- CQRS is the broader architectural pattern, and CQS is the general principle of behaviour
- CQRS takes the defining principle of CQS and extends it to specific objects within a system
- CQS works more on the method or class level, whilst CQRS takes the concepts of CQS and takes it to the application level
- CQRS allows for separate data stores and models for Commands and Queries and usually synchronized asynchronously using a service bus
- CQRS extends this concept into a higher level for machine-machine APIs, separation of the message models and processing paths