what are normalisation? explian in simple terms?

Database Normalisation refers to the process of organising and maintaining the data into the database in an efficient manner. The basic rationales behind normalising the database are: 

1. to eliminate the data redundancy i.e. to avoid/eliminate the storage of the same data at more than one places.
2. to ensure data dependency i.e. to store the related data in the database. 

Database Normalisation is a very important process as it makes the database free from storage of irrelevant data and removes the duplicate data items from the database. As a result, normalisation ensures more free space available in the database. In addition, normalisation also enhances the reliability and consistency of the database by protecting the database against the data anomalies such as logical and structural problems.