"Reggie Burnett" <[EMAIL PROTECTED]> writes: > I have started experimenting with an access layer for pgsql and have a > question. I had someone on this list tell me that the oid values that > come back from the server are tag identifiers for that row/column > combination and are not type indicators.
I think your someone is confused. There are no identifiers associated with row/column combinations. > Yet, when I create multiple > tables/columns each having the same type (int32), the same oid keeps > being returned. The OIDs returned in RowDescription messages uniquely identify datatypes (more specifically, pg_type rows). They will be stable short of DROP TYPE/CREATE TYPE shenanigans. (However, user-defined types might not get the same OIDs assigned after a dump/reload cycle. It's probably reasonable to treat type OIDs as stable for the life of a connection, but not as constants of nature.) OIDs are also used for other purposes, so your confusion may stem from confusing pg_type OIDs with other OIDs. In the current system implementation, OIDs are unique row identifiers only within individual tables --- perhaps not even then, if the table doesn't have a unique index on its OID field. Thus, a pg_type OID uniquely identifies a datatype, but that doesn't mean that the same OID number could not appear in pg_class, pg_rewrite, or other system or user tables. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly