DBMS - Normalization | Normalization in RDBMS

Normalization is a technique of designing the database in structured way. It is the process of organizing the data in database. It was first proposed by E.F. Codd as an integral part of his relational model.

Normalization is a very essential part of relational model. It divides the larger table into the smaller table and links them using relationship.

Normalization is used to reduce data redundancy and improve data integrity. It is also used to eliminate the undesirable characteristics like Insertion, Update and Deletion Anomalies.

Normalizing our database ensures the following things:

• Dependencies between data are identified.
• Redundant data is minimized.

 · The data model is flexible and easier to maintain

Advantages of Normalization:

Normalization provides numerous benefits to a database. Some of the major advantages include the following:

• Greater overall database organization
• Reduces redundant data
• Provides data consistency within the database
• More flexible database design
• Higher database security
• Data modification anomalies are reduced.
• Data uniformity inside the database

Different Normalization Forms:

There are three most widely used normal forms: First normal form , Second normal form, and Third normal form. 

First Normal Forms:

A relation is in first normal form (1NF) if it contains only single (atomic) valued attributes/columns. If a relation contains composite or multi-valued attribute, it violates the first normal form.

The purpose of first normal form (1NF) is to eliminate repeating groups of attributes in an entity.

Second Normal Forms:

A relation will be in second normal form (2NF) if and only if it is in 1NF and relation must not contain any partial dependency. Partial Dependency occurs when a non-prime attribute is functionally dependent on part of a candidate key.

The purpose of 2NF is to eliminate partial key dependencies. In other words, each attribute in an entity must depend on the whole key, not just a part of it.

Third Normal Forms:

A relation will be in third normal form (3NF) if and only if it is in 2NF and it doesn’t have transition dependency. The elimination of transitive dependency from a 2NF relation leads to the relation in 3NF. No transitive dependency means non-prime attributes (which doesn’t form a candidate key) should not be dependent on other non-prime attributes.