sqlhelper for access

 using System;

using System.Data;
using System.Xml;
using System.Data.OleDb;
using System.Collections;
using System.Configuration;
namespace Microsoft.ApplicationBlocks.Data
{
    /// <summary>
    /// The SqlHelper class is intended to encapsulate high performance, scalable best practices for 
    /// common uses of OleDbClient
    /// </summary>
    public sealed class SqlHelper
    {
       
        public static readonly string Conn = System.Configuration.ConfigurationManager.AppSettings["Conn"].ToString() + System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["dbPath"]) + ";"; 
        public static readonly string Conn2 = System.Configuration.ConfigurationManager.AppSettings["Conn2"].ToString() + System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["dbPath2"]) + ";"; 
       
        #region private utility methods & constructors
     
        private SqlHelper() { }
       
        private static void AttachParameters(OleDbCommand command, OleDbParameter[] commandParameters)
        {
            if (command == null) throw new ArgumentNullException("command");
            if (commandParameters != null)
            {
                foreach (OleDbParameter p in commandParameters)
                {
                    if (p != null)
                    {
                        // Check for derived output value with no value assigned
                        if ((p.Direction == ParameterDirection.InputOutput ||
                         p.Direction == ParameterDirection.Input) &&
                         (p.Value == null))
                        {
                            p.Value = DBNull.Value;
                        }
                        command.Parameters.Add(p);
                    }
                }
            }
        }
       
        private static void AssignParameterValues(OleDbParameter[] commandParameters, DataRow dataRow)
        {
            if ((commandParameters == null) || (dataRow == null))
            {
                // Do nothing if we get no data
                return;
            }
            int i = 0;
            // Set the parameters values
            foreach (OleDbParameter commandParameter in commandParameters)
            {
                // Check the parameter name
                if (commandParameter.ParameterName == null ||
                 commandParameter.ParameterName.Length <= 1)
                    throw new Exception(
                     string.Format(
                      "Please provide a valid parameter name on the parameter #{0}, the ParameterName property has the following value: '{1}'.",
                      i, commandParameter.ParameterName));
                if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1)
                    commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];
                i++;
            }
        }
        
        private static void AssignParameterValues(OleDbParameter[] commandParameters, object[] parameterValues)
        {
            if ((commandParameters == null) || (parameterValues == null))
            {
                // Do nothing if we get no data
                return;
            }
            // We must have the same number of values as we pave parameters to put them in
            if (commandParameters.Length != parameterValues.Length)
            {
                throw new ArgumentException("Parameter count does not match Parameter Value count.");
            }
            // Iterate through the OleDbParameters, assigning the values from the corresponding position in the 
            // value array
            for (int i = 0, j = commandParameters.Length; i < j; i++)
            {
                // If the current array value derives from IDbDataParameter, then assign its Value property
                if (parameterValues[i] is IDbDataParameter)
                {
                    IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i];
                    if (paramInstance.Value == null)
                    {
                        commandParameters[i].Value = DBNull.Value;
                    }
                    else
                    {
                        commandParameters[i].Value = paramInstance.Value;
                    }
                }
                else if (parameterValues[i] == null)
                {
                    commandParameters[i].Value = DBNull.Value;
                }
                else
                {
                    commandParameters[i].Value = parameterValues[i];
                }
            }
        }
      
        private static void PrepareCommand(OleDbCommand command, OleDbConnection connection, OleDbTransaction transaction, CommandType commandType, string commandText, OleDbParameter[] commandParameters, out bool mustCloseConnection)
        {
            if (command == null) throw new ArgumentNullException("command");
            if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");
            // If the provided connection is not open, we will open it
            if (connection.State != ConnectionState.Open)
            {
                mustCloseConnection = true;
                connection.Open();
            }
            else
            {
                mustCloseConnection = false;
            }
            // Associate the connection with the command
            command.Connection = connection;
            // Set the command text (stored procedure name or OleDb statement)
            command.CommandText = commandText;
            // If we were provided a transaction, assign it
            if (transaction != null)
            {
                if (transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                command.Transaction = transaction;
            }
            // Set the command type
            command.CommandType = commandType;
            // Attach the command parameters if they are provided
            if (commandParameters != null)
            {
                AttachParameters(command, commandParameters);
            }
            return;
        }
        #endregion private utility methods & constructors
        #region ExecuteNonQuery
      
