Database Normalisation is a technique of organizing the data in the database. Normalization is a systematic approach of decomposing tables to eliminate data redundancy and undesirable characteristics like Insertion, Update and Deletion Anamolies. It is a multi-step process that puts data into tabular form by removing duplicated data from the relation tables.Check this link to better understand

https://www.mindstick.com/Articles/855/introduction-to-database-normalization

http://agiledata.org/essays/dataNormalization.html

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