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  • ISHAN TOPRE

    ISHAN TOPRE

    @ishan-nohePN • Mar 18, 2011

    Re: Functional Dependencies

    Also see this! 😛

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  • kevin88

    kevin88

    @kevin88-yh4fvl • Mar 19, 2011

    Hello

    I am having a problem understanding dependency theory using Armstrong's Axioms, I have researched this online and I understand the axioms however I am struggling to understand a particular example. Can anyone provide me with any advice or help?

    Can I post the example here?

    Thank you

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  • ISHAN TOPRE

    ISHAN TOPRE

    @ishan-nohePN • Mar 19, 2011

    Yes of course you can post your query here. Our CS/IT people will try to explain you the theory so that you will be able to solve your problem. 😀

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  • kevin88

    kevin88

    @kevin88-yh4fvl • Mar 19, 2011

    Thank you ishutopre

    I have two examples with answers but I do not understand how the answer has been derived:

    Example 1:
    Given
    R < A= {V,W,X,Y,Z},
    Gamma = { 1. V -> Y, 2. YW -> Z
    3. Y -> W}>

    RTP(required to prove) VWY -> Z and VXY ->Z

    Answers:
    VWY -> WY -> Z
    VXY -> Y -> YW -> Z
    augment 3 by Y Y -> W

    Example 2:
    Given the following relation
    R < A = {M,N,O,P,Q,R,S},
    Gamma = {Q->MO, S->R, M->SP}>

    prove that PM->R

    Answer:
    PM -> SP -> S -> R
    M -> SP augment by P

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