The EER Model
See also: ER Modelling and UML ModellingThe EER model includes all of the concepts introduced by the ER model. Additionally it includes the concepts of a subclass and superclass (Is-a), along with the concepts of specialization and generalization. Furthermore, it introduces the concept of a union type or category, which is used to represent a collection of objects that is the union of objects of different entity types.
Read more about this topic: Enhanced Entity-Relationship Model
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