2. Normal Forms

Over time some good rules have been developed that allows a database to be designed with different levels of efficiency. These sets of rules are called the 'Normal Forms' and are numbered from 0 to 5. So there is a first, second, third, fourth and fifth normal form.

The short hand for these are 0NF, 1NF, 2NF, 3NF, 4NF, 5NF

You do not need to be concerned with the fourth and fifth normal forms as these are not required on this syllabus. We will only discuss first, second and third normal forms.

You should be aware that normal forms are only guidelines for the database designer - they do not have to follow them!

The designer will choose the form needed depending on what kind of database is to be developed. They may decide not to normalise his database at all, in which case it is called an 'unnormalised database' or 0NF.