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  1. #1
    Join Date
    May 2007
    Posts
    2

    A doubt in normalisation

    Suppose there is a relation R(A,B,C,D)

    and the dependencies are :

    AB->CD
    C->B

    The relation is not in BCNF if there is a dependency of a proper subset(PS of a candidate key depending on a non key.

    Here the candidate keys are AC and AB, so it is like a PS->PS ...so which normal form is it not in

  2. #2
    Join Date
    Jan 2007
    Location
    UK
    Posts
    11,434
    Where's the question?
    Is this a homework assignment, if so, what class?
    This information will come in handy when trying to identify the answer
    George
    Home | Blog

  3. #3
    Join Date
    May 2007
    Posts
    2
    The question is
    Here the candidate keys are AC and AB, so it is like a PS->PS ...so which normal form is it not in

  4. #4
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    Quote Originally Posted by arunmagic
    Suppose there is a relation R(A,B,C,D)

    and the dependencies are :

    AB->CD
    C->B
    Since AB->CD, it is in "AB" form, or "ABnormal form".
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

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