Processing Tables containing tree-like data

Hi,

I have a table which looks like this:

id info parentid
0 <God> 0
1 Adam 0
2 Cain 1
3 Abel 1
4 Seth 1
5 Enosh 4
....

I am looking for a fast and efficient way of finding ALL the descendents
of any particular node, to unlimited depth.

Is there a standard database trick for doing this efficiently ? Writing
a recursive function would be extremely inefficient for repeated
queries.

Thanks,

Netzach