Expressing UML class diagrams properties with OCL

The Unified Modeling Language UML is a complex language offering many modeling features. Especially the description of static structures with class diagrams is supported by a rich set of primitives. This paper shows how to transfrom UML class diagrams involving cardinality constraints, qualifiers, association classes, aggregations, compositions, and generalizations into equivalent UML class diagrams employing only binary associations and OCL constraints. Thus we provide a better understanding of UML features. By reducing more complex features in terms of basic ones, we suggest an easy way users can gradually extend the set of UML elements they commonly apply in the modeling process.