Re: Truncate if exists - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Truncate if exists
Date
Msg-id 20121012192713.GQ29165@tamriel.snowman.net
Whole thread Raw
In response to Re: Truncate if exists  (Josh Berkus <josh@agliodbs.com>)
List pgsql-hackers
* Josh Berkus (josh@agliodbs.com) wrote:
> On 10/9/12 1:35 PM, Peter Eisentraut wrote:
> > On 10/9/12 5:09 AM, Simon Riggs wrote:
> >> Anyone want to check for any other missing IF EXISTS capability in other DDL?
> >
> > TRUNCATE is not really DDL.  If we allow TRUNCATE IF EXISTS, what is
> > stopping someone from requesting DELETE IF EXISTS or INSERT IF EXISTS next?
>
> That's a very good point.  I tend to think of all utility commands as
> DDL, which of course they're not.

I don't actually see why that's, inherently, a bad idea.  Nor do I see
why IF EXISTS should only apply to DDL and not to all commands.

Obviously, if you write 'IF EXISTS', you've got a plan to deal with the
fact that it doesn't exist.  In a lossy system that's using partitions,
I could actually see a pretty good use-case for wanting INSERT IF
EXISTS (rather than having to constantly poll, waiting for the partition
table that's supposted to be created by some other process to show up).
Thanks,
    Stephen

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