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XML Schema field Element


XML Schema Reference Complete XML Schema Reference

Definition and Usage

The field element specifies an XPath expression that specifies the value used to define an identity constraint.

Element Information

  • Parent elements: key, keyref, unique

Syntax

<field
id=ID
xpath=XPath expression
any attributes
>

(annotation?)

</field>

(The ? sign declares that the element can occur zero or one time inside the field element)

Attribute Description
id Optional. Specifies a unique ID for the element
xpath Required. Identifies a single element or attribute whose content or value is used for the constraint
any attributes Optional. Specifies any other attributes with non-schema namespace

Example 1

The following example shows a field element that specifies the "userID" attribute as the field to use for the identity constraint:

<xs:field xpath="@userID"/>

XML Schema Reference Complete XML Schema Reference