Description of normalization

Normalization:

• The process of organizing data in a database.
• Creating tables and establishing relationships between those tables according to rules designed both to protect the data
• Make the database more flexible by eliminating redundancy and inconsistent dependency.
• Redundant data -> wastes disk space and creates maintenance problems.
• Problem of redundancy : If data that exists in more than one place must be changed, the data must be changed in exactly the same way in all locations.
• Inconsistency Dependancy: can make data difficult to access because the path to find the data may be missing or broken.

Rules of Normalization

1NF

1. Eliminate repeating groups in individual tables.
2. Create a separate table for each set of related data.
3. Identify each set of related data with a primary key.

   2NF

4. Create separate tables for sets of values that apply to multiple records.
5. Relate these tables with a foreign key.

   3NF

6. Eliminate fields that do not depend on the key.

Normazlization Example