<?php
require 'db/config.php';
$tables = ['invoices', 'invoice_items', 'pos_transactions', 'pos_items', 'payments', 'pos_payments'];
foreach ($tables as $t) {
    echo "Table: $t\n";
    try {
        $res = db()->query("DESCRIBE $t");
        while ($r = $res->fetch(PDO::FETCH_ASSOC)) {
            echo "  {$r['Field']} ({$r['Type']})\n";
        }
    } catch (Exception $e) {
        echo "  Error: " . $e->getMessage() . "\n";
    }
}