Catalog items are essentially described only by metadata; in fact, if there's a search box in such an application, it often only searches metadata.

目录项事实上就是通过元数据描述的；实际上，如果在这样的应用程序中有一个搜索框，那么它通常只搜索元数据。

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DB2 takes these input values and searches the catalog tables to identify XML schema needed to validate XML document.

DB 2接受这些输入值并搜索目录表以识别验证XML文档所需的XML模式。

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Stanford University was an early customer to allow easy searches of its Socrates online library catalog.

FORBES: Finding Meaning In A Google World

The searches may be conducted on-site at the library or via an online catalog, which will be accessible via the library's World Wide Web site at www.loc.gov.

CNN: LOC Web site to offer access to holdings