[ANN] better nested set 0.1

We are pleased to announce the 0.1 release of the plugin
betternestedset. It greatly enhances ActiveRecord’s internal

Install it with:
script/plugin install

Join the mailing list:

Report bugs:

A nested set is a smart way to implement an ordered tree that allows
for fast, non-recursive queries. For example, you can fetch all
descendants of a node in a single query, no matter how deep the tree.
The drawback is that insertions/moves/deletes require complex SQL, but
that is handled behind the curtains by this plugin!

Nested sets are appropriate for ordered trees (e.g. menus, commercial
categories) and large trees that must be queried efficiently (e.g.
threaded posts). Nested sets provide greatly improved read performance
at the cost of reduced write performance, which is a worthwhile trade
for most web applications.

Migrating from an ordinary adjacency list tree (such as acts_as_tree)
is not complex, particularly if your table contains only a single

NOTE: This 0.1 release will be the only one fully backwards-compatible
with the original acts_as_nested_set. The add_child method will be
dropped in the future, and the possibility of having a root defined by
parent_id == 0 will be removed.

0.2 will add …
A promising branch is being built by Krishna D. to provide an even
simpler API, closer to that of acts_as_tree. Grab it from
svn://rubyforge.org/var/svn/betternestedset/branches/ez-set and test
it out.

betternestedset is brought up to you by Jean-Christophe M.,
greatly helped by Krishna D. and other contributors.

Jean-Christophe M.