Transactions and Consistency

Ensure multi-step changes are atomic; make retries safe.

Commands

DB::transaction(function () use ($order, $payload) { $order->update([...]); $order->items()->createMany($payload['items']); OrderUpdated::dispatch($order); // or flag for after-commit });

// Listener queued after commit class SendInvoice implements ShouldQueue { public $afterCommit = true; }

Patterns

• Use DB::transaction to wrap write sequences and related side-effects

• Prefer $afterCommit or dispatchAfterCommit() for events / jobs

• Make jobs idempotent (check existing state, use unique constraints)

• Use lockForUpdate() for row-level coordination when needed

• Validate invariants at the boundary before starting the transaction