Re: Trigger programs./RI

[John Carr <74711.77@xxxxxxxxxxxxxx>]

Tim
There is a difference between Triggers & R/I.   

 In a trigger program, lets say  you want to do some kind of 
edit on the record being passed (record image that was Updated/Added/Deleted)
and lets say
you find something wrong and you don't want the function to happen.

First you must be triggering *BEFORE for the event time and second if you want
to signal to the 
program above you not to do the data base operation,   YES you must issue an
*EXCAPE type 
message to "crash and burn" the stack above you.   I think IBM's understanding
was that 
"Of course everyone checks every I/O operation for an error(*IN in the less than
or middle position)  already and takes the appropriate action RIGHT?   

 This in effect does not allow you to do editing on the record being passed to
you.    HOWEVER there are a million other valuable uses for triggers besides
secondary edits.  Its a great tool and I highly recommend you try playing with
it in your own library and think of some creative productional uses for it in
your shop.  Nothing to be afraid of.

Now   R/I is a different matter.    Since I've written a paragraph already  and
everyone is most likely bored of my ramblings ,  I'll let someone else explain
the pitfalls of this other powerful DB tool.

John P. Carr  CDP
EdgeTech 

Message text written by INTERNET:Tim_Lennon/Thomas_Miller_at_Mutual@mutual.co.uk
>
>   From: Tim Lennon on 16/05/97 15:03
>  Does anyone else have any input on this? I have been given to
>  understand that the problem with using a trigger program and/or R/I
>  over a file is that RPGs will crash and burn if they attempt a
>  database function which is porhibited by the constraints.
>  How do people deal with this?
>  Tim Lennon.
 > A/P. Thomas Miller and Co.
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