Re: foreign key constraint versus referential integrity constraint
Date: Thu, 29 Oct 2009 03:14:54 GMT
Message-ID: <OM7Gm.49744$Db2.21813_at_edtnps83>
Bob Badour wrote:
> paul c wrote:
>
>> Mr. Scott wrote:
>> ...
>>
>>> Constraints specify what can be true, not what is supposed to be
>>> true. ...
>>
>> I thought constraints constrain, ie., limit. (I've often thought that
>> isn't enough in practice, eg., I've never seen a default defined
>> algebraically and beyond that I wouldn't mind a variation on
>> constraints that lets me force an assertion, eg., some tuple that is
>> always present, whether the user has thought to include it or not,
>> probably CJ Date would disagree with that.)
> > I cannot make sense of what you wrote. I suspect you have omitted much > context, internal dialogue and assumptions.
I usually try to omit at least two out of three of those, otherwise even I can't guess what I'm talking about! Being of a minimalist persuasion, not wanting more concepts than I can handle, I think I'd rather have constraints, unlike CJ Date's, that are applied against values without requiring them to be 'truth-valued' and 'and-ed' if you will. I don't have a good name for this. Received on Thu Oct 29 2009 - 04:14:54 CET