Doubt about Many-to-Many EF Relationship

Question

I am doubtful in a following rule: I have N Products and N Coins. From this relationship I will have the table Productomoeda:

ProdutoMoeda
Id -  ProdutoId - MoedaID - Nome
1     2           1         ProdutoNome + MoedaNome
2     1           1         ProdutoNome + MoedaNome
3     2           2         ProdutoNome + MoedaNome

I also have a correspondent who markets N Productomoeda. However Correspondent also has N Stores that commercializes the N Productomoeda that is linked to the Correspondent. The store can only sell the products that were registered to the Correspondent, since the store depends on the Correspondent also.

Ex: Correspondent Walmart Trades - Kind Product and Card - in USD and BRL Currencies. Store 1 - which belongs to Correspondent Walmart can only register 1 or N products that Walmart markets.

Would it be right to create a Pk for a table that was generated from an N-N and use as a relationship key in another table? I am trying to represent this in EF also but soon when I will relate Correspondent and Productomoeda using Productoccurforming already generates me some errors. I used the same example to map product and it worked, but to use her relationship with product:

ProdutoCorrespondente_ProdutoMoeda_Target_ProdutoCorrespondente_ProdutoMoeda_Source: : The number of properties in the Dependent and Principal Roles in a relationship constraint must be identical.

The map is like this:

public ProdutoCorrespondenteConfig()
    {

        HasKey(x => new { x.ProdutoCorrespondenteId, x.ProdutoMoedaId, x.CorrespondenteId });

        Property(x => x.ProdutoCorrespondenteId)
            .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

        Property(t => t.Nome)
           .IsRequired()
           .HasMaxLength(60);

        HasRequired(x => x.ProdutoMoeda)
            .WithMany(x => x.ProdutosCorrespondente)
            .HasForeignKey(x => x.ProdutoMoedaId);

        HasRequired(x => x.Correspondente)
            .WithMany(x => x.ProdutosCorrespondente)
            .HasForeignKey(x => x.CorrespondenteId);

    }

Answer 1

It would be right to create a Pk for a table that was generated from an N-N and use as a relationship key in another table?

Yeah, but that’s not how you’re gonna get it:

HasKey(x => new { x.ProdutoCorrespondenteId, x.ProdutoMoedaId, x.CorrespondenteId });

The recommended modeling is like this:

public class ProdutoCorrespondente
{
    [Key]
    public int ProdutoCorrespondenteId { get; set; }
    [Index("IUQ_ProdutoCorrespondente_ProdutoMoedaId_CorrespondenteId", IsUnique = true, Order = 1)]
    public int ProdutoMoedaId { get; set; }
    [Index("IUQ_ProdutoCorrespondente_ProdutoMoedaId_CorrespondenteId", IsUnique = true, Order = 2)]
    public int CorrespondenteId { get; set; }

    [Required]
    [StringLength(60)]
    public String Nome { get; set; }

    public virtual ProdutoMoeda ProdutoMoeda { get; set; }
    public virtual Correspondente Correspondente { get; set; }
}