Hi, Both are different. Oracle developer means, using SQL and PL/SQL coding you should need to build forms,reports, and applications as per business standard requirement of your company. In short we can say, it needs programming skills. In Oracle Application DBA, you should need to maintain database for Oracle developer,application developer,java developer. In short we can say that, as Oracle Application Database Administrator (DBA) you need to maintain databases and don't need programming skills.
Sql is mandatory For both two courses. I think pl/sql is difficult when compare with DBA at the same time DBA work is very difficult.