I'm trying to GRANT ALL PRIVILEGES with php inside a loop. Each user should have full access to their corresponding Database. But for some reason GRANT ALL PRIVILEGES command returns false response.
   $dbArray = [new OnePDO,new TwoPDO];
   $dbNames = ['ONE_PDO','TWO_PDO'];
   for ($foo = 0; $foo < count($dbNames); $foo++) {
        $dbName = $dbNames[$foo];
        $pass = $util -> generateRandomPassword();
        $userName = strtolower($dbName);
        $userName = str_replace('_', '.', $userName);
        $util -> execute("CREATE USER '$userName'@'localhost' IDENTIFIED BY '$pass'", $dbArray[$foo]);
        $util -> execute("GRANT ALL PRIVILEGES ON $dbName.* TO '$userName'@'localhost'", $dbArray[$foo]));
        $util -> execute("FLUSH PRIVILEGES", $dbArray[$foo]);
   }
When trying to use the database...
Access denied for user 'one.pdo'@'localhost' to database 'ONE_PDO'
Adding this just for context...
   public function execute($query, $database) {
        $command = $database -> prepare($query);
        try {
            $command -> execute();
        } catch (Exception $e) {
            $command = false;
        }
        return $command;
    }