All all! I'm a newbie here, please look my example code:

  r = Page.find :all, :conditions => "is_default = 'true'"
  assert_equal 1, r.length
  r = Page.create NEW_INSTANCE_DATA
  assert !r.new_record?
  r = Page.find :first, :conditions => "name = 'privacy_policy'"
  assert_not_nil r
  assert r.is_default

if I writing this way~ it there any effect to saving memory?
(because I think the old instance are always released in time.)