Re: Network Example: Sibling of Opposite Gender

On Dec 30, 10:51 am, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
> Check out some of the articles at:
>
> http://www.thethirdmanifesto.com/
>
> In particular, try:http://www.dcs.warwick.ac.uk/~hugh/TTM/Missing-info-without-nulls.pdf

Well, as much as I respect Mr. Darwen, (Dr. Darwen?) I don't find this paper
particularly compelling. While it certainly addresses the semantic issues well,
it doesn't show us much about how we're going to do queries, and it doesn't
particularly justify what appears to be added complexity in updates.

And as near as I can tell, his solution goes to a great deal of trouble simply to
emulated tagged unions in a relational language without them. It would be
ever so much simpler just to say, let our relational language support tagged
unions.

http://en.wikipedia.org/wiki/Tagged_union

(Amusingly, I expect that a particularly nice implementation of tagged unions
in a relational language would bear a distinct resemblance to the logical
representation in that paper. However that doesn't mean I want that to be the logical interface that I have to work with.)

I would be interested in a discussion about how this all should work in regards to aggregate functions. I would particularly be interested in a discussion about how all these same issues interact with nested relations, and aggregates on same.

It's all very complicated. I tried writing up my current understanding of these issues and comparing various solutions to them, but it got rather bogged down. I must resurrect that effort at some point.

Marshall Received on Sat Dec 30 2006 - 20:23:57 CET