You Can't Afford To Skip These Top 15 ETL Exam Interview Questions

Introduction

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This article is going to help you with the best ETL testing interview questions, and answers you just can't miss.

For the top businesses, ETL is taken as an important component in managing the business data and the information perfectly. ETL means Extract, Transform, and Load. All these three components are defined with different objectives and purposes.

• Extract means fetching or reading data from a particular database,
• Transform means converting data to a compatible format to report and analyze well, and
• Load means writing or loading final data to the targeted database.

ETL testing interview questions and answers

ETL testing is a popular trend today with plenty of job opportunities and attractive salary options. Here, we have given a complete list of ETL testing interview questions and answers for freshers and experienced to help the job seekers in the best way. We have taken full care to give precise answers to each of the questions. Let us discuss ETL Testing Interview Questions and Answers one by one in the next sections.

A. ETL testing interview questions and answers for Freshers

1). What is ETL and Explain the Three Basic Seps Necessary for the Data Integration Process?

ETL means Extract, Transform, and Load. All these three components are defined with different objectives and purposes.

• Extract means fetching or reading data from a particular database,
• Transform means converting data to a compatible format to report and analyze well, and
• Load means writing or loading final data to the targeted database.

2). How can you Compare ETL Testing and Manual Testing?

ETL is the automated testing process where you don’t need any technical knowledge other than the software. Also, ETL testing is extremely fast, systematic, and assures top results as needed by businesses.

Manual testing is highly time-consuming where you need technical knowledge to write the test cases and the scripts. It is slow, needs effort, and is highly prone to errors.

3). Explain the Major ETL Testing Operations in Detail?

ETL tools verify whether data is fetched correctly or not. It verifies whether data is converted or loaded correctly at a perfect time frame as needed by the business requirements to enhance the overall scalability and performance.

It verifies whether data is loaded into the targeted database correctly or not without any truncation or data loss. Also, it reports invalid data and replaces the same with default values.

4). Define the Major Steps Included in the ETL Testing Process?

5). Define Facts in ETL Testing and Different Types of Facts?

Facts are the dimensions that are used to analyze data on different parameters. The three popular facts in ETL testing include- 

6). Do you have any Ideas about Cubes and OLAP Cubes?

Cubes – These are the data processing units that allow multi-dimensional analysis and each of the units is composed of fact tables and dimensions.

OLAP Cubes –These cubes store voluminous data in the multi-dimensional format that consists of facts and is categorized as dimensions.

7). Name a few Popular ETL Bugs?

Source Bugs, Calculation Bugs, ECP-related bugs, load condition bugs, and User-Interface bugs.

8). What are the Dimensions?

Dimensions are named as groups or categories to sort the summarized data.

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B. ETL Interview Questions and Answers for Experienced

9). How will you Define the Staging Place in ETL Testing?

The Staging place is the temporary storage area that is used during the Data Integration process. Here, Data is analyzed carefully for redundancy and duplication.

10). Define the ETL Mapping Sheet and its Significance?

The ETL mapping sheet contains all necessary information from the source file and stores the details in rows and columns. This mapping sheet helps experts in writing SQL queries to speed up the testing process.

11). What are the Tracing Levels in ETL Testing and its Types?

Tracing levels define the volume of data stored in the log files. They are divided into two major categories, these are Normal and Verbose. The normal category defines the tracing level in detail while the verbose category defines the tracing level at each row.

12). What is Fact Granularity?

The level at which information of Fact is stored is named as Grain of Fact or Fact Granularity.

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13). Explain what is Transformation in ETL Testing?

Transformation is defined as the repository objects to generate, modify or pass the data. There may be Active Transformation and Passive Transformation. It may be beneficial in different ways:

• It helps in getting values from tables quickly.
• It can update slowly changing dimension tables.
• It checks or verifies whether a record exists or not inside the table.

14). What is the usage of dynamic cache and static cache in transformations?

The dynamic cache is used to update the master table or dimension table that changes slowly. In the case of flat files, the static cache is used.

15). What are the Schema Objects and how are they Helpful in ETL Testing?

The schema objects are the logical structure to define the database data including tables, views, clusters, indexes, database links or function packages, etc.

This blog has guided you with the ETL Testing questions and answers that will help you to crack your interview easily. So, if you want to enroll yourself for ETL testing or quality testing, then do visit us at janbasktraining.com

16). What are the major ETL Testing Operations?

• ETL tools verify whether data is fetched correctly or not.
• It verifies whether data is converted correctly as needed by the business requirements.
• It verifies whether data is loaded into the targeted database correctly or not without any truncation or data loss.
• It makes sure that data is loaded at the perfect time frame to enhance the overall scalability and performance.
• Also, it reports invalid data and replaces the same with default values.

Conclusion

In summary, ETL tools have the potential to perform flawlessly with massive amounts of historical data and are required for ETL Testing. Experts usually employ the major ETL Testing operations due to the high demand for ETL testing. As a result, there are numerous career opportunities in the worldwide IT marketplace.

Only if you have a thorough understanding of technical aspects, ETL tools, and apps will you have a good chance of being hired swiftly. For this, you need to enroll in JanBask Training's software testing curriculum to have a better understanding of various testing techniques.

Do comment your thoughts and don’t forget to share your experiences. We wish you luck in your next interview!