usage
Defines the intended usage of the query item.
Content model
Content type is NMTOKEN.
The possible values of this element are restricted to the following.
- unknown
Specifies that the usage is not known.
- identifier
Specifies that the object is to be treated as an identifier.
- fact
Specifies that the object is to be treated as a fact
- attribute
Specifies that the object is to be treated as an attribute.