Re: Patch to add support of "IF NOT EXISTS" to others "CREATE" statements

On Sat, Mar 1, 2014 at 7:39 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Fabrízio de Royes Mello <fabriziomello@gmail.com> writes:
> > On Sat, Mar 1, 2014 at 2:11 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> [ re schema upgrade scenarios ]
> >> Why wouldn't COR semantics answer that requirement just as well, if not
> >> better?
>
> > Just because it will replace the object content... and in some cases this
> > cannot happen because it will regress the schema to an old version.
>
> That argument seems awfully darn flimsy. 

> In any case, given the existence of DO it's simple to code up
> create-if-not-exists behavior with a couple lines of plpgsql; that seems
> to me to be a sufficient answer for corner cases.  create-or-replace is
> not equivalently fakable if the system doesn't supply the functionality.
>

You are completely right.

But we already have "DROP ... IF EXISTS", then I think if we would have "CREATE ... IF NOT EXISTS" (the inverse behavior) will be very natural... and I agree in implement "CREATE OR REPLACE" too.

Grettings,

--
Fabrízio de Royes Mello
Consultoria/Coaching PostgreSQL
>> Timbira: http://www.timbira.com.br
>> Blog sobre TI: http://fabriziomello.blogspot.com
>> Perfil Linkedin: http://br.linkedin.com/in/fabriziomello
>> Twitter: http://twitter.com/fabriziomello