ECS / WCS_LiuzhouZhituo · Files

using System;
using System.Configuration;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;
using MySql.Data.MySqlClient;

namespace HHWCS.DB
{
    /// <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 MySqlParameters to a MySqlCommand.
        /// 
        /// 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 MySqlParameters tho be added to command</param>
        private static void AttachParameters(MySqlCommand command, MySqlParameter[] commandParameters)
        {
            foreach (MySqlParameter 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 MySqlParameters.
        /// </summary>
        /// <param name="commandParameters">array of MySqlParameters to be assigned values</param>
        /// <param name="parameterValues">array of Components holding the values to be assigned</param>
        private static void AssignParameterValues(MySqlParameter[] 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("参数与值数量不匹配.");
            }

            //iterate through the MySqlParameters, 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 MySqlCommand to be prepared</param>
        /// <param name="connection">a valid MySqlConnection, on which to execute this command</param>
        /// <param name="transaction">a valid MySqlTransaction, 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 MySqlParameters to be associated with the command or 'null' if no parameters are required</param>
        /// 
        private static void PrepareCommand(MySqlCommand command, MySqlConnection connection, MySqlTransaction transaction, CommandType commandType, string commandText, MySqlParameter[] 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 DataHelpers

        public static string CheckNull(object obj)
        {
            return (string)obj;
        }

        public static string CheckNull(DBNull obj)
        {
            return null;
        }

        #endregion

        #region AddParameters

        public static object CheckForNullString(string text)
        {
            if (text == null || text.Trim().Length == 0)
            {
                return System.DBNull.Value;
            }
            else
            {
                return text;
            }
        }

        public static MySqlParameter MakeInParam(string ParamName, object Value)
        {
            return new MySqlParameter(ParamName, Value);
        }

        /// <summary>
        /// Make input param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <param name="Value">Param value.</param>
        /// <returns>New parameter.</returns>
        public static MySqlParameter MakeInParam(string ParamName, SqlDbType DbType, int Size, object Value)
        {
            return MakeParam(ParamName, DbType, Size, ParameterDirection.Input, Value);
        }

        /// <summary>
        /// Make input param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <returns>New parameter.</returns>
        public static MySqlParameter MakeOutParam(string ParamName, SqlDbType DbType, int Size)
        {
            return MakeParam(ParamName, DbType, Size, ParameterDirection.Output, null);
        }

        /// <summary>
        /// Make stored procedure param.
        /// </summary>
        /// <param name="ParamName">Name of param.</param>
        /// <param name="DbType">Param type.</param>
        /// <param name="Size">Param size.</param>
        /// <param name="Direction">Parm direction.</param>
        /// <param name="Value">Param value.</param>
        /// <returns>New parameter.</returns>
        public static MySqlParameter MakeParam(string ParamName, SqlDbType DbType, Int32 Size, ParameterDirection Direction, object Value)
        {
            MySqlParameter param;

            if (Size > 0)
                param = new MySqlParameter(ParamName, (MySqlDbType)DbType, Size);
            else
                param = new MySqlParameter(ParamName, DbType);

            param.Direction = Direction;
            if (!(Direction == ParameterDirection.Output && Value == null))
                param.Value = Value;

            return param;
        }


        #endregion

        #region ExecuteNonQuery

        /// <summary>
        /// Execute a MySqlCommand (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 MySqlConnection</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 MySqlParameters
            return ExecuteNonQuery(connectionString, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (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 MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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 MySqlParameter[] commandParameters)
        {
            //create & open a MySqlConnection, and dispose of it after we are done.
            using (MySqlConnection cn = new MySqlConnection(connectionString))
            {
                cn.Open();

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

        /// <summary>
        /// Execute a MySqlCommand (that returns no resultset and takes no parameters) against the provided MySqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteNonQuery(connection, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns no resultset) against the specified MySqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, connection, (MySqlTransaction)null, commandType, commandText, commandParameters);

