Question

I want to do some seemingly simple associations:

class OrderWizard < ActiveRecord::Base
  belongs_to :buyer_wizard,     :class_name => MiniWizard.name
  belongs_to :seller_wizard,    :class_name => MiniWizard.name
end

class MiniWizard < ActiveRecord::Base
   has_one :order_wizard, :foreign_key = '????' # Could be buyer_wizard_id or seller_wizard_id

   def is_buyer_wizard?
     ??
   end

   def is_seller_wizard?
     ??
   end
end

1. An associated MiniWizard needs to know who is connecting to it. Assuming has_many :through best way to go? If so, how would the models look?

2. A MiniWizard instance needs to know if it’s a buyer or seller. Stuck on how to do this.

Answer 1

You actually probably want two associations, for example, something like this might represent the relationships more accurately:

class MiniWizard < ActiveRecord::Base
   has_one :bought_order_wizard, :foreign_key => 'buyer_wizard_id', :class_name => 'MiniWizard'
   has_one :sold_order_wizard, :foreign_key => 'seller_wizard_id', :class_name => 'MiniWizard'

  def order_wizard
    bought_order_wizard || sold_order_wizard
  end

  def is_buyer_wizard?
    !bought_order_wizard.nil?
  end

  def is_seller_wizard?
    !sold_order_wizard.nil?
  end
end