Tableau Desktop and Web Authoring Help

Note: For single table data sources or single-base table data sources, all the tables are related. Everything on this page refers to multiple base table data sources.

Field-level relatedness

Data models with multiple base tables have a lot of flexibility in how the tables can relate—or not relate—to each other. The relatedness of the tables is a constant based on the data model. However, the relatedness of fields in a viz depends on what fields are active in that viz (that is, what fields are in use on worksheet shelves as pills). At the level of a single viz, Tableau evaluates active fields in pairs to determine how they relate to each other. Because the way fields interact depends on their status as a dimension or a measure as well as their relatedness, there are different messages for different types of field pairs:

• Unrelated dimension-dimension pairs
• Unrelated dimension-measure pairs
• Unrelated filter pairs

An unrelated icon on a field means it's unrelated to at least one other field in the viz. This icon can appear in a pill on a shelf or in the Data pane. Hovering over the icon opens a tooltip with more information.

When a field is added to the viz, its relatedness is evaluated against the fields currently active in the viz. If an unrelated field is added, Tableau displays a dialog box with information about relatedness and the structure of the visualization. Note that the dialog won't be shown if Don't show this again was selected.

The icon tooltip and the relatedness warning dialog give you information about how the fields that are active in the viz are related to each other at that moment and what impact that will have on how Tableau computes results.

In Tableau, aggregated dimensions—such as ATTR(dimension) or MIN(dimension)—act like measures. The tooltip message and inline alert message for the warning dialog reflect this.

Know your data model

Whenever you're working with a data model that contains multi-fact relationships, it's useful to refer to the model regularly on the Data Source page. The examples in this topic are based on a data model with two base tables, Classes and Clubs, and a shared table, Students.

Classes	Clubs	Students
Fields: Class, a dimension with values of Nesting Basics, Advanced Songs, Flying for Fledglings, and Alarm Calls 101 Length, a measure Student, a dimension used to relate to the Student table	Fields: Club, a dimension with values of Photography, Travel, Juggling, Art, and First Aid Dues, a measure Student, a dimension used to relate to the Student table	Fields: Bus Rider, a dimension with values of yes or no Student, a dimension with values of Finch, Cardinal, Sparrow, Robin, and Jay. Used to relate to the other two tables Age, a measure

Unrelated dimension-dimension pair

One flavor of tooltip message is for an unrelated dimension-dimension pair.

Possible tooltip messages:

The message for an unrelated icon for a dimension-dimension pair, either on a shelf or in the Data pane (or in the warning dialog), is:

Unrelated dimensions can show combinations of values in the viz that don't exist in the data. Unrelated to: (list of fields).

In the Data pane, fields can also be de-emphasized with light gray text if they don't related to any fields in the viz. In this instance, the tooltip for an unrelated dimension-dimension pair is:

Not related to any dimensions in the viz. If used, this field can show combinations of values in the viz that don't exist in the data.

Unrelated dimensions can be cross joined or outer joined, which can result in combinations of dimension values across the headers that do not reflect actual combinations of data in the underlying tables.

• Unrelated dimensions, without the presence of a stitching dimension, are cross joined.
• Unrelated dimensions, in the presence of a stitching dimension, are each independently inner joined with the stitching dimension then those intermediate results are outer joined together.

Unrelated: Cross join	Stitched: Outer join of intermediate inner joins
A viz showing a cross join of Class and Club with rows for every combination of Advanced Songs/Alarm Calls 101/Flying for Fledglings/Nesting Basics with Art/First Aid/Juggling/Photography.	A viz showing the results of an outer join of the Student-Class inner join and the Student-Club inner join. Not all combinations of classes and clubs are represented, and there are rows for students and clubs without a class.

Unrelated dimension-measure pair

Another flavor of tooltip message is for an unrelated dimension-measure pair.

Possible tooltip messages:

The message for an unrelated icon for a dimension-measure pair, either on a shelf or in the Data pane (or in the warning dialog), is: 

Measure values repeat for unrelated dimensions. Unrelated to: (list of fields).

In the Data pane, fields can also be de-emphasized with light gray text if they don't relate to any fields in the viz.

• The tooltip for a dimension in the Data pane that is unrelated to all measures in use is:

  Not related to any measures in the viz. If used, measure values will repeat for this field.

• The tooltip for a measure in the Data pane that is unrelated to at all dimensions in use is:

  Not related to any dimensions in the viz. If used, this field will show repeated values.

When a measure isn't related to a dimension, it can't be broken down by that dimension's values (that is, it can't be individually aggregated at the level of those dimension values). Instead, the measure will be aggregated at a different level than the dimension headers in the view.

The result in a viz is a repeated value for the measure across the unrelated dimension's values. This behavior is similar to when an LOD expression is used to set the level of aggregation for a measure at a different level of detail from the native granularity of the viz. An unrelated dimension is essentially EXCLUDED from the computation of the measure's aggregated value.

• An unrelated measure, without the presence of a stitching dimension, is table scoped to its overall value and repeated for the unrelated dimension's values.
• An unrelated measure, in the presence of a stitching dimension, is broken down by the stitching dimension's values but repeated for the unrelated dimension's values.

Unrelated: table scoped and repeated	Stitched: both broken down and repeated
A viz showing the measure Dues (from the Clubs base table) with a single value repeated across every value of the unrelated dimension Class (from the Classes base table).	A viz showing the value for Dues broken down by each Student (Cardinal's dues are 100, Finch's dues are 60), but those values still repeat each time a student is repeated across multiple classes (Finch's dues are repeated for both of Finch's classes).

Filters

Relatedness is also evaluated for fields on the filter shelf compared to fields otherwise active in the viz.

Possible tooltip messages:

An icon and tooltip appears when a filter is unrelated to at least one field in the viz. Both the filter field and field in the viz have a tooltip.

• The tooltip for the pill on the filter shelf is:

  This filter ignores unrelated fields: <fields>

• The tooltip for the pill actively in the viz is:

  This field is ignored by unrelated filters: <fields>

The behavior of filters also depends on their relatedness to other fields in the viz. A filter doesn't impact the values of fields it isn't related to. Unless the filter is set to no values (excluding everything or including nothing), the viz will remain unchanged for any fields that aren't related to the filter. However, deselecting every option in the filter will return a blank viz.

Two screenshots of viz with an unrelated filter, showing that deselecting options in the interactive filter control doesn't impact the viz

Related fields are filtered as expected. In a more complex viz with a combination of related and unrelated fields (such as in a stitching context), the filter will only impact values that are related to the filter field.