Tim Wilson <wilson@isis.visi.com> writes:
> I'm having trouble understanding when to use table constraints vs.
> column ones.
There's no functional difference --- if you have a constraint that only
involves one column, you can write it either way. Do what seems easier
to understand.
I believe pg_dump will dump all constraints as table constraints, so in
the long run it may not make any difference anyway ;-)
regards, tom lane