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  • 企业库 AccessHelper

    using System;
    using System.Data;
    using System.Xml;
    using System.Data.OleDb;
    using System.Collections;

    namespace Anboo.Steel.Utility
    {
        /// <summary>
        /// The AccessHelper class is intended to encapsulate high performance, scalable best practices for
        /// common uses of SqlClient
        /// </summary>
        public sealed class AccessHelper
        {
            #region private utility methods & constructors

            // Since this class provides only static methods, make the default constructor private to prevent
            // instances from being created with "new AccessHelper()"
            private AccessHelper() { }

            /// <summary>
            /// This method is used to attach array of OleDbParameters to a OleDbCommand.
            ///
            /// This method will assign a value of DbNull to any parameter with a direction of
            /// InputOutput and a value of null. 
            ///
            /// This behavior will prevent default values from being used, but
            /// this will be the less common case than an intended pure output parameter (derived as InputOutput)
            /// where the user provided no input value.
            /// </summary>
            /// <param name="command">The command to which the parameters will be added</param>
            /// <param name="commandParameters">An array of OleDbParameters to be added to command</param>
            private static void AttachParameters(OleDbCommand command, OleDbParameter[] commandParameters)
            {
                if (command == null) throw new ArgumentNullException("command");
                if (commandParameters != null)
                {
                    foreach (OleDbParameter p in commandParameters)
                    {
                        if (p != null)
                        {
                            // Check for derived output value with no value assigned
                            if ((p.Direction == ParameterDirection.InputOutput ||
                                p.Direction == ParameterDirection.Input) &&
                                (p.Value == null))
                            {
                                p.Value = DBNull.Value;
                            }
                            command.Parameters.Add(p);
                        }
                    }
                }
            }

            /// <summary>
            /// This method assigns dataRow column values to an array of OleDbParameters
            /// </summary>
            /// <param name="commandParameters">Array of OleDbParameters to be assigned values</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values</param>
            private static void AssignParameterValues(OleDbParameter[] commandParameters, DataRow dataRow)
            {
                if ((commandParameters == null) || (dataRow == null))
                {
                    // Do nothing if we get no data
                    return;
                }

                int i = 0;
                // Set the parameters values
                foreach (OleDbParameter commandParameter in commandParameters)
                {
                    // Check the parameter name
                    if (commandParameter.ParameterName == null ||
                        commandParameter.ParameterName.Length <= 1)
                        throw new Exception(
                            string.Format(
                                "Please provide a valid parameter name on the parameter #{0}, the ParameterName property has the following value: '{1}'.",
                                i, commandParameter.ParameterName));
                    if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1)
                        commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];
                    i++;
                }
            }

            /// <summary>
            /// This method assigns an array of values to an array of OleDbParameters
            /// </summary>
            /// <param name="commandParameters">Array of OleDbParameters to be assigned values</param>
            /// <param name="parameterValues">Array of objects holding the values to be assigned</param>
            private static void AssignParameterValues(OleDbParameter[] commandParameters, object[] parameterValues)
            {
                if ((commandParameters == null) || (parameterValues == null))
                {
                    // Do nothing if we get no data
                    return;
                }

                // We must have the same number of values as we pave parameters to put them in
                if (commandParameters.Length != parameterValues.Length)
                {
                    throw new ArgumentException("Parameter count does not match Parameter Value count.");
                }

                // Iterate through the OleDbParameters, assigning the values from the corresponding position in the
                // value array
                for (int i = 0, j = commandParameters.Length; i < j; i++)
                {
                    // If the current array value derives from IDbDataParameter, then assign its Value property
                    if (parameterValues[i] is IDbDataParameter)
                    {
                        IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i];
                        if (paramInstance.Value == null)
                        {
                            commandParameters[i].Value = DBNull.Value;
                        }
                        else
                        {
                            commandParameters[i].Value = paramInstance.Value;
                        }
                    }
                    else if (parameterValues[i] == null)
                    {
                        commandParameters[i].Value = DBNull.Value;
                    }
                    else
                    {
                        commandParameters[i].Value = parameterValues[i];
                    }
                }
            }

