EF one-to-one not working

Question

I have a class User:

[Table("User")]
public class User {

    public User() {
        BusinessNumber = new BusinessNumber();
    }

    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int UserId { get; set; }
    public string Username { get; set; }

    [Required]
    public virtual BusinessNumber BusinessNumber { get; set; }

}

And BusinessNumber:

public class BusinessNumber {

    public BusinessNumber() {
        Subscribers = new List<SubscriberNumber>();
    }

    [Key, ForeignKey("User")]
    public int UserId { get; set; }
    public string Sid { get; set; }
    public string PhoneNumber { get; set; }
    public string VenueName { get; set; }
    public virtual User User { get; set; }
    public List<SubscriberNumber> Subscribers { get; set; }

}

public class SubscriberNumber {

    public SubscriberNumber() {}

    [Key]
    public int SubscriberNumberId { get; set; }
    public string PhoneNumber { get; set; }

}

With the following mapping:

public class NumberConfiguration : EntityTypeConfiguration<BusinessNumber> {
    public NumberConfiguration() {
        HasKey(c => c.UserId);
        Property(c => c.UserId).HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);
        HasRequired(c => c.User).WithRequiredDependent(s => s.BusinessNumber);
    }
}

The following code results in a new BusinessNumber, without the Id supplied. If I inspect the database, I see a User with Id 1 and a BusinessNumber with Id 1 , yet user.BusinessNumber.Id is 0.

var user = db.Users.First(s => s.Username == username);

I tried using an Include but get a multiplicity error:

var user = db.Users.Include(s => s.BusinessNumber).First(s => s.Username == username);

What am I doing wrong?

Answer 1

Are you sure this code is correct:

public User() 
{
   BusinessNumber = new BusinessNumber();
}

Because it will create a new BusinessNumber with an ID zero; sounds like the issue you are experiencing. I think the singulars you need to leave null initially.