title: Non primary key Identity AutoIncrement Mapping using Fluent NHibernate
body: <p>I need to manage an additionnal Auto Increment column using Fluent NHibernate.</p>
  
  <p>All my domain classes use Assigned Guid as ID but in a particular entity i need an additionnal auto increment value.</p>
  
  <p>I've tried the following mapping, the column is well created in SQL Server but the Identity Specification isn't set.</p>
  
  <pre><code>        Id(x =&gt; x.OrderId).GeneratedBy.Assigned();
  
          Map(x =&gt; x.TicketNumber).ReadOnly().Generated.Always().Not.Nullable();
  </code></pre>
  
  <p>Any help ?</p>