Agfdhyk

I have the following problem:

I have a company (CW_Firma) which can have 0 to many ways to contact them (CW_FirmaCommunication).
I am using EntityFramework and FluentAPI to create the relationship.

I have the following code :

[Table("dbo.CW_Firma")]

public class CW_Firma

{

    [Key]

    [Column("F_VAT")]

    public int VatNumber { get; set; }

}



[Table("dbo.CW_FirmaCommunication")]

public class CW_FirmaCommunication

{

    [Key]

    [Column("FC_VAT")]

    public int VatNumber { get; set; }

    [Column("FC_Data")]

    public string FC_Data { get; set; }

}



protected override void OnModelCreating(DbModelBuilder modelBuilder)

{

    modelBuilder.Entity<CW_FirmaCommunication>()

        .HasRequired(c => c.CwFirma)

        .WithMany()

        .HasForeignKey(f => f.VatNumber);

}

When I run my code, I get the following exception :

Multiplicity is not valid in Role 'CW_FirmaCommunication_CwFirma_Source' in relationship 'CW_FirmaCommunication_CwFirma'. Because the Dependent Role refers to the key properties, the upper bound of the multiplicity of the Dependent Role must be '1'

I have been searching the internet, looking at different solutions here on StackOverflow, but nothing seems to resolve my problem.

Can anyone tell me where I'm going wrong?

1. you use fluent api and mapping annotations - I would prefer to use only one,


2. in annotation mapping you declared that field VatNumber of CW_FirmaCommunication table is primary key (as VatNumber in CW_Firma), which means that you have relation 1:1 while using fluent api you want 1:many.

Basing on your code I made few corrects:

[Table("dbo.CW_FirmaCommunication")]

public class CW_FirmaCommunication

{

    [Key]

    [Column("Communnication_Id")]

    public int CommunicationId { get; set; }



    [Column("FC_VAT")]

    public int VatNumber { get; set; }



    public CW_Firma Firma { get; set; }



    [Column("FC_Data")]        

    public string FC_Data { get; set; }

}

I have added seperate PK for communications table (not FC_VAT), and added navigation property Firma.

New mapping:

modelBuilder.Entity<CW_FirmaCommunication>()

            .HasRequired<CW_Firma>(c => c.Firma)

            .WithMany()

            .HasForeignKey(f => f.VatNumber);

It's working in my test db.

After a lot of searching and trying, this is what I ended up with and what works fine:

public class CW_FirmaCommunication

{

    [Key]

    public int FC_ID { get; set; }

    public int FC_VAT { get; set; }

    public int FC_Type { get; set; }

    public string FC_Data { get; set; }



    [ForeignKey("FC_VAT")]

    public virtual CW_Firma CwFirma { get; set; }

}



public class CW_Firma

{

    [Key]

    public int F_VAT { get; set; }

}

And I removed the code from the "OnModelCreating".