Normalization of Database Tables

Question 1

What is normalization?

Answer 1

It is the evaluation and correction of table structures to minimize data redundancies

Question 2

What does normalization do?

Answer 2

It reduces data anomalies and assigns attributes to tables based on determination

Question 3

What are the three different normal forms?

Answer 3

First normal form
Second normal form
Third normal form

Question 4

What is the structural point of view of normal forms?

Answer 4

Higher normal forms are better than lower normal forms
Properly designed 3NF structures meet the requirement of fourth normal form (4NF)

Question 5

What is denormalization?

Answer 5

It is when there is the production of a lower normal form

Question 6

What does denormalization result in?

Answer 6

It results in an increased performance and greater data redundancy

Question 7

What does normalization do when used while designing a new database structure?

Answer 7

Analyzes the relationship among the attributes within each entity
Determines if the structure can be improved through normalization
Improves the existing data structure and creates an appropriate database design

Question 8

What is unnormalized data?

Answer 8

It is raw data in its original state, it might contain redundant data, multivalued data, and/or other data anomalies not found on normalized data relations

Question 9

What is the objective of the normalization process?

Answer 9

It is to ensure that each table conforms to the concept of well-formed relations
That all tables are at least 3NF

Question 10

What are the well-formed relations that normalization attempts to make each table conform to?

Answer 10

Each table represents a single subject
Each row/column intersection contains only one value and not a group of values
No data item will be unnecessarily stored in more than one table
All nonprime attributes in a table are dependent on the primary key
Each table has no insertion, update, or deletion anomalies

Question 11

What is functional dependence?

Answer 11

It is when one attribute is fully functionally dependent on another attribute if each value of the other attribute determines one and only one value of the initial (one) attribute

Question 12

What is fully functional dependence?

Answer 12

It is when an attribute is functionally dependent on a composite key of another attribute but not on any subset of that composite key, the initial attribute is fully functionally dependent on the other attribute

Question 13

What is a partial dependency?

Answer 13

It is a functional dependency in which the determinant is only part of the primary key

Question 14

What is a transitive dependency?

Answer 14

It is when an attribute is dependent on another attribute that is not part of the primary key

Question 15

What is a repeating group?

Answer 15

It is when a group of multiple entries of the same type can exist for any single key attribute occurence

Question 16

What is the three step procedure of converting to the first normal form?

Answer 16

Eliminate the repeating groups
Identify the primary key
Identify all dependencies

Question 17

What is the dependency diagram?

Answer 17

It is a diagram that depicts all dependencies found within a given table structure

Question 18

What does 1NF describe?

Answer 18

It describes the tabular format in which all key attributes are defined, there are no repeating groups in the table, all attributes are dependent on the primary key

Question 19

When does conversion to 2NF occur?

Answer 19

It occurs when the 1NF has a composite primary key