Re: Add column if not exists (CINE)

Tom Lane wrote:
> Robert Haas  writes:
> > We can artificially make this problem as complicated as we wish, but
> > the people who are asking for this feature (including me) will, I
> > believe, be quite happy with a solution that throws, say, a NOTICE
> > instead of an ERROR when the object already exists, and then returns
> > without doing anything further.  There are very few, if any,
> > definitional issues here, except by people who are brainstorming crazy
> > alternative behaviors whose actual usefulness I very much doubt.
> 
> > CREATE OR REPLACE is indeed much more complicated.  In fact, for
> > tables, I maintain that you'll need to link with -ldwim to make it
> > work properly.
> 
> This may in fact be an appropriate way to handle the case for tables,
> given the complexity of their definitions.  However, the original
> point of the thread was about what to do for columns.  I still say
> that COR rather than CINE semantics would be appropriate for columns.

I have added this TODO item:
Allow CREATE TABLE to optionally create a table if it does not alreadyexist, without throwing an error    The fact that tables contain data makes this more complex than otherCREATE OR REPLACE operations.        * http://archives.postgresql.org/pgsql-hackers/2010-04/msg01300.php 

--  Bruce Momjian          http://momjian.us EnterpriseDB                             http://enterprisedb.com