实体框架一对多与每个层次的每个子类创建一个外键列

我有一个 Garage ，其中包含 Cars 和摩托车。汽车和摩托车是车辆。这里是：

I have a Garage which contains Cars and Motorcycles. Cars and motorcycles are Vehicles. Here they are:

public class Garage
{
    public int Id { get; set; }
    public virtual List<Car> Cars { get; set; }
    public virtual List<Motorcycle> Motorcycles { get; set; }

    public Garage()
    {
        Cars = new List<Car>();
        Motorcycles = new List<Motorcycle>();
    }
}

public abstract class Vehicle
{
    public int Id { get; set; }
    public string Make { get; set; }
    public string Model { get; set; }
}

public class Car : Vehicle
{
    public int GarageId { get; set; }
    public virtual Garage Garage { get; set; }
    // some more properties here...
}

public class Motorcycle : Vehicle
{
    public int GarageId { get; set; }
    public virtual Garage Garage { get; set; }
    // some more properties here...
}

为什么汽车和摩托车每个都有一个GarageId和Garage属性？如果我把这些属性推到车辆超类，EF会抱怨告诉我导航属性必须位于具体的类中。

Why do Car and Motorcycle each have a GarageId and Garage property? If I push those properties up to the Vehicle superclass, EF complains and tells me navigation properties must reside in concrete classes.

继续，这里是我的DbContext：

Moving on, here's my DbContext:

public class DataContext : DbContext
{
    public DbSet<Garage> Garages { get; set; }
    public DbSet<Vehicle> Vehicles { get; set; }
    public DbSet<Car> Cars { get; set; }
    public DbSet<Motorcycle> Motorcycles { get; set; }

    public DataContext()
        : base("GarageExample")
    {

    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
        modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();
    }
}

这是一个简短的程序来玩我的玩具：

And here's a short program to play with my toys:

class Program
{
    static void Main(string[] args)
    {
        Database.SetInitializer<DataContext>(new DropCreateDatabaseAlways<DataContext>());

        using (var db = new DataContext())
        {
            var car1 = new Car { Make = "Subaru", Model = "Legacy" };
            var car2 = new Car { Make = "Porche", Model = "911" };

            var bike1 = new Motorcycle { Make = "Suzuki", Model = "GS500" };
            var bike2 = new Motorcycle { Make = "Kawasaki", Model = "Ninja" };

            var garage = new Garage();

            garage.Cars.Add(car1);
            garage.Cars.Add(car2);
            garage.Motorcycles.Add(bike1);
            garage.Motorcycles.Add(bike2);

            db.Garages.Add(garage);

            db.SaveChanges();
        }
    }
}

程序运行并生成以下车辆表：

The program runs, and produces the following Vehicles table:

Id Make     Model  GarageId GarageId1 Discriminator
1  Subaru   Legacy 1        null      Car
2  Porche   911    1        null      Car
3  Suzuki   GS500  null     1         Motorcycle
4  Kawasaki Ninja  null     1         Motorcycle

汽车和摩托车都有自己的GarageId和Garage属性，似乎每个子类都在创建自己的外挂车库。如何可以告诉EF（如果可能，通过流畅的api）Car.Garage和Motorcycle.Garage是一样的，应该使用相同的列？

With both Car and Motorcycle having their own GarageId and Garage properties, it seems that each subclass is creating its own foreign key to garage. How do I tell EF (via the fluent api, if possible) that Car.Garage and the Motorcycle.Garage are the same thing, and should use the same column?

这是我想要的车辆表：

Id Make     Model  GarageId Discriminator
1  Subaru   Legacy 1        Car
2  Porche   911    1        Car
3  Suzuki   GS500  1        Motorcycle
4  Kawasaki Ninja  1        Motorcycle