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  1. #1
    Join Date
    May 2006
    Posts
    178

    Unanswered: My ERD Attempt...pls dont laugh

    Hi Guys,

    Trying to start from scratch, its my first attempt so please can you give me some suggestions.

    I havent put all the attributes as yest just put the keys.

    So..Open season .. let me hear it...


    Aboo
    Attached Thumbnails Attached Thumbnails myattempt.jpg  

  2. #2
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    kind of difficult to critique an ERD if we don't know what it's supposed to be doing

    one thing i noticed is that the materials, labour, and vehicle entities all have customerID as a foreign key

    this is redundant since the order that they belong to is already related to the customer

    also, what is "a labour"? can you point to a labour? how many labours will there be? how do you distinguish between 4 hours labour spent on Mr Smith's order and the 4 hours labour spent on Mr White's order?
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  3. #3
    Join Date
    May 2006
    Posts
    178
    Hi r937,

    Thanks for your reply.

    Labour is any labourers/staff/workers (agency workers)

    With each order, I want to be able to:
    -book vehicles if required by the customer.
    -book any any labour(personell) if required by the Customer.
    - and book any materials if required by the customer.

    As for the foreign key CustomerID, I used a little program called case Studio and it automatically put it in.

  4. #4
    Join Date
    Jun 2007
    Location
    London
    Posts
    2,527
    Quote Originally Posted by aboo
    I need some advice
    You should decide whether you want your post to remain in MS Access or whether it should be moved to db design, you shouldn't start 2 posts. A description of what the db does might also help.

    Shouldn't there be more fields in your tables like costs, prices and charges? Dates for when the work began, when it's scheduled to finish and when it actually finished might be useful. Do the materials need to just link with the order or with specific work as part of the order? Do materials need quantities etc? Obviously you're missing any contact info in the customer tables. Should the labour table link with a table for the supplier of that labour? Shouldn't there be details about the vehical and what work is required? Rudy has already commented that the customer id field is redundant in most of your tables.

  5. #5
    Join Date
    May 2006
    Posts
    178
    Hi Mike,

    As mentioned int eh post previously that the tool iw as using automatically inserted the foreign key into the tables.

    I didnt want to put in all the attributes as it would have made it massive so i just left the primary keys.


    There are no costs or charges.

    The Materials Just link to the order and have Qty's.

    The Labour Does not need a supplier, as with the materials it needs to link with the order.

    the Vehicle is just like Materials, if i run short of vehicles i can attach it to an order and get some in.

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