Re: One-To-One Relationships
Date: Fri, 30 Nov 2007 00:03:46 -0400
Message-ID: <474f8ba3$0$5284$9a566e8b_at_news.aliant.net>
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.