            /// <summary>
            /// This method opens (if necessary) and assigns a connection, transaction, command type and parameters
            /// to the provided command
            /// </summary>
            /// <param name="command">The OleDbCommand to be prepared</param>
            /// <param name="connection">A valid OleDbConnection, on which to execute this command</param>
            /// <param name="transaction">A valid OleDbTransaction, or 'null'</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of OleDbParameters to be associated with the command or 'null' if no parameters are required</param>
            /// <param name="mustCloseConnection"><c>true</c> if the connection was opened by the method, otherwose is false.</param>
            private static void PrepareCommand(OleDbCommand command, OleDbConnection connection, OleDbTransaction transaction, CommandType commandType, string commandText, OleDbParameter[] commandParameters, out bool mustCloseConnection)
            {
                if (command == null) throw new ArgumentNullException("command");
                if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");

                // If the provided connection is not open, we will open it
                if (connection.State != ConnectionState.Open)
                {
                    mustCloseConnection = true;
                    connection.Open();
                }
                else
                {
                    mustCloseConnection = false;
                }

                // Associate the connection with the command
                command.Connection = connection;

                // Set the command text (stored procedure name or SQL statement)
                command.CommandText = commandText;

                // If we were provided a transaction, assign it
                if (transaction != null)
                {
                    if (transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                    command.Transaction = transaction;
                }

                // Set the command type
                command.CommandType = commandType;

                // Attach the command parameters if they are provided
                if (commandParameters != null)
                {
                    AttachParameters(command, commandParameters);
                }
                return;
            }

            #endregion private utility methods & constructors

            #region ExecuteNonQuery

            /// <summary>
            /// Execute a OleDbCommand (that returns no resultset and takes no parameters) against the database specified in
            /// the connection string
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteNonQuery(connectionString, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns no resultset) against the database specified in the connection string
            /// using the provided parameters
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");

                // Create & open a OleDbConnection, and dispose of it after we are done
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();

                    // Call the overload that takes a connection in place of the connection string
                    return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns no resultset) against the database specified in
            /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored prcedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns no resultset and takes no parameters) against the provided OleDbConnection.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(OleDbConnection connection, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteNonQuery(connection, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns no resultset) against the specified OleDbConnection
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connection == null) throw new ArgumentNullException("connection");

                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();
                bool mustCloseConnection = false;
                PrepareCommand(cmd, connection, (OleDbTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);

                // Finally, execute the command
                int retval = cmd.ExecuteNonQuery();

                // Detach the OleDbParameters from the command object, so they can be used again
                cmd.Parameters.Clear();
                if (mustCloseConnection)
                    connection.Close();
                return retval;
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns no resultset) against the specified OleDbConnection
            /// using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(OleDbConnection connection, string spName, params object[] parameterValues)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns no resultset and takes no parameters) against the provided OleDbTransaction.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(OleDbTransaction transaction, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteNonQuery(transaction, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns no resultset) against the specified OleDbTransaction
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");

                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();
                bool mustCloseConnection = false;
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);

                // Finally, execute the command
                int retval = cmd.ExecuteNonQuery();

                // Detach the OleDbParameters from the command object, so they can be used again
                cmd.Parameters.Clear();
                return retval;
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns no resultset) against the specified
            /// OleDbTransaction using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQuery(OleDbTransaction transaction, string spName, params object[] parameterValues)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
                }
            }

            #endregion ExecuteNonQuery

            #region ExecuteDataset

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the database specified in
            /// the connection string.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteDataset(connectionString, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the database specified in the connection string
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");

                // Create & open a OleDbConnection, and dispose of it after we are done
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();

                    // Call the overload that takes a connection in place of the connection string
                    return ExecuteDataset(connection, commandType, commandText, commandParameters);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the database specified in
            /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbConnection.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(OleDbConnection connection, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteDataset(connection, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connection == null) throw new ArgumentNullException("connection");

                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();
                bool mustCloseConnection = false;
                PrepareCommand(cmd, connection, (OleDbTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);

                // Create the DataAdapter & DataSet
                using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    ds.Locale = System.Globalization.CultureInfo.InvariantCulture;
                    // Fill the DataSet using default values for DataTable names, etc
                    da.Fill(ds);

                    // Detach the OleDbParameters from the command object, so they can be used again
                    cmd.Parameters.Clear();

                    if (mustCloseConnection)
                        connection.Close();

