php实现比较全的数据库操作类_php技巧

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);  } }?>