Your DBA sets the max # of connections to the database; if you go beyond that limit, you won't be able to connect. That simple. Oracle deals with all other concurrency problems for you, mostly (it won't allow two processes to muck with the table at the exact same time); for the heavy-duty stuff you'll need to understand transactions though (COMMIT and ROLLBACK).

and I am *not* going to reproduce any Oracle documentation here. I'm sorry, I know it's a mess finding out anything you need to know about Oracle looking through what they give you. C'est dommage, though =(

Philosophy can be made out of anything. Or less -- Jerry A. Fodor