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«November 2015»

DirectQuery in Power BI Desktop

In the latest Power BI Desktop a new Preview features was released that now allows you to connect using DirectQuery to either SQL Server or Azure SQL Databases.  DirectQuery is a really neat feature that allows you to point to the live version of the data source rather than importing the data into a data model in Power BI Desktop. 

Normally when you want to get an updated dataset in the Power BI Desktop you would have to manually click the refresh button (this can be automated in the Power BI Service), which would initiate a full reimport of your data.  This refresh could take a variable amount of time depending on how much data your have.  For instance, if you’re refreshing a very large table you may be waiting quite a while to see the newly added data. 

With DirectQuery data imports are not required because you’re always looking at a live version of the data.  Let me show you how it works!

Turning on the DirectQuery Preview

Now, because DirectQuery is still in Preview you must first activate the feature by navigating to File->Options and settings->Options->Preview Features then check DirectQuery for SQL Server and Azure SQL Database


Once you click OK you may be prompted to restart the Power BI Desktop to utilize the feature.

Using DirectQuery in Power BI Desktop

Next make a connection either to an On-Premises SQL Server or Azure SQL database.

Go to the Home ribbon and select Get Data then SQL Server.


Provide your Server and Database names then click OK. ***Do not use a SQL statement.  It is not currently supported with DirectQuery***


From the Navigator pane choose the table(s) you would like to use.  I’m just going to pick the DimProduct table for this example and then click Load.  You could select Edit and that would launch the Query Editor where you could manipulate the extract.  This would allow you to add any business rules needed to the data before visualizing it.


Next you will be prompted to select what you want to connect to the data. Again, Import means the data

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The Big Data Blog Series

Over the last few years I’ve been speaking a lot on the subject of Big Data. I started by giving an intermediate session called “Show Me Whatcha’ Workin’ With”. This session was designed for people who had attended a one hour introductory session that showed you how to load data, to look at possible applications … Continue reading The Big Data Blog Series
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SSRS 2008 R2: Show Column Meta-Data in ToolTip

First, I want to apologize to the three people that read my blog. Sorry for going dark for such a long period of time. I am not going to commit to writing on a regular basis just yet, but I will be back consistently soon. Enough about me, let’s talk about the problem at hand. Recently, someone asked if it was possible to show column information (description, data type, etc…) in a tooltip. I never really gave that scenario much thought until I was posed with the question. So, is it possible in SSRS 2008 R2? The answer is, not natively. However, it can be done with a little effort.

Report Code

Assuming you have already created your report, the first step is to add some custom code to your report. To do this click Report on the menu bar and select Report Properties. The Report Properties dialogue window will open.

Select the item labeled Code in the left section of the window. In the textbox labeled Custom Code, type your code. In the above image I included a VB code snippet that accepts two parameters, ColumnName and TableName. The code executes a query that returns the data type for the column/table combination. The statement could be modified to query a Meta data repository that contains more descriptive information about your column. For the sake of brevity I am querying the information_schema.columns table. Once you have written your custom code, the next step is to add a reference to the System.Data assembly. To do this, select References in the left section of the Report Properties window.

Next click the button labeled Add under Add or remove assemblies. Click the Ellipses button located to the newly added textbox and the Add Reference dialogue window will open.

Ensure that the .NET tab is selected, scroll down the list until you see System.Data. Select it and click OK.

The ToolTip

With all of the plumbing in place, now it’s time write the expression that will execute the code and render the tooltip. Since the requirement is to surface information about columns in the data set I will be adding an expression to the tooltip for each column header in the table on my report. To quickly apply the expression to each column, select every applicable column header in your table and press the F4 key, which opens the Properties window. Locate the ToolTip option, click in the field, select the drop down arrow and choose Expression. In the expression window type the following:

=Code.GetMetaData(Replace(ReportItems!Textbox5.Value,” “,“”), “Product”)

As mentioned above, the function accepts two parameters. The first is the value of that is displayed in the column header. Since SSRS automatically adds a space to column names that contain upper case letters, I used the Replace function to remove the spaces. One caveat about this approach is that if you customize the column header names you will need to explicitly include the column name in the expression instead of the code that I have include for the first parameter. The second value is the table name. You could further extend this to include the schema name also.


After all that I really really really thought I was done. So, I ran the report and when I hovered over my column headers nothing happened. To be honest, I had no idea what to do. After a few minutes of thinking I remember that there was an Output window available when you ran reports. I clicked View on the menu bar and selected Output, and there was my error:

‘Textbox5′ contains an error: Request for the permission of type ‘System.Data.SqlClient.SqlClientPermission, System.Data, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089′ failed.

Since I am not much of a .Net developer, I was still pretty lost. I decided to start searching the Internet. I found a few articles that evenutally led me a config file that needed to be modified. While I was pointed to the correct file, neither of documents provided me with the specific solution. After making a few changes and a few undo’s my report ran successful.

In this directory, C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies, open the RSPreviewPolicy file. Locate the first CodeGroup section, which will be directly below the closing NamedPermissionSets tag, change the PermissionSetName attribute to FullTrust and save the file. You may want to make a copy of the file prior to changing and saving it.

After this change has been made, save the file and preview your report, which should run now.

If you have a better solution for this, please send me an email at Also, if something does not work send me an email. Thanks for reading.

Talk to you soon,

Patrick LeBlanc

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