Re: Inspecting a DB - psql or system tables ?

On Fri, May 27, 2011 at 08:26:33PM +0200, Tomas Vondra wrote:
> > While parsing the output of psql is cumbersome, accessing the
> > system tables seems more likely to break whenever a new version
> > of PostgreSQL comes out.
>
> Really? Those catalogs are pretty stable, and when changed they're
> usually extended (new columns are added). So well written queries won't
> break very often. Actually I'd expect the psql output to change much
> more often.

The whole point of the information_schema is that it's well-defined by
the standard.  The system tables themselves do sometimes change
between versions -- that's why you get warnings from psql when you
start up a client with a different major version number than the
server.  (If you want to see this in action, try using a 7.4-era
client with 9.0, and do some tab completion or something like that.)

A

--
Andrew Sullivan
ajs@crankycanuck.ca