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteNonQuery(connectionString, commandType, commandText, (OleDbParameter[])null);
        }
       
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            // Create & open a OleDbConnection, and dispose of it after we are done
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                // Call the overload that takes a connection in place of the connection string
                return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
            }
        }
       
        public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
            }
        }
    
        public static int ExecuteNonQuery(OleDbConnection connection, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteNonQuery(connection, commandType, commandText, (OleDbParameter[])null);
        }
       
        public static int ExecuteNonQuery(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(cmd, connection, (OleDbTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
            // Finally, execute the command
            int retval = cmd.ExecuteNonQuery();
            // Detach the OleDbParameters from the command object, so they can be used again
            cmd.Parameters.Clear();
            if (mustCloseConnection)
                connection.Close();
            return retval;
        }
        public static int ExecuteNonQuery(OleDbConnection connection, string spName, params object[] parameterValues)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
            }
        }
      
        public static int ExecuteNonQuery(OleDbTransaction transaction, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteNonQuery(transaction, commandType, commandText, (OleDbParameter[])null);
        }
        
        public static int ExecuteNonQuery(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
            // Finally, execute the command
            int retval = cmd.ExecuteNonQuery();
            // Detach the OleDbParameters from the command object, so they can be used again
            cmd.Parameters.Clear();
            return retval;
        }
     
        public static int ExecuteNonQuery(OleDbTransaction transaction, string spName, params object[] parameterValues)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion ExecuteNonQuery
        #region ExecuteDataset
      
        public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteDataset(connectionString, commandType, commandText, (OleDbParameter[])null);
        }
      
        public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            // Create & open a OleDbConnection, and dispose of it after we are done
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                // Call the overload that takes a connection in place of the connection string
                return ExecuteDataset(connection, commandType, commandText, commandParameters);
            }
        }
      
        public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
            }
        }
      
        public static DataSet ExecuteDataset(OleDbConnection connection, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteDataset(connection, commandType, commandText, (OleDbParameter[])null);
        }
      
        public static DataSet ExecuteDataset(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(cmd, connection, (OleDbTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
            // Create the DataAdapter & DataSet
            using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
            {
                DataSet ds = new DataSet();
                // Fill the DataSet using default values for DataTable names, etc
                da.Fill(ds);
                // Detach the OleDbParameters from the command object, so they can be used again
                cmd.Parameters.Clear();
                if (mustCloseConnection)
                    connection.Close();
                // Return the dataset
                return ds;
            }
        }
     
        public static DataSet ExecuteDataset(OleDbConnection connection, string spName, params object[] parameterValues)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
            }
        }
       
        public static DataSet ExecuteDataset(OleDbTransaction transaction, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteDataset(transaction, commandType, commandText, (OleDbParameter[])null);
        }
       
        public static DataSet ExecuteDataset(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
            // Create the DataAdapter & DataSet
            using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
            {
                DataSet ds = new DataSet();
                // Fill the DataSet using default values for DataTable names, etc
                da.Fill(ds);
                // Detach the OleDbParameters from the command object, so they can be used again
                cmd.Parameters.Clear();
                // Return the dataset
                return ds;
            }
        }
      
        public static DataSet ExecuteDataset(OleDbTransaction transaction, string spName, params object[] parameterValues)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion ExecuteDataset
        #region ExecuteReader
        private enum OleDbConnectionOwnership
        {
            /// <summary>Connection is owned and managed by SqlHelper</summary>
            Internal,
            /// <summary>Connection is owned and managed by the caller</summary>
            External
        }
       
