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  1. #1
    Join Date
    Aug 2006
    Posts
    10

    Normalisation Q's...

    hi all,

    I am currently working on a database with lots of weird values in it. It was originally a spreadsheet, and I need to make it a database (and its a pretty bad spreadsheet too)

    Here is a the UNF representation

    UNF (Date, Client, Address, Contact, Helicopter, Pilot, Charter_Type, Cost_Per_Hour, Passengers, Leg, ETA, ETD, Origin, Destination, ATA, ATD, Engine_Time, Total_Engine_Time, Special_Requirements)

    The Leg field has a value of 1, 2, 3 etc, but this may be duplicated as there can be multiple Clients. I am thinking of using the Client and the Leg as an initial composite PK.

    Basically I work it as following (PKs are in bold)

    1NF

    CHARTER (Date, Client, Address, Contact, Helicopter_Number, Pilot, Charter_Type, Cost_Per_Hour, Passengers, Leg, ETA, ETD, Origin, Destination, ATA, ATD, Engine_Time, Total_Engine_Time, Special_Requirements)

    So to cut it down, I have four relations at the end

    Client (Client, Address, Contact)

    Leg(Leg, Date, ETA, ETD, Origin, Destination, ATA, ATD, Engine_Time)

    Helicopter(Helicopter_Number, Cost_Per_Hour)

    Charter (Passengers, Total_Engine_Time, Special_Requirements, Charter_Type, Pilot)

    Thing is, I have no PK for the Charter relation, should I just invent one??

    If somebody could clear this up, I would appreciated it, and I apologise for being daft! I have read a number of guides on Normalisation, but nearly all assume there is one attribute that is obviously the PK...

  2. #2
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    Define "charter". Define "leg".

    I see nothing in your proposed schema that relates any of the tables to one another, and that is going to be a problem for you.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

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