Help. I am new to database administration

Hi!

I have been an developer on the oracle database for almost a year, but now I am starting looking at the administration part of the database. But it is a big area. So I have a few:

• What is the differences between sys/system/internal user and what is sysdba and sysoper.
• I have to export a database from one server to another server, when I do the import do I have to have a database created or will the import create the database. And how about the table spaces, who will create them. I couldn't find a step by step example in the manuals so any help on this question would be appreciated.
• Can you have more than one database on your server, if yes how is it done.

I hope that anyone can help me.

-- 
Casper Thrane
Systemdeveloper
Benau A/S