To show how very large systems can be described and managed in a decentralized manner. All of these methodologies are based on the object as the common building block and on the class as a common abstraction on the objects. There is a widespread feeling that existing methodologies could profitably be merged into a single one, and that the concepts and notation of the composite methodology could be standardized. We feel that such standardization will be premature. Static properties and relations are best expressed in terms of classes.
Examples are attributes and relations, most notably for expressing the inheritance relation.
Dynamic properties are best expressed in terms of objects. A future modeling standard should be built on a unified conceptual framework with sufficient expressive power to describe all interesting aspects of an object system within a single, integrated model. This conceptual framework combines the expressiveness of the object and the class. All information that can be expressed in a class-based model can he expressed in a role model. All information that can be expressed in an object-based model can be be expressed in the same role model.