Table of contents

[Home] [W3C Specs]

1.1 Purpose

1.2 Dependencies on Other Specifications

1.3 Documentation Conventions and Terminology

2 Conceptual Framework

2.1 Overview of XML Schema

2.2 XML Schema Abstract Data Model

2.2.1 Type Definition Components

2.2.2 Declaration Components

2.2.3 Model Group Components

2.2.4 Identity-constraint Definition Components

2.2.5 Group Definition Components

2.2.6 Annotation Components

2.3 Constraints and Validation Rules

2.4 Conformance

2.5 Names and Symbol Spaces

2.6 Schema-Related Markup in Documents Being Validated

2.6.1 xsi:type

2.6.2 xsi:nil

2.6.3 xsi:schemaLocation, xsi:noNamespaceSchemaLocation

2.7 Representation of Schemas on the World Wide Web

3 Schema Component Details

3.1 Introduction

3.1.1 Components and Properties

3.1.2 XML Representations of Components

3.1.3 The Mapping between XML Representations and Components

3.1.4 White Space Normalization during Validation

3.2 Attribute Declarations

3.2.1 The Attribute Declaration Schema Component

3.2.2 XML Representation of Attribute Declaration Schema Components

3.2.3 Constraints on XML Representations of Attribute Declarations

3.2.4 Attribute Declaration Validation Rules

3.2.5 Attribute Declaration Information Set Contributions

3.2.6 Constraints on Attribute Declaration Schema Components

3.2.7 Built-in Attribute Declarations

3.3 Element Declarations

3.3.1 The Element Declaration Schema Component

3.3.2 XML Representation of Element Declaration Schema Components

3.3.3 Constraints on XML Representations of Element Declarations

3.3.4 Element Declaration Validation Rules

3.3.5 Element Declaration Information Set Contributions

3.3.6 Constraints on Element Declaration Schema Components

3.4 Complex Type Definitions

3.4.1 The Complex Type Definition Schema Component

3.4.2 XML Representation of Complex Type Definitions

3.4.3 Constraints on XML Representations of Complex Type Definitions

3.4.4 Complex Type Definition Validation Rules

3.4.5 Complex Type Definition Information Set Contributions

3.4.6 Constraints on Complex Type Definition Schema Components

3.4.7 Built-in Complex Type Definition

3.5 AttributeUses

3.5.1 The Attribute Use Schema Component

3.5.2 XML Representation of Attribute Use Components

3.5.3 Constraints on XML Representations of Attribute Uses

3.5.4 Attribute Use Validation Rules

3.5.5 Attribute Use Information Set Contributions

3.5.6 Constraints on Attribute Use Schema Components

3.6 Attribute Group Definitions

3.6.1 The Attribute Group Definition Schema Component

3.6.2 XML Representation of Attribute Group Definition Schema Components

3.6.3 Constraints on XML Representations of Attribute Group Definitions

3.6.4 Attribute Group Definition Validation Rules

3.6.5 Attribute Group Definition Information Set Contributions

3.6.6 Constraints on Attribute Group Definition Schema Components

3.7 Model Group Definitions

3.7.1 The Model Group Definition Schema Component

3.7.2 XML Representation of Model Group Definition Schema Components

3.7.3 Constraints on XML Representations of Model Group Definitions

3.7.4 Model Group Definition Validation Rules

3.7.5 Model Group Definition Information Set Contributions

3.7.6 Constraints on Model Group Definition Schema Components

3.8 Model Groups

3.8.1 The Model Group Schema Component

3.8.2 XML Representation of Model Group Schema Components

3.8.3 Constraints on XML Representations of Model Groups

3.8.4 Model Group Validation Rules

3.8.5 Model Group Information Set Contributions

3.8.6 Constraints on Model Group Schema Components

3.9 Particles

3.9.1 The Particle Schema Component

3.9.2 XML Representation of Particle Components

3.9.3 Constraints on XML Representations of Particles

3.9.4 Particle Validation Rules

3.9.5 Particle Information Set Contributions

3.9.6 Constraints on Particle Schema Components

3.10 Wildcards

3.10.1 The Wildcard Schema Component

3.10.2 XML Representation of Wildcard Schema Components

3.10.3 Constraints on XML Representations of Wildcards

3.10.4 Wildcard Validation Rules

3.10.5 Wildcard Information Set Contributions

3.10.6 Constraints on Wildcard Schema Components

3.11 Identity-constraint Definitions

3.11.1 The Identity-constraint Definition Schema Component

3.11.2 XML Representation of Identity-constraint Definition Schema Components

3.11.3 Constraints on XML Representations of Identity-constraint Definitions

3.11.4 Identity-constraint Definition Validation Rules

