ETL Testing ETL Data Loading Strategies

Question 1

What is a 'full load' in ETL data loading?

Accepted Answer

Truncating the target table and reloading all records from scratch each run

Answer

Loading only changed records into the target

Answer

Loading records only to a staging area

Answer

Loading aggregated summary data only

Question 2

Which loading strategy appends only new or changed records to the target without removing existing data?

Accepted Answer

Incremental load

Answer

Full load

Answer

Bulk delete load

Answer

Schema-only load

Question 3

In ETL loading testing, which validation confirms that primary key uniqueness is maintained after loading?

Accepted Answer

Duplicate key / uniqueness constraint test

Answer

Referential integrity check

Answer

Row count reconciliation

Answer

Column data type test

Question 4

What is 'bulk loading' in ETL, and why is it preferred for large datasets?

Accepted Answer

Using database-native bulk utilities (e.g., SQL Server BCP, COPY in PostgreSQL) that bypass row-by-row processing for much faster throughput

Answer

Inserting records one row at a time via standard INSERT statements

Answer

Loading data in small batches of 10 records

Answer

Loading only the largest tables first

Question 5

Which test verifies that foreign key relationships in the target remain valid after an ETL load?

Accepted Answer

Referential integrity test

Answer

Data type test

Answer

Null check

Answer

Performance benchmark

Question 6

What is an 'upsert' operation in ETL loading?

Accepted Answer

Combining INSERT and UPDATE logic — insert if the record is new, update if it already exists

Answer

Inserting a new record and immediately deleting the old one

Answer

Uploading data to an external SFTP server

Answer

Upscaling a dimension table with new columns