Archive for the ‘Informatica FAQs’ Category

Informatica FAQ’s Additional

Monday, October 22nd, 2007

What are the different types of Lookups?
The different types of lookups are static Lookup, dynamic lookup, static persistent Lookup 

What is Test Load in informatica?
If we want to test the execution of the mapping without loading any data in the target database
then we check the option of test load.

Why is parameterization imp and how does it help?
Parameterization helps us to avoid making changes in the mappings in case any of the variables in the
mapping have undergone change. By putting values that are likely to change in parameter file(Like schema name,
Update user_id) we improve maintainability of the code. 

Is there any advantage of having less number of Transformations in a mapping?
More Transformations mean increased time of execution for a mapping as the data has to be
passed thru another process of Transformation.

What is the overhead in a dynamic lookup over a static lookup?
As the dynamic lookup can undergo change in its values as the mapping is currently executing
hence PowerCenter has to continuously look for changes that are likely to happen. This causes additional overhead. 

What is the advantage of sending sorted data into a joiner transformation?
When sorted data is sent thru a joiner Transformation, we can take advantage of the sorted input option
available in Joiner. This causes the join operation to take less time than otherwise.

Is it possible to have a mapping with update strategy, using bulk mode?
No, Update strategy can be executed only in Normal mode. 

How can a mapping be failed if the numbers of rejects are more than a certain threshold?
Session option abort on error offers us the number of errors before which the session will be aborted.
By default it is zero. 
By Sujith Nair

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! :-)