XML Pocket Reference, 3rd Edition

Name

xs:selector

Attributes

xpath

An XPath location path used by the xs:unique, xs:key, or xs:keyRef element containing the xs:selector

xs:selector is used within xs:unique, xs:key, or xs:keyRef elements and stores an XPath location path. These expressions use a very simplified subset of XPath, permitting only abbreviated syntax for the child axis to be used. In place of explicit element names, the * expression may be used to match any name, and the prefix:* expression to match any name in a given namespace. // may be used for any descendant, but only at the beginning of the XPath. No predicates or attributes may be used. Multiple location paths may be stored in the xpath attribute, each separated by a vertical bar.