为什么显示pdo未定义？

Question

我有一个数据库连接的脚本是

<?php 

//$dsn ='mysql:dbname=medicare;host=localhost'; 
$me = "root"; 
$password =""; 

try{ 
$pdo = new PDO('mysql:host=localhost;dbname=medicare',$me,$password); 
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
} 
catch(PDOException $e){ 
echo"Error!:".$e->getMessage()."<br>"; 
die(); 


} 

?> 

然后我有一个函数在db_operations类，它是

public static function insert_admin($name,$pass){ 
// require_once("/connect.php"); 
$security = "?..H@Si./n/?"; 
$pass = md5($pass,PASSWORD_DEFAULT).$security; 
$sql = "INSERT INTO admin(username,password) VALUES(:username,:password)"; 

$stmt = $pdo->prepare($sql); (line 79) 
$stmt->bindParam(':username',$name,PDO::PARAM_STR); 
$stmt->bindParam(':password',$pass,PDO::PARAM_STR); 
$stmt->execute(); 

$pdo = null; 


} 

添加数据，但它已表现出

Notice: Undefined variable: pdo in F:\xampp\htdocs\medicare\Model\class_db_operations.php on line 79

Fatal error: Call to a member function prepare() on a non-object in F:\xampp\htdocs\medicare\Model\class_db_operations.php on line 79 someone please help.

Answer 1

有当调用$pdo->prepare()时，定义为$pdo，您需要将其作为参数传递或使其在对象中可用一个属性，并用另一种方法设置它。

Answer 2

public static function insert_admin($name,$pass){ 
// require_once("/connect.php"); 
global $pdo; 
$security = "?..H@Si./n/?"; 
$pass = md5($pass,PASSWORD_DEFAULT).$security; 
$sql = "INSERT INTO admin(username,password) VALUES(:username,:password)"; 

$stmt = $pdo->prepare($sql); (line 79) 
$stmt->bindParam(':username',$name,PDO::PARAM_STR); 
$stmt->bindParam(':password',$pass,PDO::PARAM_STR); 
$stmt->execute(); 

$pdo = null; 


} 

你为什么要在最后设置$ pdo为null？