An index only scan is an index access that is not followed by a table access because the index itself contains all the requested data.

仅扫描索引是未包含表访问的索引访问，因为索引本身包含了所有被请求的数据。

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Typically, a non-matching index scan is chosen by the optimizer when the underlying index provides benefits such as index-only access, avoids sort, or some similar benefit.

通常情况下，在基础索引提供好处(如唯一索引访问、避免排序或一些类似的好处)时，可通过优化器选择非匹配索引扫描。

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There is no FETCH or table node shown in the access path graph because it is an index-only scan.

因为其是一个唯一索引扫描，所以在访问路径图中不显示FETCH或表节点。

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The option can be used in non matching index scans in a screening fashion and as part of index-only access.

该选项以筛选的方式用于非匹配索引扫描，且是仅索引访问的一部分。

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You may also need to design indexes to avoid data sort and to provide index only access.

您也许还要设计索引以避免数据排序并提供只带索引的访问。

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Note: Regardless of the user permissions that built the index, by default search results will only show content that the user performing the search has access to.

注：不考虑用户构建索引的权限，默认情况下，搜索结果将只显示用户有权执行的搜索内容。

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Indexes that will provide index-only access for the SQL statement.

为sql语句提供进索引访问的索引。

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Since both LASTNAME and DEPTNO are part of the index, we will get index-only access.

因为LASTNAME和DEPTNO都是索引的一部分，我们将获得仅限索引的访问。

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Since DB2 will only use the index the "traditional" way for index-only access, the rows will be returned just like our index data, in groups of identical LASTNAMEs in random order.

因为DB 2仅将以“传统”方式使用索引，以实现仅限索引的访问，各行将像我们的索引数据一样，在同样的LASTNAME小组以随机形式返回。

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Keep in mind that making every query an index-only access is not prudent or even possible.

请记住：使每个查询成为仅索引访问是不谨慎，甚至也是不可能的。

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You might add a column to an existing index to get index-only access for a portion of the query's processing.

可以在现有的索引中添加列，让查询处理的一部分只访问索引。

youdao

You might add a column to an existing index to get index-only access for a portion of the query's processing.

可以在现有的索引中添加列，让查询处理的一部分只访问索引。

youdao