One class per navigation property

Question

I am trying to add EF6.4 to an existing code base (and removing NHibernate). One of the tables is referenced by multiple other tables.

I have used Entity Framework 6.4 to reverse engineer classes for me (code-first style, with no designer).

For this particular table it produces code like this:

[Table("MyTable")]
public partial class MyTable
{
    public Guid Id { get; set; }
    public string Field1 { get; set; }
    public string Field2 { get; set; }

    // Navigation properties
    public virtual TypeA A { get; set; }
    public virtual TypeB B { get; set; }
    public virtual TypeC C { get; set; }
}

I would rather (to match existing NHibernate code) have MyTable be 3 classes with 1 navigation property each (MyTableA, MyTableB, MyTableC):

[Table("MyTable")]
public partial class MyTableA
{
    public Guid Id { get; set; }
    public string Field1 { get; set; }
    public string Field2 { get; set; }

    // Navigation properties
    public virtual TypeA A { get; set; }
}

[Table("MyTable")]
public partial class MyTableB
{
    public Guid Id { get; set; }
    public string Field1 { get; set; }
    public string Field2 { get; set; }

    // Navigation properties
    public virtual TypeB B { get; set; }
}

[Table("MyTable")]
public partial class MyTableC
{
    public Guid Id { get; set; }
    public string Field1 { get; set; }
    public string Field2 { get; set; }

    // Navigation properties
    public virtual TypeC C { get; set; }
}

How can I accomplish this? (Having the fields in a base class is perfectly ok). I can not change the database for this.

Answer 1

As i know entity framework does not have possibility in dataContext add 3 classes as one table.But you can make projection to three classes.So your code will looks like

[Table("MyTable")]
public partial class MyTable
{
    public Guid Id { get; set; }
    public string Field1 { get; set; }
    public string Field2 { get; set; }

    // Navigation properties
    public virtual TypeA A { get; set; }
    public virtual TypeB B { get; set; }
    public virtual TypeC C { get; set; }
}

so your db context class should have property

public MyDbContext: : DbContext
{
    public virtual DbSet<MyTable> MyTable{ get; set; }
}

than you can add your projection classes

public class BaseTable
{
    public Guid Id { get; set; }
    public string Field1 { get; set; }
    public string Field2 { get; set; }
}

public class MyTableA: BaseTable
{
    // Navigation properties
    public virtual TypeA A { get; set; }
}

Than you can add base query projection in your repository

   public class MyTableRepository 
        {
          private IQueryable<MyTableA> tableAEntities;
          public MyTableRepository(MyDbContext  dbContext) 
          {
              tableAEntities = dbContext.MyTable.Select(t => 
                 new MyTableA 
                {
                 Id = t.Id, 
                 Field1 = t.Field1, 
                 Field2 = t.Field2, 
                 A = t.A 
                });
          }
        }