2018年oracle认证OCP考试052新题解析-191

191.

User A executes this command:

SQL> ALTER TABLE oe.trans MOVE TABLESPACE tbs2;

While this is executing, user B executes this command:

SQL> DELETE FROM oe.trans WHERE tr_type='SL';

Which statement is true regarding the DELETE command?

A) It fails because the table is locked in SHARE ROW EXCLUSIVE mode.  B) It fails because rows are locked in EXCLUSIVE mode.

C) It deletes the rows.

D) It fails because rows are locked in SHARE mode.

E) It fails because the table is locked in EXCLUSIVE mode.

答案E

解析：当对table进行move操作时，查询v$locked_objects视图可以发现，表上加了exclusive lock，这就意味着，table在进行move操作时，我们只能对它进行select的操作，update和delete操作不可以。反之，当一个session对table进行非SELECT的DML操作且尚未commit时，另一个session中是不能对这个table进行move操作的，否则oracle会返回这样的错误信息：ORA-00054: 资源正忙，要求指定 NOWAIT。

 

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