Re: infinite result sets?

graeme_at_inorbit.com (Graeme Newlands) wrote in message news:<aecd37bf.0402140841.49e8a115_at_posting.google.com>...
> Just a random thought over the weekend ...
>
> Is there any join operation that could possibly return an infinite
> result set in set theory?
>
> Is this operation definable in SQL?
>
> Graeme Newlands.

Hello Graeme,

Still thinking nice abstruse thoughts then :)

An interesting question; my first thought was "why not", but I'm not sure whether they're expressible in anything at the moment; usually inifinite data structures are described by an expression rather than an enumeration of values, and the expression is evaluated as far as is needed for any given computation. Relational calculus could do it, I think, but I don't know about whether it's been tried with the relational algebra. Hints on reading for this, anyone ? (Maybe some of the papers on the universal relation might have some pointers ?)

SQL is a bit of a no-no for this kind of "interesting" question (it raises its own "interesting" questions instead).

• Tony