Database Normalization

Database normalization is the process of structuring a database, usually a relational database, in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity.

• Flexible Database Design
• Reduce Data redundancy
• Improves the data integrity
• Makes an organized Database

Normalization Types

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

First Normal Form (1NF)

For a table to be in the first Normal Form:

• It should not have repeating values in a group.
• It should not have repeating groups.

Second Normal Form (2NF)

For a table to be in the second Normal Form:

• Should be in 1NF.
• Any non-key field should entirely depend on its primary key.
• No partial dependency (Occurs when there is a composite key).

Third Normal Form (3NF)

• Should be in 2NF.
• Any non-key field must not depend on other non-key fields.
• No transitive dependency.

What is a KEY?

A KEY is a value used to identify a record in a table uniquely. It could be a single column or a combination of multiple columns.

Primary Key: A single column value used to identify a database record uniquely.
Composite Key: A primary key composed of multiple columns.
Transitive Dependency: Occurs when one non-prime column is dependent on another non-prime column.

The Risks of Non-Normalized Data

• Update Anomaly: Data inconsistency resulting from redundancy and a partial update.
• Insert Anomaly: Inability to add data due to the absence of other required data.
• Delete Anomaly: Unintended loss of data due to deletion of other records.