RE: In what scenario ETL coding is preferred than Data...
Data scrubbing process is difficult. That is file contains date column like 20070823 but data warehouse requires date as 08/23/2007 in that case it is difficult.
RE: In what scenario ETL coding is preferred than Database level SQL,PL/SQL coding?
Usually Warehouse is preferred in banking insurance health care domains. In these environments especially in banks output is provided by business person in excel notepad word Access format. Suppose if the user wants to draw a survey or graph using all these information then we normally go for reports to generate these reports source data must be in sync (or single source) so we use warehouse to convert all these sources to single source system using ETL code.
RE: In what scenario ETL coding is preferred than Database level SQL,PL/SQL coding?
I assume ETL coding means using ETL tools like Informatica.
If the data is coming from completely different source systems as flat files cobol files RDBMS XML etc. it is better to use some intelligent ETL tools like informatica but if the data is from one or two simple sources like flat files and single RDBMS like Oracle there is no need to have expensive ETL tools this can be managed with SQL PL/SQL coding or database data loading tools like SQL Loader or SQL Server DTS.
