Normalization

Question 1

1NF

Answer 1

Atomic and single-valued columns (values in cells must not be tables).
No composite or multi-valued attribute types.

Question 2

Relational Database Prerequisite

Answer 2

Each row must have a primary key, which uniquely identifies each row.

Question 3

2NF

Answer 3

Satisfies 1NF and no partial functional dependencies of non-prime attributes on candidate keys

Question 4

Why Normalize (What is the goal)

Answer 4

1. Minimize update, insertion, and deletion anomalies.

2. Minimize redesign when extending Database structure.

Question 5

To get to 1NF

Answer 5

For any column with multi-valued or composite values, create a second table with a Foreign key to the Primary key of the original table and the values as single rows in the new table.

Question 6

To get to 2NF

Answer 6

Set up a new relation for each partial key together with its dependent attribute types. Keep a relation with the original table through a primary key

Question 7

3NF

Answer 7

Satisfies 2NF and no non-prime attribute type is transitively dependent on the primary key.

Question 8

To get to 3NF

Answer 8

Set up a new relation that includes the non-key attribute types that functionally determine the other non-key attribute types.

Question 9

BCNF (Boyce-Codd)

Answer 9

3NF and for each of its non-trivial functional dependencies X->Y, X is a superkey. X is either a candidate key or a superset thereof.

Question 10

4NF

Answer 10

Every non-trivial multi-valued dependency begins with a superkey

Question 11

What is Denormalization

Answer 11

Denormalization refers to a technique which is used to access data from higher to lower forms of a database. It helps the database managers to increase the performance of the entire infrastructure as it introduces redundancy into a table. It adds the redundant data into a table by incorporating database queries that combine data from various tables into a single table.