How to Materialize DAX Calculations into a Power BI Model

“Materialize” is a database concept that refers to storing the result of a query, often in conjunction with a SQL view. The advantage here is that when using the result set you can query stored values as opposed to having to run calculations with typically a significant improvement in response time.

What is DAX calculation?

DAX (Data Analysis Expressions) calculations are formula-based expressions used in Power BI and other Microsoft tools to perform data transformations, calculations, and aggregations on tables and columns within a data model. These calculations enable users to create custom measures, calculated columns, and calculated tables to derive valuable insights and metrics from their data.

Materialize and Synchronize Power BI Model with a Data Warehouse

Recently a customer asked us to “materialize” DAX calculations in a Power BI model to their data warehouse. In this blog, I will cover a very simple approach to realizing this.

A key requirement here is to understand the nature of DAX calculations: these are -contrary to common belief- not associated with a table in Power BI but a “freestanding” semantic concept that can be associated with any table of the model (even a calculated one – more here later).
The results of a DAX calculation only exist in conjunction with a query or table, so we need to look at materializing that.

Typically, you have 2 options in Power BI: either create a calculated table or add a calculated column with the measure(s) that you want to materialize.

Option 1: Calculated Table

This approach will use a DAX measure like SELECTEDCOLUMNS() to create a measure table with columns from the source table that you want to use with the measure and the measure(s):

Option 2: Calculated Column

This approach uses a straightforward addition of a calculated column to the table where you want to materialize:

Simple Export

A simple approach to materialize either result set is to export the table data file and load that to where you need the materialized results.

Automated loading to a Data Warehouse

A more elegant and automated way is available via the Acterys Power BI Sync External Tool which can be downloaded from this link: https://landing.acterys.com/power-bi-sync and only takes a few seconds to install.

Once installed you can just configure the access details of your target server where you want to store the materialized tables and then just point to it and click on export:

Power BI Sync also allows you to automate this task and run the load process in a chosen time interval:

Write-back & Planning

With an Acterys subscription this table is then also immediately “write back” enabled and can be used with all the planning features that are included in the solution:

Key Takeaways

1. Materializing query results, especially in conjunction with a SQL view, can significantly enhance response times when working with data.

2. Understanding that DAX calculations are not tied to a specific table but are a semantic concept in Power BI is crucial. Materializing DAX calculations can improve their performance.

3. You have two primary options in Power BI for materializing DAX calculations: creating a calculated table or adding a calculated column to an existing table.

4. You can easily materialize your DAX calculation results by exporting the table data file and loading it where needed, offering a straightforward approach.

5. For a more automated and elegant solution, you can use the Acterys Power BI Sync External Tool, which allows you to configure access to your target server and automate the materialization process, making it efficient and convenient.

FAQs

1. What is materialization in the context of databases and Power BI?

Materialization refers to storing the result of a query or calculation so that it can be readily accessed without the need to recompute it. In Power BI, this can lead to significant improvements in response times.

2. Why should businesses materialize DAX calculations in Power BI?

Materializing DAX calculations can enhance performance by allowing you to query stored values instead of recalculating them every time, resulting in faster report generation.

3. Are DAX calculations tied to specific tables in Power BI?

No, DAX calculations are not inherently tied to a specific table in Power BI. They are a semantic concept that can be associated with any table in the model, even calculated tables.

4. What are the two primary options for materializing DAX calculations in Power BI?

The two main options are:

• Creating a calculated table that includes the desired DAX calculations.
• Adding a calculated column to an existing table where you want to materialize the results of DAX calculations.