In my article on 3NF we saw that it was the same as 2NF but with one additional restriction. BCNF, similarly, is 3NF with one more restriction:
“Relvar R is in Boyce/Codd normal form (BCNF) if and only if, for every nontrivial FD X→Y that holds in R, X is a superkey.”
Date, C.J. Database Design & Relational Theory. Sebastopol: O,Reilly Media, Inc., 2012. Print. (Emphasis theirs)
2NF, 3NF, and BCNF are rules for evaluating functional depencies, or FD for short. If you are not familiar with the concept of functional dependency, please see my post on 2NF where I describe it in detail.
If you’re ready to tackle 3NF, then let’s begin! (more…)
Second Normal Form (2NF) is where we start analyzing the relationships of columns within a table to each other. (more…)