ETL Testing MCQ 3

Question 1

What is the primary purpose of a 'staging area' in an ETL pipeline?

Accepted Answer

To temporarily hold raw extracted data before transformation

Answer

The staging area acts as a temporary buffer where raw source data lands so transformations can be applied without affecting source systems.

Question 2

During ETL testing, which check specifically validates that currency values are converted correctly between EUR and USD?

Accepted Answer

Data transformation accuracy check

Answer

Data transformation accuracy checks verify that business rules—including currency conversions, rounding, and exchange rate application—produce correct target values.

Question 3

A tester notices that dates stored as '08/14/2026' in the source appear as '2026-08-14' in the target. This is an example of:

Accepted Answer

Data format transformation

Answer

Converting date representations from MM/DD/YYYY to ISO 8601 format (YYYY-MM-DD) is a standard data format transformation applied during the ETL process.

Question 4

Which ETL testing scenario best tests the 'reject' or 'error' handling logic of a pipeline?

Accepted Answer

Injecting records that violate business rules or constraints

Answer

Injecting intentionally bad records—nulls in required fields, out-of-range values, foreign key violations—confirms the ETL correctly routes them to an error or reject table.

Question 5

What is 'delta extraction' in ETL?

Accepted Answer

Extracting only records that have changed since the last ETL run

Answer

Delta (incremental) extraction captures only new or modified records since the previous run, using timestamps, change data capture, or watermarks to minimize load.

ETL Testing - extract, transform, load Practice Test

ETL Testing - extract, transform, load Practice Test

ETL Testing MCQ 3