Characteristics of 1st, 2nd & 3rd Normalisation Forms

Characteristics of 1st, 2nd & 3rd Normalisation Forms

1. 1st Normalisation

   • Rules of 1st Normalisation Form
     • There are no coloumns with repeated or similar data
     • Each data item cannot be broken down any further
     • Each row is unique i.e. it has a primary key
     • Each Field has an unique name
   • Atomic Data
     • Atomic is the word used to describe a data item that cannot be broken down any further
       • Example: Identity number, national insurance number

2. 2nd Normalisation Form

   • Rules of 2nd Normalisation Form
     • Non key attributes must depend on every part of their primary key
     • The table must already be in 1st normalisation form

3. 3rd Normalisation Form

   • Rules of 3rd Normalisation Form
     • Normalisation can only be done if the following rules have been met.
     • If it is already in 2nd normal form
     • There are no non-key attributes that depend on another non-key attribute