How to store old data before refreshing to plot a chart

[PBI_newuser]

Hi, I want to store the old data so that I can know the open cases count for each day as screenshot below.
How can I do that?

[edhans]

Power BI is a read-only product. It cannot efficiently store archival data. You need your source system to maintain copies of data, either in a separate table, the same table but with dated records, or if your data is file based, save a different file for each time data is saved then combine the files using the File Combine functionality for CSV, XLSX, PDF, and other flat files.

[amitchandak · Accepted solution]

@PBI_newuser ,

refer

https://www.thebiccountant.com/2017/01/11/incremental-load-in-powerbi-using-dax-union/

https://blog.crossjoin.co.uk/2020/04/13/keep-the-existing-data-in-your-power-bi-dataset-and-add-new-...

[PBI_newuser]

Hi @amitchandak ,

The old data can be stored, but once i made some changes in pbix file and publish it again, all the old data has gone.

How can I solve this?

[edhans]

@PBI_newuser That was why I said you cannot efficiently do this in Power BI. There are hacks and tricks, but this is not a robust solution. To save data, you need to get the ALM Toolkit.

All of this is really meant for very VERY large datasets where you don't want to push the data up with every sync. The trick that Christopher Webb shows on his blog is really cool, but as you can see, it is not sustaninable without a lot of extra work on your part to keep both sets of data there in the event of a republish.

My advice stands as before. Find a workflow that can properly store data for prior periods.

But if you want to continue down this path, get the ALM Toolkit mentioned above and start reading through that material on how to manage data already stored in the service and avoid overwriting it.