Tableau’s ‘Describe’ feature helps you learn more about individual fields, worksheets, and calculated fields, but also helps save valuable processing time, reverse-engineer workbooks, and save you clicks when reusing previously coded syntax.
Hi. This is Ryan with Playfair Data TV. And in this video, I’m going to be sharing a technical feature called Describe, and also three ways this Describe feature is going to help you get the most out of your analyses in Tableau.
So first, to show you what the Describe feature is and the way that most people learn how to use this for the first time, I’ve got the Sample Superstore data set open over here in Tableau Desktop. And if I was wanting to learn more about an individual field, what I could do is right-click on it. So I’ll right-click on the Category field. And the last option, down at the bottom, is to describe that dimension.
And if I click on that, this little window will open that will give you some information about that specific dimension. So it’s showing us things like, what column does it come from in this database table? What’s the data type? What’s the locale? Is it case-sensitive? So there’s some information there about that dimension.
But my favorite way to use this feature is to click on the Load button in the bottom-left corner of this little interface here. And when you do that, you will see a preview of the first 20 dimension members within that dimension. The Category dimension happens to only have three. So we’re actually looking at all three of them there– Furniture, Office Supplies, and Technology.
Before I was introduced to this Describe feature, what I would have to do, if I wanted to learn what the dimension members were within a dimension, is drag that dimension onto the view– either to the Rows Shelf or Columns Shelf– just to see what the dimension members were. You can see that loaded up pretty quickly for me. It’s because the sample data is only 10,000 rows, so not a big deal.
But if I was dealing with a more enterprise-level database, with millions and millions of rows in it, it would be unnecessary for me to drag a dimension onto the view just to see what the dimension members were. That might make me have to sit here and wait for a few minutes for it to load up. With the Describe feature, it’s much faster to learn more about an individual field.
So that’s the way that most people know of the Describe feature and how to use it. But there are some other ways that Tableau will help you describe what’s happening in a view. To show you two more ways that the Tableau Describe feature can help you out, I’m going to jump over here to a dashboard I call the Super Sample Superstore dashboard, which I use to help teach strategy and different tactics. This is just one individual view within this workbook.
But let’s say this was a real-life scenario, and maybe a colleague passed me a dashboard to build on it. Or perhaps you’re over there at home, training on Tableau, and you want to download a dashboard from Tableau Public so that you can reverse-engineer it and figure out what’s happening. This would be a good example. You might land on a sheet like this. You see there’s no axes. So it might be a little bit tricky to tell what’s going on.
Well, in addition to being able to describe individual dimensions, you can also describe entire worksheets. To do that, you click Worksheet in the top navigation. And then the fourth option from the bottom is to describe this sheet. And this gives you all kinds of information.
It’s telling us what fields are being used, that the mark type is automatic, that stack marks is off, what’s on the Rows Shelf, what’s on the Columns Shelf. How are the data points being filtered? Are there any calculated fields on the view? If so, it’ll show you the underlying code that is creating that calculation. So there is all kinds of information on here to learn about this specific worksheet. So if you’re not used to looking at the location of the pills on the Columns and Rows Shelf, and how those are encoding the marks, this is an alternative way that will help you reverse-engineer somebody else’s Tableau workbook.
Then one more way the Describe feature can help you out– if you ever see a calculated field on the Data pane, so any of these fields that have a little equal sign before its data-type icon, what you can do is right-click on one of those fields and click Edit. And this will open up the calculated field.
So again, just pretending that we’re reverse-engineering this from Tableau Public, let’s say you see this Date Equalizer calculated field in the workbook. You want to figure out what’s happening behind the scenes to make that work. You can right-click on it. Click Edit. It will open up this calculated field dialog box, where you can see the logic that is creating this computation.
But how the Describe feature comes into play here is if I am nesting calculated fields– so if any of these orange fields within my calculated field are also calculated fields, I can click on those to see what the formula is. So I clicked on Date Filter CP. And when I did that, over here in this right window, it’s showing me the underlying formula for that other calculated field. So it’s a calculated field within a calculated field.
I do this all the time. I either need to figure out how the data is being aggregated, or sometimes I want to copy some of the logic that I had wrote previously and then paste it into a new calculated field. So I do this all the time.
But it has one drawback. I’m not able to copy and paste this calculation. So I’m left-clicking in this right window over here. But nothing’s being highlighted. So I’d have to manually type that out again. Not too big of a deal with four lines of code here. But I’m sure as you know, some of these calculated fields can get quite long. I don’t want to have to retype all that logic again.
Well, this is my third tip for you on how to use the Describe feature. Notice at the bottom, there is that button to describe this calculated field. And if I click on that it gives me some information about the calculation. But it also gives me this little window that I can now copy and paste the code from.
So this time, when I left-clicked and dragged to highlight the calculated field, it actually highlighted. And if I copy that– I’ll do Control-C to copy, close this window, and Control-V to paste. There is the calculation.
Obviously, this isn’t valid. I’m not done writing the formula. But this is a way to help me save some clicks. If I had not known about this Describe feature, what I would have to do if I wanted to replicate this logic is I’d have to take note of this calculated field name, click OK to close this window, go find the other calculated field, right-click on it, click Edit, copy the formula, close it, go back to the original.
So as you can see, there’s lots of steps that we save by using this Describe feature.
This has been Ryan with Playfair Data TV – thanks for watching!