PowerHouse 4GL question: database locking

[Robert Mills]

Hi Walter,

QTP:

I agree with you on this.

QUIZ:

The only way I have found of preventing anybody from modifying the data
underneath me is to do a SET DBMODE 4 (modify allow concurrent read
(mode 6)), SET DBMODE 7 (exclusive read) or SET DBMODE 8 (read allow
concurrent read).

Mode 7 is extremely unfriendly to other users and should be avoided at
all costs.
Mode 4 gives you the same results as mode 8 but might incur some
additional database overhead.

Doing this can cause problems if everything else uses modes 1 and 5.

BTW: Did you know that version 8.49.E is now available? The main thing
you will get from doing this upgrade is the enhancement to QUIZ's report
line size. They have increased it from 264 to 32,767.

regards,
 
Robert W.Mills
Business Systems Development Analyst
Group Information Systems & Technology
Pinnacle Arvato
DDI: +44 (0)20 8309 3604 


-----Original Message-----
From:
powerh-l-bounces+robert.mills=pinnaclearvato.co.uk at lists.sowder.com
[mailto:powerh-l-bounces+robert.mills=pinnaclearvato.co.uk at lists.sowder.
com] On Behalf Of Walter J. Murray
Sent: 05 October 2007 05:15
To: HP3000-L at RAVEN.UTC.EDU; powerh-l at lists.sowder.com
Subject: PowerHouse 4GL question: database locking

Greetings,

I'm in the process of learning PowerHouse 4GL, and I'm trying to
understand how it manages database locking.

The environment is PowerHouse 8.39.C1 on MPE/iX 7.5, TurboIMAGE access
modes 1 and 5.

As I understand it, the default for QTP, whether in mode 1 or mode 5, is
to lock the whole database for the duration of the run.  The SET LOCK
statement can be used to change the locking level, or even to eliminate
locking completely (assuming the database is not being modified).
Unless locking is suppressed, interactive QTP attempts a conditional
lock every few seconds until it is satisfied or the user interrupts it;
batch mode QTP does an unconditional lock.  This is all documented in
the QTP Reference.

Please correct me if I don't have that completely right.

The question is about QUIZ.  As I understand it, the default access mode
is 5, but QUIZ doesn't do database locking.  Can this be right?  Is
there no way to make QUIZ lock the database while accessing it, as a
protection against other users modifying the same data that QUIZ is
accessing?

Thanks for bearing with my beginner's questions.

Walter  

Walter J. Murray




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