Schema extensions in the message model

This topic provides information on areas where the message model provides facilities which are beyond the XML Schema specification.

Messages

A message is a global element representing an entire message (rather than a structure within a message). Within a message definition file, a message is represented by a special global element which carries the extra information required by WebSphere Message Broker.

Composition

The message model adds the following compositions which are beyond the XML Schema specification. These extra compositions allow message models produced in earlier versions of the product to be supported.

orderedSet
A set of elements which must appear in the order in which they are listed. Groups are not allowed within an orderedSet. Elements can repeat, but duplicate element references are not allowed.
unorderedSet
A set of elements which can appear in any order. Groups are not allowed within an orderedSet. Unlike an all group, elements within an orderedSet are allowed to repeat. However, duplicate element references are not allowed.
message
A refinement of choice which is only allowed to contain a set of references to messages within the same message set. Groups and complex types with composition of message are used when modeling multipart messages.

Physical format information

If one or more physical formats are defined for a message set, the XML Schema objects within the message set can hold extra information about how they should be serialized.

Further information about XML Schema

For details about XML Schema, see XML Schema Part 0: Primer on the World Wide Web Consortium (W3C) Web site.