Let's say I have the following contrived schema:
TRANSPORTATION_MODE
mode_ID serial
model_number text
AIRPLANE
mode_ID int FK
operational_ceiling nt
AUTOMOBILE
mode_ID int FK
cruising range int
Of course, being an airplane and being an automobile are mutually exclusive.
How does one program the mutual exclusivity in PostgreSQL? I've studied using
check contraints, triggers, and rules, but I'm not finding any obvious way to
program this.
