Enhanced ER-Diagram

Enhanced ER Model

 

Today’s time the complexity of the data is increasing so it becomes more and more difficult to use the traditional ER model for database modelling. To reduce this complexity of modelling we have to make improvements or enhancements were made to the existing ER model to make it able to handle the complex application in a better way. Enhanced entity-relationship diagrams are advanced database diagrams very similar to regular ER diagrams which represent requirements and complexities of complex databases. It is a diagrammatic technique for displaying the Sub Class and Super Class;
Specialization and Generalization.

Generalization
In generalization, a number of entities are brought together into one generalized entity based on their similar characteristics. For example, pigeon, sparrow, crow and dove can all be generalized as Birds

 

 

 

 

Specialization

Specialization is the opposite of generalization. In specialization, a group of entities is divided into sub-groups based on their characteristics. Take a group ‘Person’ for example. A person has name, date of birth, gender, etc. These properties are common in all persons, human beings. But in a company, persons can be identified as employee, employer, customer, or vendor, based on what role they play in the company.

 

 

 

Similarly, in a school database, persons can be specialized as teacher, student, or a staff, based on what role they play in school as entities.
Inheritance
Inheritance is an important feature of Generalization and Specialization. It allows lower-level entities to inherit the attributes of higher-level entities

 

 

 

For example, the attributes of a Person class such as name, age, and gender can be inherited by lower-level entities such as Student or Teacher.