title: EF Core One to One or Zero Relationship
body: <p>I have Person and Address. Address is optional.
  Please see below code</p>
  <pre class="lang-cs prettyprint-override"><code>class Person
  {
      [Key]
      public int PersonID { get; set; }
      public string Name { get; set; }
  
      public Address Address { get; set; }
  
  }
  
  class Address
  {
      [Key, ForeignKey(&quot;Person&quot;)]
      public int PersonID { get; set; }
  
      public string City { get; set; }
  }
  </code></pre>
  <p>Registration code is below:</p>
  <pre class="lang-cs prettyprint-override"><code>modelBuilder.Entity&lt;Address&gt;(entity =&gt;
              {
                  entity.HasKey(z =&gt; z.PersonID);
                  entity.HasOne(p =&gt; p.Person)
                       .WithOne(a =&gt; a.Address)
                       .HasForeignKey&lt;Person&gt;(a =&gt; a.PersonId);
              });
  </code></pre>
  <p>How should i change mapping to make Address optionable?</p>