Informatica IDQ Interview Questions For Freshers

1. Can we export an object from the IDQ to Powercenter tool? if yes then how?
Answer:

  • Yes, we can export an object from the IDQ to Powercenter tool.
  • Connect to Repository Service
  • Locate your Project Folder in the Developer tool
  • Expand the Mapping tab
  • Choose your mapping(Needs to be exported)
  • Expand Informatica Folder
  • Click Object Export File
  • Locate under your project folder select the
  • Mapping/applets
  • Click Browse and select the location where you want to export it.

2. What does the update strategy actually mean and what are the different options available for it?
Answer:
Within Informatica, the data is processed based on row by row.
Within the target table, every row is inserted and it is marked as a default one.
The use of update strategy is done only when there is a need to update a single row or insert a row based on a sequence defined.
Within the update strategy, we need to mention the condition so that the specified row in the update strategy can be processed and the row can be actually marked as per the condition, i.e. updated or inserted.

3. What is a Connected Lookup?
Answer: The connected lookup is a lookup which participates in all the data flows and it is capable of receiving inputs directly from the pipeline itself.
Within connected lookup can be used within both dynamic cache and static cache.
Within connected lookup, it caches all lookup columns
The connected lookup will support user-defined values.

4. What is address doctor?
Answer: Address Doctor – The Address Validator transformation compares input address data with address reference data to determine the accuracy of input addresses and fix errors in those addresses. The transformation can create columns with new address data, corrected address data, and status information for each address. (E learning Portal)

5. What is the difference between a mapplet in PowerCenter and a mapplet in the Developer tool?
Answer: Mapplet in PowerCenter and in the Developer tool is a reusable object that contains a set of transformations. You can reuse the transformation logic in multiple mappings.
PowerCenter mapplet can contain source definitions or Input transformations as the mapplet input. It must contain Output transformations as the mapplet output.
Developer tool mapplet can contain data objects or Input transformations as the mapplet input. It can contain data objects or Output transformations as the mapplet output.
Mapping in the Developer tool also includes the following features:

  • You can validate a mapplet as a rule.
  • You use a rule in a profile.
  • A mapplet can contain other applets.

6. What is the difference between a source and target in PowerCenter and a physical data object in the Developer tool?
Answer: In PowerCenter, you create a source definition to include as a mapping source. You create a target definition to include as a mapping target. In the Developer tool, you create a physical data object that you can use as a mapping source or target.

7. What is a surrogate key?
Answer: A surrogate key is a replacement for the natural prime key. It is a unique identifier for each row in the table. It is very beneficial because the natural primary key can change which eventually makes update more difficult. They are always used in the form of a digit or integer.

8. What do you mean by filter transformation?
Answer: It is a medium of filtering rows in a mapping. Data needs to be transformed through filter transformation and then filter condition is applied. Filter transformation contains all ports of input/output, and the rows which meet the condition can only pass through that filter.

9. What is the benefit of partitioning a session?
Answer: Partitioning a session means solo implementation sequences within the session. Its main purpose is to improve the server’s operation and efficiency. Other transformations including extractions and other outputs of single partitions are carried out in parallel.

10. How are indexes created after completing the loan process?
Answer: For the purpose of creating indexes after the load process, command tasks at session level can be used. Index creating scripts can be brought in line with the session’s workflow or the post-session implementation sequence. Moreover, this type of index creation cannot be controlled after the load process at the transformation level.

11. Explain where we can find the throughput option in Informatica?
Answer: The throughput option is found in the Informatica workflow monitor.
Within the workflow monitor, right-click on the session, then click on the run properties.
Under source/target statistics we can find the throughput option.

12. What are the different tools in the workflow manager?
Answer:
Following are the different tools in workflow manager namely

  • Task Designer
  • Task Developer
  • Workflow Designer

13. How Union Transformation is used?
Answer:
It is a diverse input group transformation which can be used to combine data from different sources. It works like UNION All statement in SQL that is used to combine the result set of two SELECT statements.

14. What are the prerequisites tasks that are needed to achieve the session partition?
Answer: If you have to do the session partition then you need to start configuring the session to partition to source data and then you have to install Informatica server machine in different CPU. I.e. multifold CPU’s.

15. What is the difference between the PowerCenter Repository Service and the Model Repository Service?
Answer: The PowerCenter application services and PowerCenter application clients use the PowerCenter Repository Service. The PowerCenter repository has folder-based security. The other application services, such as the Data Integration Service, Analyst Service, Developer tool, and Analyst tool, use the Model Repository Service. The Model Repository Service has project-based security.
You can migrate some Model repository objects to the PowerCenter repository.

16. What is a predefined event?
Answer: As the name itself suggests that the event is predefined.
It is nothing but a file watch event. Within this process, it will wait for a certain file to arrive at a specific location.

