The Story of my Book, “Expert Data Modeling with Power BI”

Expert Data Modeling with Power BI
Expert Data Modeling with Power BI

In 2020, the world celebrated the new year with many uncertainties. Well, life is full of uncertainties, but, this one was very different. The world was facing a new pandemic that never experienced before. The first COVID19 case in New Zealand was confirmed in February 2020. In March 2020 the entire country went to lockdown for the first time. The world was experiencing a massive threat changing everyone’s lives. I was no different. Every day was starting with bad news. A relative passed away; a friend got the virus; the customers put the projects on hold etc. Nothing was looking normal anymore. You can’t even go to get a proper haircut, because everyone is in lockdown. This is me trying to smile after getting a homemade haircut. I bet many of you have done the same thing.

Soheil's Homemade Haircut
Soheil’s Homemade Haircut

One day, I checked my email and saw a message from Packt Publishing. They wanted to see if I am interested in writing a book about Power BI. That was a piece of good news after a long time. I always wanted to write a book about Power BI. Indeed, I attempted for the first time in 2016, but I couldn’t manage to get my ducks in a row to grasp the publishers’ attention.

I was not unfamiliar with writing books; indeed, I wrote my first book back in 2006 about Multimedia Applications in Persian. One of my passions in life is listening to music. And CDs were the most accessible music source with high-quality sound. I recall I saved money for some months, and I bought a Discman to listen to the music on the go. But CDs are rather bulky, and you could not have many of them in your pocket. So the next project was to save even more money to buy an MP3 player. But, converting Audio CDs to MP3 without compromising a lot on the sound quality was a real challenge for many people. And, that was my motive to write my first book in Persian to share my little knowledge with everyone. 

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Quick Tips: Connecting to Excel Files Stored in SharePoint Online from Power BI Desktop

Connecting to Excel Files Stored in SharePoint Online from Power BI Desktop

Microsoft Excel is one of the most common data sources for Power BI. We can store Excel files in various storage types. The way we get data from Excel varies depending on the storage type. In this post, I quickly show two methods to connect to an Excel file stored in SharePoint Online.

Method 1: Getting the Excel File Path from the Excel Desktop App

This method requires you to have the Excel application installed on your machine. In this method, we open the Excel files stored in SharePoint Online in the Excel Desktop App in our machine and get the file path from there.

In SharePoint Online go to the desired document library then follow these steps to make it work:

  1. Select the Excel file
  2. Click the Open button
  3. Click Open in app
Opening Excel file from SharePoint Online in Excel Desktop App
Opening Excel file from SharePoint Online in Excel Desktop App

This opens the Excel file in the Excel Desktop application. In the Excel follow these steps:

  1. Click the File menu
  2. Click Info
  3. Click the Copy path button
Copying Excel Path from Excel Desktop App
Copying Excel Path from Excel Desktop App

So far we got the Excel file path. The step is to get data from the copied path in Power BI Desktop.

Open Power BI Desktop and follow these steps:

  1. Click Get data
  2. Click Web
Getting data from Excel stored in SharePoint Online in Power BI Desktop
Getting data from Excel stored in SharePoint Online in Power BI Desktop
  1. Paste the path we copied from Excel in the URL text box
  2. Delete the ?web=1 from the end of the copied path
  3. Click OK
Modifying the path copied from Excel to get the data in Power BI Desktop
Modifying the path copied from Excel to get the data in Power BI Desktop
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Quick Tips: Renaming All Tables’ Columns in One Go in Power Query

Renaming All Tables' Columns in One Go in Power Query

I previously wrote a blog post explaining how to rename all columns in a table in one go with Power Query. One of my visitors raised a question in the comments about the possibility to rename all columns from all tables in one go. Interestingly enough, one of my customers had a similar requirement. So I thought it is good to write a Quick Tip explaining how to meet the requirement.

The Problem

You are connecting to the data sources from Power BI Desktop (or Excel or Data Flows). The columns of the source tables are not user friendly, so you require to rename all columns. You already know how to rename all columns of a table in one go but you’d like to apply the renaming columns patterns to all tables.

The Solution

The solution is quite simple. We require to connect to the source, but we do not navigate to any tables straight away. In my case, my source table is an on-premises SQL Server. So I connect to the SQL Server instance using the Sql.Database(Server, DB) function in Power Query where the Server and the DB are query parameters. Read more about query parameters here. The results would like the following image:

The Results of Sql.Database() Function in Power Query
The results of running the Sql.Database(Server, DB) function

As you see in the above image, the results include Tables, Views and Functions. We are not interested in Functions therefore we just filter them out. The following image shows the results after applying the filter:

Filtering out SQL Server Functions After Connecting from Power Query
Filtering out SQL Server Functions

If we look closer to the Data column, we see that the column is indeed a Structured Column. The structured values of the Data column are Table values. If we click on a cell (not on the Table value of the cell), we can see the actual underlying data, as shown in the following image:

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A Power Query Custom Function to Rename all Columns at Once in a Table

A Power Query Custom Function to Rename all Columns at Once in a Table

I am involved with a Power BI development in the past few days. I got some data exported from various systems in different formats, including Excel, CSV and OData. The CSV files are data export dumps from an ERP system. Working with ERP systems can be very time consuming, especially when you don’t have access to the data model, and you get the data in raw format in CSV files. It is challenging, as in the ERP systems, the table names and column names are not user friendly at all, which makes sense. The ERP systems are being used in various environments for many different customers with different requirements. So if we can get our hands to the underlying data model, we see configuration tables keeping column names. Some of the columns are custom built to cover specific needs. The tables may have many columns that are not necessarily useful for analytical purposes. So it is quite critical to have a good understanding of the underlying entity model. Anyhow, I don’t want to go off-topic.

The Problem

So, here is my scenario. I received about 10 files, including 15 tables. Some tables are quite small, so I didn’t bother. But some of them are really wide like having between 150 to 208 columns. Nice!

Looking at the column names, they cannot be more difficult to read than they are, and I have multiple tables like that. So I have to rename those columns to something more readable, more on this side of the story later.

Background

I emailed back to my customer, asking for their help. Luckily they have a very nice data expert who also understands their ERP system as well as the underlying entity model. I emailed him all the current column names and asked if he can provide more user-friendly names. He replied me back with a mapping table in Excel. Here is an example to show the Column Names Mapping table:

Column Names Mapping

I was quite happy with the mapping table. Now, the next step is to rename all columns is based on the mapping table. Ouch! I have almost 800 columns to rename. That is literally a pain in the neck, and it doesn’t sound quite right to burn the project time to rename 800 columns.

But wait, what about writing automating the rename process? Like writing a custom function to rename all columns at once? I recall I read an excellent blog post about renaming multiple columns in Power Query that Gilbert Quevauvilliers wrote in 2018. I definitely recommend looking at his blog post. So I must do something similar to what Gilbert did; creating a custom function that gets the original columns names and brings back the new names. Then I use the custom function in each table to rename the columns. Easy!

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