(SQL SERVER) (ORACLE) (ACCESS)(POSTGRE SQL)四种数据库操作C#代码

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将对这四种数据库的操作封装到了2个类中可以拷贝过去直接使用。
   public sealed class OleDbClass    {        #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 OleDbClass() { }        /// <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))            {                cn.Open();                //call the overload that takes a connection in place of the connection string                return ExecuteNonQuery(cn, commandType, commandText, commandParameters);            }        }        /// <summary>        /// Execute a stored procedure via a SqlCommand (that returns no resultset) against the database specified in         /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the         /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.        /// </summary>        /// <remarks>        /// This method provides no access to output parameters or the stored procedure's return value parameter.        ///         /// e.g.:          ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);        /// </remarks>        /// <param name="connectionString">a valid connection string for a SqlConnection</param>        /// <param name="spName">the name of the stored prcedure</param>        /// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>        /// <returns>an int representing the number of rows affected by the command</returns>        public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)        {            //if 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 = SqlParameterClass.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 = SqlParameterClass.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 = SqlParameterClass.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))            {                cn.Open();                //call the overload that takes a connection in place of the connection string                return ExecuteDataset(cn, commandType, commandText, commandParameters);            }        }        public static DataTable ExecuteDataset_oracle(string connectionString, CommandType commandType, string commandText)        {            DataTable Dt = new DataTable();            using (OracleConnection mConn = new OracleConnection(connectionString))            {                mConn.Open();                OracleCommand cmd = new OracleCommand(commandText, mConn);                OracleDataAdapter dap = new OracleDataAdapter(cmd);                dap.Fill(Dt);                mConn.Close();            }            return Dt;        }        public static DataTable ExecuteDataset_PostgreSQL(string connectionString, CommandType commandType, string commandText)        {           DataTable Dt = new DataTable();            try            {                using (NpgsqlConnection mConn = new NpgsqlConnection(connectionString))                {                    NpgsqlCommand comm = new NpgsqlCommand(commandText, mConn);                    mConn.Open();                                        NpgsqlDataAdapter sda = new NpgsqlDataAdapter();                    sda.SelectCommand = comm;                    sda.Fill(Dt);                    mConn.Close();                }            }            catch (Exception)            {                return null;            }            return Dt;        }        public static int Execute_PostgreSQL(string connectionString, CommandType commandType, string commandText)        {            int ret;            try            {                using (NpgsqlConnection mConn = new NpgsqlConnection(connectionString))                {                    NpgsqlCommand comm = new NpgsqlCommand(commandText, mConn);                    try                    {                        mConn.Open();                    }                    catch                    {                        return -2;                    }                    ret = comm.ExecuteNonQuery();                    mConn.Close();                }            }            catch (Exception)            {                return 0;            }            return ret;        }        public static DataTable ExecuteDataset_oracle(string connectionString, string commandText)        {            DataTable Dt = new DataTable();            using (OracleConnection mConn = new OracleConnection(connectionString))            {                mConn.Open();                OracleCommand cmd = new OracleCommand(commandText, mConn);                OracleDataAdapter dap = new OracleDataAdapter(cmd);                dap.Fill(Dt);                mConn.Close();            }            return Dt;        }        /// <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 = SqlParameterClass.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            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 = SqlParameterClass.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 = SqlParameterClass.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            {                //if we fail to return the SqlDatReader, we need to close the connection ourselves                cn.Close();                throw;            }        }        /// <summary>        /// Execute a stored procedure via a SqlCommand (that returns a resultset) against the database specified in         /// the connection string using the provided parameter values.  This method will query the database to discover the parameters for the         /// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.        /// </summary>        /// <remarks>        /// This method provides no access to output parameters or the stored procedure's return value parameter.        ///         /// e.g.:          ///  SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);        /// </remarks>        /// <param name="connectionString">a valid connection string for a SqlConnection</param>        /// <param name="spName">the name of the stored procedure</param>        /// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>        /// <returns>a SqlDataReader containing the resultset generated by the command</returns>        public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)        {            //if 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 = SqlParameterClass.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 = SqlParameterClass.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 = SqlParameterClass.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 = SqlParameterClass.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();            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 = SqlParameterClass.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();            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 = SqlParameterClass.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 = SqlParameterClass.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 = SqlParameterClass.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        public static int OleDbExecuteNonQuery(string connectionString, string commandText)        {            //create & open a SqlConnection, and dispose of it after we are done.            using (OleDbConnection cn = new OleDbConnection(connectionString))            {                try                {                    cn.Open();                }                catch (Exception)                {                    return -1;                }                OleDbCommand myCommand = new OleDbCommand(commandText, cn);                int ret=myCommand.ExecuteNonQuery();                cn.Close();                return ret;                //call the overload that takes a connection in place of the connection string            }        }        public static DataSet OleDbExecuteDataset(string connectionString, string commandText)        {            //create & open a SqlConnection, and dispose of it after we are done.            using (OleDbConnection cn = new OleDbConnection(connectionString))            {                try                {                    cn.Open();                    OleDbCommand myCommand = new OleDbCommand(commandText, cn);                    OleDbDataAdapter da = new OleDbDataAdapter(myCommand);                    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.                    myCommand.Parameters.Clear();                    //return the dataset                    cn.Close();                    return ds;                    //call the overload that takes a connection in place of the connection string                }                catch (Exception)                {                    cn.Close();                    return null;                }            }        }    }
  public sealed class SqlParameterClass    {        #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 SqlServerClass()".        private SqlParameterClass() { }        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);                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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