Informatica Interview Questions and Answers Posted Under Data WareHousing Interview Questions, Informatica-Interview-Questions

Overview:Informatica Interview Questions Answers,Informatica Job Interview Questions and Solutions,Informatica Tool Interview Questions,Informatica Interview Questions with Answers

What are the types of loading in Informatica?Ans: There are two types of loading, normal loading and bulk loading. In normal loading, it loads record by record and writes log for that. It takes comparatively a longer time to load data to the target in normal loading. But in bulk loading, it loads number of records at a time to target database. It takes less time to load data to target.

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.

Define Informatica repository?Ans: 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.

What are the tasks that source qualifier performs?Ans: Join data originating from same source data base. Filter records when the informatica server reads source data. Specify an outer join rather than the default inner join specify sorted records. Select only distinct values from the source. Creating custom query to issue a special SELECT statement for the informatica server to read source data.

What is the target load order?Ans: Specify the target load order based on source qualifiers in a mapping. If you have the multiple source qualifiers connected to the multiple targets you can designate the order in which informatica server loads data into the targets.

How Union Transformation is used?Ans: The union transformation is a multiple input group transformation that can be used to merge data from various sources (or pipelines). This transformation works just like UNION ALL statement in SQL, that is used to combine result set of two SELECT statements.

Can two flat files be joined with Joiner Transformation?Ans: Yes, joiner transformation can be used to join data from two flat file sources.

What is a look up transformation?Ans: This transformation is used to lookup data in a flat file or a relational table, view or synonym. It compares lookup transformation ports (input ports) to the source column values based on the lookup condition. Later returned values can be passed to other transformations.

Can a lookup be done on Flat Files?Ans: Yes.

Which transformation should you need while using the cobol sources as source defintions?Ans: Normalizer transformaiton which is used to normalize the data.Since cobol sources are oftenly consists of Denormailzed data.

What is the difference between a connected look up and unconnected look up?Ans: Connected lookup takes input values directly from other transformations in the pipleline.Unconnected lookup doesnt take inputs directly from any other transformation, but it can be used in any transformation (like expression) and can be invoked as a function using :LKP expression. So, an unconnected lookup can be called multiple times in a mapping.

What are the types of data that passes between informatica server and stored procedure?Ans: 3 types of data Input/Out put parameters Return Values Status code.

What is the status code?Ans: Status code provides error handling for the informatica server during the session. The stored procedure issues a status code that notifies whether or not stored procedure completed sucessfully.This value can not seen by the user. It only used by the informatica server to determine whether to continue running the session or stop.

What is source qualifier transformation?Ans: When you add a relational or a flat file source definition to a mapping, you need to connect it to a source qualifier transformation. The source qualifier transformation represents the records that the informatica server reads when it runs a session. Which tool you use to create and manage sessions and batches and to monitor and stop the Informatica server?Ans: Informatica server manager.

Why we use partitioning the session in Informatica?Ans: Partitioning achieves the session performance by reducing the time period of reading the source and loading the data into target.

To achieve the session partition what are the necessary tasks you have to do?Ans:Configure the session to partition source data.Install the Informatica server on a machine with multiple CPUs.

What is the default join that source qualifier provides?Ans: Inner EquiJoin

What is Datadriven?Ans.The Informatica server follows instructions coded into update strategy transformations within the session mapping which determine how to flag records for insert, update, delete or reject. If we do not choose data driven option setting, the Informatica server ignores all update strategy transformations in the mapping.

What is pollingAns: It displays the updated information about the session in the monitor window. The monitor window displays the status of each session when you poll the Informatica server.

What are the types of mapping wizards that are provided in Informatica?Ans: The designer provide two mapping wizard.Getting Started Wizard creates mapping to load static facts and dimension tables as well as slowly growing dimension tables.Slowly Changing Dimensions Wizard, creates mappings to load slowly changing dimension tables based on the amount of historical dimension data we want to keep and the method we choose to handle historical dimension data.

Explain reference cursor? (PL/SQL)Ans: Cursor doesn't have a return type but A Reference Cursor have a return type and it as 2 type one is Strongly Typed Cursor and Weakly Typed Cursor

What is a source qualifier? What do you mean by Query Override?Ans: Source Qualifier represents the rows that the PowerCenter Server reads from a relational or flat file source when it runs a session. When the definition of the relational or flat file is added to mapping then it is connected to Source Qualifier transformation. The default query is SELECT statement containing all the source columns. Source Qualifier has capability to override this default query by changing the default settings of the transformation properties.

Can you generate reports in Informatica?Ans: Yes. By using Metadata reporter we can generate reports in Informatica.

What is metadata reporter?Ans: It is a web based application that enables you to run reports against repository metadata. With a Meta data reporter you can access information about your repository with out having knowledge of sql, transformation language or underlying tables in the repository.

