Oracle Database Discussions

Hello.

I have to develop a program in C# that manages details about the students, taxes, courses, etc and prints some reports.
It's for my license degree.

The programming part is not that hard but the task that is killing me is designing the database because I have poor experience with data modeling.
I don't have access to my university's database so I need to make one myself..and the teachers won't help..

I tried to make a diagram but I realised that I cannot do it, I got stuck.
An university database can get extremely complex and it's hard to make .. so I wonder if any of you know where can I find a sample ERD for a University. I need one as complete as possible.

Any help is appreciated..