What is the Difference Between Generalization and Specialization in DBMS?

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Generalization and specialization are two processes in Database Management Systems (DBMS) that help in structuring and organizing data. They are often considered mirror images of each other, but they have distinct differences:

Generalization:

  1. Works on a bottom-up approach.
  2. Reduces the size of the schema.
  3. Can be applied to a group of entities.
  4. Focuses on the common features of entities, leading to the creation of a higher entity.

Specialization:

  1. Works on a top-down approach.
  2. Increases the size of the schema.
  3. Can only be applied to a single entity.
  4. Involves splitting a higher entity to create lower entities, highlighting the differences between these lower entities.

In summary, generalization combines lower-level entities to form a higher-level entity, focusing on their similarities. On the other hand, specialization splits a higher-level entity into lower-level entities, emphasizing their differences.

Comparative Table: Generalization vs Specialization in DBMS

Here is a table highlighting the differences between generalization and specialization in Database Management Systems (DBMS):

Feature Generalization Specialization
Approach Bottom-up Top-down
Schema Size Reduced Increased
Entity Sets Multiple Single
Inheritance Not used May be used
  • Generalization works on the principle of a bottom-up approach, where lower-level functions are combined to form higher-level functions, reducing the size of the schema. It can be applied to multiple entities and does not use inheritance.

  • Specialization works on the principle of a top-down approach, where a higher-level entity is split into lower-level entities, increasing the size of the schema. It can only be applied to a single entity and may use inheritance.

In summary, generalization involves creating a more general entity by combining multiple lower-level entities, while specialization involves creating subtypes from a general entity type.