15.2.44. XML Schema keyref element

Definition and usage ¶

The keyref element specifies that the value of an attribute or element (or set of values) corresponds to the value of a specified key or unique element.

The keyref element must contain the following elements in order:

There must be one and only one selector element.

The selector element contains an XPath expression that specifies a set of elements in which the value specified by field must be unique.

Element information ¶

父元素: Element

Grammar ¶

<keyref
id=ID
name=NCName
refer=QName
*any attributes*
>
(annotation?,(selector,field+))
</include>

(? The symbol declares that in the key element, the element can appear zero or once, and the + symbol declares that the element must appear one or more times. )

Attribute	Description
Id	Optional. Specifies the unique ID of the element.
Name	Necessary. Specifies the name of the key element.
Refer	Necessary. Specifies the name of the key or unique element defined in the schema (or other schema indicated by the specified namespace). The refer value must be a qualified name (QName). Types can include namespace prefixes.
Any attributes	Optional. Specifies any other attributes with the non-schema namespace.

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