Re: Add column if not exists (CINE)

Tom Lane wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> 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 already
exist, without throwing an error

The fact that tables contain data makes this more complex than other
CREATE OR REPLACE operations.

* http://archives.postgresql.org/pgsql-hackers/2010-04/msg01300.php

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com