Training Agenda

CQRS &
Event Sourcing

CQRS separates the write model from the read model — allowing each to be optimized independently. Event Sourcing takes it further: instead of storing current state, every change is stored as an immutable event, making the full history of what happened auditable and replayable. Together they enable audit logs without bolting them on, temporal queries without extra infrastructure, and read models rebuilt at will. This training covers both patterns deeply, with Spring Boot implementation examples and an honest look at the complexity they introduce.

1–2 days On-site, remote, or hybrid Up to 20 participants German or English
What We Cover
Separate reads from writes, store events not state
Day 1

CQRS Fundamentals & Read Model Design

  • CQRS core concept: separate command and query responsibilities
  • Command model: aggregates, command handlers, invariant enforcement
  • Query model: optimized read projections — denormalized, materialized
  • Synchronization patterns: synchronous vs eventual consistency between models
  • When CQRS pays off — and when it's over-engineering
  • Read model storage: relational projections, Elasticsearch, Redis
  • Projection rebuilding: replaying events to regenerate read models
  • CQRS with Spring Boot: command bus, query bus, event bus patterns
  • Axon Framework: built-in CQRS and Event Sourcing support
  • Testing CQRS: command handling tests, projection tests
Day 2

Event Sourcing in Depth

  • Event Sourcing fundamentals: append-only event store, no mutable state
  • Event store options: EventStoreDB, Axon Server, PostgreSQL-based
  • Aggregate design with Event Sourcing: apply() methods, rehydration from events
  • Snapshots: reducing rehydration time for high-event-count aggregates
  • Event versioning: upcasting old events to new schemas
  • Temporal queries: reconstructing state at any point in time
  • Sagas with Event Sourcing: long-running processes using event-driven state machines
  • CQRS + Event Sourcing together: the full pattern, end to end
  • Operational concerns: storage growth, event retention, GDPR and right-to-erasure
  • When NOT to use Event Sourcing: the honest trade-off analysis
Learning Outcomes
What your team walks away with

Developers and architects who understand CQRS and Event Sourcing deeply enough to apply them where they genuinely help — and recognize when simpler patterns suffice.

Book the CQRS & Event Sourcing training

Best delivered after foundational DDD knowledge. Can be combined with the Domain-Driven Design training for a complete 3-day architectural patterns track.

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