Prior to 2020.2, Tableau had a physical data model that allowed joins between tables. This layer is still present, and it is similar to Power BI’s merge capability within Power Query to join multiple tables into a single table.
With the introduction of the logical model in Tableau 2020.2, a single logical table may consist of one or more physical tables. Two or more logical tables may be related to each other. This approach shares many similarities with Microsoft’s tabular model, but there are currently some core differences that may impact how you approach data modeling in one tool versus another. It’s not always going to be a straightforward scenario to apply knowledge of how to build a data model in one product to building it in the other.
NOTE: This post considers some core differences between Tableau and Power BI modeling as of June 2020. It does not go into detail on announced roadmap features such as Power BI’s enhanced composite models coming later in 2020, which will allow scenarios like combining a “live connection” composite model with additional data sources, or even multiple live connection models.
Read on for four differences David has found.