Opening relationships to join at the physical layer through database joins

Before Tableau released the relationships feature, the only way to expand your analysis to use additional fields from a secondary table in Tableau was to create a join at the physical layer of the data.

Although relationships are the preferred method of combining tables to get additional fields, joins still have their use cases.

Cases where you might use joins are as follows:

• When you know you are only supporting one use case in the Tableau workbook(s) that uses the model
• When you want to filter data through your join
• When you need to use an entity table for row-level security
• When you are making a geospatial join

Let’s start by exploring the first two use cases, supporting a single use case and using the join for data filtering.

Single use case and using the join for a filter

When exploring joins in Chapter 8, we looked back to Chapter 4, when we joined the sales...