Table of contents

Appendices

3 Types

<definitions>
  <types>
    <documentation />?
    [extension elements]*
  </types>
</definitions>

The content of messages and faults may be constrained using type system components. These constraints are based upon a specific data model, and expressed using a particular schema language.

Although a variety of data models can be accommodated (through WSDL extensions), this specification only defines a means of expressing constraints based upon the XML Infoset [XMLInfoSet]. Furthermore, although a number of alternate schema languages can be used to constrain the XML Infoset (as long as they support the semantics of either embedding or importing schema), this specification only defines the use of XML Schema [XMLSchemaP1], [XMLSchemaP2].

Specifically, the {element declarations} and {type definitions} properties of the Definitions component are collections of imported and embedded schema components that describe Infoset element information items.

When extensions are used to enable the use of a non-Infoset data model, or a non-Schema constraint language, the wsdl:required attribute information item MAY be used to require support for that extension.

NOTE: 

Support for the W3C XML Schema Description Language [XMLSchemaP1],[XMLSchemaP2] is required of all processors.

The schema components contained in the {element declarations} property of [The Definitions Component] provide the type system used for Message Reference and Interface Fault components. Message Reference components indicate their structure and content by using the standard attribute information items element, or for alternate schema languages in which these concepts do not map well, by using alternative attribute information item extensions. Interface Fault components behave similarly. Such extensions should define how they reference type system components. Such type system components MAY appear in additional collection properties on [The Definitions Component].

The schema components contained in the {type definitions} property of [The Definitions Component] provide the type system used for constraining the values of properties described by Property components. Extensions in the form of attribute information items can be used to refer to constraints (type definitions or analogous constructs) described using other schema languages or type systems. Such components MAY appear in additional collection properties on [The Definitions Component].

The types element information item encloses data type definitions, based upon the XML Infoset, used to define messages and has the following Infoset properties:

• A [local name] of types.

• A [namespace name] of http://www.w3.org/2004/08/wsdl.

• Zero or more namespace qualified attribute information items in its [attributes] property. The [namespace name] property of such attribute information items MUST NOT be http://www.w3.org/2004/08/wsdl

• Zero or more element information items amongst its [children] as follows:

  • An OPTIONAL documentation element information item (see [Documentation]) in its [children] property.

  • Zero or more element information items from among the following, in any order:

    • xs:import element information items

    • xs:schema element information items

    • Other namespace qualified element information items whose namespace is NOT http://www.w3.org/2004/08/wsdl