数据库连接类oracleHelper

 //===============================================================================
 // OracleHelper based on Microsoft Data Access Application Block (DAAB) for .NET
 // http://msdn.microsoft.com/library/en-us/dnbda/html/daab-rm.asp
 //
 // OracleHelper.cs
 //
 // This file contains the implementations of the OracleHelper and OracleHelperParameterCache
 // classes.
 //
 // The DAAB for MS .NET Provider for Oracle has been tested in the context of this Nile implementation,
 // but has not undergone the generic functional testing that the SQL version has gone through.
 // You can use it in other .NET applications using Oracle databases.  For complete docs explaining how to use
 // and how it's built go to the originl appblock link.
 // For this sample, the code resides in the Nile namespaces not the Microsoft.ApplicationBlocks namespace
 //==============================================================================

 using System;
 using System.Data;
 using System.Xml;
 using System.Data.OracleClient;
 using System.Collections;

 namespace Microsoft.ApplicationBlocks.Data
 {
     /// <summary>
     /// The OracleHelper class is intended to encapsulate high performance, scalable best practices for
     /// common uses of OracleClient.
     /// </summary>
     public sealed class OracleHelper
     {
         #region private utility methods & constructors

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

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

                 command.Parameters.Add(p);
             }
         }

         /// <summary>
         /// This method assigns an array of values to an array of OracleParameters.
         /// </summary>
         /// <param name="commandParameters">array of OracleParameters to be assigned values</param>
         /// <param name="parameterValues">array of objects holding the values to be assigned</param>
         private static void AssignParameterValues(OracleParameter[] 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 OracleParameters, assigning the values from the corresponding position in the
             //value array
             for (int i = , j = commandParameters.Length; i < j; i++)
             {
                 commandParameters[i].Value = parameterValues[i];
             }
         }

         /// <summary>
         /// This method opens (if necessary) and assigns a connection, transaction, command type and parameters
         /// to the provided command.
         /// </summary>
         /// <param name="command">the OracleCommand to be prepared</param>
         /// <param name="connection">a valid OracleConnection, on which to execute this command</param>
         /// <param name="transaction">a valid OracleTransaction, or 'null'</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters to be associated with the command or 'null' if no parameters are required</param>
         private static void PrepareCommand(OracleCommand command, OracleConnection connection, OracleTransaction transaction, CommandType commandType, string commandText, OracleParameter[] commandParameters)
         {
             //if the provided connection is not open, we will open it
             if (connection.State != ConnectionState.Open)
             {
                 connection.Open();
             }

             //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)
             {
                 command.Transaction = transaction;
             }

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

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

             return;
         }

         #endregion private utility methods & constructors

         #region ExecuteNonQuery

         /// <summary>
         /// Execute an OracleCommand (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 an OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>an int representing the number of rows affected by the command</returns>
         public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteNonQuery(connectionString, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (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 OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connectionString">a valid connection string for an OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters 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 OracleParameter[] commandParameters)
         {
             //create & open an OracleConnection, and dispose of it after we are done.
             using (OracleConnection cn = new OracleConnection(connectionString))
             {
                 cn.Open();

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

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (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 an OracleConnection</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(string connectionString, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.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 OracleParameters
                 return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
             }
             //otherwise we can just call the SP without params
             else
             {
                 return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
             }
         }

         /// <summary>
         /// Execute an OracleCommand (that returns no resultset and takes no parameters) against the provided OracleConnection.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>an int representing the number of rows affected by the command</returns>
         public static int ExecuteNonQuery(OracleConnection connection, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteNonQuery(connection, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (that returns no resultset) against the specified OracleConnection
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>an int representing the number of rows affected by the command</returns>
         public static int ExecuteNonQuery(OracleConnection connection, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, connection, (OracleTransaction)null, commandType, commandText, commandParameters);

             //finally, execute the command.
             return cmd.ExecuteNonQuery();
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns no resultset) against the specified OracleConnection
         /// 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 OracleConnection</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(OracleConnection connection, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);

