Informatica interview questions (Part 3)

We will continue with third set of questions

Q 1 What is the use of Shared Folder?
Ans : Shared folders allow users to create shortcuts to objects in the folder.If you have an object that you want to use in several mappings or across multiple folders, we can place the object in a shared folder.we can then access the object from other folders by creating a shortcut to the object. Shortcuts inherit changes to their shared object. Shared folders in global repositories can be used by any folder in the domainOnce you make a folder shared, you cannot reverse it.

Q2 What are the different ways to migrate from one environment to another in Informatica
Ans
1.We can export repository and import into the new environment
2. We can use informatica deployment groups
3. We can Copy folders/objects
4. We can Export each mapping to xml and import in new environment

Q3 What is difference between mapping parameter and variable
Ans A Mapping parameter is a static value that you define before running the session and it value remains till the end of the session.when we run the session PowerCenter evaluates the value from the parameter and retains the same value throughout the session. When the session run again it reads from the file for its value.

A Mapping variable is dynamic or changes anytime during the session. PowerCenter reads the intial value of the variable before the start of the session and changes its value by using variable functions and before ending the session its saves the current value (last value held by the variable). Next time when the session runs the variable value is the last saved value in the previous session.

Q4 What is DTM
Ans DTM (Data Transformation Manager) is the process associated with the session taskThe Load Manager creates one DTM process for each session in the workflow. The DTM process performs the following tasks:
1.Reads session information from the repository.
2.Expands the server, session, and mapping variables and parameters.
3.Creates the session log file. Validates source and target code pages.
4.Verifies connection object permissions.
5.Runs pre-session shell commands, stored procedures and SQL.
6.Creates and runs mapping, reader, writer, and transformation threads to extract, transform, and load data.
7. Runs post-session stored procedures, SQL, and shell commands. Sends post-session email.

Q5 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

Q6 What are different type of repositories that can be created using Informatica Repository Manager?
Ans
1. Standalone Repository : A repository which functions individually and is unrelated to any other repositories.
2. Global Repository : This is a centralized repository in a domain. This repository can contain shared objects across the repositories in a domain. The objects are shared through global shortcuts.
3. Local Repository : Local repository is within a domain . Local repository can connect to a global repository using global shortcuts and can use objects in it’s shared folders.

Q 7 How to find all invalid mappings in a folder
Ans Use following query
SELECT MAPPING_NAME FROM REP_ALL_MAPPINGS WHERE SUBJECT_AREA='YOUR_FOLDER_NAME' AND PARENT_MAPPING_IS_VALIED <>1

Q 8 What are the data movement modes 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.

Q9 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.

Q10 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.

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