selector
Specifies an XML Path Language (XPath) expression that selects a set of elements for an identity constraint (unique, key, and keyref elements).
<selector id = ID xpath = a subset of XPath expression {any attributes with non-schema Namespace}…> Content: (annotation?) </selector>
Attributes
- id
- The ID of this element. The id value must be of type ID and be unique within the document containing this element.
Optional.
- xpath
- An XPath expression that is relative to the element being declared. This expression identifies the child elements (of the element being declared) to which the identity constraint applies.
Required.
Element Information
Number of occurrences | One time |
Parent elements | key, keyref, unique |
Contents | annotation |
Remarks
Selector ::= Path ( '|' Path )* Path ::= ('.//')? Step ( '/' Step )* Step ::= '.' | NameTest NameTest ::= QName | '*' | NCName ':' '*'
Note When using XPath, you must use fully qualified names. For example,myNS:localName
instead oflocalName
.
Example
The following fragment is a selector element that selects all expense elements with a field element that selects an approved attribute.
<selector xpath=".//expense"/> <field xpath="@approved"/>
See Also
XML Schema Reference (XSD) | XML Schema Elements
For more information, see the W3C XML Schema Part 1: Structures Recommendation at http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#element-selector.