On 3/29/17, Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote:
> On 3/24/17 05:29, Vitaly Burovoy wrote:
>> It would be great if "DROP IDENTITY IF EXISTS" is in the current patch
>> since we don't have any disagreements about "DROP IDENTITY" behavior
>> and easiness of implementation of "IF EXISTS" there.
>
> Here is an updated patch that adds DROP IDENTITY IF EXISTS.
>
> Unfortunately, implementing ADD IF NOT EXISTS is much harder, so I
> haven't done that here.
>
> Additionally, this patch fixes a few minor issues that you had pointed
> out, and merges with the new expression evaluation system in the executor.
>
> I have also CC'ed you on a separate patch to improve the behavior when
> changing a sequence's data type.
Thank you a lot. I'll have a deep look by the Sunday evening.
Why do you still want to leave "ADD IF NOT EXISTS" instead of using
"SET IF NOT EXISTS"?
If someone wants to follow the standard he can simply not to use "IF
NOT EXISTS" at all. Without it error should be raised.
But we would not need to introduce a new grammar for a column property
which is single and can't be added more than once.
--
Best regards,
Vitaly Burovoy