Overview

Let’s look at one of the features that make Tableau a great data exploration tool. So, put on your explorer’s cap, and let’s go on an adventure! It’s time to learn about the Tableau Describe Feature.

Read more: Tableau Describe Advanced Uses »

Imagine this situation. You read about a really cool trick online that you can try on your next Tableau dashboard. You see an attachment of a workbook, and you say, ‘Oh great, I can see the tip in practice.’ You open up the workbook; you have absolutely no idea what is going on. So many new calculated fields, so many connected dots, you don’t even know where to start. And also, you don’t even know what is going on in the background of this workbook. You must reverse-engineer every sheet separately. What do you do?

Tableau Describe Function

Oh well, hello Describe!

The “describe” function in Tableau is something that most people overlook. Still, it has become one of my favorites since I’ve discovered it, for sure. If you’ve heard of this characteristic, it’s most likely that you’ve used it to define a certain dimension, measure, set, or parameter. Right-clicking on a field and selecting “Describe…” provides information like the data type and table from which it comes, but there are various more methods to use the describe function in Tableau to give an additional boost to your learning and analysis.

This article will teach you:

– How to make the most of the ‘Describe’ feature

– How to use the method for reverse engineering on someone else’s (or your own) Tableau workbooks

– Method for seeing underlying formulas and parameter permitted values

All of this will significantly reduce the processing time of your queries, speed up your learning or remind you of prior ways, and improve the efficiency of your calculated field authoring.

Keep reading: Tableau Data Analyst Certification Questions »

Data Types in Tableau

Tableau excels in a variety of tasks, including data visualization. When you connect to a data source in Tableau, the first thing you’ll notice is how it separates your data into dimensions and measurements. This is very helpful because you can now see exactly what your data may be used for.

Dimensions are used to divide data into chunks/groups/buckets. These are the tools you use to slice and dice your data. Dimensions produce row and column headers when dragged into a view. Then there are measurements, which are items on which you can perform math (I like how Tableau is alliterative: measures = math). These are often continuous-based data fields that provide an axis rather than a column/row header when dragged into a view.

But what more does Tableau have to say about our dimensions and measurements? Let’s have a look:

In the Data pane, you’ll note that each field has a symbol next to it that indicates the type of data Tableau considers it to be.

Icon	Data type
	Text (string) values
	Date values
	Date & Time values
	Numerical values
	Boolean values (relational only)
	Geographic values (used with maps)
	Cluster Group

That’s really cool. Tableau may not get it right the first time, but you can always utilize the Right-click menu to make changes and modify the data type.

Describe Feature

You may also see the word “Describe” on the Right-click menu. What effect does this have? Let’s take a closer look:

Here’s what you’ll see if you select Describe from the menu… a great goldmine of information regarding the field (size or measure) that you’ve chosen:

So, in a nutshell, use ‘Describe’ to explore dimensions in new data sets without having to load them into a viz (keyboard shortcut CTRL+E).

Let’s go together through all these delectable facts.

Role

Tableau shows you how it will interact with this field when it is used in a view. In this case, the Region field from Superstore Sales indicates that it is a Discrete Dimension; therefore, when I drag that field out into the Rows or Columns shelf, it will display a row or column for each member of the dimension.

Type

This tells me that this field is a database column. Another possibility is that it is a calculated field. Calculated fields are produced within the spreadsheet rather than in your data source. Here’s an example of how it might appear in the dialog box:

Remote Column

This is the column name in the underlying data source. This is very helpful because it might be difficult to recall what the field was originally titled if you want to rename your fields in Tableau to make them more relevant (because databases sometimes have funny naming standards). Using the remote column information, you may ensure that you refer to the correct field name if you need to contact your database about something involving this field. 

Keep on reading: Tableau Desktop Specialist Certification Questions »

Remote Type

Once again, this refers to the underlying data source and describes how it views that specific field. A new data type may be assigned to a field in Tableau in the same way that a new name can be assigned to a field. As an example, consider the postal code. Many databases treat this sort of data as numeric, but with Tableau, you may prefer it to behave like text. Did you overlook the initial data type of a field? To figure out what it was, use Describe.

Contains NULL

Does this field in your underlying data include any nulls? If so, here is the place to find out.

Locale

Was your Workbook designed for usage in Europe? That is indicated by this flag in the Describe dialog. Setting the locale, as discussed here, instructs Tableau on how to show certain information based on local preferences. European dates, for example, are frequently represented as dd/mm/yy rather than the mm/dd/yy format generally used in the United States.

Sorting flags

Is this field sorted in the underlying data source? If so, in what capacity? When underlying data sources, such as SQL databases, are produced as views, the view or query can be sorted by one or more fields. This is how you’ll know if the field you’re describing is a part of one of these.

Column Width

If the field has a fixed width in the underlying data source, as is common with ODBC connections to SQL Server or Oracle, that number will be displayed here.

Status

When it comes to calculated fields, it is not uncommon for a utilized measure or dimension to be altered or eliminated. This would render the computed field invalid, as illustrated above. TIP: In the Data window, incorrect computed fields are shown with a red exclamation sign (!).

Also, did you see the line at the bottom of the pop-up window?

When you click Load, you’ll see precisely what’s in that field. For dimensions, it will list all dimension members as follows:

Whereas for measures, Tableau will list the range of values that can be found in that measure.

Is it possible to get any better than this? Tableau has more information about your data than you can ever predict. To search the caverns of information that Tableau has to give about your data, simply right-click on your field and select Describe.

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