IBM E02HMLL-I Implementation Guide - Page 28

Within a data map, the conversion of source to destination attributes can be simple, or it can require establishing and maintaining relationships between data entities that are equivalent but which are represented differently in each different application, and so cannot be directly transformed. For example, for a Country attribute, one application might use a two-letter code (such as US, FR, or EG) while another application uses a numeral (such as 1, 2, or 3). To associate such attributes between different applications, you create a relationship definition, associating the data of the source and destination attributes. Most maps use one or more relationship definitions. Both map and relationship definitions reside in the repository of InterChange Server Express. Like business object definitions, relationship definitions function as specifications or templates for the instances that are created. Unlike instances of business objects, relationship instances persist, and are stored in special tables for each relationship. Each time the system receives a request to transform a given business object, it executes the associated map, and, depending upon the purpose of the transformation, creates one or more instances of its associated relationship definitions. Relationship instances created during map execution contain the runtime data from the attributes they associate, and this data is stored in relationship tables. Communication transport infrastructure Administrative interactions between distributed InterChange Server Express components are enabled by the Common Object Request Broker Architecture (CORBA). Content data transfers--that is, the business data that is being exchanged--can utilize either CORBA, or messaging technology provided by the Java Messaging Service (JMS) using WebSphere MQ queues. CORBA The Common Object Request Broker Architecture (CORBA) defines a set of standards and interfaces for distributed objects on a network. The Object Request Broker (ORB) is a set of libraries and other components that client applications and object servers use to communicate. InterChange Server Express uses the IBM Java ORB product. The ORB makes InterChange Server Express accessible to its clients, the connector agent, and System Manager. An InterChange Server ExpressExpress instance registers with the ORB's name service, from which a client obtains the information it needs to find and start interacting with the server. The client and server perform object-to-object interactions by means of the ORB's Interface Definition Language (IDL). At a transport level, they communicate by means of the Internet Inter-ORB Protocol (IIOP). ORB-based communication is typically used for the following purposes: v The Server Access Interface uses ORB-based communication to handle calls. v Optionally, in request/response interactions, collaborations and connectors use ORB-based communication to exchange business objects. v A connector agent uses ORB-based communication: 16 IBM WebSphere Business Integration Server Express and Express Plus: System Implementation Guide