            //finally, execute the command.
            int retval = cmd.ExecuteNonQuery();

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


        /// <summary>
        /// Execute a MySqlCommand (that returns no resultset and takes no parameters) against the provided MySqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteNonQuery(transaction, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns no resultset) against the specified MySqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, (MySqlConnection)transaction.Connection, transaction, commandType, commandText, commandParameters);
            //finally, execute the command.
            int retval = cmd.ExecuteNonQuery();

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




        #endregion ExecuteNonQuery

        #region ExecuteDataSet

        /// <summary>
        /// Execute a MySqlCommand (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 MySqlConnection</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 MySqlParameters
            return ExecuteDataset(connectionString, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (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 MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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 MySqlParameter[] commandParameters)
        {
            //create & open a MySqlConnection, and dispose of it after we are done.
            using (MySqlConnection cn = new MySqlConnection(connectionString))
            {
                cn.Open();

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



        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteDataset(connection, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, connection, (MySqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            MySqlDataAdapter da = new MySqlDataAdapter(cmd);
            DataSet ds = new DataSet();

            //fill the DataSet using default values for DataTable names, etc.
            da.Fill(ds);

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

            //return the dataset
            return ds;
        }


        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteDataset(transaction, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, (MySqlConnection)transaction.Connection, transaction, commandType, commandText, commandParameters);

            //create the DataAdapter & DataSet
            MySqlDataAdapter da = new MySqlDataAdapter(cmd);
            DataSet ds = new DataSet();

            //fill the DataSet using default values for DataTable names, etc.
            da.Fill(ds);

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

            //return the dataset
            return ds;
        }



        #endregion ExecuteDataSet

        #region ExecuteDataTable

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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 DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteDataTable(connectionString, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(connString, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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 DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create & open a MySqlConnection, and dispose of it after we are done.
            using (MySqlConnection cn = new MySqlConnection(connectionString))
            {
                cn.Open();

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



        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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 DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(MySqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteDataTable(connection, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(conn, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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 DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(MySqlConnection connection, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, connection, (MySqlTransaction)null, commandType, commandText, commandParameters);

            //create the DataAdapter & DataTable
            MySqlDataAdapter da = new MySqlDataAdapter(cmd);
            DataTable dt = new DataTable();

            //fill the DataTable using default values for DataTable names, etc.
            da.Fill(dt);

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

            //return the DataTable
            return dt;
        }


        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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 DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(MySqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteDataTable(transaction, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  DataTable dt = ExecuteDataTable(trans, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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 DataTable containing the resultset generated by the command</returns>
        public static DataTable ExecuteDataTable(MySqlTransaction transaction, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, (MySqlConnection)transaction.Connection, transaction, commandType, commandText, commandParameters);

            //create the DataAdapter & DataTable
            MySqlDataAdapter da = new MySqlDataAdapter(cmd);
            DataTable dt = new DataTable();

            //fill the DataTable using default values for DataTable names, etc.
            da.Fill(dt);

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

            //return the DataTable
            return dt;
        }



        #endregion ExecuteDataTable

        #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 MySqlConnectionOwnership
        {
            /// <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 MySqlCommand, 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 MySqlConnection, on which to execute this command</param>
        /// <param name="transaction">a valid MySqlTransaction, 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 MySqlParameters 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> MySqlDataReader containing the results of the command</returns>
        private static MySqlDataReader ExecuteReader(MySqlConnection connection, MySqlTransaction transaction, CommandType commandType, string commandText, MySqlParameter[] commandParameters, MySqlConnectionOwnership connectionOwnership)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);

            //create a reader
            MySqlDataReader dr;

