Buck

do you have an example

On Mon, Oct 5, 2015 at 4:01 PM, Buck Calabro <kc2hiz@xxxxxxxxx> wrote:

On 10/4/2015 5:13 AM, Henrik Rützou wrote:
To my best knowledge a trigger, even if it is executed before the I/O,
isn’t able to prevent the I/O being done so triggers are limited unless
you
at the same time as you build in a validation and a way to message back
to
the caller (that is not standard in a trigger) and combines it with
commit/rollback in the caller.

One can use a Before Trigger to prevent an I/O operation! To signal a
failure, have the trigger send an escape message to the caller, which
will be the database manager. The DB manager sees that and percolates
an I/O error back up to the HLL. In the case of an RPG program
performing an UPDATE, the UPDATE operation will receive the I/O error
and this is how the program knows the I/O did not happen.

--
--buck

--
This is the Web Enabling the IBM i (AS/400 and iSeries) (WEB400) mailing
list
To post a message email: WEB400@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/web400
or email: WEB400-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/web400.





As an Amazon Associate we earn from qualifying purchases.

This thread ...

Follow-Ups:
Replies:

Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.