First Normal Form 1NF in Database Management System

First normal form in dbms

To remove the retundency from our database we always use normalization. So our database remain less retundent.

There are total 6 normal forms we study in database management system, but we mainly focus on first four.

• 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

So in this article we will loo at what is First Normal Form

First Normal Form (1NF)

A relation is said to be in first normal form if it does not have any multi-valued columns in other words a column of a table cannot hold multiple values. It must hold only single-valued attribute.

Example: Here we have a table and we can see what is wrong with this table. In this table employee details are saved. 

EMPLOYEE table:

EMP_ID	EMP_NAME	EMP_MOBILE	EMP_TYPE
1	Akash	42726388, 20621438	FTE
2	Anuj	85300303	Trainee
3	Vivek	13080389, 12830302	PTE

So we can see that in this table mobile number column has multiple values that is it violates the condition of first normal form. We have to solve this issue to make our relation in first normal  form. So we will decompose that column of EMPLOYEE table and convert into 1NF has been shown below:

EMP_ID	EMP_NAME	EMP_MOBILE	EMP_TYPE
1	Akash	42726388	FTE
1	Akash	20621438	FTE
2	Anuj	85300303	Trainee
3	Vivek	13080389	PTE
3	Vivek	12830302	PTE

So now our relation is in first normal form. 

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