Double foreign key generation

问题

This is a followup-question of this question, where i had a similar problem. But this is solved now by default foreign key convention.

My problem now is (in short), that my migrations generates

int ReferencedEntityID; int ReferencedEntity_ReferencedEntityID;

where one is an integer property in my model and the other one is a virtual property.

My migrations generates this:

"dbo.Contracts",
            c => new
                {
                    ContractId = c.Int(nullable: false, identity: true),
                    PricePerUnit = c.Double(nullable: false),
                    Unit = c.Int(nullable: false),
                    Currency = c.Int(nullable: false),
                    ClientId = c.Int(nullable: false),
                    CompanyId = c.Int(nullable: false),
                    ArticleId = c.Int(nullable: false),
                    Client_ClientId = c.Int(),
                    Article_ArticleId = c.Int(),
                })

As you can see, Client & Article are referenced twice.

Here are my models

public class Client {
    public Client() { }

    [Key]
    public int ClientId { get; set; }
    public string Number { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string ZipCode { get; set; }
    public string City { get; set; }
    public string AddressLine1 { get; set; }
    public string AddressLine2 { get; set; }
    public string Memo { get; set; }
    public bool isMerchant { get; set; }

    public string Name
    {
        get
        {
            return string.Format("{0} {1}", FirstName, LastName);
        }
    }

    public int? MerchantReferenceId { get; set; }
    public virtual Client MerchantReference { get; set; }
    [Required]
    public int CompanyId { get; set; }
    public virtual Company Company { get; set; }
    public virtual ICollection<Contract> Contracts { get; set; }
    public virtual ICollection<Order> Orders { get; set; }
}

public class Article {

    public Article() { }

    [Key]
    public int ArticleId { get; set; }
    [Required]
    public string Code { get; set; }
    public string Name { get; set; }
    public bool TrackStock { get; set; }
    public int CurrentStock { get; set; }
    public double? Price { get; set; }

    [Required]
    public int CompanyId { get; set; }
    public virtual Company Company { get; set; }
    [Required]
    public int CategoryId { get; set; }
    public virtual Category Category { get; set; }

    public virtual ICollection<Contract> Contracts { get; set; }
    public virtual ICollection<Order> Orders { get; set; }
}

public class Contract {

    public Contract() { }

    [Key]
    public int ContractId { get; set; }
    public double PricePerUnit { get; set; }
    public int Unit { get; set; }
    public int Currency { get; set; }

    [Required]
    public int ClientId { get; set; }
  //  [ForeignKey("ClientId")]
    public virtual Client Client { get; set; }

    [Required]
    public int CompanyId { get; set; }
    //[ForeignKey("CompanyID")]
    public virtual Company Company { get; set; }

    [Required]
    public int ArticleId { get; set; }
   // [ForeignKey("ArticleId")]
    public virtual Article Article { get; set; }

}

Here is my OnModelCreating()

   protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
           // modelBuilder.Entity<Contract>().HasRequired(bm => bm.Company).WithMany().WillCascadeOnDelete(false);
            modelBuilder.Entity<Contract>().HasRequired(bm => bm.Article).WithMany().HasForeignKey(dl => dl.ArticleId).WillCascadeOnDelete(false);//.Map( dl => dl.MapKey("ArticleId"))
            modelBuilder.Entity<Contract>().HasRequired(bm => bm.Client).WithMany().HasForeignKey(dl => dl.ClientId).WillCascadeOnDelete(false);//.Map(dl => dl.MapKey("ClientId"))
            modelBuilder.Entity<Article>().HasRequired(bm => bm.Company).WithMany().HasForeignKey(dl => dl.CompanyId).WillCascadeOnDelete(false);//.Map(dl => dl.MapKey("CompanyId"))
            modelBuilder.Entity<Measurement>().HasRequired(bm => bm.Company).WithMany().HasForeignKey(dl => dl.CompanyId).WillCascadeOnDelete(false); //.Map(dl => dl.MapKey("CompanyId"))
            modelBuilder.Entity<Order>().HasRequired(bm => bm.Client).WithMany().HasForeignKey(dl => dl.ClientId).WillCascadeOnDelete(false); //.Map(dl => dl.MapKey("ClientId"))
            modelBuilder.Entity<Order>().HasRequired(bm => bm.Article).WithMany().HasForeignKey(dl => dl.ArticleId).WillCascadeOnDelete(false);//.Map(dl => dl.MapKey("ArticleId"))
            modelBuilder.Entity<IncomingMeasurement>().HasRequired(bm => bm.client).WithMany().HasForeignKey(dl => dl.ClientId).WillCascadeOnDelete(false);//.Map(dl => dl.MapKey("ClientId"))
            modelBuilder.Entity<Client>().HasOptional(c => c.MerchantReference).WithMany().HasForeignKey(dl => dl.MerchantReferenceId); //.Map(dl => dl.MapKey("MerchantReferenceId"))

            //Required fields


            base.OnModelCreating(modelBuilder);
        }

What do i have to do, to create them both:

• Required
• Both in one property in my db-schema (as it should)

回答1:

It is OK, even recommended, to have primitive FK properties (like ArticleId) accompanying the "real" references. In EF this is called a foreign key association as opposed to an independent association where there is only a reference (like Article.Company).

So you can keep your model the way it is. You just have to specify the foreign keys.

I tried with a few classes in the model of your previous question and this produced the desired results:

modelBuilder.Entity<Article>().HasMany(a => a.Contracts)
    .WithRequired(c => c.Article)
    .HasForeignKey(c => c.ArticleID).WillCascadeOnDelete(false);
modelBuilder.Entity<Client>().HasMany(c => c.Contracts)
    .WithRequired(c => c.Client)
    .HasForeignKey(c => c.ClientID).WillCascadeOnDelete(false);
modelBuilder.Entity<Company>().HasMany(c => c.Articles)
    .WithRequired(a => a.Company)
    .HasForeignKey(c => c.CompanyID).WillCascadeOnDelete(false);

Note that I turned around the definitions because when I did it your way, but with HasForeignKey it still duplicated the FK fields. I'm not sure why.

来源：https://stackoverflow.com/questions/14490025/double-foreign-key-generation