Question on data flows in Power BI service

[Anonymous]

Hi All,

I need to create a visual that uses several database sources (sql server, oracle, and impala). When I build some of the sources, I need to retrieve data based off another table. At a very high level, I’ll pull records from TableA. TableB will be populated using separate logic and only if customerid is in TableA is in TableB. I would do this in a query, but the data isn’t in the same database. I did some googling, and the best way to approach this is through a dataflow, but before I proceed, I wanted to make sure that I can create a dataflow and Publish my visual. If you have any suggestions on how to accomplish this in PowerBI, please let me know. Lastly, as I understand it, a dataflow will eliminate calls to the database every time the visual is viewed. A call will be made to the database only when the data is refreshed. Is that correct?

Thanks in advance!

[ichavarria · Accepted solution]

Hi @Anonymous,

Yes, you can create a dataflow in Power BI to combine data from multiple sources, including SQL Server, Oracle, and Impala. In your case, you can create two entities, one for each table, and establish a relationship between them based on the customer ID column. You can then use the dataflow in your visualizations.

Before publishing your visual, you need to ensure that the dataflow is scheduled to refresh at the appropriate intervals, so your data is always up to date. You can schedule the refresh in the Power BI service.

Regarding your question about dataflow, yes, you are correct. Dataflows in Power BI cache the data and only refresh it when needed, such as when the dataflow is refreshed or when a report that uses the dataflow is refreshed. This helps to reduce the number of calls to the data source and improve performance.

Best regards, 

Isaac Chavarria

If this post helps, then please consider Accepting it as the solution and giving Kudos to help the other members find it more quickly.