Rails - Aug 2007 - write_attribute functionality for related objects?

Hi. Given:

class Group < AR
  has_many :users
end

Is it in any way possible to retain reference to the old users when
they get replaced using group.users=(new_users) ?

The below doesn''t work but illustrates what I''m looking for:

class Group < AR
  has_many :users
  def users=(new_users)
    @old_users = users
    write_attribute(''users'', new_users)
  end
end

I need to examine the differences when related objects (in this case
users) change.

Morten


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> The below doesn''t work but illustrates what I''m looking
for:
>
> class Group < AR
>   has_many :users
>   def users=(new_users)
>     @old_users = users
>     write_attribute(''users'', new_users)
>   end
> end
I''m currently doing something like this:

class Group < AR
  has_many :users
  def validate_on_update
    old_users = Group.find(id).users
    #Do the checks here..
  end
end

But that''s nasty. Anyone know if there''s a plugin that allows
AR to
contain a version of the object in the state it had as it got read
from the DB for later comparison?



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