Charts, distributions and measurement
Bar chart — live records, keyed refresh
A data-bound bar chart over a records block: the records are the source, the chart is a projection of them.
chart.basic@1New DDN source
Why use it?
Show that the chart is generated from data you can replace — the supported live-dashboard pattern is a transactional record swap, not an image swap.
When it helps
Any metric over categories where the numbers will change but the model must not.
How to read it
- Bars read value against unit by category.
- The source data block is one summary away in the Files panel.
What you need
- Category keys
- Numeric values with units
- A data block to own them
Things to check
- Do not edit the picture when the data is wrong — edit the records.
- Do not reorder keyed records expecting identities to follow position.
Scope of this diagram
Bounded native marks and finite JavaScript arithmetic; refresh replaces records, never structure.
Work with the converted example
- Open the viewer and select
latency_chart. 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.