ddd-tactical-patterns

Design DDD aggregates by grouping entities and value objects around a single root that enforces transactional consistency. The aggregate root validates invariants, ensuring all state changes preserve business rules without leaking domain logic into infrastructure layers.

Value objects in domain-driven design represent immutable, validated concepts identified by their attributes rather than identity. They ensure value-based equality and encapsulate validation rules, reducing accidental complexity when modeling domain concepts.

Define repository contracts for aggregate roots by specifying domain-friendly access patterns that focus persistence operations on the root entity. This keeps infrastructure concerns isolated and ensures data retrieval aligns with aggregate boundaries.

Emit domain events in a bounded context when important state transitions occur within an aggregate. Use meaningful, past-tense event names to communicate these changes, establishing stable boundaries for downstream integration and eventual consistency.

Refactor an anemic service into rich domain behavior by extracting business logic into aggregates and value objects that enforce invariants. Move data manipulation out of services and encapsulate rules within the domain model itself.