ETL Testing 面试题与答案
问题 6. What is incremental loading in ETL?
Incremental loading is a technique where only the new or changed data since the last ETL run is extracted, transformed, and loaded into the target system, reducing processing time and resource usage.
Example:
Instead of reloading the entire dataset, only records that have been added or modified since the last load are processed in incremental loading.
问题 7. What are the common challenges in ETL testing?
Common challenges in ETL testing include data completeness, data accuracy, performance testing, handling large volumes of data, and managing metadata.
Example:
Ensuring that all records are loaded, validating transformation rules, and optimizing performance for large datasets are challenges in ETL testing.
问题 8. What is data reconciliation in ETL testing?
Data reconciliation involves comparing the data in the source system with the data in the target system to ensure that they match, identifying and resolving any discrepancies.
Example:
Comparing the total number of records in the source and target systems is a simple form of data reconciliation in ETL testing.
问题 9. What is surrogate key in ETL?
A surrogate key is a unique identifier assigned to a record in the target system to maintain consistency and integrity during the ETL process.
Example:
In a data warehouse, a surrogate key may be assigned to each record to simplify data management and improve performance during ETL operations.
问题 10. Explain the concept of data lineage in ETL.
Data lineage is the tracking and visualization of the flow of data from its source through various transformations to its final destination in the target system.
Example:
Creating a data lineage diagram helps understand the path and transformations applied to data from its origin to its use in the data warehouse.
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