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aarklon@gmail.com
 
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Default BCNF - 08-01-2008 , 04:45 AM






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 -/-
Quote:
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



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