CQRS and Event Sourcing#

CQRS (Command Query Responsibility Segregation) and event sourcing are frequently discussed together but are independent patterns. You can use either one without the other. Understanding each separately is essential before combining them.

CQRS: Separate Read and Write Models#

Most applications use the same data model for reads and writes. The same orders table serves the API that creates orders and the API that lists them. This works until read and write requirements diverge significantly.