Normal Form

Question 1

What is Normalisation

Answer 1

Normalisation is the process of coming up with the best possible layout for a relational database.

Question 2

What is First Normal Form

Answer 2

• All fields names must be unique
• Values in fields should be from the same domain
• Values in fields should be atomic
• No two records may be identical
• Every table must have a primary key

Atomic = each field having only one item of data

Question 3

Second Normal Form

Answer 3

• The data must already be in 1NF
• Remove any partial dependencies
• Fix any M:M relationship created as a result

Question 4

Third Normal Form

Answer 4

If the database is in second normal form and contain no non-key dependencies, it is in third normal form. Meaning the attributes only depends on the value of the primary key and nothing else.

Question 4

Third Normal Form

Answer 4

• The data must already be in 2NF
• Remove any transitive dependcies (In other words, ensure that non-key fields are not dependent on each other.