PHP会话页面保护无法正常运行

Question

这是登录PHP代码

<?php
session_start();

if( isset($_SESSION['user_id']) ){
header("Location: index.php");
}

require 'database.php';

if(!empty($_POST['username']) && !empty($_POST['password'])):

$records = $conn->prepare('SELECT id,user,password FROM users WHERE user = :user'); 
$records->bindParam(':user', $_POST['username']);
$records->execute();
 $results = $records->fetch(PDO::FETCH_ASSOC);

  $message = '';

 if(count($results) > 0 && md5($_POST['password'],     $results['password'])     ){

    $_SESSION['user_id'] = $results['id'];
    header("Location: index.php");

    } else {
        $message = 'Sorry, something went wrong';
    }
?>

这是应该保护我的页面

<?php
session_start();

if(!isset($_SESSION['user_id']) || $_SESSION['user_id']!=1){
header('Location: login.php');
}
?>

即使我登录，它也会将我重定向到我的login.php。 我错过了什么？