Re: Character string relation and functional dependencies

Jan Hidders wrote:
> On 7 dec, 01:24, Tegiri Nenashi <TegiriNena..._at_gmail.com> wrote:

>> On Dec 6, 2:38 pm, Jonathan Leffler <jleff..._at_earthlink.net> wrote:
>>
>>> Tegiri Nenashi wrote:
>>>> On Dec 6, 9:40 am, rp..._at_pcwin518.campus.tue.nl (rpost) wrote:
>>>>> Another difference is that database tables are finite and variable,
>>>> Oh, relations in database world are certainly not restricted by finite
>>>> cardinality.
>>> I thought that computers are finite, so the relations containable in
>>> them are too - even if damn large.  There's a big difference between
>>> very large and infinite.
>> This doesn't really matter. You can still reason about infinite
>> relations with finite resources available on you computer platform.

Because I don't have access to any paid-for resources, I wasn't able to dig deeper than the page indicated, but when I looked at it, it was immediately reminiscent to me of type theory (as opposed to relational theory). Nothing wrong with that of course. However, I think it's important to ask ourselves what it is it that makes sense to implement.

The sense of equality for me has very much to do with one's situation, ie., the application. I can see why some apps might see "overlapping" rectangles, ones that share common vertices if I may use that term, as equal. Also how one might consider different photographs of multiple persons as being the same so far as they might portray the same individual, among others.

When it comes to a system, I've always had the reaction that a facility to define domains/types/objects is quite separate from the Rm, even though any RM implementation must depend on such a facility, whether it is a mental one or a programmed one. Usually, from what I've seen, it is not programmed.

That's about as mystical as I'm prepared to go, outside of a usenet genealogy group. Received on Tue Dec 11 2007 - 06:18:59 CET