Complex domain modeling
On this page 9 topics
Overview
Topics
- Strategic DDD
- context mapping
- anti-corruption layers
Learn first
4 h of practice (estimate)
Learning outcomes
- Apply strategic DDD: subdomains (core, supporting, generic) and where to invest.
- Build a context map with relationship patterns (partnership, customer–supplier, conformist, published language, open host service).
- Design anti-corruption layers for legacy and third-party systems.
- Run collaborative modeling sessions (event storming) with domain experts across teams.
Lessons
Lab and exercises
Lab
SRA-003-LAB1 · Marketplace domains
Outcomes: 1–4 · Time: ~2 h
- Plan and run an event-storming session on the seller marketplace with role-played domain experts (seller operations, finance, support, trust and safety).
- Produce the event wall: events, commands, actors, policies, and hot spots.
- Classify subdomains as core, supporting, or generic and note build/buy implications for each.
- Draw the context map with named relationship patterns, marking where an anti-corruption layer is needed.
- Compare the map with the current team structure and note mismatches.
Acceptance: build/buy implications noted per subdomain.
Exercises (case-based; six exercises)
| ID | Outcome | Task |
|---|---|---|
| SRA-003-EX01 | 1 | Classify eight Commerce 2030 subdomains as core, supporting, or generic with one-line reasoning each. |
| SRA-003-EX02 | 1 | Argue why tax calculation should not get the best engineers; state when your answer would change. |
| SRA-003-EX03 | 2 | Given a description of six contexts and their interactions, draw the context map and name each relationship pattern. |
| SRA-003-EX04 | 2 | Find a context map that copies the org chart; show two places where the real domain boundary differs and what you would change. |
| SRA-003-EX05 | 3 | Design an anti-corruption layer for a legacy inventory system: interface, translation, error handling, and tests. |
| SRA-003-EX06 | 4 | Write a facilitation plan for an event storm with twenty participants: invitees, scope, agenda, output, and how disagreements are handled. |
Show solutions
- EX01 Example: seller trust scoring and marketplace ranking are core; onboarding workflow, returns handling supporting; payments, tax, email, identity generic. Justify by "what do customers choose us for".
- EX02 Tax is generic and well covered by specialist vendors; building it diverts the best engineers from the core. It changes if the group operates in a jurisdiction no vendor serves or tax is the differentiator.
- EX03 Name each pair: partnership, customer–supplier, conformist, open host service with published language; include direction of influence.
- EX04 Look for contexts split by team where the vocabulary is the same, or contexts merged where it differs; propose a boundary change or a team interaction change.
- EX05 A domain-facing interface; an adapter translating legacy codes and units; timeouts, retries, and a fallback for unknown values; contract tests with recorded legacy responses.
- EX06 Invite experts and each touching team; scope one process end to end; agenda: events, order, commands, hot spots, boundaries; output: wall photo, open-questions list with owners; disagreements recorded as hot spots, not settled by volume.
Outcome 2 is also covered by the lab context map; outcome 4 by EX06 and the lab session.
Workplace evidence: a context map or modeling session that changed team or service boundaries.
Quiz
Outcomes: O1 strategic DDD and subdomains · O2 context maps · O3 anti-corruption layers · O4 collaborative modeling.
A self-check for you: nothing is graded, saved or sent anywhere. Choose an answer, then check it. You can try again as often as you like.
Practical part
Six case exercises SRA-003-EX01 to EX06 plus the lab, defended as a context map to role-played domain experts. Pass: at least five of six exercises correct, quiz at least 8/10, and a context map with a subdomain classification and build/buy note for each subdomain.
Common mistakes
Treating every subdomain as core; context maps that mirror the org chart without examining it.
Assessment
Context map defense.
Workplace evidence
A context map or modeling session that changed team or service boundaries.
Career relevance
Cross-domain systems (STF-006) and enterprise integration (ARC-009).