Domain-Driven Design Europe 2017
http://dddeurope.com - https://twitter.com/ddd_eu

If (domain logic) then CQRS, or Saga?

The “if” statement – the guard clause that makes sure that what shouldn’t happen, can’t happen. We see it all over our code base, especially in our domain logic. The thing is, when we use properties of domain objects in those if-statements, we don’t even realize that other agents may have just changed that data – or will change it just a second later. In essence, hiding behind those little “ifs”, are all kinds of race conditions and collaborative domains – the places where CQRS approaches are necessary. Join Udi for a different perspective on domain logic, CQRS, and long-running processes. It will be quite a saga.


Udi Dahan is one of the world’s foremost experts on Service-Oriented Architecture and Domain-Driven Design and also the creator of NServiceBus, the most popular service bus for .NET.