Re: foundations of relational theory? - some references for the truly starving

Mike Preece wrote:

> Costin Cozianu <c_cozianu_at_hotmail.com> wrote in message news:<bn3nbs$seug1$1@ID-152540.news.uni-berlin.de>...
> [snip]
>
>
>>You could compensate if you wanted by a careful thought out scientific
>>work to prove exactly what your model buys the user. Actually, the work
>>was kind of done for you, theorists have analyzed the model and reached
>>the logical conclusion that there's not much to it.
>
>
> References please? Don't bother pointing me to Date's inconclusive
> "research done on the web". I'm more interested in the complete
> analysis with the logical conclusions. I suspect (strongly) that it
> doesn't exist. I concede that there are, however, a vast number of
> theorists that *assume* incorrectly (and illogically) that there's not
> much to it. I'd ask each and every database theorist reading this
> thread to ask themselves "what is the basis in fact for this belief?".
>
>

The basis in facts are very simple: Nested Relations offer no extra expressive power, and plenty of complications.

There is nothing to be had by adding nested relations to the relational model.

Adding nested relations to it it's like adding an operator Y to classical arithmetic a Y b = a + b - a * b, it is totally unnecessary.,

>>Even more, the model
>>is already available one way or the other in existing SQL DBMSes,
>
>
> Yes and no. Yes - the SQL "relational" vendors are slowly coming
> 'round - although the way they implement roughly equivalent capability
> is nowhere near as slick as traditional "Pick". No - because what
> they've come up with ("nested tables") is a "bodge job", very poorly
> implemented, and is therefore rarely used.
>
>

And may we know *exactly* why it is very poorly implemented in your opinion ?

>>but
>>typically I don't use it and most people don't use it, for very
>>practical reasons.
>
>
> Yes. Because "nested tables" is a very poorly done bolt-on.
>
>

Not at all. But because nested tables or however you want to call them are pretty much useless.

>>You can't blame the "theorists"
>
>
> Sure I can - when they make incorrect assumptions, criticise what they
> don't understand, and are prepared to believe others that have done
> likewise.
>
>

Oh, yes, please. The grand conspiracy of database theorists.

>>when you have very practical and serious
>>problems, like for example your clients investing in an obsoleted
>>technology with problematic future. And it is ridiculous for you guys to
>>whine that theorists disregard your model, actually they don't, it's
>>described in all theory books (now that I know it's actually about
>>nested relations), they just are not so crazy about its virtues.
>
>
> Again - references please?

Abiteboul, Hull & Vianu, they are very much neutral on the subject.

> Describe what you know about "nested relations" and
> we'll see.
>

Your attitude is completely idiotic. Are you asking me to prove my competence to you ? Considering how much knowledge you've shown so far, I'd say you're pretty much clueless.

It is you who should give me a good reference -- not marketing idiocies about how "joins are difficult to compute" --, that you consider relevant for showing the difference. And we'll see.

> Regards,
> Mike.

Regards,
Costin Received on Wed Oct 22 2003 - 05:03:24 CEST