A model change isn't done when the files are saved. It's done when Desktop has refreshed and the numbers still add up.
with Elizabeth Cecilia. About 10 minutes.
1
Saved isn't finished
The model is in Import mode. It holds a copy of the data, made at the last refresh. So when a change adds or alters a table or column, the saved files describe the new shape, but the copy in memory is still the old one until Desktop refreshes (Home > Refresh).
Check a visual before that, and any measure reading the new column returns blank. It looks like a bug in the measure. It isn't.
A change adds a column to the register. You open the report and every information tooltip is blank. What's most likely?
Answer the question above to unlock this.
After the refresh, reconcile. Click the table that lost a row between layers.
Table
Bronze
Silver
Gold
The gold counts are the real ones. The missing row is planted for the exercise.
2
Let a script do the checking
Counting by eye works for six tables. It doesn't work for 219 measures and seven report pages. The project has a validator script that runs after every change, and it now makes 1,533 checks. A few of the kinds:
Every field a visual names exists in the model
Every visual has the same shape as its hand-made example
Every information button sits in a group with exactly one tile
Each check is proven by breaking a copy on purpose and watching it fail
When it found two subtitles pointing at measures that didn't exist, the fix was the two measures and a new kind of check, so the same gap can't come back unnoticed.
0 / 3
Gold has 143 rows where silver has 144. Where do you look first?
The validator passes, but you haven't opened the report since the change. Done?
A check fails on something you're sure is fine. What do you do?
The ruleRefresh after any change to a table or column. Then reconcile counts layer by layer and run the checks, before you trust a single visual.
Everything is free on GitHub. Open the report next to the lessons and check each step for yourself.
The whole project
The Power BI project, the seed project, the specs and the tools: the whole kit. On the GitHub page, click the green Code button, then Download ZIP, and unzip it anywhere.
The Critical Raw Materials Intelligence report as a single .pbix file to open in Power BI Desktop. Open the latest release under Releases, then Assets, on the right of the GitHub page.