Tactical DDD

Confirm the bounded context and ubiquitous language before choosing tactical patterns. Model behavior and invariants, not a database diagram with domain names.

Workflow

1. Collect commands, policies, invariants, lifecycle, and failure cases from domain examples.
2. Identify identity-bearing concepts and immutable descriptive values.
3. Draw candidate consistency boundaries.
4. Choose an aggregate root that guards each boundary.
5. Keep cross-aggregate references by identity and coordinate across them at the application/process level.
6. Place behavior where the knowledge lives; use a domain service only when no entity/value object naturally owns it.
7. Define repository interfaces around aggregate persistence needs, not tables.
8. Emit domain events for facts other parts of the model need to react to.
9. Test invariants and state transitions without infrastructure.

Building Blocks