Re: query to select a linked list

On Wed, May 09, 2007 at 02:24:22PM +0100, Gregory Stark wrote:
> "Louis-David Mitterrand" <vindex+lists-pgsql-sql@apartia.org> writes:
> 
> > Each message a unique id_forum and an id_parent pointing to the replied 
> > post (empty if first post).
> >
> > How can I build an elegant query to select all messages in a thread?
> 
> You would need recursive queries which Postgres doesn't support. There is a
> patch out there to add support but I don't think it's up-to-date with 8.2 and
> in any case the resulting queries can be quite intense.
> 
> I would recommend you look into the contrib module named "ltree". It's easy to
> use and works well with the gist indexes. It does require changing your data
> model denormalizing it slightly which makes it hard to "reparent" children,
> but if that isn't an operation you have to support I think it makes most other
> operations you might want to do much easier to support.

After looking around a little I came to the same conclusions.

Thanks for you help,

Cheers,