Projects and development teams are struggling with poorly designed systems, with many developers dedicated to patching systems just to keep them alive. Largely the software development culture is broken, Vaughn Vernon claimed in his presentation at the Domain-Driven Design Europe conference earlier this year, talking about problems he has encountered but also about solutions to these problems.
Eric Evans' talk at QCon London prescribed Domain Driven Design as a mechanism to successfully handle the "big ball of mud" that can emerge as multiple teams attempt to integrate services from external teams.
Microservices and Domain-Driven Design (DDD) are not only about Bounded contexts, although a fundamental tool for defining granularity of microservices there are other important concepts as well. Correspondingly DDD is just not about entities and repositories, Michael Plöd claimed in his presentation at the recent microXchg conference in Berlin showing how DDD can be used creating microservices.
User Story Mapping can be a simple yet valuable pattern when adopting Domain-Driven Design (DDD) in projects dealing with complex domains. It can help creating shared domain knowledge among developers and domain experts, Eriksen Costa claims in a blog post discussing advantages combining User Story Mapping with Domain-Driven Design (DDD).
Moving from a monolith to microservices the only value business stakeholders care about is reducing cost. It will not increase or protect revenue and neither scaling nor distribution are good reasons that will convince the business, Ian Cooper claimed in his presentation at this year’s Microservices Conference in London describing guidelines moving from a monolith to a microservices architecture.
Eventual consistency is a design approach for improving scalability and performance. Domain events, a tactical element in Domain-Driven Design (DDD), can help in facilitating eventual consistency, Florin Preda and Mike Mogosanu writes in separate blog posts, each describing the advantages achievable.
Command Query Responsibility Segregation (CQRS) is the starting point of a change that will have a profound impact on system architecture, Dino Esposito claims in three articles in MSDN Magazine. It’s the first step in an evolution transitioning software architects from the idea of “models-to-persist” to the idea of “events-to-log” and about event-based data instead of data snapshots.
After failing with two proof of concept, mainly with scalability issues, when trying to renew their main website the business decided to take a more agile and incremental approach and in a restart of the project inspired by Domain-Driven Design (DDD) having developers talk with domain experts, Chris Patuzzo explains describing the principles of DDD in the context of a real project.
Not interacting with domain experts is one of a common set of mistakes done when using Domain-Driven Design (DDD), finding and correcting them early on may save a team time, Daniel Whittaker claims describing ten mistakes he regularly see developers do.
Reuse has been a watch word for almost everything that has happened in system development during the last thirty years, but reuse is like cyanide; in really small portions it can be healthy, using it too much it starts doing a lot of damage, Udi Dahan claimed in his presentation giving a different perspective on business logic at this year’s DDD Exchange conference in London.
Creating and working with well-designed aggregates is one of the least well understood tactical patterns found in Domain-Driven Design, Vaughn Vernon explains in two articles giving some guidelines to composing aggregate boundaries and alternatives to an ORM when storing them.
Bounded Context concept from Domain Driven Design (DDD) can be used to divide a large model into smaller models using the Database Context (DbContext class) in Entity Framework (EF). Bounded Context creates smaller, more cohesive models with boundaries between models.
Greg Young, the lead architect behind the Event Store, recently talked about the Projections Library in the Event Store and how it can be used as a Read Model. In his presentation Greg explained what the Projections Library is, together with its main use cases. He also presented a number of examples of practical use.
Apache has released Apache Isis, a Java framework for rapidly developing domain-driven applications. Users focus on developing domain objects and Apache Isis takes care of persistence, security and the user interface. Apache Isis became an Apache top-level project in October 2012 and version 1.0 was released on December 2012.
The Patterns and Practices team at MSDN recently announced a CQRS Journey Guidance project – the project walks through building a fictional Contoso Conference Management System using DDD, CQRS and Event Sourcing.