Specialization in DBMS

Specialization in DBMS


In this article, we will learn about Specialization in DBMS.

The main purpose of specialization is to define subsets of entities that have few distinguishing features or attributes

  • Definition: Specialisation is a top-down design approach where one higher level entity can be broken into two or more lower level entities so that subsets of entities that share some distinguishing characteristics can be identified
  • The specialization can be viewed as a reverse design process for generalization

Example: All types of employees in a company how common requirements or functionalities like name salary  etc

The specialization is always done on a single entity over design it increases the schema size

Specialization in DBMS

Design steps for Specialisation

  • Generally, superclasses are defined first
  • Define subclass and its related attributes
  • IS-A Relationship is linked between these entities

Example for Specialisation

  • Consider an entity employee which consists of attributes name and salary, all types of employees like  technician, engineer, accountant [ sub entities]  have different roles in the company, but all employees working in a company have some common functionalities or requirements like salary, id iD, name, etc i.e these properties are common  to all the employees
  • Identified common properties are inherited from parent entity (employee) to submit entities(tester, accountant, engineer)


  • The main Idea behind specialization is the sharing of common properties between entities
  • Specialisation is a top-down design process

Generalization V/S Specialisation

Both generalization specialization are design procedures and are equally important in designing a schema
Let’s understand the key differences between the two



  • Purpose: Generalisation identify the common among multiple entities landforms new entities
  • Design approach: proceeds in a bottom-up approach
  • Size of schema: Generalization reduces the size of Schema
  • Application: It is applied to a group of entities
  • Entities: Higher level entity must have a low-level entity


  • Purpose: Specialisation splits an entity to form multiple entities so that some features can be inherited from the split entity
  • Design procedure: Proceeds in a top-down approach
  • Size of Schema: It increases the size of Schema
  • Application: It Is applied to a single entity
  • Entities: The higher level entity may or may not have low-level entities
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