title: Can I use a datetime as a key using code-first entity framework with mvc 4?
body: <p>I am trying to represent a workday as a class in c#/table in a database for an ASP.NET MVC 4 application. I want to use code-first entity framework. When I  try to add a controller for the workday I get an error that it has to have a key/identity. I know I can just add an <code>int ID</code> field to make the error go away--but is there any way to tell the entity framework to use 
   <code>DayOfWork</code> as the PK? That sems the cleanest way to respresent this in a database. The day <em>should</em> be the PK.</p>
  
  <pre><code>namespace TimeKeeper.Models
  {
      public class WorkDay
      {
          public DateTime DayOfWork { get; set; }
          public Boolean holiday { get; set; } 
      }
  }
  </code></pre>