Facets do not exist independently. They are defined as part of the simple type that they constrain.
A simple type that defines month codes will declare 12 facets:
- The facet kinds will each be enumeration.
- The facet values will be JAN, FEB, MAR, etc.
- The facet definitions will be January, February, March, etc.
Keep in mind that overly-restrictive facets limit reusability, particularly in NIEM release schemas. For example, facets that restrict a string to the number of characters allowed in a corresponding database field may limit other users with different systems.
A simple type declares a facet:
|NDR 9-14||REF, EXT||Enumeration has data definition|
|NDR 9-13||REF||No use of fixed on simple type facets|
|NDR 10-17||REF, EXT||Name of code type ends in CodeType|
|NDR 10-18||REF, EXT||Code type corresponds to a code list|
|NDR 11-7||REF, EXT||Name of a code simple type ends in CodeSimpleType|
|NDR 11-8||REF, EXT||Code simple type corresponds to a code list|