Following event-driven architectures, the write and read systems communicate solely via events. The events are distributed via an event store or event hub. There is no other coupling than the write systems that produce events and both write and read systems that consume for events to update their internal state.
The following snippet shows the architecture of a CQRS system:
The command and query services consume events from the event store. This is the only way for communication between them.
All services maintain a current-state representation that reflects the state of the domain entities. Entities are, for example, meal orders or ...
