Optional One-to-many Relationship in Entity Framework

Question

I\'m having issues getting an optional one-to-many relationship to work.

My model is:

public class Person
{
    public int Identifier { get; set; }
          


        

Answer 1

You can try this:

this.HasOptional(s => s.Department)
    .WithMany(s => s.Members)
    .HasForeignKey(s => s.MemberOfDepartment);

Answer 2

modelBuilder.Entity<Department>().HasMany(x => x.MemberOfDepartment).WithOptional();

Answer 3

Also try this:

public class Person
{
    public int Identifier { get; set; }
    public int DepartmentIdentifier {get; set;}
    public virtual Department Department { get; set; }
}

public class Department
{
    public int Identifier { get; set; }

    public virtual IList<Person> Members { get; set; }
}

EF Person config using Fluent API:

this.HasRequired(p => p.Department).WithMany(d => d.Members).HasForeignKey(p => 
p.DepartmentIdentifier);

this.Property(p => p.DepartmentIdentifier).IsRequired();