> You are correct. nextval() is guaranteed never to give the same number
> (unless setval() were used to reset the sequence value).
Or unless the sequence wraps around. That's less likely (and less
dangerous) than having the OID wrap around, but not impossible.
I personally believe that there is value in a database-generated unique
value like Oracle's ROWID. (Part of what I like about it is that since
it is a system column it simplifies some application issues, since the
app never has to worry about that column unless it chooses to.)
Making the OID sufficiently large to avoid virtually all wraparound
issues would probably mean going to a 64 bit field, which would certainly
be a non-trivial task.
--
Mike Nolan