1. As programmers, you should know the fundmental details of the database, especially when concurrency and performance is concerned.
2.Don’t stick to "database portability."
a. You are not going to need it.
b. It’s basically impossible since databases are so different from each other, concurrency strategy for example.
3.Don’t hesitate to make use Oralce’s features. Try to embrace more logic into DB. (I don’t agree with that)