Re: Help with array constraints

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Nigel J. Andrews
> Sent: Thursday, April 03, 2003 11:19 AM
> To: Jason Hihn
> Cc: Richard Huxton; pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Help with array constraints
>
>
> On Thu, 3 Apr 2003, Jason Hihn wrote:
> You probably want to write your own function(s) and install it(them) as
> trigger(s).
>
> create function letter_fk () returns trigger as '
> declare
>     ind    integer;
> begin
>     for ind in array_dims(NEW.letters) loop
>         perform 1 from _test where id = NEW.letters[ind];
>         if not found then
>             raise exception ''My foriegn key constraint
> violation'';
>         end if;
>     end loop;
>
>     return NEW;
> end;
> ' as language 'plpgsql';
>
> create trigger my_array_fkey
>  before insert
>  on test
>  for each row execute procedure letter_fk();
>
>
> Or something like that anyway. Also that's only a start.

Ah that's more like what I'm looking for. I have to attempt a select of the
new letter in the contrainted-to table. If it finds it, success! If the
contrainted-to table has an index, it should be very fast no matter how many
letters it's being constrained against...
"SELECT NEW.letter FROM constraint_table WHERE letter=id"
if null set raise exception.

I would have thought this would be built in? Can it be?