ISO/IEC 19757-11:2011

Information technology - Document Schema Definition Languages (DSDL) - Part 11: Schema association

ISO/IEC 19757-11:2011 allows schemas using any schema definition language to be associated with an XML document by including one or more processing instructions with a target of xml-model in the document's prolog.

Technologies de l'information — Langages de définition de schéma de documents (DSDL) — Partie 11: Association de schémas

General Information

• Status: Published
• Publication Date: 27-Oct-2011
• ICS: 35.240.30 - IT applications in information, documentation and publishing
• Technical Committee: ISO/IEC JTC 1/SC 34 - Document description and processing languages
• Drafting Committee: ISO/IEC JTC 1/SC 34 - Document description and processing languages
• Current Stage: 9093 - International Standard confirmed
• Start Date: 16-Jun-2022
• Completion Date: 30-Oct-2025

Overview - ISO/IEC 19757-11:2011 (Schema association)

ISO/IEC 19757-11:2011 defines a schema-agnostic way to associate one or more external schemas with an XML document by means of an xml-model processing instruction placed in the document prolog. It specifies the syntax, required parsing behavior and the pseudo-attributes that convey schema location and metadata (for example, href, type, schematypens, charset, title, group, phase). The standard is aligned with the W3C "Associating Schemas with XML documents" specification and is part of the DSDL family for XML schema definition and validation.

Key topics and technical requirements

• xml-model processing instruction: must appear in the document prolog (before the root element) with target xml-model. Processors parse its pseudo-attributes using the parsing rules from the W3C xml-stylesheet/ASSOCSS recommendation.
• Mandatory and optional pseudo-attributes:
  • href (required): an IRI-reference pointing to the schema (RFC 3987).
  • type: media/content type of the schema (advisory; defaults to application/xml if omitted).
  • schematypens: namespace identifying the schema language (helps determine language like RELAX NG, W3C XML Schema, Schematron).
  • charset, title, group, phase: charset names must match IANA registry; group enables schema grouping selection; phase is used with Schematron.
• Conformance for processors: an xml-model processor must report the full parsing result to the application and may be part of a larger XML tool. If parsing pseudo-attributes fails, the PI is not an xml-model instruction.
• Multiple schemas & precedence: multiple xml-model PIs are allowed; the standard does not mandate processing order nor dictate interaction with xsi:schemaLocation/xsi:noNamespaceSchemaLocation.
• Non-normative: examples and annex guidance (e.g., suggested schematypens values) are informative only.

Applications - who uses it and why

• XML tool and editor developers: attach validation schemas directly in documents for content completion and editor-driven validation.
• Validator and processor implementers: discover schema locations and types programmatically via xml-model.
• Technical architects and standards authors: embed authoritative schema associations in sample or canonical documents.
• Use cases include validation workflows, data binding, editorial tools, and archival documents that carry explicit schema references.

Related standards and references

• ISO/IEC 19757 (DSDL series) - Part 3 (Schematron), Part 4 (NVDL), etc.
• W3C "Associating Schemas with XML documents" (xml-model)
• XML 1.0 (W3C), ASSOCSS (pseudo-attribute parsing), IETF RFC 3987 (IRIs), IANA character set registry

Keywords: ISO/IEC 19757-11, xml-model, schema association, DSDL, xml schema, RELAX NG, Schematron, processing instruction, schematypens, href, XML validation.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 19757-11
First edition
2011-11-01
Information technology — Document
Schema Definition Languages (DSDL) —
Part 11:
Schema association
Technologies de l'information — Langages de définition de schéma de
documents (DSDL) —
Partie 11: Association de schémas

Reference number
©
ISO/IEC 2011
©  ISO/IEC 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2011 – All rights reserved

Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Conformance requirements . 1
4 The xml-model processing instruction . 2
Annex A (informative) Examples . 4
Annex B (informative) Suggested use of schematypens for determining schema language . 5
© ISO/IEC 2011 – All rights reserved iii