        private static OleDbDataReader ExecuteReader(OleDbConnection connection, OleDbTransaction transaction, CommandType commandType, string commandText, OleDbParameter[] commandParameters, OleDbConnectionOwnership connectionOwnership)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            bool mustCloseConnection = false;
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            try
            {
                PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
                // Create a reader
                OleDbDataReader dataReader;
                // Call ExecuteReader with the appropriate CommandBehavior
                if (connectionOwnership == OleDbConnectionOwnership.External)
                {
                    dataReader = cmd.ExecuteReader();
                }
                else
                {
                    dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                }
                // Detach the OleDbParameters from the command object, so they can be used again.
                // HACK: There is a problem here, the output parameter values are fletched 
                // when the reader is closed, so if the parameters are detached from the command
                // then the OleDbReader can磘 set its values. 
                // When this happen, the parameters can磘 be used again in other command.
                bool canClear = true;
                foreach (OleDbParameter commandParameter in cmd.Parameters)
                {
                    if (commandParameter.Direction != ParameterDirection.Input)
                        canClear = false;
                }
                if (canClear)
                {
                    cmd.Parameters.Clear();
                }
                return dataReader;
            }
            catch
            {
                if (mustCloseConnection)
                    connection.Close();
                throw;
            }
        }
      
        public static OleDbDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteReader(connectionString, commandType, commandText, (OleDbParameter[])null);
        }
      
        public static OleDbDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            OleDbConnection connection = null;
            try
            {
                connection = new OleDbConnection(connectionString);
                connection.Open();
                // Call the private overload that takes an internally owned connection in place of the connection string
                return ExecuteReader(connection, null, commandType, commandText, commandParameters, OleDbConnectionOwnership.Internal);
            }
            catch
            {
                // If we fail to return the OleDbDatReader, we need to close the connection ourselves
                if (connection != null) connection.Close();
                throw;
            }
        }
        
        public static OleDbDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                AssignParameterValues(commandParameters, parameterValues);
                return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
            }
        }
       
        public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteReader(connection, commandType, commandText, (OleDbParameter[])null);
        }
       
        public static OleDbDataReader ExecuteReader(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            // Pass through the call to the private overload using a null transaction value and an externally owned connection
            return ExecuteReader(connection, (OleDbTransaction)null, commandType, commandText, commandParameters, OleDbConnectionOwnership.External);
        }
      
        public static OleDbDataReader ExecuteReader(OleDbConnection connection, string spName, params object[] parameterValues)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                AssignParameterValues(commandParameters, parameterValues);
                return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteReader(connection, CommandType.StoredProcedure, spName);
            }
        }
       
        public static OleDbDataReader ExecuteReader(OleDbTransaction transaction, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteReader(transaction, commandType, commandText, (OleDbParameter[])null);
        }
     
        public static OleDbDataReader ExecuteReader(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            // Pass through to private overload, indicating that the connection is owned by the caller
            return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, OleDbConnectionOwnership.External);
        }
      
        public static OleDbDataReader ExecuteReader(OleDbTransaction transaction, string spName, params object[] parameterValues)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                AssignParameterValues(commandParameters, parameterValues);
                return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion ExecuteReader
        #region ExecuteScalar
     
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteScalar(connectionString, commandType, commandText, (OleDbParameter[])null);
        }
     
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            // Create & open a OleDbConnection, and dispose of it after we are done
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                // Call the overload that takes a connection in place of the connection string
                return ExecuteScalar(connection, commandType, commandText, commandParameters);
            }
        }
      
        public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
            }
        }
      
        public static object ExecuteScalar(OleDbConnection connection, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteScalar(connection, commandType, commandText, (OleDbParameter[])null);
        }
    
        public static object ExecuteScalar(OleDbConnection connection, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(cmd, connection, (OleDbTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
            // Execute the command & return the results
            object retval = cmd.ExecuteScalar();
            // Detach the OleDbParameters from the command object, so they can be used again
            cmd.Parameters.Clear();
            if (mustCloseConnection)
                connection.Close();
            return retval;
        }
      
        public static object ExecuteScalar(OleDbConnection connection, string spName, params object[] parameterValues)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
            }
        }
        public static object ExecuteScalar(OleDbTransaction transaction, CommandType commandType, string commandText)
        {
            // Pass through the call providing null for the set of OleDbParameters
            return ExecuteScalar(transaction, commandType, commandText, (OleDbParameter[])null);
        }
    
