Domain-driven design (DDD) advocates modeling based on the reality of business as relevant to your use cases. In the context of building applications, DDD talks about problems as domains. It describes independent problem areas as Bounded Contexts (each Bounded Context correlates to a microservice), and emphasizes a common language to talk about these problems. It also suggests many technical concepts and patterns, like domain entities with rich models (no anemic-domain model), value objects, aggregates, and aggregate root (or root entity) rules to support the internal implementation. This section introduces the design and implementation of those internal patterns.
Dependencies in a DDD Service, the Application layer depends on Domain and Infrastructure, and Infrastructure depends on Domain, but Domain doesn't depend on any layer. This layer design should be independent for each microservice. As noted earlier, you can implement the most complex microservices following DDD patterns, while implementing simpler data-driven microservices (simple CRUD in a single layer) in a simpler way.
Software design thought leader and founder of Domain Language, Eric Evans, provides a systematic approach to domain-driven design, presenting an extensive set of design best practices, experience-based techniques, and fundamental principles that facilitate the development of software projects facing complex domains. Intertwining system design and development practice, this book incorporates numerous examples based on actual projects to illustrate the application of domain-driven design to real-world software modeling and development.
Leading software designers have recognized domain modeling and design as critical topics for at least twenty years, yet surprisingly little has been written about what needs to be done or how to do it. Although it has never been clearly formulated, a philosophy has developed as an undercurrent in the object community, which I call \"domain-driven design\".
Domain-Driven Design fillsthat need. This is not a book about specific technologies. Itoffers readers a systematic approach to domain-driven design,presenting an extensive set of design best practices,experience-based techniques, and fundamental principles thatfacilitate the development of software projects facing complexdomains. Intertwining design and development practice, this bookincorporates numerous examples based on actual projects toillustrate the application of domain-driven design to real-worldsoftware development.