Re: foreign key constraint versus referential integrity constraint
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Sun, 25 Oct 2009 00:56:24 -0300
Message-ID: <4ae3cbba$0$23758$9a566e8b_at_news.aliant.net>
>
> In RT, how could they not define equality?
Date: Sun, 25 Oct 2009 00:56:24 -0300
Message-ID: <4ae3cbba$0$23758$9a566e8b_at_news.aliant.net>
> Bob Badour wrote:
> ...
>
>> You asked about semantic joinability. Semantically, the join works if >> like-named attributes have an equality comparison defined and not if >> they don't. >> ...
>
> In RT, how could they not define equality?
What reason would one have to define an equality comparison to compare employee ids with department ids or with names? Or charge with current or potential? Or age with price? Received on Sun Oct 25 2009 - 04:56:24 CET