2 Replies Latest reply on Aug 28, 2012 12:53 PM by Paul Charbonneau

    Why do I get a field called Calculation_XXXX after I refresh my data extract?

    Paul Charbonneau

      I've had to refresh my data a few times due to some cleansing exercises that we've had to do, so I have to reload my data.


      In creating a series of dashboards, I added several custom calculation fields to my dimensions based on the data fields that came in.  Yet when I refresh my data extract, I end up getting a bunch of fields called Calculation_XXXXXXXXX.  Because there are almost a dozen, I have now intention of building them again, nor am I able to look into those fields to see what the original calculation is, so I can rename them appropriately.


      Where am I going wrong?



        • 1. Re: Why do I get a field called Calculation_XXXX after I refresh my data extract?
          Russell Christopher

          Hi Paul -


          Are you saving your workbook after refreshing or optimizing your extract




          • You create a new calculated field called "Full Name", which is [First Name] + " " + [Last Name]
          • You save the workbook ("I'm safe now", you think)
          • You choose Extract | Refresh or Extract | Optimize at some later point
          • You close the workbook WITHOUT saving


          This pattern of usage would cause a "Calculation_XXXX" field to show up in your workbook instead of "Full Name"


          Why, you ask? When you refresh or optimize an extract we (where possible) actually turn your calculated fields into physical fields inside the extract with [First Name] + " " + [Last Name] values saved and pre-calculated. We also "re-map" your old calculated field ("Full Name") to the new column in your extract.


          If you close Tableau at this point we'll actually prompt you to save. You might think "yeah, yeah, I saved already" and choose not to. If you don't here's what'll happen:


          • There's now's a new field in your extract (calcuation_xxxx) that the workbook has no idea what to do with. The "mapping" information didn't get saved, after all.
          • The original "Full Name" calculation doesn't show up either - it was (sort of) deleted and replaced with the new "mapped to the extract column" equivalent which was never saved.


          Kind of complicated. Moral of the story - always save after doing anything extract-related. Even if you don't think you've changed the workbook, you have.

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          • 2. Re: Why do I get a field called Calculation_XXXX after I refresh my data extract?
            Paul Charbonneau

            I've been doing a lot of data cleaning and still learning how this thing works.

            Seems I have to stay in the workbook I started and save everything in there.


            I have no idea why Tableau wouldn't save the actual equations when I save my new stuff as a saved datasource.

            I'm going to want to adjust those calcs at some point.  A lot of my custom calcs are range groupings for age, income, sales price, regions, etc.  Just annoying.


            I'll try to make sure I keep everything in the same place.  Or I might have to edit my back end data extraction to create the values for me, then I can modify the results in my sql scripts when loading in the data. (also not a great option)