The Enhanced Entity-Relationship (EER) model is an extension of the traditional Entity-Relationship (ER) model, designed to handle more complex data relationships in database design. It introduces additional concepts to represent real-world complexities more accurately.
Key features of the EER model include:
- Specialization: The process of defining subtypes from a general entity. For example, a Vehicle entity can be specialized into Car and Truck.
- Generalization: The reverse process of combining multiple entities into a more general entity. For example, Manager and Employee can be generalized into a single Person entity.
- Aggregation: Representing a relationship between relationships as a higher-level abstraction.
- Subtypes and Supertypes: Entities can have hierarchical relationships, with supertype entities having common attributes for their subtypes.
- Categories: Allowing entities to belong to multiple different entity sets.
The EER model helps in representing complex real-world systems more naturally and is used in advanced database design