Table of contents

Appendices

3.2 Using Other Schema Languages

Since it is unreasonable to expect that a single schema language can be used to describe all possible message parts and their constraints, WSDL allows alternate schema languages to be specified via extensibility elements. An extensibility element information item MAY appear under the types element information item to identify the schema language employed, and to locate the schema instance defining the grammar for message parts. Depending upon the schema language used, an element information item MAY be defined to allow embedding, if and only if the schema language can be expressed in XML. A specification of extension syntax for an alternative schema language MUST include an element information item definition, intended for inclusion in the Types Component, which references, names, and locates the schema instance (an "import" element information item). See [Examples of Specifications of Extension Elements for Alternative Schema Language Support.] for examples of using other schema languages.