Help Me/Question Difference Between Third Normal Form And Bcnf?


Yellow Belt
  • A relation is said to be in third NF if and only if, it is in second NF and no non-key attribute is transitively dependent on primary key whereas, a relation is said to be in BCNF if and only if every determinant is a candidate key.
  • Third normal form is weaker than BCNF whereas BCNF is stronger than third NF as it removes all the anomalies of the 3NF which occurs because of overlapping candidate key.
  • Third NF has reference to first and Second NF whereas BCNF does not refer to First and Second NF.
  • The relation not in BCNF could be in 3NF whereas The relation not in 3NF could never be in BCNF.
  • 3NF could contain overlapping candidate key whereas BCNF could not contain overlapping candidate keys.

Swati Mishra

Yellow Belt
BCNF is the boyce codd normal form, BCNF is more stricter then 3 NF and the left side of any functinal dependency in the table must be super key.