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Category: Power BI

Calling Power BI REST API From Microsoft Flow

Published 2018-10-22 by Kevin Feasel

Chris Webb has started a series on calling Power BI’s REST API from Microsoft Flow.  In Part 1, he creates a custom connector:

Playing around with Microsoft Flow recently, I was reminded of the following blog post from a few months ago by Konstantinos Ioannou about using Flow to call the Power BI REST API to refresh a dataset:

https://medium.com/@Konstantinos_Ioannou/refresh-powerbi-dataset-with-microsoft-flow-73836c727c33

I was impressed by this post when I read it, but don’t think I understood quite how many exciting possibilities this technique opens up for Power BI users until I started to use it myself. The Power BI dev team are making a big investment in the API yet most Power BI users, myself included, are not developers and can’t easily write code (or PowerShell scripts) to call the API. With Flow, however, you can use the API without writing any code at all and solve a whole series of  common problems easily. In this series of blog posts I’m going to show a few examples of this.

In Part 2, Chris shows us how to automate data refreshes when source data changes:

For a while now I’ve had an idea stuck in my head: wouldn’t it be cool to build a Power BI solution where a user could enter data into an Excel workbook and then, as soon as they had done so, they could see their new data in a Power BI report? It would be really useful for planning/budgeting applications and what-if analysis. I had hoped that a DirectQuery model using the CData Excel custom connector (mentioned here) might work but the performance wasn’t good enough; using Flow with the Power BI REST API (see Part 1 of this series for details on how to get this set up) gets me closer to my goal, even if there’s still one major problem with the approach. Here’s how…

Read on for the approach as well as the major problem.

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Using R To Hit Azure ML From Power BI

Published 2018-10-16 by Kevin Feasel

Leila Etaati shows how you can use R to hit an Azure ML endpoint to populate a data set in Power BI:

You need to create a model in Azure ML Studio and create a web service for it.

The traditional example in Predict a passenger on Titanic ship is going to survived or not?

we have a dataset about passengers like their age, gender, and passenger class, then we are going to predict whether they are going to survive or not

Open Azure ML Studio and follow the steps to create a model for predicting this. Navigate to Azure ML Studio.

Then download the dataset for titanic from here

Click through for the step-by-step instructions.

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Power BI Data Profiling

Published 2018-10-16 by Kevin Feasel

Matt Allington takes a look at a new feature in Power BI:

The data profiling tools look at the first 1,000 rows in the preview data loaded an shows you the big picture of what the data “looks” like.

Currently the profiling tool only works on the top 1000 rows of data.  It also takes some time to prepare the profile of the columns (as could be expected), however the benefits of getting this stuff right before moving on far outweigh the slower load times (IMO).  I would love to see an option to profile the entire set of data for one or more columns.  I am sure this will come.

Teo Lachev shares some thoughts on what it would take to make this a killer feature:

That’s all data profiling you get for now. Here is what it will take to make Power BI data profiling a killer feature:

  1. Allow data profiling over all the values (understandably there will be performance impact).

  2. Add more aggregates, such as Min/Max/Std/Median.

  3. The ability to dynamically filter the preview data for the selected bar in the profile.

As it is, there’s enough here to see the potential of where it could go.

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Embedding Images In Power BI

Published 2018-10-11 by Kevin Feasel

Zach Conroe shows how you can embed an image in Power BI:

The good news is that there are workarounds to this challenge. We are going to reconstruct the above use case and demonstrate how to pull in images from a local database, and then use custom columns in Power Query to reformat the source data in a way we can render graphically.

Note: This same custom column technique can also be used to display images imported using a local folder as a data source. If you have Power BI Desktop installed, you can work through along with this post by downloading the .pbix file with this link.

In our sample database we have a couple of tables containing images stored in a binary format, as well as a few columns of metadata for the images. The images being used here are a JPEG file type, but this technique can also be used for PNG files. We imported the data into Power BI and loaded two tables of images: Examples 1 and 2. For the first example we used three small images in the table, as shown below.

There’s a 32K size limit that Zach mentions, which can be a bit painful to work within.

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Getting A Specific Rank In DAX

Published 2018-10-09 by Kevin Feasel

Marco Russo shows us how to get the Nth element in a list using DAX:

The complexity of the calculation is in the Nth-Product Name Single and Nth-Product Sales Amount Single measures. These two measures are identical. The only difference is the RETURN statement in the last line, which chooses the return value between the NthProduct and NthAmount variables.

Unfortunately, DAX does not offer a universal way to share the code generating tables between different measures. Analysis Services Tabular provides access to DETAILROWS as a workaround, but this feature cannot be defined in a Power BI or Power Pivot data model as of now.

Indeed, the code of the two measures is nearly identical.

Read on for code and explanation.

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Creating Minesweeper In Power BI

Published 2018-10-08 by Kevin Feasel

Philip Seamark has fun with a classic Windows game reimplemented in Power BI:

The latest addition to my recent series of DAX based games is the classic Minesweeper game.  This is the game where you are presented with a 9 x 9 matrix of squares.  There are 10 hidden mines and you can either step on a square or place a flag where you think there might be a mine.  If you are lucky enough not to step on a square that contains a mine, you will get clues that help you identify where the mines are.

Click here if you would like to see the final publish to web version.

Click here if you would like to download the PBIX version to go through the code.

Still better than the Windows 10 version.

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Analyzing Day-Over-Day Changes With Power Query

Published 2018-10-03 by Kevin Feasel

Dany Hoter shows how to use Power Query to join one row to the next in a data set (given similar criteria) and do day-by-day comparisons:

I want to analyze the daily prices of certain commodities and be able to show the patterns of daily changes side by side. I want to calculate predictably the differences between each row and the row before. Each row represents data for a day, so the difference between rows is the daily change or in some cases, several days change.

I downloaded from Quandl 50 years of daily prices of gold and silver, and my goal is to calculate the daily changes in terms of dollars and percentage from day to day. Not all days are represented, so in case of a gap I calculate the number of days in the gap, and I divide the growth % by the number of days. I already imported and appended the data for both metals into a single table in Excel and we’ll start the process from this table.

Read on for the solution.  I’d just as soon LAG() the data in SQL Server, but if that’s not an option, this certainly works.

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Running Totals In Power BI With M

Published 2018-10-02 by Kevin Feasel

Imke Feldmann gives us a reason to use M to calculate running totals:

Today I want to share a scenario where a running total calculation in the query editor saved a model that run out of memory when done with DAX:

Problem

The model couldn’t be refreshed and returned out of memory error with a calculated column in the fact table of over 20 Mio rows (from a csv-file). A running total should be calculated for each “JourneyID”, of which there were over 1 Mio in the table itself. This rose memory consumption during refresh by over 300 % – until it finally errored out:

Click through for the solution.

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Power BI: Datasets, Reports, And Dashboards

Published 2018-10-02 by Kevin Feasel

Eugene Meidinger teams up with Bert Wagner to teach Power BI using a food metaphor:

A Power BI Dataset is a series of Power Query queries that have been shaped in a DAX model. Each dataset can combine different files, database tables and online services all into one tabular model.  In our cookie analogy, these are all different “ingredients”.

Unlike SSRS, a dataset in Power BI does not represent a single table or query of data. A dataset should be considered more like a “flavor” of data used to accomplish a specific type of reporting: financial, operational, HR, etc. So in our analogy, the dataset is the “raw dough”.

So in Power Query, you are going to have a set of queries which each combine a data source with a usually linear set of transformations.

The pie chart cookie is the first one I would have eaten, if only to eliminate it.

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