Normalisation

Question 1

What is a composite key?

Answer 1

A key table linking a many-to-many relationship table.

Question 2

How to make a database in first normal form?

Answer 2

Each record is unique.
Each field has a unique name.
Data must be atomic.
No repeated or similar data.

Question 3

What does it mean for data to be atomic?

Answer 3

Data is distinct and can’t be broken down any further.

Question 4

How to make a database in second normal form?

Answer 4

Non-key fields must depend on every part of the primary key.
If you don’t have any composite primary keys, 2NF isn’t required.

Question 5

How to make a database in third normal form?

Answer 5

There are no non-key fields that depend on another non-key field.
If you can find a key that isn’t the primary key which depends on another field that isn’t the primary key then it’s not in 3rd form.
All fields must depend on the key, the whole key and nothing but the key.