EF Core Code First, 2 Many to one relations of same object

Question

I have 2 classes like with the following structure, Person has 2 many-one relations with SchoolClass:

public class Person
    {
        public int Id { get; set; }
        public List<SchoolClass> SchoolClasses { get; set; }
        public List<SchoolClass> OldSchoolClasses { get; set; }
    }

    public class SchoolClass
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

I can add ghostProps but can't change the classes.

When I make a migration for EFCore, it adds 2 different Person Id's to the SchoolClass table which I want to avoid.

I want to generate 2 many to many tables instead:

• PersonSchoolClasses Table
• OldPersonSchoolClasses Table

Is this possible with Fluent API?

Answer 1

Perhaps you should try inheritance:

public class SchoolClass    // this could be abstract
{
    public int Id { get; set; }
    public string Name { get; set; }
}
public class NewSchoolClass : SchoolClass
{
}
public class OldSchoolClass : SchoolClass
{
}
public class Person
{
    public int Id { get; set; }
    public IList<NewSchoolClass> NewSchoolClasses { get; set; }
    public IList<OldSchoolClass> OldSchoolClasses { get; set; }
}

And in DbContext:

-DbSet<SchoolClass> SchoolClasses { get; set; }
+DbSet<OldSchoolClass> OldSchoolClasses { get; set; }
+DbSet<NewSchoolClass> NewSchoolClasses { get; set; }