ETL Testing ETL Data Quality and Validation 1 — Questions and Answers
Question 1: Which ETL data quality dimension ensures that every required record and field is present in the target dataset?
- Accuracy
- Completeness (Correct answer)
- Consistency
- Timeliness
Correct answer: Completeness
Completeness measures whether all expected records and fields exist in the target, ensuring no data is missing during the ETL process.
Question 2: What type of ETL validation compares row counts between the source and target tables after a load?
- Schema validation
- Referential integrity check
- Reconciliation testing (Correct answer)
- Boundary testing
Correct answer: Reconciliation testing
Reconciliation testing compares aggregate metrics such as row counts and sum totals between source and target to detect data loss or duplication.
Question 3: In ETL testing, which check verifies that a foreign key in the target fact table references a valid primary key in the corresponding dimension table?
- Null check
- Referential integrity check (Correct answer)
- Data type validation
- Duplicate check
Correct answer: Referential integrity check
A referential integrity check ensures that foreign key values in fact tables correspond to existing primary keys in dimension tables, maintaining relational consistency.
Question 4: Which technique is used to validate that transformed date fields conform to a specific format such as YYYY-MM-DD?
- Referential integrity check
- Checksum validation
- Pattern or format validation (Correct answer)
- Range check
Correct answer: Pattern or format validation
Pattern or format validation uses regular expressions or format rules to confirm that field values match the required structure, such as date formats.
Question 5: A range check in ETL data quality testing is primarily used to verify which of the following?
- That numeric values fall within an acceptable minimum and maximum boundary (Correct answer)
- That all primary keys are unique
- That source and target column counts match
- That NULL values are properly handled
Correct answer: That numeric values fall within an acceptable minimum and maximum boundary
A range check validates that numeric or date values lie within a predefined acceptable range, catching outliers or corrupted data.
Question 6: Which ETL validation approach computes an MD5 or SHA hash on source data and compares it to the same hash computed on target data?
- Boundary testing
- Checksum validation (Correct answer)
- Null constraint testing
- Metadata validation
Correct answer: Checksum validation
Checksum validation hashes source and target data and compares the results to detect any unintended alterations or corruption during transformation.
Question 7: During ETL testing, which dimension of data quality is violated when the same customer has two different birth dates recorded in separate source systems?
- Completeness
- Timeliness
- Consistency (Correct answer)
- Uniqueness
Correct answer: Consistency
Consistency is violated when the same entity has conflicting attribute values across different sources or tables, indicating a lack of data harmonization.
ETL Testing ETL Data Quality and Validation 1
Which ETL data quality dimension ensures that every required record and field is present in the target dataset?