# Master the Tableau Data Model & Relationships featuring Kirk Munroe

> This is content from just-tim, the data-and-analytics channel by Tim Ngwena (formerly 'Tableau Tim'). Tim has 12+ years of hands-on BI experience and covers Tableau most of all, plus Power BI, Looker, Hex, SQL and data modelling, the analytics industry, and the craft of doing the job — always tool-agnostic and honest about the trade-offs.

- **Author:** Tim Ngwena (just-tim, https://just-tim.com/about)
- **Published:** 2025-05-27
- **Format:** Video · 87 min watch · transcript available
- **Topics:** Data visualisation, Data prep, Analytics
- **Tools:** Tableau (calculated fields, data modelling, extracts, join calculation, joins, multi fact relationships, performance, relationships, unions)
- **Canonical:** https://just-tim.com/posts/master-the-tableau-data-model--relationships-featuring-kirk-munroe
- **Watch:** https://www.youtube.com/watch?v=OE25-cK2ZHI

I sit down with Kirk Munroe for a full masterclass on the Tableau data model, using the Bookshop dataset to build relationships from scratch. We cover logical versus physical tables, base tables, joins, unions, performance options, extract storage, and how multi-fact relationships change the way you structure a model.

## Key takeaways

- Relationships form a logical model you can build without writing SQL, while joins and unions sit at the physical layer inside a logical table and combine before any question is asked.
- Only convert a relationship to a physical join when both tables share the same number of rows at the same grain, so Tableau doesn't needlessly join at runtime.
- Leave the relationship performance options at default unless you hit performance issues, as overriding Tableau's heuristics restricts the questions you can answer.
- Layout is just a visual representation, but with more than one fact table you should make each fact table a base table to use multi-fact relationships and compare unrelated data through shared dimensions.
- Use COUNT of rows from a table rather than COUNTD on a dimension to confirm uniqueness and get the same answer with a far lighter calculation.

## Chapters

- 1:08 Where the data model lives
- 2:46 Relationships and the logical model
- 6:05 Know your data first
- 7:47 Understanding base tables
- 9:46 Relating on multiple fields
- 11:22 Unioning the sales data
- 14:45 Logical versus physical tables
- 17:14 Joins and join calculations
- 22:36 Naming tables and sources
- 23:33 Finishing the model
- 25:00 Relationship performance options
- 29:51 Layout, star schemas and base tables

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/master-the-tableau-data-model--relationships-featuring-kirk-munroe

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just-tim — Data and analytics, with a point of view. · https://www.youtube.com/channel/UC7HYxRWmaNlJux-X7rNLZyw · https://twitter.com/TableauTim · https://www.linkedin.com/in/timngwena