title: cannot update identity column in Entity Framework Core
body: <p>I've added a separate Identification to the AspNetUsers table called NumericId that will serve along with the GUID like ID that ASP has for default.</p>
  
  <p>I've added the property as an additional property of the ApplicationUser class:</p>
  
  <pre><code>public class ApplicationUser : IdentityUser
  {
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      public virtual int NumericId { get; set; }
  }
  </code></pre>
  
  <p>However, when I try to register, or update the user's details (that aren't even relevant to the numericId) I keep getting the error </p>
  
  <pre><code>SqlException: Cannot update identity column 'NumericId'.
  </code></pre>
  
  <p>which prevents any changes and in the end does not update the user (but it does register one, and Numeric Id is properly assigned on that part. But this is irrelevant)</p>