EntityFramework model building - asp.net

Question

I have a class Employee that looks like the following:
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public int Manager { get; set; }
}
I have another class Manager that extends this class and adds no other functionality:
public class Manager : Employee
{
}
In my DbContext derived class I have:
public DbSet<Employee> Employees { get; set; }
public DbSet<Manager> Managers { get; set; }
I want employee's with Employee.Manager == 1 to be added to the Managers DbSet and the employee's with Employee.Manager == 0 to be added to the Employees DbSet.
The database table is structured in this way and I need to be able to do something like this, because I have another class which has a foreign key to an employee and one to a manager.
How can I accomplish this or is there another way to solve my problem?

Answer 1

In order For Code First to use your custom discriminator column, you must modify the default behavior using the Fluent API.
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Employee>()
.Map(e => e.Requires("Manager").HasValue(0))
.Map<Manager>(m => m.Requires("Manager").HasValue(1));
base.OnModelCreating(modelBuilder);
}
A couple things to note:
There is only one DbSet<Employee> in this scenario. A DbSet<Manager> will not work. An Employee retrieved from the database can be identified as a manager by checking the Manager value, and a var manager = new Manager() will automatically be assigned the correct discriminator.
ALL types which inherit from Employee must be given a value for the Discriminator in this modelBuilder. If you skip an inherited class, you will receive runtime errors when accessing any class in the hierarchy.