Power BI Data Modeling, Explained

An interactive, single-file visual aid for teaching the three concepts that trip up almost everyone learning the Power BI / Power Pivot Data Model:

1. Cardinality — pick a row on the "one" side and watch the matching rows light up on the "many" side. Switch between one-to-one, one-to-many, and many-to-many (which reveals a bridge table).
2. Filter direction — click a region in users and watch a filter pulse travel down the relationship arrow into orders, recomputing Total Sales. Selecting from the orders side shows that nothing flows back — until you flip the both-directions toggle.
3. Filter context — a mini pivot where every cell is a filter context. Move the slicer and watch cells recompute, while a CALCULATE(…, ALL()) measure refuses to budge.

Built to pair with the data-modeling chapter of Modern Data Analytics in Excel — same users / orders star schema, joined on Region.

Use it

Open index.html in any browser. No build step, no dependencies, nothing to install — it's one self-contained HTML file. Works great projected in a classroom, and is ready to publish on GitHub Pages.

Inspired in spirit by Garrick Aden-Buie's tidyexplain animations.

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