[SOLVED] Re: A question about trigger fucntion syntax

On Sun, Aug 11, 2019 at 05:31:13PM -0400, stan wrote:
> I trimmed this thread quite a bit.
>
> Thanks to the help I have received, I am making progress. I have looked a the
> recommended documentation, and I believe I am close. I have utilized the
> "debugging printf" capability here. Here is where I am. I have the following
> function create.
>
>
> DROP TRIGGER validate_task_trig ON task_instance ;
>
> DROP FUNCTION check_permission() ;
>
>
> CREATE FUNCTION check_permission()
> RETURNS trigger AS $$
> DECLARE _permit boolean;
> BEGIN
> SELECT
> permit INTO _permit
> FROM
> permitted_work
> WHERE
> NEW.employee_key = OLD.employee_key
> AND
> NEW.work_type_key = OLD.work_type_key;
> RAISE NOTICE 'New employee_id % NEW.work_type_key % _permit = %',
> NEW.employee_key ,
> NEW.work_type_key ,
> _permit ;
> if NOT _permit THEN
> RAISE NOTICE 'No permission record';
> RAISE EXCEPTION 'No permission record';
> ELSE
> RAISE NOTICE 'Found Permission Record';
> END IF;
> if _permit = FALSE THEN
> RAISE NOTICE 'Permission Denied';
> ELSE
> RAISE NOTICE 'Permission Granted';
> END IF;
>
> return NEW;
> END;
> $$
> LANGUAGE PLPGSQL;
>
> CREATE TRIGGER validate_task_trig BEFORE INSERT OR UPDATE ON task_instance
> FOR EACH ROW EXECUTE FUNCTION check_permission();
>
>
> Now the issues, currently seems to be that nothing is getting assigned to
> _permit. Here is the output of a run with 0 records in the permitted_work
> table.
>
> NOTICE: New employee_id 1 NEW.work_type_key 8 _permit = <NULL>
> NOTICE: Found Permission Record
> NOTICE: Permission Granted
> INSERT 0 1
>
> so it appears that nothing is getting assigned to _permit. Also should I be
> checking for _permit as NOT NULL in the first if clause?
>
> Thanks for all the had holding on this. Brand new application for me.

For the archive.

I have this working, Here is the function that I woulnd up with.

DROP TRIGGER validate_task_trig ON task_instance ;

DROP FUNCTION check_permission() ;

CREATE FUNCTION check_permission()
RETURNS trigger AS $$
DECLARE _permit boolean;
BEGIN
SELECT
permit INTO _permit
FROM
permitted_work
WHERE
NEW.employee_key = permitted_work.employee_key
AND
NEW.work_type_key = permitted_work.work_type_key;
if _permit IS NULL THEN
RAISE EXCEPTION 'No permission record';
ELSE
END IF;
if _permit = FALSE THEN
RAISE EXCEPTION 'Permisson Denied';
END IF;

return NEW;
END;
$$
LANGUAGE PLPGSQL;

CREATE TRIGGER validate_task_trig BEFORE INSERT OR UPDATE ON task_instance
FOR EACH ROW EXECUTE FUNCTION check_permission();

Thanks to all the people that were instrumental in helping me learn
triggers and functions.

--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin