可以逆多态关联吗？

Question

I have four models : User, Product, Ownership, and Location. Product belongs to User through Ownership and User has many Products through Ownership. When a User create a Product, I want that if the User has a Location, the Product is linked to the same Location. So here is my question :

Can we transform this :

class Location < ActiveRecord::Base
  belongs_to :localizable, polymorphic: true
end

class User < ActiveRecord::Base
  has_one :location, as: :localizable
end

class Product < ActiveRecord::Base
  has_one :location, as: :localizable
end

into this :

class Location < ActiveRecord::Base
  has_many :localizables, polymorphic: true
end

class User < ActiveRecord::Base
  belongs_to :location, as: :localizable
end

class Product < ActiveRecord::Base
  belongs_to :location, as: :localizable
end

Answer 1

How about delegating product.location to product.owner.location .

This can be done in the Product class as follows (change identifier for the owner/user relation as needed):

class Product < ActiveRecord::Base
  delegate :location, to: :owner
end

If you call product.location , the location of the owner will be returned.