Selecting Data directly vs using navigation property in EF - asp.net-mvc

Question

Hi there in a MVC application I have the following sample POCO classes(Actual application has 10-15 screens for employee data). Manager has many employees and he can update their personal and contact details. I am considering 3 approaches to retrieve the current employee data from database using EF.
1) When manager select an employee, store EmployeeId in Session (Session["currentEmp"]) and use this EmployeeId to get the data for the current employee.
like:
int employeeId = (int)Session["currentEmp"];
EmployeeContactDetails1 empCtDet1 = ctx.EmployeeContactDetails1.Find(employeeId);
then
EmployeeContactDetails2 empCtDet2 = ctx.EmployeeContactDetails2.Find(employeeId);
2) Have a discriminator property such as "unlocked" on Employee class and when manager select the employee then mark it unlocked = true and update the column in database and the do something like this for further data retrieval
EmployeeContactDetails1 empCtDet1 = ctx.Employees.Where(e => e.unlocked == true).EmployeeContactDetails1;
EmployeeContactDetails2 empCtDet2 = ctx.Employees.Where(e => e.unlocked == true).EmployeeContactDetails2;
3) Or
EmployeeContactDetails1 empCtDet1 = ctx.EmployeeContactDetails1.Where(e => e.Employee.unlocked == true).FirstOrDefault();
EmployeeContactDetails2 empCtDet2 = ctx.EmployeeContactDetails2.Where(e => e.Employee.unlocked == true).FirstOrDefault();
I would like to ask you which one is better keeping in mind security and performance.
public class Manager{
public int ManagerId{get;set;}
public string ManagerName{get;set;}
public string someMoreProp{get;set;}
public ICollection<Employee>Employee{get;set;}
}
public class Employee{
public int EmployeeId{get;set;}
public virtual EmployeePersonalDetails EmployeePersonalDetails{get;set;}
public virtual EmployeeContactDetails EmployeeContactDetails{get;set;}
public int ManagerId{get;set;}
public virtual Manager Manager{get;set;}
}
public class EmployeePersonalDetails{
public int EmployeeId{get;set;}
public string Name{get;set;}
public string Age{get;set;}
public Address AddressOne{get;set;}
public Employee Employee{get;set;}
}
public class EmployeeContactDetails1{
public int EmployeeId{get;set;}
public string Line1{get;set;}
public string Line2{get;set;}
public Employee Employee{get;set;}
}
public class EmployeeContactDetails2{
public int EmployeeId{get;set;}
public string Line1{get;set;}
public string Line2{get;set;}
public Employee Employee{get;set;}
}
public class EmployeeContactDetails3{
public int EmployeeId{get;set;}
public string Line1{get;set;}
public string Line2{get;set;}
public Employee Employee{get;set;}
}
public class EmployeeContactDetails4{
public int EmployeeId{get;set;}
public string Line1{get;set;}
public string Line2{get;set;}
public Employee Employee{get;set;}
}

Answer 1

First, don't use Session. The mentioned way you're considering is a completely unacceptable use of sessions. A well-designed web app will as much as feasibly possible avoid sessions like the plague. The notable exception is of course authentication, which can't be achieved in a user-friendly way by any other means.
Second, in general, you seem to be making this far too complicated. It's not entirely clear what you're trying to achieve, but it sounds like you simply want the manager to be able to do something like click on an employee and then be taken to a view where they can edit that employee's details. The correct way to do that is to have a dedicated URI, consisting of the employee id or some other uniquely identifying token. For example:
/employees/{id}/edit
Then, in the action that that URI routes to, you would use the id param to look up the employee:
var employee = db.Employees.Find(id);
if (employee == null)
{
return new HttpNotFoundResult();
}
Since, presumably, you would only want the manager of that employee to be able to edit the employee, you would simply do object-level authorization by including the manager's id in the query:
var managerId = User.Identity.GetUserId(); // currently logged in manager
var employee = db.Employees.SingleOrDefault(m => m.EmployeeId == id && m.ManagerId == managerId);