XML Schema field Element
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"/>
Complete XML Schema Reference
