Frustrating Problem - Acts As Tree

I am a ruby on Rails Novice and I am having an extremely frustrating problem - not sure whether acts_as_tree plug in is causing this or not (or me lacking a fundamental misunderstanding of rails)

I have the following table schema:

create_table "destinations", :force => true do |t|
   t.string "name"
   t.string "description"
   t.integer "commissions_rate", :default => 0
   t.integer "destinations_count", :default => 0
   t.integer "position"
   t.datetime "created_at"
   t.datetime "updated_at"
end

and model def:

class Destination < ActiveRecord::Base
attr_accessible :id, :name, :parent_id, :centre_longitude, :centre_latitude, :commissions_rate, :position, :startzoom, :description, :destinations_count

acts_as_tree :counter_cache => true

end

I am trying to adjust the update method in my controller so that if the parent commissions_rate is modified the "children" records of the parent are automatically updated with this value, code as follows:

def update
   @destination = Destination.find(params[:id])
   @rate = @destination.commissions_rate || 0
   @children = @destination.children
   if (@destination.destinations_count > 0)
     for child in @children do
       child.commissions_rate = @rate
     end
   end
   respond_to do |format|
     if @destination.update_attributes(params[:destination])
       flash[:notice] = 'Destination was successfully updated.'
      .........
end

The form only send data for the parent model (not using nested model)

Everything works when I test the above code in the Rails console however when running the server the children are failing to have the commission_rate variable updated.
Would appreciate any help anyone can provide me.

Thanks

David

You're not saving the child after you update it's value

    for child in @children do
      child.commissions_rate = @rate
      child.save
    end

or

    for child in @children do
      child.update_attribute(:commissions_rate, @rate)
    end

.update_attribute automatically saves, check the Rails API docs for
more info on using this method.

PS You're using a lot of instance variables there, which seem like
there would be better scoped as local variables (ie drop the @ from
the variables unless you need them to be accessible on an instance of
the object - @destination is probably the only legitimate instance
variable)

Many thanks Michael, it solved the problem, and thanks for the extra
advice I need it! as where I am based (Indonesia) no one teaches
rails.