Database Normalization: A Comprehensive Guide to Normal Forms, Study notes of Database Management Systems (DBMS)

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Normalization

What is Normalization?

• Normalization is a technique of organizing the data into multiple related tables to minimize DATA REDUNDANCY.

• What is Data Redundancy and why should we reduce it? • Repetition of data increase size of the database
• Other issues like:
• Insertion problem
• Deletion problem
• Updation problem

Types of Normal Forms

• First Normal Form (1NF)
• Second Normal Form (2NF)
• Third Normal Form (3NF)
• Boyce Codd Normal Form (BCNF)
• Fourth Normal Form (4NF)
• Fifth Normal Form (5NF) Advantages and Disadvantages
• Minimize data redundancy • Performance decreases when

Rule-

• Each column should contain atomic values.
• Entries like X,Y and W,X violates this rule.

Rule-

• A column should contain values that are of the same type
• Do not intermix different types of values in any column

Rule-

• Order in which data is saved doesn’t matter.
• Using SQL you can fetch data in any order.

Example 2NF

• It (relation) should be in 1NF

BCNF (Boyce-Codd Normal Form)

• Also known as 3.5 NF
• It must satisfy two conditions:
• It should be in 3NF
• For any dependency, AàB, A should be a superkey.

What IF?

NOW OUR TABLES SATISFY BCNF