sqlitecommand.cs

sqlite 3.3.8 支持加密的版本

        {
          throw new NotSupportedException();
        }
      }
    }

    /// <summary>
    /// Forwards to the local CreateParameter() function
    /// </summary>
    /// <returns></returns>
    protected override DbParameter CreateDbParameter()
    {
      return CreateParameter();
    }

    /// <summary>
    /// Create a new parameter
    /// </summary>
    /// <returns></returns>
    public new SQLiteParameter CreateParameter()
    {
      return new SQLiteParameter();
    }

    /// <summary>
    /// The connection associated with this command
    /// </summary>
#if !PLATFORM_COMPACTFRAMEWORK
    [DefaultValue((string)null), Editor("Microsoft.VSDesigner.Data.Design.DbConnectionEditor, Microsoft.VSDesigner, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", "System.Drawing.Design.UITypeEditor, System.Drawing, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
#endif
    public new SQLiteConnection Connection
    {
      get { return _cnn; }
      set
      {
        if (_activeReader != null)
          throw new InvalidOperationException("Cannot set Connection while a DataReader is active");

        if (_cnn != null)
        {
          ClearCommands();
          _cnn._commandList.Remove(this);
        }

        _cnn = value;

        if (_cnn != null)
          _cnn._commandList.Add(this);
      }
    }

    /// <summary>
    /// Forwards to the local Connection property
    /// </summary>
    protected override DbConnection DbConnection
    {
      get
      {
        return Connection;
      }
      set
      {
        Connection = (SQLiteConnection)value;
      }
    }

    /// <summary>
    /// Returns the SQLiteParameterCollection for the given command
    /// </summary>
#if !PLATFORM_COMPACTFRAMEWORK
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
#endif
    public new SQLiteParameterCollection Parameters
    {
      get { return _parameterCollection; }
    }

    /// <summary>
    /// Forwards to the local Parameters property
    /// </summary>
    protected override DbParameterCollection DbParameterCollection
    {
      get
      {
        return Parameters;
      }
    }

    /// <summary>
    /// The transaction associated with this command.  SQLite only supports one transaction per connection, so this property forwards to the
    /// command's underlying connection.
    /// </summary>
#if !PLATFORM_COMPACTFRAMEWORK
    [Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
#endif
    public new SQLiteTransaction Transaction
    {
      get { return _transaction; }
      set
      {
        if (_cnn != null)
        {
          if (_activeReader != null)
            throw new InvalidOperationException("Cannot set Transaction while a DataReader is active");

          if (value != null)
          {
            if (value._cnn != _cnn)
              throw new ArgumentException("Transaction is not associated with the command's connection");
          }
          _transaction = value;
        }
        else if (value != null)
          throw new ArgumentOutOfRangeException("SQLiteTransaction", "Not associated with a connection");
      }
    }

    /// <summary>
    /// Forwards to the local Transaction property
    /// </summary>
    protected override DbTransaction DbTransaction
    {
      get
      {
        return Transaction;
      }
      set
      {
        Transaction = (SQLiteTransaction)value;
      }
    }

    /// <summary>
    /// This function ensures there are no active readers, that we have a valid connection,
    /// that the connection is open, that all statements are prepared and all parameters are assigned
    /// in preparation for allocating a data reader.
    /// </summary>
    private void InitializeForReader()
    {
      if (_activeReader != null)
        throw new InvalidOperationException("DataReader already active on this command");

      if (_cnn == null)
        throw new InvalidOperationException("No connection associated with this command");

      if (_cnn.State != ConnectionState.Open)
        throw new InvalidOperationException("Database is not open");

      // Map all parameters for statements already built
      _parameterCollection.MapParameters(null);

      // Set the default command timeout
      _cnn._sql.SetTimeout(_commandTimeout * 1000);
    }

    /// <summary>
    /// Creates a new SQLiteDataReader to execute/iterate the array of SQLite prepared statements
    /// </summary>
    /// <param name="behavior">The behavior the data reader should adopt</param>
    /// <returns>Returns a SQLiteDataReader object</returns>
    protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
    {
      return ExecuteReader(behavior);
    }

