微软官方SqlHelper类数据库辅助操作类

本文就为大家介绍微软官方的程序PetShop4.0中的SqlHelper类，先来做一下简单的介绍，PetShop是一个范例，微软用它来展示.Net企业系统开发的能力。

那SqlHelper中封装了哪些方法呢？

里面的函数一堆，常用的就那几个，无非就是增删改查嘛，来看下几种常用的函数：

1.ExecuteNonQuery 执行增删改
2.ExecuteReader 执行查询
3.ExecuteScalar 返回首行首列

使用方法介绍

Web.config配置

<connectionStrings>
    <add name="ConnectionString" connectionString="server=127.0.0.1;uid=sa;pwd=ok;database=PetShop;Max Pool Size =512; Min Pool Size=0; Connection Lifetime = 300;packet size=1000;" providerName="System.Data.SqlClient" />
</connectionStrings>

调用函数的写法

sql = "UPDATE Student set Name = @Name WHERE Id = @Id";
SqlHelper.ExecuteNonQuery(CommandType.Text, sql, new SqlParameter[]{
 new SqlParameter("@Name", name),
 new SqlParameter("@Id", id)
});

这样调用就比较简化，而且比较灵活

源码呈上

/// <summary>
  /// The SqlHelper class is intended to encapsulate high performance, 
  /// scalable best practices for common uses of SqlClient.
  /// </summary>
  public abstract class SqlHelper
  {
 
    //数据库连接字符串
    public static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["SQLConnString"].ConnectionString;
 
    #region 私有函数和方法
 
    /// <summary>
    /// This method is used to attach array of SqlParameters to a SqlCommand.
    /// 
    /// This method will assign a value of DbNull to any parameter with a direction of
    /// InputOutput and a value of null. 
    /// 
    /// This behavior will prevent default values from being used, but
    /// this will be the less common case than an intended pure output parameter (derived as InputOutput)
    /// where the user provided no input value.
    /// </summary>
    /// <param name="command">The command to which the parameters will be added</param>
    /// <param name="commandParameters">An array of SqlParameters to be added to command</param>
    private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
    {
      if (command == null) throw new ArgumentNullException("command");
      if (commandParameters != null)
      {
        foreach (SqlParameter 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);
          }
        }
      }
    }
 
    /// <summary>
    /// This method assigns dataRow column values to an array of SqlParameters
    /// </summary>
    /// <param name="commandParameters">Array of SqlParameters to be assigned values</param>
    /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values</param>
    private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow)
    {
      if ((commandParameters == null) || (dataRow == null))
      {
        // Do nothing if we get no data
        return;
      }
 
      int i = 0;
      // Set the parameters values
      foreach (SqlParameter 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++;
      }
    }
 
    /// <summary>
    /// This method assigns an array of values to an array of SqlParameters
    /// </summary>
    /// <param name="commandParameters">Array of SqlParameters to be assigned values</param>
    /// <param name="parameterValues">Array of objects holding the values to be assigned</param>
    private static void AssignParameterValues(SqlParameter[] 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 SqlParameters, 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];
        }
      }
    }
 
    /// <summary>
    /// This method opens (if necessary) and assigns a connection, transaction, command type and parameters 
    /// to the provided command
    /// </summary>
    /// <param name="command">The SqlCommand to be prepared</param>
    /// <param name="connection">A valid SqlConnection, on which to execute this command</param>
    /// <param name="transaction">A valid SqlTransaction, or 'null'</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
    /// <param name="mustCloseConnection"><c>true</c> if the connection was opened by the method, otherwose is false.</param>
    private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] 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 SQL 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(CommandType cmdType, string cmdText)
    {
      return ExecuteNonQuery(ConnectionString, cmdType, cmdText);
    }
 
    public static int ExecuteNonQuery(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
    {
      return ExecuteNonQuery(ConnectionString, cmdType, cmdText, commandParameters);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the database specified in 
    /// the connection string
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string 
    /// using the provided parameters
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
 
      // Create & open a SqlConnection, and dispose of it after we are done
      using (SqlConnection connection = new SqlConnection(connectionString))
      {
        connection.Open();
 
        // Call the overload that takes a connection in place of the connection string
        return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
      }
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns no resultset) against the database specified in 
    /// the connection string using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="spName">The name of the stored prcedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
    {
      if (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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
        return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
      }
      else
      {
        // Otherwise we can just call the SP without params
        return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlConnection. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns no resultset) against the specified SqlConnection 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      if (connection == null) throw new ArgumentNullException("connection");
 
