DDD Aggregate Transaction Boundary

One transaction should update one aggregate. If multiple aggregates must change, model coordination explicitly.

Workflow

1. Identify every aggregate loaded or modified by the use case.

2. Mark which aggregate owns the command's true invariant.

3. Keep that aggregate in the synchronous transaction.

4. Move other aggregate updates behind domain events, an outbox, a saga, or a process manager.

5. Define compensating behavior for failures and retries.

Checks

• A use case that saves two aggregate roots is suspect.