Entity Evolution in ISA Hierarchies

• Authors: Antoni Olivé;Dolors Costal;Maria-Ribera Sancho
• Venue: ER '99 Proceedings of the 18th International Conference on Conceptual Modeling
• Year: 1999

In a conceptual schema that includes specializations and generalizations, and that allows multiple classification, an entity may be, at a given time, instance of one or more entity types. We call type configuration of an entity the set of entity types of which it is instance at some time. In this paper, we characterize the set of valid type configurations, taking into account the constraints defined by specializations and generalizations. We also analyze the problem of determining the valid evolution of the type configuration of entities in the context of IsA hierarchies. We describe the temporal features of entity types and the evolution constraints that influence entity evolution. In particular, we propose and define the specialization evolution constraints, which extend the classical distinction between static and dynamic entity types. Taking into account all these features and constraints, we characterize the set of valid type configuration transitions. In both cases, we tackle the problem for the general class of conceptual schemas, allowing multiple specialization, generalization and classification, as well as dynamic classification.