Heyyy :)

I am searching for a solution a few hours ago, but i dont find some... so I hope, you can help me :)
I get a Database with 2 different table, the first is teacher and the second is student. The programm should controll at the logIn the email- adresses and should knew, if the person is a teacher or a student.
If I only work with one table, my function starts, but if I activated both, it didn´t debbug :(
I post my Code, which shows mistakes and I hope you can help me :)

public ActionResult LogOn(UserViewModel model)
{

if (string.IsNullOrEmpty(model.EMail) || string.IsNullOrEmpty(model.Password))
return View();

//Have I to do a JOIN??

Teacher teacher = NHibernateSession.QueryOver<Teacher>().Where(x => x.EMail == model.EMail).List().ToList().First();
Student student = NHibernateSession.QueryOver<Student>().Where(x => x.EMail == model.EMail).List().ToList().First();


if (model.EMail == student.EMail && model.Password == student.Password)
{
FormsAuthentication.SetAuthCookie(model.EMail, false);
return RedirectToAction("Index", "Student");
}

regrads,
Elma