functional dependencies

This is a discussion on functional dependencies within the C++ Programming forums, part of the General Programming Boards category; Is anyone familiar with a C++ library that is designed for decomposing database functional dependencies??? Any help is appreciated. Thanks ...

  1. #1
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    functional dependencies

    Is anyone familiar with a C++ library that is designed for decomposing database functional dependencies??? Any help is appreciated.

    Thanks in advance

  2. #2
    Banned master5001's Avatar
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    Someone can go ahead and correct me if I'm wrong but there is not any such library in the standard C++ library. There may be some proprietary library out there but it would also be dependant on the database (obviously) therefore I doubt there is a library out there that does exactly what you want. However, necessity is the mother of invention right?

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    UNBANNED OneStiffRod's Avatar
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    Just for my knowledge can someone explain...

    decomposing database functional dependencies
    ??? what do you mean by functional dependencies??
    My Avatar says: "Stay in School"

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    well

    Functional dependencies deal with relations among attributes in a database. Kinda like what attributes are dependent upon other attributes - thus the term functional dependency.

    Peace

    Say for instance

    a -> b
    bc -> r

    etc.

    -> denotes the word "determines" ("a determines b") is an example

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    Guest Sebastiani's Avatar
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    Is anyone familiar with a C++ library that is designed for decomposing database functional dependencies???
    For which database, and free or proprietary?
    Code:
    bool fun(bool value)
    {
        return std::pow(std::exp(1), std::complex<float>(0, 1) 
        * std::complex<float>(std::atan(1)*(1 << (value + 2))))
        .real() > 0;
    }

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    not in particular

    I am speaking from a theoretical point of view. No particular database explicitly. FD's are looked at strictly from the design aspect. i am working on some code that will help during the design of the database.

    Am I shooting myself in the toe? The more and more I think about it, the more I think that the FD library doesn't exist.

    Peace

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    Guest Sebastiani's Avatar
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    Well, they may, but not to my knowledge . But I'd certainly write you one!
    Code:
    bool fun(bool value)
    {
        return std::pow(std::exp(1), std::complex<float>(0, 1) 
        * std::complex<float>(std::atan(1)*(1 << (value + 2))))
        .real() > 0;
    }

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    developing

    I am certainly interested in developing this code. If successful, then I would certain add it to my personal C++ class library. I'm not that proficient yet, but I do plan on spending lots of time with this...

    Thanks for everyone's input. As a matter of fact, I found some pseudocode for the algorithm. However, implementation is a my shortcoming. At this point, I am unaware of many C++ functions and methods calls....

    Peace

  9. #9
    UNBANNED OneStiffRod's Avatar
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    I know this post is old, but here's a link to an entire college course on Database systems and FD's.

    http://www.cs.uh.edu/~marek/cosc6340.html

    click on the lectures...
    My Avatar says: "Stay in School"

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  10. #10
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    Do you want an algorithm that takes something like
    A depends on B
    E depends on F
    B depends on E
    and the deduces that A depends on F.

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    on target

    Nick, you are right on target. I have managed to complete my first task which is to make new relations by minimizing the right-side attributes, and writing to output to a new file.

    For instance:

    AB -> FGH is decomposed into

    AB -> F
    AB -> G
    AB -> H

    Now, I am trying to find the redundancies within my new output file. But yes, Nick, you are precisely on target.

    OneStiff, I will check the link. Thanks.

    Any input, I will accept.

    Peace

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