Re: [PATCHES] Updatable views

--On Donnerstag, August 31, 2006 11:10:47 -0400 Tom Lane 
<tgl@sss.pgh.pa.us> wrote:

> The problem is not with the view condition.  Consider
>
>     CREATE TABLE data (id serial primary key, ...);
>
>     CREATE VIEW only_new_data AS SELECT * FROM data WHERE id > 12345
>         WITH CHECK OPTION;
>
>     INSERT INTO only_new_data VALUES(nextval('data_id_seq'), ...);
>
> The proposed implementation will execute nextval twice (bad), and will
> apply the WITH CHECK OPTION test to the value that isn't the one stored
> (much worse).  It doesn't help if the id is defaulted.

*scratches head*....i don't see a shortcoming solution for this in my 
current implementation,
indeed. I admit that this is a serious containment of updatable views in 
its current
incarnation (at least for the check option).

*thinking*
I would like to try to grab your idea to push down the CHECK OPTION logic 
down to the executor as a (table/view?) constraint. Would that be an idea 
worth to consider and,
most important, is this doable? I don't have that much experience in the 
executor, so i fear
this isn't something that will be done within a week or so.....:(

--  Thanks
                   Bernd