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Talend Interview Questions

Talend is a popular open-source data integration and management software. As a result, acquiring Talend skills can open up numerous opportunities in various industries. This article aims to provide aspiring candidates with useful details about the commonly-asked Talend interview questions as well as tips on how to answer them to make the preparation process much more productive.

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If you're looking for Talend Scenario Based Questions, you are in the right place. Here Mindmajix presents a list of Top interview questions on Talend. There are a lot of opportunities from many reputed companies in the world. According to payscale, the Average Salary for Talend Employees is $88k. So, You still have the opportunity to move ahead in your career by choosing Talend.

Frequently Asked Talend Interview Questions
  1. What is Talend?
  2. What is Talend Open Studio?
  3. What are the components in Talend Open Studio?
  4. What are the ways to define Context variables?
  5. What are the programming languages that support Talend?
  6. Define a project in Talend
  7. What are the ways to improve the performance of a Job in Talend?
  8. List the functions of tMap?
  9. What’s new in v5.6?
  10. What is the difference between ETL and ELT?

Talend Interview Questions and Answers 

We have Segregated these Talend Interview Questions into two Categories:

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Basic Interview Questions on Talend

1. What is Talend?

Talend is an open-source data integration platform that provides solutions for data integration and data management. It offers various integration software and services for data management, data quality, data integration, Big data, data preparation, cloud storage, and enterprise application. It is designed to combine, convert, and update data in various business applications.

Explore Talend Tutorial for more information

2. What is the full name of Talend?

Talend Open Studio

3. What is Talend Open Studio?

Talend Open Studio is an open-source ETL tool used for data integration and Big data. It is based on the eclipse developer and design tool. Talend Open Studio acts as a code generator that provides data transformation scripts and underlying programs in Java.

4. What are the components in Talend Open Studio?

A component is a functional unit that is used to perform a single operation in Talend. With the help of drag and drop functions, we can use the components to perform operations. The component can be a snippet of Java code that is generated as a part of a job.

5. When did Talend Open Studio come into existence/launch?

Launched in October 2006

6. Talend Open Studio is written in which computer language?


Related Article: Java for Talend

7. What are the programming languages that support Talend?

The programming languages that are supported by Talend are as follows:

  • Java SE
  • XQuery, SQL, XPath
  • Scripting languages: Javascript, Ruby, PHP, ECMAScript, and Groovy

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8. What is the most current version of Talend Open Studio?

The latest version of Talend Open Studio is v. 7.3.1  

Talend Open Studio available for :

  • Data Integration
  • Big Data
  • Daya Quality
  • ESB

9. Why Talend is called a code generator in Talend?

Talend is a code generator because it offers GUI, that allows the user to perform drag and drop the component to create a job. Talend translates these jobs into Javascript.

10. Define routines?

Routines are reusable pieces of code that can be used to optimize data processing by the use of custom code. It also helps to improve the job capacity and the features of Talend studio. The routines are of two types:

  • System routine: The system routine is the read-only code that can call inside any job.
  • User routine: The custom-created routine by the users either by making a new one or the existing one.

11. Define a project in Talend?

In Talend Studio, the highest physical structure used for storing several kinds of data integration jobs, routines, metadata, etc., is known as Project.

12. Define tMap?

tMap is an advanced component that integrates itself as a plugin to Talend Studio. It is used for mapping the data and also transforms and routes data from single or multiple sources to single or multiple destinations.

Related Article: tmap in Talend

13. List the functions of tMap?

The functions of tMap are as follows:

  • Apply transformation rules on any type of field
  • Multiplex and demultiplex of data
  • Filter input and output data using constraints
  • Add or remove columns
  • Reject data
  • Concatenate and interchange the data

14. How to access global and context variables?

To access the global and context variables, use the shortcut key Ctrl+spacebar.

Related Article: Context Variables in Talend

15. Define Context variable in Talend?

Context variables are the user-defined parameters used by Talend that are defined as a job at runtime. These variables may change their values as a job from development to test and production environment.

16. What are the ways to define Context variables?

There are three ways to define Context variables. They are as follows:

  • Embedded Context variables
  • External Context variables
  • Repository Context variables

17. Explain Subjob?

A subjob can be defined as a component or no. of components that are joined by the data flow. Each individual component can be considered as a Subjob when they are not connected to each other. A job can have one or more sub jobs. 

18. How to schedule a job in Talend?

It is required to export the job as a standalone program to schedule a job. Then using the Operating System scheduling tools such as Cron, Windows Scheduler, Linux, etc. we can schedule the jobs.

19. What is the difference between XMX and XMS parameters?

XMX parameter is used to specify the maximum heap size in java, whereas the XMS parameter is used to determine the initial heap size in java.

20. What is the function of the tXMLMap component?

tXMLMap is a component used for routing and transforming XML data flows mainly, when processing numerous XML data sources, with or without flat data is to be joined. 

21. What is the function of tJavaFlex?

tJavaFlex allows the user to add personalized code to integrate into the Talend program. With the use of the tJavaFlex function, we can enter three java code parts such as start, main, and end that constitute a kind of component to the desired operation. 

22. What is the function of tJava?

tJava allows the user to enter personalized code to integrate into the Talend program. This code can be executed only once. It makes it possible to extend the functionalities of a Talend job using custom Java commands. 

23. What is the use of tContextLoad?

tContextLoad is used to load a context from a flow. This component performs two controls. It alerts when the parameters are defined in the incoming flow are not defined in Context, and another control is it also alerts when a context value is not initialized in the incoming flow. 

24. What are the components used to close a hive connection automatically?

To close a Hive connection automatically, we can use tPostJob and tHiveClose components.

25. What is the language used for Pig scripting?

Pig is a platform using a scripting language to express data flows. It programs the operation to transform data using Pig Latin, which is the language used for pig scripting.

26. What are the various features that are available in the main window of Talend Open Studio?

The features that are available in the main window of Talend Open Studio are as follows:

  • Menubar
  • Toolbar
  • Workspace
  • Palette
  • Tab panel
  • Configure tabs
  • Repository
  • Outline view and code view

27. Explain the Palette panel in Talend Studio?

In Talend Studio, Palette is used to find the components required to create or design a job.

28. What is the use of Palette settings in Talend?

In the Palette settings view, we can set the preferences for the component searching from the palette and from the component list that appears on the design workspace when adding a component without using the palette.

29. What is the use of String handling routines in Talend?

The string handling routines allows the user to carry out different types of operations and tests on the alphanumeric expressions, depending on the Java methods.

30. What are the ways to improve the performance of a Job in Talend?

The following are the ways to improve the performance of a job in Talend:

  • Use of Talend ELT components when it is required
  • Remove unnecessary records using tFilterRows component
  • Use of Select Query to retrieve data from the DB
  • Split Talend Job into smaller SubJobs
  • Remove unnecessary fields or columns using tFilterColumns component
  • Use of Database bulk components

Advanced Talend Interview Questions

31. What is the use of Outline view in Talend Open Studio?

The Outline view provides an easy way to check out where the design workspace is located. It allows the user to check the return values available in a component.

32. Mention the configurations that are required to connect HDFS?

The following are the configurations that are required to connect HDFS:

  • NameNode URI
  • User name
  • Distribution

33. Mention the service that is required for coordinating the transactions between HBase and Talend studio?

Zookeeper client port service is required for coordinating the transactions between HBase and Talend Open Studio.

34. What is the use of tLoqate AddressRow component in Talend?

This component is used for correct mailing addresses associated with customer data to ensure a single customer view and better delivery for their customer mailings.

35. Can you edit generated code directly?

This is not possible; you cannot directly edit the code generated for a Talend Job.

36. If you want to include your own Java code in a Job, use one of these methods?

  • Use a tJava, tJavaRow, or tJavaFlex component.
  • Create a routine by right-clicking Routines under Code in the Repository and then clicking Create a routine

37. Is it possible to use Binary or ASCII mode transfer in SFTP connection?

No, it is not possible to use Binary or ASCII transfer mode in an SFTP connection. Because SFTP does not support any kind of transfer modes as it is an extension to SSH.

38. Which component is used to sort data?

tSortRow, tExternalSortRow

39. What is the default pattern of a Date column in Talend?

By default, the date pattern for a column of type Date in a schema is “dd-MM-yyyy”.

40. Built-In vs. Repository, Which is better?

It depends on the way you use the information is used. Use Built-In for information that you only use once or very rarely. Use the Repository for information that you want to use repeatedly in multiple components or Jobs, such as a database connection.

41. What is the difference between OnSubjobOK and OnComponentOK?

It belongs to Subjob TriggersIt belongs to Component Triggers
It is used to trigger the next subjob on the condition where the subjob is completed without any errors. It is used to trigger the target component after the execution of the source component completes without any errors.
This link can be used only with the first component of the subjob.This link can be used with any component in a job.

42. How can you normalize delimited data in Talend Open Studio?

By using the tNormalize component

43. What is tMap?

tMap is an advanced component, which integrates itself as a plugin to Talend Studio tMap transforms and routes data from single or multiple sources to single or multiple destinations. It allows you to define the tMap routing and transformation properties.