Define mapping and sessions?Ans: Mapping: 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.What are the settiings that you use to cofigure the joiner transformation?Ans: Master and detail source Type of join Condition of the join.

What are the types of groups in Router transformation?Ans: 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.

How many ways you can update a relational source defintion and what are they?Ans: Two ways 1. Edit the definition 2. Reimport the defintion

What are the options in the target session of update strategy transsformatioin?Ans: Insert Delete Update Update as update Update as insert Update esle insert Truncate tableWhat is the default source option for update stratgey transformation?Ans: Data driven.

Which tool would you use to create and manage sessions and batches and to monitor and stop the Informatica server?Ans: Informatica server manager.

What are partition points?Ans: Partition points mark the thread boundaries in a source pipeline and dividethe pipeline into stages

How can you recognize whether or not the newly added rows in the source are get inserted in the target?Ans: In the Type2 mapping we have three options to recognize the newly added rows 1. Version number2. Flag value3. Effective date Range

What are two types of processes that Informatica runs the session?Ans: Load manager Process: Starts the session, creates the DTM process, and sends post-session email when the session completes. The DTM process. Creates threads to initialize the session, read, write, and transform data, and handle pre and post-session operations.

What is parameter file?Ans: Parameter file is to define the values for parameters and variables used in a session.A parameter file is a file created by text editor such as word pad or notepad.You can define the following values in parameter file:-Maping parametersMaping variablessession parameters.

Differences between Normalizer and Normalizer transformation.Ans: Normalizer: It is a transformation mainly using for Cobol sources,it's change the rows into columns and columns into rowsNormalization: To remove the redundancy and inconsistency

What is the default source option for update strategy transformation?Ans: Data driven.

What is Data driven?Ans: The Informatica server follows instructions coded into update strategy transformations with in the session mapping determine how to flag records for insert,update,,delete or reject .If you do not choose data driven option setting, the Informatica server ignores all update strategy transformations in the mappingWhat is difference between $ and $$ parameters/variablesAns: $ are System defined and $$ are User defined variables

How to use data from SAP/Oracle Apps /MainframeAns: Through power exchange.

What are the types of lookup?Ans: Connected and unconnected.

What is meant by lookup caches?Ans: The informatica server builds a cache in memory when it processes the first row of a data in a cached look up transformation. It allocates memory for the cache based on the amount you configure in the transformation or session properties. The informatica server stores condition values in the index cache and output values in the data cache.

How to find all invalid mappings in a folderAns: we can find the invalid mappings information from the rep_all_mappings view with a query Select mapping_name from rep_all_mappings Wheresubject_area='Folder_Name' And parent_mapping_is_valid 1

What are different kinds of aggregation?Ans: Some examples of aggregation are SUM, AVG, COUNT, MAX, MIN, LAST, MEDIAN, PERCENTILE etc.

What is difference between maplet and reusable transformation?Ans: Maplet: one or more transformationsReusable transformation: only one transformation

Define maping and sessions?Ans: 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.

What is a code page?Ans.A code page contains encoding to specify characters in a set of one or more languages and is selected based on source of the data. The set code page refers to a specific set of data that describes the characters the application recognizes. This influences the way that application stores, receives, and sends character data.

What is Target Update override?Ans: It overrides the default update statement in the target properties.

How are Informatica object files stored?Ans: They are stored as XML in the Informatica Repository.

How do we tune the performance of Informatica transformations?Ans: Use Filter transformation before transforming the unwanted data. Go for dynamic lookups as far as possible. Use Union transformations in place of using multiple transformations with binded SQLs.

In what conditions we cannot use Joiner transformation?Ans: Both pipelines begin with the same original data source. Both input pipelines originate from the same Source Qualifier transformation. Both input pipelines originate from the same Normalizer transformation. Both input pipelines originate from the same Joiner transformation. Any of the input pipelines contains an Update Strategy transformation. Any of the input pipelines contains a connected or unconnected Sequence Generator transformation.

If there is no PK or FK in the target table, how do we update or insert value into the table?Ans: We take a dynamic lookup on the target and do a comparison with source in an expression and flag it.

What are the settings that you use to configure the joiner transformation?Ans: Master and detail source Type of join. Condition of the join.

What are the join types in joiner transformation?Ans: 1. Normal (Default)2. Master outer3. Detail outer4. Full outerWhen to use Abort, Decode functions?Ans: Abort can be used to Abort / stop the session on an error condition. If the primary key column contains NULL, and you need to stop the session from continuing then you may use ABORT function in the default value for the port. It can be used with IIF and DECODE function to Abort the session.