      // Create a command and prepare it for execution
      SqlCommand cmd = new SqlCommand();
      bool mustCloseConnection = false;
      PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
 
      // Finally, execute the command
      int retval = cmd.ExecuteNonQuery();
 
      // Detach the SqlParameters from the command object, so they can be used again
      cmd.Parameters.Clear();
      if (mustCloseConnection)
        connection.Close();
      return retval;
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns no resultset) against the specified SqlConnection 
    /// using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(SqlConnection 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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
        return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
      }
      else
      {
        // Otherwise we can just call the SP without params
        return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns no resultset and takes no parameters) against the provided SqlTransaction. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns no resultset) against the specified SqlTransaction
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] 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
      SqlCommand cmd = new SqlCommand();
      bool mustCloseConnection = false;
      PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
      // Finally, execute the command
      int retval = cmd.ExecuteNonQuery();
 
      // Detach the SqlParameters from the command object, so they can be used again
      cmd.Parameters.Clear();
      return retval;
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns no resultset) against the specified 
    /// SqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>An int representing the number of rows affected by the command</returns>
    public static int ExecuteNonQuery(SqlTransaction 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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
        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(CommandType commandType, string commandText)
    {
      return ExecuteDataset(ConnectionString, commandType, commandText);
    }
 
    public static DataSet ExecuteDataset(CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      return ExecuteDataset(ConnectionString, commandType, commandText, commandParameters);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
    /// the connection string. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
 
      // Create & open a SqlConnection, and dispose of it after we are done
      using (SqlConnection connection = new SqlConnection(connectionString))
      {
        connection.Open();
 
        // Call the overload that takes a connection in place of the connection string
        return ExecuteDataset(connection, commandType, commandText, commandParameters);
      }
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the database specified in 
    /// the connection string using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
    {
      if (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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
        return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
      }
      else
      {
        // Otherwise we can just call the SP without params
        return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      if (connection == null) throw new ArgumentNullException("connection");
 
      // Create a command and prepare it for execution
      SqlCommand cmd = new SqlCommand();
      bool mustCloseConnection = false;
      PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
 
      // Create the DataAdapter & DataSet
      using (SqlDataAdapter da = new SqlDataAdapter(cmd))
      {
        DataSet ds = new DataSet();
 
        // Fill the DataSet using default values for DataTable names, etc
        da.Fill(ds);
 
        // Detach the SqlParameters from the command object, so they can be used again
        cmd.Parameters.Clear();
 
        if (mustCloseConnection)
          connection.Close();
 
        // Return the dataset
        return ds;
      }
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified SqlConnection 
    /// using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(SqlConnection 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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
        return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
      }
      else
      {
        // Otherwise we can just call the SP without params
        return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] 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
      SqlCommand cmd = new SqlCommand();
      bool mustCloseConnection = false;
      PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
      // Create the DataAdapter & DataSet
      using (SqlDataAdapter da = new SqlDataAdapter(cmd))
      {
        DataSet ds = new DataSet();
 
        // Fill the DataSet using default values for DataTable names, etc
        da.Fill(ds);
 
        // Detach the SqlParameters from the command object, so they can be used again
        cmd.Parameters.Clear();
 
        // Return the dataset
        return ds;
      }
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified 
    /// SqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>A dataset containing the resultset generated by the command</returns>
    public static DataSet ExecuteDataset(SqlTransaction 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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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 SqlParameters
        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
 
    /// <summary>
    /// This enum is used to indicate whether the connection was provided by the caller, or created by SqlHelper, so that
    /// we can set the appropriate CommandBehavior when calling ExecuteReader()
    /// </summary>
    private enum SqlConnectionOwnership
    {
      /// <summary>Connection is owned and managed by SqlHelper</summary>
      Internal,
      /// <summary>Connection is owned and managed by the caller</summary>
      External
    }
 
    public static SqlDataReader ExecuteReader(CommandType cmdType, string cmdText)
    {
      return ExecuteReader(ConnectionString, cmdType, cmdText);
    }
 
    public static SqlDataReader ExecuteReader(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
    {
      return ExecuteReader(ConnectionString, cmdType, cmdText, commandParameters);
    }
 
