An alternative to nested_sets and acts_as_tree. Designed to be a drop in replacement for acts_as_tree. Replaces betternestedset without the slow inserts when dealing with a large dataset. Used by upillar.com on a dataset of over 900,000 categories with no slow downs. In tests it shows a 285% speed increase on inserts with a dataset of 100k categories. As datasets become larger its insert speed stays about the same when nested_sets become slower. In all of my tests read speeds have been comparable with nested sets on everything but all_children which is inperceptibly slower on a dataset of 100k than betternestedset.

Add this line to your application's Gemfile:

gem 'acts_as_better_tree'

And then execute:

$ bundle

Or install it yourself as:

$ gem install acts_as_better_tree

Required fields are parent_id, root_id, csv_ids.

create_table :categories do |t|
 t.column :root_id, :integer
 t.column :parent_id, :integer
 t.column :csv_ids, :string
 t.column :name, :string
end

If upgrading from acts_as_tree just add root_id and csv_ids and run Category.tree_to_better_tree!

class Category < ActiveRecord::Base
    acts_as_better_tree :order => "name"
end

Example:
root
\_ child1
    \_ subchild1
    \_ subchild2

root      = Category.create("name" => "root")
child1    = root.children.create("name" => "child1")
subchild1 = child1.children.create("name" => "subchild1")

root.parent   # => nil
child1.parent # => root
root.children # => [child1]
root.children.first.children.first # => subchild1
child1.self_and_ancestors # => [root, child1]
child1.ancestors
child1.siblings
child1.self_and_siblings
child1.move_to_child_of(parent)
child1.childless?
child1.ancestor_of?(subchild1)
child1.descendant_of?(root)
root.to_csv # => "root,child1,subchild1\n" returns and array of all children
Category.to_csv # => "root,child1,subchild1\nroot,child1,subchild2\n" returns entire tree in a csv string

Copyright (c) 2008 Isaac Sloan, released under the MIT license. Inspired by David Heinemeier Hansson's acts_as_tree

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request