OracleHelper 帮助类

using System;
using System.Data;
using System.Xml;
using System.Collections;
using Common;
using System.Data.OleDb;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
//使用ODP.NET访问oracle效率比data.OracleClient高


namespace DAL
{
    /// <summary>
    /// The OracleHelper class is intended to encapsulate high performance, scalable best practices for 
    /// common uses of OracleClient
    /// </summary>
    public sealed class OracleHelper
    {
        public static string ConnectionString = GlobalVar.GetDBConnectString();
        public static string ConnectionPACSString = GlobalVar.GetDBConnectStringPACS();
        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 Oracle 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;//使用Oracle.DataAccess时，注释掉这句就可以了，如果是Data.OracleClient不用注释掉

            }

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

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

        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);
                    }
                }
            }
        }

        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++;
            }
        }

        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];
                }
            }
        }

        #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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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();
                // 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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();

                // 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 = OLEDBHelperParameterCache.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 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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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;
            cmd.Transaction = transaction;
            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 = OLEDBHelperParameterCache.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 ExecuteReader

        /// <summary>
        /// This enum is used to indicate whether the connection was provided by the caller, or created by OLEDBHelper, so that
        /// we can set the appropriate CommandBehavior when calling ExecuteReader()
        /// </summary>
        private enum OleDbConnectionOwnership
        {
            /// <summary>Connection is owned and managed by OLEDBHelper</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-Oracle 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 OLEDBHelper</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 OracleReader can�t set its values. 
                // When this happen, the parameters can�t 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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 OracleDatReader, 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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-Oracle 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-Oracle 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 OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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-Oracle 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 OracleParamters 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 = OLEDBHelperParameterCache.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-Oracle 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 OracleParamters 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]);
                        //程飞对应网上所说，在下面加上了
                        tableName = "Table";
                        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-Oracle statement or stored procedure to insert new records into the data source</param>
        /// <param name="deleteCommand">A valid transact-Oracle statement or stored procedure to delete records from the data source</param>
        /// <param name="updateCommand">A valid transact-Oracle 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 Oracle 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 = OLEDBHelperParameterCache.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 = OLEDBHelperParameterCache.GetSpParameterSet(connectionString, spName);

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

                return OLEDBHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connection, spName);

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

                return OLEDBHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

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

                return OLEDBHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connectionString, spName);

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

                return OLEDBHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connection, spName);

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

                return OLEDBHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

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

                return OLEDBHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connectionString, spName);

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

                return OLEDBHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connection, spName);

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

                return OLEDBHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

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

                return OLEDBHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connectionString, spName);

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

                return OLEDBHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(connection, spName);

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

                return OLEDBHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return OLEDBHelper.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 = OLEDBHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

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

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

    }


    /// <summary>
    /// OLEDBHelperParameterCache 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 OLEDBHelperParameterCache
    {
        #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 OLEDBHelperParameterCache()"
        private OLEDBHelperParameterCache() { }

        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-Oracle command</param>
        /// <param name="commandParameters">An array of OracleParamters 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-Oracle command</param>
        /// <returns>An array of OracleParamters</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

    }
}