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ER diagram HELP :(

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  • #1

    ER diagram HELP :(

    Okay, i'm trying to make an ER diagram for the following situation:

    You operate a library. The library has books. Each book has a BID, a name , and 1 or more authors. Each author has a name. The library has patrons. each patron has a PID and a name. patrons check out books. a book checkout record contains the date the book was checked out.


    Thanks in advance for the help!
    "Mal nommer les choses, c'est accroître le malheur du monde" - Camus (thanks Davout)

    "I thought you must be dead ..." he said simply. "So did I for a while," said Ford, "and then I decided I was a lemon for a couple of weeks. A kept myself amused all that time jumping in and out of a gin and tonic."
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  • #2
    thats way over my head but I'll bump it just to help you out.

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    • #3
      thanks buddy
      "Mal nommer les choses, c'est accroître le malheur du monde" - Camus (thanks Davout)

      "I thought you must be dead ..." he said simply. "So did I for a while," said Ford, "and then I decided I was a lemon for a couple of weeks. A kept myself amused all that time jumping in and out of a gin and tonic."

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      • #4
        Master artist!

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        • #5
          wow, that looks so simple I feel dumb now.

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          • #6
            close, but you are missing book check out record!?! I don't know how to show it...
            "Mal nommer les choses, c'est accroître le malheur du monde" - Camus (thanks Davout)

            "I thought you must be dead ..." he said simply. "So did I for a while," said Ford, "and then I decided I was a lemon for a couple of weeks. A kept myself amused all that time jumping in and out of a gin and tonic."

            Comment

            • #7
              Originally posted by Kaak
              close, but you are missing book check out record!?! I don't know how to show it...
              as a separate Entity?

              Comment

              • #8
                model an Entity 'date' which has a many-many relationship with 'checkout'?

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                • #9
                  /me reminds himself that he could do this stuff some time ago.
                  urgh.NSFW

                  Comment

                  • #10
                    Originally posted by radicus
                    Master artist!
                    Wasn't it suposed to be a many to many relationship between book and author?

                    One author could have written several books, while one book could be written by several authors?

                    Otherwise looks fine

                    /me reminds himself he's not that experienced in making those either...


                    A "Patron", is this the same thing as a customer?
                    This space is empty... or is it?

                    Comment

                    • #11
                      Originally posted by Kaak
                      close, but you are missing book check out record!?! I don't know how to show it...
                      The 'Check out' is a separate identity. it should be perfect for this.
                      urgh.NSFW

                      Comment

                      • #12
                        Originally posted by ADG
                        A "Patron", is this the same thing as a customer?

                        yup!

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                        • #13
                          Thx... learning new words every day
                          This space is empty... or is it?

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