Summary
This chapter covered the first part of implementing DDD. We've explored the domain layer building blocks and understood their design and implementation practices using ABP Framework.
The aggregate is the most fundamental DDD building block, and the way we change an aggregate's state is very important and needs care. An aggregate should preserve its validity and consistency by implementing business rules. It is essential to draw aggregate boundaries correctly.
On the other hand, domain services are useful for implementing the domain logic that touches multiple aggregates or external services. They work with the domain objects, not DTOs.
The repository pattern abstracts the data access logic and provides an easy-to-use interface to other services in the domain and application layers. It is important not to leak your business logic into repositories. The specification pattern is a way to encapsulate data filtering logic. You can reuse and combine them when you...