Informatica Interview Questions Answers Page 1

2/27/2010 No Comment

Data Warehousing Interview Questions, Informatica Interview Questions and Answers.

What is the dissimilarity between the start and abort?
There are various session in one batch. If you want to stop a session which is a part of a batch then you will have to use the stop command. If the batch is nested in another batch then you will have to stop the outer most batches. The abort function provides the time out of 60 second. If the processor or the server is not able to finish the job during this time then it will be automatically aborted.

How to delete duplicate record in Informatica
Ans :
Following are ways to remove duplicate records
1. In source qualifier use select distinct
2. Use Aggregator and group by all fields
3. Override SQL query in Source qualifier

What is DTM process?
After the load manger performs validations for session, it creates the DTM process. DTM is to create and manage the threads that carry out the session tasks. Master thread creates and manages all the other threads.

What are the data movement modes in Informatica?
Data movement modes determine how Informatica server handles the character data. U choose the data movement in the Informatica server configuration settings.
Two types of data movement modes available in Informatica. ASCII mode Unicode mode

Why do we use the lookup transformation? How can we improve session performance in aggregator transformation?
A lookup transformation is used for checking the matched values from the source or target tables and check whether the record already existing in the table. It is also used for updating the slowly changing dimensions and also performs some calculations.
Using Incremental Aggregation we create Sorted Input option to improve the performance since performance is reduced using the caches.

What are the types of metadata that stores in repository?
Following are the types of metadata that is stored in the repository.
Database connections, Global objects, Mappings, Mapplets, Multidimensional metadata, Reusable transformations, Sessions and batches, Short cuts, Source definitions, Target definitions, Transformations

Where should you place the flat file to import the flat file definition to the designer?
Place it in local folder.

To provide support for Mainframes source data, which files are used as a source definitions?
COBOL files

Which transformation should you need while using the Cobol sources as source definitions?
Normalizer transformation which is used to normalize the data. Since COBOL sources are often consists of Demnormalized data.

How can you create or import flat file definition in to the warehouse designer?
You can not create or import flat file definition in to warehouse designer directly. Instead of that you must analyze the file in source analyzer and then drag it into the warehouse designer. When you drag the flat file source definition into warehouse designer workspace, the warehouse designer creates a relational target definition not a file definition. If you want to load to a file, configure the session to write to a flat file. When the informatica server runs the session, it creates and loads the flat file.

What is incremental aggregation?
When using incremental aggregation, you apply captured changes in the source to aggregate calculations in a session. If the source changes only incrementally and you can capture changes, you can configure the session to process only those changes. This allows the Informatica Server to update your target incrementally, rather than forcing it to process the entire source and recalculate the same calculations each time you run the session.

What is throughput in Informatica? Where can we find this option to check? How does it works?
Throughput is the rate at which power centre server read the rows in bytes from source or write the rows in bytes into the target per second.We can find this option in workflow monitor.Its working is as follows: right click on session choose properties and transformation statistics tab, there we can find throughput details for each instance of source and target.

Under what circumstances does informatica server create Reject files?
1.When it encounters the DD_Reject in update strategy transformation.
2.Violates database constraint in the rows (truncated or overflowed)
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