One of the most important factors in dynamic web page development is database definition. If your tables are not set up properly, it can cause you a lot of headaches down the road when you have to perform miraculous SQL calls in your code in order to extract the data you want. By understanding data relationships and the normalization of data, you will be better prepared to begin developing your application.

Basically, the Rules of Normalization are enforced by eliminating redundancy and inconsistent dependency in your table designs. I will explain what that means by examining the five progressive steps to normalization you should be aware of in order to create a functional and efficient database. I’ll also detail the types of relationships your data structure can utilize.

Types of Normal Forms

Normalization works through a series of stages called Normal forms. The normal forms apply to individual relations. The relation is said to be in particular normal form if it satisfies constraints.

Normal Form	Description
1NF	A relation is in 1NF if it contains an atomic value.
2NF	A relation will be in 2NF if it is in 1NF and all non-key attributes are fully functional dependent on the primary key.
3NF	A relation will be in 3NF if it is in 2NF and no transition dependency exists.
BCNF	A stronger definition of 3NF is known as Boyce Codd's normal form.
4NF	A relation will be in 4NF if it is in Boyce Codd's normal form and has no multi-valued dependency.
5NF	A relation is in 5NF. If it is in 4NF and does not contain any join dependency, joining should be lossless.