[eluser]WanWizard[/eluser]
Code:
// mark this alarm as fired
$alarm->set_join_field($user, 'wasfired', TRUE);
// mark all alarms related to users as fired
$alarm->set_join_field('user', 'wasfired', TRUE);
You only need the "relationship key" instead of the model name if you have the defined the relationship as advanced, and used a custom name for the relation.
If this doesn't work, what is the result of $alarm->check_last_query()?