Specify this acts_as extension if you want to model a tree structure by providing a parent association and a children association. This requires that you have a foreign key column, which by default is called parent_id.
In terminal:
rails g model Category name:string parent_id:integer
Should generate a migration
class CreateCategories < ActiveRecord::Migration def self.up create_table :categories do |t| t.string :name t.integer :parent_id t.timestamps end end def self.down drop_table :categories end end
In terminal:
rake db:migrate
Should create the database table called 'categories'.
# app/models/category.rb class Category < ActiveRecord::Base acts_as_tree :order => "name" end
# db/seed.rb root = Category.create("name" => "root") child1 = root.children.create("name" => "child1") subchild1 = child1.children.create("name" => "subchild1")
In terminal:
rake db:seed
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
Copyright (c) 2007 David Heinemeier Hansson, released under the MIT license
Includes patch from http://dev.rubyonrails.org/ticket/1924