CS157A Lecture 15. 3NF and Boyce-Codd Normal Form. Prof. Sin-Min Lee Department of Computer Science San Jose State University. What it’s all about. Given a relation, R, and a set of functional dependencies, F, on R. Assume that R is not in a desirable form for enforcing F.
Functional Dependencies and Keys
Let X and Y be sets of attributes in R
X ® Y
Rules of the computation:
Example 1. Given R(a,b,c,d) a,c -> b,d a,d -> b
This example has demonstrated three things:
Only StudNo,Major is a candidate key.
In BCNF we have two tables
video(title,director,serial)customer(name,addr,memberno)hire(memberno,serial,date) title->director,serial serial->title serial->director name,addr -> memberno memberno -> name,addr serial,date -> memberno