Felix Kater wrote: > Hi, > > I need a unique ID across all columns I create. Is it o.k. to > achive this by combining pg_attribute.attnum of a column together with > the OID of the table the column is in? > > While the table's OID should be unique according to the manual, I have > found no hints about the uniqueness of attnum -- I removed and added > some columns and it seems that already used values are not used again. Yes, the table OID is unique, and pg_attribute.attnum is unique as well. They are not reused, not even when columns are dropped. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.
