为何调用函数时必须把数据库连接文件放在函数体里面

WBOY
Release: 2016-06-13 12:42:01
Original
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为什么调用函数时必须把数据库连接文件放在函数体里面
像下面这个程序:

<? <br />
header("Content-type: text/html; charset=gb2312"); <br />
<br />
  $act=$_GET["act"];<br />
<br />
if($act=="del")	{		 	//删除记录<br />
	$id =$_GET["id"];<br />
	require('conn.php');<br />
	$conn->query("delete from lyb where id=$id");<br />
	fy();	}<br />
<br />
if($act=="list") { fy();}<br />
<br />
function fy() {<br />
require('conn.php');<br />
 $sql="select * from lyb order by ID desc";<br />
	//echo $sql;<br />
<br />
$result=$conn->query($sql);}
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如果把 require('conn.php');写在函数的外面就不行,如下所示。这样如果有几个if语句的话,require('conn.php');就要重复写几遍,很不方便。我记得无参无返回值的函数,其实就相当于把该函数体中的代码插入到调用函数的位置处,但从这里看并不是这样的哦。

<? <br />
header("Content-type: text/html; charset=gb2312"); <br />
require('conn.php');<br />
  $act=$_GET["act"];<br />
<br />
if($act=="del")	{		 	//删除记录<br />
	$id =$_GET["id"];<br />
	$conn->query("delete from lyb where id=$id");<br />
	fy();	}<br />
<br />
if($act=="list") { fy();}<br />
<br />
function fy() {<br />
 $sql="select * from lyb order by ID desc";<br />
	//echo $sql;<br />
<br />
$result=$conn->query($sql);}
Copy after login

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