1. there are two kinds of DB triggers, PF and SQL table triggers.
There are indeed 2 kinds of triggers, but system and SQL triggers.
System-Triggers are written in an HLL (such as RPG, Cobol, CL or C) and
registered with the CL command ADDPFTRG or as external trigger with the
SQL-command CREATE TRIGGER
SQL-Triggers are purely written with SQL and created and registered in a
single step with the SQL-Command CREATE TRIGGER.
2. the PF trigger cannot detect an update to a specific field, while the SQL
trigger can execute when a change in a specific column is detected.
A system trigger is activated as soon as a record will be changed, Updated
or deleted. In an update trigger you can detect if a specific field changed,
because you have access to both, before and after image of the record.
A SQL trigger can be specified at the change of a specific field.
3. since my file is a PF and not an SQL table, I cannot use the SQL trigger
and must use the ADDPFTRG.
Wrong system triggers and SQL triggers can be activated for DDS described
physical files and SQL tables.
You do not have to change your file from DDS described to SQL defined and
vice versa.
For to get more information about triggers I'd suggest to read the following
redbooks:
Stored Procedures, Triggers, and User-Defined Functions on DB2 Universal
Database for iSeries
http://www.redbooks.ibm.com/abstracts/sg246503.html?Open
Modernizing IBM eServer iSeries Application Data Access - A Roadmap
Cornerstone
http://www.redbooks.ibm.com/abstracts/sg246393.html?Open
Mit freundlichen Grüßen / Best regards
Birgitta Hauser
"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"
-----Ursprüngliche Nachricht-----
Von: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] Im Auftrag von
MKirkpatrick@xxxxxxxxxxxxxxxxx
Gesendet: Thursday, August 23, 2007 19:43
An: midrange-l@xxxxxxxxxxxx
Betreff: Triggers
I have a PF where when a certain field is changed I wish to write a copy
of the record to another file. Obviously, I could do this in the RPG pgm
but prefer to not change the pgm.
I have been reading about triggers and would like some confirmation on a
couple things.
First, there are two kinds of DB triggers, PF and SQL table triggers.
Second, the PF trigger cannot detect an update to a specific field, while
the SQL trigger can execute when a change in a specific column is
detected.
Third, since my file is a PF and not an SQL table, I cannot use the SQL
trigger and must use the ADDPFTRG.
Fourth, if I were to change my PF to an SQL table, an SQL trigger would be
a good choice to address my issue.
Any other suggestions as to how to handle my situation are also welcome.
Thanks.
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