Data Normalisation Basics

Page 1

What is data normalisation?

Is the process of organising the fields and tables of a relational database to minimize redundancy and dependency

First Normal Form (1NF)

For a database to be in first normal form (1NF), the following rules have to be met for each table in the database

There are no columns 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

Atomicity

'Atomic' is the word used to describe a data item that cannot be broken down any further.

Second Normal Form (2NF)

Requires that the data model is in 1NF already and that the data model leads to entities containing attributes that are dependent on the whole key identifier.

New Page