        public static object ExecuteScalar(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] commandParameters)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            // Create a command and prepare it for execution
            OleDbCommand cmd = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
            // Execute the command & return the results
            object retval = cmd.ExecuteScalar();
            // Detach the OleDbParameters from the command object, so they can be used again
            cmd.Parameters.Clear();
            return retval;
        }
     
        public static object ExecuteScalar(OleDbTransaction transaction, string spName, params object[] parameterValues)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // PPull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion ExecuteScalar
        #region ExecuteXmlReader
      
        public static void FillDataset(string connectionString, CommandType commandType, string commandText, DataSet dataSet, string[] tableNames)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (dataSet == null) throw new ArgumentNullException("dataSet");
            // Create & open a OleDbConnection, and dispose of it after we are done
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                // Call the overload that takes a connection in place of the connection string
                FillDataset(connection, commandType, commandText, dataSet, tableNames);
            }
        }
       
        public static void FillDataset(string connectionString, CommandType commandType,
            string commandText, DataSet dataSet, string[] tableNames,
            params OleDbParameter[] commandParameters)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (dataSet == null) throw new ArgumentNullException("dataSet");
            // Create & open a OleDbConnection, and dispose of it after we are done
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                // Call the overload that takes a connection in place of the connection string
                FillDataset(connection, commandType, commandText, dataSet, tableNames, commandParameters);
            }
        }
       
        public static void FillDataset(string connectionString, string spName,
            DataSet dataSet, string[] tableNames,
            params object[] parameterValues)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (dataSet == null) throw new ArgumentNullException("dataSet");
            // Create & open a OleDbConnection, and dispose of it after we are done
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                // Call the overload that takes a connection in place of the connection string
                FillDataset(connection, spName, dataSet, tableNames, parameterValues);
            }
        }
      
        public static void FillDataset(OleDbConnection connection, CommandType commandType,
            string commandText, DataSet dataSet, string[] tableNames)
        {
            FillDataset(connection, commandType, commandText, dataSet, tableNames, null);
        }
        public static void FillDataset(OleDbConnection connection, CommandType commandType,
            string commandText, DataSet dataSet, string[] tableNames,
            params OleDbParameter[] commandParameters)
        {
            FillDataset(connection, null, commandType, commandText, dataSet, tableNames, commandParameters);
        }
        
        public static void FillDataset(OleDbConnection connection, string spName,
            DataSet dataSet, string[] tableNames,
            params object[] parameterValues)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (dataSet == null) throw new ArgumentNullException("dataSet");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames);
            }
        }
     
        public static void FillDataset(OleDbTransaction transaction, CommandType commandType,
            string commandText,
            DataSet dataSet, string[] tableNames)
        {
            FillDataset(transaction, commandType, commandText, dataSet, tableNames, null);
        }
       
        public static void FillDataset(OleDbTransaction transaction, CommandType commandType,
            string commandText, DataSet dataSet, string[] tableNames,
            params OleDbParameter[] commandParameters)
        {
            FillDataset(transaction.Connection, transaction, commandType, commandText, dataSet, tableNames, commandParameters);
        }
      
        public static void FillDataset(OleDbTransaction transaction, string spName,
            DataSet dataSet, string[] tableNames,
            params object[] parameterValues)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (dataSet == null) throw new ArgumentNullException("dataSet");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Assign the provided values to these parameters based on parameter order
                AssignParameterValues(commandParameters, parameterValues);
                // Call the overload that takes an array of OleDbParameters
                FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
            }
            else
            {
                // Otherwise we can just call the SP without params
                FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames);
            }
        }
      
