When to use a data model, joins, or blends
In one sense, every data source you create using the latest versions of Tableau will use a data model. Even data sources using one physical table will have a corresponding object in the logical layer of a data model. But when should you relate tables using the data model, when should you join them together in the physical layer, and when should you employ blending?
Most of the time, there's no single right or wrong answer. However, here are some general guidelines to help you think through when it's appropriate to use a given approach.
In general, use a data model to relate tables:
- When joins would make correct aggregations impossible or require complex LOD expressions to get accurate results
- When joins would result in the duplication of data
- When you need flexibility in showing full domains of dimensions versus only values that match across relationships
- When you are uncertain of a data...
