Operational Source System
Its the traditional OLTP systems which stores transaction data of the organizations business. Its generally used one record at any time not necessarily stores history of the organizations information’s. Operational source systems generally not used for reporting like Data Warehouse Components.
Data Staging Area
Data staging area is the storage area as well as set of ETL process that extract data from source system. It is everything between source systems and Data warehouse.
Data staging are never be used for reporting purpose. Data is extracted from source system and stored, cleansed, transformed in staging area to load into data warehouse.
Staging are not necessarily the DBMS. It could be flat files also. Staging area can be structured like normalized source systems. It totally depends on choice and need of development process.
Data Presentation Area
Data presentation area is generally called as data warehouse. It’s the place where cleaned, transformed data is stored in a dimensionally structured warehouse and made available for analysis purpose
Data Access Tools
once data is available in presentation area it is accessed using data access tools like Business Objects.