SAP IDOC OUT BOUND TRIGGERS II

IDocs should be sent out at certain events. Therefore you have to define a trigger. A lot of consideration is required to determine the correct moment when to send out the IDoc. The IDoc can be triggered at a certain time or when an event is raised. R/3 uses several completely different methods to determine the trigger point.

There are messages to tell the system that there is an IDoc waiting for dispatching, there are log files which may be evaluated to see if IDocs are due to send and there can be a workflow chain triggered, which includes the sending of the IDoc.

The simplest way to create IDocs, is to write an ABAP. The individual ABAP can either be a triggering ABAP which runs at certain events, e.g. every night, or it can be an ABAP which does the complete IDoc creation from scratch.


A triggering ABAP would simply try to determine which IDocs need sending and
call the appropriate IDoc creation routines.

You may also imagine the ABAP to do all the job. As this is mostly reinventing the
wheel, it is not really recommended and should be reserved to situation, where the
other solution do not provide an appropriate mean.


You can use the R/3 message concept to trigger IDocs the same way as you trigger SAPscript printing.

One of the key tables in R/3 is the table NAST. This table records reminders written
by applications. Those reminders are called messages.

Every time when an applications sees the necessity to pass information to a third
party. a message is written to NAST. A message handler will eventually check the
entries in the table and cause an appropriate action.

The concept of NAST messages has originally been designed for triggering
SAPscript printing. The very same mechanism is used for IDocs, where the IDoc
processor replaces the print task, as an IDoc is only the paperless form of a printed
document.

The messages are usually be created using the condition technique, a mechanism
available to all major R/3 applications.

The conditions are set up the same way for any output media. So you may define a
condition for printing a document and then just change the output media from
printer to IDoc/EDI or ALE.

Creating NAST messages is a standard functionality in most of the SAP core
applications. Those applications - e.g. VA01, ME21 - perform calls to the central
function module MESSAGING of group V61B. The function module uses
customizing entries, mainly those of the tables T681* to T685*.

A NAST output message is stored as a single record in the table NAST. The record
stores all information that is necessary to create an IDoc. This includes mainly an
object key to identify the processed object and application to the message handler
and the sender and receiver information.


Creating NAST messages is a standard functionality in most of the SAP core
applications. Those applications - e.g. VA01, ME21 - perform calls to the central
function module MESSAGING of group V61B. The function module uses
customizing entries, mainly those of the tables T681* to T685*.


A NAST output message is stored as a single record in the table NAST. The record
stores all information that is necessary to create an IDoc. This includes mainly an
object key to identify the processed object and application to the message handler
and the sender and receiver information.