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Category: Power BI

Converting Hexidecimal to Decimal with Power BI

Published 2020-07-31 by Kevin Feasel

Soheil Bakhshi has a great function for us:

A while ago I wrote a blogpost on how to use Unicode characters in Power BI. In that blogpost I used a recursive Power Query function to convert Hex values to Dec values. A few weeks back one of my site visitors kindly shared his non-recursive version of Power Query function which beautifully does the job. A big shout out to Rocco Lupoi for sharing his code. So, I decided to share it with everyone so more people can leverage his nice Power Query function. I have touched his code a bit though, but it was more cosmetic change, so all the credits of post goes to Rocco. 

Click through for the details.

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Creating Power BI Measures via Visual Studio Code

Published 2020-07-30 by Kevin Feasel

Phil Seamark goes one step further with TOM:

My last blog introduced the idea of using Microsoft Visual Studio Code to work with Power BI Models. For this article, I build on that idea by showing how you can use a TOM based script to automatically generate measures in your model Power BI (or Azure Analysis Services) model.

For simplicity, the example in this blog will do the following:

– Connect to an instance of Power BI Desktop
– Iterate through every Table in the model
– Iterate through every Column in the “current” table from the outer loop
– If the Column is numeric and not hidden, create a simple [Sum of <column>] measure

Read on for demonstration code and a walkthrough of the process.

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Loading Data from S3 into Power BI

Published 2020-07-30 by Kevin Feasel

Gilbert Quevauvilliers loves a challenge:

I really enjoy a good challenge, and with my customer they have all their data stored in AWS S3. Whilst there is no native connector, I thought there must be a way for me to get the data from AWS S3 into Power BI.

I did a bit of Googling and could not find any suitable solution. I also found and learnt that I could use AWS Athena to query the data living in S3. (I am definitely an expert of have a lot of knowledge in the AWS space. I am fortunate that I have other people who know AWS and were able to setup, configure and give me the details to connect to S3 via AWS Athena)

Below are the steps on how I got this working.

Why they don’t have a proper connector is a bit of a head-scratcher to me given the sheer amount of data stored in S3 and the sheer number of connectors in Power BI.

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Adding a Last Updated Time to Power BI Reports

Published 2020-07-30 by Kevin Feasel

Ed Hansenberry adds useful information to a Power BI report:

It is often useful to tell your users when the report refreshed so they have some idea of how current, or stale, the data is. Unfortunately, you cannot just add a TODAY() formula to your report as that will change each time they open the report. This method will give you the refresh time stamp and compensate for Daylight Savings Time.

This frustrates me a bit—the time when the report was generated is really easy to do in Reporting Services and is certainly a good practice to follow when building reports, and yet there’s a multi-step process involving writing M code to do something which ought to be trivial.

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Futureproofing a Power BI Solution

Published 2020-07-29 by Kevin Feasel

Paul Turley begins a series on doing Power BI the right way:

The purpose of this post is to provide some guidance to help you design Power BI solutions that can survive the journey through these stages with as little “throw-away” design as possible. There will always be prototyping and redesign in any project but if you follow proven design patterns and lessons learned from prior experience, you’ll have a much better chance of building a reporting solution that will endure.

Oh, I should mention this… the difference between item #1 (the simple prototype) and #2 (working proof-of-concept) is that you need to throw away the first one – and anything else that doesn’t lay a foundation that you can build on top of. This is a hard lesson but one that will pay off by helping our teams, sponsors and business stakeholders understand that we can proceed after laying down solid bricks (based on well-defined functional and technical requirements) to build the rest of the solution.

That italicized part was important enough for me to call it out. Far too often we develop proofs of concept which work well enough for a demo, and then the next question is “Great, when will it be in production?”

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Connecting Excel to Power BI as an External Tool

Published 2020-07-28 by Kevin Feasel

Erik Svensen adds to the External Tools parade:

When I build models – I use Excel pivot tables to test and validate my measures and typically I would use DAX Studio to find the localhost port to setup a connection to the currently open PBIX file.

So, I thought it be nice just to click a button in PowerBI Desktop to open a new Excel workbook with a connection to the current model. That would save me a couple of clicks.

If I could create an ODC file when clicking on the button in Power BI and then open the ODC file (Excel is the default application to open these) my idea would work.

And that’s exactly what Erik has done, using Powershell to do the work.

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Documenting a Power BI Model

Published 2020-07-28 by Kevin Feasel

Marc Lelijveld has taken advantage of external tools in Power BI:

Yes, really! I build and External Tool to document your Power BI Model. I know, documentation is not a very famous topic, but I believe a very important one! Lead time from data to insights is very short with Power BI, but often we forget to look back on what kind of monster we created. Especially if you want to share the dataset for reuse, I believe it is important to deliver some documentation as well. Maybe you even promote or certify this dataset in the future, which implicates that the model matches certain quality metrics and best practices.

Read the whole thing and check out Marc’s offering.

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Using Dynamic Datasets in Power BI

Published 2020-07-27 by Kevin Feasel

Jose Mendes implements the screening pattern in Power BI:

I recently came across the need to build a screening pattern based on the Kimball “Screening” concept. One of the desired outputs was a Power BI report that allowed a data steward to easily identify the failed screen, drill down to the detail and show the row(s) rejected by the data quality rule. To achieve this goal, I had to mimic in Power BI an SSRS functionality called dynamic dataset, which allowed me to, using a single matrix, show different source columns based on a selected screen. Feeling curious already? Then, let’s dive into the details.

A screen is designed to operate on a single input file or database table and contains the data quality condition to check. For example, there could be a Missing Customer Postcode screen which would test for any customers who are missing a postcode.

Read on for an implementation.

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Python and Power BI Desktop

Published 2020-07-24 by Kevin Feasel

David Eldersveld continues a series on Python as an external tool in Power BI. Part 2 is about defining a proper JSON formatted file:

To see a new tool in the Power BI Desktop ribbon, you need to define a JSON file and place it in a specific folder on your workstation. The featured external tools Tabular Editor, DAX Studio, and ALM Toolkit have installers that take care of this step. Since you do not have a dedicated installer to place this file in the required directory, you need to manually define your own.

As long as the “enhanced metadata format” for the data model is enabled, and the JSON in your file is accurate, you should see your new tool in your ribbon after you re-open Power BI Desktop.

Part 3 shows off virtual environments in Python as well as how to connect to the Tabular Object Model:

The Tabular Object Model (TOM) library for .NET opens Power BI’s data model to external tools. Two pieces are required to allow Python to interface with .NET:
1) Pythonnet package for .NET CLR (pip install pythonnet)
2) Python-SSAS module (ssas_api.py placed in the same folder as the main script you’d like to run)

The python-ssas (ssas_api.py) Python module that facilitates the TOM connection is all the work of Josh Dimarsky–originally for querying and processing Analysis Services. I simply repurposed it for use with Power BI Desktop or the XMLA endpoint in Power BI Premium and extended it with some relevant examples. Everything relies on Josh’s Python module, which has functions to connect to TOM, run DAX queries, etc.

This does look pretty handy.

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Marking a Table in DAX as a Date Table

Published 2020-07-24 by Kevin Feasel

Alberto Ferrari explains why you have to mark a date table as such in Power BI:

Even though this probably does not surprise you, in fact it should. The measure – as it is written – should not work. The reason why it works is because the relationship between Sales and Date is using the Sales[Order Date] column. Sales[Order Date] has a Date data type. If we use an integer to relate the two tables instead of using a Date column, the formula stops working. We now change the relationship using the integer column Sales[OrderDateKey] instead of the Sales[Order Date].

Read the whole thing.

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