Activity Description

Create a migration that copies the product price into the line item, and add_product method in the Cart model to capture the price whenever a new line item is created.

Author’s Solutions

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Readers’ Solutions blah

Marius says

The migration first: rails generate migration add_product_price_to_line_item price:decimal

class AddProductPriceToLineItem < ActiveRecord::Migration
  def self.up
    add_column :line_items, :price, :decimal, :precision => 8, :scale => 2
  end

  def self.down
    remove_column :line_items, :price
  end
end

In cart.rb

<code>
  def add_product(product_id, product_price)
    current_item = line_items.where(:product_id => product_id).first
    if current_item
      current_item.quantity += 1
    else
      current_item = LineItem.new(:product_id => product_id, :price => product_price)
      line_items << current_item
    end
    current_item
  end
</pre>
</code