On Tue, Apr 27, 2010 at 6:45 PM, Kjell Rune Skaaraas <kjell...@yahoo.no> wrote: > Hello, > > I've been reading the earlier threads at: > http://archives.postgresql.org/pgsql-hackers/2009-05/thrd7.php#00252 > http://archives.postgresql.org/pgsql-hackers/2005-10/thrd4.php#00632 > and I'm not sure I have anything that substantially new to add but: > > 1. I can't see there's an unambiguity about what the syntax would do. It is > IF NOT EXISTS, not IF NOT LIKE. Anyone who shoots themselves in the foot by > calling a CINE and thinking that a preexisting differently defined column is > magically converted deserves it. Either it should act exactly like the > non-CINE command, or do nothing at all as if the statement wasn't there. > > 2. The use case is pretty clear to me - flexible scripts that'll bring all > earlier database versions to the latest schema. I've been experimenting in > 9.0 alpha with calling DROP CONSTRAINT IF EXISTS then ADD CONSTRAINT with > named constants for a CINE effect. which as a side effect will correct any > updated constraints too - and it works great. Unfortunately DROP COLUMN IF > EXISTS then ADD COLUMN has the side effect of deleting all the data, so > that's hardly usable. > > I saw some indications that this might be a minority opinion, well I would > like to cast a vote FOR this functionality. The workarounds are ugly, the > solution simple and while I agree it's possible to misuse it, my opinion is > that you shouldn't become a surgeon if you can't handle a scalpel. In this > case I get the feeling I'm reading instructions on how to do surgery with a > butter knife because we don't dare hand out anything sharper.
I've already said my piece on this, but I couldn't agree more. Well said, and your use case is exactly the one I want it for. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
