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In Computer Science, the Enhanced Entity-Relationship (EER) model is a high-level or conceptual data model incorporating extensions to the original Entity-relationship (ER) model, used in the design of databases. It was developed by a need to reflect more precisely properties and constraints that are found in more complex databases, such as in engineering design and manufacturing (CAD/CAM), telecommunications, complex software systems and Geographic Information Systems (GIS).

[edit] The EER Model

See also: ER Modelling and UML Modelling

The EER Model includes all of the modelling concepts introduced by the ER model. Additionally it includes the concepts of a subclass and superclass, along with the concepts of specialisation and generalisation. 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.

[edit] References

• Elmasri, Ramez; Shamkant B.Navathe (2007). Fundamentals of Database Systems, 5th edition, Boston: Pearson/Addison Wesley. ISBN 978-0-321-36957-4.