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Thread: EER model help

  1. #1
    Join Date
    Nov 2010
    Posts
    1

    EER model help

    hi
    I need help in this assignment

    .. Taxi is assigned to a route which is comprised of stops on certain roads, the driver drives taxi according to availability....

    it is long one but I have problem in previous paragraph
    Entities: Taxi,route,stops,driver
    Taxi---route (1 to 1 relationship)
    route---stops(1 to many relationship )(right?)
    about the availability , how can I represent it?
    I just put relation between taxi and driver (1 to 1) but I do not think it is correct

  2. #2
    Join Date
    Sep 2002
    Location
    UK
    Posts
    5,171
    Nor do I, it appears to be a "many to many" because of the statement "the driver drives taxi according to availability". This implies:
    - sometimes driver A drives taxi X
    - sometimes driver A drives taxi Y
    - sometimes driver B drives taxi X
    - sometimes driver B drives taxi Y

    That implies a new relation, perhaps with a date to handle the "sometimes".

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