    /// <summary>
    /// Create and prepare a SqlCommand, and call ExecuteReader with the appropriate CommandBehavior.
    /// </summary>
    /// <remarks>
    /// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
    /// 
    /// If the caller provided the connection, we want to leave it to them to manage.
    /// </remarks>
    /// <param name="connection">A valid SqlConnection, on which to execute this command</param>
    /// <param name="transaction">A valid SqlTransaction, or 'null'</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParameters to be associated with the command or 'null' if no parameters are required</param>
    /// <param name="connectionOwnership">Indicates whether the connection parameter was provided by the caller, or created by SqlHelper</param>
    /// <returns>SqlDataReader containing the results of the command</returns>
    private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
    {
      if (connection == null) throw new ArgumentNullException("connection");
 
      bool mustCloseConnection = false;
      // Create a command and prepare it for execution
      SqlCommand cmd = new SqlCommand();
      try
      {
        PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
        // Create a reader
        SqlDataReader dataReader;
 
        // Call ExecuteReader with the appropriate CommandBehavior
        if (connectionOwnership == SqlConnectionOwnership.External)
        {
          dataReader = cmd.ExecuteReader();
        }
        else
        {
          dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
 
        // Detach the SqlParameters 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 SqlReader can磘 set its values. 
        // When this happen, the parameters can磘 be used again in other command.
        bool canClear = true;
        foreach (SqlParameter commandParameter in cmd.Parameters)
        {
          if (commandParameter.Direction != ParameterDirection.Input)
            canClear = false;
        }
 
        if (canClear)
        {
          cmd.Parameters.Clear();
        }
 
        return dataReader;
      }
      catch
      {
        if (mustCloseConnection)
          connection.Close();
        throw;
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the database specified in 
    /// the connection string. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset) against the database specified in the connection string 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
      SqlConnection connection = null;
      try
      {
        connection = new SqlConnection(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, SqlConnectionOwnership.Internal);
      }
      catch
      {
        // If we fail to return the SqlDatReader, we need to close the connection ourselves
        if (connection != null) connection.Close();
        throw;
      }
 
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the database specified in 
    /// the connection string using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader 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))
      {
        SqlParameter[] commandParameters = SqlHelperParameterCache.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);
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      // Pass through the call to the private overload using a null transaction value and an externally owned connection
      return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified SqlConnection 
    /// using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
    /// </remarks>
    /// <param name="connection">A valid SqlConnection</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(SqlConnection 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))
      {
        SqlParameter[] commandParameters = SqlHelperParameterCache.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);
      }
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a resultset) against the specified SqlTransaction
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] 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, SqlConnectionOwnership.External);
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the specified
    /// SqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// SqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
    /// </remarks>
    /// <param name="transaction">A valid SqlTransaction</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>A SqlDataReader containing the resultset generated by the command</returns>
    public static SqlDataReader ExecuteReader(SqlTransaction 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))
      {
        SqlParameter[] commandParameters = SqlHelperParameterCache.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(CommandType cmdType, string cmdText)
    {
      return ExecuteScalar(ConnectionString, cmdType, cmdText);
    }
 
    public static object ExecuteScalar(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
    {
      return ExecuteScalar(ConnectionString, cmdType, cmdText, commandParameters);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the database specified in 
    /// the connection string. 
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
    public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
    {
      // Pass through the call providing null for the set of SqlParameters
      return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
    }
 
    /// <summary>
    /// Execute a SqlCommand (that returns a 1x1 resultset) against the database specified in the connection string 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.: 
    /// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
    /// <param name="commandText">The stored procedure name or T-SQL command</param>
    /// <param name="commandParameters">An array of SqlParamters used to execute the command</param>
    /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
    public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
      if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
      // Create & open a SqlConnection, and dispose of it after we are done
      using (SqlConnection connection = new SqlConnection(connectionString))
      {
        connection.Open();
 
        // Call the overload that takes a connection in place of the connection string
        return ExecuteScalar(connection, commandType, commandText, commandParameters);
      }
    }
 
    /// <summary>
    /// Execute a stored procedure via a SqlCommand (that returns a 1x1 resultset) against the database specified in 
    /// the connection string using the provided parameter values. This method will query the database to discover the parameters for the 
    /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
    /// </summary>
    /// <remarks>
    /// This method provides no access to output parameters or the stored procedure's return value parameter.
    /// 
    /// e.g.: 
    /// int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
    /// </remarks>
    /// <param name="connectionString">A valid connection string for a SqlConnection</param>
    /// <param name="spName">The name of the stored procedure</param>
    /// <param name="parameterValues">An array of objects to be assigned as the input values of the stored procedure</param>
    /// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
    public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
    {
      if (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)
        SqlParameter[] commandParameters = SqlHelperParameterCache.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