为什么NHibernate更新参考实体？

我有一个测试评判象下面这样：为什么NHibernate更新参考实体？

 public void Add_Update_Delete_a_Registration() { 

     ISessionFactory sessionFactory = SessionFactory.GetSessionFactory(connString); 
     using (ISession session = sessionFactory.OpenSession()) { 

      Course course = new CourseRepository(session).GetById(12019); 

      Registration entity = new Registration(); 
      entity.Course = course; //Assign the Course to register 

      //assign other entity members 
      //... 

      RegistrationRepository repository = new RegistrationRepository(session); 
      repository.Add(entity); 
     }

注册实体被正确插入。

问题是，NHibernate也做了UPDATE数据库调用来更新课程实体，它在测试方法中根本没有改变。可能的原因是什么？

的映射：

public class CourseMap : ClassMap<Course>{ 
    public CourseMap() { 
     Id(x => x.Id).GeneratedBy.HiLo("100"); 
     Map(x => x.WeekDay) 
      .Not.Nullable() 
      .CustomType<int>(); //WeekDay is type of DayOfWeek enums 
     References(x => x.Room) 
      .Not.Nullable(); 
     Map(x => x.StartTime) 
      .Not.Nullable(); 
     Map(x => x.EndTime) 
      .Not.Nullable(); 
     Map(x => x.CreatedTime) 
      .Not.Nullable(); 
     Map(x => x.UpdatedTime); 
     Map(x => x.CreatedBy) 
      .Not.Nullable(); 
     Map(x => x.UpdatedBy); 
     Version(x => x.Version).Column("RCB_Version") 
      .CustomSqlType("timestamp") 
      .Generated.Always() 
      .Not.Nullable(); 
    } 

    public class RegistrationMap : ClassMap<Registration>{ 
    public RegistrationMap() { 
     Id(x => x.Id) 
      .GeneratedBy.HiLo("100"); 
     Map(x => x.OwnerWindowsAccount) 
      .Not.Nullable() 
      .Length(50); 
     References(x => x.Course) 
      .Not.Nullable(); 
     Map(x => x.TrainingDate) 
      .Not.Nullable(); 
     Map(x => x.RegistreeName) 
      .Not.Nullable() 
      .Length(50); 
     Map(x => x.RegistreeWindowsAccount) 
      .Nullable() 
      .Length(50); 
     Map(x => x.CreatedTime) 
      .Not.Nullable(); 
     Map(x => x.UpdatedTime); 
     Map(x => x.CreatedBy) 
      .Not.Nullable(); 
     Map(x => x.UpdatedBy); 
     Version(x => x.Version) 
      .CustomSqlType("timestamp") 
      .Generated.Always() 
      .Not.Nullable(); 
    } 
}

非常感谢！狮子座

来源

2011-11-30 user538220