Aggregate

Kind: pattern

Layer: Domain Modeling

Record: architecture:aggregate

Severity: contextual

Scope: domain, consistency boundary, bounded context

Canonical: Ontology

A design pattern that groups entities under one root, which is the only entry point and keeps the group's invariants.

Listed in Architecture principles, after Explicit Boundaries and before Value Object.

Requires

• Explicit Boundaries

Reinforces

• Invariant
• Encapsulation

Enables

• Transactional Consistency Boundary
• Root-Guarded Invariants

Conflicts with

• Anemic Domain Model

In tension with

• Aggregate Size
• Domain Service
• Domain Service / Aggregate

Tensions

• Aggregate / Aggregate Size

Violated by

• Anemic Domain Model

Refactored by

• Add Aggregate Invariant

Severity

• contextual

Category

• Domain Architecture

Refactors

• Domain-Driven Design
• Domain Model

Linked from

• Anti-patterns
• Domain Architecture
• Contracts / Interfaces / Compatibility
• Core Modular Design
• Domain Architecture
• Severity levels
• The resolutions