php数据库常用操作类

<?php
class phpCMS_MySQL  {
     var $servername="localhost";
     var $DBusername="root";
     var $DBpassword="";
     var $DBname="phpcms";
     var $id = 0;
     var $link_id = 0;
     var $query_id = 0;
     var $querycount = 0;
     var $result;
     var $record = array();
     var $rows;
    
     function Connect(){
               $this->ConnStr=mysql_connect($this->servername,$this->DBusername,"");
               if(!$this->ConnStr)
               {
               echo "数据库连接失败!";
               }              
               return $this->ConnStr;
      }
     function SelectDB(){
               if(!mysql_select_db($this->DBname)){
                   echo "数据库链接失败";
               }
      }
      function query($query_string) {
               $this->result = mysql_query($query_string,$this->ConnStr);
               if (!$this->result) {
                   echo "SQL 无效: ".$query_string;
               }
               return $this->result;
      }
      function fetch_array($queryid) {
               $this->record = mysql_fetch_array($queryid);
               if (empty($queryid)){
                   echo "Query id 无效:".$queryid;
               }
               return $this->record;
      }
      function num_rows($queryid) {
               $this->rows = mysql_num_rows($queryid);
               if (empty($queryid)){
                   $this->halt("Query id 无效:".$queryid);
               }
               return $this->rows;
      }
      }
大家帮我看看有没有问题