                    // Return the dataset
                    return ds;
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(OleDbConnection connection, string spName, params object[] parameterValues)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbTransaction.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(OleDbTransaction transaction, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteDataset(transaction, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the specified OleDbTransaction
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");

                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();
                bool mustCloseConnection = false;
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);

                // Create the DataAdapter & DataSet
                using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    ds.Locale = System.Globalization.CultureInfo.InvariantCulture;
                    // Fill the DataSet using default values for DataTable names, etc
                    da.Fill(ds);

                    // Detach the OleDbParameters from the command object, so they can be used again
                    cmd.Parameters.Clear();

                    // Return the dataset
                    return ds;
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified
            /// OleDbTransaction using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDataset(OleDbTransaction transaction, string spName, params object[] parameterValues)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
                }
            }

            #endregion ExecuteDataset

            #region ExecuteReader

            /// <summary>
            /// This enum is used to indicate whether the connection was provided by the caller, or created by AccessHelper, so that
            /// we can set the appropriate CommandBehavior when calling ExecuteReader()
            /// </summary>
            private enum OleDbConnectionOwnership
            {
                /// <summary>Connection is owned and managed by AccessHelper</summary>
                Internal,
                /// <summary>Connection is owned and managed by the caller</summary>
                External
            }

            /// <summary>
            /// Create and prepare a OleDbCommand, and call ExecuteReader with the appropriate CommandBehavior.
            /// </summary>
            /// <remarks>
            /// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
            ///
            /// If the caller provided the connection, we want to leave it to them to manage.
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection, on which to execute this command</param>
            /// <param name="transaction">A valid OleDbTransaction, or 'null'</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of OleDbParameters to be associated with the command or 'null' if no parameters are required</param>
            /// <param name="connectionOwnership">Indicates whether the connection parameter was provided by the caller, or created by AccessHelper</param>
            /// <returns>OleDbDataReader containing the results of the command</returns>
            private static OleDbDataReader ExecuteReader(OleDbConnection connection, OleDbTransaction transaction, CommandType commandType, string commandText, OleDbParameter[] commandParameters, OleDbConnectionOwnership connectionOwnership)
            {
                if (connection == null) throw new ArgumentNullException("connection");

                bool mustCloseConnection = false;
                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();
                try
                {
                    PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);

                    // Create a reader
                    OleDbDataReader dataReader;

                    // Call ExecuteReader with the appropriate CommandBehavior
                    if (connectionOwnership == OleDbConnectionOwnership.External)
                    {
                        dataReader = cmd.ExecuteReader();
                    }
                    else
                    {
                        dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                    }

                    // Detach the OleDbParameters from the command object, so they can be used again.
                    // HACK: There is a problem here, the output parameter values are fletched
                    // when the reader is closed, so if the parameters are detached from the command
                    // then the SqlReader can磘 set its values.
                    // When this happen, the parameters can磘 be used again in other command.
                    bool canClear = true;
                    foreach (OleDbParameter commandParameter in cmd.Parameters)
                    {
                        if (commandParameter.Direction != ParameterDirection.Input)
                            canClear = false;
                    }

                    if (canClear)
                    {
                        cmd.Parameters.Clear();
                    }

                    return dataReader;
                }
                catch
                {
                    if (mustCloseConnection)
                        connection.Close();
                    throw;
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the database specified in
            /// the connection string.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteReader(connectionString, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the database specified in the connection string
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                OleDbConnection connection = null;
                try
                {
                    connection = new OleDbConnection(connectionString);
                    connection.Open();

                    // Call the private overload that takes an internally owned connection in place of the connection string
                    return ExecuteReader(connection, null, commandType, commandText, commandParameters, OleDbConnectionOwnership.Internal);
                }
                catch
                {
                    // If we fail to return the SqlDatReader, we need to close the connection ourselves
                    if (connection != null) connection.Close();
                    throw;
                }

            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the database specified in
            /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    AssignParameterValues(commandParameters, parameterValues);

                    return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbConnection.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteReader(connection, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                // Pass through the call to the private overload using a null transaction value and an externally owned connection
                return ExecuteReader(connection, (OleDbTransaction)null, commandType, commandText, commandParameters, OleDbConnectionOwnership.External);
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(OleDbConnection connection, string spName, params object[] parameterValues)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    AssignParameterValues(commandParameters, parameterValues);

                    return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteReader(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbTransaction.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(OleDbTransaction transaction, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteReader(transaction, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the specified OleDbTransaction
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///   OleDbDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");

