setting a child page

Unary2.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EFUnary
{
    class Program
    {
        static void Main(string[] args)
        {

            using (var ctx = new AppContext())
            {
                var page = new Page()
                {
                    Name = "Child4"
                };

                page.ParentPage = ctx.Pages.FirstOrDefault(x => x.Name == "blah");

                ctx.Pages.Add(page);
                ctx.SaveChanges();

                var child = ctx.Pages.FirstOrDefault(x => x.Name == "Child4");

                Console.WriteLine(child.ParentPage.Name);
                Console.ReadKey();                
            }

        }
    }

    public class AppContext : DbContext
    {
        public AppContext() 
            : base (@"Server=.;Database=UnaryTest;Trusted_Connection=True;")
        {
           
        }

        public DbSet<Page> Pages { get; set; }
    }

    public class Page
    {
        public int PageID { get; set; }

        public string Name { get; set; }

        public Page ParentPage { get; set; }

        [InverseProperty("ParentPage")]
        public virtual ICollection<Page> SubPages { get; set; }
    }
}