title: How can I have value types that map to nullable database columns in Entity Framework?
body: <p>I have the following Entity model:</p>
  
  <pre><code>public class Todo  
  {  
      [Required]  
      public int ID { get; set; }  
      public int OrderId { get; set; } //Not required  
      public string Description { get; set; }  
      public bool Finished { get; set; }  
      public DateTime CreationDate { get; set; }  
      public int Priority { get; set; } //Not required  
      public string CreatedBy { get; set; }  
      public bool Deleted { get; set; }  
  }
  </code></pre>
  
  <p>In the corresponding database table all of the fields are created as "not null". I want to allow some of the fields to be null. How do I do this?</p>