title: Foreign key constraint issue?
body: <p>I've made some changes to my EF code first database and when I try to update it I now get the following error:</p>
  
  <p><strong>Introducing FOREIGN KEY constraint 'FK_dbo.SupportTicketMessages_dbo.SupportTickets_Ticket_Id' on table 'SupportTicketMessages' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.</strong></p>
  
  <p>Here are my entities:</p>
  
  <p>SupportTicket:</p>
  
  <pre><code>public class SupportTicket
      {
          [Key]
          [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
          public int Id { get; set; }
  
          [Required]
          public string Title { get; set; }
  
          [Required]
          public string Text { get; set; }
  
          [Required]
          public TicketUrgency Urgency { get; set; }
  
          [Required]
          public TicketStatus Status { get; set; }
  
          [Required]
          public virtual UserProfile Owner { get; set; }
  
          [Required]
          public DateTime Date { get; set; }
  }
  </code></pre>
  
  <p>SupportTicketMessage:</p>
  
  <pre><code>public class SupportTicketMessage
      {
          [Key]
          [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
          public int Id { get; set; }
  
          [Required]
          public virtual UserProfile Author { get; set; }
  
          [Required]
          public string Text { get; set; }
  
          [Required]
          public DateTime Date { get; set; }
  
          [Required]
          public virtual SupportTicket Ticket { get; set; }
  
          [Required]
          public int MessageNumber { get; set; }
      }
  </code></pre>
  
  <p>What's the issue here? I don't see what's wrong.</p>