Error on saveChanges() in MVC

I am doing insertion operation in MVC with Code first approach:

My Model class:

public class RegUsers1

{

[key]

public int Uid { set; get; }

public string FullName { set; get; }

public string Email { set; get; }

public string Password { set; get; }

public string Gender { set; get; }

public string Qualification { set; get; }

}

In my controller:

[HttpPost]

public ActionResult Register(RegUsers u)

{

db.Users.Add(u);

db.SaveChanges();

return RedirectToAction("Home");

}

while inserting it is throwing an error as:

"An error occurred while updating the entries. See the inner exception for details. "

Please solve it friends.