This chapter covers, for junior engineers, the basic notation of an ER diagram (Entity-Relationship Diagram) — entities, attributes, relationships, and cardinality — the steps for building an ER diagram from business requirements, and the major tools (mermaid / draw.io / PlantUML).
A workshop format where business people and developers stand at the same wall and lay out the flow of the business on sticky notes to find the domain model. Covers the grammar of the notes, the granularities from Big Picture to Design-Level, the phases of running one, and how the notes map onto value objects, aggregates, and use cases, using an e-commerce order as the example. It also touches on Domain Storytelling, which draws the business as a story.