CQRS

Definitions

1. Command Query Responsibility Segregation — separating the read model (queries/views) from the write model (commands/mutations). Commands validate and modify state; queries return data from optimized read stores. Enables independent scaling (reads vs writes), specialized storage (normalized writes, denormalized reads), and complex domain logic without compromising query performance.

   In plain English: Using different models for reading and writing data, so each can be optimized independently.

   Example: "The write side uses a normalized PostgreSQL schema with strict validation. The read side uses a denormalized Elasticsearch index optimized for search and filtering."

Related Terms

• Webhook vs. Polling
• Event-Driven Architecture
• State Machine
• Strangler Fig Pattern
• Event Sourcing
• Hexagonal Architecture
• API Gateway Pattern
• Pub/Sub