From 95314be65be197b6c38c8c93e3f8d1e8b5b0b674 Mon Sep 17 00:00:00 2001 From: David Heinemeier Hansson Date: Wed, 15 Dec 2004 00:46:26 +0000 Subject: Added tree mixin and unit tests for all the mixins git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@156 5ecf4fe2-1ee6-0310-87b1-e25e094e27de --- activerecord/lib/active_record/mixins/tree.rb | 36 +++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 activerecord/lib/active_record/mixins/tree.rb (limited to 'activerecord/lib/active_record/mixins/tree.rb') diff --git a/activerecord/lib/active_record/mixins/tree.rb b/activerecord/lib/active_record/mixins/tree.rb new file mode 100644 index 0000000000..582aa09b4b --- /dev/null +++ b/activerecord/lib/active_record/mixins/tree.rb @@ -0,0 +1,36 @@ +module ActiveRecord + module Mixins + # Including this mixin if you want to model a tree structure by providing a parent association and an children + # association. This mixin assumes that you have a column called parent_id + # + # class Category < ActiveRecord::Base + # include ActiveRecord::Mixins::Tree + # end + # + # Example : + # root + # \_ child1 + # \_ sub-child1 + # + # 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 + module Tree + + def self.append_features(base) + super + + base.module_eval <<-associations + belongs_to :parent, :class_name => name, :foreign_key => "parent_id" + has_many :children, :class_name => name, :foreign_key => "parent_id", :order => "id", :dependent => true + associations + + end + end + end +end \ No newline at end of file -- cgit v1.2.3