ocp-498

最新推荐文章于 2024-11-08 15:26:17 发布

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最新推荐文章于 2024-11-08 15:26:17 发布

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分类专栏： OCP-1Z0-053

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本文探讨了在特定参数设置下创建不可见索引的行为。不可见索引不会被优化器默认使用，但在数据操作语言（DML）操作中仍然会被维护。若要在查询中利用不可见索引，则需明确指定提示。

QUESTION NO: 498？
View the Exhibit for some of the parameter settings. You start a session and issue the following
command:
SQL>CREATE INDEX emp_ename ON emp(ename) TABLESPACE users INVISIBLE;
What is the outcome of the above command?

A. The index is not used by the optimizer but is maintained during DML operations.
B. The index is not used by the optimizer and is not maintained during DML operations.
C. The index is used by the optimizer only if a hint is specified in the query statement and is maintained during
DML operations.
D. The index is used by the optimizer only if a hint is specified in the query statement but is not maintained
during DML operations.
Answer: A

查看的图表的一些参数设置。你启动一个会话，并发出以下命令：
上述命令的结果是什么？

A.优化器不使用索引，但在DML操作期间维护。（第三行值为假）