Topic 8: Normalization

Question 1

What is Normalization

Answer 1

It is the process that involves the elimination of inappropriate functional dependencies in a relation

In simpler terms it is the reorganization of a database in order to reduce redundancy

Question 2

What is the purposes of Normalization?

Answer 2

The main purpose of Normalization is to reduce redundancy and eliminate complexity

Question 3

What is a repeating group?

Answer 3

It is an attribute or group of attributes that occurs with multiple variables in a single instance of a primary key

Question 4

What is UNF

Answer 4

It is the state prior to the 1st Normal Form wherein the relation still containsone or more repeating groups

Question 5

When is a relation in the first normal form?

Answer 5

It is when in the intersection of a row and column in a relation has only one and only one value

Question 6

How to transform UNF to 1NF

Answer 6

Idenitify the repeating groups within the table and remove them

Question 7

Limitations of 1NF

Answer 7

1NF only removes repeating groups, but not redundancy

Question 8

When is a relation in the 2NF

Answer 8

• It is already in 1NF
• primary key consists of only one attribute
• no non-key attributes exists in the relation
• every non-key attribute is functionally dependent on the full-set of primary keys

Question 9

What is full functional dependency?

Answer 9

in a relatonship where X -> Y, Y is functionally dependent to X if X determines the value of Y. If we know the value of X then we will know the value of Y

Question 10

When is a relation in the 3NF

Answer 10

• It is in the 2NF
• no transitive dependencies