Entity Framework - Code first - One to Many relationship with shared primary key

Question

Anyone know how to implement this scenario with EF Code First Fluent API:

public class Referancial
{
    // Identity
    public int KeyID { get; set; }

    public string Code { get; set; }

    public virtual ICollection<Translation> Translations { get; set; }

}

public class Translation
{
    // refer to Referancial.KeyID
    public int KeyID { get; set; }

    public int LanguageID { get; set; }

    public string Label { get; set; }

}

thank you for your response

what about data annotations? or you want just the fluent api approach? — Abdul Ahmad, Nov 06 '14 at 16:36
so I shouldn't bother giving an answer that uses data annotations? — Abdul Ahmad, Nov 06 '14 at 16:39

score 1 · Accepted Answer · answered Nov 06 '14 at 18:34

Try with another model, I think that It will suit better for you

public class Referancial
{
    // Identity
    public int KeyID { get; set; }

    public string Code { get; set; }

    public virtual ICollection<Translation> Translations { get; set; }

}

public class Translation
{
    //Translation needs its own Key
    public int ID { get; set; }
    // reference directly the Referencial object instead of the ID
    public Referencial Referencial { get; set; }

    public int LanguageID { get; set; }

    public string Label { get; set; } 
}

To Configure your model

_modelBuilder.Entity<Referancial>().HasKey(r => r.KeyID);
_modelBuilder.Entity<Translation>().HasKey(t => t.ID);
_modelBuilder.Entity<Referancial>().HasMany(r => r.Translations).WithRequired(t => t.Referencial).WillCascadeOnDelete(true);

Saadi Makrem · Answer 2 · 2014-11-06T16:55:22.627

//On model creating :

protected override void OnModelCreating(DbModelBuilder modelBuilder) {

        // Person

        modelBuilder.Entity<Person>().HasKey(e => e.PersonID)
                                     .ToTable("Persons")
                                     .Property(e => e.PersonID)
                                     .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);


        //Referancial
        modelBuilder.Entity<Referancial>().HasKey(e => e.KeyID)
                                          .ToTable("Referancials")
                                          .Property(e => e.KeyID)
                                          .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);


        //Translation
        modelBuilder.Entity<Translation>().ToTable("Translations")
                                          .HasKey(e => e.KeyID)
                                          .Property(e => e.KeyID)
                                          .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);


        modelBuilder.Entity<Referancial>()
                    .HasOptional(e=>e.Translations)
                    .WithMany()
                    .HasForeignKey(e => e.KeyID);

        base.OnModelCreating(modelBuilder);
    }

but it shoz me an error :

One or more validation errors were detected during model generation:

PersonSearch.Models.Referancial_Translations: : Multiplicity conflicts with the referential constraint in Role 'Referancial_Translations_Target' in relationship 'Referancial_Translations'. Because all of the properties in the Dependent Role are non-nullable, multiplicity of the Principal Role must be '1'. Referancial_Translations_Source: : Multiplicity is not valid in Role 'Referancial_Translations_Source' in relationship 'Referancial_Translations'. Because the Dependent Role refers to the key properties, the upper bound of the multiplicity of the Dependent Role must be '1'.

KeyID of the translation can't be at the same time the foreign key and the primary key as in your model. Translation needs its own primary key. — Marc Cals, Nov 06 '14 at 18:37

Entity Framework - Code first - One to Many relationship with shared primary key

2 Answers2