This is an unusual question for an application developer. Read about it on Google. Database normalization is the process of storing data in tables in the most efficient manner possible. Database normalization is broken down into normal data forms (abbreviated NF), and there are levels - 1NF, 2NF, 3NF, 4NF, 5NF, 6NF and BCNF (Boyce-Codd Normal Form). Learn what 1 - 3 NF are, and realize that most practical database are normalized at 3NF. Remember: The Key (1NF), The Whole Key (2NF), and Nothing But The Key (3NF), so help me Codd. If you don't know what that phrase means, you should look it up on Google so you can demonstrate that you understand primary keys, table design, and normalization. I have found that you can often recite that welll-known phrase in an IT interview to communicate to the interviewer that you know your stuff!