索引的层次和惟一性也会影响数据的访问速度。

The level and uniqueness of an index will also affect the speed of accessing data.

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索引的创建有助于避免对表进行不必要的扫描和排序，加速频繁执行的查询以及确保惟一性。

Creating indexes helps avoid unnecessary table scans and sorts, speeds up frequently executed queries, and ensures uniqueness.

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搜索、视图、惟一性和索引。

Search, views, uniqueness, and indexes.

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