using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Mapping.Attributes;
using NHibernate.Dialect;
using NHibernate.Tool.hbm2ddl;
using System.Data;
using System.Data.SqlServerCe;

namespace NHibernateTreeTest
{
   [Class]
   public class Folder
   {
      public Folder()
      {
         this.SubFolders = new List<Folder>();
      }

      public Folder(string name)
      {
         this.Name = name;
         this.SubFolders = new List<Folder>();
      }

      [Id(0, Name = "Id"), Generator(1, Class = "identity")]
      public virtual int Id { get; set; }

      [Property]
      public virtual string Name { get; set; }

      [List(0)]
      [Key(1, Column = "ParentId")]
      [Index(2, Column = "ListIndex")]
      [OneToMany(3, ClassType = typeof(Folder))]
      public virtual IList<Folder> SubFolders { get; set; }
   }

   class Program
   {
      static void Main(string[] args)
      {
         Configuration cfg = createConfiguration();
         if (true)
            initializeDB(cfg);

         Console.Out.WriteLine("\nFolder structure:");

         ISessionFactory sessionFactory = cfg.BuildSessionFactory();
         ISession currentSession = sessionFactory.OpenSession();

         // makes it faster?! => no ;-)
         List<Folder> list = (List<Folder>)currentSession.CreateQuery("from Folder").List<Folder>();

         Folder root = (Folder)currentSession.Get(typeof(Folder), 1);
         if(root != null)
            writeFolder(root, 0);

         currentSession.Close();
         Console.ReadLine();
      }

      private static Configuration createConfiguration()
      {
         Configuration cfg = new Configuration();
         cfg.Configure();

         System.IO.MemoryStream ioStream = new System.IO.MemoryStream();
         HbmSerializer.Default.Serialize(ioStream, System.Reflection.Assembly.GetExecutingAssembly());

         ioStream.Position = 0;
         Console.Out.WriteLine(Encoding.ASCII.GetString(ioStream.GetBuffer()));
         cfg.AddInputStream(ioStream);
         ioStream.Close();

         return cfg;
      }

      private static void initializeDB(Configuration cfg)
      {
         SqlCeEngine engine = new SqlCeEngine("Data Source='DB.sdf';");
         if(System.IO.File.Exists("DB.sdf"))
            System.IO.File.Delete("DB.sdf");
         engine.CreateDatabase();

         ISessionFactory sessionFactory = cfg.BuildSessionFactory();
         ISession currentSession = sessionFactory.OpenSession();
         
         new SchemaExport(cfg).Execute(true, true, false, false);

         ITransaction transaction = currentSession.BeginTransaction();
         Folder root = new Folder("root");
         currentSession.Save(root);
         addRandomFolderTree(currentSession, root, 15);
         transaction.Commit();
      }

      private static Folder addRandomFolderTree(ISession currentSession, Folder folder, int level)
      {
         int childs = new Random().Next(level);
         for (int i = 0; i < childs; i++)
         {
            Folder newFolder = new Folder("folder " + level + "-" + i);
            currentSession.Save(newFolder);
            folder.SubFolders.Add(addRandomFolderTree(currentSession, newFolder, level - 1));
         }
         currentSession.SaveOrUpdate(folder);
         return folder;
      }

      private static void writeFolder(Folder folder, int level)
      {
         for (int i = 0; i < level; i++)
            Console.Out.Write("  ");
         Console.Out.WriteLine(folder.Name);
         for (int i = 0; i < folder.SubFolders.Count; i++)
            writeFolder(folder.SubFolders[i], level + 1);
      }
   }
}

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
   <configSections>
      <section
        name="hibernate-configuration"
        type="NHibernate.Cfg.ConfigurationSectionHandler, NHibernate"
        />
   </configSections>
   <connectionStrings>
      <add name="NHibernateTest2.Properties.Settings.Database1ConnectionString"
        connectionString="Data Source=|DataDirectory|\Database1.sdf"
        providerName="Microsoft.SqlServerCe.Client.3.5" />
   </connectionStrings>
   <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
      <session-factory>
         <property name="show_sql">true</property>
         <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
         
         <property name="dialect">NHibernate.Dialect.MsSqlCeDialect</property>
         <property name="connection.driver_class">NHibernate.Driver.SqlServerCeDriver</property>
         <property name="connection.connection_string">Data Source=DB.sdf</property>
         
         <property name="hibernate.max_fetch_depth">3</property>
         <mapping assembly="NHibernateTreeTest" />
      </session-factory>
   </hibernate-configuration>
</configuration>