STI questions...

rubyonrails-talk
1

i have an Order model and a table for addresses. i was trying to use single table inheritance so that i can store the addresses in the same table.

here is my order model:

class Order < ActiveRecord::Base

  has_one :billing_address, :class_name => 'BillingAddress', :foreign_key => 'order_id'   has_one :shipping_address, :class_name => 'ShippingAddress', :foreign_key => 'order_id' end

and the address model:

class Address < ActiveRecord::Base end

class BillingAddress < Address   belongs_to :order, :class_name => 'Order' end

class ShippingAddress < Address   belongs_to :order, :class_name => 'Order' end

everything appears to be working fine, unless i try and do something like this:

my_order.billing_address.create(...)

i get this in the console:

NoMethodError: You have a nil object when you didn't expect it! You might have expected an instance of ActiveRecord::Base. The error occurred while evaluating nil.create

however, if i create an address this way:

BillingAddress.create(....... :order => my_order) it works fine. i can even use order.billing_address and it will pull up the right record.

is this right, or did i set up the relationships wrong?

2

Josh wrote:

class Order < ActiveRecord::Base has_one :billing_address, :class_name => 'BillingAddress', :foreign_key => 'order_id'

everything appears to be working fine, unless i try and do something like this:

my_order.billing_address.create(...)

i get this in the console:

NoMethodError: You have a nil object when you didn't expect it! You might have expected an instance of ActiveRecord::Base. The error occurred while evaluating nil.create

The correct syntax is my_order.create_billing_address(...)