ETL Testing Trivia 5

Question 1

What is 'end-to-end ETL testing' and when is it most valuable?

Accepted Answer

Testing the full pipeline from source extraction through transformation to target load to validate the complete data flow

Answer

End-to-end ETL testing validates the entire data flow from source system through all transformations to the final target, catching integration defects that unit tests of individual phases would miss.

Question 2

Which ETL concept describes replacing an entire target table with freshly extracted and transformed source data on each run?

Accepted Answer

Full load (truncate and reload)

Answer

A full load — also called truncate-and-reload — deletes all existing target data before each run and reloads everything from the source, ensuring the target always mirrors the source completely.

Question 3

When testing ETL, what does 'referential integrity' checking confirm?

Accepted Answer

That foreign key values in the target fact table correctly match existing keys in the related dimension tables

Answer

Referential integrity testing verifies that every foreign key in the fact or child table corresponds to a valid primary key in the related dimension or parent table, ensuring no orphaned records exist.

Question 4

In ETL performance testing, what is a common metric used to measure throughput?

Accepted Answer

Rows processed per second (or per minute) through the pipeline

Answer

ETL throughput is commonly measured in rows per second or rows per minute, indicating how quickly the pipeline can process data volume during the extraction, transformation, and load phases.

Question 5

What is the role of an ETL 'audit table' or 'control table' in a data pipeline?

Accepted Answer

Recording job run metadata such as start time, end time, record counts, and status for each ETL execution

Answer

An audit or control table logs execution metadata for each ETL run — including timestamps, record counts loaded, and pass/fail status — enabling monitoring, reconciliation, and troubleshooting.

ETL Testing - extract, transform, load Practice Test

ETL Testing - extract, transform, load Practice Test

ETL Testing Trivia 5