On 9/28/05, Tom Lane <[EMAIL PROTECTED]> wrote:
> Ian Meyer <[EMAIL PROTECTED]> writes:
> >   IF TG_OP = 'DELETE' AND OLD.deleted = FALSE THEN
>
> > ERROR:  record "old" is not assigned yet
> > DETAIL:  The tuple structure of a not-yet-assigned record is indeterminate.
> > CONTEXT:  PL/pgSQL function "thread_sync" line 2 at if
>
> > What am I failing to understand with this?
>
> We don't guarantee short-circuit evaluation of boolean expressions.
> You'll have to break that into two IFs, ie,
>
>         IF TG_OP = 'DELETE' THEN
>                 IF ... test on OLD.something ...
>
>                         regards, tom lane
>

Ah ha.. that makes sense. I fixed it to be:

CREATE OR REPLACE FUNCTION thread_sync() RETURNS trigger AS $$
BEGIN
  IF TG_OP = 'DELETE' THEN
    UPDATE member SET total_threads=total_threads-1 WHERE id=OLD.member_id;
    RETURN OLD;
  ELSEIF TG_OP = 'INSERT' THEN
    UPDATE member SET total_threads=total_threads+1 WHERE id=NEW.member_id;
    RETURN NEW;
  ELSEIF TG_OP = 'UPDATE' THEN
    IF NEW.deleted != OLD.deleted THEN
      IF NEW.deleted = TRUE THEN
        UPDATE member SET total_threads=total_threads-1 WHERE id=NEW.member_id;
        RETURN NEW;
      ELSEIF NEW.deleted = FALSE then
        UPDATE member SET total_threads=total_threads+1 WHERE id=NEW.member_id;
        RETURN NEW;
      END IF;
      RETURN NULL;
    END IF;
    RETURN NULL;
  END IF;
END;
$$ LANGUAGE plpgsql;

Here's my next question(s)... If i have 2 rows in the thread table and
I delete 1 of the rows with: delete from thread where id=26; it ends
up decrementing the total_threads value by 2, instead of one.

bcodev=> select id, total_threads from member;
 id | total_threads
----+---------------
  1 |             2
(1 row)

bcodev=> delete from thread where id=37;
DELETE 1
bcodev=> select id, total_threads from member;
 id | total_threads
----+---------------
  1 |             0
(1 row)

I'm confused, to say the least.

Thanks for all the help.

Ian

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