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

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.

David Meador

Published on 03-Jul-2018 12:00:54