XML Schema unique Element
Complete XML Schema Reference
Definition and Usage
The unique element defines that an element or an attribute value must be unique within the scope.
The unique element MUST contain the following (in order):
- one and only one selector element (contains an XPath expression that specifies the set of elements across which the values specified by field must be unique)
- one or more field elements (contains an XPath expression that specifies the values that must be unique for the set of elements specified by the selector element)
Element Information
- Parent elements: element
Syntax
<unique
id=ID
name=NCName
any attributes
>
(annotation?,(selector,field+))
</unique>
(The ? sign declares that the element can occur zero or one time inside the unique element)
| Attribute | Description |
|---|---|
| id | Optional. Specifies a unique ID for the element |
| name | Required. Specifies a name for the element |
| any attributes | Optional. Specifies any other attributes with non-schema namespace |
Complete XML Schema Reference
