Normalization

The biggest problem needed to be solved in database is data redundancy.

Why data redundancy is the problem? Because it causes:

Insert Anomaly

Update Anomaly

Delete Anomaly

Normalization is the process of removing redundant data from your tables to

improve storage efficiency, data integrity, and scalability.

Normalization generally involves splitting existing tables into multiple ones,

which must be re-joined or linked each time a query is issued.

Why normalization?

The relation derived from the user view or data store will most likely be

unnormalized.

The problem usually happens when an existing system uses unstructured

file, e.g. in MS Excel.

Steps of Normalization First Normal Form (1NF)

Second Normal Form (2NF)

Third Normal Form (3NF)

Boyce-Codd Normal Form (BCNF)

Fourth Normal Form (4NF)

Fifth Normal Form (5NF)

In practice, 1NF, 2NF, and 3NF are enough for database

SCENERIO HERE WE ARE GOING TO DESCRIBE THE PATIENT DATA BASE,IT WILL ILLUSTRATE THE RELATION

SHIPS,DEPENDECIES AND COMPLEXITY OF UN NORMALIZED FORMS.

ONLY TABLE OF A SINGLE PATIENT WITH ATTRIBUTES IS SHOWN HERE FOR THE SAKE OF UNDERSTANDING.

First Normal Form (1NF) The official qualifications for 1NF are:

1. Each attribute name must be unique.

2. Each attribute value must be single.

3. Each row must be unique.

4. There is no repeating groups.

Additional:

Choose a primary key.

Reminder:

A primary key is unique, not null, unchanged. A primary key can be either

an attribute or combined attributes.

EXAMPLE

It violates the 1NF because:

Attribute values are not single.

Repeating groups exists.

NF-1 TABLE GIVEN BELOW

ID Name Gender Department Disease Zip City State Street Age D.O Admission D.O.Discharge

1321 Saeed-ur-Rasheed Male Pathology Kidney 64200 R.Y.K Pakistan 1 23 8/12/2014 12/12/2018

1321 Saeed-ur-Rasheed Male Pathology Stomach 64200 R.Y.K Pakistan 1 23 8/12/2014 12/12/2018

1308 Ali Raza Male Emergency Scratches 64200 R.Y.K Pakistan 14 20 8/12/2016 10/12/2016

1333 M.Yousaf Male Emergency Wounds 64200 R.Y.K Pakistan 233 18 8/12/2014 10/12/2014

1319 Salman Majeed Male Aansoo Lake I think Fracture ha 64200 R.Y.K Pakistan 123 28 4/8/2016 4/8/2025

1319 Salman Majeed Male Aansoo Lake Laat toot gai 64200 R.Y.K Pakistan 123 28 4/8/2016 4/8/2025

ID Name Gender Department Disease Zip City State Street Age D.O

Admission D.O.Discharge

1321 Saeed-ur-Rasheed Male Pathology Kidney,Stomach 64200 R.Y.K Pakistan 1 23 8/12/2014 12/12/2018

1308 Ali Raza Male Emergency Scratches 64200 R.Y.K Pakistan 14 20 8/12/2016 10/12/2016

1333 M.Yousaf Male Emergency Wounds 64200 R.Y.K Pakistan 233 18 8/12/2014 10/12/2014

1319 Salman Majeed Male Aansoo Lake I think Fracture ha,Laat toot gai 64200 R.Y.K Pakistan 123 28 4/8/2016 4/8/2025

The official qualifications for 2NF are:

1. A table is already in 1NF.

2. All non-key attributes are fully dependent on the primary key.

All partial dependencies are removed to place in another table.

Second Normal Form (2NF)

ID Name Gender Department Disease Zip City State Street D.O

Admission D.O.Discharge

1321 Saeed-ur-Rasheed Male Pathology Kidney 64200 R.Y.K Pakistan 1 8/12/2014 12/12/2018

1321 Saeed-ur-Rasheed Male Pathology Stomach 64200 R.Y.K Pakistan 1 8/12/2014 12/12/2018

1308 Ali Raza Male Emergency Scratches 64200 R.Y.K Pakistan 14 8/12/2016 10/12/2016

1333 M.Yousaf Male Emergency Wounds 64200 R.Y.K Pakistan 233 8/12/2014 10/12/2014

1319 Salman Majeed Male Aansoo Lake I think Fracture ha 64200 R.Y.K Pakistan 123 4/8/2016 4/8/2025

1319 Salman Majeed Male Aansoo Lake Laat toot gai 64200 R.Y.K Pakistan 123 4/8/2016 4/8/2025

AGE TABLE

Name Age

Saeed-ur-Rasheed 23

Ali Raza 20

M.Yousaf 18

Salman Majeed 28

The official qualifications for 3NF are:

1. A table is already in 2NF.

2. Nonprimary key attributes do not depend on other nonprimary key

attributes (i.e. no transitive dependencies)

All transitive dependencies are removed to place in another table.

Third Normal Form (3NF)

ID Name Gender Departement Disease Zip City State Street D.O

Admission D.O.Discharge

1321 Saeed-ur-Rasheed Male Pathology Kidney 64200 R.Y.K Pakistan 1 8/12/2014 12/12/2018

1321 Saeed-ur-Rasheed Male Pathology Stomach 64200 R.Y.K Pakistan 1 8/12/2014 12/12/2018

1308 Ali Raza Male Emergency Scratches 64200 R.Y.K Pakistan 14 8/12/2016 10/12/2016

1333 M.Yousaf Male Emergency Wounds 64200 R.Y.K Pakistan 233 8/12/2014 10/12/2014

1319 Salman Majeed Male Aansoo Lake I think Fracture ha 64200 R.Y.K Pakistan 123 4/8/2016 4/8/2025

1319 Salman Majeed Male Aansoo Lake Laat toot gai 64200 R.Y.K Pakistan 123 4/8/2016 4/8/2025

AGE TABLE

Name Age

Saeed-ur-Rasheed 23

Ali Raza 20

M.Yousaf 18

Salman Majeed 28

DISEASE TABLE

ID Departement Disease

1321 Pathology Kidney

1321 Pathology Stomach

1308 Emergency Scratches

1333 Emergency Wounds

1319 Aansoo Lake I think Fracture ha

1319 Aansoo Lake Laat toot gai

ADDRESS TABLE

ID Zip City State Street

1321 64200 R.Y.K Pakistan 1

1308 64200 R.Y.K Pakistan 14

1333 64200 R.Y.K Pakistan 233

1319 64200 R.Y.K Pakistan 123

FINALIZED 3NF TABLE

ID Name Gender Zip

1321 Saeed-ur-Rasheed Male 64200

1308 Ali Raza Male 64200

1333 M.Yousaf Male 64200

1319 Salman Majeed Male 64200