Checking Username Exists

[Hendz]

Hi Guys ive given this a go and im continuing to learn php.

I want to check from a login section to see does the username exist in the database.

Ive gotten this far but i feel like im miles away. Any suggestions would be appreciated.

 

<?php require "config.php";

try { $pdo = new PDO("mysql:host=$host", $username, $password, $options);

echo 'DB connected'; }

catch (PDOException $e) { throw new PDOException($e->getMessage(), (int)$e->getCode()); }

$stmt = $pdo->query('SELECT username FROM databasetest.login WHERE username = !null');

while ($row = $stmt->fetch()) {

 

echo "\n" . PHP_EOL;

echo "<br>" . PHP_EOL;

echo $row['username']; }

[Barand]

You don't say what the problem is, but

WHERE username = !null       - WRONG
WHERE username IS NOT NULL   - CORRECT;

 

[Strider64]

        $pwd = password_hash($data['password'], PASSWORD_DEFAULT);
        unset($data['password']);
        try {
            $query = 'INSERT INTO users (fullName, username, status, password, security, email, date_added) VALUES (:fullName, :username, :status, :password, :security, :email, Now())';
            $stmt = Database::pdo()->prepare($query);
            $result = $stmt->execute([':fullName' => $data['fullName'], ':username' => $data['username'], ':status' => $data['status'], ':password' => $this->pwd, ':security' => 'newuser', ':email' => $data['email']]);
        } catch (PDOException $e) {

            /*
             * echo "unique index" . $e->errorInfo[1] . "<br>";
             *
             * An error has occurred if the error number is for something that
             * this code is designed to handle, i.e. a duplicate index, handle it
             * by telling the user what was wrong with the data they submitted
             * failure due to a specific error number that can be recovered
             * from by the visitor submitting a different value
             *
             * return false;
             *
             * else the error is for something else, either due to a
             * programming mistake or not validating input data properly,
             * that the visitor cannot do anything about or needs to know about
             *
             * throw $e;
             *
             * re-throw the exception and let the next higher exception
             * handler, php in this case, catch and handle it
             */

            if ($e->errorInfo[1] === 1062) {
                return false;
            }

            throw $e;
        } catch (Exception $e) {
            echo 'Caught exception: ', $e->getMessage(), "\n"; // Not for a production server:
        }

If you really want to make sure there can be no duplicates then create an unique index for the username and throw an PDO exception if a duplicate is found. Though I think this would only be useful for a busy busy website.