title: Why `DatabaseGenerated(DatabaseGeneratedOption.Identity)` doesn't work in MVC 4
body: <p>I was trying to move my MVC 3 project to MVC 4 but when I wanted to move this model:</p>
  
  <pre><code>public class Link
  {
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      public Guid ID { get; set; }
  
      [DisplayName("Shorted URL")]
      public string SURL { get; set; }
  
      [DisplayName("General Link")]
      public string OriginalURL { get; set; }
  
      [DisplayName("Click Count")]
      public int ClickCount { get; set; }
  }
  
  public class LinkDBContext : DbContext
  {
      public DbSet&lt;Link&gt; Links { get; set; }
  }
  </code></pre>
  
  <p>I got error with <code>[System.ComponentModel.DataAnnotations.(DatabaseGeneratedOption.Identity)]</code> attribute. I don't know what's the problem. Does anyone know?!?</p>
  
  <p><strong>Update</strong></p>
  
  <p>These are the errors:</p>
  
  <blockquote>
    <p>The type or namespace name 'DatabaseGeneratedAttribute' could not be
    found (are you missing a using directive or an assembly reference?)</p>
    
    <p>The type or namespace name 'DatabaseGenerated' could not be found (are
    you missing a using directive or an assembly reference?)</p>
  </blockquote>