Ddd Tactical Patterns

This is for when you're past whiteboarding context maps and need to actually write the domain layer. It walks you through organizing code around aggregates, value objects, and invariants instead of letting everything leak into service classes. The guidance is practical: identify what must stay consistent, draw boundaries at aggregate roots, emit events when state changes matter, and keep repositories thin. The example shows a simple Order with guard clauses protecting its state transitions. It won't help you pick a database or design APIs, but if you're refactoring an anemic model or just want your business rules to live in one defensible place, this keeps you honest about where behavior belongs.