Modeling Facets

Basics

Facets do not exist independently. They are defined as part of the simple type that they constrain.

• Each facet will have a kind.
• Each facet will have a value.
• Enumeration facets must have a definition.

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.

Simple type names

A simple type declares a facet:

• If the type contains enumerations, the name of the type must end with CodeSimpleType.
• All other simple types must have names that end with with SimpleType.

References

• NDR Section 11.1.2.3 - Code simple types