Home >> MySql >> What is Second Normal Form(2NF) in MySql

What is Second Normal Form(2NF) in MySql

A relation is said to be in 2NF iff-

1)-It is 1NF

2)-There should not be any partial dependency.

                             or

Non-prime attribute should be fully functional dependent on key.

                            or

Part of key should not derive any non prime attribute when key is composite.

Prime attribute-The attribute which forms key is called prime attribute and attribute which do not forms key is called non-prime attribute.

Example-

(A,B,C,D)  is a relation

AB

BC

is key then A,B,C is prime attribute and D is non-prime attribute.

Partial Dependency-

AB->CD

AB->C

AB->D

A->C
 

Post Your Comment

Next Questions
What is Third Normal Form(3NF)
What is Boyce Codd Normal Form(BCNF)
What is Fourth Normal Form(4NF)
What is Fifth Normal Form(5NF)
What is Index and why use indexing
What is clustered index
What is non clustered index
What is primary key index
What is unique key index
What is normal index
What is full text index
What are advantage and disadvantage of indexing
Create database
Drop database
Select database
Create table
Drop table
Truncate table
Insert query
Select table
Where clause
AND Clause
OR Clause
Update query
Delete query

Copyright ©2022 coderraj.com. All Rights Reserved.