Tutorial By Namitha

Normalization is the process of minimizing redundancy and eliminating anomalies from a relation or a set of relations.  Decomposition of a relation is done when a relation is not in required normal form .   We can decompose a relation into two or more relations if decomposition is lossless join as well as dependency preserving.  Upto 3rd normal form both of these decomposition properties we need to preserve.  Given a relation R after decomposing R into R1 and R2  , If R1 join R2 =R ,then the decomposition is said to be lossless join decomposition . If R1 join R2 is ⊃ R ,then the decomposition is said to be lossy decomposition .