我的代码有什么问题，mysql，PDO准备删除语句？

Question

Why my code is not working. Help, I don't see any wrong. If I use user_id=$current_user instead of user_id=:current_id, it works. But I need to prepare for security reason. Help please.

<?php
$hostname = 'localhost';
$username = '**';
$password = '**';
$dbname = '**';
try {
    $db = new PDO("mysql:host=$hostname;dbname=$dbname", "$username" ,"$password" , 
        array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));

} catch (PDOException $e) {
    echo" There was an error with the connection";
}

$current_user=$_POST['users_id'];//get user id

include 'db_tag.php';
$stmt=$db->prepare("DELETE FROM object_sign WHERE user_id=:current_id");

$stmt->bindParam(":current_id",$current_user,PDO::PARAM_INT);
$stmt->execute(); 

?>

Answer 1

@conan, Use below code that I have mentioned & you need to check below points with this code.

1) Print $current_user id to make sure id correctly appeared or not,Also I have put condition if post contain user id then only query being executed.

2) I have put exception so you can check errors through exception message.

<?php
include 'db_tag.php';

$hostname = 'localhost';
$username = '**';
$password = '**';
$dbname = '**';

try {
     $db = new PDO("mysql:host=$hostname;dbname=$dbname", "$username" ,"$password" , 
        array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));

    if(isset($_POST['users_id'])) {
        $current_user=$_POST['users_id'];//get user id

        $stmt=$db->prepare("DELETE FROM object_sign WHERE user_id=:user_id");

        $stmt->bindParam(":user_id",$current_user);
        $stmt->execute(); 
    } 
} catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}
?>