Question: how bcnf is better than 3nf?
Answer: BCNF is a stronger form of normalization than 3NF because it eliminates the second condition for 3NF, which allowed the right side of the FD to be a prime attribute. Thus, every left side of an FD in a table must be a superkey. ... A table is in BCNF if every functional dependency X → Y, X is the super key of the table.