What is constraint based loading ?Ans: Constraint based loading. the data was loaded into the target table based on the Constraints.i.e if we want to load the EMP&DEPT data, first it loads the data of DEPT then EMP because DEPT is PARENT table EMP is CHILD table. In simple terms, it loads PARENT table first then CHILD table.

In a joiner transformation, you should specify the source with fewer rows as the master source. Why?Ans: Joiner transformation compares each row of the master source against the detail source. The fewer unique rows in the master, the fewer iterations of the join comparison occur, which speeds the join process.

What is Incremental Aggregation?Ans: Whenever a session is created for a mapping Aggregate Transformation, the session option for Incremental Aggregation can be enabled. When PowerCenter performs incremental aggregation, it passes new source data through the mapping and uses historical cache data to perform new aggregation calculations incrementally.

What is the default join that source qualifier provides?Ans: Inner equi join.

What are the options in the target session of update strategy transformations?Ans:InsertDeleteUpdateUpdate as updateUpdate as insertUpdate else insertTruncate table

Which transformation should we use to normalize the COBOL and relational sources?Ans: Normalizer Transformation.

What is the use of tracing levels in transformation?Ans: Tracing levels store information about mapping and transformations.

What are the basic needs to join two sources in a source qualifier?Ans: Two sources should have primary and foreign key relationships. Two sources should have matching data types.

What is update strategy transformation?Ans: This transformation is used to maintain the history data or just most recent changes in to target table.

Describe two levels in which update strategy transformation sets?Ans: Within a session. When you configure a session, you can instruct the Informatica Server to either treat all records in the same way (for example, treat all records as inserts), or use instructions coded into the session mapping to flag records for different database operations. Within a mapping. Within a mapping, you use the Update Strategy transformation to flag records for insert, delete, update, or reject.

What are the various types of transformation?Ans: Various types of transformation are: Aggregator Transformation, Expression Transformation, Filter Transformation, Joiner Transformation, LookupTransformation, Normalizer Transformation, Rank Transformation, Router Transformation, Sequence Generator Transformation, Stored Procedure Transformation,Sorter Transformation, Update Strategy Transformation, XML Source Qualifier Transformation, Advanced External Procedure Transformation, External Transformation.

What is the difference between active transformation and passive transformation?Ans: An active transformation can change the number of rows that pass through it, but a passive transformation can not change the number of rows that pass through it.

What is the use of control break statements?Ans: They execute a set of codes within the loop and endloop

Informatica ETL Tool Interview Questions Posted Under Data WareHousing Interview Questions, Informatica-Interview-Questions

Overview:Informatica ETL Interview Questions asked in top companies like Cap Gemini,IB ,HP,Accenture,Dell,Cisco ,CTS.Learn by sharing Informatica Questions asked in various companies

What are tracing levels in transformation?

What is a Shortcut and what is the difference between a Shortcut and a Reusable Transformation?

What is DTM process?

What is Powermart and Power Center?

What is the difference between connected lookup and unconnected lookup?

What is the functionality of Lookup Transformation (connected & un connected)

What is Update Strategy?

why sorter transformation is an active transformation?

Can you access a repository created in previous version of Informatica?

How a LOOKUP is passive?

How do we estimate the depth of the session scheduling queue? Where do we set the number ofmaximum concurrent sessions that Informatica can run at a given time?

How does the server recognise the source and target databases?

How to get the records starting with particular letter like A in Informatica?

If source qualifier having employee details.the empid is in 5th placle and deptno is in 7th column then. you selected sort by 2. but how the Informatica server will come know that those are the fields to sort.

What are the type of loading procedures?

What are the connected or unconnected transformations?

What are the options in the target session of update strategy transsformatioin?

What are Transformations?

What is a source qualifier?

What is DTM process?2. What are the output files that Informatica creates during the session running?3. limitations of joiner transformations?under which conditions we can't use joiner transformation?

What is pre-session and post-session?

What is the difference between connected stored procedure and unconnected stored procedure?

What is the gap analysis?

What is use of event waiter?

Why we use lookup transformations?

Can you copy the batches?

How can I get distinct values while mapping in Informatica in insertion?

How do we estimate the number of partitons that a mapping really requires? Is it dependent onthe machine configuration?

How is the Sequence Generator transformation different from other transformations?

How to get two targets T1 containing distinct values and T2 containing duplicate values from one source S1.

If the workflow has 5 session and running sequentially and 3rd session has failed how can we run again from only 3rd to 5th session?

Under what circumstance can a target definition are edited from the mapping designer. Within the mapping where that target definition is being used?

What are the Data Cleansing Tools used in the DWH?What are the Data Profiling Tools used for DWh?

What are the out put files that the informatica server creates during the session running?

What are two modes of data movement in Informatica Server?