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Naturally you want the reports that you publish to Power BI Service to be up to date, but the rules are fiendishly complex. This blog explains when and how to create the two types of gateway, and how to ensure your reports refresh.
- Getting Power BI Service reports to refresh
- How Power BI connections work (this blog)
- How connections work for Direct Query
- Setting up a personal gateway to allow data to refresh
- Creating an on-premises data gateway for everyone to use
- Gateway requirements, limitations and troubleshooting
- Manual and scheduled refreshing of data
- Refreshing data within the cloud (Azure, OneDrive)
This blog is part of a longer series, which together comprise a full online training course in Power BI Service. You can see get details of our classsrom Power BI training courses here.
Posted by Andy Brown on 03 July 2017
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How Power BI connections work
To understand how refreshing works in Power BI, you have to have a clear understanding of the connections involved. Let's look firstly at what happens when you create and publish report, then at the connections created and used.
How Power BI Reports Work
In a PBIX report, you import data from databases or files (in my case, from two files - one Excel workbook, and one CSV text file):

I've deleted some columns from the data model, and renamed others.
You then extract data from this simplified data model to create a report:

Thus the report gets its data from the data model, and the data model gets its data from the underlying data source (in this case an Excel workbook and a CSV file, but this could equally well be a SQL Server or other database).
When you publish this report, you get two things in Power BI Service - a report and its associated dataset:

I've got a report and a dataset, both called Simple report.
Here's a diagram of what's involved (Power BI Desktop is on the left, Power BI Service on the right):

Note that in Power BI Service you can't actually see the relationships as shown above.
So far, so good - now let's have a look at what connections are involved in this diagram.
The connections used for Power BI reports, and how refreshing works
So what it comes down to is this. In the Power BI Desktop report (the left side), you have a connection:

This connection knows which files to look for, and where, and also contains any security settings needed.
A typical connection specifies four things (the settings for our two files are shown as examples):
What | Courses CSV file | Delegates Excel workbook |
---|---|---|
The type of file | Text (comma-separated values) | Excel |
Where to find file | A folder called wiseowl on the C drive | |
File name | Courses.csv | Delegates.xlsx |
Security permissions | No user name or password needed |
And finally, we get to the problem. Here's what the published report has to do to refresh:

The published report is irrelevant. It's the dataset which has to refresh, by somehow using a published version of the connection created in the desktop file to link to the underlying data files or databases.
So refreshing is all about how to get data across the vertical green line above, using the same connection settings as for the desktop report.
- Getting Power BI Service reports to refresh
- How Power BI connections work (this blog)
- How connections work for Direct Query
- Setting up a personal gateway to allow data to refresh
- Creating an on-premises data gateway for everyone to use
- Gateway requirements, limitations and troubleshooting
- Manual and scheduled refreshing of data
- Refreshing data within the cloud (Azure, OneDrive)