Rails - Jun 2006 - Active Record question, orphaned children

I have a Deck object and a Card object with their corresponding tables. (You
know a deck of cards.)  When I destory a Deck it leaves orphaned cards in
the database. Is there a way to set up the objects with ActiveRecord so that
when a parent object is destoryed the child objects are destroyed as well?
My code below.

class Deck < ActiveRecord::Base
  has_many :cards
end

class Card < ActiveRecord::Base
  belongs_to :deck
end

  def destroy
    Deck.find(params[:id]).destroy
    redirect_to :action => ''list''
  end
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Michael Whitman wrote:
> I have a Deck object and a Card object with their corresponding tables. 
> (You know a deck of cards.)  When I destory a Deck it leaves orphaned 
> cards in the database. Is there a way to set up the objects with 
> ActiveRecord so that when a parent object is destoryed the child objects 
> are destroyed as well? My code below.
> 
Take a look at the :dependent option for has_many associations:

http://api.rubyonrails.com/classes/ActiveRecord/Associations/ClassMethods.html#M000530

:dependent - if set to :destroy all the associated objects are destroyed 
alongside this object by calling their destroy method. If set to 
:delete_all all associated objects are deleted without calling their 
destroy method. If set to :nullify all associated objects? foreign keys 
are set to NULL without calling their save callbacks. NOTE: :dependent 
=> true is deprecated and has been replaced with :dependent => :destroy. 
May not be set if :exclusively_dependent is also set.

So you want something like:

class Deck < ActiveRecord::Base
   has_many :cards, :dependent => :destroy
end

class Card < ActiveRecord::Base
   belongs_to :deck
end

hth

-- 
R.Livsey
http://livsey.org