Started with an intent to modernize data integration, Talend has grown leaps and bounds to become the numero uno cloud and data integration software of choice today. A certification in Talend is considered to be a highly valuable skill, and companies these days are actively looking to hire Talend professionals.
So, this might just be the right time to prepare yourself and get ahead of the competition.
Here, we’ve selected and compiled the top Talend interview questions and answers that can help you ace a Talend interview and land your dream job.
Now, let’s look at these frequently asked Talend Interview Questions.
Top Talend Interview Questions & Answers
Question 1: What is Talend ?
Talend is an open-source ETL (Extract, Transform Load) tool used for data integration. It has different softwares to provide solutions for data management, data preparation, cloud storage, big data, data quality and enterprise application integration.
It allows companies to securely communicate with each other in real-time and take data-driven decisions for lasting sustainability.
Question 2: What are The Advantages of Using Talend Over Other ETL Tools?
- Talend is an open-source tool, which means it has the backing of a large developer community.
- Talend tasks are automated and maintained seamlessly which makes data integration faster.
- Talend offers a unified environment to organisations to meet their needs.
- Talend is a next generation software, which means it is created to fulfill your present-day as well as future requirements.
- Talend is a self-service platform offering native performance and high data quality.
Question 3: Describe a ‘Project’ in Talend?
A ‘Project’ is described as the top-most physical structure in Talend that is responsible for compiling and storing technical resources. Some of these resources include:
- Business Models
- Context Variables
Question 4: What is a Job Design?
A Job in Talend is a single Java class in technical terms and is defined as the fundamental executable unit of anything built on Talend. It uses graphical representation to define the functioning and extent of information available to Talend.
A business’s needs are translated into code, programs and routines to implement the flow of data.
Question 5: Describe a ‘Component’.
Any functional piece in Talend that can perform an operation is known as a ‘Component’. On the surface, components are graphical representations.
However, in technical terms, the snippets of Java codes that are generated on the execution of a Job are what we call components. They are compiled by Talend as and when a Job gets saved.
Question 6: What are The Different Types of Connections That are Present in Talend?
Connections in Talend represent data that will either be processed, or that which is the sequence of a job or data output.
There are four types of connections available in Talend. They are
Question 7: Explain The Various Types of Connections in Talend.
Row: This connection represents the data flow. Some row connections are Lookup, Multiple Input/Output and Uniques/Duplicates. Apart from these, Filter, Output, Rejects, ErrorRejects are also row connections.
Iterate: Using the iterate connection, you can perform a loop function on files in a file directory, rows or database entries.
Trigger: The dependency between Subjobs and Jobs triggered in the order as per the Trigger’s nature is created by Trigger.
Link: Using the Link connection, a user can transfer the information in a table schema to the ELT mapper in Talend
Question 8: What are The Types of Triggers in Talend?
There are two categories of Triggers:
1.Subjob Triggers which include OnSubjobOK, OnSubjobError and Run if. OnSubjobOk is executed once the previous Subjob has been executed.
2.Component Triggers which include OnComponentOK, OnComponentError and Run if. OnComponentOk is executed once the previous component has been executed.
Also Read: 7 Tools To Manage Big Data.
Question 9: Explain The Different Schemas Supported By Talend
The major schema types supported by Talend are:
- Repository Schema: The Repository schema is reusable by multiple Jobs. Changes made to the schema are automatically reflected across all Jobs.
- Generic Schema: The Generic Schema functions as a shared resource amongst different types of data sources. It isn’t tied to a single data source.
- Fixed Schema: These are read-only. They are predefined schemes that are some of Talend’s components.
Question 10: What are Routines? Explain its Types
Routines are those pieces of the Java code that can be reused. They allow you to write custom codes in Java which in turn contributes to optimised processing of data and improves Job capacity.
There are two types of routines in Talend:
- System routines: System routines are read-only. They can be called directly.