17. What is the use of a target designer?
Answer:
Target Definition is created with the help of a target designer.

18. Briefly define reusable transformation?
Answer: Reusable transformation is used numerous times in mapping. It is different from other mappings which use the transformation since it is stored as metadata. The transformations will be nullified in the mappings whenever any change in the reusable transformation is made.

19. What does role-playing dimension mean?
Answer: The dimensions that are utilized for playing diversified roles while remaining in the same database domain are called role-playing dimensions

20. Define what is aggregate cache in aggregator transformation?
Answer: The aggregator is nothing but a function which stores all the data in the aggregator cache until and unless it deals with all the aggregate calculations.

So when you are executing a session in which you are using an aggregator transformation, the Informatica server will automatically start creating indexes and data caches in the memory to accommodate and process the transformation.

It is a known fact that Informatica server needs more space, it stores the overflow values in all the cache files.

21. What is the difference between a mapplet and a rule?
Answer: You can validate a mapplet as a rule. A rule is business logic that defines conditions applied to source data when you run a profile. You can validate a mapplet as a rule when the mapplet meets the following requirements:

It contains an Input and Output transformation.
The mapplet does not contain active transformations.
It does not specify cardinality between input groups.

22. Define what is a surrogate key?
Answer:
A surrogate key is nothing but a replacement of the primary key within the database.
It is considered to be a unique identification factor for each row within a table.
It is very helpful because the primary key can change and thus makes it difficult process to update the data, but not with the surrogate key.

23. What is the difference between the Power Center Integration Service and the Data Integration Service?
Answer: The Power Center Integration Service is an application service that runs sessions and workflows.
The Data Integration Service is an application service that performs data integration tasks for the Analyst tool, the Developer tool, and external clients. The Analyst tool and the Developer tool send data integration task requests to the Data Integration Service to preview or run data profiles, SQL data services, and mappings. Commands from the command line or an external client send data integration task requests to the Data Integration Service to run SQL data services or web services.

24. What is the Lookup transformation?
Answer: It is used for looking up data in a relational table through mapping. Lookup definition from any relational database is imported from a source which has the tendency of connecting client and server. One can use multiple lookup transformation in a mapping.

25. Explain the difference between mapping parameter and mapping variable?
Answer: When values change during the session’s execution it’s called a mapping variable. Upon completion, the Informatica server stores the end value of a variable and is reused when session restarts. Moreover, those values that do not change during the execution of the session are called mapping parameters. Mapping procedure explains mapping parameters and their usage. Values are allocated to these parameters before starting the session.

26. What is the difference between active transformations and a passive transformation in Informatica? Give example transformations for each?
Answer:
Active transformation:
It is a process it changes the number of rows that have gone through the mapping. This process is called as Active transformation

Some of the Active transformations are:

  • Sorter transformations
  • Filter transformations
  • Joiner transformations
  • Rank transformations
  • Router transformations, etc.

Passive transformation:

It is a process where it doesn’t change the number of rows that have gone through the mapping. This process is called Passive transformation.

Some of the Passive transformations are:

  • Expression transformation
  • Sequence Generator transformation
  • Lookup transformation
  • External procedure transformation
  • Output transformation
  • Input transformation, Etc.

27. Is it possible to use reference tables in Case Converter Transformation?
Answer:
Reference tables can be used only when the case conversion type is Title Case or Sentence case

28. At the time of Informatica PowerCenter installation, can you please let us know what all components are installed?
Answer:
The following components are installed while installing Informatica power center:

  • PowerCenter clients
  • Integration services
  • Repository service
  • PowerCenter Domain
  • Administration console for PowerCenter. company

29. Define what do you mean by workflow?
Answer:
Workflow can be defined as a set of instructions which are intended to communicate to the server and letting it know on how to implement the tasks.

30. Explain what are slowly changing dimensions? What are the different types of slowly changing dimensions that are available?
Answer:
Slow changing dimensions are those where the dimensions are meant to be changed in overtime. The slow changing dimensions are noted as SCD.

They are three different types of slowly changing dimensions, they are:

Slowly changing dimension-Type 1: In this type of SCD it has only current records
Slowly changing dimension-Type 2: In this type of SCD it has both current records and also historical records
Slowly changing dimension-Type 3: In this type of SCD it has current records plus one previous record

31. Describe Expression transformation?
Answer:
Values can be calculated in a single row before writing on the target in this form of transformation. It can be used to perform nonaggregate calculations. Conditional statements can also be tested before output results go to target tables.

32. What is complex mapping?
Answer:
Following are the features of complex mapping.
Difficult requirements
Many numbers of transformations
Complex business logic

33. What is the main use of stored procedure transformation?
Answer: The main use of stored procedure transformation is because it is a vital tool for maintaining and populating databases within the environment.

34. Explain what is meant by a transformation? What are the different types of transformations available in Informatica?
Answer: The term transformation itself depicts the nature of the activity. It is a repository object where it generates, modifies and passes the data.

