Re: Add column if not exists (CINE)

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andrew Dunstan <andrew@dunslane.net>, Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>, Kjell Rune Skaaraas <kjella79@yahoo.no>, pgsql-hackers@postgresql.org
Date: 2010-04-28T16:31:09Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> Actually, that's a good idea.  But how will you handle tables?

Well, tables are a special case, mainly because it's not clear how to
avoid accidentally throwing away data.  (In particular if some column in
the existing table isn't there in the new definition.  It's a bit scary
to just drop the column, IMO.)  I don't see that that argument applies
to doing an automatic ALTER COLUMN, though, especially since the only
column type alterations that will go through without a USING clause are
reasonably straightforward.

			regards, tom lane