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

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

            return dr;
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the database specified in 
        /// the connection string. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///   MySqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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  MySqlDataReader containing the resultset generated by the command</returns>
        public static MySqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteReader(connectionString, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///   MySqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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  MySqlDataReader containing the resultset generated by the command</returns>
        public static MySqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create & open a MySqlConnection
            MySqlConnection cn = new MySqlConnection(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, MySqlConnectionOwnership.Internal);
            }
            catch
            {
                //if we fail to return the SqlDatReader, we need to close the connection ourselves
                cn.Close();
                throw;
            }
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///   MySqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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  MySqlDataReader containing the resultset generated by the command</returns>
        public static MySqlDataReader ExecuteReader(MySqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteReader(connection, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///   MySqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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  MySqlDataReader containing the resultset generated by the command</returns>
        public static MySqlDataReader ExecuteReader(MySqlConnection connection, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //pass through the call to the private overload using a null transaction value and an externally owned connection
            return ExecuteReader(connection, (MySqlTransaction)null, commandType, commandText, commandParameters, MySqlConnectionOwnership.External);
        }


        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///   MySqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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  MySqlDataReader containing the resultset generated by the command</returns>
        public static MySqlDataReader ExecuteReader(MySqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteReader(transaction, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///    MySqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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  MySqlDataReader containing the resultset generated by the command</returns>
        public static MySqlDataReader ExecuteReader(MySqlTransaction transaction, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //pass through to private overload, indicating that the connection is owned by the caller
            return ExecuteReader((MySqlConnection)transaction.Connection, transaction, commandType, commandText, commandParameters, MySqlConnectionOwnership.External);
        }

        #endregion ExecuteReader

        #region ExecuteScalar

        /// <summary>
        /// Execute a MySqlCommand (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 MySqlConnection</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 MySqlParameters
            return ExecuteScalar(connectionString, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (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 MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a MySqlConnection</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 MySqlParameter[] commandParameters)
        {
            //create & open a MySqlConnection, and dispose of it after we are done.
            using (MySqlConnection cn = new MySqlConnection(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 MySqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided MySqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteScalar(connection, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a 1x1 resultset) against the specified MySqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, connection, (MySqlTransaction)null, commandType, commandText, commandParameters);

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

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

        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided MySqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText)
        {
            //pass through the call providing null for the set of MySqlParameters
            return ExecuteScalar(transaction, commandType, commandText, (MySqlParameter[])null);
        }

        /// <summary>
        /// Execute a MySqlCommand (that returns a 1x1 resultset) against the specified MySqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        {
            //create a command and prepare it for execution
            MySqlCommand cmd = new MySqlCommand();
            PrepareCommand(cmd, (MySqlConnection)transaction.Connection, transaction, commandType, commandText, commandParameters);

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

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


        #endregion ExecuteScalar

        #region ExecuteXmlReader

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlConnection. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText)
        //{
        //pass through the call providing null for the set of MySqlParameters
        // return ExecuteXmlReader(connection, commandType, commandText, (MySqlParameter[])null);
        //}

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlConnection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connection">a valid MySqlConnection</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(MySqlConnection connection, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        //{
        //    //create a command and prepare it for execution
        //    MySqlCommand cmd = new MySqlCommand();
        //    PrepareCommand(cmd, connection, (MySqlTransaction)null, commandType, commandText, commandParameters);

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

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

        //}


        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset and takes no parameters) against the provided MySqlTransaction. 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText)
        //{
        //pass through the call providing null for the set of MySqlParameters
        //  return ExecuteXmlReader(transaction, commandType, commandText, (MySqlParameter[])null);
        //}

        /// <summary>
        /// Execute a MySqlCommand (that returns a resultset) against the specified MySqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new MySqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="transaction">a valid MySqlTransaction</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(MySqlTransaction transaction, CommandType commandType, string commandText, params MySqlParameter[] commandParameters)
        //{
        //    //create a command and prepare it for execution
        //    MySqlCommand cmd = new MySqlCommand();
        //    PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

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

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


        #endregion ExecuteXmlReader


        #region myself methods
        public static MySqlConnection GetConnection(String connectionString)
        {
            MySqlConnection cn = new MySqlConnection(connectionString);
            cn.Open();
            return cn;
        }

        #endregion mysel methods

    } 
}