R154 - modelint/shlaer-mellor-metamodel GitHub Wiki

R154 / 1:M

Association Reference refers toward exactly one Perspective

Perspective is reference direction of one or many Association Reference

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A Perspective is a view toward some Class in an Association. An Association Reference refers to the Identifier of that same Class.

We often characterize this direction by saying that an Association Reference refers along (toward) a Perspective.

For an Association between two different Classes it is convenient to just specify the Class being referenced.

This doesn't help much when we have a reflexive Association since both directions land on the same Class. It is in this case that it is important to specify which Perspective is being referenced.

images/formalization-subsystem/R154-5.png

The same Perspective (S) is the target of both T and P References in the case of a symmetric reflexive Association.

images/formalization-subsystem/R154-10.png

Formalization

Association Reference.(Rnum, Domain, Perspective) -> Perspective.(Rnum, Domain, Side)