Hi, I am a complete beginner in Oracle 12 and I'm trying to install it for school. I have installed Oracle12c in Windows 7 and created a user. But when I start SQL Developer, I can't see the point "Tables" or "Tabellen"(German), like it is shown in many tutorials. Am I using the wrong user(SYSTEM)? I also tried SQL Plus, but it doesn't seem to recognize any SQL command I enter. I also tried SYSTEM as SYSDBA in SQL Plus, but nothing works. The goal would be to create and fill a table. What is missing?