        private static void FillDataset(OleDbConnection connection, OleDbTransaction transaction, CommandType commandType,
         string commandText, DataSet dataSet, string[] tableNames,
         params OleDbParameter[] commandParameters)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (dataSet == null) throw new ArgumentNullException("dataSet");
            // Create a command and prepare it for execution
            OleDbCommand command = new OleDbCommand();
            bool mustCloseConnection = false;
            PrepareCommand(command, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
            // Create the DataAdapter & DataSet
            using (OleDbDataAdapter dataAdapter = new OleDbDataAdapter(command))
            {
                // Add the table mappings specified by the user
                if (tableNames != null && tableNames.Length > 0)
                {
                    string tableName = "Table";
                    for (int index = 0; index < tableNames.Length; index++)
                    {
                        if (tableNames[index] == null || tableNames[index].Length == 0) throw new ArgumentException("The tableNames parameter must contain a list of tables, a value was provided as null or empty string.", "tableNames");
                        dataAdapter.TableMappings.Add(tableName, tableNames[index]);
                        tableName += (index + 1).ToString();
                    }
                }
                // Fill the DataSet using default values for DataTable names, etc
                dataAdapter.Fill(dataSet);
                // Detach the OleDbParameters from the command object, so they can be used again
                command.Parameters.Clear();
            }
            if (mustCloseConnection)
                connection.Close();
        }
        #endregion
        #region UpdateDataset
       
        public static void UpdateDataset(OleDbCommand insertCommand, OleDbCommand deleteCommand, OleDbCommand updateCommand, DataSet dataSet, string tableName)
        {
            if (insertCommand == null) throw new ArgumentNullException("insertCommand");
            if (deleteCommand == null) throw new ArgumentNullException("deleteCommand");
            if (updateCommand == null) throw new ArgumentNullException("updateCommand");
            if (tableName == null || tableName.Length == 0) throw new ArgumentNullException("tableName");
            // Create a OleDbDataAdapter, and dispose of it after we are done
            using (OleDbDataAdapter dataAdapter = new OleDbDataAdapter())
            {
                // Set the data adapter commands
                dataAdapter.UpdateCommand = updateCommand;
                dataAdapter.InsertCommand = insertCommand;
                dataAdapter.DeleteCommand = deleteCommand;
                // Update the dataset changes in the data source
                dataAdapter.Update(dataSet, tableName);
                // Commit all the changes made to the DataSet
                dataSet.AcceptChanges();
            }
        }
        #endregion
        #region CreateCommand
       
        public static OleDbCommand CreateCommand(OleDbConnection connection, string spName, params string[] sourceColumns)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // Create a OleDbCommand
            OleDbCommand cmd = new OleDbCommand(spName, connection);
            cmd.CommandType = CommandType.StoredProcedure;
            // If we receive parameter values, we need to figure out where they go
            if ((sourceColumns != null) && (sourceColumns.Length > 0))
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Assign the provided source columns to these parameters based on parameter order
                for (int index = 0; index < sourceColumns.Length; index++)
                    commandParameters[index].SourceColumn = sourceColumns[index];
                // Attach the discovered parameters to the OleDbCommand object
                AttachParameters(cmd, commandParameters);
            }
            return cmd;
        }
        #endregion
        #region ExecuteNonQueryTypedParams
       
        public static int ExecuteNonQueryTypedParams(String connectionString, String spName, DataRow dataRow)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
            }
        }
       
        public static int ExecuteNonQueryTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
            }
        }
     
        public static int ExecuteNonQueryTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // Sf the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion
        #region ExecuteDatasetTypedParams
      
        public static DataSet ExecuteDatasetTypedParams(string connectionString, String spName, DataRow dataRow)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            //If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
            }
        }
       
        public static DataSet ExecuteDatasetTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName);
            }
        }
       
        public static DataSet ExecuteDatasetTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion
        #region ExecuteReaderTypedParams
       
        public static OleDbDataReader ExecuteReaderTypedParams(String connectionString, String spName, DataRow dataRow)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
            }
        }
      
        public static OleDbDataReader ExecuteReaderTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName);
            }
        }
      
        public static OleDbDataReader ExecuteReaderTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion
        #region ExecuteScalarTypedParams
       
        public static object ExecuteScalarTypedParams(String connectionString, String spName, DataRow dataRow)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connectionString, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
            }
        }
      
        public static object ExecuteScalarTypedParams(OleDbConnection connection, String spName, DataRow dataRow)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName);
            }
        }
     
        public static object ExecuteScalarTypedParams(OleDbTransaction transaction, String spName, DataRow dataRow)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
                OleDbParameter[] commandParameters = OleDbHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
                // Set the parameters values
                AssignParameterValues(commandParameters, dataRow);
                return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            else
            {
                return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
            }
        }
        #endregion
      
