Inbound support

The Adapter for JDBC supports inbound event management with asynchronous event delivery.

Asynchronous event delivery is accomplished through use of an event table, called an event store, and a staging table, or event distribution table. For any changes in the user tables, the application populates the event table in the enterprise information system (EIS). Updates are made by placing triggers on the user tables that record events in the event table corresponding to the updates to the user table.

The staging table is deployed as part of an XA-compliant database, such as Cloudscape(TM), which is included with WebSphere(R) Application Server, Version 6.0. When an event is retrieved from the EIS, a reference to the event is written to the staging table for each active endpoint. Each event in the staging table is delivered to its corresponding endpoint as part of a unique XA transaction controlled by the application server. When the endpoint consumes its event and the transaction is committed, the reference to the event in the staging table is removed for that and only that endpoint.

The event table is described in the following table.

Event table

Name Type Description
event_id Number Unique Eventid that is a Primary key for the table
object_key String Delimited string that contains keys for the business object (not null)
object_name String Name of the business object (not null)
object_function String Operation corresponding to the event (Delete, Create, Update, and so on (not null)
event_priority Number Not null
event_time Date Date and time when event was generated
event_status Number In Progress, Success, Failure, and so on (not null)
event_comment String Description

Event processing in the Adapter for JDBC

The complete flow of event processing by the Adapter for JDBC is depicted in four steps that are shown in the following four figures.

The first figure shows the first step, in which the event has been detected in the EIS and the record has been added to the staging table for each active endpoint.

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The next figure shows the second step, in which the event in the EIS is marked in-progress.

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The next figure shows the third step, in which the event is published to all active endpoints, by using the staging table as a guide for which endpoints require delivery. Simultaneously, the event is deleted from the staging table as part of individual XA transactions encompassing each endpoint and its specific record in the staging table. In effect, each endpoint is isolated from the others in terms of its receipt and processing of the event.

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In the fourth step, once all endpoints have received the event, as determined by a lack of remaining references in the staging table, the original event is deleted from the EIS. Steps 1 through 4 repeat for every event.

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Last updated: Thu Mar 23 13:24:29 2006

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