GENERALIZATION SPECIALIZATION AND ROLE IN OBJECT-ORIENTED CONCEPTUAL MODELING

The ''IS A''-relationship and the mechanism of inheritance are powerfu l concepts that help to reduce complexity of models and redundancy in specifications. However, in the area of conceptual modeling, it seems that current Object Oriented Analysis methods put most emphasis on the structural aspects of the ''IS A''-relationship while inheritance and sharing of behaviour are often not or ill-defined. This paper investi gates how attribute sharing, behaviour sharing and subset hierarchies can be combined into a sound ''IS A''-modelling concept that guarantee s universal substitutability. Decision criteria on the use of generali zation/specialization are discussed and a formal taxonomy of processes corresponding to the generalization/specialization hierarchy is prese nted.