Relational Database Concepts

Question 1

What is 2nd normal form?

Answer 1

“Any non-key field should be dependent on the entire primary key”

This concept comes into play when using a composite primary key. For example, with composite primary key made up of course number and start date. If you had another field for course name, this would be dependent on course number only and would violate 2nd form.

Question 2

What is 3rd normal form?

Answer 2

“No non-key field is dependent on another non-key field”

In other words, can I figure out any of the values in this row from any of the other values in this row? For example, room and capacity. If these two fields are in a table where neither are the primary key, this is a duplication of information and violates 3rd form.

Question 3

What is 1st normal form?

Answer 3

“No repeating values and no repeating groups”