Key Difference – Generalization vs Specialization in DBMS
The key difference between Generalization and Specialization in DBMS is that Generalization is the process of combining lower level entities to produce the higher-level entity while Specialization is the process of dividing the higher-level entity into lower level entities.
Every organization need to store data according to the requirement. There is various type of data, and there should be a mechanism to organize them. A Database Management System (DBMS) can be used to store, update, manage and retrieve data efficiently. Before storing the data in the database, there should be a visual representation of the database to be designed. An Entity Relationship (ER) diagram can be used to get the conceptual understanding of the database. The ER diagram is based on ER model. With the complexity of data, the ER model was developed further. It is known as an Enhanced Entity Relationship model (EER). The diagram based on EER model is called the Enhanced ER diagram. Generalization and Specialization are two concepts of Enhanced ER model that can be applied to draw EER diagram.
CONTENTS
1. Overview and Key Difference
2. What is Generalization in DBMS
3. What is Specialization in DBMS
4. Relationship Between Generalization and Specialization in DBMS
5. Side by Side Comparison – Generalization vs Specialization in DBMS in Tabular Form
6. Summary
What is Generalization in DBMS?
An entity refers to a real-world object, and there are relationships among the entities. The ER diagram is based on the Entity-relationship (ER) model. The Entity relationship model is model used to design and represent the relationships between data. In a Medical Center database, there can be an entity such as patient, doctor, staff member etc. Each entity has properties that describe them. They are known as attributes. The patient entity can have attributes such as patient_id, name, address, telephone etc. The association among entities is known as a relationship.
With the complexity of the data, the original ER model was developed further. It is known as Enhanced ER (EER) model. The diagram based on EER model is called the Enhanced ER (EER) diagram. Generalization is a concept which can be used when drawing the EER diagram. In Generalization, the lower entities can be combined into a higher-level entity. It is also known as bottom up approach. In this approach, the entities are combined together to perform a generalized entity.
Figure 01: Generalization, the bottom up approach
According to the above diagram, there are two entities called Student and Lecturer. The Student entity contains attributes student_id, name and city. The Lecturer contains attributes lecturer_id, name and city. Both can be combined together to create the Person entity. The name and city attributes are common to both entities. Therefore, they can be placed in Person entity. The Student entity has its own attribute student_id. The Lecturer entity has its own attribute lecturer_id. The entities Student and Lecturer are generalized further into Person entity.
What is Specialization in DBMS?
Specialization is the opposite of Generalization. In specialization, the higher-level entity can be broken down into lower level entities. The higher-level entity is specialized further. It is also known as top down approach. Consider, the same example as above.
Figure 02: Specialization, the top down approach
According to the above diagram, the entity Person can be further broken down into specialized entities which are Student and Lecturer. The Person entity has name and city entities. Therefore, those attributes also belong to Student and Lecturer entities. The Student entity contains the name and city attributes and its own attribute that is student_id. The Lecturer entity contains the name, city attributes and its own attribute which is lecturer_id. It can be observed that the Person entity is specialized further into Student and Lecturer.
What is the Relationship Between Generalization and Specialization in DBMS?
- Generalization is the opposite of Specialization and Specialization is the opposite of Generalization.
What is the Difference Between Generalization and Specialization in DBMS?
Generalization vs Specialization in DBMS |
|
| Generalization is the process of combining lower level entities to produce the higher-level entity. | Specialization is the process of dividing the higher-level entity into lower level entities. |
| Synonyms | |
| Generalization is known as bottom up approach. | Specialization is known as top down approach. |
| Main Task | |
| In Generalization, a number of entities are brought together into one generalized entity based on their similar characteristics. | In specialization, an entity is divided into sub-entities based on their characteristics. |
Summary – Generalization vs Specialization in DBMS
ER diagrams are used to model the structure of the database. It provides a conceptual understanding of the database. It is based on ER model. ER model was developed further, and it is known as the Enhanced ER model. The diagram based EER model is the EER model. Generalization and Specialization are two concepts that can be applied when drawing an Enhanced ER diagram. The difference between Generalization and Specialization in DBMS is that Generalization is the process of combining lower level entities to produce the higher-level entity while Specialization is the process of dividing the higher-level entity into lower level entities. This article discusses the difference between Generalization and Specialization in DBMS.
Reference:
1.“The Enhanced ER Model.” Generalization, Specialization and Aggregation in ER Model | Studytonight. Available here
2.“Generalization Aggregation.” Www.tutorialspoint.com, Tutorials Point, 8 Jan. 2018. Available here
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