| | Triggering OverviewYou can use Triggering if another site or application must be
notified when an event occurs in LN. For that purpose, the Triggering (TRG) module is available in
the Data Director (da) package. This module is a small component in LN that does the
following: - Receives an event.
- Checks whether the event meets certain conditions.
- Takes a predefined action.
IMPORTANT TERMS | Term | Description | | Event | An event is a message that states that something happened. An event
can for example be the creation of a new sales order, the change of a price, or
the receipt of a payment. In addition to the type of event, the event also
contains data related to the event, such as the identifier of the object on
which the event occurred, for example, an order number, and the data that was
changed. For more information on events, refer to Chapter 3, "Event handling"
in the User's Guide for Triggering. | | Condition | Conditions are used because not all events
are valid. For example, notification of a newly created order might only be
required if the order is entered manually. Notification of a change might only
be required if a particular status is reached. | | Action | The action describes what you must do if an
event occurs. This can, for example, be the execution of a program or the
creation of an XML file that the receiving application can pick up. |
ORIGIN OF EVENTS An event can be generated from multiple sources, such as the
following: - LN sessions can create events: This requires a customization of these sessions.
This type of customization can be either visible to the user, for example, by
adding a button to a session, or invisible, for example, by adding lines to a
program script that creates an event if a specific situation occurs.
- Change events for created, changed, or deleted objects can be
created from the Exchange module. In case of deleted objects, an exchange job
runs regularly to collect changes on LN data and creates an event for each of these
changes. The changes are collected from the audit trail.
- You can use the triggering mechanism to synchronize regularly
complete data sets, because the Exchange module can regularly read a specific
set of data and create the corresponding events that describe the current
status of the data. You can use this method to notify another application or
site from the current status of the data set, if the data set is small. For
this reason, keeping track of the changes is not worthwhile.
- You can generate events using a timer. As a result, an event
occurs regularly, irrespective of the LN application or LN data. In that case,
the action must specify what must happen.
RUNTIME ACTIONS The following example illustrates what happens at runtime in
the exchange-based scenario: - Changes are made to the OLTP (online transaction processing)
database by users or by other processes that result in changes.
- Changes on relevant tables are logged in the audit
trail.
- The exchange process runs regularly in a job.
- The exchange process picks up the changes from the audit trail
and processes the changes according to the defined scheme.
- The exchange scheme creates XML events for the changes and
forwards these to the triggering component.
- The triggering component receives the event, checks what
action must be carried out upon that event and performs this action.
RELATION WITH Workflow You can use the Triggering module to trigger business processes
in Workflow. In
that case, you can use the Workflow Management (tgwfm) sessions to generate the
Exchange schemes and triggers. For details, refer to the Workflow online Help
and to the User Manuals for the Workflow Extension for LN. SESSIONS The triggering solution consists of the following
sessions: MORE INFORMATION For detailed information on the Triggering module, refer to the
User's Guide for Triggering. For information on the scripts that are used in the triggering
module, refer to: | |