2.2.3.3 unsignedIntOrEmpty Simple Type

The unsignedIntOrEmpty simple type represents a value that can either be an xs:unsignedInt type, as specified in [XMLSCHEMA2/2] section 3.3.22, or an empty value.

 <xs:simpleType name="unsignedIntOrEmpty">
   <xs:union memberTypes="xs:unsignedInt EmptyVal"/>
 </xs:simpleType>