CQRS: A Practical Guide to Command Query Responsibility Segregation
Introduction Command Query Responsibility Segregation (CQRS) is an architectural pattern that separates reads (queries) from writes (commands). Rather than using a single data model and layer to both modify and read state, CQRS encourages designing optimized models and pathways for each. This separation can improve scalability, performance, and clarity—especially in complex domains—while introducing new challenges around consistency, messaging, and operational complexity. This guide provides a practical, vendor-neutral overview of CQRS: what it is, when it helps, how to implement it (with and without event sourcing), and the pitfalls to avoid. Code examples are provided to illustrate implementation techniques. ...