Binary Association - modelint/shlaer-mellor-metamodel GitHub Wiki

The term ‘binary’ means that there are exactly two Perspectives on this type of Association.

It does NOT mean that there are two Classes.

A reflexive Binary Association may be created on a single Class such that each of the two Perspectives is viewed from the same Class.

Here are two examples of Binary Associations. One is drawn between two Classes and the other is reflexive on a single Class.

There are still two distinct Perspectives in the reflexive case even though the multiplicity and conditionality happen to be the same.

No non-referential attributes