Using Parameter Tables To Control Data Refresh In Power BI

The use of parameter tables is a well-known technique in Power Query. It involves using a table from the current Excel workbook to hold various parameter values that are read using a Power Query query, and these parameter values are then passed to another Power Query query to control how it behaves. Ken Puls has a great post describing all this here, and similarly a lot of the demos in my video on on building a reporting solution in Power Query involve reading values from a table which are then used to filter data in a SQL query.

The problem with Power BI Desktop and PowerBI.com is that without a current Excel workbook there’s nowhere to store parameter values (at least at the moment) so you can’t implement the technique in exactly the same way. However, with a bit of creativity, it is possible to do something very similar.

Consider the following M query that gets all the rows from the DimDate table in the Adventure Works DW SQL Server database where the day name is Tuesday.

let
    Source = Sql.Database("localhost", "adventure works dw"),
    dbo_DimDate = Source{[Schema="dbo",Item="DimDate"]}[Data],
    #"Filtered Rows" = Table.SelectRows(
     dbo_DimDate, 
     each ([EnglishDayNameOfWeek] = "Tuesday"))
in
    #"Filtered Rows"

From this you can build a report in Power BI Desktop that looks something like this:

image

The question is, in this case, how can you make this dynamic and allow your end users to enter a different day name to filter by, and how can you ensure that this dynamic filtering works even when the report has been deployed to PowerBI.com?

There may not be a current workbook to store parameters but in PowerBI.com you can of course display Excel workbooks stored in OneDrive for Business as reports (full details on how to do this are here). Rather than display an Excel report, you can instead display a workbook containing an Excel table containing a day name:

image

This is going to be your parameter table. First minor irritation: while it seems like you can change the value in the table inside PowerBI.com the value doesn’t get saved; you have to use the Edit option to open the workbook in Excel Online before any changes you make do get saved.

image

image

The next problem is this: how can you read the day name parameter value from a table stored in an Excel workbook in OneDrive For Business? It’s actually possible using the Excel Services OData API and I blogged about how to call this API in Power Pivot a few years ago here. With a workbook called FilterParameter.xlsx and an Excel table called FilterDay, here’s an example M query that reads the day name parameter value:

let
    Source = OData.Feed("https://enteryourdomainhere-my.sharepoint.com/_vti_bin/ExcelRest.aspx/personal/chris_enteryourdomainhere_onmicrosoft_com/Documents/FilterParameter.xlsx/OData/FilterDay"),
    #"0" = Source{[excelRowID=0]}[Enterparametervalue]
in
    #"0"

If this M query is called DayFilter, then the value it returns can be used in the original query to make the filter dynamic (you will also need to set your data privacy levels correctly or enable Fast Combine):

let
    Source = Sql.Database("chriszbook", "adventure works dw"),
    dbo_DimDate = Source{[Schema="dbo",Item="DimDate"]}[Data],
    #"Filtered Rows" = Table.SelectRows(
     dbo_DimDate, 
     each ([EnglishDayNameOfWeek] = DayFilter))
in
    #"Filtered Rows"

image

At this point you’ll have something that works in Power BI Desktop, but there’s still more to do to make this work after the report has been published to PowerBI.com. For a start you’ll need to make sure you’re using the latest version of the Power BI Personal Gateway and that you have enabled Fast Combine in it by following the instructions in this blog post. You also need to make sure that in PowerBI.com, when you set up the credentials for the OData connection to the Excel table, you use the OAuth2 Authenication Method option:

image

And with that, you’re done. You can edit the Excel workbook to change the day name that you want to filter by, and to refresh your report in PowerBI.com you can use the Refresh Now option on the dataset:

image

While dashboards reflect the updated data automatically, if you’re looking at a report you may also need to use the Refresh button on the top of the report to see updated data:

image

And there you have it: a parameter table in PowerBI.com. To be honest, I think there are slightly too many fiddly steps for users to follow in this technique for me to be happy recommending its use unconditionally, but it should be useful in some scenarios. Hopefully there will be an easier way of accomplishing the same thing in Power BI in future…

14 thoughts on “Using Parameter Tables To Control Data Refresh In Power BI

  1. I failed to import excel table in a workbook I uploaded to our office 365 site (business one drive) into power bi desktop. any advise on this?

    • It’s quite tricky to find the URL you need to use for the workbook, unfortunately. If you’re using OneDrive for Business it should be roughly the same URL as the one I show in my example, but remember to use your domain, include the correct folder structure, workbook name and table name.

  2. Hi Chris,

    Great post – The parameter tables were the first thing I noticed were missing in the Power BI desktop version when I started using it. I always use them for dynamic calendar tables and file paths.

    I was looking on the Power BI idea forums for a ‘Parameter Table’ idea and all I could find were these ideas:

    https://ideas.powerbi.com/forums/265200-power-bi/suggestions/10859529-user-defined-parameter-tables

    https://ideas.powerbi.com/forums/265200-power-bi/suggestions/9665565-support-relative-path-to-excel-csv-sources

    Seems pretty vague and doesn’t have many votes / interest, despite this being an important issue from my perspective. Do you know if this is on the Microsoft’s roadmap?

    If not, I encourage everyone to vote for one or both of these ideas!

  3. Dear Chris,
    Thank Very Very much for your work. We really appreciate your great posts and books very much.

    The problem we are encountering is that while Power BI Desktop refreshs data perfectly with parameteric Power Queries, Power BI online does not give the option to refresh, and it doesn’t detect the source of data.

    We have created a query with a SQL access defined by a parameter such as:
    Query1
    let
    servername = () =>
    let
    Origen = “XXXXX.database.windows.net”
    in
    Origen
    in
    servername

    Query2
    a=Query1()
    Origen = Sql.Database(a, “ASFdataXXX”, [Query=”select * FROM leads”])
    in
    Origen

    We guest it is related to the folding process.

    • Do you know if there is such problem of the Power Query Desktop + Power BI Online?
    • Do you know any workaround to get a parametric SQL or how to get a parametric SQL source just using UI?

    Thank you very beforehand much for your time and interest.
    Best Regards,

  4. I’m well late in the day posting to this but there are now Parameters in addition to Queries in Power BI. This is an extremely useful feature where you can house parameter values and even set validation for them for ease of maintenance. However, I still import a parameters table because I want to keep the final user away from setting parameter values in PBI desktop given the propensity to screw up. So I use the new feature more from a developer perspective

    • Don’t forget that, at least at the moment, there’s no way to use parameters in PowerBI.com after the report has been published so this technique is still valid. Eventually though, parameters will be the replacement for this technique, you’re right. I have already blogged about them several times🙂

      • No probs, I missed those but will have time to catch up on your blogs very soon. Any plans on a new book along lines of ‘The Definitive Guide to M’ ?! I would definitely buy it 😀

      • There’s definitely a vacuum for an authoritative text on M, writing efficient queries, what constitutes expensive queries etc. The power query formula guide with scant examples just isn’t enough for anyone who wants to go beyond the standard ribbon clicks. You know it makes sense 😉

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