5NF is the most important normal form in which we can decomposing the degree of complex tables and it also known as project-join normal form (PJ/NF) is a level of database normalization designed to reduce redundancy in relational databases recording multi-valued facts by isolating semantically related multiple relationships. A 5NF is put on the relation if R is already in 4NF and It cannot be further non-loss decomposed. A table is said to be in the 5NF if and only if every non-trivial join dependency in it is implied by the candidate keys. 5NF consideration must be given to tables where this non-loss decomposition can only be achieved by decomposition into three or more separate tables.