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  1. #1
    Join Date
    Apr 2012
    Posts
    2

    Database Exam Question help- Functional Dependencies

    Can anyone please help me with this question. I have a huge exam on Monday and I really to learn this. Thanks!

    Consider a relation R(ABCDEGH) that satisfies the set of fuctional dependencies
    F={B--> DE , A--> CG, CD--> H, H--> A}, and the following decomposition of R into R1(H,G,C), R2(B, A, E) and R3 ( A,C, D, G)

    1. Write the projections in R1, R2 and R3 of the dependencies in (the closure of) F. Is the dependency H--> C in the projection in R1 of the dependencies in F?

    2. Answer if the decomposition of R into R1, R2 and R3 is dependency preserving (describe the condition that must be satisfied and clearly show whether it is satisfied or not).

    3. Write the definition of 3NF and answer whether R1, R2 and R3 are in BCNF (clearly explaning your answer).

    4. Write the definition of BCNF and answer whether R1, R2 and R3 are in BCNF (clearly explaning your answer).

    5. Select one of the decomposed relations (R1, R2, or R3) that is not in BCNF and apply the BCNF decomposition algorithm until all the resulting relations are in BCNF (clearly explaning each step of the algorithm)

    Thanks ALOTTTT

  2. #2
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    what do you have so far?
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  3. #3
    Join Date
    Apr 2012
    Posts
    2
    Quote Originally Posted by r937 View Post
    what do you have so far?
    Don't really know how to do functional dependencies... so nothing so far.

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