为了执行XML查询，DB 2 9引入了三个新的内部查询操作符，名为XSCAN、XISCAN和XANDOR。

To execute XML queries, DB2 9 introduces three new internal query operators called XSCAN, XISCAN, and XANDOR.

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要使用表子查询，需要使用SQL操作符将嵌入式查询与布尔表达式组合在一起。

To use a table subquery, you need to use an SQL operator to combine the embedded query with a Boolean expression.

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另外，DB 2可以利用新的查询和联结操作符以及新的索引处理技术，为涉及XML文档的查询提供更好的运行时性能。

In addition, DB2 can leverage new query and join operators, as well as new index processing techniques, to provide strong runtime performance for queries involving XML documents.

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