Re: Objects and Relations

From: David BL <davidbl_at_iinet.net.au>
Date: 24 Feb 2007 00:13:10 -0800
Message-ID: <1172304790.186193.63060_at_k78g2000cwa.googlegroups.com>


On Feb 24, 4:17 pm, "Marshall" <marshall.spi..._at_gmail.com> wrote:
> On Feb 23, 10:16 pm, "David BL" <davi..._at_iinet.net.au> wrote:
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> > On Feb 24, 12:12 pm, "Marshall" <marshall.spi..._at_gmail.com> wrote:
> > > On Feb 23, 6:40 pm, "David BL" <davi..._at_iinet.net.au> wrote:
>
> > > > You did not realise my point? I'm talking about representing these
> > > > things and processing these things, and not merely stating facts
> > > > *about* these things. My whole point has been that RM is perfect for
> > > > the latter but not so good for the former. If you agree with that
> > > > then please say so.
>
> > > I don't, and as near as I can tell no one else here does either.
>
> > > > If you think RM is suitable for scenegraphs I would be particularly
> > > > interested.
>
> > > That is a strange way to think about it. On the one hand you have
> > > a collection type and on the other hand you have application level
> > > constructs. Let's invert it:
>
> > > If you think hashtables are suitable for payroll I would
> > > be particularly interested.
>
> > > Doesn't make much sense.
>
> > > (Note that this is *structurally* similar to what you wrote,
> > > but not semantically similar.)
>
> > I'm not interested in metaphorical argument.
>
> That's funny that you would say that, because I view what you
> are saying as entirely metaphorical. Actually maybe metaphysical
> would be closer. In any event I was pointing out that you were
> comparing things from different domains, and that that isn't
> productive here.

I don't understand. I wasn't comparing RM and scenegraphs. I was talking about whether RM is suitable to be *applied* in that domain.

> > I'm aware of half a dozen scenegraph frameworks and none use the
> > relational approach. Often scenegraph nodes are Java or C++ objects [...]
>
> Java and C++ don't have relational operations, neither in the language
> nor in the libraries. Absence of evidence is not evidence of absence.

I'm well aware that your opinion (or conjecture if you like) that RM is suitable depends on a language and compiler that doesn't currently exist. I don't hold that against you!

On another note, I'm interested in your opinion on my last post to Jim about the use of a strings relation. I know you've already talked about using RVAs. Anyway, it concerns the fact that a relation is meant to represent an extension of some well defined type (do you agree), yet a strings relation would only contain a hodge-podge of strings, ie used for attributes elsewhere in the database. That makes it quite suspicious, don't you agree? It could be argued that the only respectable relation for strings would contain all possible strings and be infinite. Received on Sat Feb 24 2007 - 09:13:10 CET

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