What is the main distinction between ETL and ELT processes?

The main distinction between ETL (Extract, Transform, Load) and ELT (Extract, Load, Transform) processes is that ETL transforms data before loading it into a database. In the ETL process, data is first extracted from its source, then transformed into a suitable format or structure necessary for analysis, and finally loaded into the target database or data warehouse. This sequence is designed to ensure that the data is clean, organized, and ready for use immediately once it is loaded.

In contrast, the ELT process extracts the data and loads it directly into the target system before any transformation takes place. The transformation happens afterward, typically within the target system such as a data warehouse, taking advantage of its processing power. This allows for greater flexibility and efficiency in handling large volumes of data, as the transformations can be performed using the more powerful capabilities of modern cloud-based platforms.

The option highlighting that ETL transforms data before loading captures this essential distinction, illustrating how ETL prepares the data to be ready for use right upon loading, rather than dealing with raw data as in ELT until after it has been stored.