It's a technique through. which we can design the database. During normalization dependencies can be identified which can cause pbs during deletion & updation. It is used in simplifying the structure of table.
1st Normal Form - Un normalized data transfer to normalized form.
2ndNormal Form - Functional dependencies can be findout & decompose the table without loss of data.
3rd Normal Form - Transits dependencies, every non-key attribute is functionally dependant on just Primary Key.
4th Normal Form(BCNF)-The relation, who has multiple candidate keys, then we have to go for BCNF.
