title: Database - Should total price be stored in a column?
body: <p>I have <code>orders</code> and <code>items</code> table. Here's the association</p>
  
  <pre><code># order.rb
  has_many :items
  
  # item.rb
  belongs_to :order
  </code></pre>
  
  <p>What I'm wondering is: Should I keep the total price in the order table? The total price is summed from each item.</p>
  
  <p>I need to generate <strong>Chart</strong> and the only data needed is the total price.</p>
  
  <p>My app is still on local development so I haven't had any performance issue. But I'm guessing it will start having an impact after there are few hundreds of orders.</p>