44. What types of joins are supported by the tMap component?

  • Inner
  • Outer
  • Unique
  • First
  • Joins

45. What is the function of tDenormalizeSortedRow?

tDenormalizeSortedRow combines in a group of all input sorted rows. The distinct values of the denormalized sorted rows are joined with item separators. It synthesized sorted input flow to save memory.

46. Which Talend component is used for data transform using built-in .NET classes?

tDotNETRow helps you facilitate data transform by utilizing custom or built-in .NET classes.

47. What is tJoin?

tJoin joins two tables by doing an exact match on several columns. It compares columns from the main flow with reference columns from the lookup flow and outputs the main flow data and/or the rejected data.

48. What do you understand by MDM in Talend?

Master data management, through which an organization builds and manages a single, consistent, accurate view of key enterprise data, has demonstrated substantial business value including improvements to operational efficiency, marketing effectiveness, strategic planning, and regulatory compliance. To date, however, MDM has been the privilege of a relatively small number of large, resource-rich organizations. Thwarted by the prohibitive costs of proprietary MDM software and the great difficulty of building and maintaining an in-house MDM solution, most organizations have had to forego MDM despite its clear value.

49. What’s new in v5.6?

This technical note highlights the important new features and capabilities of version 5.6 of Talend’s comprehensive suite of Platform, Enterprise, and Open Studio solutions.

50. With version 5.6, Talend?

  • Extends its big data leadership position enabling firms to move beyond batch processing and into real-time big data by providing technical previews for the Apache Spark, Apache Spark Streaming and Apache Storm frameworks.
  • Enhances its support for the Internet of Things (IoT) by introducing support for key IoT protocols (MQTT, AMQP) to gather and collect information from machines, sensors, or other devices.
  • Improves Big Data performance: MapReduce executes on average 24% faster in v5.6 than in v5.5, and 53% faster than in v5.4.2, while Big Data profiling performance is typically 20 times faster in v5.6 compared to v5.5.
  • Enables faster updates to MDM data models and provides deeper control of data lineage, more visibility, and control.
  • Offers further enterprise application connectivity and support by continuing to add to its extensive list of over 800 connectors and components with enhanced support for enterprise applications such as SAP BAPI and Tables, Oracle 12 GoldenGate CDC, Microsoft HDInsight, Marketo, and Salesforce.com.

Talend FAQs

51. What is the difference between Talend and Pentaho

Comparison    Talend    Pentaho Kettle
ApproachCode generationMeta driven
MonitoringEnough tools to monitor logsEnough tools to monitor logs
RiskEqually complex like PentahoEqually complex like Talend
Data Quality (DQ)Graphical User Interface (GUI) featured by Data QualityGUI featured by DQ along with additional options
InterfaceModerate interfaceModerate interface
SpeedModerate performanceBest when compared to Talend
Community SupportStrong community supportStrong community support
DeploymentWorks on any java/Perl compatible machineRuns on Java compatible machines.

52. What are the schemas that are supported by Talend?

The schemas that are supported by Talend are as follows:

  • Repository schema: The repository schema can often be used across multiple jobs. If any changes are made in the schema, the entire job will effect automatically.
  • Fixed schema: The fixed schema is a read-only schema. For some components, the fixed schema is in-built in Talend.
  • Generic schema: The Generic schema is used as a sharable resource for multiple data sources. It is used where you want to limit the use of schema tied to a specific file type or database type.

53. Explain various connections that are available in Talend?

Connection defines whether the data has to be processed, data output, or the sequence of a job. The various kinds of connections that are available in Talend are as follows:

1. Row: The row connection handles the actual data. According to the nature of the flow process, it can be in the following types of row connections:

  • Main
  • Multiple Input/Output
  • Filter
  • Lookup
  • ErrorRejects
  • Rejects
  • Output
  • Uniques/Duplicates

2. Iterate: The iterate connection is used to execute a loop of files contained in the directory, on the database entries, or the rows contained in a file.

3.Trigger: Trigger connections are used to define the processing sequence, so there is no data handled through these connections. The trigger connections are of two types:

  • Subjob Trigger: On Subjob Ok, On Subjob Error, Run if
  • Component Trigger: On Component Ok, On Component Error, Run if

4. Link: The Link connection can be used with ELT components only. These links are used to transfer the table schema information to the ELT component to be used in specific Database query statements.

54. Is it possible to perform a Talend job partly?

Yes, it is possible to perform a Talend job partly using the command line. It is required to export the job along with its dependencies. After that, you can access its instruction files from the terminal. 

