Philip Warner <pjw@rhyme.com.au> writes:
> Is there any reason that a security model does not exist for psql that
> allows Unix user 'fred' to log in as PG user 'fred' with no password etc,
> but any user trying to log on as someone other than themselves has to
> provide a password?
Define "log in as themselves" --- in particular, how will you check?
regards, tom lane