gistfile1.txt

#!/usr/bin/env ruby

require 'dm-core'

class Foo
  include DataMapper::Resource
  property :id, Serial

  has n, :bars
end

class Bar
  include DataMapper::Resource
  property :id, Serial

  # Does not belong to foo.
  #belongs_to :foo, :nullable => true

  def foo
    puts 'I never get called.'
  end

  def foo=(other)
    puts 'neither do i'
  end
end

DataMapper.setup(:default, 'sqlite3::memory:')
DataMapper.auto_migrate!

foo = Foo.create
foo.bars.create
bar = foo.bars.first

bar.foo = 'boom'

bar.foo # also boom