4/11/16

Informatica Interview Questions and answers for Experienced

Question.1  What is the difference between connected and unconnected transformation?

Answer:   Connected Transformation: Connected transformation is connected to other transformations or directly to target table in the mapping. Unconnected Transformation: An unconnected transformation is not connected to other transformations in the mapping. It is called within another transformation, and returns a value to that transformation.
Question.2   What are various types of Aggregation?
Answer:
Various types of aggregation are
SUM
AVG
vCOUNT
MAX
MIN
FIRST
LAST
MEDIAN
PERCENTILE
STDDEV
VARIANCE. [sociallocker]
Question.3   What are Aggregator Transformation?
Answer:   Aggregator transformation is an Active and Connected transformation. This transformation is useful to perform calculations such as averages and sums (mainly to perform calculations on multiple rows or groups).
Question.4   What are Expression transformation?
Answer:    Expression transformation is a Passive and Connected transformation. This can be used to calculate values in a single row before writing to the target.
Question.5   What are Filter transformation?
Answer:    Filter transformation is an Active and Connected transformation. This can be used to filter rows in a mapping that do not meet the condition.
Question.6   What are Joiner transformation?
Answer:   Joiner Transformation is an Active and Connected transformation. This can be used to join two sources coming from two different locations or from same location.
Question.7   Why we use lookup transformations?
Answer:   Lookup Transformations can access data from relational tables that are not sources in mapping.
Question.8   What are Normalizer transformation?
Answer:    Normalizer Transformation is an Active and Connected transformation. It is used mainly with COBOL sources where most of the time data is stored in denormalized format. Also, Normalizer transformation can be used to create multiple rows from a single row of data.
Question.9    What are Rank transformation?
Answer:   Rank transformation is an Active and Connected transformation. It is used to select the top or bottom rank of data.
Question.10   What are Router transformation?
Answer:    Router transformationis an Active and Connected transformation. It is similar to filter transformation. The only difference is, filter transformation drops the data that do not meet the condition whereas router has an option to capture the data that do not meet the condition. It is useful to test multiple conditions.
Question.11   What are Sorter transformation?
Answer:   Sorter transformation is a Connected and an Active transformation. It allows to sort data either in ascending or descending order according to a specified field.
Question.12   Name four output files that information server creates during session running?
Answer:
Session Log
Workflow Log
Errors Log
Badfile
Question.13   What is the difference between lookup cache and lookup index?
Answer:
Look up Cache contains Index cache and data cache.
Index cache : Contains columns used in condition.           
Question.14   What are the difference between static cache and dynamic cache?
Answer:   Dynamic cache decreases the performance in comparisons to static cache.
Static cache do not see such things just insert data as many times as it is coming.
Question.15    Define maping and sessions?
Answer:   Maping: It is a set of source and target definitions linked by transformation objects that define the rules for transformation.  Session : It is a set of instructions that describe how and when to move data from source to targets.
Question.16    What is a command that used to run a batch?
Answer:   pmcmd is used to start a batch.
Question.17   What is Datadriven?
Answer:   The informatica server follows instructions coded into update strategy transformations with in the session maping determine how to flag records for insert, update, delete or reject.
Question.18   What is power center repository?
Answer:      The Power Center repository allows you to share metadata across repositories to create a data mart domain.
Question.19   What is parameter file?
Answer:   A parameter file is a file created by text editor such as word pad or notepad. U can define the following values in parameter file.
Maping parameters
Maping variables
session parameters