Final answer:
Enhanced Entity Relationship (EER) models extend the capabilities of ER models to better represent real-world complexities through subclass and superclass relationships, attribute inheritance, and additional notation, as well as incorporating associative entities, generalization, specialization, advanced constraints, and complex relationships.
Step-by-step explanation:
The question pertains to Enhanced Entity Relationship (EER) models, an advanced version of Entity Relationship (ER) models used in database design. An EER model includes all the features of an ER model along with additional concepts that are designed to more accurately model complex real-world scenarios. The true statements about the Enhanced Entity Relationship model include:
- Subclass and Superclass Relationships: EER models allow entities to be organized into a hierarchy where subclasses inherit attributes and relationships from their super classes.
- Attribute Inheritance: Attributes defined in a superclass are automatically inherited by its subclasses, enabling reuse and reducing redundancy.
- Additional Notation: EER diagrams use extra symbols and notation to represent specialized constructs like generalization, specialization, and categories.
- Associative Entities: EER models can include entities that represent the association between other entities (also known as 'relationship entities').
- Generalization and Specialization: These mechanisms allow the model to express hierarchical relationships between entities where subclasses can be more specific versions of a superclass.
- Advanced Constraints: EER models can enforce more complex constraints, such as participation constraints and disjoint constraints, which are not typically present in standard ER models.
- Complex Relationships: The EER model supports more complex relationships, including those involving multiple entities (n-ary relationships).