为什么我的pdo变量始终未定义？(Why is my pdo variable all the time undefined? [duplicate])

这个问题在这里已经有了答案：

PDO致命错误：调用成员函数prepare（）上的非对象 3答案参考：什么是变量作用域，哪些变量可以从哪里访问，什么是“未定义变量”错误？ 3个答案调用成员函数prepare（）上的非对象PHP Help 8的答案

我有两个php文件，一个是PDO连接的文件，另一个是准备好的语句在此连接上提交的文件：

PDO连接：

class Connection { protected $user = "ni873420_2sql1"; protected $pass = "#"; public $pdo_log; public function __construct() { try { $pdo_log = new PDO('mysql:host=localhost;dbname=ni873420_2sql1', $this->user, $this->pass); } catch (Exception $e) { die($e); } } }

这是我创建准备好的声明的功能：

public static function getInfobyEmailUsername($argemailusername) { $get_info_query = "SELECT * FROM user WHERE email = ? OR username = ?"; $conn = new Connection(); $getinfostmt = $conn->pdo_log->prepare($get_info_query); $getinfostmt->execute(array($argemailusername, $argemailusername)); $userinfo = $getinfostmt->fetch(PDO::FETCH_ASSOC); if (!empty ($userinfo)) { return $userinfo; } else { return false; } }

但我不断收到错误：

Fatal error: Call to a member function prepare() on null

我无法找到任何解决方案，任何人都可以帮助我或至少发送一个链接，我可以找到解决方案？

谢谢！

This question already has an answer here:

PDO Fatal error: Call to a member function prepare() on a non-object 4 answers Reference: What is variable scope, which variables are accessible from where and what are “undefined variable” errors? 3 answers Call to a member function prepare() on a non-object PHP Help 8 answers

I have two php files, one is a file for a PDO Connection and one is a file in which a prepared statement is submitted on this connection:

PDO Connection:

class Connection { protected $user = "ni873420_2sql1"; protected $pass = "#"; public $pdo_log; public function __construct() { try { $pdo_log = new PDO('mysql:host=localhost;dbname=ni873420_2sql1', $this->user, $this->pass); } catch (Exception $e) { die($e); } } }

And this is the function where I create the prepared statement:

public static function getInfobyEmailUsername($argemailusername) { $get_info_query = "SELECT * FROM user WHERE email = ? OR username = ?"; $conn = new Connection(); $getinfostmt = $conn->pdo_log->prepare($get_info_query); $getinfostmt->execute(array($argemailusername, $argemailusername)); $userinfo = $getinfostmt->fetch(PDO::FETCH_ASSOC); if (!empty ($userinfo)) { return $userinfo; } else { return false; } }

But I keep getting the error:

Fatal error: Call to a member function prepare() on null

I cant find a solution anywhere, can anyone help me with this or at least send a link where I can find the solution?

Thank you!