Relate the two tables

Relate the two tables — guided practice

Create and test one-to-many filter propagation.

Use free Power BI Desktop on a supported 64-bit Windows computer; check the linked current system requirements and installation policy. No cloud sign-in, subscription or publishing is needed. Save sessions.csv and sites.csv in one stable practice folder. Sessions are S1 N Jan 15 8/10; S2 S Jan 15 6/10; S3 N Feb 15 7/10; S4 S Feb 15 5/10; S5 N Mar 15 4/10; S6 S Mar 15 9/10 (all dates 2026; values attended/capacity). Sites: N=North, S=South. Follow lessons cumulatively and save report.pbix locally. Menu/pane labels can vary slightly with monthly releases; use the named feature.

1. 1. Inspect the model

   Open Model view. If an automatic relationship exists, inspect it rather than adding a duplicate.

   You should see: There should be one Sites-to-Sessions link on site_id.

   Automatic suggestions require confirmation.

2. 2. Set the relationship

   Use Manage relationships/New or edit the existing link: Sites[site_id] 1 to Sessions[site_id] many, active, single direction from Sites to Sessions.

   You should see: Sites is the one side; Sessions is the many side.

   N/S occur once in Sites and repeatedly in Sessions.

3. 3. Build a verification table

   In Report view add a Table visual with Sites[site_name] and Sum of Sessions[attended].

   You should see: North 19 and South 20; total 39.

   A simple visual tests the relationship before design work.

4. 4. Diagnose a wrong result

   If each site shows 39, inspect the active relationship and chosen columns; restore the intended link.

   You should see: Each row displays only its matching sessions.

   Repeated grand totals often indicate missing filter propagation.