For the top businesses, ETL is taken as the important component managing the business data and the information perfectly. ETL means Extract, Transform, and Load. All these three components are defined with different objective and purpose.
In brief, ETL tools had the capability to work with large historical data perfectly and they are necessary to carry out the ETL testing. With the huge demand for ETL testing, the major ETL testing operations are used by the experts frequently. So, there are plenty of job options are also available in the global IT marketplace.
If you have complete knowledge of technical features, ETL tools, and the apps, only then you have the chances of getting hired quickly. For this purpose, you should join the software testing program at JanBask Training to get a deeper understanding of various testing concepts.
In this blog, we will discuss on top 15 ETL testing interview questions and answers that are usually asked during the interviews. The questions and answers are prepared carefully by the JanBaskTraining experts giving training on Software testing tools. With the help of these questions, you would be able to give your best shot during the interview and it will also increase your overall chances of getting hired among other candidates.
Do comment your thoughts and don’t forget to share your experiences. We wish you luck in your next interview!
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 for each of the questions. Let us discuss ETL testing interview questions and answers one by one into next sections.
ETL means Extract, Transform, and Load. All these three components are defined with different objective and purpose.
ETL is the automated testing process where you don’t need any technical knowledge other than the software. Also, ETL testing is extremely faster, systematic and assure top results as needed by the businesses. Manual testing is highly time-consuming where you need technical knowledge to write the test cases and the scripts. It is slow, needs efforts, and highly prone to errors.
ETL tools verify either data is fetched correctly or not. It verifies either data is converted or loaded correctly at perfect time frame as needed by the business requirements to enhance the overall scalability and performance.
It verifies either data is loaded into the targeted database correctly or not without any truncate or data loss. Also, it reports about the invalid data and replaces the same with default values.
Facts are the dimensions that are used to analyse data on different parameters. The three popular facts in ETL testing include-
Cubes – These are the data processing units that allow multi-dimensional analysis and each of the unit is comprised of fact tables and the dimensions.
OLAP Cubes –These cubes store voluminous data in the multi-dimensional format that consist of facts and categorized as dimensions.
Source bugs, Calculation bugs, ECP related bugs, load condition bugs and the User-Interface bugs.
Dimensions are named as groups or categories to sort the summarized data.
The Staging place is the temporary storage area that is used during Data Integration process. Here, Data is analysed carefully for redundancy and duplication.
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.
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 verbose category defines tracing level at each row.
The level at which information of Fact is stored is named as Grain of Fact or Fact Granularity.
Transformation is defined as the repository objects to generate, modify or pass the data. There may be Active Transformation and the Passive Transformation. It may be beneficial in different ways:
Dynamic cache is used to update the master table or dimension table that changes slowly. In case of flat files, the static cache is used.
The schema objects are the logical structure to define the database data including tables, views, clusters, indexes, database links or function packages etc.
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