Chapter 2, Level 3: Normalization & Relationships

Question 1

What is (database) normalisation?

Answer 1

Normalisation is the process of reducing duplication in database tables.

Question 2

What are the two Normal Form Rules?

Answer 2

1. Tables must not contain repeating groups of date in 1 column.
2. Tables must not contain redundant information i.e. repeating information.

Question 3

How are foreign keys important to joined tables?

Answer 3

Foreign keys reference primary keys from other tables.

Question 4

How do you meet the two Normalisation Rules?

Answer 4

Any information which is repeated should be placed in a new table. The existing and new tables could then be joined via their primary keys in another new table. This new table’s name by naming convention should be a combination of the two tables e.g. movies table and genres table joined, would be movies_genres.

Question 5

What are the three different types of table relationships?

Answer 5

One-to-One
One-to-Many
Many-to-Many