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  • 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
        }
    }
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  • 原文地址:https://www.cnblogs.com/zzxap/p/2175584.html
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