Question

I have a simple cart system that I have been working on for a little while for an application and am needing a little help in trying to figure out how to update a particular attribute in a join table (Between Order and Products).

Here is the code:

def add_product_to_cart
        @product = Product.by_client(current_client).first 
        @order = current_order
        unless @order.products.exists? :id => @product.id
            @order.products << @product
        end
    end

I am trying to update a particular attribute when I update the @order.products…

This is what I am trying to do:
@order.products << @product –> When this happens I need to update a :price attribute..

Anyway of doing this?

Answer 1

class Order
  has_many :products
  def price
    products.sum(:price)
  end
end

Just off the top of my head. Here’s the sum reference:

http://ar.rubyonrails.org/classes/ActiveRecord/Calculations/ClassMethods.html#M000296