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  1. #1
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    Unanswered: Normalisation assistance

    So I have this project I have to do and I know how to normalise if I were given the dependencies to 3NF. But in this case I'm not and have to work out the dependencies on my own which I have done to some extent.

    What is hindering my ability to normalise this table(s) is that there are 4 tables each with their own cargo type. I tried normarlising it as a whole but it got too difficult. Would it be right in saying that I can normalise table P01, P02, P03, P04 individually?

    Another problem with doing it individually is that in P04 the 20ft-DRY container is also used for DRY01 and RUG01, which means i would have to make them a Primary key, Container_Model and Container_Code.

    Table:
    table.jpg

  2. #2
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    The four tables are not really four tables. You have just been confused by the way they are laid out. Really, the identifiers for the tables could be added as a column in a single table.
    Then you can start to identify your entities and dependencies.
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  3. #3
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    As far as I can see there is no difference between the 4 tables with the sole exception of the type of cargo they can carry. so to me they are one entity with a new table that identifies what type of cargo which becomes a FK in your current table.

    the only wrinkle is if a type of cargo may be carried in more than one type of vehicle.

    You may need to revisit your vehicle types and whilst you are at it the container types

    on the face of it the chargeout rate seems to be tied to the class of vheicle not to the vehicle itself, so mebbe you need to reconsider that

    can any container be fitted to any vehicle if so you need to revisit that

    the fact that you are duplicating the vehicle registration suggests you haven't normalised this at all

    in short do you actually think you have done any normalisation yet?

    when's the assignment due?

    Fundamentals of Relational Database Design -- r937.com
    The Relational Data Model, Normalisation and effective Database Design
    are both good texts on what you need to look at and work on
    I'd rather be riding on the Tiger 800 or the Norton

  4. #4
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    Mark - I think this is the raw assignment data. As such, you might have done a little more work than you intended
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  5. #5
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    Guilty yerhonner, I feel a NZDF normalisation could be on the cards
    I'd rather be riding on the Tiger 800 or the Norton

  6. #6
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    The assignment is due in a couple of days to be done in partners and the other guy is pretty useless. Whats NZDF?

    Yeah these are tables that have not been normalised at all. I will post up what I think a 3NF table is, soon.

  7. #7
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    NZDF is a form of normalisation used to refine the model to its preferred stage, its an especially powerfull tool when used in assignments and homework.
    I'd rather be riding on the Tiger 800 or the Norton

  8. #8
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    Yes - get to 3 NF and show us how you did.
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  9. #9
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    I'm back.

    Actually I'd like to say that the table is in 1NF. My reasoning is everything is atomic, there are no repeating groups, besides the seperate 4 tables but the purpose of the truck is clearly defined by the function.

    However I don't think i can just ignore the Description attribute because there seems to be a link to the truck_container_hire_rate and the Description.
    Last edited by kimitsu; 04-22-09 at 13:59.

  10. #10
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    I got some assistance today with our tutor and this is what I came up with:

    3NF:
    RECORD (number, description)

    REC-num (number, rego_num, container_code)

    REC-TRUCK (rego_num, truck_class, truck_make, truck_model)


    REC-CONTAINER (container_code, container_model, load_capacity, dimension, function)

    REC-CONHIRE (rego_num, container_code, truck_container_hire_rate)

    REC-TRUHIRE (truck_class, driver_hire_rate)
    Last edited by kimitsu; 04-23-09 at 10:34.

  11. #11
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    I'm glad you are happy.

    BTW - 1 NF requires a key!
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  12. #12
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    Sorry, fixed.

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