What is Normalization? Its Purpose and steps in normalization process

Normalization is the process of organizing data in a database. This includes creating tables and establishing relationships between those tables according to rules designed both to protect the data and to make the database more flexible by eliminating two factors: redundancy and inconsistent dependency.

Redundant data wastes disk space and creates maintenance problems.

Normalization is the analysis of functional dependencies between attributes.

It is the process of decomposing relations with anomalies to produce well-structured relations.

Normalization is a formal process for deciding which attributes should be grouped together in a relation. It is the primary tool to validate and improve a logical design so that it satisfies certain constraints that avoid unnecessary duplication of data.

Purpose of Normalization

Normalization allows us to minimize insert, update, and delete anomalies and help maintain data consistency in the database.

1. To avoid redundancy by storing each fact within the database only once
   
2. To put data into the form that is more able to accurately accommodate change
   
3. To avoid certain updating “anomalies”
   
4. To facilitate the enforcement of data constraint
   
5. To avoid unnecessary coding. Extra programming in triggers, stored procedures can be required to handle the non-normalized data and this in turn can impair performance significantly.

Steps in Normalization

The degree of normalization is defined by normal forms. The normal forms in an increasing level of normalization, are first normal form (1NF), second normal form (2NF), 3NF, Boyce-Codd Normal form,4NF and 5NF.

Each normal form is a set of conditions on a schema that guarantees certain properties relating to redundancy and update anomalies.

In general 3NF is considered good enough. In certain instances, a lower level of normalization, that is the instance where queries take enormous time to execute.