- User routines: These are custom routines created by users. They are either entirely new or adaptations of existing routines.
Question 11: Can Schema be Defined at Runtime?
No, it is not possible to define schemas during runtime. This is because schemas signify data movement and so, they should be defined when the components are configured.
Question 12: State The Differences Between ‘Repository’ and ‘Built-in’?
Following are the differences between Built-in and Repository:
- In Built-in, data is stored within a Job locally unlike Repository where the data is stored within the Repository centrally.
- Only a local Job can use the data in Built-in. In the case of Repository, any Job inside a Project can use it.
- Data within a Job is accessible to make updates in Built-in unlike Repository where the data is read-only.
Question 13: Define Context Variables
Context variables are parameters defined by users that a Job has access to during runtime. The values of these variables change as the Job goes from the Development stage to the stages of Test and Production.
There are three ways to define Context Variables:
- Embedded Context Variables
- Repository Context Variables
- External Context Variables
Question 14: What is The ‘Outline View’ Used For in Talend Open Studio?
The Outline View in TOS helps in keeping track of the return values contained in a component. User-defined values that are created in a tSetGlobal component are included in the Outline View.
Question 15: What is The tMap Component? What are the Various Functions That can be Performed Using the tMap Component?
tMap in Talend is a core component of the ‘Processing’ family. It allows you to map the input to the output data.
Its functions are:
- It allows you to add or remove columns
- Transformation rules can be applied on any type of field
- Input data and output data can be filtered using the constraints specified
- It allows you to reject data
- You can multiplex or demultiplex data using the tMap component
- It allows you to concatenate the data
- It allows you to interchange the data
Question 16: What is The ETL Process?
ETL is short for Extract, Transform and Load. It is used to indicate the process of retrieving data from the sources and moving it to a data warehouse, a Big Data system or a business intelligence platform.
Extract: This is the process of retrieving data from the different types of storage systems or databases. This could include a Relational database, an excel file, XML file, etc.
Transform: In this step, the data accessed from storage systems undergoes analysis and operations to transform data into a format suitable for a data warehousing system.
Load: This is where the transformed data is finally loaded to a repository or data warehouse through optimised usage of resources.
Question 17: What is The Difference Between “insert or update” and “update or insert”
The primary difference between the two is the sequence of actions:
insert or update: Here, Talend seeks to insert a record and updates it if it finds a matching primary key existing.
update or insert: Here, Talend first seeks to update a record and looks for the matching primary key. If it doesn’t find an existing matching key, it inserts the record.
Question 18: What are The Differences Between TOS for Data Integration and TOS for Big Data
TOS for Big Data provides support for various Big Data technologies while serving as a superset of TOS for DI. All the functionalities of TOS for Data Integration are available to TOS Big Data.
TOS for DI supports Java codes only. TOS for Big Data on the other hand, supports Java codes as well as MapReduce codes.
Question 19: Name The Big Data Technologies Supported By Talend ?
Some of the most used Big Data technologies supported by Talend are:
- Google Storage
Question 20: Which Language is Used for Pig Scripting in Pig ?
Question 21: Which is The Mandatory Service that Enables Coordination of Transactions Between Talend Studio and HBase?
The Zookeeper service
Question 22: What is The Use of tContextLoad?
tContextLoad is part of Talend’s ‘Misc’ components. Using tContextLoad, you can modify the values present in the active context. The context from a data flow is loaded using tContextLoad.
When parameters defined in the input haven’t been declared in the context, the tContextLoad sends a warning signal.
It also sends a warning if the context has not undergone initialization in the incoming data.
This brings us to the end of our article. We hope a quick brush-up of these questions and answers will help you crack your Interview.
Talend products are touted as the next-generation tools that hold tremendous promise in the IT market, being chosen worldwide by companies of all sizes. Therefore, this in-demand architecture is recommended for anyone who wants to master IT technologies. The above information will surely help you begin your learning journey!
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