Database Normalization

Normalization is the process of organizing data in a database to minimize redundancy and eliminate undesirable characteristics like insertion, update, and deletion anomalies.

Normalization is the process of organizing data in a database to minimize redundancy and eliminate undesirable characteristics like insertion, update, and deletion anomalies.

Normalization helps in:

• Breaks table into smaller, related tables.
• Eliminates insert, update, delete anomalies.
• Make data consistent, reliable, and scalable.

1. First Normal Forms (1NF)

• Using row order to convey the information is not permitted
• Mixing the datatypes within the same columns is not permitted
• Having a table without primary key is not permitted
• Repeating the item or groups within same row is not permitted

Before 1NF Player Inventory

Improved 1NF Player Inventory

🔑 Primary key → player_id ****+ item_type

2. Second Normal Forms (2NF):

Every non-key attribute in the table should depend on the entire primary key (applies when composite key exists)

Before 2NF Player Inventory

Improved 1NF Player Inventory

Player

Player Inventory

3. Third Normal Forms (3NF):

Every non-key attribute in the table should depend on the key, the whole key or nothing but a key. Remove transitive dependency

Before 3NF Player

Dependency Flow

Player_Id → Player_Skill_Level Player_Id → Player_Skill_Level → Player_Rating Transitive Dependency

Improved 3NF

Player

Player_Skill_Level

4. Fourth Normal Forms (4NF):

Multivalued dependencies in a table must be multivalued dependencies on the key

Before 4NF Model_Colors_And_Styles_Available

Improved 4NF

Model_Colors_Available

Model_Styles_Available

5. Third Normal Forms (5NF):

5NF removes redundancy caused by complex join dependencies. A table should be split into smaller tables if it can be perfectly reconstructed by joining them together.