Informatica Job Interview Questions Answers

2/13/2010 No Comment

Informatica Job Interview Questions Answers.

DataWarehousing Informatica Interview Questions to make you Proficient in all aspects of Informatica and related DataWarehousing tools.

Explain what are the joiner caches in Informatica?
When there is a Joiner transformation that occurs in a session, the Informatica Server will reads all the records from the master source and build index and data caches based on the master rows. After building of the caches, the Joiner transformations reads records from the detail source and perform join operation.

Explain about look up transformation?
We can use lookup transformation in our mappings to lookup data in a relational table, view, and synonym. Informatica server queries the look up table based on the lookup ports in the transformation. It compares the lookup transformation port values to lookup table column values based on the look up condition.

How do you find all invalid mappings in a folder in Informatica?
 By using the query cited below.

Explain what are the data movement modes available in Informatica?
Ans :
Data movement modes determines how power center server handles the character data. We choose the data movement in the Informatica server configuration settings. Two types of data movement modes available in Informatica.
1.ASCII mode
2.Unicode mode.

Can you use the mapping parameters or variables created in one mapping into another mapping?
Ans :
NO. We can use mapping parameters or variables in any transformation of the same mapping or mapplet in which you have created mapping parameters or variables.

Can you use the mapping parameters or variables created in one mapping into any other reusable transformation?
Ans :
Yes. Because reusable transformation is not contained with any mapplet or mapping.

How can you improve session performance in aggregator tansformation?
Ans :
Use sorted input.

What is aggregate cache in aggregator transformation?
Ans :
The aggregator stores data in the aggregate cache until it completes aggregate calculations. When you run a session that uses an aggregator transformation, the informatica server creates index and data caches in memory to process the transformation. If the informatica server requires more space, it stores overflow values in cache files.

What are Limitations on joiner transformation ?
Ans :
1.Both pipelines begin with the same original data source.
2.Both input pipelines originate from the same Source Qualifier transformation.
3.Both input pipelines originate from the same Normalizer transformation.
4.Both input pipelines originate from the same Joiner transformation.
5.Either input pipelines contains an Update Strategy transformation.
6.Either input pipelines contains a Sequence Generator transformation.

What will happen if we connect only current value port from seq generator to next transformation (without connecting nextval)
Ans :
Each target will get the value 1.

What do you mean by code page compatibility?
Ans :
When two code pages are compatible, the characters encoded in the two code pages are virtually identical which ensures no data loss. This compatibility is used for accurate data movement when the Informatica Sever runs in the Unicode data movement mode. One code page can be a subset or superset of another. For proper data movement, the target code page must be a superset of the source code page.

What is difference between partitioning of relational target and partitioning of file targets?
Ans :
If you partition a session with a relational target Informatica server creates multiple connections to the target database to write target data concurrently. If you partition a session with a file target the Informatica server creates one target file for each partition. You can configure session properties to merge these target files.

What are the transformations that restricts the partitioning of sessions?
Ans :
Advanced External procedure transformation and External procedure transformation: This transformation contains a check box on the properties tab to allow partitioning.
Aggregator Transformation: If you use sorted ports you can not partition the associated source
Joiner Transformation: you can not partition the master source for a joiner transformation .Normalizer Transformation XML targets.
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