1) DBMS Concepts

DBMS Tutorial Components of DBMS. Applications of DBMS The difference between file system and DBMS. Types of DBMS DBMS Architecture DBMS Schema Three Schema Architecture. DBMS Languages.

2) DBMS ER Model

ER model: Entity Relationship Diagram (ERD) Components of ER Model. DBMS Generalization, Specialization and Aggregation.

3) DBMS Relational Model

Codd’s rule of DBMS Relational DBMS concepts Relational Integrity Constraints DBMS keys Convert ER model into Relational model Difference between DBMS and RDBMS Relational Algebra DBMS Joins

4) DBMS Normalization

Functional Dependency Inference Rules Multivalued Dependency Normalization in DBMS: 1NF, 2NF, 3NF, BCNF and 4NF

5) DBMS Transaction

What is Transaction? States of transaction ACID Properties in DBMS Concurrent execution and its problems DBMS schedule DBMS Serializability Conflict Serializability View Serializability Deadlock in DBMS Concurrency control Protocols

6) Misc

Advantages of DBMS Disadvantages of DBMS Data Models in DBMS Relational Algebra in DBMS Cardinality in DBMS Entity in DBMS Attributes in DBMS Data Independence in DBMS Primary Key in DBMS Foreign Key in DBMS Candidate Key in DBMS Super Key in DBMS Aggregation in DBMS Hashing in DBMS Generalization in DBMS Specialization in DBMS View in DBMS File Organization in DBMS What Is A Cloud Database What Is A Database Levels Of Locking In DBMS What is RDBMS Fragmentation in Distributed DBMS What is Advanced Database Management System Data Abstraction in DBMS Checkpoint In DBMS B Tree in DBMS BCNF in DBMS Advantages of Threaded Binary Tree in DBMS Advantages of Database Management System in DBMS Enforcing Integrity Constraints in DBMS B-Tree Insertion in DBMS B+ Tree in DBMS Advantages of B-Tree in DBMS Types of Data Abstraction in DBMS Levels of Abstraction in DBMS 3- Tier Architecture in DBMS Anomalies in Database Management System Atomicity in Database Management System Characteristics of DBMS DBMS Examples Difference between Relational and Non-Relational Databases Domain Constraints in DBMS Entity and Entity set in DBMS ER Diagram for Banking System in DBMS ER Diagram for Company Database in DBMS ER Diagram for School Management System in DBMS ER Diagram for Student Management System in DBMS ER Diagram for University Database in DBMS ER Diagram of Company Database in DBMS Er Diagram Symbols and Notations in DBMS How to draw ER-Diagram in DBMS Integrity Constraints in DBMS Red-Black Tree Deletion in DBMS Red-Black Tree Properties in DBMS Red-Black Tree Visualization in DBMS Redundancy in Database Management System Secondary Key in DBMS Structure of DBMS 2-Tier Architecture in DBMS Advantages and Disadvantages of Binary Search Tree Closure of Functional Dependency in DBMS Consistency in Database Management System Durability in Database Management System ER Diagram for Bank Management System in DBMS ER Diagram for College Management System in DBMS ER Diagram for Hotel Management System in DBMS ER Diagram for Online Shopping ER Diagram for Railway Reservation System ER Diagram for Student Management System in DBMS Isolation in DBMS Lossless Join and Dependency Preserving Decomposition in DBMS Non-Key Attributes in DBMS

Generalization in DBMS

Generalization in DBMS

In the database management system, generalization is a concept combining the common attributes of two or more lower-level entity and form a new higher level with the common attributes. In this DBMS concept, we can also combine the generalized higher-level entity with the lower-level entities for creating a new higher-level entity.

This concept follows the bottom-up approach, which is just opposite to the specialization concept.  This concept is the same as the subclass and superclass, where more than one subclass combines to make a superclass.

Steps for Implementing the Generalization

If any user wants to implement the generalization concept for making the database simply, then we have to follow the following steps one by one:

Step 1: The first step for each user is to identify the two or more entities having common attributes of any database.

Step 2: After that, the user has to examine the common attributes of the identified entities.

Step 3: Now, the user has to define the new higher-level entity, which consists of the common attributes of identified lower-level entities. This new higher-level entity is termed a generalized entity.

Step 4: This is the last step. In this step, the user has to define the relationship between the generalized and lower-level entities.


Let us consider we have two entities in the School database, whose names are Student and Teacher. The attributes of the Student entity are Student_ID, Name, Age, Address, and mobile_no. Following ER-diagram shows the student entity with its four attributes.

The attributes of the Teacher entity are Teacher_ID, Name, Age, Address, Mobile_no. Following ER-diagram shows the Teacher entity with its four attributes.

These two entities of the School database have four common attributes, i.e., Name, Age, Mobile_no, and Address. So, both the specified entities are combined to form a new generalized entity of higher-level whose name is Person.

This new Person entity contains the four attributes Name, age, Mobile_no, and Address, which holds the values of all students and teachers of the school database.

As you can see in the ER diagram, which is given below, the same attributes (Name, Age, Mobile_no, and Address) of Student and Teacher are now connected with the Person entity, which is in relationship with both the entities.

Difference Between Generalization and Specialization

1. This concept of a database system works in a bottom-up manner.1. This concept of a database system works in a top-down manner.
2. In the generalization concept, schema size gets reduced.2. In the generalization concept, schema size gets increased.
3. This technique is applied to the multiple lower-level entities.3. This technique is applied to the single higher-level entity.
4. Inheritance process does not occur in this mechanism.4. Inheritance process occurs in this mechanism because the properties of the superclass are shared with the subclasses.
5. The higher-level entity in this technique must have lower-level entities.5. In this technique, the higher-level entity of the ER diagram may not have the entities of the lower level.
6. This mechanism takes the common features of multiple lower-level entities and forms a new higher entity.6. This mechanism splits the higher-level entity and form new entities with common properties.