ss domain. Using this more abstract approach means that more data sources of varying types can be incorporated with less effort, and such heterogeneous data sources might be very relevant in a future that can bring us the semantic web and perhaps other external sources. With regards to the processing of the ETL flow, which I have definitely done my share of on the physical level, I was impressed by the work of Vasiliki Tziovara, Panos Vassiliadis and Alkis Simitis titled "Deciding the Physical Implementation of ETL Workflows". This project proposes that we implement a declarative language for ETL in order to obtain detail independence and leave it to the system to implement the actual workflow, including the application of sorters. Again, from personal experiences, I have learned the hard way how important sorting and indexing can be during the implementation of a physical level ETL flow. This led me to suggest a "sort upon load" in the sense of applying a primary i...
Ekow J. Otoo, Doron Rotem, Sridhar Seshadri