check_material_code.php

<?php
require_once 'includes/auth.php';
require_login();
require_csrf();
require_once 'includes/db.php';
$product_code = $_POST['product_code'] ?? '';
$stmt = $pdo->prepare("SELECT COUNT(*) FROM materials WHERE product_code = ?");
$stmt->execute([$product_code]);
$count = $stmt->fetchColumn();
header('Content-Type: application/json');
echo json_encode(['exists' => $count > 0]);