Friday, November 14, 2008

Informatica Interview Questions And Answers VI

What are the types of groups in Router transformation?
Input group Output group
The designer copies property information from the input ports of the input group to create a set of output ports for each output group.
Two types of output groups:-
User defined groups
Default group.
You can not modify or delete default groups.
What is the default join that source qualifier provides?
Inner equi join.
Define informatica repository?
Infromatica Repository:The informatica repository is at the center of the informatica suite. You create a set of metadata tables within the repository database that the informatica application and tools access. The informatica client and server access the repository to save and retrieve metadata.
Which tool U use to create and manage sessions and batches and to monitor and stop the informatica server?
Informatica Workflow Managar and Informatica Worlflow Monitor
How to define Informatica server?
Informatica server is the main server component in informatica product family..Which is resonsible for reads the data from various source system and tranforms the data according to business rule and loads the data into the target table
Explain the informatica Architecture in detail

informatica server connects source data and target data using native

odbc drivers

again it connect to the repository for running sessions and retriveing metadata information

source------>informatica server--------->target



I was working in SQL server, now i got an golden opertunity to work in INFORMATICA. I have lots of (silly) Questions to build my Career, so pls guide me properly. I will ask lots of questions....

What is the process flow of informatica,
Informatica is a ETL tool.used for the Extraction,Transformation and Loadind of data.This tool is used to Extract the data from different Data Bases and then we can do the required transfermation like data type conversions,doing some aggregations,ordering,filtering and so on.After that we can load the transformed data into our database,which will be used for the Bussiness Decissions.
Can anyone explain about incremental aggregation with an example?
Incremental aggregation is specially used for tune the performance of the aggregator. It captures the change each time (incrementally) you run the transformation and then performs the aggregation function to the changed rows and not to the entire rows. This improves the performance because you are not reading the entire source, each time you run the session.
How can you recognise whether or not the newly added rows in the source are gets insert in the target?
In the Type2 maping we have three options to recognise the newly added rows
Version number
Effective date Range.
What is difference between dimention table and fact table
and what are different dimention tables and fact tables

In the fact table contain measurable data and less columns and meny rows,

It's contain primarykey

Diffrent types of fact tables:

additive,non additive, semi additive

In the dimensions table contain textual descrption of data and also contain meny columns,less rows

Its contain primary key
How to export mappings to the production environment?
In the designer go to the main menu and one can see the export/import options.

Import the exported mapping in to the production repository with replace options.
When do u use a unconnected lookup and connected lookup....

what is the difference between dynamic and static lookup...y and when do v use these types of lookups ( ie...dynamic and static )
In static lookup cache, you cache all the lookup data at the starting of the session. in dynamic lookup cache, you go and query the database to get the lookup value for each record which needs the lookup. static lookup cache adds to the session run time....but it saves time as informatica does not need to connect to your databse every time it needs to lookup. depending on how many rows in your mapping needs a lookup, you can decide on this...also remember that static lookup eats up remember to select only those columns which are needed
With out using Updatestretagy and sessons options, how we can do the update our target table?
In session properties, There is an option



insert as update

update as update

like that

by using this we will easily solve
In realtime which one is better star schema or snowflake star schema

the surrogate will be linked to which columns in the dimension table.
In real time only star schema will implement because it will take less time and surrogate key will there in each and every dimension table in star schema and this surrogate key will assign as foreign key in fact table.
What is the mapping for unit testing in Informatica, are there any other testings in Informatica, and how we will do them as a etl developer.
how do the testing people will do testing are there any specific tools for testing
In informatica there is no method for unit testing. There are two methods to test the mapping.

1. But we have data sampling. set the ata sampling properties for session in workflow manager for specified number of rows and test the mapping.

2. Use the debugger and test the mapping for sample records.

No comments: