PHP/PDO語句使「0」

Question

我使用貝寶IPN，這是我如何將數據發送到貝寶：

require_once 'classes/Crypt.php'; 

$crypt = new Crypt(); 
$crypt->Mode = Crypt::MODE_HEX; 
$crypt->Key = '§$TERGERG§$T§34t'; 

$test = array('cmd'=>'_xclick', 
       'business'=>'meine_email', 
       'notify_url'=> 'url_zum_ipn', 
       'item_name'=>'name', 
       'amount'=>'1.00', 
       'currency_code'=>'USD', 
       'lc'=>'US', 
       'custom'=>$crypt->encrypt(serialize(array("username" => $username)))); 

       $url = "https://www.sandbox.paypal.com/cgi-bin/webscr?".http_build_query($test); 
       header("Location:".$url); 
       exit(); 

這是我如何處理我的IPN腳本數據：

require_once '../classes/Crypt.php'; 

$crypt = new Crypt(); 
$crypt->Mode = Crypt::MODE_HEX; 
$crypt->Key = '§$TERGERG§$T§34t'; 

$custom = unserialize($crypt->decrypt($_POST["custom"])); 

$username = $custom['username']; 

try 
{ 
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
    $stmt = $dbh->prepare("INSERT INTO products (product_name) 
            VALUES (?)"); 
    $stmt->bindParam(1, $value1); 

    $value1 = $username; 

    $stmt->execute(); 
} 
catch(PDOException $exception) 
{ 
    $body .= "Error: " . $exception->getMessage() . "\n"; 
} 

沒有插入我的表，但此消息：

Error: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 
'product_name' cannot be null 

我檢查變量$用戶名在開始發送時，它是！ 但我對這個檢查變量$的用戶名在IPN腳本：

if($username == "") { // gives true 

所以任何人知道哪裏是我的錯誤的代碼？問候！

Answer 1

更換

$stmt = $dbh->prepare("INSERT INTO products (product_name) 
           VALUES (?)"); 
$stmt->bindParam(1, $value1); 

$value1 = $username; 

$stmt->execute(); 

有了：

$stmt = $dbh->prepare("INSERT INTO products(product_name) VALUES(:productName)"); 
$stmt->execute([':productName' => $username]);