Trigger after update not working - sql

Question

I'm struggling to get my 'after update' trigger to work properly.
As seen from my simple query, the sum of the production_work matches the sum of the order elements.
# select ident,ud,dp,swrv,sh,jmsw,sw,prrv,mhsw,bmsw,mp,pr,st,completed from orders;
ident | ud | dp | swrv | sh | jmsw | sw | prrv | mhsw | bmsw | mp | pr | st | completed
-------+----+----+------+----+------+----+------+------+------+----+----+----+-----------
2 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | f
(1 row)
# select * from production_work;
ident | order_id | producer_id | day | ud | dp | swrv | sh | jmsw | sw | prrv | mhsw | bmsw | mp | pr | st
-------+----------+-------------+------------+----+----+------+----+------+----+------+------+------+----+----+----
5 | 2 | 1 | 2013-08-09 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
6 | 2 | 2 | 2013-08-09 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
(2 rows)
I'm trying to set the 'completed' to true if the sum of the work elements match the order element by using this trigger:
CREATE OR REPLACE FUNCTION update_order_completion_status() RETURNS trigger AS
$BODY$
BEGIN
WITH w AS (
SELECT SUM(ud) AS ud, SUM(dp) AS dp, SUM(swrv) AS swrv, SUM(sh) AS sh, SUM(jmsw) AS jmsw, SUM(sw) AS sw, SUM(prrv) AS prrv,
SUM(mhsw) AS mhsw, SUM(bmsw) AS bmsw, SUM(mp) AS mp, SUM(pr) AS pr, SUM(st) AS st
FROM production_work
WHERE order_id = OLD.order_id
), o AS (
SELECT ud, dp, swrv, sh, jmsw, sw, prrv, mhsw, bmsw, mp, pr, st
FROM orders
WHERE ident = OLD.order_id
)
UPDATE orders
SET completed = (w.ud = o.ud AND w.dp = o.dp AND w.swrv = o.swrv AND w.sh = o.sh AND w.jmsw = o.jmsw AND w.sw = o.sw AND
w.prrv = o.prrv AND w.mhsw = o.mhsw AND w.bmsw = o.bmsw AND w.mp = o.mp AND w.pr = o.pr AND w.st = o.st)
WHERE ident = OLD.order_id;
END;
$BODY$ LANGUAGE plpgsql ;
CREATE TRIGGER update_order_completion_status_trigger
AFTER UPDATE OF ud, dp, swrv, sh, jmsw, sw, prrv, mhsw, bmsw, mp, pr, st
ON production_work
FOR EACH ROW EXECUTE PROCEDURE update_order_completion_status();
I'm not getting any error messages when I do the update to the production_work table, but as you can see the completed column is not being set to true.

Answer 1

The SQL query in your trigger func is needlessly complicated and also incorrect (missing FROM clause in UPDATE). A simplified, correct version would be:
UPDATE orders o
SET completed = (w.ud = o.ud AND w.dp = o.dp AND ...)
FROM (
SELECT SUM(ud) AS ud, SUM(dp) AS dp, ...
FROM production_work
WHERE order_id = NEW.order_id
) w
WHERE o.ident = NEW.order_id
AND o.completed <> (w.ud = o.ud AND w.dp = o.dp AND ...);
Assuming completed NOT NULL.
Note, I am using NEW, not OLD, since you want to use the new values.
But if production_work.order_id can change, you'd have to update orders for OLD and NEW.
The last line is to prevent empty updates.
Alternative: VIEW
If you don't need the redundant column completed to optimize performance, I would consider a VIEW instead:
CREATE VIEW order_plus AS
SELECT o.*, (SUM(w.ud) = o.ud AND SUM(w.dp) = o.dp AND ...) AS completed
FROM orders o
JOIN production_work w ON o.ident = w.ident
GROUP BY o.ident;
Assuming ident PRIMARY KEY.