lib/que/scheduler/migrations/7/up.sql
CREATE OR REPLACE FUNCTION que_scheduler_prevent_job_deletion() RETURNS TRIGGER AS
$BODY$
DECLARE
BEGIN
IF OLD.job_class = 'Que::Scheduler::SchedulerJob' THEN
IF NOT que_scheduler_check_job_exists() THEN
raise exception 'Deletion of que_scheduler job prevented. Deleting the que_scheduler job is almost certainly a mistake.';
END IF;
END IF;
RETURN OLD;
END;
$BODY$
LANGUAGE 'plpgsql';