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

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

         /// <summary>
         /// Execute an OracleCommand (that returns no resultset and takes no parameters) against the provided OracleTransaction.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>an int representing the number of rows affected by the command</returns>
         public static int ExecuteNonQuery(OracleTransaction transaction, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteNonQuery(transaction, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (that returns no resultset) against the specified OracleTransaction
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>an int representing the number of rows affected by the command</returns>
         public static int ExecuteNonQuery(OracleTransaction transaction, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

             //finally, execute the command.
             return cmd.ExecuteNonQuery();
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns no resultset) against the specified
         /// OracleTransaction 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 OracleTransaction</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(OracleTransaction transaction, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);

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

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

         #endregion ExecuteNonQuery

         #region ExecuteDataSet

         /// <summary>
         /// Execute an OracleCommand (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 an OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>a dataset containing the resultset generated by the command</returns>
         public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteDataset(connectionString, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (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 OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connectionString">a valid connection string for an OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters 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 OracleParameter[] commandParameters)
         {
             //create & open an OracleConnection, and dispose of it after we are done.
             using (OracleConnection cn = new OracleConnection(connectionString))
             {
                 cn.Open();

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

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a resultset) against the database specified in
         /// the conneciton 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 an OracleConnection</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 we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.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 OracleParameters
                 return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
             }
                 //otherwise we can just call the SP without params
             else
             {
                 return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
             }
         }

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

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset) against the specified OracleConnection
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>a dataset containing the resultset generated by the command</returns>
         public static DataSet ExecuteDataset(OracleConnection connection, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, connection, (OracleTransaction)null, commandType, commandText, commandParameters);

             //create the DataAdapter & DataSet
             OracleDataAdapter da = new OracleDataAdapter(cmd);
             DataSet ds = new DataSet();

             //fill the DataSet using default values for DataTable names, etc.
             da.Fill(ds);

             //return the dataset
             return ds;
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a resultset) against the specified OracleConnection
         /// 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 OracleConnection</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(OracleConnection connection, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);

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

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

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

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset) against the specified OracleTransaction
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>a dataset containing the resultset generated by the command</returns>
         public static DataSet ExecuteDataset(OracleTransaction transaction, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

             //create the DataAdapter & DataSet
             OracleDataAdapter da = new OracleDataAdapter(cmd);
             DataSet ds = new DataSet();

             //fill the DataSet using default values for DataTable names, etc.
             da.Fill(ds);

             //return the dataset
             return ds;
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a resultset) against the specified
         /// OracleTransaction 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 OracleTransaction</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(OracleTransaction transaction, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);

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

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

         #endregion ExecuteDataSet

         #region ExecuteReader

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

         /// <summary>
         /// Create and prepare an OracleCommand, 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 OracleConnection, on which to execute this command</param>
         /// <param name="transaction">a valid OracleTransaction, or 'null'</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters 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 OracleHelper</param>
         /// <returns>OracleDataReader containing the results of the command</returns>
         private static OracleDataReader ExecuteReader(OracleConnection connection, OracleTransaction transaction, CommandType commandType, string commandText, OracleParameter[] commandParameters, OracleConnectionOwnership connectionOwnership)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);

             //create a reader
             OracleDataReader dr;

             // call ExecuteReader with the appropriate CommandBehavior
             if (connectionOwnership == OracleConnectionOwnership.External)
             {
                 dr = cmd.ExecuteReader();
             }
             else
             {
                 dr = cmd.ExecuteReader((CommandBehavior)((int)CommandBehavior.CloseConnection));
             }

             return (OracleDataReader) dr;
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset and takes no parameters) against the database specified in
         /// the connection string.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  OracleDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
         /// </remarks>
         /// <param name="connectionString">a valid connection string for an OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>an OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteReader(connectionString, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset) against the database specified in the connection string
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  OracleDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connectionString">a valid connection string for an OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>an OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create & open an OraclebConnection
             OracleConnection cn = new OracleConnection(connectionString);
             cn.Open();