                // Pass through to private overload, indicating that the connection is owned by the caller
                return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, OleDbConnectionOwnership.External);
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified
            /// OleDbTransaction using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  OleDbDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReader(OleDbTransaction transaction, string spName, params object[] parameterValues)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    AssignParameterValues(commandParameters, parameterValues);

                    return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
                }
            }

            #endregion ExecuteReader

            #region ExecuteScalar

            /// <summary>
            /// Execute a OleDbCommand (that returns a 1x1 resultset and takes no parameters) against the database specified in
            /// the connection string.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteScalar(connectionString, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a 1x1 resultset) against the database specified in the connection string
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                // Create & open a OleDbConnection, and dispose of it after we are done
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();

                    // Call the overload that takes a connection in place of the connection string
                    return ExecuteScalar(connection, commandType, commandText, commandParameters);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a 1x1 resultset) against the database specified in
            /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a 1x1 resultset and takes no parameters) against the provided OleDbConnection.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(OleDbConnection connection, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteScalar(connection, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a 1x1 resultset) against the specified OleDbConnection
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connection == null) throw new ArgumentNullException("connection");

                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();

                bool mustCloseConnection = false;
                PrepareCommand(cmd, connection, (OleDbTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);

                // Execute the command & return the results
                object retval = cmd.ExecuteScalar();

                // Detach the OleDbParameters from the command object, so they can be used again
                cmd.Parameters.Clear();

                if (mustCloseConnection)
                    connection.Close();

                return retval;
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a 1x1 resultset) against the specified OleDbConnection
            /// using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(OleDbConnection connection, string spName, params object[] parameterValues)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a 1x1 resultset and takes no parameters) against the provided OleDbTransaction.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(OleDbTransaction transaction, CommandType commandType, string commandText)
            {
                // Pass through the call providing null for the set of OleDbParameters
                return ExecuteScalar(transaction, commandType, commandText, (OleDbParameter[])null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a 1x1 resultset) against the specified OleDbTransaction
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");

                // Create a command and prepare it for execution
                OleDbCommand cmd = new OleDbCommand();
                bool mustCloseConnection = false;
                PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);

                // Execute the command & return the results
                object retval = cmd.ExecuteScalar();

                // Detach the OleDbParameters from the command object, so they can be used again
                cmd.Parameters.Clear();
                return retval;
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a 1x1 resultset) against the specified
            /// OleDbTransaction using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalar(OleDbTransaction transaction, string spName, params object[] parameterValues)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // PPull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
                }
            }

            #endregion ExecuteScalar

            #region FillDataset
            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the database specified in
            /// the connection string.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)</param>
            public static void FillDataset(string connectionString, CommandType commandType, string commandText, DataSet dataSet, string[] tableNames)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (dataSet == null) throw new ArgumentNullException("dataSet");

                // Create & open a OleDbConnection, and dispose of it after we are done
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();

                    // Call the overload that takes a connection in place of the connection string
                    FillDataset(connection, commandType, commandText, dataSet, tableNames);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the database specified in the connection string
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            public static void FillDataset(string connectionString, CommandType commandType,
                string commandText, DataSet dataSet, string[] tableNames,
                params OleDbParameter[] commandParameters)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (dataSet == null) throw new ArgumentNullException("dataSet");
                // Create & open a OleDbConnection, and dispose of it after we are done
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();

                    // Call the overload that takes a connection in place of the connection string
                    FillDataset(connection, commandType, commandText, dataSet, tableNames, commandParameters);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the database specified in
            /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, 24);
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>   
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            public static void FillDataset(string connectionString, string spName,
                DataSet dataSet, string[] tableNames,
                params object[] parameterValues)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (dataSet == null) throw new ArgumentNullException("dataSet");
                // Create & open a OleDbConnection, and dispose of it after we are done
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    connection.Open();

