Modeling

This page is a task-oriented overview of modeling in DDDesigner. For DDD concepts in depth, use the Practical DDD guide.

Context Map

Start with strategic design:

1. Open Context Map.
2. Add Bounded Contexts.
3. Draw relationships (for example Partnership, Customer–Supplier, Conformist, Anti-Corruption Layer).
4. Keep names aligned with the Ubiquitous Language of each context.

Aggregates

On the Aggregates canvas:

1. Create an Aggregate and its root.
2. Add commands, domain events, entities, and value objects as needed.
3. Declare invariants on the aggregate or value objects.
4. Link commands to the events they emit.

Use Event Storming first when the flow is still unclear; then promote sticky findings into Aggregates.

Projections (read models)

On Projections:

1. Create a projection for a screen or query.
2. Add attributes (field names and types).
3. Add handlers and map updates such as order_id = event.order_id.
4. Attributes alone do not define sources — handlers do.

Optional Read model storage → Postgres requires Chronacta event-store codegen. Details live in the Chronacta materials; keep the default storage until you intentionally opt in.

Check model quality

Before generation or sharing:

1. Open diagnostics / Model Health.
2. Fix blocking errors (missing names, broken references, invalid versions).
3. Treat warnings as design debt to clear when you can.

The in-app ? help explains the current canvas view without leaving the editor.

Next steps

• Code generation — choose a stack and generate
• Working with AI — let an assistant propose model changes
• DDD guide — Event Storming, Sagas, Business Actions, and examples