OracleHelper

发布日期:2014-03-08 21:32:05
//===============================================================================
// 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 = 0, 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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                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 > 0)) 
                        {
                                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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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 > 0)) 
                        {
                                //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[0].Direction)                              
                                                cmd.Parameters.RemoveAt(0);                                                                     
                                }
                        
                                OracleParameter[] discoveredParameters = new OracleParameter[cmd.Parameters.Count];


                                cmd.Parameters.CopyTo(discoveredParameters, 0);


                                return discoveredParameters;
                        }
                }


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


                        for (int i = 0, 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


        }
}