"paul.dorman" <paul.dorman@gmail.com> writes:
> Hi everyone,
>
> I would like to know the best way to implement a DAG in PostgreSQL. I
> understand there has been some talk of recursive queries, and I'm
> wondering if there has been much progress on this.
The ANSI recursive queries didn't make it into 8.3. I still hope it makes 8.4.
You could check out the tablefunc contrib which includes a function called
connectby() which implements a kind of recursive query.
Alternatively you might look at the ltree contrib module but that doesn't work
the way you describe. It denormalizes the data for very fast but less flexible
operations.
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com