SQL Helper Class.

Sql healper Class :



This is a class of all common function and  methods of sql that are required in database programming in ASSP .NET Methods including Execute Scaler ,Adapter,datset,sqlcommend, Execute Table and methods related to Prepared statments.


using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;
//===============================================================================
// Microsoft Data Access Application Block for .NET
=======

using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;


namespace DBLibrary
{
    /// <summary>
    /// The SqlHelper class is intended to encapsulate high performance, scalable best practices for
    /// common uses of SqlClient.
    /// </summary>
    public sealed class SqlHelper
    {

        #region private utility methods & constructors

        //Since this class provides only static methods, make the default constructor private to prevent
        //instances from being created with "new SqlHelper()".
        private SqlHelper() { }



        /// <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 tho be added to command</param>
        private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
        {
            foreach (SqlParameter p in commandParameters)
            {
                //check for derived output value with no value assigned
                if ((p.Direction == ParameterDirection.InputOutput) && (p.Value == null))
                {
                    p.Value = DBNull.Value;
                }

                command.Parameters.Add(p);
            }
        }

        /// <summary>
        /// This method assigns an array of values to an array of 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++)
            {
                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>
        private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters)
        {
            //if the provided connection is not open, we will open it
            if (connection.State != ConnectionState.Open)
            {
                connection.Open();
            }

            //associate the connection with the command
            command.Connection = connection;

            //set the command text (stored procedure name or SQL statement)
            command.CommandText = commandText;

            //if we were provided a transaction, assign it.
            if (transaction != null)
            {
                command.Transaction = transaction;
            }

            //set the command type
            command.CommandType = commandType;

            //attach the command parameters if they are provided
            if (commandParameters != null)
            {
                AttachParameters(command, commandParameters);
            }

            return;
        }


        #endregion private utility methods & constructors

        #region ExecuteNonQuery

        /// <summary>
        /// Execute 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)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                try
                {
                    cn.Open();

                    //call the overload that takes a connection in place of the connection string
                    return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
                }
                finally
                {
                    cn.Dispose();
                }
            }
        }

        /// <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 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);
            }
            //otherwise we can just call the SP without params
            else
            {
                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)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //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 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 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.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(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                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)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

            //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 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.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(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
            }
        }


        #endregion ExecuteNonQuery

        #region ExecuteDataSet

        /// <summary>
        /// Execute 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)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                try
                {
                    cn.Open();

                    //call the overload that takes a connection in place of the connection string
                    return ExecuteDataset(cn, commandType, commandText, commandParameters);
                }
                finally
                {
                    cn.Dispose();
                }

            }
        }

        /// <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 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);
            }
            //otherwise we can just call the SP without params
            else
            {
                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)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            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
            connection.Close();
            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 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.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(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                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)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            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 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.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(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
            }
        }

        #endregion ExecuteDataSet

        #region ExecuteReader

        /// <summary>
        /// this enum is used to indicate 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
        }

        /// <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)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);

            //create a reader
            SqlDataReader dr;

            // call ExecuteReader with the appropriate CommandBehavior
            if (connectionOwnership == SqlConnectionOwnership.External)
            {
                dr = cmd.ExecuteReader();
            }
            else
            {
                dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();

            return dr;
        }

        /// <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)
        {
            //create & open a SqlConnection
            SqlConnection cn = new SqlConnection(connectionString);
            cn.Open();

            try
            {
                //call the private overload that takes an internally owned connection in place of the connection string
                return ExecuteReader(cn, null, commandType, commandText, commandParameters, SqlConnectionOwnership.Internal);
            }
            catch (Exception ex)
            {
                //DBLayer.DBLInstance.GlobalInstance.ExceptionAndEventHandling(ex);
                //if we fail to return the SqlDatReader, we need to close the connection ourselves
                cn.Close();
                throw ex;
            }



        }

        /// <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 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 ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                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 we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);

                AssignParameterValues(commandParameters, parameterValues);

                return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteReader(connection, CommandType.StoredProcedure, spName);
            }
        }

        /// <summary>
        /// Execute 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)
        {
            //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 we receive parameter values, we need to figure out where they go
            if ((parameterValues != null) && (parameterValues.Length > 0))
            {
                SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);

                AssignParameterValues(commandParameters, parameterValues);

                return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
            }
        }


        #endregion ExecuteReader

        #region ExecuteScalar

        /// <summary>
        /// Execute 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)
        {
            //create & open a SqlConnection, and dispose of it after we are done.
            using (SqlConnection cn = new SqlConnection(connectionString))
            {
                cn.Open();

                //call the overload that takes a connection in place of the connection string
                return ExecuteScalar(cn, commandType, commandText, commandParameters);

            }
        }

        /// <summary>
        /// Execute a stored procedure via 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 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 ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
        /// </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 object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", 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 object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //execute the command & return the results
            object retval = cmd.ExecuteScalar();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            connection.Close();

            return retval;

        }

        /// <summary>
        /// Execute a stored procedure via a SqlCommand (that returns a 1x1 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 orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 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 object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlConnection connection, string spName, params object[] parameterValues)
        {
            //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.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 ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
        /// </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 object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", 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 object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

            //execute the command & return the results
            object retval = cmd.ExecuteScalar();

            // detach the SqlParameters from the command object, so they can be used again.
            cmd.Parameters.Clear();
            transaction.Connection.Close();
            return retval;
        }

