BCNF

From: <aarklon_at_gmail.com>
Date: Fri, 1 Aug 2008 02:44:07 -0700 (PDT)
Message-ID: <3a1e04e9-e65f-469f-8357-f36486009e72@b38g2000prf.googlegroups.com>


Hi all,

BCNF   the following is the definition is the definition of BCNF , which i saw in a schaum series book

  1. The relation is 1 N.F
  2. for every functional dependency of the form X -> A , we have either A C X or X is a super key of r. in other words, every functional dependency is either a trivial dependency or in the case that the functional dependency is not trivial then X must be a super key.

 now my questions are as follows

1)

we know that 2-ND normal form is all about separating partial dependencies and full dependencies.third normal form is all about removing transitive dependencies, in these lines can any one give simple/ easy to understand method/explanation for converting a relation in 3rd normal form to BCNF

2) how correct is the following definition of transitive dependencies

  transitive dependencies

 assume that A,B, and C are the set of attributes of a relation(R). further assume that the following
 functional dependencies are satisfied simultaneously : A -> B , B -/-
> A, B -> C , and C -/-> A and A -> C

 observe that C -> B is neither prohibited nor required. if all these conditions are true, we will say that attribute C is transitively dependent on attribute on A Received on Fri Aug 01 2008 - 04:44:07 CDT

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