Understanding Data Refresh in Power BI

What Is Data Refresh?

Data refresh is the process of updating the data used by a Power BI semantic model so that reports can reflect changes in the underlying source.

For example, suppose a sales database receives new transactions every day. If your Power BI report uses imported data, refreshing the semantic model can bring those new transactions into the report.

Without an appropriate refresh process, users may continue seeing older information.

How Refresh Works

A typical refresh workflow follows these steps:

1. Data is updated in the source system.
2. Power BI connects to the source.
3. Power BI retrieves or queries the relevant data.
4. The semantic model is updated, depending on the storage mode and refresh operation.
5. Reports display the latest available results.

The exact behavior depends on whether the model uses Import, DirectQuery, or a composite model.

Import vs. DirectQuery Refresh

Import mode

In Import mode, Power BI stores a copy of the data in its semantic model. A refresh retrieves updated source data and updates that stored copy.

For example, a daily refresh can import the latest transactions from a sales database.

DirectQuery mode

In DirectQuery mode, Power BI queries the underlying data source when visuals require data. Results can therefore reflect recent source changes without importing the entire dataset.

However, performance depends on the source system, query design, caching, and other configuration. DirectQuery does not guarantee that every visual always displays completely current data.

Composite models

Composite models combine supported storage modes. Different tables may have different refresh and query behaviors, so the model must be configured and tested carefully.

Refreshing Data Manually

You can refresh data in different environments.

In Power BI Desktop:

1. Open the .pbix file.
2. Select Home → Refresh.
3. Wait for the refresh to complete.
4. Verify that the updated data appears in the report.
5. Save and publish the report if the updated model needs to be deployed to the Service.

In the Power BI Service, users with the required permissions can initiate a semantic model refresh from the relevant workspace or semantic model settings.

Refreshing the Desktop file does not automatically update the published semantic model. You must publish the updated content or refresh the online semantic model as appropriate.