IBM BPM, V8.0.1, All platforms > Authoring services in Integration Designer > Services and service-related functions > Access external services with adapters > Configure and using adapters > IBM WebSphere Adapters > Adapter Toolkit > Implementing code from the IBM WebSphere Adapter Toolkit > Data model
After-images versus deltas
Two distinct types of business objects, after-image and delta, are used to convey different kinds of information.
After-Image business objects can be thought of as a snapshot of the data in time; they reflect how the EIS entity looks (for inbound events) or is expected to look (for outbound requests). An after-image business object should represent the entire entity structure in the EIS.
For example, if an ORDER object with UPDATE verb is sent to the adapter, and the order has two ORDER_LINE children, the object in the EIS should be modified to reflect the input; if the EIS's representation of that object had only one ORDER_LINE, it will have two after the processing has completed.
Delta business objects reflect the specific changes that have occurred (for inbound events) or that the user wants affected (for outbound requests) in the EIS. Each business object contains a changeSummary structure that can store all the pending changes. For outbound requests, the adapter must interpret the change summary, making all applicable changes to the data.
For example, if an ORDER_LINE has been added to an ORDER object, the ORDER_LINE will appear as Created in the change summary. The adapter is responsible for finding that ORDER, and adding the ORDER_LINE to it.