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  1. #1
    Join Date
    May 2010
    Posts
    3

    little normal form problem

    Hi there,

    I had a normal form problem, my relation is R(a, b, c, d) with functional dependencies of F = { [abc > d], [bcd > a], [a > b] }

    just wondering what the possible subsets of F are?

    Thanks

  2. #2
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    May is surely homework season on dbforums.
    If it's not practically useful, then it's practically useless.

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

  3. #3
    Join Date
    May 2010
    Posts
    3
    It's actually work related, but thanks for your reply.

  4. #4
    Join Date
    Feb 2004
    Location
    In front of the computer
    Posts
    15,579
    The possible subsets of F are:

    Scope 0: The empty set
    Scope 1: a, b, c, d
    Scope 2: ab, ac, ad, bc, bd, cd
    Scope 3: abc, acd, bcd
    Scope 4: abcd

    Just an observation, but there are a very small subset of people that use Relational Algebra for work. None of those people would ask this question. If you're going to try to blow smoke, at least try to blow plausible smoke.

    -PatP
    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

  5. #5
    Join Date
    Feb 2004
    Location
    One Flump in One Place
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    14,912
    Especially when you posted the problem earlier as an end of semester test question.

  6. #6
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    Quote Originally Posted by DB-pro View Post
    It's actually work related, but thanks for your reply.
    You are employed by a company that makes curly braces, perhaps?
    If it's not practically useful, then it's practically useless.

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

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