SQL & PL/SQL

Hi,

could someone please explain the difference between so called "cursor oriented processing" and so called "set-based processing"?

I am little confused with articles available on Internet and various opinions with regard to that matter, for example: that oracle is cursor-based engine which itself does not support the row result set mechanism and depends on passing reference cursors as input/output parameters to the client, that reference cursors parameters do not exist in any database system other than Oracle, and that all other databases send row result sets back to the client.

I don't understand this at all. I know that all flagship database products support: (1) explicit cursors (declaring, opening, fetching, closing, deallocating), and (2) result sets returned by interactive queries.

So, what they are referring to with the slang noted above? What is the difference when I issue a query in sqlplus and get the result on the screen as opposed to the same query issued on mysql or isql (sybase) getting the same result on the screen?