Thank you very much for your response.
I have already tried setting primary key field for the table. I didn't make a quick response, because i wanted to solve the issue by myself. Unfortunately, i couldn't make Grocery Crud work perfectly for Oracle 12c.
In my opinion, if Grocery Crud Enterprise works perfectly with all Oracle and MsSQL database versions, it would be a real revolution. Because big Companies generally prefer Oracle or MsSQL for database side and all companies really need quick solutions for CRUD operations and filtering-exporting-printing on web-side applications. Grocery Crud Enterprise is really easy to use for developers and can be understood easily for new developers, so that lots of time will be saved for a company.
The company I work for has 100 Million€ income per year. But in IT team, we couldn't figure out a solution faster than Grocery Crud Enterprise for now. Java, C# or solutions in other languages need much more coding than Grocery Crud Enterprise.
I have made a video for the steps i followed. You can see what i changed and what i have done for working some part of Grocery Crud Enterprise with Oracle 12c.
Sorry for the long video:
I am really waiting for a solution, like i thirst water in a desert.