QELT: Query, Extract, Transform, Load

QETL (pronounced "kettle") refers to the set of practices, and also an approach.

• Approach: focuses on incremental loading, fetching and storing data on-demand, and dropping data when free space is needed. Transformations can be performed either on the source or the destination, and so the process can either be Q → T → E → L, or Q → E → L → T.
• Practices: The term QETL encompasses the set of practices includes ETL, ELT, and QETL.

This page focused on the approach.