Re: quick FK question
From: Guillermo Alan Bort <cicciuxdba_at_gmail.com>
Date: Tue, 15 Dec 2009 18:31:40 -0300
Message-ID: <172762180912151331x6b214f2cl1135773067488193_at_mail.gmail.com>
ANSI definition of FK is that the value of the column to which the constraint applies, must be null or exists in a primary key on another table. Oracle extends that by allowing you to reference a non-pk column. But ANSI SQL supports null values in FK constraints (though not in the referenced column). The solution, indeed, is to set the not null constraint on the column.
Date: Tue, 15 Dec 2009 18:31:40 -0300
Message-ID: <172762180912151331x6b214f2cl1135773067488193_at_mail.gmail.com>
ANSI definition of FK is that the value of the column to which the constraint applies, must be null or exists in a primary key on another table. Oracle extends that by allowing you to reference a non-pk column. But ANSI SQL supports null values in FK constraints (though not in the referenced column). The solution, indeed, is to set the not null constraint on the column.
hth
Alan.-
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