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  1. #1
    Join Date
    Feb 2007
    Posts
    24

    Help with this ERD : kepp track of who change what.

    Hi,
    i'm new with DB design.
    I have to design an Entity-Relationship Diagram for my application in order to handle tha changes made to an entity.

    The original application deal with DOCUMENT and CONTACT entities and the SEND_TO relationship.



    ------------ (M) (N) ----------
    |DOCUMENT |-------< SEND_TO > -------|CONTACT|
    ------------ ----------

    Now STATE and USER entities need to be added to the project.
    A document can have one or more STATE during its lifecycle.
    I need to keep track of which user change the document's state.

    How can i model this in the ERD ?
    thanks.

  2. #2
    Join Date
    Feb 2007
    Posts
    24
    Do you think a ternary relationship DOCUMENT-USER-STATE could be the solution ?

  3. #3
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    I'd create copies of each table to maintain historical records and keep them updated with triggers.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

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