Finding the Compromise – the Adapter Framework - Applied SOA Patterns on the Oracle Platform - page 384

-----------------------------------------------------------------------------------------
Put your values here below, up to 15
---------------------------------------------------------------------------------------*/
--6
new_event_attr.ParameterName :=
'OLD_ADDRESS_ID';
new_event_attr.ParameterValue :=
'old_address';
new_event_attr.BusinessName := 'Old
Address';
new_event_attr.ParameterType := 'VARCHAR2';
new_event_attr.ParameterOrder := 6;
new_event_attr.ParameterStageIndex := 1;
new_event_attr.ParameterStage := 'old';
v_EHS_evtcontext.EXTEND;
v_EHS_evtcontext(6) := new_event_attr;
.....
As you can see, the first five are OEBS-specific FND_GLOBAL attributes, and you have
15 more elements of your own. The register_event procedure just puts the basic
event record into the event log table. That's it, registration complete, and no more activit-
ies on the Entity table whatsoever. A completely separate process, based on Oracle Job
(Scheduler) will scan this table for the new entries and decide on further steps. We have
completely decoupled event registration and further object construction. From the number
of processing flags in the event record, you can understand that locking mechanism is es-
tablished on the Event Registration table (see flags v_retry_attempts ,
v_transferred and v_processed in the previous code) and you could have as
many event handlers as you like, implementing the parallel processing: vertically (per Ob-
jects type: one for Orders, one for Invoices, and so on) and horizontally (by number of re-
cords—500 records per handler, for instance). Therefore, event registration and event re-
cognition parts will never be your bottleneck. However, one problem has to be mentioned.
Even though the triggers and event log table footprints are so insignificant that we can
hardly consider this technique as invasive, their implementation can be problematic in en-
vironments that do not entirely belongs to us. If the vendor is sensitive to his internal DB
structure, you will have to find noninvasive ways of events registration.