Generalization
Generalization is the process of extracting common properties from a set of entities and creating a generalized entity from it. It is a bottom-up approach in which two or more entities can be generalized to a higher-level entity if they have some attributes in common. For Example, STUDENT and FACULTY can be generalized to a higher-level entity called PERSON as shown in Figure 1. In this case, common attributes like P_NAME, and P_ADD become part of a higher entity (PERSON), and specialized attributes like S_FEE become part of a specialized entity (STUDENT).
Generalization is also called as ‘ Bottom-up approach”.
Generalization, Specialization and Aggregation in ER Model
Using the ER model for bigger data creates a lot of complexity while designing a database model, So in order to minimize the complexity Generalization, Specialization, and Aggregation were introduced in the ER model and these were used for data abstraction in which an abstraction mechanism is used to hide details of a set of objects. Some of the terms were added to the Enhanced ER Model, where some new concepts were added. These new concepts are:
- Generalization
- Specialization
- Aggregation