gistfile1.txt

#!/usr/bin/ruby

require 'rubygems'
require 'data_objects'  # current master @ ed1ceefc
require 'dm-core'       # current master @ 73860575
require 'dm-migrations' # current master @ ab608e81

class Order
    include ::DataMapper::Resource

    property :id, Serial

    has 0..n, :order_items
end

class OrderItem
    include ::DataMapper::Resource

    property :id,     Serial
    belongs_to :order
end

::DataMapper.setup(:default, 'mysql://127.0.0.1/test')
::DataMapper.auto_migrate!

o1 = Order.create
o2 = Order.create

i1 = OrderItem.create :order_id => o1.id
i1 = o1.order_items.first

puts "assigning i1's order_id to 2..."
i1.order_id = 2
i1.save
puts "we just saved i1 and i1.clean? is #{i1.clean?}"

puts "lets reload i1..."
i1.reload # reload attributes from DB but ALSO divorces/unbinds from the association/parent?
puts "i1.order_id should be 2 but it is #{i1.order_id}"

puts "lets assign i1's order_id to 2 again..."
i1.order_id = 2
i1.save
puts "we just saved i1 and i1.clean? is #{i1.clean?}"

puts "lets reload i1"
i1.reload
puts "i1.order_id should be 2 and now it is #{i1.order_id}"