Tableau

Tableau from a SQL Server guy – Part 2

As I mentioned in my previous post, I have been playing with Tableau Desktop in my spare time. I am just experimenting with it and there are no structured instructions that I am following. In this post, I intend to connect to Excel data source and do some analysis. I chose the sample excel provided by Tableau which is mostly located in “My Documents\My Tableau Repository\Datasources\Sample – Superstore Sales (Excel).xls”. Once connected, Tableau will try to create Dimensions and Measures for you. It seems like, all the numeric field are converted to measures and string fields are converted to dimensions. To test my theory, I added two columns in the source excel. One called Sales Category with string values and other Weight with numeric values. Sure enough Sales Category became a dimension and Weight became a measure.

Strings are converted to dimensions and numeric values are converted to measures

Strings are converted to dimensions and numeric values are converted to measures

You will also observe a small icon beside each field. The icon kind of represents the data type. For e.g. ‘Abc’ means it’s a character data, a # represents numeric field. There are certain special icons. For e.g. a little globe means the field has something to do with geography data, small square with clock is date/time field, that chart like thing is a bin(more on this later) and pin is Group (again more on that later). You can change data type by right clicking on the field  and selecting Change Data Type. You can move stuff from measures to dimensions and vice a versa (of course if it makes sense!). For e.g. Order Id in measures does not make much sense, you can drag it to dimension panel and it will become a dimension. My gut feeling is that measure is treated just like another dimension, something similar to what SQL Server 2012 Tabular does. Creating a hierarchy is simple enough. Right click on a field from dimension panel and select create hierarchy. Drag the fields under the hierarchy name.

Hierarchies

Hierarchies

Coming to the bins and groups part mentioned above. I was a bit puzzled and struggled to get my head around the concept. Once I got hang of it, its is one of my favourite features. Bins are like buckets of data or data groups. For e.g you have a persons age as measure, you can group it in bins of 0-10,10-20,20-30 and so on or as ‘Kids’,’Adults’ etc. This tutorial is a good starting point.

That’s it for this post. In the next post, I am going to try to answer some questions based on some interesting datasets I have found using Tableau. So stay tuned!!

Tableau from a SQL Server guy – Part 1

If you follow the happenings in the Business Intelligence world, I don’t think Tableau needs any introduction. Gartner puts them in Challengers quadrant of Magic Quadrant for Business Intelligence Platforms. I have personally heard a lot about Tableau from a number of people and so thought I must give it a try.  Fortunately, Tableau provides a 14-day trial version of their product Tableau Desktop. Being a completely novice, I thought it might be a good starting point. I intend to write a number of posts on my experience with Tableau. They are, for sure, not intended as training or learning material but a mere   brief on features I encounter, what I like and a comparison with any equivalent features in SQL Server stack.  With that in mind, here’s the first post.

Getting started..

Getting started with Tableau Desktop couldn’t be easier. Just download the product from the official website. Installation is very straightforward. I accepted the defaults and it was just a matter of clicking Next. There might be some custom installation options but I will not cover them here. Once the installation is complete, you are presented with  Tableau Desktop homepage like below.

Tableau Desktop Home Screen

Tableau Desktop Home Screen

There is a Getting started guides and some samples at the bottom but I haven’t tried any of them. I will in few days and will post about them. Open Workbook link on top right will let you open any previously saved workbooks. This concept of Workbook in the context of Tableau is quite appealing. It is somewhat like your personal analytic space where your analysis is stored and much more. I am sure there are ways of sharing workbooks with your colleagues. In the MS world, the closest thing I can think of which is like the Tableau Workbook  is the PowerPivot model. As a matter of fact you can also consider a simple Excel file with all the charts and data as a Workbook.

Moving on, if you click on Connect to data link you are presented with screen like below which lists the various data sources from which you can pull data in Tableau. I must say I was very impressed by the list of data sources here. Seemingly every major data source is supported along with ODBC.

Tableau Desktop Data Sources

Tableau Desktop Data Sources

For this quick demo, I selected Microsoft SQL Server Analysis service and connected to our good old AdventureWorksDW. On successful connection, you are presented with the following screen.

Connected To AdventureWorksDW

Connected To AdventureWorksDW

The dimensions and measures are listed on the left. One of the features is that if you hover over any chart type on Show Me panel, it will be tell you what you need to build that chart type. But I think the best feature is this.Remember when you are browsing SSAS cube in Excel and if you analyse a measure by unrelated dimension, there is no indication that the dimension is unrelated and analysis in incorrect. SSAS merely repeats the sum-total of that measure for dimension members. Tableau, on the other hand, indicates to the user that the dimension is unrelated. See the screen shot below.

UnrelatedDimensionWarning

Unrelated Dimension Warning

If you see carefully, there is an warning sign beside Reseller Sales Amount with clear message. This is because one of the dimension I have used is not related to this measure. What’s more, Tableau will highlight only those dimension on the left panel which are related to the selected measure. I think this is a very versatile feature and a one which is certainly needed in Excel. Too many time I have seen users getting confused due to this and too many time I had to explain them why Excel is behaving the way it is behaving.

Ok, so after dragging and dropping stuff here and there, I managed to get a simple dashboard like below.

Quick Dashboard

Quick Dashboard

Not bad for half an hour effort,eh?? In the coming days, I am planning to play around more with Tableau and will definitely post my observations here.