A functional index can specify different access methods that include B-Tree, R-Tree, and user-defined access methods.

函数索引可以指定各种不同的访问方法，包括B - Tree、r - Tree和用户定义的访问方法。

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Index options like UNIQUE and CLUSTER, and access methods like B-Tree, R-Tree and user-defined access methods can apply to both functional and non-functional indexes.

诸如unique和CLUSTER等索引选项，以及B - Tree、r - Tree等访问方法和用户定义的访问方法，可以同时应用于函数索引和非函数索引。

youdao

In this example we show you how to create a functional index that USES the R-Tree access method.

在本例中，我们将向您展示如何创建使用r - Tree访问方法的函数索引。

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The only evidence was cut into a tree and a fence: the letters C-R-O and the word Croatoan,C-R-O-A-T-O-A-N.

VOA: special.2009.08.17