Entity framework 5 many to many when an entity is using composite key

Question

im having some problems with EF 5 when i want to map many to many relationships using code first. This is my scenario:

public class SegFunction
{
    public virtual string Idaplication {get;set;}

    public virtual string Idfunction {get;set;}

    public virtual List<SegRole> Roles { get; set; }

}

public class SegRole
{
    public virtual int Idrole { get; set; }

    public virtual List<SegFunction> Functions { get; set; }

}

This are my maps:

private void MapSegRole()
    {
        this.modelBuilder.Entity<SegRole>()
        .Map(entity =>
        {
            entity.ToTable("seg_roles");
        });
        this.modelBuilder.Entity<SegRole>()
            .Property(t => t.Idrole).HasColumnName("id_role");
        this.modelBuilder.Entity<SegRole>()
             .HasKey(c => c.Idrole);


        modelBuilder.Entity<SegRol>()
       .HasMany(i => i.Functions)
       .WithMany(c => c.Roles)
       .Map(
        m =>
        {
            mc.ToTable("seg_role_function");
            m.MapRightKey("id_role");
            m.MapLeftKey("id_aplication");
            m.MapLeftKey("id_function");
        });
    }

And

private void MapSegFunction()
    {

        this.modelBuilder.Entity<Segfunction>()
        .Map(entity =>
        {
            entity.ToTable("seg_functions");
        });
        this.modelBuilder.Entity<Segfunction>()
            .Property(t => t.Idfunction).HasColumnName("id_function");
        this.modelBuilder.Entity<Segfunction>()
            .Property(t => t.Idaplication).HasColumnName("id_aplication");
        this.modelBuilder.Entity<Segfuncion>()
            .HasKey( d => new { d.Idaplication, d.Idfunction});

        this.modelBuilder.Entity<Segfunction>()
           .HasMany(t => t.Roles)
           .WithMany(r => r.Functions)
            .Map(mc =>
            {
                mc.ToTable("seg_role_function");
                mc.MapLeftKey("id_role");
                mc.MapRightKey("id_aplication");
                mc.MapRightKey("id_function");
            });





    }

I have three tables Seg_Role, Seg_Function, Seg_role_function where seg_function has composite primary key (id_aplication, id_function) and seg_role_function has a composite key (id_role, id_aplication, id_function)

i'm getting the following error when i try to get from context:

The specified association foreign key columns 'id_role' are invalid. The number of columns specified must match the number of primary key columns.

score 8 · Accepted Answer · answered Jun 14 '13 at 00:26

8

MapLeftKey and MapRightKey have a params string[] keyColumnNames parameter, so for composite keys you pass in multiple parameters into those methods instead of calling them twice:

modelBuilder.Entity<SegRol>()
   .HasMany(i => i.Functions)
   .WithMany(c => c.Roles)
   .Map(m =>
    {
        mc.ToTable("seg_role_function");
        m.MapLeftKey("id_role");
        m.MapRightKey("id_aplication", "id_function");
    });

answered Jun 14 '13 at 00:26

Slauma

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1

@DiegoGomez: Can you try it with *exactly* my mapping above? Only in `MapSegRole` and remove the second many-to-many mapping in `MapSegFunction`, it is redundant. In your mapping `...Left...` and `...Right...` are wrong, it must be the other way around. – Slauma Jun 14 '13 at 00:37
1

Yeah, it works! Thank you very much, this problem was driving me crazy! – Diego Gomez Jun 14 '13 at 00:42
1

Did you mean `m.ToTable` instead of `mc.ToTable` ? – Tsagana Nokhaeva Mar 29 '18 at 09:44

Entity framework 5 many to many when an entity is using composite key

1 Answers1