"Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message
news:aQCD9.82028$g9.231495_at_newsfeeds.bigpond.com...
> Are you as old as me then? Or is it still on the radio??!
>
> Regards
> HJR
>
> "Paul Brewer" <paul_at_paul.brewers.org.uk> wrote in message
> news:3ddea001_2_at_mk-nntp-1.news.uk.worldonline.com...
> > "Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message
> > news:cAeD9.81459$g9.229455_at_newsfeeds.bigpond.com...
> > >
> > > "Paul Brewer" <paul_at_paul.brewers.org.uk> wrote in message
> > > news:3ddd6f87$2_3_at_mk-nntp-1.news.uk.worldonline.com...
> > > > "Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message
> > > > news:FYVC9.80802$g9.227327_at_newsfeeds.bigpond.com...
> > > > > Whatever happened to Boyce-Codd Normal Form, huh??
> > > > >
> > > > > Huh?
> > > > >
> > > > > Come on... TNF is for wimps.
> > > > >
> > > > > Regards
> > > > > HJR
> > > > > ;-)
> > > > >
> > > > Howard,
> > > >
> > > > Have to (yet again) confess ignorance. I am familiar with Uncle
Ted's
> > > > principles, but I have never heard of Mr. Boyce.
> > > > Is this 4NF and 5NF? (Attribute, Value pairs) and all that stuff? If
> so,
> > > I'd
> > > > theoretically like the idea of designing the entire application in
one
> > > > table, but I might have a slight concern about how it would
eventually
> > > > perform in the real world <g>
> > > >
> > > > Regards,
> > > > Paul
> > >
> > > Are you sitting comfortably? Then I shall begin.
> > >
> > > A relation is in Boyce-Codd Normal Form (BCNF) if every determinant is
a
> > > candidate key.
> > >
> > > Or, as I saw it put more pithily (and accurately, if more
inscrutibly):
> > >
> > > relation R with FDs F is in BCNF if, for all X ? A in F+
> > > (where X contains a key for R)
> > >
> > > Got that? No??
> > >
> > > In other words (hold on to your hats):
> > >
> > > R is in BCNF if the only non-trivial FDs over R are key constraints.
> > >
> > > From this it follows (follows???!) that there is no dependency in R
that
> > can
> > > be predicted using FDs alone, and also that if we are shown two tuples
> > that
> > > agree upon the X value, we cannot infer the A value in one tuple from
> the
> > A
> > > value in the other.
> > >
> > > Dontyajustlurve this stuff??!
> > >
> > > I confess to having lifted this lock, stock and several smoking
barrells
> > > from a couple of sites trawled after searching on Google.
> > >
> > > All I really know about BCNF in plain English is that it is more
> > normalised
> > > than 4NF or 5NF. It is, in fact, the most normalised you can get -it's
> > > actually theoretically impossible to normalise further than good old
> BCNF.
> > > Which is why no-one uses it because attempting to do so would burst
> > several
> > > blood vessels in the brain and result in absolutely abysmal
performance.
> > >
> > > But I like trotting it out at dinner parties, just to impress.
> > >
> > > The last dinner party to which I was invited was in 1986. I wonder
why?
> > >
> > > :-)
> > >
> > > Regards
> > > HJR
> > >
> > >
> >
> > Howard,
> >
> > Quite straightforward, then.
> > I'm looking forward to explaining this to the business....
> >
> > By the way, on the 'sitting comfortably' question, I checked:
> >
> > pb> lsnrctl status
> >
> > LSNRCTL for 32-bit Windows: Version 9.2.0.1.0 - Production on
22-NOV-1957
> > 13:45:00
> >
> > Copyright (c) 1947, 1956, Oracle Corporation. All rights reserved.
> >
> > Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC0)))
> > STATUS of the LISTENER
> > ------------------------
> > Alias LISTENER
> > Version TNSLSNR for 32-bit Windows: Version
9.2.0.1.0 -
> > Service "Mother" has 1 handler(s) for this service....
> > The command completed successfully
> >
> >
> > Regards,
> > Paul ;-)
> >
> >
> >
>
>
The former, it appears, unfortunately.
Regards,
Paul
Received on Sat Nov 23 2002 - 13:01:21 CST
