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  1. #1
    Join Date
    Mar 2006
    Posts
    43

    Unanswered: Deferred checking

    Apparently MySQL does not support deferred checking. I know in basic terms what deferred checking is, but I'm not sure what implications having it (or not having it) in your DBMS is.

    Could somebody please explain why the MySQL documentation explains that without deferred checking, having a foreign key reference its own row is not possible? I'm not sure why that is... (And did it mean when the foreign key references its own row, or when it references any other row in the same table?)

    Also, apparently for ON DELETE/UPDATE, NO ACTION and RESTRICT are the same because there's no deferred checking. The docs say it's because ON DELETE/UPDATE NO ACTION is with deferred checking, but I just can't wrap my head around understanding why this is...

    Any help on this would be great, thanks a lot.

  2. #2
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002

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