Storing historical data in Power BI can be accomplished by implementing proper data modeling and utilizing the built-in capabilities of Power BI. Even if the data disappears or gets updated in the server end, you can still maintain historical records in Power BI using the following methods:
Data Refresh Options: By default, Power BI will attempt to refresh the data in your reports and datasets based on the data source settings. However, you can configure the data refresh options to keep the historical data even if it changes in the source. This can be done by going to the dataset settings in Power BI service and choosing "Keep data history" under the "Data Connectivity" tab. This ensures that Power BI keeps track of the changes made to the data over time.
Versioning with Query Parameters: You can implement versioning in your data model using query parameters. Create a query parameter that represents the version of the data you want to retrieve. This can be a date or any other identifier that represents a specific point in time. Then, in your queries, use this parameter to filter the data based on the selected version. This way, you can always go back and view historical data by changing the parameter value.
Snapshot Tables: Another method is to create snapshot tables in your data model. These tables capture the state of your data at specific points in time. You can set up a process to periodically copy the data from the source into these snapshot tables. This way, even if the original data changes or disappears, you'll still have historical data preserved in the snapshot tables.
Archiving Data: Depending on your data source, you may have the option to archive historical data before it disappears. Archiving data involves moving older records to a separate database or storage location while keeping your primary dataset focused on the most recent data. Power BI can then be connected to both datasets, allowing you to access historical and current data in separate reports.
Version Control: Consider using version control systems like Git to manage your Power BI files. This allows you to maintain historical versions of your reports and datasets, ensuring that you can always go back to previous states if needed.
