XML Schema union Element
Complete XML Schema Reference
Definition and Usage
The union element defines a simple type as a collection (union) of values from specified simple data types.
Element Information
- Parent elements: simpleType
Syntax
<union
id=ID
memberTypes="list of QNames"
any attributes
>
(annotation?,(simpleType*))
</union>
id=ID
memberTypes="list of QNames"
any attributes
>
(annotation?,(simpleType*))
</union>
(The ? sign declares that the element can occur zero or one time inside the union element)
| Attribute | Description |
|---|---|
| id | Optional. Specifies a unique ID for the element |
| memberTypes | Optional. Specifies a list of built-in data types or simpleType elements defined in a schema |
| any attributes | Optional. Specifies any other attributes with non-schema namespace |
Example 1
This example shows a simple type that is a union of two simple types:
<xs:element name="jeans_size">
<xs:simpleType>
<xs:union memberTypes="sizebyno sizebystring" />
</xs:simpleType>
</xs:element>
<xs:simpleType name="sizebyno">
<xs:restriction base="xs:positiveInteger">
<xs:maxInclusive value="42"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="sizebystring">
<xs:restriction base="xs:string">
<xs:enumeration value="small"/>
<xs:enumeration value="medium"/>
<xs:enumeration value="large"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType>
<xs:union memberTypes="sizebyno sizebystring" />
</xs:simpleType>
</xs:element>
<xs:simpleType name="sizebyno">
<xs:restriction base="xs:positiveInteger">
<xs:maxInclusive value="42"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="sizebystring">
<xs:restriction base="xs:string">
<xs:enumeration value="small"/>
<xs:enumeration value="medium"/>
<xs:enumeration value="large"/>
</xs:restriction>
</xs:simpleType>
Complete XML Schema Reference
