Normalization is scientific method of breaking down complex table structures into simple table structures by using certain rules. Using this method, you can, reduce redundancy in a table and eliminate the problems of inconsistency and disk space usage. You can also ensure that there is no lose of information.
Normalization has several benefits. It enables faster sorting and index creation, more clustered indexes, few indexes per table, few NULLs, and makes the database compact. Normalization helps to simplify the structure of tables. The performance of an application is directly linked to the database design. A poor design hinders the performance of the system. The logical design of the database lays the foundation for an optimal database.
Some rules that should be followed to achieve a good database design are :
- Each table should have an identifier
- Each table should store data for a single type of entity
- Columns that accept NULLs should be avoided
- The repetition of values or columns should be avoided.
Normalization results in the formation of tables that satisfy certain specified rules and represent certain normal forms. The normal forms are used to ensure that various types of anomalies and inconsistencies are not introduced in the database. A table structure is always in a certain normal form. Several normal forms have been identified. The most important and widely used normal forms are :
- First Normal Form (1NF)
- Second Normal Form (2NF)
- Third Normal Form (3NF)
- Boycee- Codd Normal Form (BCNF)
The first, second and third normal forms were originally defined by Dr. E.F Codd. Later, Boycee and Codd, introduced another normal form called the Boycee-Codd Normal Form.