ok, got it. thanks for the clarification and the hand holding. -Whit On Mon, Apr 27, 2009 at 1:09 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Whit Armstrong <armstrong.whit@xxxxxxxxx> 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 > -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
