Sticking a knife in the back is unfortunately an integral part of Oracle’s corporate culture.
Understand, if you are doing good work, you may not be getting credit for it up the chain of command. I had two managers lie together to give a patent for my work to one of their girlfriends.
My best advice, if you are smarter than average, is to record everything that happens and be prepared to guess when you are being stabbed in the back, because no one will come and tell you or ask you anything about what happened, they will believe the lying scum that passes for management at Oracle.
Here you should always keep your eyes wide open and be a step ahead, but even the most experienced can have all the credit they deserved taken by someone else. I’m sure it hasn’t happened to you just once?