<?php
require_once __DIR__ . '/../config.php';
$pdo = db();

try {
    $pdo->exec("ALTER TABLE shipments ADD COLUMN shipper_id INT NULL AFTER id");
    $pdo->exec("ALTER TABLE shipments ADD COLUMN truck_owner_id INT NULL AFTER offer_price");
    
    // Add FK constraints (optional but good practice, keeping it simple for now to avoid issues with existing data)
    // We won't enforce FK strictly on existing data as it might be NULL
    
    echo "Added shipper_id and truck_owner_id to shipments table.";
} catch (PDOException $e) {
    echo "Error (might already exist): " . $e->getMessage();
}