About

The process of database normalisation is the process of organising data in a database, such that the database maintains integrity and reduce data redundancy. There are five phases of database normalisation.

1NF

  1. Row Order should not matter in a relational database. Say we have the height of individuals, and the order of their height from smallest to largest is Bob, Charles, Max.

Incorrect

ID Name
1 Bob
2 Charles
3 Max

Correct

ID Name Height Order
1 Bob 1
2 Charles 2
3 Max 3
  1. Shouldn’t mix data types per column
  2. Each Table should have a primary key to distinctly identify each row
  3. Tables shouldn’t have repeating groups

Repeating Group Example

Player_ID Inventory
hi [2 apples, one pen]
bye [one stone, two cereal, three phones]

Shouldn’t be shown like this

Player_ID Inventory Item 1 Inventory Item 2 Inventory Item 3
hi 2 apples pen
bye one stone two cereal three phones

Rather should be

Player_ID Inventory
hi 2 apples
hi pen
bye one stone
bye two cereal
bye three phones

2NF