Explain the concept of Normalization in DBMS?

It is the process of organizing the data in a database. It helps in removing the duplicate values in the database. Normalization divides the large table into smaller tables and links them using relationships.

The normal form is used to reduce redundancy from the database table. Normalization is the name given to the process of simplifying the relationship among data elements in a record.

In simple words we can say,

Normalization is the process of organizing data to minimize.

  • Redundancy/duplication/repetition.

  • Insertion, deletion, updating anomalies.

Normal forms

There are six Normal forms which are as follows −

  • First Normal Form (1NF)
  • Second Normal Form (2NF)
  • Third Normal Form (3NF)
  • Boyce-Codd Normal Form (BCNF)
  • Fourth Normal Form (4NF)
  • Fifth Normal Form (5NF)

These forms are explained in the figure given below −

Objective of Normalization

The main objectives of using normalization technique are as follows −

  • It provides a formal framework for analysing the relations based on the key attributes and their functional dependencies.

  • Freeing the relations from insertion, update and delete anomalies.

  • Reducing the need of re-structuring the tables.

While decomposing, the normalization process should ensure the following two properties are satisfied −

  • Lossless join or nonadditive property − It guarantees that the spurious tuples are not generated with respect to the relation schemas created after decomposition.

  • Dependency preservation property − It ensures that every functional dependency is represented in some of the individual relations resulting after decomposition.

  • Denormalization − It is the process of storing the join of higher normal form relations as a base relation- which is in a lower normal form.