警告：mysqli的:: mysqli的（）（HY000/1044）：拒絕訪問用戶

Question

if (!defined('$servername')) define('$servername', 'localhost'); 
if (!defined('$username')) define('$username', 'username'); 
if (!defined('$password')) define('$password', 'password'); 
if (!defined('$dbname')) define('$dbname', 'my_db'); 

$conn = new mysqli($servername, $username, $password, 'my_db'); 

錯誤：

Notice: Undefined variable: servername in C:\Program Files (x86)\XAMPP\htdocs\amit\Databas.php on line 10 

Warning: mysqli::mysqli(): (HY000/1044): Access denied for user ''@'localhost' to database 'my_db' in C:\Program Files (x86)\XAMPP\htdocs\amit\Databas.php on line 10 
Connection failed: Access denied for user ''@'localhost' to database 'my_db' 
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$conn = new mysqli($servername, $username, $password, $dbname); 
Notice: Undefined variable: dbname in C:\Program Files (x86)\XAMPP\htdocs\amit\Databas.php on line 10/
on the top of the page 
__________________________________________________ 
$conn = new mysqli('localhost', 'username', 'password', 'my_db'); 
errors: 
Warning: mysqli::mysqli(): (HY000/1045): Access denied for user 'username'@'localhost' (using password: YES) in C:\Program Files (x86)\XAMPP\htdocs\amit\Databas.php on line 10 
Connection failed: Access denied for user 'username'@'localhost' (using password: YES) 

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我已經創建了localhost:82/phpmyadminmy_db ...

我也創建了一個user=username，與password=password ...

此外，如果我改變th Ëif (!defined('$servername')) define('$servername', 'localhost');到define('$servername','localhost');我得到：

我除了不確定的服務器和數據庫網站的頂部已定義的變量

Answer 1

你確定他們走錯了路，試試這個例子：

if (!defined('SERVERNAME')) define('SERVERNAME', 'localhost'); 
    if (!defined('USERNAME')) define('USERNAME', 'username'); 
    if (!defined('PASSWORD')) define('PASSWORD', 'password'); 
    if (!defined('DBNAME')) define('DBNAME', 'my_db'); 

    $conn = new mysqli(SERVERNAME, USERNAME, PASSWORD, 'my_db');