Re: Trigger programme without a trigger.

[CRPence <CRPbottle@xxxxxxxxx>]

  If the concept of the-program controls all I/O to the file is 
acceptable as an assumption, then the-program is best to *also* serve as 
the arbiter for any [triggered] action to perform in response to any I/O 
requests.  Since the trigger concept is nothing more than provision for 
additional logic being applied to an I/O event, then the-program simply 
needs to add the necessary logic for whichever I/O events require the 
additional action, such that the-program is the trigger [for additional 
logic].

  Since there is only a limited ability to ensure that the given 
assumption [that all I/O is via only one program] can be met, the future 
is not generally bleak for use of trigger programs.  That is because a 
trigger enables placing\deferring business logic in\to the database 
rather than merely hoping\assuming that all possible I/O will be via 
the-program.  When any application is able to open and perform I/O on 
the file without having applied the [same\expected] business rules, the 
failed assumption that the-program would have been the arbiter of all 
I/O activity, could be very problematic.

  Rather than the Database Open Exit, a nice feature to request might 
be an Open-Database file trigger.  An /open trigger/ could limit the 
scope of an open exit program, to only those files for which an explicit 
request had added an /open trigger/.  Either could be used as preventive 
for any application other than the-program, from opening the file.

Regards, Chuck

David FOXWELL wrote:
> Ok. Got a response as to why no trigger.
>
> Recently I asked for advice while creating a unique module for a new
> PF, which I took and I now have a module that does all the business
> logic and input/output on that new file.
>
> So now the reasoning is, since all input to the file has to pass by
> this module, the use of a trigger is superfluous. We just call the
> procedure at each modification of the file. The future looks bleak
> for trigger programs.
>
> Anyone still find a hole to pick with the idea?...