Normalization

Introduction

• It is a database design technique to divides larger tables into smaller tables and links them using relationships.

• Used to reduces data redundancy and eliminates undesirable characteristics like Insertion, Update and Deletion Anomalies. Normalization rules divides larger tables into smaller tables and links them using relationships.

Original Form

1st Normal Form

• Add a unique column (Primary Key)to make each row becomes unique

2nd Normal Form

• All the non-key column must depend on the key

• Since the key is related to the personal information, and the supplier, price, item are not related, so we separate them out

3rd Normal Form

• Except the unique key, other non-key column should not be related with each others

• Since Supplier phone depends on supplier, so we separate them out

4th Normal Form

• No repeated primary key

• since a customer id contains multiple newsletter, so we separate it out