OCP考试题库以前是比较稳定的,但在2018年随着oracle的调整,不断的有新题出现,增加考试的难度,对此,我们专门收集整理了071的考试真题,分享给大家。
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071题库分享-第39题、choose two
Which two statements are true regarding views? (Choose two.)
A) A simple view in which column aliases have been used cannot be updated.
B) The OR REPLACE option is used to change the definition of an existing view without dropping and re-creating it.
C) The WITH CHECK OPTION constraint can be used in a view definition to restrict the columns displayed through the view.
D) Rows added through a view are deleted from the table automatically when the view is dropped.
E) Rows cannot be deleted through a view if the view definition contains the DISTINCT keyword.
F) A subquery used in a complex view definition cannot contain group functions or joins.
Answer:BE
(解析:
只要是简单视图,使用别名的列是可以使用 UPDATE 命令更新的。
WITH CHECK OPTION 用于限制通过视图更改基表的条件,禁止更改不包含在子查询条件里的行。)
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