title: Having a List<T>, how can I get other fields from DB?
body: <p>I have a method named <code>GetOrders</code>. This method reads an XML file and gathers <code>OrderNumber</code> of  all orders related to a specific user. The method returns a <code>list&lt;string&gt;</code>.</p>
  
  <p>Now I want to know, having my list, how can I get other fields of these OrderNumbers from DB?</p>