Home Sql Databaseconcepts Second Normal Form (2NF)
Questions:Ask|Latest


 
 

Share on Google+Share on Google+

Second Normal Form (2NF)

Advertisement
The concept of remove the delicacy of data comes in the Second Normal Form (2NF).

Second Normal Form (2NF)

     

Second Normal Form (2NF)

The concept of remove the delicacy of data comes in the Second Normal Form (2NF).

A.  It should meet all the requirements of the first normal form.
B.  It should remove subsets of data that apply to multiple rows of a table and place them in separate tables. 
C.  It create relationships between these new tables and their predecessors through the use of foreign keys. 

The First Normal form deals with the atomicity whereas the Second Normal Form deals with the relationship between the composite key columns and non-key columns. To achieve the next progressive level your table should satisfy the requirement of First Normal Form then move towards the Second Normal Form.

Let's introduce a Review table as an example :

Item Colors Price Tax
Pen red 2.0 0.20
Pen blue 2.0 0.20
Scale red 2.0 0.20
Scale yellow 2.0 0.20
Bag blue 150.00 7.80
Bag black 150.00 7.80

Table is not in Second Normal Form because the price and tax depends on the item, but not color.

Item Colors
Pen red
Pen blue
Scale red
Scale yellow
Bag blue
Bag black

 

Item Price Tax
Pen 2.0 0.20
Scale 2.0 0.20
Bag 150.00 7.80

Tables are now in Second Normal Form.

In the next section, we will take a look on the Third form of Normalization.

Advertisements

Liked it!  Share this Tutorial


Follow us on Twitter, or add us on Facebook or Google Plus to keep you updated with the recent trends of Java and other open source platforms.

Posted on: January 28, 2010

Ask Questions?    Discuss: Second Normal Form (2NF)  

Post your Comment


Your Name (*) :
Your Email :
Subject (*):
Your Comment (*):
  Reload Image
 
 
Comments
manoj
August 24, 2011
time picker control

i am looking for simple time picker control to integrate in my asp.net wea app. I got many such control but non worked.
danny
June 13, 2012
comment

impressive.....!!!!! 5 stars
dasfda
August 31, 2012
dasds

good
DMCA.com