¶ ↑
AwesomeNestedSetAwesome Nested Set is an implementation of the nested set pattern for ActiveRecord models. It is replacement for acts_as_nested_set and BetterNestedSet, but awesomer.
¶ ↑
What makes this so awesome?This is a new implementation of nested set based off of BetterNestedSet that fixes some bugs, removes tons of duplication, adds a few useful methods, and adds STI support.
¶ ↑
InstallationIf you are on Rails 2.1 or later:
script/plugin install git://github.com/collectiveidea/awesome_nested_set.git
¶ ↑
UsageTo make use of awesome_nested_set, your model needs to have 3 fields: lft, rgt, and parent_id:
class CreateCategories < ActiveRecord::Migration def self.up create_table :categories do |t| t.string :name t.integer :parent_id t.integer :lft t.integer :rgt end end def self.down drop_table :categories end end
Enable the nested set functionality by declaring acts_as_nested_set on your model
class Category < ActiveRecord::Base acts_as_nested_set end
Run ‘rake rdoc` to generate the API docs and see CollectiveIdea::Acts::NestedSet::SingletonMethods for more info.
¶ ↑
View HelperThe view helper is called #nested_set_options.
Example usage:
<%= f.select :parent_id, nested_set_options(Category, @category) {|i| "#{'-' * i.level} #{i.name}" } %> <%= select_tag 'parent_id', options_for_select(nested_set_options(Category) {|i| "#{'-' * i.level} #{i.name}" } ) %>
See CollectiveIdea::Acts::NestedSet::Helper for more information about the helpers.
¶ ↑
ReferencesYou can learn more about nested sets at:
http://www.dbmsmag.com/9603d06.html http://threebit.net/tutorials/nestedset/tutorial1.html http://api.rubyonrails.com/classes/ActiveRecord/Acts/NestedSet/ClassMethods.html http://opensource.symetrie.com/trac/better_nested_set/
Copyright © 2008 Collective Idea, released under the MIT license