        /// <summary>
        /// Execute a stored procedure via a SqlCommand (that returns a 1x1 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 orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 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 object containing the value in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(SqlTransaction transaction, string spName, params object[] parameterValues)
        {
            //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.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 ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
            }
        }

        #endregion ExecuteScalar

        #region ExecuteXmlReader

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlConnection.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  XmlReader r = ExecuteXmlReader(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 using "FOR XML AUTO"</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteXmlReader(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.:
        ///  XmlReader r = ExecuteXmlReader(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 using "FOR XML AUTO"</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            XmlReader retval = cmd.ExecuteXmlReader();

            // 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 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.:
        ///  XmlReader r = ExecuteXmlReader(conn, "GetOrders", 24, 36);
        /// </remarks>
        /// <param name="connection">a valid SqlConnection</param>
        /// <param name="spName">the name of the stored procedure using "FOR XML AUTO"</param>
        /// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlConnection connection, string spName, params object[] parameterValues)
        {
            //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.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 ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns a resultset and takes no parameters) against the provided SqlTransaction.
        /// </summary>
        /// <remarks>
        /// e.g.:
        ///  XmlReader r = ExecuteXmlReader(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 using "FOR XML AUTO"</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of SqlParameters
            return ExecuteXmlReader(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.:
        ///  XmlReader r = ExecuteXmlReader(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 using "FOR XML AUTO"</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an XmlReader containing the resultset generated by the command</returns>
        public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            XmlReader retval = cmd.ExecuteXmlReader();

            // 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 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.:
        ///  XmlReader r = ExecuteXmlReader(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 XmlReader ExecuteXmlReader(SqlTransaction transaction, string spName, params object[] parameterValues)
        {
            //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.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 ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
            }
            //otherwise we can just call the SP without params
            else
            {
                return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
            }
        }


        #endregion ExecuteXmlReader
    }

    /// <summary>
    /// SqlHelperParameterCache provides functions to leverage a static cache of procedure parameters, and the
    /// ability to discover parameters for stored procedures at run-time.
    /// </summary>
    public sealed class SqlHelperParameterCache
    {
        #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 SqlHelperParameterCache()".
        private SqlHelperParameterCache() { }

        private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());

        /// <summary>
        /// resolve at run time the appropriate set of SqlParameters for a stored procedure
        /// </summary>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="spName">the name of the stored procedure</param>
        /// <param name="includeReturnValueParameter">whether or not to include their return value parameter</param>
        /// <returns></returns>
        private static SqlParameter[] DiscoverSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
        {
            using (SqlConnection cn = new SqlConnection(connectionString))
            using (SqlCommand cmd = new SqlCommand(spName, cn))
            {
                cn.Open();
                cmd.CommandType = CommandType.StoredProcedure;

                SqlCommandBuilder.DeriveParameters(cmd);

                if (!includeReturnValueParameter)
                {
                    cmd.Parameters.RemoveAt(0);
                }

                SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count]; ;

                cmd.Parameters.CopyTo(discoveredParameters, 0);
                cn.Close();

                return discoveredParameters;
            }
        }

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

            for (int i = 0, j = originalParameters.Length; i < j; i++)
            {
                clonedParameters[i] = (SqlParameter)((ICloneable)originalParameters[i]).Clone();
            }

            return clonedParameters;
        }

        #endregion private methods, variables, and constructors

        #region caching functions

        /// <summary>
        /// add parameter array to the cache
        /// </summary>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters to be cached</param>
        public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
        {
            string hashKey = connectionString + ":" + commandText;

            paramCache[hashKey] = commandParameters;
        }

        /// <summary>
        /// retrieve a parameter array from the cache
        /// </summary>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <returns>an array of SqlParamters</returns>
        public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
        {
            string hashKey = connectionString + ":" + commandText;

            SqlParameter[] cachedParameters = (SqlParameter[])paramCache[hashKey];

            if (cachedParameters == null)
            {
                return null;
            }
            else
            {
                return CloneParameters(cachedParameters);
            }
        }

        #endregion caching functions

        #region Parameter Discovery Functions

        /// <summary>
        /// Retrieves the set of SqlParameters appropriate for the stored procedure
        /// </summary>
        /// <remarks>
        /// This method will query the database for this information, and then store it in a cache for future requests.
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="spName">the name of the stored procedure</param>
        /// <returns>an array of SqlParameters</returns>
        public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
        {
            return GetSpParameterSet(connectionString, spName, false);
        }

        /// <summary>
        /// Retrieves the set of SqlParameters appropriate for the stored procedure
        /// </summary>
        /// <remarks>
        /// This method will query the database for this information, and then store it in a cache for future requests.
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="spName">the name of the stored procedure</param>
        /// <param name="includeReturnValueParameter">a bool value indicating whether the return value parameter should be included in the results</param>
        /// <returns>an array of SqlParameters</returns>
        public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
        {
            string hashKey = connectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter" : "");

            SqlParameter[] cachedParameters;

            cachedParameters = (SqlParameter[])paramCache[hashKey];

            if (cachedParameters == null)
            {
                cachedParameters = (SqlParameter[])(paramCache[hashKey] = DiscoverSpParameterSet(connectionString, spName, includeReturnValueParameter));
            }

            return CloneParameters(cachedParameters);
        }

        #endregion Parameter Discovery Functions

    }
}

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