Alexandra Payette
By Alexandra Oct 16, 2023

Exploring Your Data Connection Options in Power BI

Power BI is a robust tool that empowers not only our Business Intelligence team, but also data analyst professionals at large by facilitating the creation of interactive dashboards and visually engaging reports to extract essential information from complex data. When it comes to crafting a Power BI report, we are presented with a range of options for connecting the necessary data to create our visual elements. Within the platform’s offerings, you have the choice of three primary methods to establish the vital link between your data and your reports: data import, DirectQuery, or live connection.

Deciding on the best method for connecting to your data depends on your specific requirements and the nature of your goals. In fact, each approach has its distinct set of benefits and constraints, which can impact the performance and efficacy of your reports.

Alexandra, our Business Intelligence Analyst, has examined these three data connection methods in Power BI and will explore how to use them judiciously based on various business intelligence needs.

Why choose data import in a Power BI report

When incorporating data into a Power BI report, our team typically duplicates the data at a certain time and directly imports it into the report. This data then resides within a PBIX file, which is essentially a Power BI report encompassing all the data, queries, and visualizations. From there, we can leverage these components to craft a variety of visuals.

This is the preferred and most commonly used option, as it ensures that all functionality remains stored and managed within Power BI.

Note that data import does not provide real-time updates. To access refreshed and updated data, you will need to perform a re-import.

Importing data into a Power BI report
How to import data into Power BI

Benefits of the import method:

  • Fast and responsive: reports can be generated quickly, even with large amounts of data.
  • Full access to Power BI data connectors: you can connect to a wide range of data sources, including SQL, Excel, Analysis Services, Power Platform, Azure, SharePoint, Google Sheets, and more.
  • There is no restriction on the number of rows within tables.
  • Ability to perform all advanced operations (DAX, Power Query, etc.).
    • DAX, short for Data Analysis Expression, serves as the Power BI programming language employed for crafting measures and data operations. For instance, it can be used to create formulas for calculating metrics like the total income based on our dataset.
    • Power Query is the language utilized to directly transform data within Power BI. During the data import process, Power Query enables us to execute data transformation tasks, including renaming columns, introducing new ones, and reshaping the data. This ensures that the data is in the desired format, ready for the construction of visualization reports at a later stage.

Constraints of the import method:

  • Dataset size is capped at 1 GB unless you have Premium capability.
  • Data refresh frequency is restricted (without Premium capacity, daily updates are limited to a maximum of 8 times).
  • Once you’ve selected the import method, you cannot switch to DirectQuery for the connection.

In summary, the import method is the recommended choice in most cases, unless you have distinct and specific requirements that necessitate other connection methods. Its exceptional performance, user-friendly nature, and versatility in data transformation have solidified its popularity.

For example, the import method is preferred for dealing with medium-sized datasets, performing advanced data manipulations, or creating reports that integrate data from multiple sources. This approach ensures faster operations and provides access to the full range of Power BI capabilities. However, it may not be the ideal solution for real-time data requirements, where alternatives like DirectQuery or active connections may be more fitting.

When to use the DirectQuery data connection method

An alternative approach for connecting your data in Power BI is to use the DirectQuery method. With this connection method, you establish a direct connection to the data at its source, rather than importing it into the report.

Unlike data import, where data is extracted and stored within the platform’s data model, DirectQuery maintains a live, real-time connection with the original data source, such as a SQL database, data warehouse, or cloud service. In this method, the database schema, including the table structure and column names, is stocked within Power BI while your data remains at its source.

DirectQuery data connection method
How to use the DirectQuery method in Power BI

Benefits of the DirectQuery method:

  • Fewer constraints when dealing with larger datasets.
  • Real-time display of the most current data in your reports and dashboards, eliminating the need for manual refreshes.
  • Smooth operation and execution of various tasks within the report, as the data is not stored in the report itself.
  • Reduced storage space requirements on the service for housing the report.

Constraints of the DirectQuery method:

  • Data source connector limitations: DirectQuery is incompatible with Excel, MySQL, MongoDB, Google Analytics, and several other connectors.
  • The overall performance of your DirectQuery reports depends heavily on the performance of the data source. Slow data sources can result in delayed data display within Power BI. In addition, complex, numerous or poorly optimized queries can lead to longer response times.
  • Restrictions on data transformations and the use of DAX, which can limit the ability to create complex calculations and custom metrics.
  • Limit of 1 million rows displayed per query.

The DirectQuery connection method is most suitable when dealing with large datasets that undergo frequent updates and require regular refreshing. It’s the method of choice when real-time data is essential, bypassing the import method’s refresh limitations.

The differences from the live connection method

The live connection method is very similar to the DirectQuery approach. However, in this case, the connection is established directly to Analysis Services or an existing Power BI dataset. There are three avenues for implementing a live connection: through Azure Analysis Services, Azure Analysis Services (On Premise), or a Power BI dataset.

The live connection method essentially involves linking to an established dataset or cube and crafting reports based on this pre-prepared and modeled data source. Everything is retained within the model, and your role primarily involves data presentation. This approach is commonly used for connecting to real-time data sources like live databases or web services.

A live connection allows to connect to data in real time, similar to the DirectQuery method, but without the data being downloaded to the Power BI report, as queries are made at the source.

The live connection in Power BI
How to use the live connection with Power BI
How to use the live connection with Analysis Services

Benefits of the live connection:

  • Data is constantly updated in real time, so there’s no need to refresh it manually.
  • Utilization of DAX.
  • The live connection eliminates the need to store data in local data models, simplifying data management.

Constraints of the live connection:

  • No data model modifications available (Relations, Power Query)
  • Live connection data modeling can be more complex, as you must adapt to the structure of the underlying data source, potentially making reporting more challenging.
  • No access to the data view of the external source.
  • Restricted ability to connect to additional data sources in the report.
  • Limitation of connection to other data sources in the report. Unfortunately, it is only possible to import one data source at a time into a report.

The live connection method can be very useful when users want to connect to a dataset that has already been modeled, prepared and available for visual reporting. It also offers an excellent solution for those seeking real-time data connectivity. It’s a robust choice for organizations requiring immediate data access without local storage, but it does come with trade-offs regarding performance, modeling complexity, and security management.

Summary of the three data connection methods

In short, there are multiple ways to connect data in Power BI, each tailored to specific visual reporting requirements. These three methods each come with their own set of pros and cons, making a comprehensive understanding crucial for making well-informed decisions.

  • If you want to benefit from the full power of Power BI and optimum performance, the import method is your best choice.
  • If you need to process large volumes of data and ensure real-time updates, the DirectQuery method is the recommended solution.
  • If your goal is to generate visual reports without the need for data modeling and preparation, the active connection method is a suitable choice to fulfill your requirements.

The selection of a data connection method in Power BI depends on your specific priorities, the characteristics of your data, and your business intelligence requirements. The key is to understand the implications of each approach to get the most out of this powerful tool. If you have any specific inquiries about using Power BI to cater to your specific needs, our team of business intelligence professionals is available to assist you. Get in touch when you’re ready!

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