Can an IBM DB2 DBA learn Oracle? Follow one DB2 DBA as she prepares to take the Oracle Certified Associate Examination.
As a consultant, I am always in learning mode. Usually, I'm learning a new
release of DB2 or how to prevent a new security exploit. Recently, I decided to
focus my energy on Oracle. I've always known a "little" about Oracle,
but now, I wanted to learn more.
I know many DBAs don't see value in certifications, and I understand the
argument. Even though I agree that product experience is the better teacher,
prepping for a certification helps me ensure that I learn enough about the
product to avoid 'testing jitters'. Based on personal experience, I know that
studying for an exam means that I over-prepare and learn more than I would have
if a test had not been looming. When I was first learning DB2 (more than a few
years ago), I found that preparing for a certification exam forced me to find
quality study time because I don't like to flunk tests.
I thought that the Oracle Certified Associate designation, which requires
passing two tests, would be a realistic goal since it is the first level of
certification offered for Oracle Database Administrators. I did get one break.
A few years ago, I did some Oracle to DB2 conversions. As part of that work I
learned enough about Oracle to take and pass exam 1Z0-007, "Introduction
to Oracle9i SQL". After checking the Oracle certification requirements, I
found that having passed this exam would count as credit for the first of the
two required tests necessary to attain the OCA certification.
With only one test to go (1Z0-052, Oracle Database 11g: Administration I), I
thought I could probably just take a class and sit for the second exam. As I
quickly learned when I attended an Oracle University class, that assumption
turned out to be a delusion. The Oracle Database 11g: Administration Workshop 1
(http://education.oracle.com ) convinced me that I would need a lot more
preparation than I originally thought.
What I eventually discovered was that I probably would have a more difficult
time passing the exam than most new Oracle DBAs. Why? My DB2 knowledge would
actually hinder me. When I started this journey, I didn't realize I'd almost
have to "unlearn" what I know about DB2 in order to clear my mind
before tackling the necessary concepts to pass the OCA exam.
I had originally decided that my approach to this effort would be to treat
this exercise as I might if I needed to learn a new language. I would build on
the knowledge I already had about DB2 databases and then just translate that to
"Oracle". I found some big stumbling blocks early in that effort. For
example, the terms "instance" and "database" are near and
dear to my DB2 LUW database heart, but they conjure different mental visions
when discussing these terms with Oracle DBAs. Obviously, memory structures
would be different as well, which would mean tuning would be different, which
would mean…well, you get the picture.
While the fundamentals between DB2 and Oracle seem to correlate well (after
all a database by any other name must have certain fundamental functionality in
order to achieve market prominence), the terms used to describe that
functionality do not need to be identical. Database functionality is important,
the ability to consistently produce correct results is important, but the
actual names for the descriptive terms are trivial until you need to learn what
those terms represent. So, there I sat, with some strong mental images of DB2
terms and the concepts they represent to a DB2 DBA, and realizing that those
terms did not necessarily represent similar concepts from the Oracle
To DB2 DBAs an Instance is not "the Database". I think of the
instance as the outer circle of resources and control, with the database(s)
living inside the circle. Sure, I can have more than one instance on a machine
and I can choose whether each instance has only one database or several. The
instance is created first, started (db2start) and any associated databases can
then be created. Once a db2start finishes its task, any databases that have
already been created in that instance are ready for connections.
The Oracle world takes a slightly different approach with these terms and I
did not have a good DB2-to-Oracle translation tool to use, so I struggled to
make sense of the Oracle meanings. The Oracle instance is started, yes, but
there are several options. That's when then the DB2 to Oracle knowledge
translation really got fuzzy for me. The Oracle instance is
"associated" with a specific database and the database has to be
mounted and opened before users can access it. The Oracle instance uses locks
to manage internal consistency. In DB2, locks are managed in the database.
Processes connect and disconnect from the Oracle instance, but with DB2,
connections are made to the database. Well, I thought, this is not going to
interpret well into my DB2-centric mindset.
Of course, there are terms and concepts that are similar between the two.
Crash recovery, for example, proceeds through a comparable course of events for
both platforms. The important concepts were there, but the approaches and those
darn terms were different enough to challenge me. So, after realizing this was
not going to be easy, I began my search for more information.
While I am still looking for that DB2 to Oracle Rosetta stone, the good news
is that I found some terrific resources for learning the material. That made my
If you are preparing for an Oracle certification, valuable information can
be gained for free on the following sites:
Take a trip to Tahiti, or rather Oracle's version of Tahiti.
A list of the exam topics that are tested on the exam covered are located
at Oracle Certification Program
Oracle Learning Paths can be found at Oracle Database 11g: Database Administrator (New) - Learning Paths
Exam testing tips can be found at Hints on OCA/OCP exam technique
The following resources are also very helpful, but are not free:
An Oracle IZ0-052 practice exam can be purchased from Kaplan Selftest
I also found several great Oracle books on Safari Books Online and added them to
My favorite Oracle book is "OCA: Oracle Database 11g Administrator
Certified Associate Study Guide: (Exams1Z0-051 and 1Z0-052)" by Biju
With all these resources, how could I go wrong? Unfortunately, resources are
only good if you have time to review them.
As I write this article, I still don't have my OCA. In keeping with the
theory that the only constant is change, my job responsibilities changed
dramatically shortly after I made the commitment to complete my OCA and write
this article. As a result, I've had to temporarily give up my evening Oracle
OCA study time in favor of evening "paying work" time. Soon, I should
be able to resume my studies and (I hope) finally see that OCA certificate with
my name on it. I will hang it on my cubicle wall, next to my DB2 certifications
and my CISSP certification (near the black velvet Sad Clown painting). Yes,
it's true, I do want to wallpaper my cube with certifications. Doesn't every
Maybe in a few weeks, you will be taking an Oracle certification exam and
see a fellow test taker, proudly wearing her IBM Information Champion lapel
pin, as she attempts the exam that will show whether her preparation for the
OCA exam was successful or not. No need to wish her luck. She will be prepared.
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