class Owner < ActiveRecord::Base self.primary_key = :owner_id has_many :pets, -> { order "pets.name desc" } has_many :toys, through: :pets has_many :persons, through: :pets belongs_to :last_pet, class_name: "Pet" scope :including_last_pet, -> { select(' owners.*, ( select p.pet_id from pets p where p.owner_id = owners.owner_id order by p.name desc limit 1 ) as last_pet_id ').includes(:last_pet) } after_commit :execute_blocks accepts_nested_attributes_for :pets, allow_destroy: true def blocks @blocks ||= [] end def on_after_commit(&block) blocks << block end def execute_blocks blocks.each do |block| block.call(self) end @blocks = [] end end