<?php

$sqlPass = '';
$sqlUser = 'root';
$sqlTable = 'cards';
$sqlDatabase = 'rfid';

$pdo_options[PDO::ATTR_ERRMODE] = PDO::ERRMODE_EXCEPTION;
$db = new PDO('mysql:host=127.0.0.1;dbname='.$sqlDatabase, $sqlUser, $sqlPass, $pdo_options);

$uid = isset($_GET['uid']) ? strtoupper($_GET['uid']):0;

$req = $db->prepare('SELECT count(id) AS nb FROM '.$sqlTable.' WHERE uid = ?');
$req->execute(array($uid));
$data = $req->fetch();

if($data['nb'])
    echo 1;
else
    echo 0;

?>