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Aggregate Root

The entry point entity for an aggregate. All external references must go through the root—no direct access to internal entities.

In Angzarr​

  • Called root in the Cover structure
  • Always a UUID (not a domain-specific ID like order_id)
  • Combined with domain name forms the unique identity: {domain}:{root_id}

Example: An order aggregate has root ID 550e8400-e29b-41d4-a716-446655440000. Its full identity is order:550e8400-e29b-41d4-a716-446655440000.

DDD Relationship​

The aggregate root is standard DDD terminology. From Evans:

  • A cluster of domain objects treated as a single unit for data changes
  • External entities can only hold references to the root
  • The root controls access to internals and enforces invariants

The root ID is stable for the lifetime of the aggregate. Events reference the root ID in their Cover, enabling event sourcing and replay.