Oracle dba is not hard to learn. But need to have good 心理素质 to handle production database and trouble shooting. And it also need to be on-call. This job is for people who like to work for production operation, not for people who like to do research. Somehow I think project manager is much easy to do then DBA. I have to work on very short period of time for upgrade on production database on weekend a lot while PM just need to ask other people to do the job. May be I am wrong.