Re: Patch to add support of "IF NOT EXISTS" to others "CREATE" statements - Mailing list pgsql-hackers

From Fabrízio de Royes Mello
Subject Re: Patch to add support of "IF NOT EXISTS" to others "CREATE" statements
Date
Msg-id CAFcNs+rDg6pLRP0gc-BNb2h3z_KJYC06B848rjf8Qoz-An1B=Q@mail.gmail.com
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In response to Re: Patch to add support of "IF NOT EXISTS" to others "CREATE" statements  (Heikki Linnakangas <hlinnakangas@vmware.com>)
List pgsql-hackers

On Tue, Aug 26, 2014 at 10:20 AM, Heikki Linnakangas <hlinnakangas@vmware.com> wrote:
On 04/14/2014 10:31 PM, Fabrízio de Royes Mello wrote:
On Tue, Apr 1, 2014 at 2:46 PM, Robert Haas <robertmhaas@gmail.com> wrote:

Where this is a bit more interesting is in the case of sequences, where
resetting the sequence to zero may cause further inserts into an
existing table to fail.

Yeah.  Sequences do have contained data, which makes COR harder to
define
--- that's part of the reason why we have CINE not COR for tables, and
maybe we have to do the same for sequences.  The point being exactly
that if you use CINE, you're implicitly accepting that you don't know
the ensuing state fully.

Yeah.  I think CINE is more sensible than COR for sequences, for
precisely the reason that they do have contained data (even if it's
basically only one value).


The attached patch contains CINE for sequences.

I just strip this code from the patch rejected before.

Committed with minor changes:

* The documentation promised too much. It said that it would not throw an error "if a sequence with the same name exists". In fact, it will not throw an error if any relation with the same name exists. I rewrote that paragraph to emphasize that more, re-using the phrases from the CREATE TABLE manual page.

* don't call RangeVarGetAndCheckCreationNamespace unnecessarily when IF NOT EXISTS is not used.


Thanks!


--
Fabrízio de Royes Mello
Consultoria/Coaching PostgreSQL

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