CQRSbased

CQRS-based refers to architectures that apply the Command Query Responsibility Segregation pattern, separating data mutating operations from data retrieval operations. In such systems, the write model processes commands — requests to create, modify, or delete data — and encapsulates the domain logic that enforces invariants. After handling a command, the write side typically publishes events that describe the state changes.

The read model provides fast, denormalized views optimized for queries. It is updated separately from the write model, often through event handlers or projection processes that transform the published events into queryable structures. This separation allows the read side to be scaled independently and to tailor data structures for specific query patterns.

Consistency between the write and read models is usually eventual, with updates propagating asynchronously. Strong consistency can be achieved with synchronous paths, but at the cost of latency and complexity. CQRS does not require event sourcing, but it is commonly used in conjunction with it, where the write model persists a sequence of events rather than the current state; the read model is rebuilt from those events.

Common motivations for adopting a CQRS-based approach include the need for scaling reads and writes separately, handling complex domain logic, and enabling independent evolution of the user interfaces and data schemas. Potential drawbacks include increased architectural complexity, coordination overhead, and the challenge of maintaining cross-cutting invariants across models.

CQRS-based systems are frequently found in microservices architectures and event-driven ecosystems, where clear boundaries and asynchronous communication are advantageous.