title: EF Code First - Fluent API (WithRequiredDependent and WithRequiredPrincipal)
body: <p><strong>I have the following class:</strong></p>
  
  <pre><code>public class User
  {
      public Guid Id { get; set; }
      public string Name { get; set; }
      public Couple Couple { get; set; }
  }
  
  public class Couple
  {
      public Guid Id { get; set; }
      public User Groom { get; set; }
      public User Bride { get; set; }
  }
  </code></pre>
  
  <p><strong>Important points:</strong></p>
  
  <ol>
  <li><code>Bride</code> and <code>Groom</code> properties are required</li>
  <li>One-to-one relationship</li>
  <li>In the <code>User</code> class, it is <code>Couple</code> required</li>
  </ol>
  
  <p><strong>DbContext in OnModelCreating</strong></p>
  
  <pre><code>modelBuilder.Entity&lt;User&gt;().HasRequired(u =&gt; u.Couple).WithRequiredPrincipal();
  modelBuilder.Entity&lt;Couple&gt;().HasRequired(u =&gt; u.Bride).WithRequiredDependent();
  modelBuilder.Entity&lt;Couple&gt;().HasRequired(u =&gt; u.Groom).WithRequiredDependent();
  </code></pre>
  
  <p>But I can not be required!</p>
  
  <p>All fileds are with null in the database!.</p>
  
  <p>How do I get the fields in the database as not null?
  <strong>If possible using the API Flient</strong>.</p>