Re: One-To-One Relationships

On Nov 30, 1:03 pm, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> JOG wrote:
> > On Nov 30, 12:53 am, David BL <davi..._at_iinet.net.au> wrote:
>
> >>On Nov 30, 7:34 am, JOG <j..._at_cs.nott.ac.uk> wrote:
>
> >>>On Nov 28, 10:37 pm, paul c <toledobythe..._at_ooyah.ac> wrote:
>
> >>>>Bob Badour wrote:
>
> >>>>>rpost wrote:
>
> >>>>...
>
> >>>>>>This is the exact problem Chen identified. In the relational model
> >>>>>>it is impossible to have entity-valued attributes, which, in practice,
> >>>>>>we have a huge amount of.
>
> >>>>>Entities are figments of our imaginations.
> >>>>>...
>
> >>>>That's much better than my reply, looks like the essential point to me.
>
> >>>Entities are concepts that we impose on that which is there (mostly
> >>>shapes made out of atoms, but sometimes abstractions too).
>
> >>>Entities are 'real' in that they are patterns that we think up and
> >>>apply, and 'not real' in that if we were all dead, well there wouldn't
> >>>be any 'entities' would there. Just atoms again.
>
> >>Is this merely an argument against mathematical realism or something
> >>more specific?
>
> > I haven't argued anything, I have just defined entities. All seems
> > like common sense to me.
>
> >>>Because we conjure them up 'entities' aren't neatly defined, can
> >>>overlap, change, and will differ from person to person. In fact its a
> >>>testament to the amazing flexibilty of our noggins that that we
> >>>manage to communicate at all.
>
> >>Do you consider all mathematics to be "conjured up" and therefore not
> >>neatly defined as well?
>
> > Non-sequitur. I have made no comments on mathematics nor on anything
> > being ill-defined.
>
> > What I am suggesting is that given the contextual nature of how we
> > define any given entity, any model centered upon them is going to have
> > a very inflexible, brittle view of the world.
>
> > There are a load of atoms. Someone else looks at them and says hey its
> > a dead bit of wood, its a 'stump' entity. Someone else considers a
> > bigger picture and says its a snapshot of a 'tree' entity. Me, being
> > lazy, say hey I could sit on that, its a 'seat' entity, etc., ad
> > infinitum.
>
> > Whos right? Noone. Everyone. Who cares. It just depends on the
> > context, and with shared data, thats gonna vary. So lets encode the
> > underlying bloody information, and not whatever brittle view of the
> > world that first pops into our heads, ending up with a brittle,
> > creaking database.
>
> >>>And as such, anyone who tells you that you can build a permanent, all
> >>>encompassing model out of such utterly woolly things is not to be
> >>>trusted as far as you can throw them.
>
> >>>P.S I have also had similar experinces at Ikea :) I don't follow the
> >>>arrows anymore. They lie.
>
> >>If there is a valid argument against "entities" I would hope it can be
> >>stated more carefully than your or Bob's attempts.
>
> > Again I haven't argued against entities. However, I am of course
> > interested in what you deem invalid in my comments.
>
> He didn't like the figment argument? I thought it was careful and quite
> clear. Perhaps, I should elaborate:
>
> Entities are subjective and products more of applied psychology than
> applied mathematics.

Good, it's not a metaphysical argument.

How does one interpret a tuple as a proposition about the real world if one avoids any conception of entities?

It seems to me that some entities are inevitable. Can't the distrust of entities be stated without throwing the baby out with the bath water? Received on Fri Nov 30 2007 - 06:20:24 CET