Re: Partial update on an postgres upsert violates constraint

On 11/21/2016 02:32 AM, Andreas Terrius wrote:
> Is there any way to check whether the row already exists before checking
> constraints ? I still want it to fail if it turns out to be a new row
> (which would violate the not null constraint), but updates the row if it
> already exists.
>
> Since if that is not possible, I would need to do a query to determine
> whether the row exists in the database which kinda eliminates the use of
> upsert. (in this case, partial upsert).

Before UPSERT appeared in 9.5, folks came up of with alternate methods
of doing this. I would suggest searching on:

postgres upsert cte


You might be able to modify the examples to get what you want.

>
>
>
> On Sun, Nov 20, 2016 at 3:57 AM, Tom Lane <tgl@sss.pgh.pa.us
> <mailto:tgl@sss.pgh.pa.us>> wrote:
>
>     Adrian Klaver <adrian.klaver@aklaver.com
>     <mailto:adrian.klaver@aklaver.com>> writes:
>     > ... So looks like constraints are checked before you get to the ON
>     CONFLICT section.
>
>     Right.  ON CONFLICT is a means for dealing with duplicate-key errors in
>     the specified (or inferred) unique index.  It is *not* an all-purpose
>     error catcher.  In the case at hand, the given INSERT request fails due
>     to not-null constraints that are unrelated to what the ON CONFLICT
>     clause
>     tests for.
>
>                             regards, tom lane
>
>


--
Adrian Klaver
adrian.klaver@aklaver.com