cqrs

name	cqrs
description	CQRS command query responsibility segregation. Use for complex domains.

CQRS (Command Query Responsibility Segregation)

CQRS is a pattern that separates read and update operations for a data store. Instead of using a single model for both, you have a Command Model (Write) and a Query Model (Read).

When to Use

• High Disparity: Read load is 1000x higher than Write load (or vice versa).
• Complex UI: The UI needs data shaped differently than the way it's stored (e.g., Dashboard aggregation).
• Event Sourcing: CQRS is almost mandatory for Event Sourcing.

Quick Start (Conceptual)

// Command Side (Write) - Optimized for Integrity
class CreateOrderCommand { ... }
class OrderAggregate {
    create(cmd: CreateOrderCommand) {
        // Validate business rules
        // Save to DB (Normalized / Event Store)
    }
}

// Query Side (Read) - Optimized for Speed
class GetOrderSummaryQuery { ... }
class OrderSummaryProjector {
    // Listens to "OrderCreated" event
    on(event) {
        // Update a flat "Read DB" (e.g., ElasticSearch, Redis, Document DB)
        
    }
}