ETL Testing ETL Data Quality and Validation 3

Question 1

Which ETL data quality practice involves sampling a subset of records from the target and manually tracing them back to the source to confirm accurate transformation?

Accepted Answer

Data lineage tracing

Answer

Data lineage tracing follows individual records from source through each transformation step to the target, confirming that all business rules were applied correctly.

Question 2

When an ETL process truncates a string field from 100 characters in the source to 50 characters in the target, which data quality dimension is primarily at risk?

Accepted Answer

Accuracy

Answer

Accuracy is compromised when data values are altered incorrectly—such as truncation—resulting in target values that no longer faithfully represent the source.

Question 3

In ETL testing, which type of test validates that records rejected during a load are written to an error or reject table with appropriate error codes?

Accepted Answer

Error handling and reject log validation

Answer

Error handling validation confirms that records failing quality rules are correctly routed to a reject table with meaningful error codes rather than silently dropped.

Question 4

Which ETL validation technique compares aggregated totals (such as SUM of sales amounts) between source and target to confirm no data was lost during loading?

Accepted Answer

Aggregate balance testing

Answer

Aggregate balance testing sums key numeric columns in both source and target and compares the totals to detect any data loss, duplication, or rounding errors.

Question 5

A data profiling step performed before ETL development primarily helps teams to do which of the following?

Accepted Answer

Understand source data structure, quality issues, and anomalies prior to designing transformations

Answer

Data profiling analyzes source data to reveal structure, distributions, NULLs, duplicates, and anomalies, enabling accurate ETL design before development begins.

ETL Testing - extract, transform, load Practice Test

ETL Testing - extract, transform, load Practice Test

ETL Testing ETL Data Quality and Validation 3