Ask about ETL and E-LT

 Hi all,

   I have been read about E-LT in DataWarehouse. It said that: 

------------------------------------------

Isolating the load process from the transformation process removes an inherent dependency between these stages. In addition to including the data necessary for the transformations, the extract and load process can include elements of data that may be required in the future. Indeed, the load process could take the entire source and load it into the warehouse. 

------------------------------------------

   I think that in ETL, these two processes (load and tranformation) also separate ! With ETL, are there some things that  dependency  beetween these stages ?

   I were tried search on MOS to look for some article about ETL and E-LT but no results. Anyone give me some link on MOS ?