Return-Path: pg_adm@postgres.berkeley.edu Received: by postgres.Berkeley.EDU (5.61/1.29) id AA00861; Fri, 1 Nov 91 09:11:03 -0800 Message-Id: <9111011711.AA00861@postgres.Berkeley.EDU> From: Peter van Oosterom Subject: oid mapping To: postgres@postgres.berkeley.edu Sender: pg_adm@postgres.berkeley.edu To: postgres@postgres.berkeley.edu Date: Fri, 1 Nov 91 18:14:21 MET Cc: tom@izf.tno.nl X-Mailer: ELM [version 2.3 PL11] Dear Postgres group, The reference manual distributed with version 2.0.3 contained a section on oid mapping in the postquel copy command. This section has disappeared in the latest reference manual. However, oid mapping is important in case you want to copy a database from one postgres installation to another. The oid mapping described in reference manual version 2.0.3 is not sufficient for this purpose. The auxiliary relation which contains the mapping of old oid's to new oid's can not be filled because the copy to and from are performed on two different installations. A reasonable solution for the oid mapping is illustrated with an example: ON SYSTEM A: create people(name=char16,parent=oid) append's..... retrieve into cppeople (oldoid=people.oid, people.all) copy cppeople to "/tmp/people.data" (transport file /tmp/people.data from A to B) ON SYSTEM B: create people(oldoid=oid,name=char16,parent=oid) copy people from "/tmp/people.data" replace people(parent=p.oid) from p in people where p.oldoid=people.parent dropattr (oldoid) from people Everything works, except the last two lines. The replace command causes an infinite loop. Of course the command dropattr is not present, but it should be able to implement this similar to addattr. Another disadvantage is that this method is clumsy. For example the cppeople-relation would not be needed if something like copy people(oldoid=oid,all) to "/tmp/people.data" was possible. Is there a (better) method to solve this problem? Regards, Peter van Oosterom.