Seeking database certification advice

I'm looking for some good advice on planning my next certification, which
will be for a database facility at the associates level.
I'm feeling that my SCJP 1.4 ambitions are getting pretty close... My study
regime started with a complete and slow read of "The Java Programming Lang.,
Third Edition." by Arnold, Gosling and Holmes. The next phase of study
consisted of exploring my own questions about features of the language with
the JDK on Linux. My current phase of study is a read of the Bates book
and working the Chapter problems.. I'm getting an average of 85% in the K&B
book but my first questions in Java Rules Roundup nets me about 75% ;
"Hood Ornament" as they say... I'm within passing range and I think by the end of this week, I will be ready to take the exam. Shooting for next Monday.
Here's my (weird) situation. I have 5 years of IT experience without a
degree. In those five years, I executed and delivered two Java consulting
engagements. One involving XML4J and Beans for a rules engine, the other
involving JSP and Java CORBA client access to C++ servers that I wrote myself for a product prototype. Prior professional experience included
extensive coding and devel with C++, DCE/RPC, Oracle 7, PL/SQL. I recently
(May 2003) completed my long lost degrees in Chemistry and Physics (of all things). My certification endeavors are (1) a personal review and return to my prior level of professional achievement and (2) an authentication of my prior demonstrated abilities. These are strange times. People dont believe
your hard work or enthusiasm.
Once I get my SCJP 1.4, I want to a database certification, mainly as a
review, and to prove that I have "the right stuff". Alot of people dont
believe my resume, and I hope that certification will help dispel alot of
the bullshit. Following a basic database certification, I'd really like to
do the SCJD and take my time with it...
So here are my questions:
(1) What is cheaper to do? Oracle Associate or DB/2 Associate ?
(2) What is consider "harder" ? I've heard some dark gossip that the OCA
is considered "easy" and that the exams lack credibility because they are
non-proctored.
(3) Do people "really" still consider DB/2 and Oracle to be different
products? I know the stored procedures are totally different, but SQL/92
(or... SQL/99) is just that.
(4) What offers better professional credibility?
(5) Can I get versions of DB/2 Enterprise Edition that will last more than
90 days for self-training purposes? Same question but for 9i as well.
(6) How tough are the DB certifications relative to SCJP ? I think SCJP
is a ball-buster because it honestly requires understanding how to avoid
making mistakes that bite you at run-time, and, most importantly, how to
successfully use the features of the language to write reliable and maintainable code. Virtuous and nobles goals. I'm glad that the SCJP is
not easy, but I'd hate if my SQL goals are this tough.

Last but not least, If I cant find a decent job with decent people having
completed two newly minted BS degrees and two Certifications, I'll gladly take my rightful place as a day-labourer doing construction work.

-- Jim

1)DB2 is cheaper
2)Level of difficulty is the same
3)Depend what you are going to do. C++ API server programming is definitively different, but JDBC programming is quite similar.
4)Credibility is the same but Oracle has considerably more market share on Unix and NT
5) DB2 PE (personal edition) has no time bomb, but it has some features disabled.
6)Studying RDBMS is like reading Answering Machine manual, no intellectual challenge just learning various features.