Enhanced ER Model

 

Enhanced ER Model (EER Model)

The Enhanced Entity-Relationship (EER) Model is an extension of the basic ER model. It includes additional concepts to represent more complex data structures and relationships in a database system.

While the ER model handles entities, attributes, and relationships, the EER model adds advanced features like specialization, generalization, inheritance, and categories. This makes it more powerful and suitable for designing large and complex databases.

🔹 Features of Enhanced ER Model

1️⃣ Specialization

Specialization is the process of dividing a higher-level entity into lower-level sub-entities based on specific characteristics.

Example:
Employee → Manager, Engineer

2️⃣ Generalization

Generalization is the opposite of specialization. It combines multiple entities with common features into a single higher-level entity.

Example:
Car and Bike → Vehicle

3️⃣ Inheritance

Sub-entities inherit attributes and relationships from their parent entity.

Example:
If “Person” has Name and Age, then “Student” and “Employee” inherit these attributes.

4️⃣ Categories (Union Types)

A category represents a subclass that is formed from more than one entity type.

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