ok, got it.
thanks for the clarification and the hand holding.
-Whit
On Mon, Apr 27, 2009 at 1:09 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Whit Armstrong <armstrong.whit@gmail.com> writes:
>> Am I misinterpreting this documentation? Are there cases in which the
>> OID's of two tables will collide? I don't see any uniqueness
>> constraints on the pg_class table.
>
> You didn't look too hard:
>
> regression=# \d pg_class
> ...
> Indexes:
> "pg_class_oid_index" UNIQUE, btree (oid)
> "pg_class_relname_nsp_index" UNIQUE, btree (relname, relnamespace)
>
> All system catalogs that have OIDs at all effectively treat them as a
> primary key. If they weren't unique identifiers they wouldn't be good
> for much ...
>
> What the documentation is trying to point out is that the uniqueness
> guarantees don't extend across tables. So for example a table and a
> datatype could by coincidence have the same OID, since they live in
> different system catalogs.
>
> regards, tom lane
>