【OCP认证12c题库】CUUG 071题库考试原题及答案（25）

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Evaluate the following SQL statement:

ALTER TABLE hr.emp

SET UNUSED (mgr_id);

Which statement is true regarding the effect of the above SQL statement?

A) Any views created on the EMP table that include the MGR_ID column would be automatically modified and remain valid.

B) Any constraints defined on the MGR_ID column would be removed by the above command.

C) Any synonym existing on the EMP table would have to be re-created.

D) Any index created on the MGR in column would continue to exist until the DROP UNUSED COLUMNS command is executed.

Answer：B

(注意：列一旦被设置为 unused 以后，基于该列的约束、索引都被删除，同时相关的视图被无法访问。)

【OCP认证12c题库】CUUG 071题库考试原题及答案（25）

标签：effect   cal   ons   alt   answer   following   考试   exe   ocp   

原文地址：http://blog.51cto.com/13854012/2352744