System.Data.SQLite

  public sealed partial class SQLiteFactory : IServiceProvider
  {
    private static Type _dbProviderServicesType;
    private static object _sqliteServices;

    static SQLiteFactory()
    {
#if (SQLITE_STANDARD || USE_INTEROP_DLL || PLATFORM_COMPACTFRAMEWORK) && PRELOAD_NATIVE_LIBRARY
        UnsafeNativeMethods.Initialize();
#endif

#if !PLATFORM_COMPACTFRAMEWORK
        SQLiteLog.Initialize();
#endif

        string version =
#if NET_20
            "3.5.0.0";

    /// <summary>
    /// Initializes the connection with the specified connection string
    /// </summary>
    /// <param name="connectionString">The connection string to use on the connection</param>
    public SQLiteConnection(string connectionString)
    {
#if (SQLITE_STANDARD || USE_INTEROP_DLL || PLATFORM_COMPACTFRAMEWORK) && PRELOAD_NATIVE_LIBRARY
      UnsafeNativeMethods.Initialize();
#endif

#if !PLATFORM_COMPACTFRAMEWORK
      SQLiteLog.Initialize();
#endif

      _flags = SQLiteConnectionFlags.Default;
      _connectionState = ConnectionState.Closed;
      _connectionString = "";

      /// <summary>
      /// The name of the environment variable containing the processor
      /// architecture of the current process.
      /// </summary>
      private static readonly string PROCESSOR_ARCHITECTURE =
          "PROCESSOR_ARCHITECTURE";
#endif

      /////////////////////////////////////////////////////////////////////////

      private static readonly string DllFileExtension = ".dll";

      /////////////////////////////////////////////////////////////////////////
      /// <summary>
      /// Stores the mappings between processor architecture names and platform
      /// names.
      /// </summary>
      private static Dictionary<string, string> processorArchitecturePlatforms;

      /// The native module handle for the native SQLite library or the value
      /// IntPtr.Zero.
      /// </summary>
      private static IntPtr _SQLiteModule = IntPtr.Zero;

      /////////////////////////////////////////////////////////////////////////
      /// <summary>
      /// For now, this method simply calls the Initialize method.

      /// </summary>
      static UnsafeNativeMethods()
      {
          Initialize();
      }

      /////////////////////////////////////////////////////////////////////////
      /// <summary>
      /// Attempts to initialize this class by pre-loading the native SQLite
      /// library for the processor architecture of the current process.
      /// </summary>
      internal static void Initialize()
      {
#if !PLATFORM_COMPACTFRAMEWORK
          //
          // NOTE: If the "NoPreLoadSQLite" environment variable is set, skip
          //       all our special code and simply return.
          //
          if (Environment.GetEnvironmentVariable("No_PreLoadSQLite") != null)
              return;
#endif

          //
          // TODO: Make sure this list is updated if the supported processor
          //       architecture names and/or platform names changes.
          //
          if (processorArchitecturePlatforms == null)
          {
              processorArchitecturePlatforms =

          {
              // do nothing.
          }

          return null;
#endif
      }

      /////////////////////////////////////////////////////////////////////////
      /// <summary>
      /// Determines if the dynamic link library file name requires a suffix
      /// and adds it if necessary.
      /// </summary>
      /// <param name="fileName">
      /// The original dynamic link library file name to inspect.
      /// </param>
      /// <returns>
      /// The dynamic link library file name, possibly modified to include an
      /// extension.
      /// </returns>
      private static string FixUpDllFileName(
          string fileName
          )
      {
          if (!String.IsNullOrEmpty(fileName))
          {
              PlatformID platformId = Environment.OSVersion.Platform;

              if ((platformId == PlatformID.Win32S) ||
                  (platformId == PlatformID.Win32Windows) ||
                  (platformId == PlatformID.Win32NT) ||
                  (platformId == PlatformID.WinCE))
              {
                  if (!fileName.EndsWith(DllFileExtension,
                        StringComparison.InvariantCultureIgnoreCase))
                  {
                      return fileName + DllFileExtension;
                  }
              }
          }

          return fileName;
      }

      /////////////////////////////////////////////////////////////////////////
      /// <summary>
      /// Queries and returns the processor architecture of the current
      /// process.
      /// </summary>
      /// <returns>

          if (directory == null)
              return IntPtr.Zero;

          //
          // NOTE: If the native SQLite library exists in the base directory
          //       itself, stop now.
          //
          string fileName = FixUpDllFileName(Path.Combine(directory,
              SQLITE_DLL));

          if (File.Exists(fileName))
              return IntPtr.Zero;

          //
          // NOTE: If the specified processor architecture is null, use the
          //       default.

          if (processorArchitecture == null)
              return IntPtr.Zero;

          //
          // NOTE: Build the full path and file name for the native SQLite
          //       library using the processor architecture name.
          //
          fileName = FixUpDllFileName(Path.Combine(Path.Combine(directory,
              processorArchitecture), SQLITE_DLL));

          //
          // NOTE: If the file name based on the processor architecture name
          // is not found, try using the associated platform name.
          //
          if (!File.Exists(fileName))
          {

              if (platformName == null)
                  return IntPtr.Zero;

              //
              // NOTE: Build the full path and file name for the native SQLite
              //       library using the platform name.
              //
              fileName = FixUpDllFileName(Path.Combine(Path.Combine(directory,
                  platformName), SQLITE_DLL));

              //
              // NOTE: If the file does not exist, skip trying to load it.
              //
              if (!File.Exists(fileName))
                  return IntPtr.Zero;
          }