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Category: Warehousing

An Overview of Slowly Changing Dimensions

Published 2024-07-17 by Kevin Feasel

Reza Rad talks slowly changing dimensions:

If you want to use Power BI, Microsoft Fabric, or any other data analytics tools, one of the key concepts to understand when working with a data warehouse system is the SCD (Slowly Changing Dimension). I will do this in a series of at least two articles. The first one (this one) will be on the concept of what SCD is, its meaning, and its different types. Then, the next one will discuss how to implement SCD types (such as Type 2) using Microsoft Fabric and Power BI.

Reza focuses on SCD types 0-4 but does briefly touch on types 5-7 (of which, I’d never heard of SCD type 7).

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Microsoft Fabric Warehouse Access Control

Published 2024-07-02 by Kevin Feasel

Koen Verbeeck talks permissions:

We are starting a new analytics project in Microsoft Fabric, and our data will land in a warehouse. This is the first time we’re using Fabric, and we are wondering about the different options for sharing access to a warehouse we developed in a workspace.

Click through for more information on providing and limiting access to data in a Microsoft Fabric warehouse.

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Microsoft Fabric: Lakehouse or Warehouse?

Published 2024-06-12 by Kevin Feasel

Koen Verbeeck helps us choose:

This doesn’t mean no code has to be written. On the contrary, in this article we’re going to focus on two services of Fabric: the lakehouse and the warehouse. The first one is part of the Data Engineering experience in Fabric, while the latter is part of the Data Warehousing experience. Both require code to be written to create any sort of artefact. In the warehouse we can use T-SQL to create tables, load data into them and do any kind of transformation. In the lakehouse, we use notebooks to work with data, typically in languages such as PySpark or Spark SQL.

Read on for the comparison. I tend to go more for the lakehouse experience rather than warehouse, but Koen provides a lot of the info you’d need in order to make the right decision for yourself.

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Choosing between Data Warehouses, Lakes, and Lakehouses

Published 2024-06-11 by Kevin Feasel

Den Smyrnov talks architecture:

Historically, the two most popular approaches to storing and managing data are Data Warehouse and Data Lake. The choice between them usually depends on business objectives and needs. While Data Lakes are ideal for preserving large volumes of diverse data, warehouses are more favorable for business intelligence and reporting. Sometimes, organizations try to have the best of both worlds and mix Data Lake & Data Warehouse architectures. This, however, can be a time and cost-consuming process.

Against this backdrop, a new hybrid approach—Data Lakehouse—has emerged. It combines features of a Data Lake and a Data Warehouse, allowing companies to store and analyze data in the same repository and eliminating the Data Warehouse vs. Data Lake dilemma. Data Lakehouse mixes the scalability and flexibility of a Data Lake with the ability to extract insights from data easily. Ever so compelling, this approach still has certain limitations. It should not be treated as a “one-size-fits-all” solution.

Read on for an explanation of each of these three styles, including their pros and cons.

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Time Travel in the Microsoft Fabric Warehouse

Published 2024-05-24 by Kevin Feasel

Reza Rad hops in the Delorean:

Data changes throughout time, especially in the world of BI and data warehousing systems; the data gets updated through ETL processes frequently. This means that the data you see in the warehouse today might differ from yesterday and the day before, and so on. Some parts of this data can be retrieved on a timely basis. You can, for example, query the sales amount from the sales table where the date has been the 2nd of April. That would give you the sales amount for the 2nd of April, even if you are querying it on the 23rd of May.

However, what if some of the sales transactions on the 2nd of April got updated? The sales amount you see would likely be the updated amount, but not the original amount. It is sometimes useful to be able to see what was that original amount, or in other words, travel in time and see what that value was.

Click through for a combination video and article. The syntax isn’t quite the same as with temporal tables in SQL Server, though it’s close enough to follow along if that’s your relevant experience.

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Modern Data Warehousing with Data Lake Storage and Azure Data Factory

Published 2024-05-21 by Kevin Feasel

Josephine Bush continues a series on modern data warehousing:

In today’s data-driven world, having the right tools to manage and process large datasets is crucial. That’s where Azure Data Lake Storage (ADLS) and Azure Data Factory (ADF) come in handy, making it easier than ever to store and transform your data. In this post, I’ll show you how to set up ADLS to store your Parquet files and configure ADF to manage your data flows efficiently.

Read on for an overview of both technologies.

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Getting Row Counts of All Tables in a Microsoft Fabric Warehouse

Published 2024-05-03 by Kevin Feasel

Koen Verbeeck busts out the tally counter:

It says the data is 352MB in size, but after loading the data I was curious about how many rows were actually in that sample data set. Unfortunately, it’s not as straight forward as with a “normal” SQL Server database to get the row counts. First of all, when you connect with SSMS to the database there’s sadly no option to get the row counts report:

The post is a little depressing, really. But still worth the read.

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Implementing a Star Schema for a Power BI Semantic Model

Published 2024-04-22 by Kevin Feasel

Nikola Ilic reminds us to keep Ralph Kimball’s Data Warehouse Toolkit book at hand:

But, what is a star schema in the first place? I have good and bad news for you:)…The bad news is: I’m not covering it in this article, because this one focuses on explaining how to implement a star schema in Power BI (assuming that you already know what star schema is). The good news is: I’ve already written about it, so go and read this article first, if you’re not sure what star schema represents in the world of data modeling…

Now, let’s get our hands dirty and build a star schema!

Read on for the demo.

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Mirroring Snowflake to Microsoft Fabric

Published 2024-04-16 by Kevin Feasel

Reza Rad hogs the photocopier:

Microsoft Fabric offers an end-to-end SaaS analytics solution; however, the world is using all kinds of data sources in its implementation. Mirroring is a new functionality in Fabric that allows customers to keep their data wherever they are, but then they can use Fabric analytics solutions with the same speed and performance as if their data were in Fabric. Best of all, this won’t cost extra. If you wonder what it is and how it works, read this article.

Click through for the video and article.

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Mirroring Azure SQL DB into Microsoft Fabric

Published 2024-04-12 by Kevin Feasel

Dennes Torres holds up a mirror:

You need to read data from production to build a single source of truth. If you create pipelines reading directly from production, you will create additional load over the production environment. The mirror allows you to do much of the production reporting from the mirror, leaving the production environment to serve other users. Keep in mind, production report, but not analytics report.

Mirroring a production database to Fabric is one method to ensure the load over production will be as low as possible and the data will be transferred fabric to complete the transformations from this point.

Only this? What about avoiding pipeline creation? Not really, you still need to create pipelines, as I will explain ahead.

Click through for the demo and explanation. This is an important thing for people to note: mirroring doesn’t eliminate ELT. You still have the data lake process to work through, as your transactional system does not and should not look like your reporting system.

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