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  1. #1
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    Solved ...

    thanks all .....
    Last edited by njad; 12-14-11 at 22:48.

  2. #2
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    1 yes

    2 weak entity has a relationship where the FK is ~not~ part of the PK, but 1:N or M:N is determined by the entities themselves

    3 yes

    4 no, data attribute

    5 not 1:N, rather N:1

    6 book to author is M:N, article is not involved
    rudy.ca | @rudydotca
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  3. #3
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    thanks ...
    Last edited by njad; 12-14-11 at 22:46.

  4. #4
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    ..........
    Last edited by njad; 12-14-11 at 22:46.

  5. #5
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    ..........
    Last edited by njad; 12-14-11 at 22:46.

  6. #6
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    1) No. What?
    4) Probably not.
    5) No, see the r937's response
    6) Correct.

    -PatP
    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

  7. #7
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    thanks .......
    Last edited by njad; 12-14-11 at 22:47.

  8. #8
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    Quote Originally Posted by njad View Post
    Is that means make relationship between publishers and books name it for example "publise_book"and make other between publishers and journals called "publish_journal"?
    that sounds right
    rudy.ca | @rudydotca
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  9. #9
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    thanks all..
    Last edited by njad; 12-14-11 at 22:44.

  10. #10
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    thanks all ......

  11. #11
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    Quote Originally Posted by njad View Post
    Hi ..
    I want the ER diagram for these requirments:
    "A bookstore database maintains information about books, professional journals, their authors and publishers. Books and journals are collectively referred to as publications that are published by publishers. All publications have a serial number (ISBN), a title and a year of publication. Books have an edition number whereas journals have a volume and number. No book or journal is published by more than one publisher. Journals contain articles. A book or an article can have one or more authors. Articles have a title and a subject category and no article can appear in more than one journal. Authors have a SSN, name and date of birth, whereas a publisher has a name and address." thanks ..
    No problem, glad to have helped you!

    -PatP
    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

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