与单表实体框架asp.net MVC的多个关系

Question

I've just started using Entity Framework for my next project and I'm struggling with the following. I have the following ApplicationUser class:

public class ApplicationUser : IdentityUser 
{
    public string Name { get; set; }
    public int CompanyId { get; set; }
    public virtual Company Company { get; set; }
}

I have two classes that inherent from this class:

public class TrainerUser : ApplicationUser  
{
    public virtual ICollection<ClientUser> Clients { get; set; }
}

public class ClientUser : ApplicationUser 
{
    public string TrainerId { get; set; }
    public TrainerUser Trainer { get; set; }
}

The company class looks like this:

public class Company 
{
    public int Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<TrainerUser> Trainers { get; set; }
    public virtual ICollection<ClientUser> Clients { get; set; }
}

What I can't figure out is how I can use the fluent API to not include 3 different companyId columns in the ApplicationUsers table.

Currently I have the following fluent API configuration:

modelBuilder.Entity<TrainerUser>().HasRequired(c => c.Company).WithMany(t => t.Trainers).HasForeignKey(c => c.CompanyId);
modelBuilder.Entity<ClientUser>().HasRequired(c => c.Company).WithMany(c => c.Clients).HasForeignKey(c => c.CompanyId);

Can anyone point me in the right direction?

Answer 1

Try adding these to your code.

modelBuilder.Entity<TrainerUser>().ToTable("TrainerUser");
modelBuilder.Entity<ClientUser>().ToTable("ClientUser");

If I am getting you right. you are trying to create a structure representing Table Per Hierarchy (TPT) . Read more about it at the link.

Basically what happens is when entity framework encounters inheritance in the entities. Its Default attempt to create tables is by creating column of the set of all properties of all the derived entities from a class with a discriminator column.

What you are trying to create is a separate table for every class in the hierarchy.