例如，可以使用SQL编写联合查询，并可以指定对产品信息的访问。

For example, a federated query might be written in SQL and might specify access to product information.

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查询此xml树并返回一个产品对象。

Query the XML tree and return a products object.

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可以通过查询字符串参数来指定要查看的该类别的产品。

The category's products to view would be specified by a querystring parameter.

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