Aggregate

Definitions

1. A cluster of domain objects (entities and value objects) that are treated as a single unit for data changes. The aggregate root is the only entry point — external objects can only hold references to the root, not internal objects. All invariants within an aggregate are enforced in a single transaction. Keep aggregates small.

   In plain English: A group of related objects that change together and are protected by a single gatekeeper object.

   Example: "The Order aggregate contains OrderLines and the ShippingAddress — all changes go through the Order root, which enforces the 'minimum order value' rule."

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