• David Goldstone

How big is this data source?

Tableau makes it wonderfully easy to analyse and visualize large amounts of data.

This could be a live connection to a MySQL database, an extract from an SQL database, a Excel document, or any other data source from the bucket-load of choices that Tableau connects to.

Then, what happens if you want to analyse a multiple set of .csv files that are so huge that Excel creaks or doesn't even respond when you try and open it, in an attempt to play with the files?

Our little, but under-rated friend, "Append data from file" is here to help.

Here is a use-case to help explain this wonderful little nugget.

You have a client that has a Sales data-source sitting in a 100mb .csv. This isn't ideal, but it's all they have. Not only do they have one file, they have six of them. One for each month.

Excel won't even entertain the idea, nor will any other tool to merge them together. To make it more fun, they don't have this data sitting a lovely little database. 

So, what do we do? 

Connect to one of the .csv files and extract the data to .hyper (or .tde prior to 10.5) as you would normally.

Once extracted, save the file as you normally would.

Right Click the Data Source in the left-hand data pane, select Extract, Select Append Data from File. Select the next .csv, click Open.

Tableau will then start to import the data and will tag it on to the end of the first data-set that you have imported. Save the file.

Repeat this process until you have appended all your data sources. 

Note: You must ensure that all the data sources are in the same format and have the same column names in the same order. If not, then you will have to use Tableau Prep. This is a new tool from Tableau that allows you to "prep" your data. I will write about this another time.

But, that should complete the "Append Data from File" and allow you to now Analyse and Visualize your multiple over-sized .csv. 

Now you can have fun vizzing up your data!

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