OCP-1Z0-051-V9.02-41题

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41. Which two statements are true regarding views? (Choose two.)

A. A subquery that defines a view cannot include the GROUP BY clause.

B. A view that is created with the subquery having the DISTINCT keyword can be updated.

C. A view that is created with the subquery having the pseudo column ROWNUM keyword cannot

be updated.

D. A data manipulation language ( DML) operation can be performed on a view that is created with

the subquery having all the NOT NULL columns of a table.

Answer: CD

答案解析：

参考：http://blog.csdn.net/rlhua/article/details/12790467

A错误，创建视图的子查询可以使用group by子句。

B错误，子查询中带有DISTINCT 不能对视图进行DML操作。

C正确，子查询中带有ROWNUM 关键字不能对视图进行DML操作。

D正确，所有非空列都可以进行DML操作。