As I explained in a previous post, Domain-driven Design (DDD) is a design principle I strongly believe in.
With more and more evidence of systems/companies switching to NoSQL for scalability reasons, creating a rich domain model becomes less and less of an option if you don’t want to shoot yourself in the foot. Indeed, while traditional applications sometimes often rely on the database to enforce integrity and referential constraints, this is no longer an option with NoSQL because of the CAP theorem.
So, this means enforcing constraints becomes the sole application’s responsibility, which is, IMHO, a good thing. Validation naturally belongs to the domain layer, and once you go through the trouble of transforming your POJOs/anaemic domain model into a rich domain model, you will certainly start adopting more and more DDD principles.
Responsibilities thus become clear : the storage layer handles the (possibly distributed) persistence, and the domain layer handles the domain-specific business rules and validation.
