As far as I know, because I'm not that familiar with oracle either, Oracle doesn't have an Identity functionality as SQL Server has. That's why they use sequence.
Looking for information to confirm this, I found that they included something similar in Oracle until 12c, so before that, sequence was the way to go.
Luis C.How to post data/code on a forum to get the best help: Option 1 / Option 2
Are you seriously taking the advice and code from someone from the internet without testing it? Do you at least understand it? Or can it easily kill your server?