ETL Testing ETL Data Extraction Techniques 3

Question 1

When extracting from a flat-file source (CSV), which test validates that all columns were parsed correctly?

Accepted Answer

Column count and header validation

Answer

Primary key check

Answer

Referential integrity check

Answer

Index rebuild test

Question 2

Which extraction strategy is preferred when regulatory compliance requires zero impact on source system performance?

Accepted Answer

Offline extraction from a read replica or backup

Answer

Direct online extraction

Answer

Trigger-based extraction

Answer

Streaming CDC from primary

Question 3

In ETL testing, 'data completeness' during extraction specifically checks for:

Accepted Answer

All expected records and fields being present in the extracted dataset

Answer

Correct business rule application

Answer

Foreign key relationships in the target

Answer

Proper indexing in staging

Question 4

An ETL job extracts data from multiple source systems. Which test type ensures that records from all sources are correctly merged in staging?

Accepted Answer

Multi-source integration test

Answer

Transformation unit test

Answer

Target load test

Answer

Schema drift test

Question 5

What ETL test checks that special characters (e.g., accents, Unicode) in source data are preserved after extraction?

Accepted Answer

Character encoding validation

Answer

Row count reconciliation

Answer

Primary key uniqueness test

Answer

Null check

Question 6

Which SQL clause is MOST commonly used in timestamp-based incremental extraction to filter new records?

Accepted Answer

WHERE last_modified > :last_run_timestamp

Answer

GROUP BY last_modified

Answer

HAVING COUNT(*) > 0

Answer

ORDER BY created_date DESC