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 h

using System;

using System.Data;

using System.Xml;

using System.Data.OleDb;

using System.Collections;

using System.Configuration;

namespace Microsoft.ApplicationBlocks.Data

{

///

/// The SqlHelper class is intended to encapsulate high performance, scalable best practices for

/// common uses of OleDbClient

///

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

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

{

// 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

{

///

Connection is owned and managed by SqlHelper

Internal,

///

Connection is owned and managed by the caller

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, commandParamet