Database Normalization
Database Normalization removes redundancy of data and anomalies in a poorly designed table. The process of normalization converts an unnormalized table in a normalized form.
Let us see what flaws are in an Unnormalized table i.e. why Normalization of Database is so crucial −
Redundancy of Data
Storing same data item multiple times is known as Data Redundancy.
Let us see an example −
We have an <Employee> table that has a field to store current address of Employees. Some of these employees are given a place to live by the company; therefore, they have the same address. The address will be repeated in the database −
Table 1.1
EmpID
| EmpName
| EmpAddress
|
E001
| Emma
| 20, Street 17, Connecticut
|
E002
| Jack
| 20, Street 17, Connecticut
|
E003
| Adams
| 20, Street 17, Connecticut
|
E004
| John
| 21, Street 17, Connecticut
|
E005
| Rocky
| 21, Street 17, Connecticut
|
To solve it, store the employee address in a separate table and point in the <Employee> table.
Updation Anomaly
It occurs when you face issues while updating a table.
Deletion Anomaly
Let’s say the company decide to close a Department in the company, then the deletion of row would also lead the deletion of that employees data.
Insertion Anomaly
It occurs when you try to insert data in a record that does not exist.
Normalization removes all the above issues/ anomalies and gives you a normalized perfect database design that a database administrator love.
Published on 03-Jul-2018 12:00:54
