Re: ALTER TABLE ... IF EXISTS feature?

Daniel Farina wrote:
> On Wed, Nov 24, 2010 at 4:30 PM, Bruce Momjian <bruce@momjian.us> wrote:
> > Robert Haas wrote:
> >> With respect to the syntax itself, I have mixed feelings. ?On the one
> >> hand, I'm a big fan of CREATE IF NOT EXISTS and DROP IF EXISTS
> >> precisely because I believe they handle many common cases that people
> >> want in real life without much hullabaloo. ?But, there's clearly some
> >> limit to what can reasonably be done this way. ?At some point, what
> >> you really want is some kind of meta-language where you can write
> >> things like:
> >>
> >> IF EXISTS TABLE t1 THEN
> >> ? ?ALTER TABLE t1 DROP CONSTRAINT IF EXISTS t1_constr;
> >> END IF;
> >
> > FYI, I have felt this way for a while. ?IF EXISTS seemed like something
> > that should never have been added as an inline SQL command option; it
> > just crept in, and kept growing.
> 
> Okay, that being the case: would it make sense to have pg_dump emit DO
> blocks? I have a feeling this might draw fire, but I don't see any
> reason why the mechanism would not work to more or less equivalent
> effect. Certainly making dumps harder to use for those who insist on
> disabling PL/PGSQL is probably a negative side effect, if one can
> identify this hypothetical class of person.

Not being able to recover a dump is serious problem for a user.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +