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

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.

- Heikki