Re: Queries across multiple databases (was: SELECT from a table in another database).

On Monday 21 May 2001 10:04am, you wrote:
> On Mon, 21 May 2001 07:55:13 -0400
>
> Andrew Rawnsley <ronz@ravensfield.com> wrote:
> > If I ever come up with said schema-dropping patch, and anyone else
>
> wants it,
>
> > let me know.
>
> I'd dance a happy jig ;-)
>
> I'm not sure whether it is quite the way to do it, but I'd have a better
> time with things if I could span databases in a single request. Are
> there theoretical problems with spanning databases in a single query? Is
> it a feature of bad database design & implementation?
>

I imagine its one of those initial implementation decisions made 12 years ago
by people completely separate from the current maintainers, to whom this sort
of need wasn't a priority. I would also hazard to guess (in near-complete
ignorance - correct me if I'm wrong) that it would be difficult to change
without doing serious re-plumbing. Hence its 'exotic' status. The current set
of maintainers certainly have enough to think about without slamming them
with that sort of change...

I do think the issue will continue to bubble to the top as more and more folk
get stuck into the position of wanting to transition to Postgres from
Oracle/Sybase/whatever and either don't want to recode or simply can't, and
also want to maintain as much database neutrality as possible.

The 'drop the schema' thing isn't quite the way to do it, no. Its a gross
hack, but if it gets us through until it becomes a more important issue then
so be it. Hence the sense of getting the source... (or, as I have heard Paul
Everitt say, you can actually fix the problem after hundreds of manhours as
opposed to just being told that your support level isn't high enough).


--
Regards,

Andrew Rawnsley
Ravensfield Geographic Resources, Ltd.
(740) 587-0114
www.ravensfield.com