title: A dependent property in a ReferentialConstraint is mapped to a store-generated column error on 1-to-1 relationship
body: <p>In EntityFramework code first models, there exists a 1:1 relationship:</p>
  
  <pre><code>public class Child1
  {
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      public int Id { get; set; }
  
      public string Name { get; set; }
  
      public Child2 Child2 { get; set; }
  }
  
  public class Child2
  {
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      [ForeignKey("Child1")]
      public int Id { get; set; }
  
      public string Name { get; set; }
  
      public Child1 Child1 { get; set; }
  }
  </code></pre>
  
  <p>When I tried to insert some data to the database, it thrown an exception:</p>
  
  <pre><code>{"A dependent property in a ReferentialConstraint is mapped to a 
    store-generated column. Column: 'Id'."}
  </code></pre>
  
  <p>It seems I cannot use auto generated Id for <code>Child2</code>, how can I keep this feature and make the relationship established successfully meanwhile?</p>