| Purpose |
Defines an identity constraint of type xs:unique. The values of an identity constraint are extracted from an XML fragment that is validated against the parent element declaration. The values of an xs:unique identity constraint must be unique. For details of the construction of the tuples representing the values of an identity constraint, please see section 3.11.4 Identity-constraint Definition Validation Rules of the W3C documentation XML Schema Part 1: Structures. |
| Parent element | xs:element |
| Child elements | xs:annotation,
xs:field,
xs:selector |
| Attributes | id,
name |
| Name | Type | Description |
|---|---|---|
id |
xs:ID |
Assigns an identifier to the schema node. |
name |
xs:NCName |
The names of all identity constraints (xs:key, xs:keyref and xs:unique) must be unique within a schema document. An xs:unique identity
constraint can be referenced by an xs:keyref identity constraint that cites the name
of the xs:unique identity constraint
in the |
