public string ExecDataTableStr(IDbCommand command)
        {
            DataTable dtt = ExecDataTable(command);

            if ((dtt == null) || (dtt.Rows.Count < 1))
            {
                return(string.Empty);
            }
            else
            {
                return(GDataTypeConverter.DbToStr(dtt.Rows[0][0]));
            }
        }
        public string ExecScalarStr(IDbCommand command)
        {
            string result = string.Empty;

            if (_auto_open_close)
            {
                Open();
            }
            command.Connection     = _connection;
            command.CommandTimeout = _command_timeout;
            result = GDataTypeConverter.DbToStr(command.ExecuteScalar());
            if (_auto_open_close)
            {
                Close();
            }
            return(result);
        }