Fresh perspective on real-world software design: from DDD to CQRS and from both up to Event Sourcing

Description

Software exists and will exist to make our life easier. To some extent it is acceptable that software introduces new processes and new ways of doing old things. But for the most part software must simply mimic the real world. We’ve been pushing models all the way through for decades now. It worked well for years, but now the classic data modeling approach based on entities, relationships and normalization is showing signs of age. What’s new? The point of the workshop is that we probably missed a key thing: real world has events not models. After a first part in which DDD is introduced and then CQRS is presented to improve over it, both are pushed aside to make room for event sourcing. But event sourcing alone shows only half of its tremendous potential. Event sourcing and CQRS form a really powerful duo for the years to come.

The workshop goes through the definition of the DDD alphabet soup (bounded context, entities, value objects, complex types, and aggregates), compares and contrasts domain models with anemic models and relates a domain model to DTOs, real-world processes, business rules, and concrete technologies for persistence such as Entity Framework Code-first. At the end of the module the growing complexity of an all-encompassing model is clear to everybody and with it the need of stepping back to a simpler model such as CQRS but equally powerful. CQRS, however, opens up a significantly different perspective of application design. In a way, it clears doubts that obfuscated in the past basic patters such as Transaction Script and it also reintroduced through the window anemic models that just were sent off via the door with the advent of deep modeling. A revised demo will just show how natural CQRS can be in the design of an application. Finally, the workshop reaches its climax with event sourcing as a form of lateral thinking. You’ll see a full demo where a NoSQL database stores events, events are replayed into a DDD read model, and issues such as synchronization, consistency, performance, latency arise naturally to call for a solution.

Speaker – Dino Esposito.

Target Audience

Roadmap