title: EF Core cannot insert the value null into column with default value
body: <p>I have entity</p>
  
  <pre><code>public class Realtor
  {
      [Key]
      public int Id { get; set; }
  
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      public Guid Guid { get; set; }
  
      public string FirstName { get; set; }
      public string LastName { get; set; }
  
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      public DateTime Registration { get; set; }
  
      [ForeignKey("Id")]
      public int SubdivId { get; set; }
      public Subdiv Subdiv { get; set; }
  }
  </code></pre>
  
  <p>and context with OnModelCreating method</p>
  
  <pre><code>modelBuilder.Entity&lt;Realtor&gt;(real =&gt; {
              real.Property&lt;Guid&gt;(p =&gt; p.Guid)
              .HasDefaultValueSql("newsequentialid()");
  
              real.Property&lt;DateTime&gt;(p =&gt; p.Registration)
              .HasDefaultValueSql("getdate()");
  
              real.HasOne(r =&gt; r.Subdiv)
              .WithMany(s =&gt; s.Realtors)
              .HasForeignKey(r =&gt; r.SubdivId);
          });
  </code></pre>
  
  <p>I set default value for property Registration, but when I do an insert, I get Exception: cannot insert the value null into column Registration.</p>