Re: foundations of relational theory?

In article <_Qymb.25414$Fm2.10043_at_attbi_s04>, Marshall Spight <mspight_at_dnai.com> writes
>"Bob Badour" <bbadour_at_golden.net> wrote in message news:HPudnfvbBOkx4weiU-
>KYhw_at_golden.net...
>> "Marshall Spight" <mspight_at_dnai.com> wrote in message
>> news:MDomb.23527$HS4.91636_at_attbi_s01...
>>
>> > One thing this thread has gotten me thinking about is the agility
>> question.
>>
>> Agility is just another word for logical independence. Pick lacks it.
>
>Well, okay. But do existing DBMSs have complete logical independence?
>I think they don't. Views aren't as easy to work with as they need to
>be, for example.
>
>
>> [lots of "you can use" statements snipped]
>>
>> > Relations look like the clear winner to me.
>>
>> One might use some as yet unidentified structure. Dawn wants to contribute
>> something as important as any contribution by Aristotle, Boole or Goedel.
>> She is welcome to try.
>
>Indeed. I don't expect her, or anyone else for that matter, to make
>such a discovery. But that doesn't mean the exercise is without
>value. For example, Dawn has criticized the fact that in current
>practice, it may takes some time for an application programmer
>to get a DBA to make a needed schema change. This is a very
>real issue that affects me regularly; I'm interested to hear her
>take on the issue. Maybe she has useful ideas that will make
>this less of a problem.

Sack the DBA :-) Pick databases very rarely have a dba looking after them.
>
>Of course, this issue is one of practice and not one of
>foundations, but that's okay. If someone solves this issue
>while mistakenly believing it to be a foundational issue,
>it is still solved.
>
>Although I don't believe Dawn will invent a new logical
>structure, I could imagine she might come up with something
>interesting about schema change management. And even
>if she doesn't, that will help me understand the degree of
>hardness of the problem, and the degree to which the
>problem is fundamental.
>
>From her and others' posts, it sounds like Pick makes
>schema change management easy. I'd like to understand
>why: does it come at a cost of expressiveness, is it
>a well-designed tool, what?

Well, imagine using a SQL table to define another SQL table. (Actually, I think that's a relational requirement, although every relational db I've met has hidden that fact very well). In MV, the FILE definition is just a FILE like any other :-) We just edit the DICT FILE.
>
>Consider: the fact that Microsoft Access has a crappy
>unscalable SQL engine as its core doesn't change the
>fact that it has some pretty cool RAD tools.
>
Cheers,
Wol

-- 
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
Witches are curious by definition and inquisitive by nature. She moved in. "Let 
me through. I'm a nosey person.", she said, employing both elbows.
Maskerade : (c) 1995 Terry Pratchett