What is ETL testing? ETL testing is a process of verifying the accuracy and completeness of data transfer from various sources to a target database, data warehouse or data mart through a series of operations like Extraction, Transformation, and Loading. What are the different types of ETL testing? The different types of ETL testing are: Data completeness testing Data accuracy testing Data transformation testing Data quality testing Performance testing Integration testing What is data completeness testing? Data completeness testing is a process of ensuring that all the expected data is being extracted from the source system, and it is loaded to the target system without any loss. What is data accuracy testing? Data accuracy testing is a process of verifying that the data that is being loaded into the target system is accurate and consistent with the source system. What is data transformation testing? Data transformation testing is a process of verifying that the data is transformed and converted as per the business rules and requirements. It includes testing of data type conversion, data aggregation, data cleaning, and data validation. What is data quality testing? Data quality testing is a process of verifying that the data is free from any anomalies like duplicates, missing values, or inconsistencies. What is performance testing? Performance testing is a process of verifying that the ETL process is efficient, and it is completing the data transfer within the defined time frame. What is integration testing? Integration testing is a process of verifying that the ETL process is integrated with other systems like source systems, data warehouse, or data marts, and it is working seamlessly. What are the common challenges in ETL testing? The common challenges in ETL testing are: Handling large volumes of data Managing complex data mappings Dealing with multiple data sources and targets Ensuring data accuracy and completeness Handling data quality issues Ensuring performance and scalability Maintaining data lineage and metadata What are the tools used in ETL testing? The commonly used tools in ETL testing are: Informatica PowerCenter Talend IBM InfoSphere DataStage Microsoft SQL Server Integration Services (SSIS) Oracle Data Integrator (ODI) What is data mapping? Data mapping is a process of defining the relationship between the source data elements and target data elements. What is a mapping document? A mapping document is a document that defines the mapping between the source and target data elements. It includes the source table, target table, and the mapping logic between them. What is a data lineage? Data lineage is a process of tracking the movement of data from the source system to the target system. It helps in understanding the data flow and identifying any issues or anomalies in the data. What is metadata? Metadata is data about data. It includes information about the structure, format, and context of the data.

1. Top 20 ETL Testing Interview Questions & Answers in 2023
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What is ETL testing?
ETL testing is a process of verifying the accuracy and completeness of data transfer from
various sources to a target database, data warehouse or data mart through a series of
operations like Extraction, Transformation, and Loading.
What are the different types of ETL testing?
The different types of ETL testing are:
Data completeness testing
Data accuracy testing
Data transformation testing
Data quality testing
Performance testing
Integration testing
What is data completeness testing?
Data completeness testing is a process of ensuring that all the expected data is being
extracted from the source system, and it is loaded to the target system without any loss.
What is data accuracy testing?
Data accuracy testing is a process of verifying that the data that is being loaded into the
target system is accurate and consistent with the source system.

3. www.magnitia.com |+91 6309 16 16 16 |+91 6309 17 17 17 | info@magnitia.com
What is data transformation testing?
Data transformation testing is a process of verifying that the data is transformed and
converted as per the business rules and requirements. It includes testing of data type
conversion, data aggregation, data cleaning, and data validation.
What is data quality testing?
Data quality testing is a process of verifying that the data is free from any anomalies
like duplicates, missing values, or inconsistencies.
What is performance testing?
Performance testing is a process of verifying that the ETL process is efficient, and it is
completing the data transfer within the defined time frame.
What is integration testing?
Integration testing is a process of verifying that the ETL process is integrated with
other systems like source systems, data warehouse, or data marts, and it is working
seamlessly.

4. www.magnitia.com |+91 6309 16 16 16 |+91 6309 17 17 17 | info@magnitia.com
What are the common challenges in ETL testing?
The common challenges in ETL testing are:
Handling large volumes of data
Managing complex data mappings
Dealing with multiple data sources and targets
Ensuring data accuracy and completeness
Handling data quality issues
Ensuring performance and scalability
Maintaining data lineage and metadata
What are the tools used in ETL testing?
The commonly used tools in ETL testing are:
Informatica PowerCenter
Talend
IBM InfoSphere DataStage
Microsoft SQL Server Integration Services (SSIS)
Oracle Data Integrator (ODI)
What is data mapping?
Data mapping is a process of defining the relationship between the source data elements
and target data elements.

5. www.magnitia.com |+91 6309 16 16 16 |+91 6309 17 17 17 | info@magnitia.com
What is a mapping document?
A mapping document is a document that defines the mapping between the source and
target data elements. It includes the source table, target table, and the mapping logic
between them.
What is a data lineage?
Data lineage is a process of tracking the movement of data from the source system to
the target system. It helps in understanding the data flow and identifying any issues or
anomalies in the data.
What is metadata?
Metadata is data about data. It includes information about the structure, format, and
context of the data.
15. What is data profiling?
Data profiling is a process of analyzing the data to understand its quality, completeness,
and accuracy.

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16. What is a test plan?
A test plan is a document that outlines the objectives, scope, approach, and timelines
for the testing process.
17. What is a test case?
A test case is a document that outlines the steps to be executed to test a specific
functionality or feature of the system.
18. What is regression testing?
Regression testing is a process of retesting the system to ensure that the new changes
or enhancements have not impacted the existing functionality.
19. What is user acceptance testing?
User acceptance testing is a process of testing the system by the end-users to ensure
that the system meets their requirements and expectations.

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20. What are the benefits of ETL Testing?
ETL testing provides several benefits, including:
Ensuring Data Accuracy: ETL testing verifies the accuracy and consistency of data after
extraction, transformation, and loading. This ensures that the data is reliable and consistent
with the business rules.
Improving Data Quality: ETL testing identifies and addresses data quality issues like
duplicates, missing values, or inconsistencies, improving the overall quality of data.
Enhancing Data Governance: ETL testing helps in maintaining data lineage and metadata,
enabling better data governance and compliance.
Enhancing Performance: ETL testing helps in identifying performance bottlenecks and
tuning the ETL process to optimize data transfer and processing.
Facilitating Integration: ETL testing ensures that the ETL process is integrated with other
systems like source systems, data warehouse, or data marts, and it is working seamlessly.
Reducing Risk: ETL testing reduces the risk of data loss or corruption during the data
transfer process.
Streamlining Data Management: ETL testing helps in automating the data transfer and
processing, reducing the manual effort and time required for managing data.
Overall, ETL testing is a critical process that ensures the accuracy, consistency, and
reliability of data in the data warehouse or data mart, enabling better decision-making and
business outcomes.