The database coordinator doesn't write triggers - just filters.
For example, the coordinator in the Dean's office might want to allow Department heads in Pathology and Pediatrics to view those faculty that have appointments in both departments (all departments share the same database).
So she'd write a filter on the demographic table selecting those faculty belonging to both departments, set up a new role, assign it to that filter, and then add that role to the roles each Department head already has.
The fixed triggers do all the rest. So if someone is no longer a member of both departments, or the filter is replaced with another one that just selects recent appointments to both departments, then the two department heads will see different people when they log in again.
Only single-record changes are triggered, because only single-record changes are made by the users (eg. adding new person, changing existing address, etc.).