The following are different types of transformations that are available in Informatica:

1. Aggregator transformation
2. Expression transformation
3. Filter transformation
4. Joiner transformation
5. Lookup transformation
6. Normalizer transformation
7. Rank transformation
8. Router transformation

35. What is the target load order?
Answer: Target load order is specified on the basis of source qualifiers in a mapping. If there are multifold source qualifiers linked to different targets then one can entitle order in which Informatica server loads data into targets. 

36. What is meant by pre and post-session shell command?
Answer:
Command task can be called as the pre or post-session shell command for a session task. One can run it as pre-session command r post-session success command or post-session failure command.

37. What are the prerequisite tasks to achieve the session partition?
Answer: In order to perform session partition one need to configure the session to partition source data and then installing the Informatica server machine in multifold CPU’s.

38. What is the scenario which compels the Informatica server to reject files?
Answer: This happens when it faces DD_Reject in update strategy transformation. Moreover, it disrupts the database constraint filed in the rows was condensed.

39. Explain to us whether two flat files can be joined together using Joiner Transformation? Explain what is joiner transformation means?
Answer: Yes, you can join two flat files together using joiner transformation.

Joiner transformation is an active and connected transformation where it is primarily used to join two sources of data. The source of data can be from one origin or it can be from two different origins.

40. Explain what is a parameter file and define what are the different values that are available in a parameter file?
Answer:
A parameter file is nothing but a file which is created in a text editor or a word pad.

The following different values can be defined in a parameter file, they are:
1. Mapping parameters
2. Mapping variables
3. Session parameters

41. Explain the code page compatibility?
Answer: When data moves from one code page to another provided that both code pages have the same character sets then data loss cannot occur. All the characteristics of the source page must be available on the target page. Moreover, if all the characters of the source page are not present in the target page then it would be a subset and data loss will definitely occur during transformation due to the fact the two code pages are not compatible. 

42. How can you validate all mappings in the repository simultaneously?
Answer: All the mappings cannot be validated simultaneously because each time only one mapping can be validated.

43. Explain sessions. Explain how batches are used to combine executions?
Answer: A teaching set that needs to be implemented to convert data from a source to a target is called a session. The session can be carried out using the session’s manager or pmcmd command. Batch execution can be used to combine sessions executions either in a serial manner or in a parallel. Batches can have different sessions carrying forward in a parallel or serial manner.

44. What do you mean by Enterprise Data Warehousing?
Answer: When the organization data is created at a single point of access it is called as enterprise data warehousing. Data can be provided with a global view to the server via a single source store. One can do periodic analysis on that same source. It gives better results but however the time required is high.

45. What do you mean Incremental Aggregation?
Answer: Option for incremental aggregation is enabled whenever a session is created for a mapping aggregate. Power center performs incremental aggregation through the mapping and historical cache data to perform new aggregation calculations incrementally.

46. What does the update strategy mean, and what are the different option of it?
Answer: Row by row processing is done by Informatica. Every row is inserted in the target table because it is marked as default. Update strategy is used whenever the row has to be updated or inserted based on some sequence. Moreover, the condition must be specified in update strategy for the processed row to be marked as updated or inserted.

47. Can you briefly define what is a reusable transformation?
Answer: The reusable transformation concept is widely used in mappings.
Reusable transformation is different from that of other mappings where they use transformations as it stores as metadata.
Whenever there is a change in the reusable transformation, the transformation will be nullified in the mappings.

48. What are different types of dimensions that are available in Informatica?
Answer:
They are three types of dimensions that are available:

  • Junk dimension
  • Degenerative dimension
  • Conformed dimension

49. What is an unconnected lookup?
Answer:
The unconnected lookup is entitled to receive input values from the result of LKP
With unconnected lookup, it can only return one column value
The unconnected lookup does not really support user-defined default values Conformed dimension

50. Where can we find the throughput option in Informatica?
Answer: Throughput option can be found in Informatica in workflow monitor. In workflow monitor, right-click on the session, then click on get run properties and under source/target statistics we can find throughput option.

51. What does the command task mean?
Answer: This specific task permits one or more than one shell commands in UNIX or DOS in windows to run during the workflow.

52. Where can we find the throughput option in Informatica?
Answer: Throughput option can be found in Informatica in workflow monitor. In workflow monitor, right-click on the session, then click on get run properties and under source/target statistics we can find throughput option.

53. What are the types of loadings that are available in Informatica?
Answer:
In Informatica, they are two types of loading:
1. Normal loading
2. Bulk loading
Normal loading is a process where the records are loaded one by one and it writes a log for the same. When compared to other types of loading normal loading the loading process takes time to the target source.

Bulk loading is a process where a set of records are loaded into the target database at once. When compared to the normal loading process, the bulk loading process takes very less time to load the data.

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