“Storage is scarce.” – That was once true. Relational databases, with their strict principle of no redundancy and full normalization, were born in that era. To this day, the relational database is often the default solution in many projects—mainly because that’s how we were taught.

But this frugality comes at a cost: we only store the current state. History and changes disappear, traceability becomes difficult, and complex queries impact performance.

There’s another way: Event Sourcing and CQRS turn the tables. Instead of just persisting the current state, every change is stored as an event. Read models can be tailored specifically for performance and comprehensibility. The result: transparent history, fast queries, and more flexible architectures.

In this talk, we provide a hands-on introduction to Event Sourcing and CQRS. We’ll cover the core principles and then dive into a concrete .NET implementation—without relying on complex or heavyweight frameworks.