3.11.5 Identity-constraint Definition Information Set Contributions

3.11.6 Constraints on Identity-constraint Definition Schema Components

3.12 Notation Declarations

3.12.1 The Notation Declaration Schema Component

3.12.2 XML Representation of Notation Declaration Schema Components

3.12.3 Constraints on XML Representations of Notation Declarations

3.12.4 Notation Declaration Validation Rules

3.12.5 Notation Declaration Information Set Contributions

3.12.6 Constraints on Notation Declaration Schema Components

3.13 Annotations

3.13.1 The Annotation Schema Component

3.13.2 XML Representation of Annotation Schema Components

3.13.3 Constraints on XML Representations of Annotations

3.13.4 Annotation Validation Rules

3.13.5 Annotation Information Set Contributions

3.13.6 Constraints on Annotation Schema Components

3.14 Simple Type Definitions

3.14.1 (non-normative) The Simple Type Definition Schema Component

3.14.2 (non-normative) XML Representation of Simple Type Definition Schema Components

3.14.3 (non-normative) Constraints on XML Representations of Simple Type Definitions

3.14.4 Simple Type Definition Validation Rules

3.14.5 Simple Type Definition Information Set Contributions

3.14.6 Constraints on Simple Type Definition Schema Components

3.14.7 Built-in Simple Type Definition

3.15 Schemas as a Whole

3.15.1 The Schema Itself

3.15.2 XML Representations of Schemas

3.15.3 Constraints on XML Representations of Schemas

3.15.4 Validation Rules for Schemas as a Whole

3.15.5 Schema Information Set Contributions

3.15.6 Constraints on Schemas as a Whole

4 Schemas and Namespaces: Access and Composition

4.1 Layer 1: Summary of the Schema-validity Assessment Core

4.2 Layer 2: Schema Documents, Namespaces and Composition

4.2.1 Assembling a schema for a single target namespace from multiple schema definition documents

4.2.2 Including modified component definitions

4.2.3 References to schema components across namespaces

4.3 Layer 3: Schema Document Access and Web-interoperability

4.3.1 Standards for representation of schemas and retrieval of schema documents on the Web

4.3.2 How schema definitions are located on the Web

5 Schemas and Schema-validity Assessment

5.1 Errors in Schema Construction and Structure

5.2 Assessing Schema-Validity

5.3 Missing Sub-components

5.4 Responsibilities of Schema-aware Processors

Appendices

A Schema for Schemas (normative)

B References (normative)

C Outcome Tabulations (normative)

C.1 Validation Rules

C.2 Contributions to the post-schema-validation infoset

C.3 Schema Representation Constraints

C.4 Schema Component Constraints

D Required Information Set Items and Properties (normative)

E Schema Components Diagram (non-normative)

F Glossary (non-normative)

G DTD for Schemas (non-normative)

H Analysis of the Unique Particle Attribution Constraint (non-normative)

I References (non-normative)

J Acknowledgements (non-normative)

1.1 Purpose

Purpose

The purpose of XML Schema: Structures is to define the nature of XML schemas and their component parts, provide an inventory of XML markup constructs with which to represent schemas, and define the application of schemas to XML documents.

The purpose of an XML Schema: Structures schema is to define and describe a class of XML documents by using schema components to constrain and document the meaning, usage and relationships of their constituent parts: datatypes, elements and their content and attributes and their values. Schemas may also provide for the specification of additional document information, such as normalization and defaulting of attribute and element values. Schemas have facilities for self-documentation. Thus, XML Schema: Structures can be used to define, describe and catalogue XML vocabularies for classes of XML documents.

Any application that consumes well-formed XML can use the XML Schema: Structures formalism to express syntactic, structural and value constraints applicable to its document instances. The XML Schema: Structures formalism allows a useful level of constraint checking to be described and implemented for a wide spectrum of XML applications. However, the language defined by this specification does not attempt to provide all the facilities that might be needed by any application. Some applications may require constraint capabilities not expressible in this language, and so may need to perform their own additional validations.

[Next Chapter] [Home]