php 比较全的数据库操作类

<?php
    class database
    {
        private $hostname;
        private $user;
        private $pass;
        private $dbname;
        private $linkflag;
        private $charset;

        function __construct()
        {
            $this->hostname="localhost";
            $this->user="root";
            $this->pass="111";
            $this->dbname="";
            $this->charset="utf8";   //gb2312 GBK utf8
            $this->linkflag=mysql_connect($this->hostname,$this->user,$this->pass);
            mysql_select_db($this->dbname,$this->linkflag) or die($this->error());
            mysql_query("set names ".$this->charset);
        }

        function __set($property_name,$value)
        {
            return $this->$property_name=$value;
        }

        function __get($property_name)
        {
            if(isset($this->$property_name))
            {
                return $this->$property_name;
            }
            else return null;
        }

        function __call($function_name, $args)
        {
             echo "<br><font color=#ff0000>你所调用的方法 $function_name 不存在</font><br>\\n";
        }

        function query($sql)
        {
            $res=mysql_query($sql) or die($this->error());
            return $res;
        }

        function fetch_array($res)
        {
            return mysql_fetch_array($res);
        }

        function fetch_object($res)
        {
            return mysql_fetch_object($res);
        }

        function fetch_obj_arr($sql)
        {
            $obj_arr=array();
            $res=$this->query($sql);
            while($row=mysql_fetch_object($res))
            {
                $obj_arr[]=$row;
            }
            return $obj_arr;
        }

        function error()
        {
            if($this->linkflag)
            {
                return mysql_error($this->linkflag);
            }
            else    return mysql_error();
        }

        function errno()
        {
            if($this->linkflag)
            {
                return mysql_errno($this->linkflag);
            }
            else    return mysql_errno();
        }

        function affected_rows()
        {
            return mysql_affected_rows($this->linkflag);
        }

        function num_rows($sql)
        {
            $res=$this->execute($sql);
            return mysql_num_rows($res);
        }

        function num_fields($res)
        {
            return mysql_num_fields($res);
        }

        function insert_id()
        {
            $previous_id=mysql_insert_id($this->linkflag);
            return $previous_id;
        }

        function result($res,$row,$field=null)
        {
            if($field===null)
            {
                $res=mysql_result($res,$row);
            }
            else    $res=mysql_result($res,$row,$field);
            return $res;
        }

        function version()
        {
            return mysql_get_server_info($this->linkflag);
        }

        function data_seek($res,$rowNum)
        {
            return mysql_data_seek($res,$rowNum);
        }

        function __destruct()
        {
            //mysql_close($this->linkflag);
        }

    }

?>
//该片段来自于http://outofmemory.cn