Event detection refers to the collection of
processes that
notify the adapter of SAP application object events. Notification
includes, but is not limited to, the type of the event (object and
operation) and the data key required for the external system to retrieve
the associated data.
Event detection is the process of identifying
that an event was
generated in the SAP application. Typically, adapters use database
triggers to detect an event. However, because the SAP application
is tightly integrated with the SAP database, SAP allows very limited
access for direct modifications to its database. Therefore, the event-detection
mechanisms are implemented in the application transaction layer above
the database.
Adapter-supported event detection
mechanisms
The
four event-detection mechanisms supported by the adapter are described
in the following list:
- Custom Triggers, which are implemented
for a business process
(normally a single SAP transaction) by inserting event detection code
at an appropriate point within the SAP transaction.
- Batch
programs, which involve developing an ABAP program containing
the criteria for detecting an event.
- Business workflows, which
use the object-oriented event detection
capabilities of SAP.
- Change pointers, a variation of business
workflows, which use
the concept of change documents to detect changes for a business process.
All these event-detection mechanisms support
real-time triggering and retrieval of objects. In addition, custom
triggers and batch programs provide the ability to delay the retrieval
of events. An event whose retrieval is delayed is called a future
event.
Note: Each event detection mechanism has advantages and disadvantages
that need to be considered when designing and developing a business
object trigger. Keep in mind that these are only a few examples of
event detection mechanisms. There are many different ways to detect
events.
After you determine the business process to
support (for example, sales quotes or sales orders) and determine
the preferred event-detection mechanism, implement the mechanism for
your business process.
Note: When implementing an event detection
mechanism, it is a good idea to support all of the functionality for
a business process in one mechanism. This limits the impact in the
SAP application and makes event detection easier to manage.
See
the related topics on implementing the event-detection mechanisms
in the Performing prerequisite tasks specific to an interface section.
Event table
Events that are detected are
stored in an SAP application table. This event table is delivered
as part of the ABAP component. The event table structure is as follows.
Table 1. Event table fields| Name |
Type |
Description |
|---|
| event_id |
NUMBER |
Unique event ID that is a primary key
for the table. |
| object_name |
STRING |
business object name. |
| object_key |
STRING |
Delimited string that contains the
keys for the business object. |
| object_function |
STRING |
Operation corresponding to the event
(Delete, Create, or Update). |
| event_priority |
NUMBER |
Any positive integer to denote the
priority of the event. |
| event_time |
DATE |
Date
and time when the event was generated. |
| event_status |
NUMBER |
Event processing status. Possible values
are:- 0 - Ready for poll
- 1 - Event delivered
- 2
- Event prequeued
- 3 - Event in progress
- 4 - Event
locked
- -1 - Event failed
|
| Xid |
STRING |
Unique XID (transaction ID) value for
assured-once delivery. |
| event_user |
STRING |
User who created the event. |
| event_comment |
STRING |
Description
of the event. |