Ensuring Data Integrity with Eloquent Transactions

use Illuminate\Support\Facades\DB;
use App\Models\Order;
use App\Models\OrderItem;
use Exception;

try {
    DB::transaction(function () {
        // Step 1: Create a new order
        $order = Order::create([
            'user_id' => 1,
            'total_amount' => 0, // Will update later
            'status' => 'pending',
        ]);

        // Simulate multiple order items
        $itemsData = [
            ['product_id' => 101, 'quantity' => 2, 'price' => 15.00],
            ['product_id' => 102, 'quantity' => 1, 'price' => 25.00],
            // Imagine a third item fails
            // ['product_id' => 999, 'quantity' => 1, 'price' => 50.00],
        ];

        $total = 0;
        foreach ($itemsData as $itemData) {
            // Step 2: Create order items for the order
            $orderItem = new OrderItem($itemData);
            $orderItem->order_id = $order->id;
            $orderItem->save();
            $total += ($itemData['quantity'] * $itemData['price']);
        }

        // Step 3: Update order total
        $order->total_amount = $total;
        $order->save();

        // Simulate an error after successful operations to test rollback
        // throw new Exception('Simulated error during transaction.');

        echo "Order and order items created successfully!
";
    });
} catch (Exception $e) {
    // The transaction will automatically be rolled back here
    echo "Transaction failed: " . $e->getMessage() . "
";
    echo "Database changes were rolled back.
";
}

// Alternatively, using the Model's transaction method (PHP 8+ required for static closure binding)
// Order::transaction(function () {
//     $order = Order::create(['user_id' => 2, 'total_amount' => 0, 'status' => 'pending']);
//     // ... create order items ...
//     $order->total_amount = 100;
//     $order->save();
// });