The Difference Between Power BI Connection Types

Power BI supports several different modes to connect to data, Direct Query, Import, Live Connections, and a hybrid model where you can use direct query and import mode within the same semantic model. We’ll explain the differences between each data connection type to help you determine the best one for your reports and dashboards.

The Importance of Connection Methods in Power BI

Power BI reports are designed to be developed once then connected to data sources that automatically update. This creates a couple of big benefits. It eliminates the need for people to create reports on a recurring basis, and it ensures that the person viewing the report always has the most up to date data.

For a report to automatically update, it has to be connected to a data source. The most common sources are Excel files saved one OneDrive or SharePoint, files on a network drive, or a database that’s hosted on premises or in the cloud.

The source of the data and the frequency at which it is updated will largely determine the type of connection method used.

Power BI supports several methods, Import Mode, Direct Query Mode, Live Connections and Composite Models. Before comparing the differences between them, it’s important to be aware that reports can effectively be built using any of these methods.

Power BI Import Mode

Import mode is the most common method of bringing data into Power BI. When in use, Power BI connects to various sources of data that could be the internet, a data warehouse, Excel files, or any of the 200+ connectors that Power BI supports. Data is then imported, compressed and stored in a Power BI file.

When report viewers interact with a report to change slicers or filters, Power BI will query the data stored in the Power BI file, also known as a semantic model.

Diagram of Power BI Direct Query mode architecture
Power BI Import Mode brings data from its source into Power BI before it’s retrieved by an end user.

With import mode, reports are published to PowerBI.com and set on a schedule to refresh data. When the schedule starts Power BI reaches out to the data sources, brings in new data and updates the report accordingly.

Using import mode offloads a majority of the data processing to the scheduled refresh time and locates the data in PowerBI.com.

Because of these reasons, this mode typically takes the longest to refresh, but provides users with the fastest report when they’re interacting with it. The biggest trade-off is that data will only be as up to date as the last refresh.

Data sources based on files, such as .xlsx, .csv and data sources like OneDrive and SharePoint only support import mode.

Power BI Direct Query Mode

Rather than importing data, Direct Query leaves the data in the source systems. When report viewers interact with a report, Power BI translates their request into a query and sends it to a database. This method can be slow when working with large datasets or if the source database is slow.

The benefit of Direct Query is that your data will always be up to date, and there is no requirement to setup a refresh schedule.

Power BI Direct Query Mode acts as a passthrough where report viewer queries are sent directly to the data source.

Direct Query is used with databases, data warehouses, and other sources of live data and does not support the ability to connect to files.

When a database is in the cloud, such as Azure, Snowflake, or many instances of Databricks Power BI can easily connect to them. When a SQL server exists on-premises, a Power BI gateway is required to bridge the connection from PowerBI.com to your organizations servers.

Power BI Live Connections

Live connections allow Power BI to connect directly to an Analysis Services database or to another Power BI Semantic Model. Refreshes are fairly quick, because you are building a report based on a semantic model that already exists.

The benefit of a Live Connection is that it allows developers to leverage semantic models that have already been created for another project. They allow you to build a data model once, and re-use it many times for different audiences, reports or dashboards.

The drawback of a live connection and sharing a semantic model between reports is that it can be difficult to go back and modify it later on. All of the subsequent reports that are connected to the original semantic model are dependent on it not substantially changing. If changes occur,

Power BI Composite Models

Composite models involve a blend of different data sources. This type of data model only exists when working with multiple data sources. You can setup some connections with Direct Query and other connections to Import. This method gives you some of the benefits of using each model.

A common use case is importing Excel or CSV files while connecting to a SQL database to pull in data. The combination of connection methods lets you work with flat files and gives users the ability to see up to date information coming from a database.

You can learn more about semantic models and connections from Microsoft here: Semantic model modes in the Power BI service – Power BI

Summary Table of Power BI Connection Types

The following table highlights the practical differences between using Direct Query, Import, and Live Connection methods when connecting to data in Power BI.

FeatureDirect QueryImportLive Connections
Data is loadedWhen a visual is created or interacted withWhen the dataset is refreshedWhen a visual is created or interacted with
PerformanceSlower than Import with large datasets or slow connections.Faster than Direct Query after scheduled data refreshes.Can be slower than Direct Query, especially for large datasets
FlexibilityCan be used with any data source that supports DirectQueryCan be used with any data sourceCan only be used with data sources that support live connections
CostCan be more expensive than import depending on data source and query frequency.Typically, less expensive than direct query due to fewer data transfers.Can be the same as DirectQuery, depending on the data source
RecommendationsUse for data sources that are frequently updated and that require the latest data.Use for data sources that are not frequently updated and that do not require the latest data.Use for data sources that are hosted in Power BI and that are frequently updated.

Choosing the Best Connection Method

Before you are being your report, you should determine which type of data connection to use. These are some of the most important things to keep in mind while building a report.

  • How Fresh Does the Data Need to Be? – Some users will want data that is up to date by the minute, this might be a manufacturing floor tracking variances or an accounting group interested in financials throughout the month end close process to see where net income lands. Other reports can be refreshed daily or semi-weekly for things like historic payroll trends.
  • Dashboard Performance – Report users love the flexibility of exploring data in Power BI. They do not love waiting for visuals to refresh after changing a slicer or filter. The connection mode has a large impact on user experience especially when large datasets are involved.
  • Data Source System – Not all source data supports Direct Query. Other times it would not make sense. If sales data is coming in from Oracle or SAP you may want the most up to date information. If sales are being consolidated from Excel Spreadsheets saved on OneDrive there would be no point to update them in real time.
  • Cost – Some cloud hosted data storage solutions charge businesses based on how much data flows in and out of a database. Direct Queries will cause more data to be pulled more often than scheduling a single import once a day of a dataset reducing user costs.
  • Data Availability – If you work for a company that has centrally curated a data warehouse or is very mature in their deployment of Power BI there may be data sources available to you that you can connect to and mitigate the need to build your own data model. Using something that

You should also explore if there are data sources already available within your company. If a business has central control over datasets, they may have already created a data warehouse, or Power BI data source that you can connect to.

Not all connection types will be ideal for each project. You can mix and match them to suit the needs of your project with the connection type. It’s very common to have a mix of different types across different reports.

Adam from Guy in a Cube also provides a great overview of the different connection types to help guide you through choosing the best one for your project.

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