PHP操作Mysql

<?php
//mysql数据库通用类
    class Mysql_Oper
    {
        private $hostname='127.0.0.1';
        private $username='root';
        private $password='52ebook';
        private $dbname='b_work';
        private $conn;
        function __construct()
        {
            $conn=mysql_connect($this->hostname,$this->username,$this->password);
            mysql_select_db($this->dbname,$conn);
            
            if(!$conn)
            {
                echo $conn->error();
                die;
            }
            //设置编码
            mysql_query("SET NAMES 'utf8'");
        }
        
        //实现数据查询，返回所有数据
        public function QueryAll($sql,$resultmode='assoc')
        {
            $datatable;
            $result=mysql_query($sql);
            $mode=$resultmode;
            switch($result_mode)
                {
                    case 'assoc':
                    $mode=MYSQL_ASSOC;
                    break;
                    case 'num':
                    $mode=MYSQL_NUM;
                    break;
                    case 'both':
                    $mode=MYSQL_BOTH;
                    break;
                }
            //在mysql驱动中没有fetch_all函数，循环实现
            while($row=mysql_fetch_row($result,$mode))
            {
                $datatable[]=$row;
            }
            return $datatable;
        }
        
        //返回影响的行数
        public function QueryAffected($sql)
        {
            mysql_query($sql);
            return mysql_affected_rows();
        }
        //第一行数据
        function QueryFirstRow($sql)
        {
            $result=mysql_query($sql);
            return mysql_fetch_row($result);
        }
        //获取上一次插入的id号
        function QueryInsertid($sql)
        {
            mysql_query($sql);
            return mysql_insert_id();
        }
        function __destruct()
        {
            mysql_close($this->conn);
        }
    }
    ?>