Many to Many relationship EF with foreign keys

Question

I want to configure many to many relationship between 2 entities but I would also like to expose their foreign keys. I found only one concrete solution online like following:

modelBuilder.Entity<E1>()
                            .HasMany(t => t.E1s)
                            .WithMany(t => t.E2s)
                            .Map(m =>
                            {
                                m.ToTable("E1E2");
                                m.MapLeftKey("FKE1");
                                m.MapRightKey("FKE2");
                            });

But map left and right key does not take a properties from my models so I do not have access to them and they will not be filled when I query. So, I do not have access to my foreign key properties.

Hope I was able to explain my problem. Can anyone suggest any other option?

Leonel Sanches da Silva · Accepted Answer · 2014-02-17T21:04:37.567

1

You can create an associative model that has keys from the two entities:

public class AssociativeEntity
{
    [Key]
    public Guid AssociativeEntityId { get; set; }
    public Guid Entity1Id { get; set; }
    public Guid Entity2Id { get; set; }

    [Display(Name = "Entity1", ResourceType = typeof(Resources.Language))]
    public virtual Entity1 Entity1 { get; set; }
    [Display(Name = "Entity2", ResourceType = typeof(Resources.Language))]
    public virtual Entity2 Entity2 { get; set; }
}

Entity 1:

public class Entity1
{
    [Key]
    public Guid Entity1Id { get; set; }

    /* Describe the other properties here */

    [Display(Name = "AssociativeEntities", ResourceType = typeof(Resources.Language))]
    public virtual ICollection<AssociativeEntity> AssociativeEntities { get; set; }
}

Entity 2:

public class Entity2
{
    [Key]
    public Guid Entity2Id { get; set; }

    /* Describe the other properties here */

    [Display(Name = "AssociativeEntities", ResourceType = typeof(Resources.Language))]
    public virtual ICollection<AssociativeEntity> AssociativeEntities { get; set; }
}

edited Feb 17 '14 at 21:04

answered Feb 17 '14 at 05:11

Leonel Sanches da Silva

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Thanks for your answer. By 'associative model' do you mean I will specify the model for the intermediate or join table that EF creates itself? – lbrahim Feb 17 '14 at 05:15
1

Yes. The problem with the modelBuilder is the limited set of options that you have to work with the associative model. For this reason, I recommend you to created the model manually. – Leonel Sanches da Silva Feb 17 '14 at 05:22
I cannot configure the join table properly. Could you please help me with that? Do I remove the `List<>` property from both the join entities? – lbrahim Feb 17 '14 at 07:38
@Md.lbrahim Asnwer improved as requested. – Leonel Sanches da Silva Feb 17 '14 at 21:04

Many to Many relationship EF with foreign keys

1 Answers1