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What is Normalization? It’s a process of minimizing DATA redundancy. The main objectivity is to divide the table as an user friendly way to update, edit and delete any data without accessing each table. At the end we’ll be able to Insert, delete, update data without any problems.
INSERT ANOMALY: This refers to the situation when it is impossible to insert certain types of data into the database.
DELETE ANOMALY: The deletion of data leads to unintended loss of additional data, data that we had wished to preserve.
UPDATE ANOMALY : This refers to the situation where updating the value of a column leads to database inconsistencies (i.e., different rows on the table have different values).
Different levels of Database Normalization
1st Normal Form (1NF)
2nd Normal Form (2NF)
3rd Normal Form (3NF)
Note There are 5 Normalization Forms, We are only focusing 3 of them.
1st Normal Form (1NF)
The Database in First Normal form should completed the below conditions.• Contains only non dividable values (Atomic Values).• No Replica (Cannot contain Duplication).• It Should be in un-normalized Form.
Item ID Item Cost (Rs.)
A001 Rata Kaju, Idiyappa 70
A002 Lemonade 30
A003 Spaghetti 150
A004 Lemonade 40
A005 Kottu 160
Item ID Cost (Rs.)
A001 70
A002 30
A003 150
A004 40
A005 160
Item ID Item
A001 Rata Kaju
A001 Idiyappa
A002 Lemonade
A003 Spaghetti
A004 Lemonade
A004 Kottu
Product Table
Product Price Table Item Table
2nd Normal Form (2NF)
The Database in Second Normal form should completed the below conditions.• It Should be in 1st Normal Form.
• All Non-Keys should be dependent to the Primary Key.
NoteNon-key attributes are attributes other than candidate key attributes in a table.
Purchase ID Bar Code ID Store Location
A001 Bar001 Left Store
A002 Bar002 Underground Store
A001 Bar001 Left Store
A004 Bar003 Main Store
A004 Bar002 Underground Store
Purchase ID Bar Code ID
A001 Bar001
A002 Bar002
A001 Bar001
A004 Bar003
A004 Bar002
Bar Code ID Store Location
Bar001 Left Store
Bar002 Underground Store
Bar003 Main Store
Composite Key Purchase Table
Purchase Bar Code Table Item Location Table
3rd Normal Form (3NF)
The Database in Third Normal form should completed the below conditions.• It Should be in 2st Normal Form.• There is no transitive functional dependency.
Class ID Course ID Course Name
Re001 0037 Computer Science Yamanato
Re002 0045 Cookery Jhon
Re001 0037 Computer Science Khan
Re002 0045 Cookery Elina
Re005 0016 Fashion Designing Suman
Class ID Course ID Name
A001 0037 Yamanato
A002 0045 Jhon
A003 0037 Khan
A004 0045 Elina
A005 0016 Suman
Course ID Course
0037 Computer Science
0045 Cookery
0016 Fashion Designing
Composite Key Student Registry Table
Student Registry Name Table Course Table