Re: does a table always need a PK?

"Tony Douglas" <tonyisyourpal_at_netscape.net> wrote in message news:bcb8c360.0309020609.d571f6b_at_posting.google.com...
> "Paul Vernon" <paul.vernon_at_ukk.ibmm.comm> wrote in message
news:<bj0d5h$1fbc$2_at_gazette.almaden.ibm.com>...
>
> > I'm sure that some math/thoery could be/has been built that takes into account
> > parameters such as MTBF and other 'risk factors', combined with requested
security
> > margins (1 in X chance of loosing 1 bit of data) so that some rigour can be added
to
> > stuff like backup policies.
> >
> Indeed, but that's not quite the angle I was approaching this from; I
> was thinking more of, how could you write an expression of the lambda
> calculus (however sugared) that could derive a worthwhile
> specification in a suitably formal style of what backups (and other
> such things) mean; I doubt that you can, although I'd love to be
> proved wrong !

I doubt that lambda calculus is the correct level of abstraction here. Concepts such as risk, financial cost etc don't mean much at that level. Not everything can be understood at the same level of abstraction.

Regards
Paul Vernon
Business Intelligence, IBM Global Services Received on Tue Sep 02 2003 - 20:15:19 CEST