ddd-aggregate

One-line summary

An aggregate is a cluster of entities and value objects treated as a single unit for data changes — a transactional consistency boundary with one root entity that owns it.

When to use this skill

• Deciding which entities belong together as one unit.
• Choosing between "one big object" and "several related objects".
• Reference rules: "can Order hold a Customer object, or just a customerId?".
• Performance and locking concerns that trace back to aggregate size.

When NOT to use this skill

• Within a single entity's behavior — that is ddd-entity territory.
• Cross-context relationships → ddd-context-mapping.
• Eventual consistency across aggregates via events → ddd-domain-event.

Core content