一个简单的php mysql操作类

<?php 
/**
* php、mysql连接类
* by bbs.it-home.org
*/
//----
/*
include "database.php"; //数据库配置信息

$db_host="localhost"; 
$db_user="user"; 
$db_pass="user"; 

$username=$_POST["txtUserName"]; 
$password=$_POST["txtPassword"]; 

$dbobj=new db; 
$dbobj->db_connect($db_host, $db_user, $db_pass,$db_name); 
$query="insert db_user values('$username','$password')"; 
$result=$dbobj->db_updateData($query); 
*/ 

class db 
{ 

var $query; 
var $numrows; 
  function db_connect($db_host, $db_user, $db_pass,$db_name)  
  { 
  global $ln; 
  global $result; 

  $db_host1=$db_host; 
  $db_user1=$db_user; 
  $db_pass1=$db_pass; 
  $db_name1=$db_name; 

 $ln = mysql_connect($db_host1, $db_user1, $db_pass1) or die("cannot connect"); 
 mysql_select_db($db_name1,$ln); 
  } 

  function db_selectData($query) 
  { 
global $ln; 
  global $result; 

  $this->query=$query; 
  $result= mysql_query($this->query,$ln); 
  return $result; 
  
  } 

  function db_deleteData($query) 
  { 
  global $ln; 
  global $result; 

 $this->query=$query; 
 $result= mysql_query($this->query,$ln); 
 return $result; 
  } 

  function db_updateData($query) 
  { 
   global $ln; 
 global $result; 
   $this->query=$query; 
 $result= mysql_query($this->query,$ln); 
 return $result; 

  } 

  function db_countRows($res) 
  { 
  global $ln; 
  global $result; 
  $this->numrows = mysql_num_rows($result); 
  return $this->numrows; 
  } 

  function db_close() 
  { 
  global $ln; 
  mysql_close($ln); 
  } 
}
?>