Enhanced-ER (EER) Model Concepts: Specialization and Generalization
It is the diagrammatic technique to display the following concepts:
- Subclass and Superclass
- Specialization and Generalization
- Union and Category
- Aggregation
Generalization
It works on the principle of a bottom-up approach. In Generalization, lower-level functions are combined to form higher-level function which is called entities. This process is repeated further to make advanced-level entities.
In the Generalization, process properties are drawn from particular entities and thus we can create the generalized entity. We can summarize the Generalization process as it combines subclasses to form a superclass.
Example of Generalization –
Consider two entities Student and Patient. These two entities will have some characteristics of their own. For example, the Student entity will have Roll_No, Name, and Mob_No while the patient will have PID, Name, and Mob_No characteristics. Now in this example Name and Mob_No of both Student and Patient can be combined as a Person to form one higher-level entity and this process is called as Generalization Process.
Specialization
We can say that Specialization is the opposite of Generalization. In Specialization things are broken down into smaller things to simplify it further. We can also say that in Specialization a particular entity gets divided into sub entities and it’s done on the basis of it’s characteristics. Also in Specialization Inheritance takes place.
Example of Specialization –
Consider an entity Account. This will have some attributes consider them Acc_No and Balance. Account entity may have some other attributes like Current_Acc and Savings_Acc. Now Current_Acc may have Acc_No, Balance and Transactions while Savings_Acc may have Acc_No, Balance and Interest_Rate henceforth we can say that specialized entities inherits characteristics of higher level entity.
Difference b/w Generalization and Specialization
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