EF Navigation

 public class Page
    {
        public int Id { get; set; }
        public string MyProperty { get; set; }
        public string MyProperty2 { get; set; }

        public int? CommentId { get; set; }
        [ForeignKey("CommentId")]
        public virtual Comment Comments { get; set; }
    }

    public class Post
    {
        public int Id { get; set; }
        public string MyProperty { get; set; }
        public string MyProperty2 { get; set; }

        public int? CommentId { get; set; }
        [ForeignKey("CommentId")]
        public virtual Comment Comments { get; set; }
    }

    public class Comment
    {
        public int Id { get; set; }
        public string MyProperty { get; set; }
        public string MyProperty2 { get; set; }
        public virtual Page Page { get; set; }
        public virtual Post Post { get; set; }
    }