Event Sourcing and CQRS: Building Resilient Data Architectures for Modern Distributed Systems
Table of Contents Introduction Core Concepts 2.1. What Is Event Sourcing? 2.2. What Is CQRS? Why Combine Event Sourcing and CQRS? Designing a Resilient Architecture 4.1. Event Store Selection 4.2. Command Side Design 4.3. Query Side Design 4.4. Event Publishing & Messaging Practical Implementation Example 5.1. Domain Model: Order Management 5.2. Command Handlers 5.3. Event Handlers & Projections 5.4. Sample Code (C# with EventStoreDB & MediatR) Operational Concerns 6.1. Event Versioning & Schema Evolution 6.2. Idempotency & Exactly‑Once Processing 6.3. Consistency Models 6.4. Testing Strategies 6.5. Monitoring & Observability Real‑World Case Studies Best‑Practice Checklist Conclusion Resources Introduction Modern distributed systems must cope with high traffic volumes, evolving business rules, and ever‑changing infrastructure. Traditional CRUD‑centric designs often become brittle under these pressures: they mix read and write concerns, hide domain intent, and make scaling unpredictable. ...