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databasefunctional-dependenciescanonicalization

Canonical Cover example

I'm learning for my exams in the course databases and have some problems with the functional dependencies.

So I got the functional dependencies:

A->BE, AE->BD, F->CD, CD->BEF, CF->B

After decomposition and left-reduction I get:

A->B, A->E, A->D, F->B, F->C, F->D, CD->B, CD->E, CD->F

So after checking for transitivity's I get as solution:

A-> BDE, F->CD, CD->BEF

But I'm not sure if its right. I did the same steps like in this tutorial here:

http://www.youtube.com/watch?v=lKYz5e7INTg

Thanks for any help!

Solution

  • Well I found this page to calculate the canonical cover:

    http://www.koffeinhaltig.com/

    Important for the input is that between each attribute there must be a space.

    So I found out that my solution is correct.

    Here is my example:

    http://www.koffeinhaltig.com/fds/ueberdeckung.php?fds=A+-%3E+B+E%2C+A+E+-%3E+B+D%2C+F+-%3E+C+D%2C+C+D+-%3E+B+E+F%2C+C+F+-%3E+B&language=de