I was have made a module like ltree, i don't know how you implement it, but mine doesn't fit.
The problem : for ex. you need to select a tree, but with childs of each parent is sorted. in my module i've defined a tree path as set of numbers separated by dot ('1.234.456.789'::hier for ex.), a comparision operators <,>,<=,<=,= , operators for checking for ancestors/descedants <<,>>,<<=,>>=. create table t (field text, node::hier); then i do "select field from t where where node <<'1' order by node"; 'order by' - for tuples being in order of tree (first is root,then first child, then first child of first child, .. so on). works perfectly well. THE MATTER OF PROBLEM: tuples can't be sorted alphabetically by 'field', because of 'order by node' clause. 'order by node,field' doesn't really work because 'node' is first key, if 'order by field,node' - then we don't get a tree. if i do nodes on one level is equal, then childs of one node in some cases are migrate to another node of same level :) as far as i understand problem is in pg's sort. it's not a bug but feature of sort alghorithm. The minor problem is that such tree a bit difficult to maintain. for ex. if i need to move some node to elsewhere in tree, i need to update all childs, sub childs, ... of this node. regards --- .evgen On Fri, 15 Nov 2002, Oleg Bartunov wrote: > Evgen, > > you'd need to post your message and patch to hackers mailing list. > btw, did you try contrib/ltree module ? > > Regards, > Oleg > _____________________________________________________________ > Oleg Bartunov, sci.researcher, hostmaster of AstroNet, > Sternberg Astronomical Institute, Moscow University (Russia) > Internet: [EMAIL PROTECTED], http://www.sai.msu.su/~megera/ > phone: +007(095)939-16-83, +007(095)939-23-83 > > ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html