Re: What predicates the following relation represents
From: Eric Kaun <ekaun_at_yahoo.com>
Date: Wed, 31 Mar 2004 14:16:19 GMT
Message-ID: <ToAac.46100$jm6.6203_at_newssvr16.news.prodigy.com>
Date: Wed, 31 Mar 2004 14:16:19 GMT
Message-ID: <ToAac.46100$jm6.6203_at_newssvr16.news.prodigy.com>
"Mikito Harakiri" <mikharakiri_at_iahu.com> wrote in message
news:mrmac.22$mR.124_at_news.oracle.com...
> SALES
> =====
> PART SOLD
> ---- ---
> nuts 10
> nuts 15
>
> Is SALES a legal relation? Is database really a repository of facts?
Yes, a database is a repository of facts.
It's a legal relation, though the external predicate to which it corresponds may be nonsense. You can always define a candidate key over all the attributes - that doesn't mean it makes sense to do so. More likely they're talking about different sales events, which should have some sort of surrogate key identifier, or else distinguishing the above facts will be impossible other than by their contents (obviously). Received on Wed Mar 31 2004 - 16:16:19 CEST