saving associated models...is there any order to it?

Hi,

If I have 2 models defined as such:

class ClassA < ActiveRecord::Base
  before_create "class_b.foo"
  has_one :class_b
  def foobar
    puts "foobar"
  end
end

ClassB < ActiveRecord::Base
  after_create :bar
  belongs_to :class_a
  def foo
    puts "foo"
  end
  def bar
    class_a.foobar
  end
end

And somewhere I do this:

a = ClassA.new
b = ClassB.new
a.class_b = b
a.save

Which object will get created first, and in turn, have it's lifecycle
method called first? In other words, will ClassA definitely get
created before ClassB, or vise versa? Is there any guarantee to the
order of saving objects in the graph?

Thanks in advance,

Ryan

Anybody?