Re: Expressions versus the value they represent
Date: Mon, 12 Apr 2010 14:51:07 -0300
Message-ID: <4bc35d8e$0$12426$9a566e8b_at_news.aliant.net>
Keith H Duggar wrote:
> On Apr 12, 7:09 am, David BL <davi..._at_iinet.net.au> wrote:
>
>>On Apr 12, 2:37 pm, Keith H Duggar <dug..._at_alum.mit.edu> wrote:
>>
>>>Hopefully we can agree that since there is no interpretation defined
>>>in the RM nor FOL that there are not "multiple phases" nor "playing
>>>around" nor any other of the problems above.
>>
>>Yes I agree with that, but I actually want to consider the problems
>>that arise under interpretations.
>
> Ok, cool. Thanks for this and the other clarifications. Now I'm
> a bit clearer on understanding what you are exploring. However,
> are we agreed that in the context of RM this is what we would
> call the "physical" layer?
>
> For example, suppose that we define a particular interpretation
> that maps the ellipse and circle terms to particular structures
> say sets over which we define various other axioms (perhaps even
> including axioms referring to natural (as in physical world)
> observations. Then I would argue that even though these sets
> are not bits and bytes they are, none-the-less, "physical" in
> so far as the RM is concerned. Would you agree?
Are you conflating physical and conceptual?
<snip>
>>>Anyhow, interpretation is >>>orthogonal and therefore irrelevant to both FOL and RM. >> >>I agree. However I consider the topic of my post to concern the >>problem of how to encode values on a computer, in which case a formal >>semantics is required.
>
> Got it.
>
>
>>Perhaps it would be worth discussing whether that is a fundamental >>requirement in database theory? I consider "data" to mean "encoded >>value".
Data means information represented suitably for mechanical processing. The information might be a value or might be something else. The data might encode information originating in a different form, or it may originate in a suitable representation.
Database theory at the conceptual and logical levels of discourse requires no computer. While the primary application of database theory is to record information on physical devices and while the vast majority of such devices involve digital electronics, those devices need have nothing to do with digital electronics. e.g. a card catalog
> Hmm ... interesting question. I'm guessing, and this truly is
> a guess, that in the larger context of "database theory" the
> answer is yes. In the smaller context of "relational model"
> the answer is no. I hope one of the "regulars" will correct
> and expound on this.
I think the correct answer in both cases is "sometimes". Received on Mon Apr 12 2010 - 19:51:07 CEST