Data structures and meaning
Crow's-foot ERD
Entities with attribute compartments and crow's-foot cardinality marks at the line ends — the working ERD idiom.
erd.crowfoot@1New DDN source
Why use it?
The crow's-foot end reads at a glance: one, many, optional — three marks answer most modelling questions.
When it helps
Logical data modelling sessions where the schema is being agreed in the room.
How to read it
- Each box is an entity with its attributes; the end marks read (optionality, cardinality) outward from the entity.
- Read a relationship both directions — each end is a separate claim.
What you need
- The entities and attributes
- The relationships
- Optionality and cardinality per end
Things to check
- Do not mark both ends many without asking where the join entity went.
- An attribute everyone updates together is usually an entity in disguise.
Scope of this diagram
Declared ERD with cardinality-mark validation; physical naming and types come later.
Work with the converted example
- Open the viewer and select
erd. Inspect the rendered view and its source. - Open the designer. Keep the selected profile and inspect its legal palette and property controls.
- Change one displayed title or an appropriate data value. Apply the edit and check the resulting diagram.
- Run the verifier and review its diagnostics before moving complete content into review.
- Download your edited DDN source to retain the change.
The example uses the indentation-based ddn-next-1 dialect. The language guide explains reusable definitions, dotted data rows and explicit property blocks.