Normalization is a technique of managing records in a database. It is an approach to eliminate data redundancy and anamolies . It also removes data duplicacy in a record. It helps in data update,delete and insert anamolies.Without normalisation,it becomes tough to handle database records.I illustrate an example to show how anamolies exists in a record or database.
Emp_id Emp_Name Emp_City Emp_Specialisation
1011 Akshat garg Mumbai C++
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1013 Suzan Arora Pune C++
1014 Shruti gupta Nanital PHP
There are three types of anamolies in a record.
Update Anamoly : data will become inconsistent,if there exist two or more type of similar data in a record.
Insert Anamoly : If we do vacant a data of a person or employee or any other kind of record, yet then also we have to insert NULL on that empty place of a respective record.
Delete Anamoly : If primary key of a record does not contains any data temporarily,so if we delete that row ,the whole record of database shall be deleted.
There are several types of normalizations.
1. First Normal Form
2. Second Normal Form
3. Third Normal Form
4. BCNF (Boyce and Codd Normal Form)
5. Fourth Normal Form
6. Fifth Normal Form