    /// <summary>
    /// Overrides the default behavior to return a SQLiteDataReader specialization class
    /// </summary>
    /// <param name="behavior">The flags to be associated with the reader</param>
    /// <returns>A SQLiteDataReader</returns>
    public new SQLiteDataReader ExecuteReader(CommandBehavior behavior)
    {
      InitializeForReader();

      SQLiteDataReader rd = new SQLiteDataReader(this, behavior);
      _activeReader = rd;

      return rd;
    }

    /// <summary>
    /// Overrides the default behavior of DbDataReader to return a specialized SQLiteDataReader class
    /// </summary>
    /// <returns>A SQLiteDataReader</returns>
    public new SQLiteDataReader ExecuteReader()
    {
      return ExecuteReader(CommandBehavior.Default);
    }

    /// <summary>
    /// Called by the SQLiteDataReader when the data reader is closed.
    /// </summary>
    internal void ClearDataReader()
    {
      _activeReader = null;
    }

    /// <summary>
    /// Execute the command and return the number of rows inserted/updated affected by it.
    /// </summary>
    /// <returns></returns>
    public override int ExecuteNonQuery()
    {
      InitializeForReader();

      int nAffected = 0;
      int x = 0;
      SQLiteStatement stmt;

      for(;;)
      {
        stmt = GetStatement(x);
        x++;
        if (stmt == null) break;

        _cnn._sql.Step(stmt);
        nAffected += _cnn._sql.Changes;
        _cnn._sql.Reset(stmt);
      }

      return nAffected;
    }

    /// <summary>
    /// Execute the command and return the first column of the first row of the resultset
    /// (if present), or null if no resultset was returned.
    /// </summary>
    /// <returns>The first column of the first row of the first resultset from the query</returns>
    public override object ExecuteScalar()
    {
      InitializeForReader();

      int x = 0;
      object ret = null;
      SQLiteType typ = new SQLiteType();
      SQLiteStatement stmt;

      // We step through every statement in the command, but only grab the first row of the first resultset.
      // We keep going even after obtaining it.
      for (;;)
      {
        stmt = GetStatement(x);
        x++;
        if (stmt == null) break;

        if (_cnn._sql.Step(stmt) == true && ret == null)
        {
          ret = _cnn._sql.GetValue(stmt, 0, ref typ);
        }
        _cnn._sql.Reset(stmt);
      }

      return ret;
    }

    /// <summary>
    /// Does nothing.  Commands are prepared as they are executed the first time, and kept in prepared state afterwards.
    /// </summary>
    public override void Prepare()
    {
    }

    /// <summary>
    /// Sets the method the SQLiteCommandBuilder uses to determine how to update inserted or updated rows in a DataTable.
    /// </summary>
    [DefaultValue(UpdateRowSource.FirstReturnedRecord)]
    public override UpdateRowSource UpdatedRowSource
    {
      get
      {
        return _updateRowSource;
      }
      set
      {
        _updateRowSource = value;
      }
    }

    /// <summary>
    /// Determines if the command is visible at design time.  Defaults to True.
    /// </summary>
#if !PLATFORM_COMPACTFRAMEWORK
    [DesignOnly(true), Browsable(false), DefaultValue(true), EditorBrowsable(EditorBrowsableState.Never)]
#endif
    public override bool DesignTimeVisible
    {
      get
      {
        return _designTimeVisible;
      }
      set
      {
        _designTimeVisible = value;
#if !PLATFORM_COMPACTFRAMEWORK
        TypeDescriptor.Refresh(this);
#endif
      }
    }

    /// <summary>
    /// Clones a command, including all its parameters
    /// </summary>
    /// <returns>A new SQLiteCommand with the same commandtext, connection and parameters</returns>
    public object Clone()
    {
      return new SQLiteCommand(this);
    }
  }
}