55. Explain Job design in Talend?

Job design is a design with at least one component connected together that allows the user to develop and run the dataflow management processes. It interprets the business requirements into routines, programs, and code to implement the data flow.

56. How to pass data from a parent job to a child job?

Create a Standard job called Childjob. Open the context to define two variables, such as name and scope. These variables are used to pass a value from the parent job to a child job.

57. Is it possible to exclude headers and footers from the input files before loading the data?

Yes, it is possible to exclude headers and footers easily before loading the data from the input files.

58. Explain the use of an Expression editor in Talend?

In Talend Open Studio, all expressions such as Input, Var, Output, and constraint statements can be viewed and edited with the use of the Expression editor. It provides visual comfort to write any function in a dedicated view. 

59. What is the difference between Built-In and Repository?

All the information is stored centrally in the repository.All the information is stored locally on the job. It allows the user to enter and edit all the information.
It enables the user to import read-only information into the Job from the repository.It allows the user to enter all the information manually.
It can be used overall by any Job in the project.It can be used by the Job only.

60. Explain the error handling in Talend?

There are few ways in which the error can be handled in Talend are as follows:

  • Use of dedicated components provided by Talend
  • Use of links between two components in a job
  • Use of custom to design an appropriate job

61. How can we run multiple jobs in parallel within Talend?

In Talend, various jobs and Subjobs in multiple threads can be executed to reduce the runtime of a job. There are three ways for parallel execution in Talend are as follows:

  • Multithreading
  • tParallelize component
  • Automatic parallelization
Related Article: Tricks and Tips of Talend

62. What is the difference between “Insert or Update” and “Update or Insert”? 

  • Insert or Update: First tries to insert a record, but if a record with a matching primary key already exists, instead of updating that record.
  • Update or Insert: First tries to update a record with a matching primary key, but if none already exists, instead inserts the record.

From a results point of view, there are no differences between the two, nor are there significant performance differences. In general, choose the action that matches what you expect to be more common: Insert or Update if you think there are more inserts than updates, Update or Insert if you think there are more updates than inserts.

63. Is it possible to define a variable that can be accessed from multiple jobs?

Yes, you can declare a static variable in a routine, and add the setter/getter methods for this variable in the routine. The variable is then accessible from different Jobs.

64. How to change the background color of the job designer in Talend?

By selecting the preferences of the window menu, then by clicking on the color menu, we can change the background color of the job designer.

65. Mention the configurations that are required to connect HDFS?

The following are the configurations that are required to connect HDFS:

  • NameNode URI
  • User name
  • Distribution
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66. Explain the function of tPigLoad component?

tPigLoad sets up a connection to the data source for a current transaction. It helps to load original input data to an output stream in a single transaction once the data has been validated. 

67 Is it possible to define schema at runtime in Talend?

No, it is not possible to define a schema at runtime. The schema defines the movement of data, so it should be defined while configuring the components or at some point of the layout.

68. Differentiate between tMap and tJoin.

To create a join between different data sources, you can use either tJoin or tMap. However, tJoin is a basic component that is just used to unite two data sources, whereas tMap contains additional properties that are tailored to specific purposes.

The following table lists the differences between tJoin and tMap:

There is a main output flow and a reject output flow. There are multiple output flows.
An exact match between the expression's keysWhile providing the joining condition, expression in the columns is used.
Support for the single-match modelMultiple match models are supported (Unique match, First match, and All matches)
Support for a single look-up processSupport for a variety of look-up flows and the ability to load numerous Parallel lookups are carried out.
 On-disk storage of look-up data 
 Each primary record's look-up data is reloaded.
 Supports the option to 'die on error'.

69. What is the difference between the ETL and ELT?

Extract, Transform, and Load (ETL)Extract, Load, and Transform (ELT)
The ETL process is that it extracts the data, transforms the data, and then it loads the data into the database.The ELT process is that it extracts the data, loads it into the database, and then it transforms the data.
It is easy to implementIt requires good knowledge of tools to implement
It supports relational dataIt supports the unstructured data
It does not provide Data lake supportIt allows the use of Data lake support with unstructured data.
With the increase in the size of data, the processing slows down, and it requires to wait until the transformation completesThe processing does not depend on the size of the data.
It is used to transfer data from the source database to the destination data warehouse.It is a data manipulation process, which is used in data warehousing.


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Keerthana Jonnalagadda working as a Content Writer at Mindmajix Technologies Inc. She writes on emerging IT technology-related topics and likes to share good quality content through her writings. You can reach her through LinkedIn.

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