                    // Call the overload that takes a connection in place of the connection string
                    FillDataset(connection, spName, dataSet, tableNames, parameterValues);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbConnection.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>   
            public static void FillDataset(OleDbConnection connection, CommandType commandType,
                string commandText, DataSet dataSet, string[] tableNames)
            {
                FillDataset(connection, commandType, commandText, dataSet, tableNames, null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            public static void FillDataset(OleDbConnection connection, CommandType commandType,
                string commandText, DataSet dataSet, string[] tableNames,
                params OleDbParameter[] commandParameters)
            {
                FillDataset(connection, null, commandType, commandText, dataSet, tableNames, commandParameters);
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  FillDataset(conn, "GetOrders", ds, new string[] {"orders"}, 24, 36);
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            public static void FillDataset(OleDbConnection connection, string spName,
                DataSet dataSet, string[] tableNames,
                params object[] parameterValues)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (dataSet == null) throw new ArgumentNullException("dataSet");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames);
                }
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset and takes no parameters) against the provided OleDbTransaction.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            public static void FillDataset(OleDbTransaction transaction, CommandType commandType,
                string commandText,
                DataSet dataSet, string[] tableNames)
            {
                FillDataset(transaction, commandType, commandText, dataSet, tableNames, null);
            }

            /// <summary>
            /// Execute a OleDbCommand (that returns a resultset) against the specified OleDbTransaction
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            public static void FillDataset(OleDbTransaction transaction, CommandType commandType,
                string commandText, DataSet dataSet, string[] tableNames,
                params OleDbParameter[] commandParameters)
            {
                FillDataset(transaction.Connection, transaction, commandType, commandText, dataSet, tableNames, commandParameters);
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified
            /// OleDbTransaction using the provided parameter values.  This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <remarks>
            /// This method provides no access to output parameters or the stored procedure's return value parameter.
            ///
            /// e.g.: 
            ///  FillDataset(trans, "GetOrders", ds, new string[]{"orders"}, 24, 36);
            /// </remarks>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
            public static void FillDataset(OleDbTransaction transaction, string spName,
                DataSet dataSet, string[] tableNames,
                params object[] parameterValues)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (dataSet == null) throw new ArgumentNullException("dataSet");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If we receive parameter values, we need to figure out where they go
                if ((parameterValues != null) && (parameterValues.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Assign the provided values to these parameters based on parameter order
                    AssignParameterValues(commandParameters, parameterValues);

                    // Call the overload that takes an array of OleDbParameters
                    FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
                }
                else
                {
                    // Otherwise we can just call the SP without params
                    FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames);
                }
            }

            /// <summary>
            /// Private helper method that execute a OleDbCommand (that returns a resultset) against the specified OleDbTransaction and OleDbConnection
            /// using the provided parameters.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  FillDataset(conn, trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new OleDbParameter("@prodid", 24));
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection</param>
            /// <param name="transaction">A valid OleDbTransaction</param>
            /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="dataSet">A dataset wich will contain the resultset generated by the command</param>
            /// <param name="tableNames">This array will be used to create table mappings allowing the DataTables to be referenced
            /// by a user defined name (probably the actual table name)
            /// </param>
            /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
            private static void FillDataset(OleDbConnection connection, OleDbTransaction transaction, CommandType commandType,
                string commandText, DataSet dataSet, string[] tableNames,
                params OleDbParameter[] commandParameters)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (dataSet == null) throw new ArgumentNullException("dataSet");

                // Create a command and prepare it for execution
                OleDbCommand command = new OleDbCommand();
                bool mustCloseConnection = false;
                PrepareCommand(command, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);

                // Create the DataAdapter & DataSet
                using (OleDbDataAdapter dataAdapter = new OleDbDataAdapter(command))
                {

                    // Add the table mappings specified by the user
                    if (tableNames != null && tableNames.Length > 0)
                    {
                        string tableName = "Table";
                        for (int index = 0; index < tableNames.Length; index++)
                        {
                            if (tableNames[index] == null || tableNames[index].Length == 0) throw new ArgumentException("The tableNames parameter must contain a list of tables, a value was provided as null or empty string.", "tableNames");
                            dataAdapter.TableMappings.Add(tableName, tableNames[index]);
                            tableName += (index + 1).ToString();
                        }
                    }

                    // Fill the DataSet using default values for DataTable names, etc
                    dataAdapter.Fill(dataSet);

