Listing Triggers corresponding to foreign keys

Hi all,

Am I right in saying that when you add a constraint to a table it just
produces three triggers?  If so which triggers?

There seems to be no easy way of listing triggers (or rules).  I assumed
there was something like \d? which would do the job but could find nothing
in the docs.  I can find a list in pg_trigger but am not sure of the
details.

BTW are there any docs for each of the system tables as there seems to be no
other way to certain things than dive into these and work what each does!!

It says in the docs to drop constraints on a table you drop the table and
remake it, but I only want to drop one of the constraints, do I just have to
drop the triggers (When I have found out which ones) or drop and remake the
table and then remake the other constraints.

Any help would be appreciated.

Ben