Question

I have a working model, but have noticed that the relationship has been created twice in the database. Originally, it created two columns in the table, but with the addition of a specified foreign key attribute it has now just the one.

I have an Account class, which has many employers who can use the account. (one to many) Here are the classes:

public class Account
{
    public int AccountId { get; set; }

    [Required(ErrorMessage = Constants.ValidationMessages.FieldRequired)]
    public string  Name { get; set; }

    public int? PrimaryUserId { get; set; }
    [ForeignKey("PrimaryUserId")]
    public Employer PrimaryUser { get; set; }

    [ForeignKey("EmpAccountId")]
    public ICollection<Employer> Employers { get; set; }

}

here is the inherited Employer class

public class Employer : User
{
    public Employer()
    {
        DepartmentsToPost = new Collection<Department>();
        Contacts = new Collection<Contact>();
    }

    [Display(Name = "Workplaces to advertise jobs")]
    public virtual ICollection<Department> DepartmentsToPost { get; set; }

    public int EmpAccountId { get; set; }
    [ForeignKey("EmpAccountId")]
    public virtual Account Account { get; set; }

    public override string UserType
    {
        get { return "Employer"; }
    }
}

User Table:

UserId
Username
FirstName     
Surname 
EmpAccountId
Discriminator 

Account Table

AccountId
Name
PrimaryUserId

There is one link back to the User table – this is for the PrimaryUser field, and this is correct. There are two other relationships: Account -> Employers. EF has named them Account_Employers and Employer_Account. These are duplicates.

How can I prevent this occuring?

Answer 1

The Employers collection should be decorated with InversePropertyAttribute to point to the navigational property on the other side.

public class Account
{
    public int AccountId { get; set; }

    [Required(ErrorMessage = Constants.ValidationMessages.FieldRequired)]
    public string  Name { get; set; }

    public int? PrimaryUserId { get; set; }
    [ForeignKey("PrimaryUserId")]
    public Employer PrimaryUser { get; set; }

    [InverseProperty("Account")]
    public ICollection<Employer> Employers { get; set; }    
}