RE: trigger program: can I fool a program into reading some selec t fields from another file?

Whoa!  That doesn't sound right, though I'm not too familliar with read
triggers....  My recollection is that a read trigger doesn't allow you to
change the data in the buffer.  The original questions where this came up
was something like "can you use a read trigger to keep some users from
seeing a column?".  Field level security....  As I recall, the answer was
no, the read trigger won't allow the buffer to be modified.

Oh, here's the exchange I think I am remembering....
http://archive.midrange.com/midrange-l/200201/msg02176.html

Eric DeLong
Sally Beauty Company
MIS-Project Manager (BSG)
940-898-7863 or ext. 1863



-----Original Message-----
From: Booth Martin [mailto:Booth@xxxxxxxxxxxx]
Sent: Monday, October 13, 2003 3:14 PM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: trigger program: can I fool a program into reading some
select fields from another file?


Yes you can. With a *BEFORE trigger. Chain to the new file, get the new
value, and change the output buffer of the record. 
 
However it will change the output buffer every time, even after it has
already been changed. I have the feeling I am missing something. Why not
just change the data in original file and be done with it?
 
 
 
---------------------------------------------------------
Booth Martin http://www.MartinVT.com
Booth@xxxxxxxxxxxx
---------------------------------------------------------
 
-------Original Message-------
 
From: Midrange Systems Technical Discussion
Date: Monday, October 13, 2003 2:45:40 PM
To: 'Midrange Systems Technical Discussion'
Subject: trigger program: can I fool a program into reading some select
fields from another file?
 
I have 1000+ programs reading a customer master file (the old cust file).
Can I add a trigger program which performs the following:
 
Whenever a program which reads a record from the old customer master file:
 
Read a different new customer file, get the customer's address from the new
file, and place the new address field into the address field in the old
customer record format.
 
Using this method, I could add a new file and not have to change any of the
many programs using the old customer master file.
 
If not a trigger program, is there any other method to accomplish this on
the Iseries?
 
I am aware of OVRDBF, but that will not allow me to grab select fields from
another file.
 
Also I am familiar with OPNQRYF, but that would require CL changes and would
limit the ease of implementation. Also, OPNQRYF would not support any logic
built into the record retrieval.
 
If I could use a trigger program, in theory, I could make a database change
which would require no changes to programs using the customer file.
 
Thanks!
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