Re: [v9.3] writable foreign tables

2012/8/28 David Fetter <david@fetter.org>:
> On Tue, Aug 28, 2012 at 10:58:25AM -0400, Tom Lane wrote:
>> Kohei KaiGai <kaigai@kaigai.gr.jp> writes:
>> > It seems to me TargetEntry of the parse tree can inform us which column
>> > should be modified on UPDATE or INSERT. If it has just a Var element
>> > that reference original table as-is, it means here is no change.
>>
>> Only if you're not going to support BEFORE triggers modifying the row...
>
> +1 for supporting these.
>
> Speaking of triggers on foreign tables, what's needed to support them
> independent of support at the FDW level for writing on foreign tables,
> or does that even make sense?
>
I agree with trigger support on foreign tables is definitely useful feature,
even though it does not have capability to replace the writable foreign
table functionality.

In case when foreign-table definition does not contain a column mapped
with primary-key column in remote-side, the trigger function cannot
determine which row should be updated / deleted.
It is a situation that FDW driver should track a particular remote-row using
its identifier.

Thanks,
-- 
KaiGai Kohei <kaigai@kaigai.gr.jp>