                    // Detach the OleDbParameters from the command object, so they can be used again
                    command.Parameters.Clear();
                }

                if (mustCloseConnection)
                    connection.Close();
            }
            #endregion

            #region UpdateDataset
            /// <summary>
            /// Executes the respective command for each inserted, updated, or deleted row in the DataSet.
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  UpdateDataset(conn, insertCommand, deleteCommand, updateCommand, dataSet, "Order");
            /// </remarks>
            /// <param name="insertCommand">A valid transact-SQL statement or stored procedure to insert new records into the data source</param>
            /// <param name="deleteCommand">A valid transact-SQL statement or stored procedure to delete records from the data source</param>
            /// <param name="updateCommand">A valid transact-SQL statement or stored procedure used to update records in the data source</param>
            /// <param name="dataSet">The DataSet used to update the data source</param>
            /// <param name="tableName">The DataTable used to update the data source.</param>
            public static void UpdateDataset(OleDbCommand insertCommand, OleDbCommand deleteCommand, OleDbCommand updateCommand, DataSet dataSet, string tableName)
            {
                if (insertCommand == null) throw new ArgumentNullException("insertCommand");
                if (deleteCommand == null) throw new ArgumentNullException("deleteCommand");
                if (updateCommand == null) throw new ArgumentNullException("updateCommand");
                if (tableName == null || tableName.Length == 0) throw new ArgumentNullException("tableName");

                // Create a OleDbDataAdapter, and dispose of it after we are done
                using (OleDbDataAdapter dataAdapter = new OleDbDataAdapter())
                {
                    // Set the data adapter commands
                    dataAdapter.UpdateCommand = updateCommand;
                    dataAdapter.InsertCommand = insertCommand;
                    dataAdapter.DeleteCommand = deleteCommand;

                    // Update the dataset changes in the data source
                    dataAdapter.Update(dataSet, tableName);

                    // Commit all the changes made to the DataSet
                    dataSet.AcceptChanges();
                }
            }
            #endregion

            #region CreateCommand
            /// <summary>
            /// Simplify the creation of a Sql command object by allowing
            /// a stored procedure and optional parameters to be provided
            /// </summary>
            /// <remarks>
            /// e.g.: 
            ///  OleDbCommand command = CreateCommand(conn, "AddCustomer", "CustomerID", "CustomerName");
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="sourceColumns">An array of string to be assigned as the source columns of the stored procedure parameters</param>
            /// <returns>A valid OleDbCommand object</returns>
            public static OleDbCommand CreateCommand(OleDbConnection connection, string spName, params string[] sourceColumns)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // Create a OleDbCommand
                OleDbCommand cmd = new OleDbCommand(spName, connection);
                cmd.CommandType = CommandType.StoredProcedure;

                // If we receive parameter values, we need to figure out where they go
                if ((sourceColumns != null) && (sourceColumns.Length > 0))
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Assign the provided source columns to these parameters based on parameter order
                    for (int index = 0; index < sourceColumns.Length; index++)
                        commandParameters[index].SourceColumn = sourceColumns[index];

                    // Attach the discovered parameters to the OleDbCommand object
                    AttachParameters(cmd, commandParameters);
                }

                return cmd;
            }
            #endregion

            #region ExecuteNonQueryTypedParams
            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns no resultset) against the database specified in
            /// the connection string using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on row values.
            /// </summary>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQueryTypedParams(String connectionString, String spName, DataRow dataRow)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns no resultset) against the specified OleDbConnection
            /// using the dataRow column values as the stored procedure's parameters values. 
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on row values.
            /// </summary>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQueryTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns no resultset) against the specified
            /// OleDbTransaction using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on row values.
            /// </summary>
            /// <param name="transaction">A valid OleDbTransaction object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>An int representing the number of rows affected by the command</returns>
            public static int ExecuteNonQueryTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // Sf the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
                }
            }
            #endregion

            #region ExecuteDatasetTypedParams
            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the database specified in
            /// the connection string using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on row values.
            /// </summary>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDatasetTypedParams(string connectionString, String spName, DataRow dataRow)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                //If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the dataRow column values as the store procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on row values.
            /// </summary>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDatasetTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbTransaction
            /// using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on row values.
            /// </summary>
            /// <param name="transaction">A valid OleDbTransaction object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>A dataset containing the resultset generated by the command</returns>
            public static DataSet ExecuteDatasetTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
                }
            }

