Re: Negative Numbers in "Identity" or" Autonumber" fields

From: paul c <>
Date: Wed, 21 Mar 2007 22:25:06 GMT
Message-ID: <6hiMh.48103$zU1.31726_at_pd7urf1no>

Marshall wrote:
> On Mar 21, 6:26 am, "David Cressey" <> wrote:

>>However, the word "only" in your post means something like "less than"
>>conveys no information.
>>This is not the case for the numbers one takes for service at the deli
>>counter.  If they say "now serving 72" and my number is 73,  that tells me
>>something.  Or am I misreading you.

> [There were four posts asking me what I meant; I'll reply to this
> one.]
> The idea is a type for which the only operator defined is '='. If
> we have two values of this type, we can tell whether they are
> the same, and that's all we can tell. Further we have a way to
> acquire a value of this type that has not been used in the current
> system state before.
> ...

Maybe I'm taking the original post out of context, but I didn't understand why the question was asked one time, let alone four. A domain that doesn't include some identity operator would be pretty useless in practice - one wouldn't know whether one was looking at a set of tuples or a bag of tuples, one couldn't join relations, etc.

p Received on Wed Mar 21 2007 - 23:25:06 CET

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