Re: RA with MV attributes
Date: Wed, 17 Jan 2007 14:58:11 GMT
Message-ID: <7Qqrh.691473$R63.173281_at_pd7urf1no>
David wrote:
> paul c wrote:
>
>>David wrote: >> >> >>>... >>>Why can't we say that *by definition* the set of attributes of a >>>relation is part of its state not its type? >>>... >> >>We can say anything we want "by definition", the question is where does >>saying it get us? What conclusions does it lead to and so forth.
>
>
> Marshall doesn't seem prepared to accept this definition on it face,
> because he has assumed that the set of attributes of a relation is
> surely its type.
>
>
>>I >>like your suggestions because they seem to have something behind them, >>but don't ask me what, exactly. I wish you would distinguish whether >>you are talking about physical implementations or user concepts.
>
>
> I guess this relates to the following discussion
>
> http://www.ai.mit.edu/docs/articles/good-news/subsection3.2.1.html
>
> I tend to think that both implementation and interface should be
> reasonably simple, and it's bad to strongly favor one at the expense of
> the other. I often look at what the implementation is telling me in
> order to design a reasonable interface. There is nothing better than
> getting your cake and eating it too.
>
That's a bit too blurry for me. What is simple as compared to what is too simple depends very much on the objective, as I think somebody said "as simple as possible, but no simpler!".
I do think that once one has a definition it is important to proceed to positioning it in the scheme of things, for example is this a physical approach for storing two relations in one or is it an attempt to promote three-valued logic or is it something else? I find this thread interesting because I think rva's have not been explored very thoroughly (perhaps they should be discounted eventually, but I don't think anybody has yet made a good case, or at least one I could understand, for this, yet).
p Received on Wed Jan 17 2007 - 15:58:11 CET