It is somewhat related to another question I posted earlier, namely the view had no single field which could be used as a unique identifier.Net Beans required I select an ID field, so I just chose one part of what should have been a multi-part key.
External tables are essentially stored SQL*Loader control files, but because they are defined as tables, we can access our flat-file data using all available read-only SQL and PL/SQL operations.
We can also read flat-files in parallel and join files to other files or tables, views and so on.
And it depends on all layers of a web application environment: The back-end storage, the web server and the web application itself (and possibly other layers or applications).
The Gartner Group, however, estimates that 75% of attacks are at the web application layer, and found out "that out of 300 audited sites, 97% are vulnerable to attack".
In general there is no such thing as plug-n-play security.