1. A computer-implemented method, comprising: receiving an abstract extract, transform, and load (ETL) operator model that specifies a plurality of operations for extracting, transforming, and loading data stored in one or more source systems into storage by a target system; receiving a first instance of an abstract ETL operator model, wherein the first instance of the abstract ETL operator model represents a first ETL job for loading data exhaustively from the one or more source systems to the target system; and generating, from the first instance, a second instance of the extended ETL operator model, wherein the second instance of the extended ETL operator model represents a second ETL job, wherein the second ETL job, when executed on a computer processor, performs an incremental extract, transform, and load of data retrieved from the source systems for storage by the target system.