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  1. #1
    Join Date
    Jan 2014

    Help needed: Normalizing 1NF to 2NF,3NF with functional dependencies

    Hello guys,

    I have translated a document for a "cleaning company" to UNF and then to 1NF with atomic values (attached with this post)

    I have identified a "Superkey" for 1NF: building, apartment, day, cNumber
    I think this is the minimal set required for identifying a unique tupel
    building, apartment, day, cNumber -> sNumber, Sname, cName, hourlyWage

    sNumber,Sname is the supervisor/responsible for the cleaners
    cNumber, cName stands for cleanerNumber,cleanerName

    Functional dependencies:
    FD1: sNumber -> sName (name can be dupe)
    FD2: cNumber -> cName (name can be dupe)
    FD3: building -> sNumber
    FD4: cNumber, building, day -> hourlyWage (unsure about this one, there are som dupes, 5,B,Friday and 5,B,Tuesday all leads to 10.7 in hourlyWage)

    I can only use the attributes + FD that is building, apartment, day, cNumber?
    FD2: cNumber -> cName
    FD3: building -> sNumber
    FD4: cNumber, building, day -> hourlyWage


    cNumber, cName

    1: Anette Torres
    3: Richard Howard
    4: Louise Lewis
    5: John Toney
    6: Carol Connel
    7: Janet Hagan

    building, sNumber, sName

    A:2:Lillian Weber
    B:5:Billy Collins
    C:5:Billy Collins
    D:7:Lillian Weber

    cNumber, building, day, hourlyWage
    .... (cut to save space)
    Where cNumber is referenced to 2NF_Cleaners and building is referenced from 2NF_Responsible

    How would you design the relations so they are in 2NF and 3NF? i have tried to solve this one for about 2 weeks

    Attached Thumbnails Attached Thumbnails 1NF.v1.png  

  2. #2
    Join Date
    Feb 2004
    In front of the computer
    I'd suggest that you start with Marc Rettig's Normalization Poster, then post any specific questions that you have. We'll help you with specific questions like "I could split the widgets entity into sprockets and dinguses, or I could split widgets into multiple thingies with timestamps... Which of those meets 3NF?" but its very unlikely that anyone at DBForums will take your design from 2NF to 3NF for you.

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

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