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Sample Interview Questions for SSIS jobs

  • 5 April 2010
  • Author: kylewalker
  • Number of views: 13391

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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