Architecture also: Command Query Responsibility Segregation

CQRS

Separate read and write models, often backed by different stores.

In plain terms

Pairs naturally with event sourcing. Read side can be denormalised, indexed, or materialised differently from the write side.

Origin

Greg Young introduced "Command Query Responsibility Segregation" as a refinement of Bertrand Meyer's 1988 CQS principle. Pairs naturally with event sourcing.

Where it shows up in production

EventStore Greg Young's company; the canonical CQRS+event-sourcing reference.
Axon Framework (Java) Opinionated CQRS+ES framework; widely used in financial services.

Sources & further reading

Blog Martin Fowler — CQRS

Found this useful?