class CreateNsSeconds < ActiveRecord::Migration

  def change

    create_table :ns_seconds do |t|

      t.references :first, :null => false

 

      t.timestamps

    end

    add_index :ns_seconds, :ns_first_id, :unique => true

  end

end

class CreateNsFirsts < ActiveRecord::Migration

  def change

    create_table :ns_firsts do |t|

 

      t.timestamps

    end

  end

end

 

class CreateNsSeconds < ActiveRecord::Migration

  def change

    create_table :ns_seconds do |t|

      t.references :ns_first, :null => false

 

      t.timestamps

    end

    add_index :ns_seconds, :ns_first_id, :unique => true

  end

end

class Ns::First < ActiveRecord::Base

  has_one :second_model, :class_name => "Ns::Second"

end

 

class Ns::Second < ActiveRecord::Base

  belongs_to :ns_first

end

xandox@stitche /tmp/test_app$ rails console

Loading development environment (Rails 3.1.0.rc1)

irb(main):001:0> f = Ns::First.new

=> #<Ns::First id: nil, created_at: nil, updated_at: nil>

irb(main):002:0> f.second_model

=> nil

irb(main):003:0> f.build_second_model

ActiveRecord::UnknownAttributeError: unknown attribute: first_id

    from /var/lib/gems/1.8/gems/activerecord-3.1.0.rc1/lib/active_record/base.rb:1728:in `assign_attributes'

    from /var/lib/gems/1.8/gems/activerecord-3.1.0.rc1/lib/active_record/base.rb:1722:in `each'

    from /var/lib/gems/1.8/gems/activerecord-3.1.0.rc1/lib/active_record/base.rb:1722:in `assign_attributes'

    from /var/lib/gems/1.8/gems/activerecord-3.1.0.rc1/lib/active_record/associations/singular_association.rb:30:in `build'

    from /var/lib/gems/1.8/gems/activerecord-3.1.0.rc1/lib/active_record/associations/builder/singular_association.rb:33:in `build_second_model'

    from (irb):3

irb(main):004:0>