将数据库常用的操作（连接数据库，获得所有数据，获得一条记录，获得一列记录，获得一条索引数组，获得一条关联数组）都给封装到db.class.php里面，谁需要谁继承这个类 注意：提交封装的类文件

<?php

class dbname{

private $localhost;

private $root;

private $pass;

private $db_name;

public function __construct($localhost,$root,$pass,$db_name){

$this->localhost=$localhost;

$this->root=$root;

$this->pass=$pass;

$this->db_name=$db_name;

$this->query();

}

private function query(){

mysql_connect($this->localhost,$this->root,$this->pass);

mysql_select_db($this->db_name);

mysql_query("set names utf8");

}

public function getAll($sql){

$result = mysql_query($sql);

$rows=array();

while($row = mysql_fetch_assoc($result)){//返回的是多条记录

$rows[]=$row;

}

return $rows;

}