Null asks:
> Would you elaborate on the alternatives that you see to cross-db queries?
>
> Are you saying that it would better to duplicate the same data in several
> databases or put everything in one huge database or what ...?
>
> "Jan Wieck" <JanWieck@Yahoo.com> wrote in message
> news:200108271655.f7RGtG307375@jupiter.us.greatbridge.com...
> > IMNSVHO the biggest argument against cross-DB queries is this
> > useless extensibility in PostgreSQL. As soon as someone
> > creates a data type, operator, aggregate or function, things
> > get complicated. Have a data type "acctno" defined in both
> > databases. And yes, we have operators for equalness in both
> > DB's too. Now we do a cross-DB join and have two "acctno"s
> > in the WHERE clause.
> >
> > First off, all these objects will have different OID's in the
> > two system catalogs. Next, how do you know if the two types
> > will at least have a similar external representation? And
> > which of the two "=" operator functions will get called?
> >
> >
> > Jan
Really the type isn't just acctno but dbname.acctno
Operators could work by converting both types to some base type
that 'both databases understand'.
Cheers,
Colin