12. What is Aggregate
•Coherent Business Model
•Command-Aggregate-Event
•Work as State Machines, or
Independent Components
•Come with Biz Rules
•Break the Timeline
•Look for Behavior & Responsibilities
Instead of Data
•Postpone Aggregate Naming
13. ● Protect business invariants inside
Aggregate boundaries
● Design small Aggregates
● Reference other Aggregates by
identity only
● Update other Aggregates using
eventual consistency
Aggregate Rules of Thumb
15. 不變條件 Invariants
Invariants are generally
business rules / enforcements /
requirements that you impose
to maintain the integrity of an
object at any given time.
- Integrity(validity)
- Consistency