EF Code First Muliple Inheritance is exclusive? - entity-framework

Question

Let's say I have a model where I have the Person entity with general info (Names, Date of Birth, etc.), and two additional entities (Customer, Worker) which inherit from Person. As you see there is the option of having a Customer who CAN ALSO play the role of a Worker in the model. There is a way to design this in EF (I saw something about TPH, TPT and TPC) but I see that there is a use of discriminator which doesn't allow a Person table to include values for Worker and Customer "simultaneously".
I don't know if maybe I'm getting wrong with the general OOP concept of inheritance :S.
Thanks in advance for all your help.

Answer 1

You cant have multiple inheritance in .net, it is not supported (and the same applies to entity framework). You can implement multiple interfaces, but this is a slightly different notion - i.e. 'Worker' could be an interface that is implemented by some objects, such as customer
In entity framework, I believe that the discriminator is only implemented when using Table-per-hierarchy. This is where both child entities are stored in the same table, and the discriminator identifies which is which.
Table-per-type is essentially where the entities (person, customer, worker) are stored in different tables, but are accessible as single entities in your code (i.e. customer with an inheritance from person)
It may be that you need to create an interface (maybe IWorker), and create a class (maybe WorkerCustomer??) that inherits from Customer, and implements IWorker.
EDIT: 15/02/2013 19:00
Ok, so the below might be what you're looking for in terms of representing the data in a single table:
public class MyDbContext : DbContext
{
public MyDbContext() : base("TestDB")
{
}
public DbSet<Person> People { get; set; }
public DbSet<Customer> Customers { get; set; }
public DbSet<Worker> Workers { get; set; }
public DbSet<WorkerCustomer> WorkerCustomers { get; set; }
}
public class Person
{
public int ID { get; set; }
public string Name { get; set; }
}
public class Customer : Person
{
public string CustomerNumber { get; set; }
}
public interface IWorker
{
string WorkerNumber { get; set; }
}
public class Worker : Person, IWorker
{
public string WorkerNumber { get; set; }
}
public class WorkerCustomer : Customer
{
public string WorkerNumber { get; set; }
}