PHP mysql：注册返回false

Question

I am trying to enter values in the database from two textboxes yet when I submit the username and password i get this error: user has not been entered on the database check with administrator of the system.

<?php
    session_start();
    $logged_in = isset($_SESSION['USERNAME']) && $_SESSION['USERNAME'] ?
 $_SESSION['USERNAME'] : null;
    if(!$logged_in) {   
    }
error_reporting(E_ALL & ~E_NOTICE);
include 'dbconfig.php';

     global $db;


$username=$_POST['username'];
$password=$_POST['password'];

// encrypting password
$encrypted_password=md5($password);

$stmt = $db->prepare("SELECT * FROM user_info WHERE username = ?");
$stmt->execute(array($username)); 
$row = $stmt->fetch(PDO::FETCH_ASSOC);



if (! $row){

//add new user to database
$stmt = $db->prepare("INSERT INTO user_info(username, password) VALUES (?,?)");
$params1 = array($username, $encrypted_password);



if (!$stmt ->execute($params1)){
echo "user has not been entered on the database check with administrator of the system.  
<span class='label label-important'>Important</span>";

}else{
echo $username." has been added to the database as a supervisor. <span class='label 
label-success'>Success</span>";


}
else{
echo $username." is already a user of the system <span class='label label- 
warning'>Warning</span>";

}
$db = null; 
?>

var_dump($row); returns a false boolean and it will not load the values into the database. Any ideas? thanks.

Answer 1

From your code it is not fully understandable where is the error.

But,

as you get error in

if (!$stmt ->execute($params1)){

statement, I assume that it is a database related error.

So first check what is the size of username field in the table. make a maxlength checking in user input against the field.

Also, to note, a md5 password encryption returns near 30 characters. So it is safe to make your password field 50 char long.

Also there may be other causes for the error, but please confirm those above first and try it again.

Thanks