= AwesomeNestedSet
Awesome 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.
== Installation
If you are on Rails 2.1 or later:
script/plugin install git://github.com/collectiveidea/awesome_nested_set.git
== Usage
To 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 Helper
The 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.
== References
You 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 (c) 2008 Collective Idea, released under the MIT license
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