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Diffstat (limited to 'activerecord/lib/active_record/acts/tree.rb')
| -rw-r--r-- | activerecord/lib/active_record/acts/tree.rb | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/acts/tree.rb b/activerecord/lib/active_record/acts/tree.rb new file mode 100644 index 0000000000..f05bbe9a78 --- /dev/null +++ b/activerecord/lib/active_record/acts/tree.rb @@ -0,0 +1,40 @@ +module ActiveRecord + module Acts + # 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.extend(ClassMethods) + end + end + + module ClassMethods + def acts_as_tree(options = {}) + configuration = { :foreign_key => "parent_id", :order => nil } + configuration.update(options) if options.is_a?(Hash) + + belongs_to :parent, :class_name => name, :foreign_key => configuration[:foreign_key] + has_many :children, :class_name => name, :foreign_key => configuration[:foreign_key], :order => configuration[:order], :dependent => true + end + end + end +end
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