Basic Concept of Database Normalization

“Normalization” one of the most common word related to data base. In fact this is a interesting topics in Relational database systems. Let me explain this using some new examples….

“NORMALIZATION IS A PROCESS BY WHICH WE LOOK FORWARD OVER TWO FACTS : 1. REDUNDANT DATA ELIMINATION. 2.DATA DEPENDENCIES WILL MAKE SENSE. WHICH HELPS TO REDUCES THE DATABASE SPACE CONSUMPTION.”

Their are some series of guidelines are developed by the communities of database, known as first, second, third and fourth some how fifth normalization forms. But i am going to discuss only three of them :

1. First Normal Form :
Their are only two root rules
1.1 Their should be no duplicate columns.
1.2 For each group of related data their should be separate tables, in which identify each row uniquely by a column or set of column.
Example : This is EmployeeMaster as

Emp Code	Emp Name	Emp City One	Emp City Two	Basic Salary	Var Salary	Total Salary
EMP001	Neeraj Tripathi	Delhi	Gurgaun	10000	5000	15000
EMP002	Mayank Nath	Mumbai	Pune	15000	8500	23500

So apply the first normal form, Emp City will come in one column and Emp Name will break in two fiels:

Emp Code	Emp First Name	Emp Last Name	Emp City	Basic Salary	Var Salary	Total Salary
EMP001	Neeraj	Tripathi	Delhi	10000	5000	15000
EMP001	Neeraj	Tripathi	Gurgaun	10000	5000	15000
EMP002	Mayank	Nath	Mumbai	15000	8500	23500
EMP002	Mayank	Nath	Pune	15000	8500	23500

Now the given record set is in the first normal form.

2. Second Normal Form :
This form state that after fulfilling all the condition of first normal form, their are two more conditions
2.1 Place those data in separate tables which are not directly related to the primary key of that table.
2.2 Create relationship between these tables using new table key (Foreign Key).

Emp Code	Emp First Name	Emp Last Name	Emp City Id	Basic Salary	Var Salary	Total Salary
EMP001	Neeraj	Tripathi	1	10000	5000	15000
EMP001	Neeraj	Tripathi	2	10000	5000	15000
EMP002	Mayank	Nath	3	15000	8500	23500
EMP002	Mayank	Nath	4	15000	8500	23500

And City Master become in scene

City Id	City Name
1	Delhi
2	Gurgaun
3	Pune
4	Mumbai

That is now takes our database to a second normal form.

3. Third Normal Form :

So now meet all the fundamentals for IInd normal form and then

3.1 Remove all the non key fields which are depend on other non key fields.
In our table “Total Salary” is a kind of field. So :

Emp Code	Emp First Name	Emp Last Name	Emp City Id	Basic Salary	Var Salary
EMP001	Neeraj	Tripathi	1	10000	5000
EMP001	Neeraj	Tripathi	2	10000	5000
EMP002	Mayank	Nath	3	15000	8500
EMP002	Mayank	Nath	4	15000	8500

So the “Total Salary” field is removed which can be easily get by “Basic Salary” + “Var Salary”.
Ok Now our Database is normalized at the stage of Third normal form.

These are most applicable normal forms of database. I am not giving the idea about fourth and fifth normal forms. I apologies for that. But they have been rarely used in database normalization.

Now Happy reading. Cheers.
Neeraj Tripathi