Once upon a time there was a kingdom called Userville. The people
in the kingdom were impatient and wanted to know everything about
everything—they could never get enough information. Life was difficult and the
people were unhappy because data was often lost, and even when it was
available, it was often inaccurate and not easy to access.
The King decided to purchase
DB2, an advanced tool for storing and retrieving data. With DB2 the Users could
process their data and turn it into information. “This,” he thought, “should
keep the people happy. DB2 will solve all my problems.” But he soon found out
that special knowledge was necessary to make DB2 work its wonders. Nobody in
Userville knew how to use it properly.
Luckily, a grand Wizard living
in a nearby kingdom knew many mystical secrets for retrieving data. These
secrets were a form of magic called SQL. The King of Userville summoned the
Wizard, offering him many great treasures if only he would help the poor Users
in Userville.
The Wizard soon arrived,
determined to please. Armed with nothing more than SQL and a smile, the Wizard
strode to the terminal and uttered the magic words:
SELECT
E.EMPNO, E.FIRSTNME, E.LASTNAME, D.DEPTNO, D.DEPTNAME
FROM DSN81010.DEPT D,
DSN81010.EMP E
WHERE E.WORKDEPT = D.DEPTNO;
A crowd gathered and applauded
as the desired information began pumping out of the terminal. “More, more,”
shouted the data-starved masses. The Wizard gazed into the screen, and with
amazing speed effortlessly produced report after report. The King was overheard
to say, “You know, this is just too good to be true!” Everybody was happy. The
Users had their share of information, the King had a peaceful kingdom, and the
Wizard had his treasures and the respect of the Users.
For many months, the Users
were satisfied with the magic of the great Wizard. Then, one day, the Wizard
disappeared…in a jet to the West Coast for 150 grand a year—and a bunch of
stock options. The people of the kingdom began to worry. “How will we survive
without the magic of the Wizard? Will we have to live, once again, without our
precious information?” The Wizard’s apprentice tried to silence the crowd by
using his magic, but it wasn’t the same. The information was still there, but
it wasn’t coming fast enough or as effortlessly. The apprentice was not yet as
skilled as the great Wizard who had abandoned the kingdom. But, as luck would
have it, one day he stumbled upon the great Wizard’s diary. He quickly absorbed
every page and soon was invoking the Wizard’s magic words. And all was well
again.
Well, life is not always that
simple. Departing Wizards do not often leave behind documentation of their
secrets. But...
Many of you who have purchased my book, DB2 Developer's Guide, will recognize the story recounted above because it starts the book off in Chapter 1. The idea being that the rest of the book is the Wizard's guide to DB2 for z/OS...
If you use DB2 for z/OS for a living and you have never read DB2 Developer's Guide, maybe it is time to treat yourself to an early present for the holidays? The book comprises more than 1500 pages of in-depth DB2 knowledge and information. Over the course of 46 chapters DB2 Developer's Guide covers:
- SQL Techniques, Tips, and Tricks
- DB2 Application Development
- DB2 In-Depth (an under the covers look)
- DB2 Perfromance Monitoring
- DB2 Utilities and Commands
- DB2 Tools and Organizational Issues
- Distributed DB2
- and much, much more
The book has been in print for more than 20 years now and has been published in 6 different editions over that span. The current edition is the 6th edition published by IBM Press.
So continue and take the next
step toward becoming a DB2 Wizard by getting your own copy today!
Happy New Year !!..
ReplyDeleteI am in search of one answer regarding locking.I was going through the link http://www.toadworld.com/platforms/ibmdb2/w/wiki/6655.lock-sizes-and-types.aspx and the first para says " DB2 does not take transaction locks on indexes at all, but uses data-only locking. "
Could you please explain a bit what is a 'data only locking'. Also, when data is fetched from index only, does db2 apply the same locks (S,IS) on the index like it does on TS,or Table?.. Would be waiting for your answer.. Thanks in advance!!
Here is a link for you to read through on DB2 data only locking: http://www-01.ibm.com/support/knowledgecenter/SSEPEK_11.0.0/com.ibm.db2z11.doc.perf/src/tpc/db2z_indexanddataonlylocks.dita
ReplyDelete