使用PDO :: PARAM_LOB将图像上传到MariaDB表中的INSERT失败

Question

My problem is that when I use the PDO::PARAM_LOB parameter in the bindParam() method the photo sent from the html form isn’t inserted in the MariaDB table. phpMyAdmin subsequently shows the table column ‘photo’ to be empty. The image is successfully inserted in the table when I don’t use the PDO::PARAM_LOB but this causes a Notice: Array to string conversion in C:\xampp\htdocs\TestSite\php-sellform-handler.php on line 80 to display to the user on the web page. There are other fields on the same form (which for simplicity I haven’t shown) which upload text and use PDO::PARAM_STR. This text data is always successfully inserted in the same table. How do I get insert to work using PDO::PARAM_LOB?

The nearest problem to mine that I can find on S/O is PHP/PDO/MySQL: inserting into MEDIUMBLOB stores bad data However that involves the image actually being inserted in the table, but in a corrupted form.

I’m using Apache/2.4.29 (Win32) OpenSSL/1.1.0g PHP/7.2.2 and 10.1.30-MariaDB

Here is my code:

$host = '127.0.0.1';
$db = 'test_db2';
$user = 'root';
$pass = '';
$charset = 'utf8mb4';

    $dsn = "mysql:host=$host;dbname=$db;charset=$charset";



$opt = [PDO::ATTR_ERRMODE =>PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES => false 
    ];


$pdo=new PDO($dsn, $user, $pass, $opt);



if (isset($_FILES ['photo'])) {

$photo=$_FILES['photo'];


$stmt_user = $pdo->prepare("INSERT INTO users_table1(photo) VALUES(:photo)");

$stmt_user->bindParam(':photo', $photo, PDO::PARAM_LOB);    

$stmt_user->execute();
}

Thanks for any help!