Domain-Driven Design (DDD) is a software development approach that focuses on modeling software to match a complex business domain. It emphasizes collaboration between technical and domain experts to create software that reflects the complexities and nuances of the domain. This approach is particularly beneficial in complex domains where the business logic and rules are intricate and evolving.
- Ubiquitous Language: A common language used by developers and domain experts. This ensures that all parties have a shared understanding of the domain.
- Entities: Objects that are defined by their identity, rather than their attributes. They are often key functional elements in the domain.
- Value Objects: Objects that are defined by their attributes and do not have a conceptual identity. They are often used to describe aspects of the domain.
- Aggregates: A cluster of domain objects (entities and value objects) that are treated as a single unit for data changes. Each aggregate has a root and a boundary.
- Repositories: Mechanisms for encapsulating storage, retrieval, and search behavior, which emulates a collection of domain objects.
- Domain Events: Events that signify a state change in the domain model, often used to trigger side effects in other parts of the system.
- Services: When an operation does not conceptually belong to any entity or value object, these operations are defined in domain services.
- Layered Architecture: DDD often uses a layered architecture, separating concerns into layers like UI, Application, Domain, and Infrastructure.
- Microservices: DDD can be used in designing microservices, where each microservice tackles a specific domain or subdomain.