SOPES — Navigation Constraint modelling

Annex A - Navigation Constraint modelling should include disallowed cardinality values for the subtended constraint evaluation Wrapper as well as an explanation of the acceptable uses of NULL as it concerns the Wrapper Attribute‘s value.

These explanations are to be added to section A.2.9.2 Navigation Constraints

The Wrapper containing the evaluation attribute (e.g., Point) on a navigation constraint must have a multiplicity of 1 (/1..1) within the data pattern. In reference to Figure A.12 and Table A.3 both Point and Location are constraint evaluation Wrapper instances and thus are required to have a cardinality of 1..1.

It should be noted that the Wrapper Attribute which holds the value must comply with the model's domain constraints and as such it is possible that the value held by the Wrapper Attribute could properly be expressed as NULL.