better get training for its architectureself-learning may miss-lead you to nowhere. You need a solid training to get the basics like database architecture. other areas can be self-learnt. Oracle has 5 fundamental parts: architecture, PL/SQL, performance tuning, backup&recovery, OEM/etc. But..., recent job market for Oracle DBA in Singapore is not good, I have 10+ years working experience, not find a job yet!!!