Which statement correctly describes ETL compared to ELT?

• A. ELT transforms data before loading; ETL loads raw data and transforms inside the warehouse.
• B. ETL transforms data before loading into the warehouse; ELT loads raw data first and transforms inside the warehouse.
• C. ETL and ELT are identical.
• D. ELT is newer than ETL.

Answer: (B)

Where transformation happens relative to loading into the data warehouse is what sets ETL apart from ELT. In ETL, data is transformed before it is loaded—the extract and then the clean, structured, and ready-for-analysis transformation happens outside the warehouse, and only the transformed data is loaded in. In ELT, you load the raw data first and then perform the transformations inside the warehouse using its processing power. This distinction is precisely what the described statement captures: ETL transforms before loading; ELT loads raw data first and transforms inside the warehouse. This approach leverages modern warehouses’ ability to process large-scale transformations after data is stored, offering flexibility and potential efficiency for big data scenarios.