Database normalization

FIRST NORMAL FORM
NO repeating columns containing same type of data
ALL columns contain a single value
Unique PRIMARY KEY for each row

SECOND NORMAL FORM
Table must be in First Normal Form
Create new tables for any data that is repeated in columns
Each new table needs a unique PRIMARY KEY for each row.

AUTO_INCREMENT

can do this.

THIRD NORMAL FORM
Table must be in First and Second Normal Form. This is usually all that is necessary.
Any data that is not dependent on a primary key, but is dependent on another value, should be removed to another table. This is a very strict use of normalization.