recursive seek...?

Kello!

I have a recusive relation, like this:
=> create table re( name text, oid parent);
and needed the name from a tuple, and the name of all parents...
i tryd some, like:
=> create function fullname(oid) returns text
-> as 'select fullname(re.parent) || re.name from re where re.oid=$1;'
-> language 'sql';
that isn't work. of course ;(

 i can get a name, and the parents oid, and the oid of parents parent etc...
 with _MORE_ queries.

for example:
=> select oid,* from re;
oid | name | parent
----+------+--------
5000|one   | (NULL or 0)
5001|two   | 5000
5002|3d    | 5000
5003|4d    | 5002
i now the oid:5003. i need the name: "one/two/4d"
must i send thees queries to the backend? (in pseudo code):
$curr=5003
$fulln=''
while $curr do
  => SELECT name, parent FROM re WHERE oid=$curr;
  $fulln='$fulln/$name'; $curr=$parent;
enddo
so i liked send _ONLY_ 5003, and reveive in a trice the full name.
this time i can't this ;(

sprintf         ("`-''-/").___..--''"`-._            Error In
("%|s",          `6_ 6  )   `-.  (     ).`-.__.`)    Loading Object
"Petike"         (_Y_.)'  ._   )  `._ `. ``-..-'     line:3
/* Neko */     _..`--'_..-_/  /--'_.' ,'             Before /*Neko*/
 );           (il),-''  (li),'  ((!.-'     see: http://lsc.kva.hu