PDO if语句验证

Question

What am I doing wrong here? All the data was subitting until I added the last part of the code, the IF(){} statement. I want to make it where if the information was submitted correctly, for it to say THANK YOU!, else, display the error i set.

<form method="POST">
    <input type="text" name="username" placeholder="username"><br />
    <input type="password" name="password" placeholder="password"><br />
    <input type="submit">
</form>

<?php
    if(isset($_POST['username'], $_POST['password'])){
        require 'core/db.php';

        $conn = dbConnect()->prepare("INSERT INTO users (username, password) VALUES (?,?)");

        $conn->bindParam(1, $_POST['username']);
        $conn->bindParam(2, $_POST['password']);
        $conn->execute();

        if($conn === true){
            echo 'Thanks!';
            header('Location: index.php');
            exit;
        } else{
            echo 'something went wrong';
        }
    }
?>

Answer 1

It's not the $conn that you should checking for true against. $conn is instance of PDOStatement. You should instead be checking the return value of $conn->execute().

if($conn->execute() === true){
  header('Location: index.php');
  exit;
} else{
  echo 'something went wrong';
}

As @mjayt pointed you should not output content before header call. You could definitely output using output buffering ob_start()...ob_end_flush(), but I do not assume the echo is really necessary here.