Transitioning from DB-Centric Development to DDD: Object-Oriented Principles and Cloud Infrastructure Challenges

In the past, the Database Driven Development approach was a closed design that limited the system's growth potential and took away developers' options. Along with team members, the author applied Domain Driven Design (DDD) in the field, redefining it not as a mere design technique but as an exploratory process for solving problems.

Through Event Storming and Mob Programming, they shared domain knowledge and clarified the Ubiquitous Language and Bounded Context. Through the process of validating hypotheses based on test code and refactoring variable names and method names multiple times, they confirmed that DDD's questions ultimately connect to object-oriented design principles.

Cloud services and the MSA pattern provided clues for separating the domain layer from the infrastructure layer. They selected and applied optimal infrastructure, such as using a mix of MongoDB and MySQL, and through this secured overwhelming performance and stability compared to the legacy system. However, they emphasized that technical pain, such as obstacles during deployment and operations, also accompanied this process, and argued that DDD is an integrative approach that mobilizes all development knowledge.