Alvaro Herrera <alvherre@commandprompt.com> writes:
> Felix Kater wrote:
>> 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?
> Yes, the table OID is unique, and pg_attribute.attnum is unique as well.
> They are not reused, not even when columns are dropped.
The OID could be re-used after the table is dropped, though. It's not
clear whether Felix needs uniqueness across time or just at any one
instant.
regards, tom lane