首先在同一张表中启用Entity Framework 5代码中的多对多

Question

I am new to Entity Framework. I am using Version 5 code first.

I have a model:

class RebateBase
{
    public int ID { get; set; }

    public RebateType RebateType { get; set; }

    public virtual ICollection<Customer> Customers { get; set; }

    public virtual ICollection<TurnoverClassification> AvailableTurnoverClassifications { get; set; }

    public virtual ICollection<TurnoverClassification> EnabledTurnoverClassifications { get; set; }


    public RebateBase()
    {
        if (AvailableTurnoverClassifications == null)
        {
            AvailableTurnoverClassifications = new List<TurnoverClassification>();
        }

        if (EnabledTurnoverClassifications == null)
        {
            EnabledTurnoverClassifications = new List<TurnoverClassification>();
        }

        if (Customers == null)
        {
            Customers = new List<Customer>();
        }
    }

and a model

class TurnoverClassification
{
    public string Name { get; set; }

    public virtual ICollection<RebateBase> RebateBases{ get; set; }

    [Key]
    public int NumericalValue { get; set; }
}

I already tried to initialize data with and without

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();


        modelBuilder.Entity<RebateBase>()
            .HasMany<TurnoverClassification>(rb => rb.AvailableTurnoverClassifications)
            .WithMany(tc => tc.RebateBases)
            .Map(rt =>
                {
                    rt.MapLeftKey("RebateID");
                    rt.MapRightKey("TurnoverID");
                    rt.ToTable("RebateBase_AvailableTurnoverClassifications");
                });

        modelBuilder.Entity<RebateBase>()
            .HasMany<TurnoverClassification>(rb => rb.EnabledTurnoverClassifications)
            .WithMany(tc => tc.RebateBases)
            .Map(rt =>
            {
                rt.MapLeftKey("RebateID");
                rt.MapRightKey("TurnoverID");
                rt.ToTable("RebateBase_EnabledTurnoverClassifications");
            });

But it doesn't work. With the upper approach I get the error:

Schema specified is not valid. Errors: (9,6) : error 0040: Type RebateBase_AvailableTurnoverClassifications is not defined in namespace CustomerConfiguration.Datalayer (Alias=Self).

When I remove the second navigation property enabledturnoverClassifications everythings is fine and I don't need to adapt the mapping in modelbuilder. As soon as I add the second navigationproperty I get the error.

Could anybody please help?

Thank you.

Greetz

Harry

Answer 1

You can use the InverseProperty attribute to specify the corresponding collection in the TurnoverClassification class to enable multiple many to many relationships. The answer to this contains an example of multiple many to many relationships in EF.

I tested this with a Enable-Migrations specified and the correct relation tables were created.

class RebateBase
{
    public int ID { get; set; }

    public RebateType RebateType { get; set; }

    public virtual ICollection<Customer> Customers { get; set; }

    [InverseProperty("RebateBasesAvailable")]
    public virtual ICollection<TurnoverClassification> AvailableTurnoverClassifications { get; set; }

    [InverseProperty("RebateBasesEnabled")]
    public virtual ICollection<TurnoverClassification> EnabledTurnoverClassifications { get; set; }


    public RebateBase()
    {
        if (AvailableTurnoverClassifications == null)
        {
            AvailableTurnoverClassifications = new List<TurnoverClassification>();
        }

        if (EnabledTurnoverClassifications == null)
        {
            EnabledTurnoverClassifications = new List<TurnoverClassification>();
        }

        if (Customers == null)
        {
            Customers = new List<Customer>();
        }
    }

The model

class TurnoverClassification
{
    public string Name { get; set; }

    public virtual ICollection<RebateBase> RebateBasesAvailable{ get; set; }
    public virtual ICollection<RebateBase> RebateBasesEnabled{ get; set; }

    [Key]
    public int NumericalValue { get; set; }
}