Archive for November, 2006

Informatica interview questions & FAQs

Tuesday, November 21st, 2006
What is a source qualifier?
What is a surrogate key?
What is difference between Mapplet and reusable transformation?
What is DTM session?
What is a Mapplet?
What is a look up function? What is default transformation for the look up function?
What is difference between a connected look up and unconnected look up?
What is up date strategy and what are the options for update strategy?
What is subject area?
What is the difference between truncate and delete statements?
What kind of Update strategies are normally used (Type 1, 2 & 3) & what are the differences?
What is the exact syntax of an update strategy?
What are bitmap indexes and how and why are they used?
What is bulk bind? How does it improve performance?
What are the different ways to filter rows using Informatica transformations?
What is referential Integrity error? How do you rectify it?
What is DTM process?
What is target load order?
What exactly is a shortcut and how do you use it?
What is a shared folder?
What are the different transformations where you can use a SQL override?
What is the difference between a Bulk and Normal mode and where exactly is it defined?
What is the difference between Local & Global repository?
What are data driven sessions?
What are the common errors while running a Informatica session?
What are worklets and what is their use?
What is change data capture?
What exactly is tracing level?
What is the difference between constraints based load ordering and target load plan?
What is a deployment group and what is its use?
When and how a partition is defined using Informatica?
How do you improve performance in an Update strategy?
How do you validate all the mappings in the repository at once?
How can you join two or more tables without using the source qualifier override SQL or a Joiner transformation?
How can you define a transformation? What are different types of transformations in Informatica?
How many repositories can be created in Informatica?
How many minimum groups can be defined in a Router transformation?
How do you define partitions in Informatica?
How can you improve performance in an Aggregator transformation?
How does the Informatica know that the input is sorted?
How many worklets can be defined within a workflow?
How do you define a parameter file? Give an example of its use.
If you join two or more tables and then pull out about two columns from each table into the source qualifier and then just pull out one column from the source qualifier into an Expression transformation and then do a ‘generate SQL’ in the source qualifier how many columns will show up in the generated SQL.
In a Type 1 mapping with one source and one target table what is the minimum number of update strategy transformations to be used?
At what levels can you define parameter files and what is the order?
In a session log file where can you find the reader and the writer details?
For joining three heterogeneous tables how many joiner transformations are required?
Can you look up a flat file using Informatica?
While running a session what default files are created?
Describe the use of Materialized views and how are they different from a normal view.

Contributed by Mukherjee, Saibal (ETL Consultant)

Many readers are asking “Where’s the answer?” Well it will take some time before I get time to write it… But there is no reason to get upset… The informatica help files should have all of these answers! :-)

ETLGuru.com: ETL Strategies and Solutions for Data Warehouse……..ETL book by Sandesh Gawande

Friday, November 3rd, 2006

Ok! I am finally planning to publish ETL book with detailed information on all aspects related to ETL and Data Integration. The ETL Book will be used by Data Warehouse Managers, Data Warehouse Architects & ETL Leads. It will also contain solutions for ETL developers. The Book will be independent of ETL tools like Informatica, DataStage, etc.

The good news is that readers will not have to wait for the completion of all chapters. I will make individual completed chapters available so that readers do not have to wait for others to be complete. Once all the chapters are complete readers can return individual chapters and get complete ETL Book free or paying the difference. The ETL forum will have a thread for each chapter so that reader can discuss/ recommend/ suggest. This will make it a complete ETL package.

Comments welcome! Like on chapters, title of the book, what you would like see in the contents, etc. I will also offer money back guarantee if you dislike the book.  For competing ETL books, I would suggest you buy it (The Data Warehouse ETL Toolkit) only if the bookstore near you permits for returns, so that you can compare yourself and decide.

Please wait for link to purchase ETLGuru.com Book /Chapters… Coming soon… First few chapters before Nov 30 2006.  Dec 30 2006.