Question

I don’t get it I have the following models:

class Seller < ActiveRecord::Base
  has_many :cars, :dependent => :destroy
end

class Car < ActiveRecord::Base
  belongs_to :seller
  # I have tried both with the validates existence gem:
  validates :existence => {:allow_nil => false}
  # And normally...
  validates_presence_of :seller
end

But nothing works if I do the following:

seller = Seller.new()
seller.cars.build()
seller.save # I get => false @messages={:seller=>["does not exist"], :seller_id=>["does not exist"]}  

I should be able to do this right?

It’s like – it’s validating the associated model before the mother-object has been saved – and i have NOT defined a validates_associated or something like that.

Any clue? Or am I getting the order of saving and validating all wrong?

Answer 1

I have run into this in the past, and have used “inverse_of” to solve it. You also need “accepts_nested_attributes_for”. So in the seller, you would want to change your code to the following:

class Seller < ActiveRecord::Base
  has_many :cars, :dependent => :destroy, :inverse_of => :seller
  accepts_nested_attributes_for :cars
end