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Business Events and System Events

Business Events

A business event is a definable occurrence in a business scenario. It can be a common high-level occurrence, such as a customer placing an order. Alternatively, it can be a more specialized event, such as a customer exceeding a credit limit while placing an order. Some events can be triggered by changes in values, such as the share price for a particular stock exceeding a given value.

Business events define significant happenings that different parts of the business must register and act upon by using different applications. Oracle Integration Server integrates all applications that register and act upon a business event.

This appendix contains:

System Events

A system event is a point in the execution of a program at which an identifiable computing task takes place. Examples of system events include: writing to a file, inserting data into a database table, calling a subroutine, and instantiating a program thread.

A program that implements a particular business process usually includes many system events, and more than one of these system events can provide a suitable trigger to capture a particular business event.

Example: Raising an Order

Many integration applications contain the business event, Raise an Order. Several applications must subscribe to such an event because they must know that an order has been placed. A program in another application that captures orders contains program steps to perform these system events:

Get Accounting Date
Get Customer Address
Calculate Order Total
Insert into Order Header

Each of these system events occurs once per order. Any one of them can provide a suitable point at which to trigger the `Raise an Order' business event.

Distinctions between Business and System Events

There are three important distinctions between a business event and a system event:

The business event is a logical occurrence in a business scenario; the system event is the mechanism you use to recognize that the business event has occurred.
The business event is not influenced by the manner in which it is implemented in an application; the system event is a part of that implementation.
Messages that represent the business event must be constructed to provide information about the business event, not information about the system event that triggers it.

To emphasize business events in the integration solution, use a message-based strategy. To emphasize system events, use a strategy that implements data replication using messaging technologies.

Example: Emphasizing System Events

To integrate order processing, identify a business event called PlaceanOrder. If you have a system event named CallCreateOrderHeader, you can instantiate message creation immediately prior to or immediately after the call.

The message created contains all the information about the order, including order lines, customer details if necessary, the order total, and some or all of the information in the order header, which is created as part of the CreateOrderHeader subprogram.

The message is then published to the middleware as an instance of the Place an Order subject or topic. The middleware takes responsibility for routing the messages to those subscribing to the PlaceanOrder business event.

Example: Emphasizing Business Events

You identify a set of business events that relate to customer interactions, including one called RegistrationofaNew Customer.

Identify a system event that always occurs when you register a new customer. The system event is the insertion of a row into the customer table of the customer relationship management application.

The system event can raise the business event by creating a database trigger that starts when a row is inserted into the customer table. The database trigger calls a PL/SQL procedure or Java function that constructs a message to represent the registration of the new customer, by gathering information from other relational tables such as the address table and by calling other functions such as a credit rating calculation.

D Business Events and System Events