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 19757-11 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 34, Document description and processing languages.
ISO/IEC 19757 consists of the following parts, under the general title Information technology — Document
Schema Definition Languages (DSDL):
— Part 1: Overview [Technical Report]
— Part 2: Regular-grammar-based validation — RELAX NG
— Part 3: Rule-based validation — Schematron
— Part 4: Namespace-based Validation Dispatching Language (NVDL)
— Part 5: Extensible Datatypes
— Part 7: Character Repertoire Description Language (CREPDL)
— Part 8: Document Semantics Renaming Language (DSRL)
— Part 9: Namespace and datatype declaration in Document Type Definitions (DTDs)
— Part 11: Schema association
iv © ISO/IEC 2011 – All rights reserved

Introduction
There are several document schema definition languages in common use today that can be used to specify
one or more validation processes performed against Extensible Markup Language (XML) documents. Some
schema languages provide their own syntax for associating schemas with documents (DTD, W3C XML
Schema) and some languages (RELAX NG, Schematron) do not provide schema association mechanisms at
all. The purpose of this part of ISO/IEC 19757 is to define a common, schema-agnostic syntax for associating
schema documents written in any schema definition language with a given XML document.
This part of ISO/IEC 19757 defines the syntax and processing expectations for an xml-model processing
instruction. Such processing instructions associate one or more schemas with the XML document in which
they are present. The associated schemas may be written in any schema definition language. Applications
can use the associated schemas for any purpose including those such as document validation, content
completion in interactive editors, or creating models for data binding. Presence of an xml-model processing
instruction is not in itself an instruction to any processor to validate the document, nor is it a statement that the
document is not to be processed without validation. It is a declarative statement of a relationship between the
document and one or more external schemas. This part of ISO/IEC 19757 does not prescribe what, if
anything, an application does with an xml-model processing instruction. The presence of an xml-model
processing instruction referencing a Document Type Definition (DTD) does not affect the validity of the
document which contains it.
This part of ISO/IEC 19757 is not meant as a replacement for other technologies that provide more general
and indirect schema association features like Namespace-based Validation Dispatching Language (NVDL)
and XProc. This part of ISO/IEC 19757 is complementary technology which can be used when it is necessary
to store ad hoc schema associations directly inside an XML document.
The technical content of this part of ISO/IEC 19757 has been developed jointly with W3C. It is expected to be
identical to that of W3C's Associating Schemas with XML documents 1.0.
© ISO/IEC 2011 – All rights reserved v

INTERNATIONAL STANDARD ISO/IEC 19757-11:2011(E)

Information technology — Document Schema Definition
Languages (DSDL) —
Part 11:
Schema association
1 Scope
This part of ISO/IEC 19757 allows schemas using any schema definition language to be associated with an
XML document by including one or more processing instructions with a target of xml-model in the document's
prolog.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
[ASSOCSS] Associating Style Sheets with XML documents 1.0 (Second Edition). W3C, 28 October 2010.
Available at
[IANACHARSET] Character Sets, IANA, May 2007. Available at sets>
[ISO/IEC 19757-3] ISO/IEC 19757-3:2006, Information technology — Document Schema Definition
Languages (DSDL) — Part 3: Rule-based validation — Schematron
[IETF RFC3987] Internationalized Resource Identifiers (IRIs), M. Dürst, M. Suignard. IETF, January 2005.
Available at
[XML] Extensible Markup Language (XML) 1.0 (Fifth Edition), T. Bray, J. Paoli, C. Sperberg-McQueen, E.
Maler, F. Yergeau. W3C, November 2008. Available at
3 Conformance requirements
All diagrams, examples, and notes in this part of ISO/IEC 19757 are non-normative, as are all sections
explicitly marked non-normative. Everything else in this part of ISO/IEC 19757 is normative.
Documents
A document is considered to conform to this part of ISO/IEC 19757 if it satisfies all criteria in this part of
ISO/IEC 19757 that apply to documents.
xml-model processors
XML defines an application as a software module which receives the information content of an XML
document from an XML processor. An xml-model processor is such an application which processes XML
processing instructions in accordance with this part of ISO/IEC 19757.
© ISO/IEC 2011 – All rights reserved 1
...