NORMALISATION
Normalisationis a process of organizing the data in database to avoid data redundancyand anomalies . We have different levels of normal forms 1st,2nd, 3rd , BCNF ,4th,5th etc . A relation is always specified with its highest normalization level . First Normal Form defines that all the attributes in a relation must have atomic values . Second Normal Form is based on the concept of fully functional dependency . To be in second normal form, a relation must be in First Normal Form and every non-prim attributes are fully functionally dependent on any of the candidate keys. A relation is in 3rd normal form , 1)It must be in 2NF 2)Nonprime attributes should not be transitively dependent on candidate keys. For a relation to be in Boyce-CoddNormal Form (BCNF or 3.5 NF) , 1.It should be in theThird Normal Form. 2.And, for any dependency X→ Y, X must be asuper key. Stronger version of 3NF .