            #endregion

            #region ExecuteReaderTypedParams
            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the database specified in
            /// the connection string using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReaderTypedParams(String connectionString, String spName, DataRow dataRow)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
                }
            }


            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbConnection
            /// using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReaderTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a resultset) against the specified OleDbTransaction
            /// using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <param name="transaction">A valid OleDbTransaction object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>A OleDbDataReader containing the resultset generated by the command</returns>
            public static OleDbDataReader ExecuteReaderTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName);
                }
            }
            #endregion

            #region ExecuteScalarTypedParams
            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a 1x1 resultset) against the database specified in
            /// the connection string using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalarTypedParams(String connectionString, String spName, DataRow dataRow)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connectionString, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a 1x1 resultset) against the specified OleDbConnection
            /// using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalarTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName);
                }
            }

            /// <summary>
            /// Execute a stored procedure via a OleDbCommand (that returns a 1x1 resultset) against the specified OleDbTransaction
            /// using the dataRow column values as the stored procedure's parameters values.
            /// This method will query the database to discover the parameters for the
            /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
            /// </summary>
            /// <param name="transaction">A valid OleDbTransaction object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values.</param>
            /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
            public static object ExecuteScalarTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
            {
                if (transaction == null) throw new ArgumentNullException("transaction");
                if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                // If the row has values, the store procedure parameters must be initialized
                if (dataRow != null && dataRow.ItemArray.Length > 0)
                {
                    // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                    OleDbParameter[] commandParameters = AccessHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

                    // Set the parameters values
                    AssignParameterValues(commandParameters, dataRow);

                    return AccessHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
                }
                else
                {
                    return AccessHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
                }
            }
            #endregion

        }

        /// <summary>
        /// AccessHelperParameterCache provides functions to leverage a static cache of procedure parameters, and the
        /// ability to discover parameters for stored procedures at run-time.
        /// </summary>
        public sealed class AccessHelperParameterCache
        {
            #region private methods, variables, and constructors

            //Since this class provides only static methods, make the default constructor private to prevent
            //instances from being created with "new AccessHelperParameterCache()"
            private AccessHelperParameterCache() { }

            private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());

            /// <summary>
            /// Resolve at run time the appropriate set of OleDbParameters for a stored procedure
            /// </summary>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="includeReturnValueParameter">Whether or not to include their return value parameter</param>
            /// <returns>The parameter array discovered.</returns>
            private static OleDbParameter[] DiscoverSpParameterSet(OleDbConnection connection, string spName, bool includeReturnValueParameter)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                OleDbCommand cmd = new OleDbCommand(spName, connection);
                cmd.CommandType = CommandType.StoredProcedure;

                connection.Open();
                OleDbCommandBuilder.DeriveParameters(cmd);
                connection.Close();

                if (!includeReturnValueParameter)
                {
                    cmd.Parameters.RemoveAt(0);
                }

                OleDbParameter[] discoveredParameters = new OleDbParameter[cmd.Parameters.Count];

                cmd.Parameters.CopyTo(discoveredParameters, 0);

                // Init the parameters with a DBNull value
                foreach (OleDbParameter discoveredParameter in discoveredParameters)
                {
                    discoveredParameter.Value = DBNull.Value;
                }
                return discoveredParameters;
            }

            /// <summary>
            /// Deep copy of cached OleDbParameter array
            /// </summary>
            /// <param name="originalParameters"></param>
            /// <returns></returns>
            private static OleDbParameter[] CloneParameters(OleDbParameter[] originalParameters)
            {
                OleDbParameter[] clonedParameters = new OleDbParameter[originalParameters.Length];

                for (int i = 0, j = originalParameters.Length; i < j; i++)
                {
                    clonedParameters[i] = (OleDbParameter)((ICloneable)originalParameters[i]).Clone();
                }

                return clonedParameters;
            }

            #endregion private methods, variables, and constructors

            #region caching functions

            /// <summary>
            /// Add parameter array to the cache
            /// </summary>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <param name="commandParameters">An array of SqlParamters to be cached</param>
            public static void CacheParameterSet(string connectionString, string commandText, params OleDbParameter[] commandParameters)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");

                string hashKey = connectionString + ":" + commandText;

                paramCache[hashKey] = commandParameters;
            }

            /// <summary>
            /// Retrieve a parameter array from the cache
            /// </summary>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="commandText">The stored procedure name or T-SQL command</param>
            /// <returns>An array of SqlParamters</returns>
            public static OleDbParameter[] GetCachedParameterSet(string connectionString, string commandText)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");

                string hashKey = connectionString + ":" + commandText;

