(Building trees with a dash of sanity)

This is a drop in replacement for acts_as_tree on systems with Postgresql >= 8.4

What this provides

A fast way to build trees.

What version of Rails

  • Rails ~> 4.1.0

  • Rails ~> 4.0.0

  • Rails ~> 3.2.0

  • Rails ~> 3.1.0

  • Rails ~> 3.0.0

  • Rails ~> 2.3.0


  • PostgreSQL version >= 8.4

  • ActiveRecord


Same as acts_as_tree. Basically: Specify a parent_id or the column that holds the parent ID information.

class MyFancyTree < ActiveRecord::Base


A few extras are provided. Of note are:

  • #depth -> depth from root of the current node

  • #descendents -> all descendents of the current node (provided in either scope or nested hash)

  • nodes_within?(src, chk) - Returns true if chk contains any nodes found within src and all ancestors of nodes within src

  • nodes_within(src, chk) - Returns any matching nodes from chk found within src and all ancestors within src

  • nodes_and_descendents(*args) - Returns all nodes and descendents for given IDs or records. Provided in either scope or nested hash.

  • Works properly with STI

  • Adds 'depth' attribute to returned model instances


Yes, there is documentation. Please read it and find all the fun tools at your fingertips:


  • Thanks to David Hansson for the original

  • Thanks to PostgreSQL for providing tools for sanity


A (now not so large) majority of this was copied directly from the original acts as tree, with the original license:

  • Copyright © 2007 David Heinemeier Hansson, released under the MIT license

The new additions continue:

  • Copyright © 2011 Chris Roberts, released under the MIT license