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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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Sample Interview Questions for SSIS jobs

  • 5 April 2010
  • Author: kylewalker
  • Number of views: 11800

I don't know about you, but for some reason, one of the most terrifying experiences for me is interviewing for a new job.  There are a few things that you can do to prepare yourself for an upcoming interview and make it slightly less terrifying.  You can work on improving your communication skills and managing whatever nervous habits you may have developed over the years.  Or spend some time thinking of some questions that you would like to ask your hopefully-soon-to-be employer, so that when they ask you, "so, do you have any questions for us?", you can say something other than "nope, I'm good" ("Nope, I'm good" isn't a very impressive response... Just ask all of your unemployed friends.  Try to always ask at least one question about the job you'll be doing or the environment you'll be working in).  The most ideal preparation aide (not H) would be having a cheat sheet or a list of the questions that you will be asked in the interview.  Well here's the best I can do for you.  Here are some real-world questions that I have encountered while interviewing for SSIS specific jobs.  (Along with some answers)

Explain the difference between Synchronous and Asynchronous components.  A synchronous component will reuse the input buffer because the number of output rows is exactly the same as the number of input rows.  This basically means that a synchronous component can start before the previous component completes.  With an asynchronous component, a new buffer is used because there can be a different number of output rows than input rows.  And this means that in some cases the component may need to wait for the previous component to fully complete before it can even start.

What can you use an OLE DB Command for?  The OLE DB Command is a pretty simple transformation that's available within a Data Flow that can run a SQL statement that can insert, update, or delete records to, in, or from a desired table.  It's good to keep in mind that this transformation initiates a row-by-row operation, so you may experience some performance limitations when dealing with large amounts of data.

What are checkpoints and why are they important?  Checkpoints offer the ability to restart failed package at a specified point.  If you have configured a checkpoint on a package, information about that package will be sent to a checkpoint file.  In the event of a failure, the package will use this information to know where to start.  In the event of a successful completion, this file is automatically deleted.

What are the benefits or advantages of using Raw Files in ETL?  Aside from the possibly that a Raw File might be your only option as a source.  Raw files do offer a slightly better advantage when it comes to speed and performance.

What is a Common Table Expression?  A common table expression is basically a result set that is temporarily stored within the scope of a SELECT, UPDATE, INSERT, or DELETE statement.  The data stored from the common table expression can be used by the SQL statement that follows it.

What can you tell me about Ralph Kimball?  Ralph Kimball is an author on the topic of data warehousing and BI.  He has been regarded as one of the original architects of data warehousing.  Kimball has always had the firm belief that data warehouses should fast and understandable.  Oh, and he developed this whole methodology of dimensional modeling.  There is that.  (It's also probably a good idea to know the basic idea and structure of dimensional modeling)

I hope this helps as you prepare for your next SSIS interview!  Good luck!

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