Subject Scheme Map
A Subject Scheme Map allows you to create custom controlled attribute values and to manage metadata. Subject scheme maps use a key definition to define a collection of controlled values rather than a collection of topics. The highest level of map that uses the set of controlled values must reference the subject scheme map in which those controlled values are defined.
A controlled value is a keyword that can be used as a value in a metadata attribute. For
example, the @audience metadata attribute may take a value that identifies
the user group associated with a particular content unit (for medical equipment, that might
include therapist, oncologist, surgeon, radiologist, and so
on).
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