                OleDbParameter[] cachedParameters = paramCache[hashKey] as OleDbParameter[];
                if (cachedParameters == null)
                {
                    return null;
                }
                else
                {
                    return CloneParameters(cachedParameters);
                }
            }

            #endregion caching functions

            #region Parameter Discovery Functions

            /// <summary>
            /// Retrieves the set of OleDbParameters appropriate for the stored procedure
            /// </summary>
            /// <remarks>
            /// This method will query the database for this information, and then store it in a cache for future requests.
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <returns>An array of OleDbParameters</returns>
            public static OleDbParameter[] GetSpParameterSet(string connectionString, string spName)
            {
                return GetSpParameterSet(connectionString, spName, false);
            }

            /// <summary>
            /// Retrieves the set of OleDbParameters appropriate for the stored procedure
            /// </summary>
            /// <remarks>
            /// This method will query the database for this information, and then store it in a cache for future requests.
            /// </remarks>
            /// <param name="connectionString">A valid connection string for a OleDbConnection</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="includeReturnValueParameter">A bool value indicating whether the return value parameter should be included in the results</param>
            /// <returns>An array of OleDbParameters</returns>
            public static OleDbParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
            {
                if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    return GetSpParameterSetInternal(connection, spName, includeReturnValueParameter);
                }
            }

            /// <summary>
            /// Retrieves the set of OleDbParameters appropriate for the stored procedure
            /// </summary>
            /// <remarks>
            /// This method will query the database for this information, and then store it in a cache for future requests.
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <returns>An array of OleDbParameters</returns>
            internal static OleDbParameter[] GetSpParameterSet(OleDbConnection connection, string spName)
            {
                return GetSpParameterSet(connection, spName, false);
            }

            /// <summary>
            /// Retrieves the set of OleDbParameters appropriate for the stored procedure
            /// </summary>
            /// <remarks>
            /// This method will query the database for this information, and then store it in a cache for future requests.
            /// </remarks>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="includeReturnValueParameter">A bool value indicating whether the return value parameter should be included in the results</param>
            /// <returns>An array of OleDbParameters</returns>
            internal static OleDbParameter[] GetSpParameterSet(OleDbConnection connection, string spName, bool includeReturnValueParameter)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                using (OleDbConnection clonedConnection = (OleDbConnection)((ICloneable)connection).Clone())
                {
                    return GetSpParameterSetInternal(clonedConnection, spName, includeReturnValueParameter);
                }
            }

            /// <summary>
            /// Retrieves the set of OleDbParameters appropriate for the stored procedure
            /// </summary>
            /// <param name="connection">A valid OleDbConnection object</param>
            /// <param name="spName">The name of the stored procedure</param>
            /// <param name="includeReturnValueParameter">A bool value indicating whether the return value parameter should be included in the results</param>
            /// <returns>An array of OleDbParameters</returns>
            private static OleDbParameter[] GetSpParameterSetInternal(OleDbConnection connection, string spName, bool includeReturnValueParameter)
            {
                if (connection == null) throw new ArgumentNullException("connection");
                if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");

                string hashKey = connection.ConnectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter" : "");

                OleDbParameter[] cachedParameters;

                cachedParameters = paramCache[hashKey] as OleDbParameter[];
                if (cachedParameters == null)
                {
                    OleDbParameter[] spParameters = DiscoverSpParameterSet(connection, spName, includeReturnValueParameter);
                    paramCache[hashKey] = spParameters;
                    cachedParameters = spParameters;
                }

                return CloneParameters(cachedParameters);
            }

            #endregion Parameter Discovery Functions

        }
    }

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  • 原文地址:https://www.cnblogs.com/nogodsend/p/2196932.html
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