue the rollback statement with system change number (SCN).

Answer: B

基于时间点得数据库恢复（point-in-time recovery）需要关闭数据库，启动到mount状态下应用归档日志进行恢复。因为是OLTP系统，所以A不合题意。

闪回表可以将单独一个表恢复到某个时间点而不影响其他表的数据，所以B正确。

C不能恢复到2:00的状态，D中rollback只能回滚未提交的事务。