             try
             {
                 //call the private overload that takes an internally owned connection in place of the connection string
                 return ExecuteReader(cn, null, commandType, commandText, commandParameters, OracleConnectionOwnership.Internal);
             }
             catch
             {
                 //if we fail to return the OracleDataReader, we need to close the connection ourselves
                 cn.Close();
                 throw;
             }
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (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.:
         ///  OracleDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
         /// </remarks>
         /// <param name="connectionString">a valid connection string for an OracleConnection</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 OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.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 OracleParameters
                 return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
             }
             //otherwise we can just call the SP without params
             else
             {
                 return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
             }
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset and takes no parameters) against the provided OracleConnection.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  OracleDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>an OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(OracleConnection connection, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteReader(connection, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset) against the specified OracleConnection
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  OracleDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>an OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(OracleConnection connection, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //pass through the call to the private overload using a null transaction value and an externally owned connection
             return ExecuteReader(connection, (OracleTransaction)null, commandType, commandText, commandParameters, OracleConnectionOwnership.External);
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a resultset) against the specified OracleConnection
         /// 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.:
         ///  OracleDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</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 OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(OracleConnection connection, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);

                 AssignParameterValues(commandParameters, parameterValues);

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

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset and takes no parameters) against the provided OracleTransaction.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  OracleDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <returns>an OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(OracleTransaction transaction, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteReader(transaction, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a resultset) against the specified OracleTransaction
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///   OracleDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or PL/SQL command</param>
         /// <param name="commandParameters">an array of OracleParameters used to execute the command</param>
         /// <returns>an OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(OracleTransaction transaction, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //pass through to private overload, indicating that the connection is owned by the caller
             return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, OracleConnectionOwnership.External);
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a resultset) against the specified
         /// OracleTransaction 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.:
         ///  OracleDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</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 OracleDataReader containing the resultset generated by the command</returns>
         public static OracleDataReader ExecuteReader(OracleTransaction transaction, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);

                 AssignParameterValues(commandParameters, parameterValues);

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

         #endregion ExecuteReader

         #region ExecuteScalar

         /// <summary>
         /// Execute an OracleCommand (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 an OracleConnection</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 OracleParameters
             return ExecuteScalar(connectionString, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (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 OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connectionString">a valid connection string for an OracleConnection</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 OracleParameters 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 OracleParameter[] commandParameters)
         {
             //create & open an OracleConnection, and dispose of it after we are done.
             using (OracleConnection cn = new OracleConnection(connectionString))
             {
                 cn.Open();

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

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a 1x1 resultset) against the database specified in
         /// the conneciton 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 an OracleConnection</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 we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.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 OracleParameters
                 return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
             }
                 //otherwise we can just call the SP without params
             else
             {
                 return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
             }
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a 1x1 resultset and takes no parameters) against the provided OracleConnection.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</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(OracleConnection connection, CommandType commandType, string commandText)
         {
             //pass through the call providing null for the set of OracleParameters
             return ExecuteScalar(connection, commandType, commandText, (OracleParameter[])null);
         }

         /// <summary>
         /// Execute an OracleCommand (that returns a 1x1 resultset) against the specified OracleConnection
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="connection">a valid OracleConnection</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or T-OleDb command</param>
         /// <param name="commandParameters">an array of OracleParameters 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(OracleConnection connection, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, connection, (OracleTransaction)null, commandType, commandText, commandParameters);

             //execute the command & return the results
             return cmd.ExecuteScalar();
         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a 1x1 resultset) against the specified OracleConnection
         /// 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 OracleConnection</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(OracleConnection connection, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);

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

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

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

         /// <summary>
         /// Execute an OracleCommand (that returns a 1x1 resultset) against the specified OracleTransaction
         /// using the provided parameters.
         /// </summary>
         /// <remarks>
         /// e.g.:
         ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new OracleParameter("@prodid", 24));
         /// </remarks>
         /// <param name="transaction">a valid OracleTransaction</param>
         /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
         /// <param name="commandText">the stored procedure name or T-OleDb command</param>
         /// <param name="commandParameters">an array of OracleParameters 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(OracleTransaction transaction, CommandType commandType, string commandText, params OracleParameter[] commandParameters)
         {
             //create a command and prepare it for execution
             OracleCommand cmd = new OracleCommand();
             PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

             //execute the command & return the results
             return cmd.ExecuteScalar();

