Live connection limitations

[MiaOlly]

Hi,

In Power BI Desktop, I am not able to create the calculated columns/table when use live connectio with a semantic model that already exists in Power BI service. See below:

While when i review the document here:https://learn.microsoft.com/en-us/power-bi/connect-data/desktop-report-lifecycle-datasets#considerat...

It mentioned that:"You can only create measures (Report Measures), calculated columns, visual calculations and calculated tables."

Can someone help me to explain it? Thank you!

[rajendraongole1]

Hi @MiaOlly - You can create measures, visual calculations, and some report-level measures.However, you cannot create calculated columns or calculated tables in Power BI Desktop if you're using a live connection. you connect directly to a pre-existing semantic model. This means you are limited in how much you can modify the data model.

The documentation you referenced mentions measures, visual calculations, and calculated tables in the context of Power BI Service direct queries or composite models, which allow more flexibility. However, in a strictly live connection to an existing semantic model, these modifications are limited.

Let me know if you have more questions about working within these limitations!

[MiaOlly]

Thanks so much! That helps a lot. Can I ask you another question? I find in composite model, sometimes the calculated table/column works and sometimes are not. for example, when only referring to one data source and DAX syntax is not complex, it works sometimes. While when calculated columns/tables refer to two or more tables with relative complex DAX syntax, it does not work. Can you please shed more light on it? Which situation works and which are not? Here are some error codes I got when it is not working.

[rajendraongole1 · Accepted solution]

Hi @MiaOlly - As mentioned, Calculated columns and tables can behave differently based on the type and number of data sources referenced. If you are combining tables from multiple sources or have different types of storage modes (DirectQuery and Import), limitations may arise. For instance:

Single Source: Calculated tables and columns typically work well if you’re referencing only one data source, especially in Import mode.
Multiple Sources: If your calculation involves tables from multiple sources, particularly in DirectQuery mode, you might encounter restrictions due to differences in how each data source handles DAX expressions and relationships.

The error message you shared, "This semantic model contains calculated tables or calculated columns that refer to remote tables," highlights that calculated columns/tables referencing remote sources require explicit permissions and granular access configurations, especially when using DirectQuery connections.

Sometimes, you may see errors such as refresh failures or messages about unsupported operations. These are usually due to Power BI's limitations on combining complex DAX calculations across tables in composite models, as well as refresh constraints for calculated tables/columns in DirectQuery.