Re: object algebra

"Christopher Browne" <cbbrowne_at_acm.org> wrote in message news:c1g7eq$1ia96o$3_at_ID-125932.news.uni-berlin.de...
> Oops! "Eric Kaun" <ekaun_at_yahoo.com> was seen spray-painting on a wall:
> > Tables are not relations, and neither of them are "rectangular." You can
> > display, for example, a 4-dimensional tessaract (hypercube) as a table
if
> > you like - that doesn't mean it's rectangular.
>
> You have to be prepared to forgive people at least a little for making
> this mistaken assumption.
>
> After all:
>
> - xBase was often described as a "relational database" despite the
> fact that it certainly wasn't;
>
> - I haven't seen much evidence of commercial SQL system vendors
> having produced systems that are convenient to use with data
> that isn't shaped pretty blindly like a "table."
>
> Perhaps a relational data representation _should_ be analagous to Lisp
> structures or Prolog facts, and therefore be able to be of pretty much
> any shape. But in the absence of conspicuous implementations of such,
> it shouldn't be surprising for people to make the "table" mistake...
> --
> wm(X,Y):-write(X),write('_at_'),write(Y). wm('cbbrowne','ntlug.org').
> http://www3.sympatico.ca/cbbrowne/multiplexor.html
> :FATAL ERROR -- YOU ARE OUT OF VECTOR SPACE
True enough - it's just so commonly used as a slam against relational, as if it's not "multi-dimensional" enough, that it disturbs me when I see it. Somehow the fact that reality is messy bleeds into assumptions that our code and/or data have to be messy too, which is just giving up (and professional malpractice besides).

• Eric