64 lines
1.9 KiB
Plaintext
64 lines
1.9 KiB
Plaintext
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= AwesomeNestedSet
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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.
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== What makes this so awesome?
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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.
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== Installation
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If you are on Rails 2.1 or later:
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script/plugin install git://github.com/collectiveidea/awesome_nested_set.git
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== Usage
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To make use of awesome_nested_set, your model needs to have 3 fields: lft, rgt, and parent_id:
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class CreateCategories < ActiveRecord::Migration
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def self.up
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create_table :categories do |t|
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t.string :name
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t.integer :parent_id
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t.integer :lft
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t.integer :rgt
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end
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end
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def self.down
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drop_table :categories
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end
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end
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Enable the nested set functionality by declaring acts_as_nested_set on your model
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class Category < ActiveRecord::Base
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acts_as_nested_set
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end
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Run `rake rdoc` to generate the API docs and see CollectiveIdea::Acts::NestedSet::SingletonMethods for more info.
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== View Helper
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The view helper is called #nested_set_options.
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Example usage:
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<%= f.select :parent_id, nested_set_options(Category, @category) {|i| "#{'-' * i.level} #{i.name}" } %>
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<%= select_tag 'parent_id', options_for_select(nested_set_options(Category) {|i| "#{'-' * i.level} #{i.name}" } ) %>
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See CollectiveIdea::Acts::NestedSet::Helper for more information about the helpers.
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== References
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You can learn more about nested sets at:
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http://www.dbmsmag.com/9603d06.html
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http://threebit.net/tutorials/nestedset/tutorial1.html
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http://api.rubyonrails.com/classes/ActiveRecord/Acts/NestedSet/ClassMethods.html
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http://opensource.symetrie.com/trac/better_nested_set/
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Copyright (c) 2008 Collective Idea, released under the MIT license
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