- Using Aggregates in the Scrum Core Domain
- Rule: Model True Invariants in Consistency Boundaries
- Rule: Design Small Aggregates
- Rule: Reference Other Aggregates by Identity
- Rule: Use Eventual Consistency Outside the Boundary
- Reasons to Break the Rules
- Gaining Insight through Discovery
We’ve examined how crucial it is to follow the Aggregate Rules of Thumb when designing Aggregates.
- You experienced the negative consequences of modeling large-cluster Aggregates.
- You learned to model true invariants in consistency boundaries.
- You considered the advantages of designing small Aggregates.
- You now know why you should favor referencing other Aggregates by identity.
- You discovered the importance of using eventual consistency outside the Aggregate boundary.
- You saw various implementation techniques, including how you might use Tell, Don’t Ask and Law of Demeter.
If we adhere to the rules, we’ll have consistency where necessary and support optimally performing and highly scalable systems, all while capturing the Ubiquitous Language of our business domain in a carefully crafted model.