Re: View updating in practice?

From: Paul Vernon <paul.vernon_at_ukk.ibmm.comm>
Date: Mon, 11 Nov 2002 12:18:02 -0000
Message-ID: <aqo77c$itg$>

Jens Lechtenb÷rger" <> wrote in message
> > > Personally, I believe that view updates are dangerous in most
> > > situations as users cannot understand what is going on.
> >
> > This is similar to my general feelings to. It is my position that
> > unless views are 'information equivalent' to their underlying base
> > relvars (which is, I believe is equivalent to taking a constant
> > complement), then view updates should simply be seen as a
> > shorthand - a way for users to get the DMBS to generate base
> > update statements from the users desire of what the value of some
> > relational expression looks like.
> The constant complement approach is less restrictive. E.g., under
> constant complement you may issue UPDATE statements against
> projection views, or INSERT into selection views.

Fair enougth. Maybe I should have said an 'information equivalent subset'

Paul Vernon
Business Intelligence, IBM Global Services Received on Mon Nov 11 2002 - 13:18:02 CET

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