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  1. #1
    Join Date
    Aug 2015

    Decompose a relation into BCNF and 3NF

    I am new to DB concepts and development and am having trouble with the below.

    I have determined that for the relation R(A,B,C,D,E,F,G,H,I) where:

    {A -> B,C} {E -> F} {D -> I} {A,D -> G} {G -> H}

    ...that the primary (and only) key is A,D,E.

    Is it therefore safe to deduce that from this, it is not in 3NF and not in BCNF because of the FD G -> H?

    Also, if this deduction is correct, how do I decompose into BCNF and 3NF?

    Any help is greatly appreciated.

  2. #2
    Join Date
    Feb 2012
    You're correct that the FD G -> H breaks 3NF and BCNF, though that's not the only FD at fault. Every other FD violates 2NF. Start decomposing R into a set of 2NF relations, then 3NF and BCNF.

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