gistfile1.txt

#Modeling Parent Child Relationships

rails new confusingTitleProject
cd confusingTitleProject
rails g model Person name:string
rails g model PersonRelationship parent_id:integer child_id:integer



#App/Models/PersonRelationship.rb
class PersonRelationship < ActiveRecord::Base
  belongs_to :parent, :class_name => "Person"
  belongs_to :child, :class_name => "Person"
end



#App/Models/Person.rb
class Person < ActiveRecord::Base
  
  validates_presence_of :first_name, :last_name

  has_many     :parent_child_relationships,
               :class_name            => "PersonRelationship",
               :foreign_key           => :child_id,
               :dependent             => :destroy
  has_many     :parents,
               :through               => :parent_child_relationships,
               :source                => :parent

  has_many     :child_parent_relationships,
               :class_name            => "PersonRelationship",
               :foreign_key           => :parent_id,
               :dependent             => :destroy
  has_many     :children,
               :through               => :child_parent_relationships,
               :source                => :child
end


#As an example
a = Person.new; b = Person.new
b.parents = [a]