On 17/05/2011 19:07, Carlos Mennens wrote:
On Tue, May 17, 2011 at 12:57 PM, Carlos Mennens
<carlos.menn...@gmail.com>  wrote:
On Tue, May 17, 2011 at 12:38 PM, Raymond O'Donnell<r...@iol.ie>  wrote:
Yes, that's exactly right - SERIAL does it all for you. The mistake some
people make, on the other hand, is thinking that SERIAL is a type in its own
right - it's not, it just does all those steps automatically.

So if I have an existing column in my table with a INT data type, I
can't seem to understand how to convert this on my 8.4 production
server:

ALTER TABLE users ALTER COLUMN id TYPE SERIAL;
ERROR:  type "serial" does not exist

That's because of what I just mentioned above. :-) It's not a type: it's just a shortcut. What you need to do instead is something like this:

  -- Create the sequence.
  create sequence users_id_seq;

  -- Tell the column to pull default values from the sequence.
  alter table users alter column id set default nextval('users_id_seq');

  -- Establish a dependency between the column and the sequence.
  alter sequence users_id_seq owned by users.id;

HTH

Ray.


--
Raymond O'Donnell :: Galway :: Ireland
r...@iol.ie

--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general

Reply via email to