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Domain-Driven Design Distilled
AI Software Development

Domain-Driven Design Distilled

Vaughn Vernon 2016 10 references

Apply Domain-Driven Design patterns for strategic design (Bounded Contexts, Ubiquitous Language, Subdomains, Context Mapping) and tactical design (Aggregates, Domain Events) when architecting or reviewing software systems.

domain-driven-design bounded-contexts aggregates ubiquitous-language event-sourcing software-architecture

Overview

The Core Framework

  • Design is inevitable — choose intentional design (DDD) over accidental design (Big Ball of Mud)
  • Strategic design (boundaries, language, integration) must precede tactical design (Aggregates, Domain Events)
  • A Bounded Context is a semantic boundary; the Ubiquitous Language within it IS the design artifact
  • Default to eventual consistency between Aggregates; immediate consistency is the exception
  • Knowledge acquisition through Domain Expert collaboration is the engine, not documentation or process

Quick Lookup

Situation Do This Avoid This
Starting a new system Identify Core Domain and Bounded Contexts first Jumping to database schema or Aggregate design
Multiple meanings for same term Create separate Bounded Contexts Forcing one abstract model to cover all meanings
Integrating with legacy/external Use Anticorruption Layer + messaging Importing their types or synchronous RPC chains
Designing data consistency Ask Domain Experts about time tolerances Defaulting to immediate consistency everywhere
Modeling domain objects Embed business logic in domain objects Getters/setters only (Anemic Domain Model)
Discovering domain structure Run Event Storming: Events → Commands → Aggregates Starting from database tables or API endpoints
Sizing Aggregates Start small (one Entity); grow only for invariants Large Aggregates "for convenience"
Cross-Aggregate updates Publish Domain Events for eventual consistency Modifying multiple Aggregates in one transaction

The Key Insight

"You really cannot apply tactical design in an effective way unless you begin with strategic design." — Vaughn Vernon, Chapter 1

References

1

Aggregate Design Rules

An Aggregate is a boundary drawn around exactly those Entities and Value Objects that must be consistent when a transaction commits, as determined by…

5
aggregates transactional-consistency entities +2
CRITICAL
2

Anti-Patterns and Failure Modes

DDD defines failure modes as explicitly as it defines patterns. Each anti-pattern has a specific causal chain explaining how teams arrive there and…

1-5
anti-patterns big-ball-of-mud anemic-domain-model +1
HIGH
3

Bounded Contexts and Ubiquitous Language

A Bounded Context is a semantic boundary within which each software model component has a specific meaning. The Ubiquitous Language is the rigorous…

2
bounded-context ubiquitous-language semantic-boundary +1
CRITICAL
4

Context Mapping Relationships

Context Mapping defines the relationships and integration patterns between Bounded Contexts. The mapping types encode political relationships between…

4
context-mapping integration anticorruption-layer +2
CRITICAL
5

The Core Framework: Strategic Before Tactical

DDD rests on one causal claim: design is inevitable, and only intentional design produces competitive advantage. Strategic design (Bounded Contexts,…

1-2
strategic-design effective-design ddd-overview
CRITICAL
6

Domain Events and Event Sourcing

A Domain Event is a record of a business-significant occurrence, named as a past-tense verb (e.g., ProductCreated). The fundamental distinction: a…

6
domain-events event-sourcing eventual-consistency +2
HIGH
7

Event Storming

Event Storming (Alberto Brandolini) is a rapid, tactile, collaborative design technique that encodes a critical sequencing insight: Domain Events…

7
event-storming collaborative-modeling discovery +1
HIGH
8

Implementation Playbook

DDD adoption follows a specific sequence: strategic design first, tactical design second, with Event Storming as the bridge between them. Skipping or…

1-7
implementation adoption sequencing +2
HIGH
9

Rules of Thumb

Collected heuristics from across the book — actionable guidelines for DDD practitioners.

1-7
heuristics guidelines quick-reference
HIGH
10

Strategic Subdomain Classification

Subdomains decompose a business domain into three categories that determine where to concentrate scarce modeling effort and talent:

3
subdomains core-domain investment-strategy +1
HIGH