PHP面向对象----继承特性

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 db

{

private $hostname;

private $user;

private $pass;

private $dbname;

private $linkflag;

private $charset;

public function __construct($host,$user,$pass,$dbname,$charset)

{

$this->hostname=$host;

$this->user=$user;

$this->pass=$pass;

$this->dbname=$dbname;

$this->charset=$charset;

$this->linkflag=mysql_connect($this->hostname,$this->user,$this->pass);

mysql_select_db($this->dbname,$this->linkflag) or die('连接失败！');

mysql_query("set names ".$this->charset);

}

public function getAll($sql){

$result = mysql_query($sql);

$rows = array();

while($row=mysql_fetch_assoc($result)){

$rows[] = $row;

}

return $rows;

}

public function getOne($sql){

$result = mysql_query($sql);

$row = mysql_fetch_assoc($result);

return $row;

}

public function __destruct()

{

mysql_close($this->linkflag);

}

}

?>