Re: In an RDBMS, what does "Data" mean?

"Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message news:LnpFiHNqXPxAFwgC_at_thewolery.demon.co.uk...
> In message <kH4wc.5267$n65.660_at_newssvr33.news.prodigy.com>, Eric Kaun
> <ekaun_at_yahoo.com> writes
> Relational is more egalitarian about what you can ask (actually, I'm not
> sure about that, but never mind ...)
>
> But it's like being "politically correct". Sure, you may want to know
> "how many blokes have a car the same colour as their wife's hair?".
>
> BUT! Do you want to make "all questions equally easy to answer" or do
> you want to make "common questions easier to answer than unusual ones".
> If by levelling off the ease of asking questions, you simply make the
> easier questions harder in order to level the playing field, you're
> doing your users a very big disservice. Is that what you're trying to
> achieve?

Not at all. I want a firm logical foundation for any questions, and to have that foundation serve as the basis for making questions easier to answer - in other words, to define useful (though necessarily restricted) views in terms of an egalitatian model. Otherwise my initial choice is simply too risky, at least in complex domains.

> And with a little bit of thought, you can make nearly ANY question in
> Pick easy to answer. More to the point, you can PROVE that the system
> can answer the question easily.

Please elaborate on both of these. I have no idea what proving something easy to answer entails...

> Given that relational goes to extreme
> lengths to separate the logical from the physical,

? Extreme lengths to separate? I'd say is simply tries to keep them "naturally" separate, though of course I have no definition for "natural". :-)

> relational actually
> prevents you from even trying to prove the question is easy, merely
> saying "you have no choice but to trust the optimiser" :-(

Huh? Prove the question is easy? What does that mean?

At any level above hardware, we have no choice - it depends on the processor, and hard disk, and memory speed, and... so of course there's a level of trust involved. Do you trust the Pick compiler / interpreter? I certainly want to delegate the nasty business of optimization (which we've demonstrated is useful in the considerably more-difficult area of compilers) to a machine which can do the job better and faster than I.

• erk