How does it work?

As far as I know I feel like I am keeping up pretty well with all of the class issues so far. However, the whole semester I have felt just a little confused about some of the "behind the scenes" kind of things. Particularly I am a little confused about Oracle. Prior to starting my work with Oracle I imagined it as a very userfriendly interface much like Access. It is quite different than expected. So, what I am confused with now is how Oracle actually works. How does it actually run?