Model without database table?

Is it possible to make a model that does not map to a database table?
If so how?

A "model" is a class that represents something in the problem domain, Rails does not assume it is persistent. Just define a class Foo in app/models/foo.rb without inheriting from AR::Base.

-- fxn

I'm studying rails
I am coding depot application in Agile web development with rails book
I have Cart model code like that :

class Cart

   attr_reader :items

   def initialize
     @items = []
   end

   def add_product(product)
     current_item = @items.find {|item| item.product == product}
     if current_item
       current_item.increment_quantity
     else
       @items << CartItem.new(product)
     end
   end

   def total_price
     @items.sum { |item| item.price }
   end
end
above code is same with that of the book
but depot app have a error
Cart class doesn't inherit from ActiveRecode::Base
But, Error message is like that
>> c = Cart.new
ActiveRecord::StatementInvalid: Mysql::Error: #42S02Table
'depots_development.carts' doesn't exist: SHOW FIELDS FROM `carts`

plz, help me~

2008. 02. 25, 오후 6:28, Xavier Noria 작성:

Sorry for the late answer, maybe it will be usefull for someone else.

You can use the following plugin:
http://agilewebdevelopment.com/plugins/activerecord_base_without_table