    }
    
    public sealed class OleDbHelperParameterCache
    {
        #region private methods, variables, and constructors
        //Since this class provides only static methods, make the default constructor private to prevent 
        //instances from being created with "new OleDbHelperParameterCache()"
        private OleDbHelperParameterCache() { }
        private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
       
        private static OleDbParameter[] DiscoverSpParameterSet(OleDbConnection connection, string spName, bool includeReturnValueParameter)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            OleDbCommand cmd = new OleDbCommand(spName, connection);
            cmd.CommandType = CommandType.StoredProcedure;
            connection.Open();
            OleDbCommandBuilder.DeriveParameters(cmd);
            connection.Close();
            if (!includeReturnValueParameter)
            {
                cmd.Parameters.RemoveAt(0);
            }
            OleDbParameter[] discoveredParameters = new OleDbParameter[cmd.Parameters.Count];
            cmd.Parameters.CopyTo(discoveredParameters, 0);
            // Init the parameters with a DBNull value
            foreach (OleDbParameter discoveredParameter in discoveredParameters)
            {
                discoveredParameter.Value = DBNull.Value;
            }
            return discoveredParameters;
        }
       
        private static OleDbParameter[] CloneParameters(OleDbParameter[] originalParameters)
        {
            OleDbParameter[] clonedParameters = new OleDbParameter[originalParameters.Length];
            for (int i = 0, j = originalParameters.Length; i < j; i++)
            {
                clonedParameters[i] = (OleDbParameter)((ICloneable)originalParameters[i]).Clone();
            }
            return clonedParameters;
        }
        #endregion private methods, variables, and constructors
        #region caching functions
       
        public static void CacheParameterSet(string connectionString, string commandText, params OleDbParameter[] commandParameters)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");
            string hashKey = connectionString + ":" + commandText;
            paramCache[hashKey] = commandParameters;
        }
       
        public static OleDbParameter[] GetCachedParameterSet(string connectionString, string commandText)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");
            string hashKey = connectionString + ":" + commandText;
            OleDbParameter[] cachedParameters = paramCache[hashKey] as OleDbParameter[];
            if (cachedParameters == null)
            {
                return null;
            }
            else
            {
                return CloneParameters(cachedParameters);
            }
        }
        #endregion caching functions
        #region Parameter Discovery Functions
       
        public static OleDbParameter[] GetSpParameterSet(string connectionString, string spName)
        {
            return GetSpParameterSet(connectionString, spName, false);
        }
       
        public static OleDbParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
        {
            if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                return GetSpParameterSetInternal(connection, spName, includeReturnValueParameter);
            }
        }
       
        internal static OleDbParameter[] GetSpParameterSet(OleDbConnection connection, string spName)
        {
            return GetSpParameterSet(connection, spName, false);
        }
       
        internal static OleDbParameter[] GetSpParameterSet(OleDbConnection connection, string spName, bool includeReturnValueParameter)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            using (OleDbConnection clonedConnection = (OleDbConnection)((ICloneable)connection).Clone())
            {
                return GetSpParameterSetInternal(clonedConnection, spName, includeReturnValueParameter);
            }
        }
      
        private static OleDbParameter[] GetSpParameterSetInternal(OleDbConnection connection, string spName, bool includeReturnValueParameter)
        {
            if (connection == null) throw new ArgumentNullException("connection");
            if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
            string hashKey = connection.ConnectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter" : "");
            OleDbParameter[] cachedParameters;
            cachedParameters = paramCache[hashKey] as OleDbParameter[];
            if (cachedParameters == null)
            {
                OleDbParameter[] spParameters = DiscoverSpParameterSet(connection, spName, includeReturnValueParameter);
                paramCache[hashKey] = spParameters;
                cachedParameters = spParameters;
            }
            return CloneParameters(cachedParameters);
        }
        #endregion Parameter Discovery Functions
    }
}

posted on 2009-11-05 16:12  风乔  阅读(228)  评论(0编辑  收藏  举报

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