         }

         /// <summary>
         /// Execute a stored procedure via an OracleCommand (that returns a 1x1 resultset) against the specified
         /// OracleTransaction 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 OracleTransaction</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(OracleTransaction transaction, string spName, params object[] parameterValues)
         {
             //if we got parameter values, we need to figure out where they go
             if ((parameterValues != null) && (parameterValues.Length > ))
             {
                 //pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
                 OracleParameter[] commandParameters = OracleHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);

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

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

         #endregion ExecuteScalar
     }

     /// <summary>
     /// OracleHelperParameterCache 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 OracleHelperParameterCache
     {
         #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 OracleHelperParameterCache()".
         private OracleHelperParameterCache() {}

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

         /// <summary>
         /// resolve at run-time the appropriate set of OracleParameters for a stored procedure
         /// </summary>
         /// <param name="connectionString">a valid connection string for an OracleConnection</param>
         /// <param name="spName">the name of the stored procedure</param>
         /// <param name="includeReturnValueParameter">whether or not to include ther return value parameter</param>
         /// <returns></returns>
         private static OracleParameter[] DiscoverSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
         {
             using (OracleConnection cn = new OracleConnection(connectionString))
             using (OracleCommand cmd = new OracleCommand(spName,cn))
             {
                 cn.Open();
                 cmd.CommandType = CommandType.StoredProcedure;

                 OracleCommandBuilder.DeriveParameters(cmd);

                 if (!includeReturnValueParameter)
                 {
                     if (ParameterDirection.ReturnValue == cmd.Parameters[].Direction)
                         cmd.Parameters.RemoveAt();
                 }

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

                 cmd.Parameters.CopyTo(discoveredParameters, );

                 return discoveredParameters;
             }
         }

         //deep copy of cached OracleParameter array
         private static OracleParameter[] CloneParameters(OracleParameter[] originalParameters)
         {
             OracleParameter[] clonedParameters = new OracleParameter[originalParameters.Length];

             for (int i = , j = originalParameters.Length; i < j; i++)
             {
                 clonedParameters[i] = (OracleParameter)((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 an OracleConnection</param>
         /// <param name="commandText">the stored procedure name or T-OleDb command</param>
         /// <param name="commandParameters">an array of OracleParameters to be cached</param>
         public static void CacheParameterSet(string connectionString, string commandText, params OracleParameter[] commandParameters)
         {
             string hashKey = connectionString + ":" + commandText;

             paramCache[hashKey] = commandParameters;
         }

         /// <summary>
         /// retrieve a parameter array from the cache
         /// </summary>
         /// <param name="connectionString">a valid connection string for an OracleConnection</param>
         /// <param name="commandText">the stored procedure name or T-OleDb command</param>
         /// <returns>an array of OracleParameters</returns>
         public static OracleParameter[] GetCachedParameterSet(string connectionString, string commandText)
         {
             string hashKey = connectionString + ":" + commandText;

             OracleParameter[] cachedParameters = (OracleParameter[])paramCache[hashKey];

             if (cachedParameters == null)
             {
                 return null;
             }
             else
             {
                 return CloneParameters(cachedParameters);
             }
         }

         #endregion caching functions

         #region Parameter Discovery Functions

         /// <summary>
         /// Retrieves the set of OracleParameters 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 an OracleConnection</param>
         /// <param name="spName">the name of the stored procedure</param>
         /// <returns>an array of OracleParameters</returns>
         public static OracleParameter[] GetSpParameterSet(string connectionString, string spName)
         {
             return GetSpParameterSet(connectionString, spName, false);
         }

         /// <summary>
         /// Retrieves the set of OracleParameters 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 an OracleConnection</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 OracleParameters</returns>
         public static OracleParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
         {
             string hashKey = connectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter":"");

             OracleParameter[] cachedParameters;

             cachedParameters = (OracleParameter[])paramCache[hashKey];

             if (cachedParameters == null)
             {
                 cachedParameters = (OracleParameter[])(paramCache[hashKey] = DiscoverSpParameterSet(connectionString, spName, includeReturnValueParameter));
             }

             return CloneParameters(cachedParameters);
         }

         #endregion Parameter Discovery Functions

     }
 }