From Oracle FAQ
Oracle Discoverer FAQ:
What is Oracle Discoverer and what is it used for?
Oracle Discoverer provides end users easy access to data and allow them to do data analysis and set-up ad-hoc queries.
Oracle Discoverer (like Oracle Reports and Express Objects) is part of Oracle's Business Intelligence set of tools.
Can one access non-Oracle databases via Discoverer?
Oracle Discoverer provides native connectivity to the Oracle Database Server and Oracle Rdb via Net8.
Connection to other databases are supported via ODBC.
What are the components of Oracle Discoverer?
- (Web) Viewer Edition: The Viewer Edition is used to view pre-defined reports. Viewer Edition is currently available for the Web only.
- User Edition: The User Edition is used by end users to perform ad hoc-query, reporting, analysis and web publishing.
- Plus Edition: The Plus Edition is similar to User Edition, except this is being accessed over web.
- Administration Edition: The Administration Edition is used to create and maintain the "End User Layer" (EUL) which is a metadata layer that hides the complexity of the database from end users.