053-230

You plan to use Flashback Drop feature to recover a dropped table SALES_EMP. No other table with the same name exists in the schema.
You query RECYCLEBIN and find multiple entries for the SALES_EMP table as follows: You then issue the following statement to recover the table:

SQL> FLASHBACK TABLE sales_emp TO BEFORE DROP;
What would be the outcome of the precedent statement?
A. It retrieves the latest version of the table from the recycle bin
B. It retrieves the oldest version of the table from the recycle bin
C. It retrieves the version of the table for which undo information is available
D. It returns an error because the table name is not specified as per the names in the OBJECT_NAME column

D错误,可以不用指定对象名,指定相关表名也是可以的。
C错误,FLASHBACK TABLE...TO BEFORE DROP是基于回收站,并不是基于undo的。
当有多个对象公用一个表名时,使用FLASHBACK TABLE..TO BEFORE DROP,最新删除的表的条目会从回收站恢复。B错,A对
查询回收站中的对象:
SELECT object_name,original_name,createtime FROM recyclebin;

 

posted @ 2017-11-16 14:46  巴啦啦大魔王  阅读(80)  评论(0编辑  收藏  举报